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[75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.51.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:51:53 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 01/10] bpf: Support "sk_buff" and "xdp_buff" as valid kfunc arg types Date: Sun, 26 Feb 2023 00:51:11 -0800 Message-Id: <20230226085120.3907863-2-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The bpf mirror of the in-kernel sk_buff and xdp_buff data structures are __sk_buff and xdp_md. Currently, when we pass in the program ctx to a kfunc where the program ctx is a skb or xdp buffer, we reject the program if the in-kernel definition is sk_buff/xdp_buff instead of __sk_buff/xdp_md. This change allows "sk_buff <--> __sk_buff" and "xdp_buff <--> xdp_md" to be recognized as valid matches. The user program may pass in their program ctx as a __sk_buff or xdp_md, and the in-kernel definition of the kfunc may define this arg as a sk_buff or xdp_buff. Signed-off-by: Joanne Koong --- kernel/bpf/btf.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index fa22ec79ac0e..84cca8473873 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5683,6 +5683,10 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, * int socket_filter_bpf_prog(struct __sk_buff *skb) * { // no fields of skb are ever used } */ + if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0) + return ctx_type; + if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0) + return ctx_type; if (strcmp(ctx_tname, tname)) { /* bpf_user_pt_regs_t is a typedef, so resolve it to * underlying struct and check name again From patchwork Sun Feb 26 08:51:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152332 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23F37C64ED6 for ; Sun, 26 Feb 2023 08:52:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229549AbjBZIwC (ORCPT ); Sun, 26 Feb 2023 03:52:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbjBZIwA (ORCPT ); Sun, 26 Feb 2023 03:52:00 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8DAC11655; Sun, 26 Feb 2023 00:51:58 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id x34so3232715pjj.0; Sun, 26 Feb 2023 00:51:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=FiOQD6venFBWNf0Z4AQ/wrw3IlSiEPKwiV4MlNJJ/3s=; b=i3BptMSN8Twhn2K1balN381KlVwpMcAbO3KRarvcS8/Tu/lNqcPpQG8Q9wBVWXgP3Q hgKXw5Zpne4xc54WcMzId9W+QZ0dRP8G5I9I9YhcJuIhT8aaeBtJU0SkBs7Y3eVjtdxy LDmMU3hcdzWCKejgPafwHwVj0QrJT+sVAKFmJHRTSCNz/d7ryFBoFA0+Dn2V+gstEt28 V7SMu5URgKubGhN+34spJoo6Mt6gyifklzSuFWayowLPcNw3XQ0lE/jar6sqR7pXJ8b5 11fn4D/nMUqW70ziVKdoDah2knIYb9JL6GxdP/VorQO4DSzcQOmqMKZhm+9Ffyk9Gjxj PlVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FiOQD6venFBWNf0Z4AQ/wrw3IlSiEPKwiV4MlNJJ/3s=; b=h+Qb5hpzV8zweFPsDTwmdex+w1ZkbAmEb44rY77B0VN72c8SBh7p1tdbhQeIbChECR TPXnEEVG4y+0YEWBs7UDqETzH38Xuji1r4DFxrlnSjP39LtKnMNVe8RMtaOAtkrWJ7me Y9niFkm5oV4unU9F/qkHvyAHwSdlH0oXndoHLw62jbCo0Uxo93LRp9sb6bRWLuKnHFyb 7bBBk4cB7SFbBTv/eEZd14mIJDelMnicC8bGWIStMTlHF8fW6A9I0tm0XLTGXZj1qa+e R/xkTO/kdpTAHPLNBNJtU5BmjqD1ko7y25h2RC0jZFCA0IietaB1zZiJJnOUp25uuSg+ UfuA== X-Gm-Message-State: AO0yUKVczAtWwO82cq8SgrJ0yLDxMLdcXT9u5IvOVmGIor+VYgqv6CyJ AhhHMrJ0W9YbdCPTGg0+IL4kyXBW1rg= X-Google-Smtp-Source: AK7set99dxabQkO8bhQ9TNf+zy46ecnrIxC4c+0L9/7RqNWaX1x3yGiHbn7CccOiYArBvLYiJ7ZxCA== X-Received: by 2002:a05:6a21:869d:b0:cb:fe3e:e33 with SMTP id ox29-20020a056a21869d00b000cbfe3e0e33mr10467848pzb.42.1677401518050; Sun, 26 Feb 2023 00:51:58 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.51.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:51:57 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 02/10] bpf: Refactor process_dynptr_func Date: Sun, 26 Feb 2023 00:51:12 -0800 Message-Id: <20230226085120.3907863-3-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This change cleans up process_dynptr_func's flow to be more intuitive and updates some comments with more context. Signed-off-by: Joanne Koong --- include/linux/bpf_verifier.h | 3 -- kernel/bpf/verifier.c | 58 ++++++++++++++++++------------------ 2 files changed, 29 insertions(+), 32 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index cf1bb1cf4a7b..b26ff2a8f63b 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -616,9 +616,6 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, enum bpf_arg_type arg_type); int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno, u32 mem_size); -struct bpf_call_arg_meta; -int process_dynptr_func(struct bpf_verifier_env *env, int regno, - enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta); /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */ static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5cb8b623f639..baecccc5fa7a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -959,39 +959,49 @@ static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env, return 0; } -static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg, - int spi) +static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg) { + int spi; + if (reg->type == CONST_PTR_TO_DYNPTR) return false; - /* For -ERANGE (i.e. spi not falling into allocated stack slots), we - * will do check_mem_access to check and update stack bounds later, so - * return true for that case. + spi = dynptr_get_spi(env, reg); + + /* -ERANGE (i.e. spi not falling into allocated stack slots) isn't an + * error because this just means the stack state hasn't been updated yet. + * We will do check_mem_access to check and update stack bounds later. */ - if (spi < 0) - return spi == -ERANGE; - /* We allow overwriting existing unreferenced STACK_DYNPTR slots, see - * mark_stack_slots_dynptr which calls destroy_if_dynptr_stack_slot to - * ensure dynptr objects at the slots we are touching are completely - * destructed before we reinitialize them for a new one. For referenced - * ones, destroy_if_dynptr_stack_slot returns an error early instead of - * delaying it until the end where the user will get "Unreleased + if (spi < 0 && spi != -ERANGE) + return false; + + /* We don't need to check if the stack slots are marked by previous + * dynptr initializations because we allow overwriting existing unreferenced + * STACK_DYNPTR slots, see mark_stack_slots_dynptr which calls + * destroy_if_dynptr_stack_slot to ensure dynptr objects at the slots we are + * touching are completely destructed before we reinitialize them for a new + * one. For referenced ones, destroy_if_dynptr_stack_slot returns an error early + * instead of delaying it until the end where the user will get "Unreleased * reference" error. */ return true; } -static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg, - int spi) +static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg) { struct bpf_func_state *state = func(env, reg); - int i; + int i, spi; - /* This already represents first slot of initialized bpf_dynptr */ + /* This already represents first slot of initialized bpf_dynptr. + * + * CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to + * check_func_arg_reg_off's logic, so we don't need to check its + * offset and alignment. + */ if (reg->type == CONST_PTR_TO_DYNPTR) return true; + spi = dynptr_get_spi(env, reg); if (spi < 0) return false; if (!state->stack[spi].spilled_ptr.dynptr.first_slot) @@ -6219,7 +6229,6 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; - int spi = 0; /* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*): @@ -6228,15 +6237,6 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n"); return -EFAULT; } - /* CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to - * check_func_arg_reg_off's logic. We only need to check offset - * and its alignment for PTR_TO_STACK. - */ - if (reg->type == PTR_TO_STACK) { - spi = dynptr_get_spi(env, reg); - if (spi < 0 && spi != -ERANGE) - return spi; - } /* MEM_UNINIT - Points to memory that is an appropriate candidate for * constructing a mutable bpf_dynptr object. @@ -6254,7 +6254,7 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, * to. */ if (arg_type & MEM_UNINIT) { - if (!is_dynptr_reg_valid_uninit(env, reg, spi)) { + if (!is_dynptr_reg_valid_uninit(env, reg)) { verbose(env, "Dynptr has to be an uninitialized dynptr\n"); return -EINVAL; } @@ -6277,7 +6277,7 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, return -EINVAL; } - if (!is_dynptr_reg_valid_init(env, reg, spi)) { + if (!is_dynptr_reg_valid_init(env, reg)) { verbose(env, "Expected an initialized dynptr as arg #%d\n", regno); From patchwork Sun Feb 26 08:51:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152333 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2898CC64ED6 for ; Sun, 26 Feb 2023 08:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229547AbjBZIwL (ORCPT ); Sun, 26 Feb 2023 03:52:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbjBZIwK (ORCPT ); Sun, 26 Feb 2023 03:52:10 -0500 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADE981164F; Sun, 26 Feb 2023 00:52:04 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id bh1so3757651plb.11; Sun, 26 Feb 2023 00:52:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=IKaUlnn2p2n/YpKv4dB99mACnWsj1C93P960OCd+CGg=; b=c8OLEX6zhFx8RoYu6W9pNBAX0EFQMEn2oa2V82GmrJTjDmt0pRQoPDBhQkbH1R0Atn Niznka8WOXKh5CpP5YqBpRTOIIF4fWdmLJB917FbVLLNmlKVPJj50tossBmc8g3q7xop ZiKd4OeP5hhLhUKp8RffuG2gu6FV10Bwoo0vcPJbFXmqeymCEGeZuSVyBnhfCY/4ZByl UydSPzUPovOP39HsmRBPjeHYRL9C0P3GJMHVmToL+mgOr6cEYt2rcq7jqedx9q2mnnEq m0ICKnBAvzOKiPs4h0YUW55G8CIT9iHuMBNRgnL3H6ZhJGCpf4ZMPrn5GjA+2nYB3h5E rsSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=IKaUlnn2p2n/YpKv4dB99mACnWsj1C93P960OCd+CGg=; b=hi4fJjSV4tJSoCoNd1PFTtREg0+By0vzUSvmtuNaJv0wsb5fCPEoyv1Qkn9JvIj+N4 mQgSfVrSqEOVMS12wiCv1za0y7lzpMjmvwb1wNefMZ8CXIDcQPFKWUYRcscD/nNL2+02 RmxxOMPXCjq9izxEgvYluFoAxy4ocngh26pHLE7qRc2nr/aE2dLTseYpcMBBJO7/MhDH jCS88Gi29wp1D20pRjwx+DS+PyuDinHKWojW7S9ri/peN5yF32CN+uYY831cF/wWHGgL EOQubJGkzEGhtvHzf2l2N4zXCRy4wWvCCBnhmoFCG3TG369VZC+A2TSWzWKALEvdMKH6 C/AQ== X-Gm-Message-State: AO0yUKXKyAx9xfisEmAWZbnync9RQ6OGMC34STlnFhdEUmvI8SQyy5p9 Jb/0uobzVn05rpqDA1h+blwjkzQdX9k= X-Google-Smtp-Source: AK7set8U2i/LBCnO7xn2TsQAaVx/9AvCErqIzBuB/HryS9+V5o99fqwnPsXU5JV44CRVqic9gaCcnA== X-Received: by 2002:a05:6a20:8356:b0:cc:5ad3:4804 with SMTP id z22-20020a056a20835600b000cc5ad34804mr7047306pzc.28.1677401523840; Sun, 26 Feb 2023 00:52:03 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:03 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 03/10] bpf: Allow initializing dynptrs in kfuncs Date: Sun, 26 Feb 2023 00:51:13 -0800 Message-Id: <20230226085120.3907863-4-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This change allows kfuncs to take in an uninitialized dynptr as a parameter. Before this change, only helper functions could successfully use uninitialized dynptrs. This change moves the memory access check (including stack state growing and slot marking) into process_dynptr_func(), which both helpers and kfuncs call into. Signed-off-by: Joanne Koong --- kernel/bpf/verifier.c | 67 ++++++++++++++----------------------------- 1 file changed, 22 insertions(+), 45 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index baecccc5fa7a..a4cca21aefc3 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -268,7 +268,6 @@ struct bpf_call_arg_meta { u32 ret_btf_id; u32 subprogno; struct btf_field *kptr_field; - u8 uninit_dynptr_regno; }; struct btf *btf_vmlinux; @@ -6225,10 +6224,11 @@ static int process_kptr_func(struct bpf_verifier_env *env, int regno, * Helpers which do not mutate the bpf_dynptr set MEM_RDONLY in their argument * type, and declare it as 'const struct bpf_dynptr *' in their prototype. */ -int process_dynptr_func(struct bpf_verifier_env *env, int regno, - enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta) +int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx, + enum bpf_arg_type arg_type) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; + int err; /* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*): @@ -6254,23 +6254,23 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, * to. */ if (arg_type & MEM_UNINIT) { + int i; + if (!is_dynptr_reg_valid_uninit(env, reg)) { verbose(env, "Dynptr has to be an uninitialized dynptr\n"); return -EINVAL; } - /* We only support one dynptr being uninitialized at the moment, - * which is sufficient for the helper functions we have right now. - */ - if (meta->uninit_dynptr_regno) { - verbose(env, "verifier internal error: multiple uninitialized dynptr args\n"); - return -EFAULT; + /* we write BPF_DW bits (8 bytes) at a time */ + for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) { + err = check_mem_access(env, insn_idx, regno, + i, BPF_DW, BPF_WRITE, -1, false); + if (err) + return err; } - meta->uninit_dynptr_regno = regno; + err = mark_stack_slots_dynptr(env, reg, arg_type, insn_idx); } else /* MEM_RDONLY and None case from above */ { - int err; - /* For the reg->type == PTR_TO_STACK case, bpf_dynptr is never const */ if (reg->type == CONST_PTR_TO_DYNPTR && !(arg_type & MEM_RDONLY)) { verbose(env, "cannot pass pointer to const bpf_dynptr, the helper mutates it\n"); @@ -6306,10 +6306,8 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, } err = mark_dynptr_read(env, reg); - if (err) - return err; } - return 0; + return err; } static bool arg_type_is_mem_size(enum bpf_arg_type type) @@ -6719,7 +6717,8 @@ static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state static int check_func_arg(struct bpf_verifier_env *env, u32 arg, struct bpf_call_arg_meta *meta, - const struct bpf_func_proto *fn) + const struct bpf_func_proto *fn, + int insn_idx) { u32 regno = BPF_REG_1 + arg; struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; @@ -6932,7 +6931,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, err = check_mem_size_reg(env, reg, regno, true, meta); break; case ARG_PTR_TO_DYNPTR: - err = process_dynptr_func(env, regno, arg_type, meta); + err = process_dynptr_func(env, regno, insn_idx, arg_type); if (err) return err; break; @@ -8218,7 +8217,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn meta.func_id = func_id; /* check args */ for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) { - err = check_func_arg(env, i, &meta, fn); + err = check_func_arg(env, i, &meta, fn, insn_idx); if (err) return err; } @@ -8243,30 +8242,6 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn regs = cur_regs(env); - /* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot - * be reinitialized by any dynptr helper. Hence, mark_stack_slots_dynptr - * is safe to do directly. - */ - if (meta.uninit_dynptr_regno) { - if (regs[meta.uninit_dynptr_regno].type == CONST_PTR_TO_DYNPTR) { - verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be initialized\n"); - return -EFAULT; - } - /* we write BPF_DW bits (8 bytes) at a time */ - for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) { - err = check_mem_access(env, insn_idx, meta.uninit_dynptr_regno, - i, BPF_DW, BPF_WRITE, -1, false); - if (err) - return err; - } - - err = mark_stack_slots_dynptr(env, ®s[meta.uninit_dynptr_regno], - fn->arg_type[meta.uninit_dynptr_regno - BPF_REG_1], - insn_idx); - if (err) - return err; - } - if (meta.release_regno) { err = -EINVAL; /* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot @@ -9475,7 +9450,8 @@ static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env, &meta->arg_rbtree_root.field); } -static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta) +static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, + int insn_idx) { const char *func_name = meta->func_name, *ref_tname; const struct btf *btf = meta->btf; @@ -9672,7 +9648,8 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return -EINVAL; } - ret = process_dynptr_func(env, regno, ARG_PTR_TO_DYNPTR | MEM_RDONLY, NULL); + ret = process_dynptr_func(env, regno, insn_idx, + ARG_PTR_TO_DYNPTR | MEM_RDONLY); if (ret < 0) return ret; break; @@ -9880,7 +9857,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, } /* Check the arguments */ - err = check_kfunc_args(env, &meta); + err = check_kfunc_args(env, &meta, insn_idx); if (err < 0) return err; /* In case of release function, we get register number of refcounted From patchwork Sun Feb 26 08:51:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152334 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAFCFC7EE2E for ; Sun, 26 Feb 2023 08:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229507AbjBZIwM (ORCPT ); Sun, 26 Feb 2023 03:52:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229557AbjBZIwK (ORCPT ); Sun, 26 Feb 2023 03:52:10 -0500 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C828611665; Sun, 26 Feb 2023 00:52:06 -0800 (PST) Received: by mail-pj1-x102a.google.com with SMTP id u10so3162870pjc.5; Sun, 26 Feb 2023 00:52:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=I4DPxaA2KI42WAf76J1TanSD7CSM/V5DVF96yv7d/wc=; b=PC3wWSXji3vHKoI700y7qX3wzD5w99OjEiqnCW7njziy/uBcwtrx+ahMmyGrAjxG/T W08aTdMtRq+ZRCT41KR0KAGKgJnoEn6+3jWgmmjNb45tJBiIfcM43xxf4P4WFH0kw5m/ jYs28v0NiQ52bXkq7UHMEKNKWzuLXNMgNX/2I2v0/4/8kE7Sd9r+pW7jSZ2/Qd+UGBZU 5Q41u9CqveHCwUOwFAj1XrIvMfAC3Z+EZsg8Yc0f95IHJogQGEYZtzrmH2Hjy/D41ap5 jVHHz3VU1OVx+desJb1hXX34Io3g9QnsnnqBBdRPNuHzSwSukc98BxIUuzrO+sAfIMLx iSBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=I4DPxaA2KI42WAf76J1TanSD7CSM/V5DVF96yv7d/wc=; b=hbnGC8J96QzthSXH5YYrjTZ9TlOm0pz+6ug7hQ/nNhQZK9zpvGlzSen2IGcMZ+9u1k hn1x66ow6JeqdgIEMmAiVEsCvUjF3F/K5no5AOIYjoijli+J1FpBL5nELHh0yhv8sVLM fbLFK7zi5qRaEClsgaYD2ewVqBAFBDhUt2asbvN2RblQj5Jwml3H9vhx5BGnH+5RHWfx gl0xgk3H1DscdwD0mI6g1ZAaETTyAEf9uYb6iVbZ6Uaysk7B1NZ+NoXjUTYoM+XHulJ9 O3jR2UqSLL1rvOEcB35QAhMUGVPYnCZWTLh7MdNAGlb7lUQaj/LLGXK8QlxDx2hl8Wyf cWeQ== X-Gm-Message-State: AO0yUKW5e2/djcqsBB5+IB1fNbjXwzfAA6kQB5TPnSMbOZXhav4sF15I qxj6HI5z82y65NvLzpgWt9B1dN/IMFE= X-Google-Smtp-Source: AK7set9j5RvnmvyC9b7uiZmSEVofrVWY2pwxDayUI12artA1DXaGwlezSBRnfybxsayqet68Tw9Piw== X-Received: by 2002:a05:6a20:32aa:b0:cc:1014:1fb4 with SMTP id g42-20020a056a2032aa00b000cc10141fb4mr9062053pzd.22.1677401525974; Sun, 26 Feb 2023 00:52:05 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:05 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 04/10] bpf: Define no-ops for externally called bpf dynptr functions Date: Sun, 26 Feb 2023 00:51:14 -0800 Message-Id: <20230226085120.3907863-5-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Some bpf dynptr functions will be called from places where if CONFIG_BPF_SYSCALL is not set, then the dynptr function is undefined. For example, when skb type dynptrs are added in the next commit, dynptr functions are called from net/core/filter.c This patch defines no-op implementations of these dynptr functions so that they do not break compilation by being an undefined reference. Signed-off-by: Joanne Koong --- include/linux/bpf.h | 75 +++++++++++++++++++++++++++------------------ 1 file changed, 45 insertions(+), 30 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 520b238abd5a..296841a31749 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1124,6 +1124,33 @@ static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func( return bpf_func(ctx, insnsi); } +/* the implementation of the opaque uapi struct bpf_dynptr */ +struct bpf_dynptr_kern { + void *data; + /* Size represents the number of usable bytes of dynptr data. + * If for example the offset is at 4 for a local dynptr whose data is + * of type u64, the number of usable bytes is 4. + * + * The upper 8 bits are reserved. It is as follows: + * Bits 0 - 23 = size + * Bits 24 - 30 = dynptr type + * Bit 31 = whether dynptr is read-only + */ + u32 size; + u32 offset; +} __aligned(8); + +enum bpf_dynptr_type { + BPF_DYNPTR_TYPE_INVALID, + /* Points to memory that is local to the bpf program */ + BPF_DYNPTR_TYPE_LOCAL, + /* Underlying data is a ringbuf record */ + BPF_DYNPTR_TYPE_RINGBUF, +}; + +int bpf_dynptr_check_size(u32 size); +u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr); + #ifdef CONFIG_BPF_JIT int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); @@ -2266,6 +2293,11 @@ static inline bool has_current_bpf_ctx(void) } void notrace bpf_prog_inc_misses_counter(struct bpf_prog *prog); + +void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data, + enum bpf_dynptr_type type, u32 offset, u32 size); +void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr); +void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr); #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) { @@ -2495,6 +2527,19 @@ static inline void bpf_prog_inc_misses_counter(struct bpf_prog *prog) static inline void bpf_cgrp_storage_free(struct cgroup *cgroup) { } + +static inline void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data, + enum bpf_dynptr_type type, u32 offset, u32 size) +{ +} + +static inline void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr) +{ +} + +static inline void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr) +{ +} #endif /* CONFIG_BPF_SYSCALL */ void __bpf_free_used_btfs(struct bpf_prog_aux *aux, @@ -2913,36 +2958,6 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, u32 num_args, struct bpf_bprintf_data *data); void bpf_bprintf_cleanup(struct bpf_bprintf_data *data); -/* the implementation of the opaque uapi struct bpf_dynptr */ -struct bpf_dynptr_kern { - void *data; - /* Size represents the number of usable bytes of dynptr data. - * If for example the offset is at 4 for a local dynptr whose data is - * of type u64, the number of usable bytes is 4. - * - * The upper 8 bits are reserved. It is as follows: - * Bits 0 - 23 = size - * Bits 24 - 30 = dynptr type - * Bit 31 = whether dynptr is read-only - */ - u32 size; - u32 offset; -} __aligned(8); - -enum bpf_dynptr_type { - BPF_DYNPTR_TYPE_INVALID, - /* Points to memory that is local to the bpf program */ - BPF_DYNPTR_TYPE_LOCAL, - /* Underlying data is a kernel-produced ringbuf record */ - BPF_DYNPTR_TYPE_RINGBUF, -}; - -void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data, - enum bpf_dynptr_type type, u32 offset, u32 size); -void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr); -int bpf_dynptr_check_size(u32 size); -u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr); - #ifdef CONFIG_BPF_LSM void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype); void bpf_cgroup_atype_put(int cgroup_atype); From patchwork Sun Feb 26 08:51:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152335 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BCD8C7EE2F for ; Sun, 26 Feb 2023 08:52:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229556AbjBZIwM (ORCPT ); Sun, 26 Feb 2023 03:52:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229562AbjBZIwK (ORCPT ); Sun, 26 Feb 2023 03:52:10 -0500 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34C6713DC4; Sun, 26 Feb 2023 00:52:08 -0800 (PST) Received: by mail-pg1-x531.google.com with SMTP id bn17so1876286pgb.10; Sun, 26 Feb 2023 00:52:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=7xc259GjUZKykJMU7oKtUYVSPSoBfPnEWYraBTaL9Ag=; b=cHl0KB/AGBGjY7M77CIvVjgWq1LBtJo2Rl11bDuc2TW7KSrz12FzEAjIvhEba4x2HE ZpWzZrwDokvS0ORv4O1iH5Mqe8VapmX7j/kuex+4V6tDjjWImb4wS44n6plyWKAvbmBw rr3+IYI18yZg/D4qXFWrD1QwAq6JrulqFB8yvJzb8bhWalNcC9S/uLwEja/pV4C2egYb ZJE/Lk0mX8DSrUdVNQQ6wC5nJEgpGgrCUnk5mUzLTT75TKEfxuxnQOa+2HeC+XRrh4qD 5PbTGEr5npAjaxo46dy9+i0PFTl2u1Gy1Tb+2to5O99STIUfozsSMpMUz/qSK2TV1Isi mulA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=7xc259GjUZKykJMU7oKtUYVSPSoBfPnEWYraBTaL9Ag=; b=HvODBEtg/OyYLV+619VdH3i1IlxaNj4VwJR8aYtqH4sirWlKMAfJ/+ELeLp3TAKp+V jr8HNSBu02cn8tx3ZsYckXGKDVFKROBBqiPQ1IPV7gMDQy37ObBXZNGJ37sAe3vTjYOt KSoMIHlR32BhLzTr/miBHX7ZZC8AQGHsOd4CXvJdIsz7hCU19hWXeLNyv865DajuKzXd Iw2llbJF6f0CtvoLmU8yLynDnHUyO/RqMflgIqvbuyLf1x9DWON33kOokynBHxSfL5kF O35hZcDKoiClpwGxwNj8Tp6/H0I6dH34QVyageDO0o4qXP0m9Fs0UQ6GcsmYxu5eVuWB q2NQ== X-Gm-Message-State: AO0yUKWpb/+VeafDeWJFN9uIWr1j2SoSeH6yawckWYPfoGIuQFA0Zg5f pECvEcrAKITbfQ61FSiURQz8dAqOAt4= X-Google-Smtp-Source: AK7set8S03mcth1Tu96Rz1I/lJacNXJ8ETIU+BpvU0Qvz9ek2mte3nCYF9RD5GNzCtgeb/KYSqr3Pg== X-Received: by 2002:aa7:9681:0:b0:5a8:abd7:a9e8 with SMTP id f1-20020aa79681000000b005a8abd7a9e8mr18034797pfk.27.1677401527287; Sun, 26 Feb 2023 00:52:07 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:06 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 05/10] bpf: Refactor verifier dynptr into get_dynptr_arg_reg Date: Sun, 26 Feb 2023 00:51:15 -0800 Message-Id: <20230226085120.3907863-6-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This commit refactors the logic for determining which register in a function is the dynptr into "get_dynptr_arg_reg". This will be used in the future when the dynptr reg for BPF_FUNC_dynptr_write will need to be obtained in order to support writes for skb dynptrs. Signed-off-by: Joanne Koong --- kernel/bpf/verifier.c | 80 +++++++++++++++++++++++++++---------------- 1 file changed, 50 insertions(+), 30 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a4cca21aefc3..cedd38292a62 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6689,6 +6689,28 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env, } } +static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env, + const struct bpf_func_proto *fn, + struct bpf_reg_state *regs) +{ + struct bpf_reg_state *state = NULL; + int i; + + for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) + if (arg_type_is_dynptr(fn->arg_type[i])) { + if (state) { + verbose(env, "verifier internal error: multiple dynptr args\n"); + return NULL; + } + state = ®s[BPF_REG_1 + i]; + } + + if (!state) + verbose(env, "verifier internal error: no dynptr arg found\n"); + + return state; +} + static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg) { struct bpf_func_state *state = func(env, reg); @@ -8326,43 +8348,41 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn } break; case BPF_FUNC_dynptr_data: - for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) { - if (arg_type_is_dynptr(fn->arg_type[i])) { - struct bpf_reg_state *reg = ®s[BPF_REG_1 + i]; - int id, ref_obj_id; - - if (meta.dynptr_id) { - verbose(env, "verifier internal error: meta.dynptr_id already set\n"); - return -EFAULT; - } - - if (meta.ref_obj_id) { - verbose(env, "verifier internal error: meta.ref_obj_id already set\n"); - return -EFAULT; - } + { + struct bpf_reg_state *reg; + int id, ref_obj_id; - id = dynptr_id(env, reg); - if (id < 0) { - verbose(env, "verifier internal error: failed to obtain dynptr id\n"); - return id; - } + reg = get_dynptr_arg_reg(env, fn, regs); + if (!reg) + return -EFAULT; - ref_obj_id = dynptr_ref_obj_id(env, reg); - if (ref_obj_id < 0) { - verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n"); - return ref_obj_id; - } - meta.dynptr_id = id; - meta.ref_obj_id = ref_obj_id; - break; - } + if (meta.dynptr_id) { + verbose(env, "verifier internal error: meta.dynptr_id already set\n"); + return -EFAULT; } - if (i == MAX_BPF_FUNC_REG_ARGS) { - verbose(env, "verifier internal error: no dynptr in bpf_dynptr_data()\n"); + if (meta.ref_obj_id) { + verbose(env, "verifier internal error: meta.ref_obj_id already set\n"); return -EFAULT; } + + id = dynptr_id(env, reg); + if (id < 0) { + verbose(env, "verifier internal error: failed to obtain dynptr id\n"); + return id; + } + + ref_obj_id = dynptr_ref_obj_id(env, reg); + if (ref_obj_id < 0) { + verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n"); + return ref_obj_id; + } + + meta.dynptr_id = id; + meta.ref_obj_id = ref_obj_id; + break; + } case BPF_FUNC_user_ringbuf_drain: err = __check_func_call(env, insn, insn_idx_p, meta.subprogno, set_user_ringbuf_callback_state); From patchwork Sun Feb 26 08:51:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152336 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98369C6FA8E for ; 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[75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:08 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 06/10] bpf: Add __uninit kfunc annotation Date: Sun, 26 Feb 2023 00:51:16 -0800 Message-Id: <20230226085120.3907863-7-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This patch adds __uninit as a kfunc annotation. This will be useful for scenarios such as for example in dynptrs, indicating whether the dynptr should be checked by the verifier as an initialized or an uninitialized dynptr. Without this annotation, the alternative would be needing to hard-code in the verifier the specific kfunc to indicate that arg should be treated as an uninitialized arg. Signed-off-by: Joanne Koong --- Documentation/bpf/kfuncs.rst | 17 +++++++++++++++++ kernel/bpf/verifier.c | 18 ++++++++++++++++-- 2 files changed, 33 insertions(+), 2 deletions(-) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 226313747be5..9a78533d25ac 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -100,6 +100,23 @@ Hence, whenever a constant scalar argument is accepted by a kfunc which is not a size parameter, and the value of the constant matters for program safety, __k suffix should be used. +2.2.2 __uninit Annotation +-------------------- + +This annotation is used to indicate that the argument will be treated as +uninitialized. + +An example is given below:: + + __bpf_kfunc int bpf_dynptr_from_skb(..., struct bpf_dynptr_kern *ptr__uninit) + { + ... + } + +Here, the dynptr will be treated as an uninitialized dynptr. Without this +annotation, the verifier will reject the program if the dynptr passed in is +not initialized. + .. _BPF_kfunc_nodef: 2.3 Using an existing kernel function diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cedd38292a62..3a7f69b29053 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8727,6 +8727,11 @@ static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param return __kfunc_param_match_suffix(btf, arg, "__alloc"); } +static bool is_kfunc_arg_uninit(const struct btf *btf, const struct btf_param *arg) +{ + return __kfunc_param_match_suffix(btf, arg, "__uninit"); +} + static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, const struct btf_param *arg, const char *name) @@ -9662,17 +9667,26 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return ret; break; case KF_ARG_PTR_TO_DYNPTR: + { + enum bpf_arg_type dynptr_arg_type = ARG_PTR_TO_DYNPTR; + if (reg->type != PTR_TO_STACK && reg->type != CONST_PTR_TO_DYNPTR) { verbose(env, "arg#%d expected pointer to stack or dynptr_ptr\n", i); return -EINVAL; } - ret = process_dynptr_func(env, regno, insn_idx, - ARG_PTR_TO_DYNPTR | MEM_RDONLY); + if (reg->type == CONST_PTR_TO_DYNPTR) + dynptr_arg_type |= MEM_RDONLY; + + if (is_kfunc_arg_uninit(btf, &args[i])) + dynptr_arg_type |= MEM_UNINIT; + + ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type); if (ret < 0) return ret; break; + } case KF_ARG_PTR_TO_LIST_HEAD: if (reg->type != PTR_TO_MAP_VALUE && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { From patchwork Sun Feb 26 08:51:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152337 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC010C64ED6 for ; Sun, 26 Feb 2023 08:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229606AbjBZIw2 (ORCPT ); Sun, 26 Feb 2023 03:52:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229585AbjBZIw0 (ORCPT ); Sun, 26 Feb 2023 03:52:26 -0500 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48517113FE; Sun, 26 Feb 2023 00:52:11 -0800 (PST) Received: by mail-pf1-x434.google.com with SMTP id fd25so1840610pfb.1; Sun, 26 Feb 2023 00:52:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=52o5xOJpDnxF18a8dnrnlktDs+mKjtH68NvHREbNkCE=; b=mvownvjlHRusIZIon1qr4lycdjG7ll4jBFc2/Xim5Wb2HArJdaV31GSnukJ97OMRpc oom+NA3+2G/KcIhqX95d3GSXf4x27S+ZpCo1KK17px6SRxOo5Mxox5vvpFDxTagki9TN 9UJFNJViOhRvRgaSYs+64MlhsX5Hzqz9HRENjqc7r3a/CWw52UqGiKtJX21Ejecp7B7p 4BOLbSteZh77qOI6EObZV0SuvqcJ3nzGfKde+GzMmahIV2DA/4TjEstSsMeoGZWxuq1/ SxNLrx3rpCbFuk3h76MsvwV0Ih+61UEXWvZM3GMQyWJuhWdGW7XgIXSRT0EfnyaQ6qkS 33Xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=52o5xOJpDnxF18a8dnrnlktDs+mKjtH68NvHREbNkCE=; b=7ab1n9YdaOai6Uo5Fv+MVftG3mBnB0/K01rMcMr4ec+guU8XR14MAfiSLKjghwzhwi 4tUEYL7oJkXcvEFWROg6CGt4iTlt43Rpf9F5yow6Zs7TUMmuGTsi3FW0xMekflZ3wtLL ynkaVms+UGz7AimBYpETAW71/tLdrMFeTf9F8zcv14+zExiYnY/jUOiMtTprzd+4rsGT DNfxYcfZja71EHyiOiZ5at1NjMMEWLJeyc+LldzZmBebhbKLgj6pZ6eTzgQA6PbAUdRs 7p4jMq8skXylbJypmZN5C5On5yrtWl+cRwz8G3vBE27+WTBgXKCbsg9PVUwUHihIEBJY zBiQ== X-Gm-Message-State: AO0yUKXkbJ7yup8QWcikJKxP4tstmfYnn+aFiE+9GqEsD+g+zb7CM7U4 +84lAUWGmSBagv4SXY5oBxmGKoNd60k= X-Google-Smtp-Source: AK7set8Fimu3zOoopSBJUzLP3DN0+ZnN3fIl07RbNeiRJc5l2+WVVl3oJiN2ntotS7ZNSR+fg6uWYg== X-Received: by 2002:a62:505:0:b0:5a8:d97d:c346 with SMTP id 5-20020a620505000000b005a8d97dc346mr18366477pff.12.1677401529935; Sun, 26 Feb 2023 00:52:09 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:09 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 07/10] bpf: Add skb dynptrs Date: Sun, 26 Feb 2023 00:51:17 -0800 Message-Id: <20230226085120.3907863-8-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add skb dynptrs, which are dynptrs whose underlying pointer points to a skb. The dynptr acts on skb data. skb dynptrs have two main benefits. One is that they allow operations on sizes that are not statically known at compile-time (eg variable-sized accesses). Another is that parsing the packet data through dynptrs (instead of through direct access of skb->data and skb->data_end) can be more ergonomic and less brittle (eg does not need manual if checking for being within bounds of data_end). For bpf prog types that don't support writes on skb data, the dynptr is read-only (bpf_dynptr_write() will return an error) For reads and writes through the bpf_dynptr_read() and bpf_dynptr_write() interfaces, reading and writing from/to data in the head as well as from/to non-linear paged buffers is supported. Data slices through the bpf_dynptr_data API are not supported; instead bpf_dynptr_slice() and bpf_dynptr_slice_rdwr() (added in subsequent commit) should be used. For examples of how skb dynptrs can be used, please see the attached selftests. Signed-off-by: Joanne Koong --- include/linux/bpf.h | 14 ++++++- include/linux/filter.h | 18 ++++++++ include/uapi/linux/bpf.h | 13 +++++- kernel/bpf/btf.c | 18 ++++++++ kernel/bpf/helpers.c | 76 +++++++++++++++++++++++++++------- kernel/bpf/verifier.c | 61 +++++++++++++++++++++++++++ net/core/filter.c | 67 ++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 13 +++++- 8 files changed, 261 insertions(+), 19 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 296841a31749..e7436d7615b0 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -607,11 +607,14 @@ enum bpf_type_flag { */ NON_OWN_REF = BIT(14 + BPF_BASE_TYPE_BITS), + /* DYNPTR points to sk_buff */ + DYNPTR_TYPE_SKB = BIT(15 + BPF_BASE_TYPE_BITS), + __BPF_TYPE_FLAG_MAX, __BPF_TYPE_LAST_FLAG = __BPF_TYPE_FLAG_MAX - 1, }; -#define DYNPTR_TYPE_FLAG_MASK (DYNPTR_TYPE_LOCAL | DYNPTR_TYPE_RINGBUF) +#define DYNPTR_TYPE_FLAG_MASK (DYNPTR_TYPE_LOCAL | DYNPTR_TYPE_RINGBUF | DYNPTR_TYPE_SKB) /* Max number of base types. */ #define BPF_BASE_TYPE_LIMIT (1UL << BPF_BASE_TYPE_BITS) @@ -1146,6 +1149,8 @@ enum bpf_dynptr_type { BPF_DYNPTR_TYPE_LOCAL, /* Underlying data is a ringbuf record */ BPF_DYNPTR_TYPE_RINGBUF, + /* Underlying data is a sk_buff */ + BPF_DYNPTR_TYPE_SKB, }; int bpf_dynptr_check_size(u32 size); @@ -2846,6 +2851,8 @@ u32 bpf_sock_convert_ctx_access(enum bpf_access_type type, struct bpf_insn *insn_buf, struct bpf_prog *prog, u32 *target_size); +int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, + struct bpf_dynptr_kern *ptr); #else static inline bool bpf_sock_common_is_valid_access(int off, int size, enum bpf_access_type type, @@ -2867,6 +2874,11 @@ static inline u32 bpf_sock_convert_ctx_access(enum bpf_access_type type, { return 0; } +static inline int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, + struct bpf_dynptr_kern *ptr) +{ + return -EOPNOTSUPP; +} #endif #ifdef CONFIG_INET diff --git a/include/linux/filter.h b/include/linux/filter.h index 1727898f1641..de18e844d15e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1542,4 +1542,22 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u64 index return XDP_REDIRECT; } +#ifdef CONFIG_NET +int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len); +int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, + u32 len, u64 flags); +#else /* CONFIG_NET */ +static inline int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, + void *to, u32 len) +{ + return -EOPNOTSUPP; +} + +static inline int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, + const void *from, u32 len, u64 flags) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_NET */ + #endif /* __LINUX_FILTER_H__ */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 62ce1f5d1b1d..d0351d30e551 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5325,11 +5325,17 @@ union bpf_attr { * Description * Write *len* bytes from *src* into *dst*, starting from *offset* * into *dst*. - * *flags* is currently unused. + * + * *flags* must be 0 except for skb-type dynptrs. + * + * For skb-type dynptrs: + * * For *flags*, please see the flags accepted by + * **bpf_skb_store_bytes**\ (). * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length * of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst* - * is a read-only dynptr or if *flags* is not 0. + * is a read-only dynptr or if *flags* is not correct. For skb-type dynptrs, + * other errors correspond to errors returned by **bpf_skb_store_bytes**\ (). * * void *bpf_dynptr_data(const struct bpf_dynptr *ptr, u32 offset, u32 len) * Description @@ -5337,6 +5343,9 @@ union bpf_attr { * * *len* must be a statically known value. The returned data slice * is invalidated whenever the dynptr is invalidated. + * + * skb type dynptrs may not use bpf_dynptr_data. They should + * instead use bpf_dynptr_slice and bpf_dynptr_slice_rdwr. * Return * Pointer to the underlying dynptr data, NULL if the dynptr is * read-only, if the dynptr is invalid, or if the offset and length diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 84cca8473873..ef2d8969ed1f 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -207,6 +207,11 @@ enum btf_kfunc_hook { BTF_KFUNC_HOOK_TRACING, BTF_KFUNC_HOOK_SYSCALL, BTF_KFUNC_HOOK_FMODRET, + BTF_KFUNC_HOOK_CGROUP_SKB, + BTF_KFUNC_HOOK_SCHED_ACT, + BTF_KFUNC_HOOK_SK_SKB, + BTF_KFUNC_HOOK_SOCKET_FILTER, + BTF_KFUNC_HOOK_LWT, BTF_KFUNC_HOOK_MAX, }; @@ -7708,6 +7713,19 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) return BTF_KFUNC_HOOK_TRACING; case BPF_PROG_TYPE_SYSCALL: return BTF_KFUNC_HOOK_SYSCALL; + case BPF_PROG_TYPE_CGROUP_SKB: + return BTF_KFUNC_HOOK_CGROUP_SKB; + case BPF_PROG_TYPE_SCHED_ACT: + return BTF_KFUNC_HOOK_SCHED_ACT; + case BPF_PROG_TYPE_SK_SKB: + return BTF_KFUNC_HOOK_SK_SKB; + case BPF_PROG_TYPE_SOCKET_FILTER: + return BTF_KFUNC_HOOK_SOCKET_FILTER; + case BPF_PROG_TYPE_LWT_OUT: + case BPF_PROG_TYPE_LWT_IN: + case BPF_PROG_TYPE_LWT_XMIT: + case BPF_PROG_TYPE_LWT_SEG6LOCAL: + return BTF_KFUNC_HOOK_LWT; default: return BTF_KFUNC_HOOK_MAX; } diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a784be6f8bac..1863bea0a21f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1420,11 +1420,21 @@ static bool bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr) return ptr->size & DYNPTR_RDONLY_BIT; } +void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr) +{ + ptr->size |= DYNPTR_RDONLY_BIT; +} + static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type) { ptr->size |= type << DYNPTR_TYPE_SHIFT; } +static enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *ptr) +{ + return (ptr->size & ~(DYNPTR_RDONLY_BIT)) >> DYNPTR_TYPE_SHIFT; +} + u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr) { return ptr->size & DYNPTR_SIZE_MASK; @@ -1497,6 +1507,7 @@ static const struct bpf_func_proto bpf_dynptr_from_mem_proto = { BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src, u32, offset, u64, flags) { + enum bpf_dynptr_type type; int err; if (!src->data || flags) @@ -1506,13 +1517,23 @@ BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern if (err) return err; - /* Source and destination may possibly overlap, hence use memmove to - * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr - * pointing to overlapping PTR_TO_MAP_VALUE regions. - */ - memmove(dst, src->data + src->offset + offset, len); + type = bpf_dynptr_get_type(src); - return 0; + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + case BPF_DYNPTR_TYPE_RINGBUF: + /* Source and destination may possibly overlap, hence use memmove to + * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr + * pointing to overlapping PTR_TO_MAP_VALUE regions. + */ + memmove(dst, src->data + src->offset + offset, len); + return 0; + case BPF_DYNPTR_TYPE_SKB: + return __bpf_skb_load_bytes(src->data, src->offset + offset, dst, len); + default: + WARN_ONCE(true, "bpf_dynptr_read: unknown dynptr type %d\n", type); + return -EFAULT; + } } static const struct bpf_func_proto bpf_dynptr_read_proto = { @@ -1529,22 +1550,36 @@ static const struct bpf_func_proto bpf_dynptr_read_proto = { BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src, u32, len, u64, flags) { + enum bpf_dynptr_type type; int err; - if (!dst->data || flags || bpf_dynptr_is_rdonly(dst)) + if (!dst->data || bpf_dynptr_is_rdonly(dst)) return -EINVAL; err = bpf_dynptr_check_off_len(dst, offset, len); if (err) return err; - /* Source and destination may possibly overlap, hence use memmove to - * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr - * pointing to overlapping PTR_TO_MAP_VALUE regions. - */ - memmove(dst->data + dst->offset + offset, src, len); + type = bpf_dynptr_get_type(dst); - return 0; + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + case BPF_DYNPTR_TYPE_RINGBUF: + if (flags) + return -EINVAL; + /* Source and destination may possibly overlap, hence use memmove to + * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr + * pointing to overlapping PTR_TO_MAP_VALUE regions. + */ + memmove(dst->data + dst->offset + offset, src, len); + return 0; + case BPF_DYNPTR_TYPE_SKB: + return __bpf_skb_store_bytes(dst->data, dst->offset + offset, src, len, + flags); + default: + WARN_ONCE(true, "bpf_dynptr_write: unknown dynptr type %d\n", type); + return -EFAULT; + } } static const struct bpf_func_proto bpf_dynptr_write_proto = { @@ -1560,6 +1595,7 @@ static const struct bpf_func_proto bpf_dynptr_write_proto = { BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u32, len) { + enum bpf_dynptr_type type; int err; if (!ptr->data) @@ -1572,7 +1608,19 @@ BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u3 if (bpf_dynptr_is_rdonly(ptr)) return 0; - return (unsigned long)(ptr->data + ptr->offset + offset); + type = bpf_dynptr_get_type(ptr); + + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + case BPF_DYNPTR_TYPE_RINGBUF: + return (unsigned long)(ptr->data + ptr->offset + offset); + case BPF_DYNPTR_TYPE_SKB: + /* skb dynptrs should use bpf_dynptr_slice / bpf_dynptr_slice_rdwr */ + return 0; + default: + WARN_ONCE(true, "bpf_dynptr_data: unknown dynptr type %d\n", type); + return 0; + } } static const struct bpf_func_proto bpf_dynptr_data_proto = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3a7f69b29053..ef38ec52569a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -750,6 +750,8 @@ static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type) return BPF_DYNPTR_TYPE_LOCAL; case DYNPTR_TYPE_RINGBUF: return BPF_DYNPTR_TYPE_RINGBUF; + case DYNPTR_TYPE_SKB: + return BPF_DYNPTR_TYPE_SKB; default: return BPF_DYNPTR_TYPE_INVALID; } @@ -6295,6 +6297,9 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx, case DYNPTR_TYPE_RINGBUF: err_extra = "ringbuf"; break; + case DYNPTR_TYPE_SKB: + err_extra = "skb "; + break; default: err_extra = ""; break; @@ -6737,6 +6742,24 @@ static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state return state->stack[spi].spilled_ptr.ref_obj_id; } +static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env, + struct bpf_reg_state *reg) +{ + struct bpf_func_state *state = func(env, reg); + int spi; + + if (reg->type == CONST_PTR_TO_DYNPTR) + return reg->dynptr.type; + + spi = __get_spi(reg->off); + if (spi < 0) { + verbose(env, "verifier internal error: invalid spi when querying dynptr type\n"); + return BPF_DYNPTR_TYPE_INVALID; + } + + return state->stack[spi].spilled_ptr.dynptr.type; +} + static int check_func_arg(struct bpf_verifier_env *env, u32 arg, struct bpf_call_arg_meta *meta, const struct bpf_func_proto *fn, @@ -8383,6 +8406,27 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn break; } + case BPF_FUNC_dynptr_write: + { + enum bpf_dynptr_type dynptr_type; + struct bpf_reg_state *reg; + + reg = get_dynptr_arg_reg(env, fn, regs); + if (!reg) + return -EFAULT; + + dynptr_type = dynptr_get_type(env, reg); + if (dynptr_type == BPF_DYNPTR_TYPE_INVALID) + return -EFAULT; + + if (dynptr_type == BPF_DYNPTR_TYPE_SKB) + /* this will trigger clear_all_pkt_pointers(), which will + * invalidate all dynptr slices associated with the skb + */ + changes_data = true; + + break; + } case BPF_FUNC_user_ringbuf_drain: err = __check_func_call(env, insn, insn_idx_p, meta.subprogno, set_user_ringbuf_callback_state); @@ -8898,6 +8942,7 @@ enum special_kfunc_type { KF_bpf_rbtree_remove, KF_bpf_rbtree_add, KF_bpf_rbtree_first, + KF_bpf_dynptr_from_skb, }; BTF_SET_START(special_kfunc_set) @@ -8912,6 +8957,7 @@ BTF_ID(func, bpf_rdonly_cast) BTF_ID(func, bpf_rbtree_remove) BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) +BTF_ID(func, bpf_dynptr_from_skb) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8928,6 +8974,7 @@ BTF_ID(func, bpf_rcu_read_unlock) BTF_ID(func, bpf_rbtree_remove) BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) +BTF_ID(func, bpf_dynptr_from_skb) static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta) { @@ -9682,6 +9729,9 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (is_kfunc_arg_uninit(btf, &args[i])) dynptr_arg_type |= MEM_UNINIT; + if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) + dynptr_arg_type |= DYNPTR_TYPE_SKB; + ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type); if (ret < 0) return ret; @@ -16356,6 +16406,17 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); *cnt = 1; + } else if (desc->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) { + bool seen_direct_write = env->seen_direct_write; + bool is_rdonly = !may_access_direct_pkt_data(env, NULL, BPF_WRITE); + + if (is_rdonly) + insn->imm = BPF_CALL_IMM(bpf_dynptr_from_skb_rdonly); + + /* restore env->seen_direct_write to its original value, since + * may_access_direct_pkt_data mutates it + */ + env->seen_direct_write = seen_direct_write; } return 0; } diff --git a/net/core/filter.c b/net/core/filter.c index 1d6f165923bf..f3afa31a9b10 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1721,6 +1721,12 @@ static const struct bpf_func_proto bpf_skb_store_bytes_proto = { .arg5_type = ARG_ANYTHING, }; +int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, + u32 len, u64 flags) +{ + return ____bpf_skb_store_bytes(skb, offset, from, len, flags); +} + BPF_CALL_4(bpf_skb_load_bytes, const struct sk_buff *, skb, u32, offset, void *, to, u32, len) { @@ -1751,6 +1757,11 @@ static const struct bpf_func_proto bpf_skb_load_bytes_proto = { .arg4_type = ARG_CONST_SIZE, }; +int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len) +{ + return ____bpf_skb_load_bytes(skb, offset, to, len); +} + BPF_CALL_4(bpf_flow_dissector_load_bytes, const struct bpf_flow_dissector *, ctx, u32, offset, void *, to, u32, len) @@ -11621,3 +11632,59 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id) return func; } + +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in vmlinux BTF"); +__bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, + struct bpf_dynptr_kern *ptr__uninit) +{ + if (flags) { + bpf_dynptr_set_null(ptr__uninit); + return -EINVAL; + } + + bpf_dynptr_init(ptr__uninit, skb, BPF_DYNPTR_TYPE_SKB, 0, skb->len); + + return 0; +} +__diag_pop(); + +int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, + struct bpf_dynptr_kern *ptr__uninit) +{ + int err; + + err = bpf_dynptr_from_skb(skb, flags, ptr__uninit); + if (err) + return err; + + bpf_dynptr_set_rdonly(ptr__uninit); + + return 0; +} + +BTF_SET8_START(bpf_kfunc_check_set_skb) +BTF_ID_FLAGS(func, bpf_dynptr_from_skb) +BTF_SET8_END(bpf_kfunc_check_set_skb) + +static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { + .owner = THIS_MODULE, + .set = &bpf_kfunc_check_set_skb, +}; + +static int __init bpf_kfunc_init(void) +{ + int ret; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_ACT, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SK_SKB, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SOCKET_FILTER, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SKB, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_OUT, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_IN, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_XMIT, &bpf_kfunc_set_skb); + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); +} +late_initcall(bpf_kfunc_init); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 62ce1f5d1b1d..d0351d30e551 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5325,11 +5325,17 @@ union bpf_attr { * Description * Write *len* bytes from *src* into *dst*, starting from *offset* * into *dst*. - * *flags* is currently unused. + * + * *flags* must be 0 except for skb-type dynptrs. + * + * For skb-type dynptrs: + * * For *flags*, please see the flags accepted by + * **bpf_skb_store_bytes**\ (). * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length * of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst* - * is a read-only dynptr or if *flags* is not 0. + * is a read-only dynptr or if *flags* is not correct. For skb-type dynptrs, + * other errors correspond to errors returned by **bpf_skb_store_bytes**\ (). * * void *bpf_dynptr_data(const struct bpf_dynptr *ptr, u32 offset, u32 len) * Description @@ -5337,6 +5343,9 @@ union bpf_attr { * * *len* must be a statically known value. The returned data slice * is invalidated whenever the dynptr is invalidated. + * + * skb type dynptrs may not use bpf_dynptr_data. They should + * instead use bpf_dynptr_slice and bpf_dynptr_slice_rdwr. * Return * Pointer to the underlying dynptr data, NULL if the dynptr is * read-only, if the dynptr is invalid, or if the offset and length From patchwork Sun Feb 26 08:51:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152339 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DF77C6FA8E for ; Sun, 26 Feb 2023 08:52:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229630AbjBZIw3 (ORCPT ); Sun, 26 Feb 2023 03:52:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229592AbjBZIw1 (ORCPT ); Sun, 26 Feb 2023 03:52:27 -0500 Received: from mail-pg1-x52a.google.com (mail-pg1-x52a.google.com [IPv6:2607:f8b0:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 047D914983; Sun, 26 Feb 2023 00:52:11 -0800 (PST) Received: by mail-pg1-x52a.google.com with SMTP id 130so1900535pgg.3; Sun, 26 Feb 2023 00:52:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=wYW+fhCESE1QdQQwoGcuoq1U+vuG16c7gZSvSBYjdeA=; b=Rxp8cRVmFsPhrtio20my1FIMhve1R88hfmuUhrIBxHM1NThxb5iVd8GXPaUP18q3IR zBPiME9mkJkOgsgz0VZpMPC21kCe1pW1v8Spf/ve3gkwffz/sSAhbFRe+EcMPtmfOZyN K/eWYNkPeT1Ch93BewKyGD4eCTb2yT+xpv6rxy8SmKltyxr9YuQ0tby+o2BpW6X/vZdp ARnkxgIYu1+bv2HPdRLsPFY4DpyInrzT64TXUfKzqOC5+t4YX4JGT6FaGERGbe4DV5Zx PHaCxOe0oURjd2uAw7iT1cJpzVG8AVLFamGtpqgJ2pTW7WMXA9sIyAV/m1SK7OKO4EX0 oICw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=wYW+fhCESE1QdQQwoGcuoq1U+vuG16c7gZSvSBYjdeA=; b=amBvl6/boiQ0X1XNZzN579WAsbhGnbNNHVIVI9jCig5fkMsoi48Ea0kcUlrNfTKo13 ZVeOCQ5soAuq/W5m3s/jJvNgk2/g3SaDOxxF2ASdGy8rJZvcVbKRZzfY1cEjMCHSogfT KAyJHQwNcBMY8LVt1FOTd5o3zG0anzOE7ypKfYN7zqLACOzA3vu78dZImG++PSYKVEco nTv/3lKHpS8QF4QN7kCitH8nVKO2d0DlLWhH+4EcbhJCwTTadqX56R66g91FbHq7e09H 6AKllWZJ5qT/2el0nkGWiQ+S6OxVRffXcpLyx99wW1gsp4Hdx2C8+IBQkvtrCqjrbqNp I9xw== X-Gm-Message-State: AO0yUKV7lBOeLQSnWjSWB3DRQUhsnXCWm9w8hsDuTro8GUG1VAVnpoVd KbMIIC43ByfnZvu/MOEWvQhWWaoeYvY= X-Google-Smtp-Source: AK7set980aR2wGyGSSFuT3AvUv7DSJZ52+5xiXWMPf7Cqh8nx2q0HNXYz9i8vzgjE0MeLfbcXTRxRg== X-Received: by 2002:a62:1e03:0:b0:5df:5310:e2ee with SMTP id e3-20020a621e03000000b005df5310e2eemr6785582pfe.29.1677401531266; Sun, 26 Feb 2023 00:52:11 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:10 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 08/10] bpf: Add xdp dynptrs Date: Sun, 26 Feb 2023 00:51:18 -0800 Message-Id: <20230226085120.3907863-9-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add xdp dynptrs, which are dynptrs whose underlying pointer points to a xdp_buff. The dynptr acts on xdp data. xdp dynptrs have two main benefits. One is that they allow operations on sizes that are not statically known at compile-time (eg variable-sized accesses). Another is that parsing the packet data through dynptrs (instead of through direct access of xdp->data and xdp->data_end) can be more ergonomic and less brittle (eg does not need manual if checking for being within bounds of data_end). For reads and writes on the dynptr, this includes reading/writing from/to and across fragments. Data slices through the bpf_dynptr_data API are not supported; instead bpf_dynptr_slice() and bpf_dynptr_slice_rdwr() should be used. For examples of how xdp dynptrs can be used, please see the attached selftests. Signed-off-by: Joanne Koong --- include/linux/bpf.h | 8 +++++++- include/linux/filter.h | 14 +++++++++++++ include/uapi/linux/bpf.h | 2 +- kernel/bpf/helpers.c | 9 ++++++++- kernel/bpf/verifier.c | 10 +++++++++ net/core/filter.c | 37 ++++++++++++++++++++++++++++++++-- tools/include/uapi/linux/bpf.h | 2 +- 7 files changed, 76 insertions(+), 6 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index e7436d7615b0..23ec684e660d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -610,11 +610,15 @@ enum bpf_type_flag { /* DYNPTR points to sk_buff */ DYNPTR_TYPE_SKB = BIT(15 + BPF_BASE_TYPE_BITS), + /* DYNPTR points to xdp_buff */ + DYNPTR_TYPE_XDP = BIT(16 + BPF_BASE_TYPE_BITS), + __BPF_TYPE_FLAG_MAX, __BPF_TYPE_LAST_FLAG = __BPF_TYPE_FLAG_MAX - 1, }; -#define DYNPTR_TYPE_FLAG_MASK (DYNPTR_TYPE_LOCAL | DYNPTR_TYPE_RINGBUF | DYNPTR_TYPE_SKB) +#define DYNPTR_TYPE_FLAG_MASK (DYNPTR_TYPE_LOCAL | DYNPTR_TYPE_RINGBUF | DYNPTR_TYPE_SKB \ + | DYNPTR_TYPE_XDP) /* Max number of base types. */ #define BPF_BASE_TYPE_LIMIT (1UL << BPF_BASE_TYPE_BITS) @@ -1151,6 +1155,8 @@ enum bpf_dynptr_type { BPF_DYNPTR_TYPE_RINGBUF, /* Underlying data is a sk_buff */ BPF_DYNPTR_TYPE_SKB, + /* Underlying data is a xdp_buff */ + BPF_DYNPTR_TYPE_XDP, }; int bpf_dynptr_check_size(u32 size); diff --git a/include/linux/filter.h b/include/linux/filter.h index de18e844d15e..3f6992261ec5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1546,6 +1546,8 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u64 index int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len); int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags); +int __bpf_xdp_load_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len); +int __bpf_xdp_store_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len); #else /* CONFIG_NET */ static inline int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len) @@ -1558,6 +1560,18 @@ static inline int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, { return -EOPNOTSUPP; } + +static inline int __bpf_xdp_load_bytes(struct xdp_buff *xdp, u32 offset, + void *buf, u32 len) +{ + return -EOPNOTSUPP; +} + +static inline int __bpf_xdp_store_bytes(struct xdp_buff *xdp, u32 offset, + void *buf, u32 len) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_NET */ #endif /* __LINUX_FILTER_H__ */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index d0351d30e551..faa304c926cf 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5344,7 +5344,7 @@ union bpf_attr { * *len* must be a statically known value. The returned data slice * is invalidated whenever the dynptr is invalidated. * - * skb type dynptrs may not use bpf_dynptr_data. They should + * skb and xdp type dynptrs may not use bpf_dynptr_data. They should * instead use bpf_dynptr_slice and bpf_dynptr_slice_rdwr. * Return * Pointer to the underlying dynptr data, NULL if the dynptr is diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 1863bea0a21f..78fad0e84ca4 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1530,6 +1530,8 @@ BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern return 0; case BPF_DYNPTR_TYPE_SKB: return __bpf_skb_load_bytes(src->data, src->offset + offset, dst, len); + case BPF_DYNPTR_TYPE_XDP: + return __bpf_xdp_load_bytes(src->data, src->offset + offset, dst, len); default: WARN_ONCE(true, "bpf_dynptr_read: unknown dynptr type %d\n", type); return -EFAULT; @@ -1576,6 +1578,10 @@ BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, v case BPF_DYNPTR_TYPE_SKB: return __bpf_skb_store_bytes(dst->data, dst->offset + offset, src, len, flags); + case BPF_DYNPTR_TYPE_XDP: + if (flags) + return -EINVAL; + return __bpf_xdp_store_bytes(dst->data, dst->offset + offset, src, len); default: WARN_ONCE(true, "bpf_dynptr_write: unknown dynptr type %d\n", type); return -EFAULT; @@ -1615,7 +1621,8 @@ BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u3 case BPF_DYNPTR_TYPE_RINGBUF: return (unsigned long)(ptr->data + ptr->offset + offset); case BPF_DYNPTR_TYPE_SKB: - /* skb dynptrs should use bpf_dynptr_slice / bpf_dynptr_slice_rdwr */ + case BPF_DYNPTR_TYPE_XDP: + /* skb and xdp dynptrs should use bpf_dynptr_slice / bpf_dynptr_slice_rdwr */ return 0; default: WARN_ONCE(true, "bpf_dynptr_data: unknown dynptr type %d\n", type); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ef38ec52569a..cbb8c0178372 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -752,6 +752,8 @@ static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type) return BPF_DYNPTR_TYPE_RINGBUF; case DYNPTR_TYPE_SKB: return BPF_DYNPTR_TYPE_SKB; + case DYNPTR_TYPE_XDP: + return BPF_DYNPTR_TYPE_XDP; default: return BPF_DYNPTR_TYPE_INVALID; } @@ -6300,6 +6302,9 @@ int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx, case DYNPTR_TYPE_SKB: err_extra = "skb "; break; + case DYNPTR_TYPE_XDP: + err_extra = "xdp "; + break; default: err_extra = ""; break; @@ -8943,6 +8948,7 @@ enum special_kfunc_type { KF_bpf_rbtree_add, KF_bpf_rbtree_first, KF_bpf_dynptr_from_skb, + KF_bpf_dynptr_from_xdp, }; BTF_SET_START(special_kfunc_set) @@ -8958,6 +8964,7 @@ BTF_ID(func, bpf_rbtree_remove) BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) BTF_ID(func, bpf_dynptr_from_skb) +BTF_ID(func, bpf_dynptr_from_xdp) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8975,6 +8982,7 @@ BTF_ID(func, bpf_rbtree_remove) BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) BTF_ID(func, bpf_dynptr_from_skb) +BTF_ID(func, bpf_dynptr_from_xdp) static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta) { @@ -9731,6 +9739,8 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) dynptr_arg_type |= DYNPTR_TYPE_SKB; + else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_xdp]) + dynptr_arg_type |= DYNPTR_TYPE_XDP; ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type); if (ret < 0) diff --git a/net/core/filter.c b/net/core/filter.c index f3afa31a9b10..c692046fa7f6 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3839,7 +3839,7 @@ static const struct bpf_func_proto sk_skb_change_head_proto = { .arg3_type = ARG_ANYTHING, }; -BPF_CALL_1(bpf_xdp_get_buff_len, struct xdp_buff*, xdp) +BPF_CALL_1(bpf_xdp_get_buff_len, struct xdp_buff*, xdp) { return xdp_get_buff_len(xdp); } @@ -3999,6 +3999,11 @@ static const struct bpf_func_proto bpf_xdp_load_bytes_proto = { .arg4_type = ARG_CONST_SIZE, }; +int __bpf_xdp_load_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len) +{ + return ____bpf_xdp_load_bytes(xdp, offset, buf, len); +} + BPF_CALL_4(bpf_xdp_store_bytes, struct xdp_buff *, xdp, u32, offset, void *, buf, u32, len) { @@ -4026,6 +4031,11 @@ static const struct bpf_func_proto bpf_xdp_store_bytes_proto = { .arg4_type = ARG_CONST_SIZE, }; +int __bpf_xdp_store_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len) +{ + return ____bpf_xdp_store_bytes(xdp, offset, buf, len); +} + static int bpf_xdp_frags_increase_tail(struct xdp_buff *xdp, int offset) { struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); @@ -11648,6 +11658,19 @@ __bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, return 0; } + +__bpf_kfunc int bpf_dynptr_from_xdp(struct xdp_buff *xdp, u64 flags, + struct bpf_dynptr_kern *ptr__uninit) +{ + if (flags) { + bpf_dynptr_set_null(ptr__uninit); + return -EINVAL; + } + + bpf_dynptr_init(ptr__uninit, xdp, BPF_DYNPTR_TYPE_XDP, 0, xdp_get_buff_len(xdp)); + + return 0; +} __diag_pop(); int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, @@ -11668,11 +11691,20 @@ BTF_SET8_START(bpf_kfunc_check_set_skb) BTF_ID_FLAGS(func, bpf_dynptr_from_skb) BTF_SET8_END(bpf_kfunc_check_set_skb) +BTF_SET8_START(bpf_kfunc_check_set_xdp) +BTF_ID_FLAGS(func, bpf_dynptr_from_xdp) +BTF_SET8_END(bpf_kfunc_check_set_xdp) + static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { .owner = THIS_MODULE, .set = &bpf_kfunc_check_set_skb, }; +static const struct btf_kfunc_id_set bpf_kfunc_set_xdp = { + .owner = THIS_MODULE, + .set = &bpf_kfunc_check_set_xdp, +}; + static int __init bpf_kfunc_init(void) { int ret; @@ -11685,6 +11717,7 @@ static int __init bpf_kfunc_init(void) ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_OUT, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_IN, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_XMIT, &bpf_kfunc_set_skb); - return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); } late_initcall(bpf_kfunc_init); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index d0351d30e551..faa304c926cf 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5344,7 +5344,7 @@ union bpf_attr { * *len* must be a statically known value. The returned data slice * is invalidated whenever the dynptr is invalidated. * - * skb type dynptrs may not use bpf_dynptr_data. They should + * skb and xdp type dynptrs may not use bpf_dynptr_data. They should * instead use bpf_dynptr_slice and bpf_dynptr_slice_rdwr. * Return * Pointer to the underlying dynptr data, NULL if the dynptr is From patchwork Sun Feb 26 08:51:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152338 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E50C0C7EE31 for ; Sun, 26 Feb 2023 08:52:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229578AbjBZIwa (ORCPT ); Sun, 26 Feb 2023 03:52:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbjBZIw1 (ORCPT ); Sun, 26 Feb 2023 03:52:27 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7925414E98; Sun, 26 Feb 2023 00:52:13 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id x34so3232996pjj.0; Sun, 26 Feb 2023 00:52:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=6XmAB57B8w1uOg5nRsBG+h5HpUo+xYwgJylCU6buYSU=; b=QS6WILk7cFWPflxMQmJQBSXK2jh/BS+HOBd3kEpWRi2jJyTH4UosFsKyfpoQbZoo+T E1nbs0ebx0m3ERvSQyt1tcSi9NJob9TXVKDqnyoTMhxUxB7x4YEGNELcxZ+KEfnzWJeK PtA3IhbdxvFScdKfNqMa2/QQOkdJW2JIl0TXE14FvhjpboBaO1ihMfPmhqyPvOyu9sHq sHqbKHcIZiQZhr/GI2zsvpIQhIQBsUoPqVuA5XvJEJQI+GU2zejMVCkSTrS7iEdQxK/4 EGwiEFTvfe0kGU+gQ+VxrS4RfyAabjzwK/+Ky/x5nUzezAlKMUaeXHEml8a84M2B69TV L5Ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=6XmAB57B8w1uOg5nRsBG+h5HpUo+xYwgJylCU6buYSU=; b=AxuIKZLZUA6Y7052x797jgYuuLJAuxzkyNWBrwF/hyToNJsoDLBp7UQw0QlDt8aAkk 6xtLyuDFUjZeskseSnbTo4XXG6nYdLZQsRwXsLh4H414CpOqyMoNz/+yj9dwIpf8hZuj OxC6K/ApJNa2YQ9V/NLhqFlwiE6YtA+AA88vPr0mhw+3TEbHHCcs7kd4sOPiiffNFf+J 1JEhpdJOns+MR2cpWOHCdwM+YPaaLbn+LdBmRSlqankdSYiiNIG/MAd2zAmEQRt/TFbg AFNlCFEoplmL/eVaz06eBCDMV6/ZzNJm9OUDuVgN6QFR5YnSEDt59HAEKTuOGaZ5LZ++ wfmA== X-Gm-Message-State: AO0yUKXOkf4HI85yMJRl4XuLLLlgqQTha5pM4iVJH0sUwUK4wu1CwLZv z8iCWtuQij5z5Va4bDhF6qha9xPMu4c= X-Google-Smtp-Source: AK7set9ls8lXG1/NZY3U3AhCbL7YYJXn2HuQm/b8wioCv7tnCGMud3nfAIDyQtmt3uJS2aZYGBrN9w== X-Received: by 2002:a05:6a20:4b0f:b0:bf:e6c:758b with SMTP id fp15-20020a056a204b0f00b000bf0e6c758bmr12525770pzb.4.1677401532638; Sun, 26 Feb 2023 00:52:12 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:12 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 09/10] bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwr Date: Sun, 26 Feb 2023 00:51:19 -0800 Message-Id: <20230226085120.3907863-10-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Two new kfuncs are added, bpf_dynptr_slice and bpf_dynptr_slice_rdwr. The user must pass in a buffer to store the contents of the data slice if a direct pointer to the data cannot be obtained. For skb and xdp type dynptrs, these two APIs are the only way to obtain a data slice. However, for other types of dynptrs, there is no difference between bpf_dynptr_slice(_rdwr) and bpf_dynptr_data. For skb type dynptrs, the data is copied into the user provided buffer if any of the data is not in the linear portion of the skb. For xdp type dynptrs, the data is copied into the user provided buffer if the data is between xdp frags. If the skb is cloned and a call to bpf_dynptr_data_rdwr is made, then the skb will be uncloned (see bpf_unclone_prologue()). Please note that any bpf_dynptr_write() automatically invalidates any prior data slices of the skb dynptr. This is because the skb may be cloned or may need to pull its paged buffer into the head. As such, any bpf_dynptr_write() will automatically have its prior data slices invalidated, even if the write is to data in the skb head of an uncloned skb. Please note as well that any other helper calls that change the underlying packet buffer (eg bpf_skb_pull_data()) invalidates any data slices of the skb dynptr as well, for the same reasons. Signed-off-by: Joanne Koong --- include/linux/filter.h | 14 ++++ include/uapi/linux/bpf.h | 5 ++ kernel/bpf/helpers.c | 138 +++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 125 ++++++++++++++++++++++++++++- net/core/filter.c | 6 +- tools/include/uapi/linux/bpf.h | 5 ++ 6 files changed, 286 insertions(+), 7 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 3f6992261ec5..efa5d4a1677e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1548,6 +1548,9 @@ int __bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags); int __bpf_xdp_load_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len); int __bpf_xdp_store_bytes(struct xdp_buff *xdp, u32 offset, void *buf, u32 len); +void *bpf_xdp_pointer(struct xdp_buff *xdp, u32 offset, u32 len); +void bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, + void *buf, unsigned long len, bool flush); #else /* CONFIG_NET */ static inline int __bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len) @@ -1572,6 +1575,17 @@ static inline int __bpf_xdp_store_bytes(struct xdp_buff *xdp, u32 offset, { return -EOPNOTSUPP; } + +static inline void *bpf_xdp_pointer(struct xdp_buff *xdp, u32 offset, u32 len) +{ + return NULL; +} + +static inline void *bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, void *buf, + unsigned long len, bool flush) +{ + return NULL; +} #endif /* CONFIG_NET */ #endif /* __LINUX_FILTER_H__ */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index faa304c926cf..c9699304aed2 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5329,6 +5329,11 @@ union bpf_attr { * *flags* must be 0 except for skb-type dynptrs. * * For skb-type dynptrs: + * * All data slices of the dynptr are automatically + * invalidated after **bpf_dynptr_write**\ (). This is + * because writing may pull the skb and change the + * underlying packet buffer. + * * * For *flags*, please see the flags accepted by * **bpf_skb_store_bytes**\ (). * Return diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 78fad0e84ca4..33055e4c9e2e 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2194,6 +2194,142 @@ __bpf_kfunc struct task_struct *bpf_task_from_pid(s32 pid) return p; } +/** + * bpf_dynptr_slice - Obtain a read-only pointer to the dynptr data. + * + * For non-skb and non-xdp type dynptrs, there is no difference between + * bpf_dynptr_slice and bpf_dynptr_data. + * + * If the intention is to write to the data slice, please use + * bpf_dynptr_slice_rdwr. + * + * The user must check that the returned pointer is not null before using it. + * + * Please note that in the case of skb and xdp dynptrs, bpf_dynptr_slice + * does not change the underlying packet data pointers, so a call to + * bpf_dynptr_slice will not invalidate any ctx->data/data_end pointers in + * the bpf program. + * + * @ptr: The dynptr whose data slice to retrieve + * @offset: Offset into the dynptr + * @buffer: User-provided buffer to copy contents into + * @buffer__szk: Size (in bytes) of the buffer. This is the length of the + * requested slice. This must be a constant. + * + * @returns: NULL if the call failed (eg invalid dynptr), pointer to a read-only + * data slice (can be either direct pointer to the data or a pointer to the user + * provided buffer, with its contents containing the data, if unable to obtain + * direct pointer) + */ +__bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset, + void *buffer, u32 buffer__szk) +{ + enum bpf_dynptr_type type; + u32 len = buffer__szk; + int err; + + if (!ptr->data) + return 0; + + err = bpf_dynptr_check_off_len(ptr, offset, len); + if (err) + return 0; + + type = bpf_dynptr_get_type(ptr); + + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + case BPF_DYNPTR_TYPE_RINGBUF: + return ptr->data + ptr->offset + offset; + case BPF_DYNPTR_TYPE_SKB: + return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer); + case BPF_DYNPTR_TYPE_XDP: + { + void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset + offset, len); + if (xdp_ptr) + return xdp_ptr; + + bpf_xdp_copy_buf(ptr->data, ptr->offset + offset, buffer, len, false); + return buffer; + } + default: + WARN_ONCE(true, "unknown dynptr type %d\n", type); + return 0; + } +} + +/** + * bpf_dynptr_slice_rdwr - Obtain a writable pointer to the dynptr data. + * + * For non-skb and non-xdp type dynptrs, there is no difference between + * bpf_dynptr_slice and bpf_dynptr_data. + * + * The returned pointer is writable and may point to either directly the dynptr + * data at the requested offset or to the buffer if unable to obtain a direct + * data pointer to (example: the requested slice is to the paged area of an skb + * packet). In the case where the returned pointer is to the buffer, the user + * is responsible for persisting writes through calling bpf_dynptr_write(). This + * usually looks something like this pattern: + * + * struct eth_hdr *eth = bpf_dynptr_slice_rdwr(&dynptr, 0, buffer, sizeof(buffer)); + * if (!eth) + * return TC_ACT_SHOT; + * + * // mutate eth header // + * + * if (eth == buffer) + * bpf_dynptr_write(&ptr, 0, buffer, sizeof(buffer), 0); + * + * Please note that, as in the example above, the user must check that the + * returned pointer is not null before using it. + * + * Please also note that in the case of skb and xdp dynptrs, bpf_dynptr_slice_rdwr + * does not change the underlying packet data pointers, so a call to + * bpf_dynptr_slice_rdwr will not invalidate any ctx->data/data_end pointers in + * the bpf program. + * + * @ptr: The dynptr whose data slice to retrieve + * @offset: Offset into the dynptr + * @buffer: User-provided buffer to copy contents into + * @buffer__szk: Size (in bytes) of the buffer. This is the length of the + * requested slice. This must be a constant. + * + * @returns: NULL if the call failed (eg invalid dynptr), pointer to a + * data slice (can be either direct pointer to the data or a pointer to the user + * provided buffer, with its contents containing the data, if unable to obtain + * direct pointer) + */ +__bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 offset, + void *buffer, u32 buffer__szk) +{ + if (!ptr->data || bpf_dynptr_is_rdonly(ptr)) + return 0; + + /* bpf_dynptr_slice_rdwr is the same logic as bpf_dynptr_slice. + * + * For skb-type dynptrs, it is safe to write into the returned pointer + * if the bpf program allows skb data writes. There are two possiblities + * that may occur when calling bpf_dynptr_slice_rdwr: + * + * 1) The requested slice is in the head of the skb. In this case, the + * returned pointer is directly to skb data, and if the skb is cloned, the + * verifier will have uncloned it (see bpf_unclone_prologue()) already. + * The pointer can be directly written into. + * + * 2) Some portion of the requested slice is in the paged buffer area. + * In this case, the requested data will be copied out into the buffer + * and the returned pointer will be a pointer to the buffer. The skb + * will not be pulled. To persist the write, the user will need to call + * bpf_dynptr_write(), which will pull the skb and commit the write. + * + * Similarly for xdp programs, if the requested slice is not across xdp + * fragments, then a direct pointer will be returned, otherwise the data + * will be copied out into the buffer and the user will need to call + * bpf_dynptr_write() to commit changes. + */ + return bpf_dynptr_slice(ptr, offset, buffer, buffer__szk); +} + __bpf_kfunc void *bpf_cast_to_kern_ctx(void *obj) { return obj; @@ -2263,6 +2399,8 @@ BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) BTF_ID_FLAGS(func, bpf_rdonly_cast) BTF_ID_FLAGS(func, bpf_rcu_read_lock) BTF_ID_FLAGS(func, bpf_rcu_read_unlock) +BTF_ID_FLAGS(func, bpf_dynptr_slice, KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_dynptr_slice_rdwr, KF_RET_NULL) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cbb8c0178372..a9e806545c0f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -759,6 +759,22 @@ static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type) } } +static enum bpf_type_flag get_dynptr_type_flag(enum bpf_dynptr_type type) +{ + switch (type) { + case BPF_DYNPTR_TYPE_LOCAL: + return DYNPTR_TYPE_LOCAL; + case BPF_DYNPTR_TYPE_RINGBUF: + return DYNPTR_TYPE_RINGBUF; + case BPF_DYNPTR_TYPE_SKB: + return DYNPTR_TYPE_SKB; + case BPF_DYNPTR_TYPE_XDP: + return DYNPTR_TYPE_XDP; + default: + return 0; + } +} + static bool dynptr_type_refcounted(enum bpf_dynptr_type type) { return type == BPF_DYNPTR_TYPE_RINGBUF; @@ -1681,6 +1697,12 @@ static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg) reg->type == PTR_TO_PACKET_END; } +static bool reg_is_dynptr_slice_pkt(const struct bpf_reg_state *reg) +{ + return base_type(reg->type) == PTR_TO_MEM && + (reg->type & DYNPTR_TYPE_SKB || reg->type & DYNPTR_TYPE_XDP); +} + /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */ static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg, enum bpf_reg_type which) @@ -7429,6 +7451,9 @@ static int check_func_proto(const struct bpf_func_proto *fn, int func_id) /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END] * are now invalid, so turn them into unknown SCALAR_VALUE. + * + * This also applies to dynptr slices belonging to skb and xdp dynptrs, + * since these slices point to packet data. */ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) { @@ -7436,7 +7461,7 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) struct bpf_reg_state *reg; bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({ - if (reg_is_pkt_pointer_any(reg)) + if (reg_is_pkt_pointer_any(reg) || reg_is_dynptr_slice_pkt(reg)) mark_reg_invalid(env, reg); })); } @@ -8688,6 +8713,11 @@ struct bpf_kfunc_call_arg_meta { struct { struct btf_field *field; } arg_rbtree_root; + struct { + enum bpf_dynptr_type type; + u32 id; + } initialized_dynptr; + u64 mem_size; }; static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) @@ -8761,6 +8791,19 @@ static bool is_kfunc_arg_mem_size(const struct btf *btf, return __kfunc_param_match_suffix(btf, arg, "__sz"); } +static bool is_kfunc_arg_const_mem_size(const struct btf *btf, + const struct btf_param *arg, + const struct bpf_reg_state *reg) +{ + const struct btf_type *t; + + t = btf_type_skip_modifiers(btf, arg->type, NULL); + if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE) + return false; + + return __kfunc_param_match_suffix(btf, arg, "__szk"); +} + static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg) { return __kfunc_param_match_suffix(btf, arg, "__k"); @@ -8949,6 +8992,8 @@ enum special_kfunc_type { KF_bpf_rbtree_first, KF_bpf_dynptr_from_skb, KF_bpf_dynptr_from_xdp, + KF_bpf_dynptr_slice, + KF_bpf_dynptr_slice_rdwr, }; BTF_SET_START(special_kfunc_set) @@ -8965,6 +9010,8 @@ BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) BTF_ID(func, bpf_dynptr_from_skb) BTF_ID(func, bpf_dynptr_from_xdp) +BTF_ID(func, bpf_dynptr_slice) +BTF_ID(func, bpf_dynptr_slice_rdwr) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8983,6 +9030,8 @@ BTF_ID(func, bpf_rbtree_add) BTF_ID(func, bpf_rbtree_first) BTF_ID(func, bpf_dynptr_from_skb) BTF_ID(func, bpf_dynptr_from_xdp) +BTF_ID(func, bpf_dynptr_slice) +BTF_ID(func, bpf_dynptr_slice_rdwr) static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta) { @@ -9062,7 +9111,10 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, if (is_kfunc_arg_callback(env, meta->btf, &args[argno])) return KF_ARG_PTR_TO_CALLBACK; - if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1])) + + if (argno + 1 < nargs && + (is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1]) || + is_kfunc_arg_const_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1]))) arg_mem_size = true; /* This is the catch all argument type of register types supported by @@ -9745,6 +9797,18 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type); if (ret < 0) return ret; + + if (!(dynptr_arg_type & MEM_UNINIT)) { + int id = dynptr_id(env, reg); + + if (id < 0) { + verbose(env, "verifier internal error: failed to obtain dynptr id\n"); + return id; + } + meta->initialized_dynptr.id = id; + meta->initialized_dynptr.type = dynptr_get_type(env, reg); + } + break; } case KF_ARG_PTR_TO_LIST_HEAD: @@ -9840,12 +9904,29 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return ret; break; case KF_ARG_PTR_TO_MEM_SIZE: - ret = check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1); + struct bpf_reg_state *size_reg = ®s[regno + 1]; + const struct btf_param *size_arg = &args[i + 1]; + + ret = check_kfunc_mem_size_reg(env, size_reg, regno + 1); if (ret < 0) { verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1); return ret; } - /* Skip next '__sz' argument */ + + if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) { + if (meta->arg_constant.found) { + verbose(env, "verifier internal error: only one constant argument permitted\n"); + return -EFAULT; + } + if (!tnum_is_const(size_reg->var_off)) { + verbose(env, "R%d must be a known constant\n", regno + 1); + return -EINVAL; + } + meta->arg_constant.found = true; + meta->arg_constant.value = size_reg->var_off.value; + } + + /* Skip next '__sz' or '__szk' argument */ i++; break; case KF_ARG_PTR_TO_CALLBACK: @@ -10082,6 +10163,42 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; regs[BPF_REG_0].btf = desc_btf; regs[BPF_REG_0].btf_id = meta.arg_constant.value; + } else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] || + meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { + enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type); + + mark_reg_known_zero(env, regs, BPF_REG_0); + + if (!meta.arg_constant.found) { + verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n"); + return -EFAULT; + } + + regs[BPF_REG_0].mem_size = meta.arg_constant.value; + + /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */ + regs[BPF_REG_0].type = PTR_TO_MEM | type_flag; + + if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) { + regs[BPF_REG_0].type |= MEM_RDONLY; + } else { + /* this will set env->seen_direct_write to true */ + if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) { + verbose(env, "the prog does not allow writes to packet data\n"); + return -EINVAL; + } + } + + if (!meta.initialized_dynptr.id) { + verbose(env, "verifier internal error: no dynptr id\n"); + return -EFAULT; + } + regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id; + + /* we don't need to set BPF_REG_0's ref obj id + * because packet slices are not refcounted (see + * dynptr_type_refcounted) + */ } else { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); diff --git a/net/core/filter.c b/net/core/filter.c index c692046fa7f6..8f3124e06133 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3894,8 +3894,8 @@ static const struct bpf_func_proto bpf_xdp_adjust_head_proto = { .arg2_type = ARG_ANYTHING, }; -static void bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, - void *buf, unsigned long len, bool flush) +void bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, + void *buf, unsigned long len, bool flush) { unsigned long ptr_len, ptr_off = 0; skb_frag_t *next_frag, *end_frag; @@ -3941,7 +3941,7 @@ static void bpf_xdp_copy_buf(struct xdp_buff *xdp, unsigned long off, } } -static void *bpf_xdp_pointer(struct xdp_buff *xdp, u32 offset, u32 len) +void *bpf_xdp_pointer(struct xdp_buff *xdp, u32 offset, u32 len) { struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); u32 size = xdp->data_end - xdp->data; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index faa304c926cf..c9699304aed2 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5329,6 +5329,11 @@ union bpf_attr { * *flags* must be 0 except for skb-type dynptrs. * * For skb-type dynptrs: + * * All data slices of the dynptr are automatically + * invalidated after **bpf_dynptr_write**\ (). This is + * because writing may pull the skb and change the + * underlying packet buffer. + * * * For *flags*, please see the flags accepted by * **bpf_skb_store_bytes**\ (). * Return From patchwork Sun Feb 26 08:51:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joanne Koong X-Patchwork-Id: 13152340 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E1DEC6FA8E for ; Sun, 26 Feb 2023 08:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229587AbjBZIwq (ORCPT ); Sun, 26 Feb 2023 03:52:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229636AbjBZIwa (ORCPT ); Sun, 26 Feb 2023 03:52:30 -0500 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E45314982; Sun, 26 Feb 2023 00:52:19 -0800 (PST) Received: by mail-pj1-x102b.google.com with SMTP id m8-20020a17090a4d8800b002377bced051so7172960pjh.0; Sun, 26 Feb 2023 00:52:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Kk4i2Zww/kLL1evWdIC4LHF5xaqOzjJGrEI90rS36LQ=; b=qrBMe94AbfXQ7wxuWels0fvU7vF8TF9M3eV0zccg4dO9f7xqmP2WNBIJCEr5V9VTXC K3NLi+/La4HbxSrkRErJ+8UDLSP8ihxI9De8/Mc2tiuq/ZJn4ydy6A3mC9h3PhymgbAo Gn2oVFg6Fui+mSPt7e1/PenlMjS7AqTcY7DguzQEK2xAnuH7hp90+bbSFcUCAdldvS5+ eXMGtLkSaYJlZePcD3EMbfO5OhzlRyi3sBqAOeYudjDboeTjgna9/ZE6jtJzfhZJ2hg/ j/z2p5zhlV0L1Yyi1pzsCcUVnqVjufG1+Q4M0IUqWgOknba19xqbjFS8SqRSJorh8R76 vL9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Kk4i2Zww/kLL1evWdIC4LHF5xaqOzjJGrEI90rS36LQ=; b=aU7jOtmzLRxaUN8onykR5PKZ+reXAwQkRanIdMlK+Ra1E6wF6WEC2zLWZsKBXEisSW hh5FFAv+o6H0iByq1AsKUB0V1NOXmg9UxpwZuJ8gfC9HqUPFP3dDY2afpuzbey3vQq8C G9JNdqZlF0RWRhChl3xqzB+Yn6ug0LeSrJeQ1RlikPtn1zmg7BAxymZMo8ck556fg5BC U97iNd3ZwFfXXIu+sBQ1wq74lxPuzVBNejGte0+JLp5LOrCzLpAuSnf7dq+/zc8HPzn2 hqaoLFkXyImXGKspn1uHgwMvysqp/d0++a2hI2QnuI4mvtcQtGXI0A77Q4pMqnXH9B3J mmig== X-Gm-Message-State: AO0yUKUg4f7IpX8ZxPJ46+EP2+O76MO43g5UFkBDzc22OmBj2WDl3h2y 27B//zZ63Wo1O7YFJw29pWchqP/wbJg= X-Google-Smtp-Source: AK7set8+1KAm7xwvDuqv0tgUpGiUYgO1SXVVBA/gcJdzrgZjNFnKDHWJZY1ds98g8fj+3kGtbZUBeg== X-Received: by 2002:a05:6a20:698d:b0:cc:1fef:99ba with SMTP id t13-20020a056a20698d00b000cc1fef99bamr11990340pzk.8.1677401537190; Sun, 26 Feb 2023 00:52:17 -0800 (PST) Received: from gatsby.corp.tfbnw.net (75-172-126-232.tukw.qwest.net. [75.172.126.232]) by smtp.gmail.com with ESMTPSA id s10-20020a62e70a000000b00592591d1634sm2227299pfh.97.2023.02.26.00.52.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 00:52:16 -0800 (PST) From: Joanne Koong To: bpf@vger.kernel.org Cc: martin.lau@kernel.org, andrii@kernel.org, ast@kernel.org, memxor@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, toke@kernel.org, Joanne Koong Subject: [PATCH v12 bpf-next 10/10] selftests/bpf: tests for using dynptrs to parse skb and xdp buffers Date: Sun, 26 Feb 2023 00:51:20 -0800 Message-Id: <20230226085120.3907863-11-joannelkoong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230226085120.3907863-1-joannelkoong@gmail.com> References: <20230226085120.3907863-1-joannelkoong@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Test skb and xdp dynptr functionality in the following ways: 1) progs/test_cls_redirect_dynptr.c * Rewrite "progs/test_cls_redirect.c" test to use dynptrs to parse skb data * This is a great example of how dynptrs can be used to simplify a lot of the parsing logic for non-statically known values. When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t cls_redirect"): original version: 0.092 sec with dynptrs: 0.078 sec 2) progs/test_xdp_dynptr.c * Rewrite "progs/test_xdp.c" test to use dynptrs to parse xdp data When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t xdp_attach"): original version: 0.118 sec with dynptrs: 0.094 sec 3) progs/test_l4lb_noinline_dynptr.c * Rewrite "progs/test_l4lb_noinline.c" test to use dynptrs to parse skb data When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t l4lb_all"): original version: 0.062 sec with dynptrs: 0.081 sec For number of processed verifier instructions: original version: 6268 insns with dynptrs: 2588 insns 4) progs/test_parse_tcp_hdr_opt_dynptr.c * Add sample code for parsing tcp hdr opt lookup using dynptrs. This logic is lifted from a real-world use case of packet parsing in katran [0], a layer 4 load balancer. The original version "progs/test_parse_tcp_hdr_opt.c" (not using dynptrs) is included here as well, for comparison. When measuring the user + system time between the original version vs. using dynptrs, and averaging the time for 10 runs (using "time ./test_progs -t parse_tcp_hdr_opt"): original version: 0.031 sec with dynptrs: 0.045 sec 5) progs/dynptr_success.c * Add test case "test_skb_readonly" for testing attempts at writes on a prog type with read-only skb ctx. * Add "test_dynptr_skb_data" for testing that bpf_dynptr_data isn't supported for skb progs. 6) progs/dynptr_fail.c * Add test cases "skb_invalid_data_slice{1,2,3,4}" and "xdp_invalid_data_slice{1,2}" for testing that helpers that modify the underlying packet buffer automatically invalidate the associated data slice. * Add test cases "skb_invalid_ctx" and "xdp_invalid_ctx" for testing that prog types that do not support bpf_dynptr_from_skb/xdp don't have access to the API. * Add test case "dynptr_slice_var_len{1,2}" for testing that variable-sized len can't be passed in to bpf_dynptr_slice * Add test case "skb_invalid_slice_write" for testing that writes to a read-only data slice are rejected by the verifier. * Add test case "data_slice_out_of_bounds_skb" for testing that writes to an area outside the slice are rejected. * Add test case "invalid_slice_rdwr_rdonly" for testing that prog types that don't allow writes to packet data don't accept any calls to bpf_dynptr_slice_rdwr. [0] https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h Signed-off-by: Joanne Koong Acked-by: Andrii Nakryiko --- tools/testing/selftests/bpf/bpf_kfuncs.h | 38 + .../selftests/bpf/prog_tests/cls_redirect.c | 25 + .../testing/selftests/bpf/prog_tests/dynptr.c | 74 +- .../selftests/bpf/prog_tests/l4lb_all.c | 2 + .../bpf/prog_tests/parse_tcp_hdr_opt.c | 93 ++ .../selftests/bpf/prog_tests/xdp_attach.c | 11 +- .../testing/selftests/bpf/progs/dynptr_fail.c | 287 ++++- .../selftests/bpf/progs/dynptr_success.c | 55 +- .../bpf/progs/test_cls_redirect_dynptr.c | 980 ++++++++++++++++++ .../bpf/progs/test_l4lb_noinline_dynptr.c | 487 +++++++++ .../bpf/progs/test_parse_tcp_hdr_opt.c | 119 +++ .../bpf/progs/test_parse_tcp_hdr_opt_dynptr.c | 114 ++ .../selftests/bpf/progs/test_xdp_dynptr.c | 257 +++++ .../selftests/bpf/test_tcp_hdr_options.h | 1 + 14 files changed, 2520 insertions(+), 23 deletions(-) create mode 100644 tools/testing/selftests/bpf/bpf_kfuncs.h create mode 100644 tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c create mode 100644 tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_dynptr.c diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h new file mode 100644 index 000000000000..8c993ec8ceea --- /dev/null +++ b/tools/testing/selftests/bpf/bpf_kfuncs.h @@ -0,0 +1,38 @@ +#ifndef __BPF_KFUNCS__ +#define __BPF_KFUNCS__ + +/* Description + * Initializes an skb-type dynptr + * Returns + * Error code + */ +extern int bpf_dynptr_from_skb(struct __sk_buff *skb, __u64 flags, + struct bpf_dynptr *ptr__uninit) __ksym; + +/* Description + * Initializes an xdp-type dynptr + * Returns + * Error code + */ +extern int bpf_dynptr_from_xdp(struct xdp_md *xdp, __u64 flags, + struct bpf_dynptr *ptr__uninit) __ksym; + +/* Description + * Obtain a read-only pointer to the dynptr's data + * Returns + * Either a direct pointer to the dynptr data or a pointer to the user-provided + * buffer if unable to obtain a direct pointer + */ +extern void *bpf_dynptr_slice(const struct bpf_dynptr *ptr, __u32 offset, + void *buffer, __u32 buffer__szk) __ksym; + +/* Description + * Obtain a read-write pointer to the dynptr's data + * Returns + * Either a direct pointer to the dynptr data or a pointer to the user-provided + * buffer if unable to obtain a direct pointer + */ +extern void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr *ptr, __u32 offset, + void *buffer, __u32 buffer__szk) __ksym; + +#endif diff --git a/tools/testing/selftests/bpf/prog_tests/cls_redirect.c b/tools/testing/selftests/bpf/prog_tests/cls_redirect.c index 224f016b0a53..2a55f717fc07 100644 --- a/tools/testing/selftests/bpf/prog_tests/cls_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/cls_redirect.c @@ -13,6 +13,7 @@ #include "progs/test_cls_redirect.h" #include "test_cls_redirect.skel.h" +#include "test_cls_redirect_dynptr.skel.h" #include "test_cls_redirect_subprogs.skel.h" #define ENCAP_IP INADDR_LOOPBACK @@ -446,6 +447,28 @@ static void test_cls_redirect_common(struct bpf_program *prog) close_fds((int *)conns, sizeof(conns) / sizeof(conns[0][0])); } +static void test_cls_redirect_dynptr(void) +{ + struct test_cls_redirect_dynptr *skel; + int err; + + skel = test_cls_redirect_dynptr__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->rodata->ENCAPSULATION_IP = htonl(ENCAP_IP); + skel->rodata->ENCAPSULATION_PORT = htons(ENCAP_PORT); + + err = test_cls_redirect_dynptr__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + test_cls_redirect_common(skel->progs.cls_redirect); + +cleanup: + test_cls_redirect_dynptr__destroy(skel); +} + static void test_cls_redirect_inlined(void) { struct test_cls_redirect *skel; @@ -496,4 +519,6 @@ void test_cls_redirect(void) test_cls_redirect_inlined(); if (test__start_subtest("cls_redirect_subprogs")) test_cls_redirect_subprogs(); + if (test__start_subtest("cls_redirect_dynptr")) + test_cls_redirect_dynptr(); } diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index b99264ec0d9c..d176c34a7d2e 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -2,20 +2,32 @@ /* Copyright (c) 2022 Facebook */ #include +#include #include "dynptr_fail.skel.h" #include "dynptr_success.skel.h" -static const char * const success_tests[] = { - "test_read_write", - "test_data_slice", - "test_ringbuf", +enum test_setup_type { + SETUP_SYSCALL_SLEEP, + SETUP_SKB_PROG, }; -static void verify_success(const char *prog_name) +static struct { + const char *prog_name; + enum test_setup_type type; +} success_tests[] = { + {"test_read_write", SETUP_SYSCALL_SLEEP}, + {"test_dynptr_data", SETUP_SYSCALL_SLEEP}, + {"test_ringbuf", SETUP_SYSCALL_SLEEP}, + {"test_skb_readonly", SETUP_SKB_PROG}, + {"test_dynptr_skb_data", SETUP_SKB_PROG}, +}; + +static void verify_success(const char *prog_name, enum test_setup_type setup_type) { struct dynptr_success *skel; struct bpf_program *prog; struct bpf_link *link; + int err; skel = dynptr_success__open(); if (!ASSERT_OK_PTR(skel, "dynptr_success__open")) @@ -23,23 +35,53 @@ static void verify_success(const char *prog_name) skel->bss->pid = getpid(); - dynptr_success__load(skel); - if (!ASSERT_OK_PTR(skel, "dynptr_success__load")) - goto cleanup; - prog = bpf_object__find_program_by_name(skel->obj, prog_name); if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) goto cleanup; - link = bpf_program__attach(prog); - if (!ASSERT_OK_PTR(link, "bpf_program__attach")) + bpf_program__set_autoload(prog, true); + + err = dynptr_success__load(skel); + if (!ASSERT_OK(err, "dynptr_success__load")) goto cleanup; - usleep(1); + switch (setup_type) { + case SETUP_SYSCALL_SLEEP: + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "bpf_program__attach")) + goto cleanup; - ASSERT_EQ(skel->bss->err, 0, "err"); + usleep(1); + + bpf_link__destroy(link); + break; + case SETUP_SKB_PROG: + { + int prog_fd; + char buf[64]; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 1, + ); - bpf_link__destroy(link); + prog_fd = bpf_program__fd(prog); + if (!ASSERT_GE(prog_fd, 0, "prog_fd")) + goto cleanup; + + err = bpf_prog_test_run_opts(prog_fd, &topts); + + if (!ASSERT_OK(err, "test_run")) + goto cleanup; + + break; + } + } + + ASSERT_EQ(skel->bss->err, 0, "err"); cleanup: dynptr_success__destroy(skel); @@ -50,10 +92,10 @@ void test_dynptr(void) int i; for (i = 0; i < ARRAY_SIZE(success_tests); i++) { - if (!test__start_subtest(success_tests[i])) + if (!test__start_subtest(success_tests[i].prog_name)) continue; - verify_success(success_tests[i]); + verify_success(success_tests[i].prog_name, success_tests[i].type); } RUN_TESTS(dynptr_fail); diff --git a/tools/testing/selftests/bpf/prog_tests/l4lb_all.c b/tools/testing/selftests/bpf/prog_tests/l4lb_all.c index 9c1a18573ffd..1eab286b14fe 100644 --- a/tools/testing/selftests/bpf/prog_tests/l4lb_all.c +++ b/tools/testing/selftests/bpf/prog_tests/l4lb_all.c @@ -93,4 +93,6 @@ void test_l4lb_all(void) test_l4lb("test_l4lb.bpf.o"); if (test__start_subtest("l4lb_noinline")) test_l4lb("test_l4lb_noinline.bpf.o"); + if (test__start_subtest("l4lb_noinline_dynptr")) + test_l4lb("test_l4lb_noinline_dynptr.bpf.o"); } diff --git a/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c b/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c new file mode 100644 index 000000000000..daa952711d8f --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include "test_parse_tcp_hdr_opt.skel.h" +#include "test_parse_tcp_hdr_opt_dynptr.skel.h" +#include "test_tcp_hdr_options.h" + +struct test_pkt { + struct ipv6_packet pk6_v6; + u8 options[16]; +} __packed; + +struct test_pkt pkt = { + .pk6_v6.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6), + .pk6_v6.iph.nexthdr = IPPROTO_TCP, + .pk6_v6.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES), + .pk6_v6.tcp.urg_ptr = 123, + .pk6_v6.tcp.doff = 9, /* 16 bytes of options */ + + .options = { + TCPOPT_MSS, 4, 0x05, 0xB4, TCPOPT_NOP, TCPOPT_NOP, + 0, 6, 0xBB, 0xBB, 0xBB, 0xBB, TCPOPT_EOL + }, +}; + +static void test_parse_opt(void) +{ + struct test_parse_tcp_hdr_opt *skel; + struct bpf_program *prog; + char buf[128]; + int err; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt, + .data_size_in = sizeof(pkt), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 3, + ); + + skel = test_parse_tcp_hdr_opt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + pkt.options[6] = skel->rodata->tcp_hdr_opt_kind_tpr; + prog = skel->progs.xdp_ingress_v6; + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &topts); + ASSERT_OK(err, "ipv6 test_run"); + ASSERT_EQ(topts.retval, XDP_PASS, "ipv6 test_run retval"); + ASSERT_EQ(skel->bss->server_id, 0xBBBBBBBB, "server id"); + + test_parse_tcp_hdr_opt__destroy(skel); +} + +static void test_parse_opt_dynptr(void) +{ + struct test_parse_tcp_hdr_opt_dynptr *skel; + struct bpf_program *prog; + char buf[128]; + int err; + + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt, + .data_size_in = sizeof(pkt), + .data_out = buf, + .data_size_out = sizeof(buf), + .repeat = 3, + ); + + skel = test_parse_tcp_hdr_opt_dynptr__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) + return; + + pkt.options[6] = skel->rodata->tcp_hdr_opt_kind_tpr; + prog = skel->progs.xdp_ingress_v6; + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &topts); + ASSERT_OK(err, "ipv6 test_run"); + ASSERT_EQ(topts.retval, XDP_PASS, "ipv6 test_run retval"); + ASSERT_EQ(skel->bss->server_id, 0xBBBBBBBB, "server id"); + + test_parse_tcp_hdr_opt_dynptr__destroy(skel); +} + +void test_parse_tcp_hdr_opt(void) +{ + if (test__start_subtest("parse_tcp_hdr_opt")) + test_parse_opt(); + if (test__start_subtest("parse_tcp_hdr_opt_dynptr")) + test_parse_opt_dynptr(); +} diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c index d4cd9f873c14..fa3cac5488f5 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c @@ -4,11 +4,10 @@ #define IFINDEX_LO 1 #define XDP_FLAGS_REPLACE (1U << 4) -void serial_test_xdp_attach(void) +static void test_xdp_attach(const char *file) { __u32 duration = 0, id1, id2, id0 = 0, len; struct bpf_object *obj1, *obj2, *obj3; - const char *file = "./test_xdp.bpf.o"; struct bpf_prog_info info = {}; int err, fd1, fd2, fd3; LIBBPF_OPTS(bpf_xdp_attach_opts, opts); @@ -85,3 +84,11 @@ void serial_test_xdp_attach(void) out_1: bpf_object__close(obj1); } + +void serial_test_xdp_attach(void) +{ + if (test__start_subtest("xdp_attach")) + test_xdp_attach("./test_xdp.bpf.o"); + if (test__start_subtest("xdp_attach_dynptr")) + test_xdp_attach("./test_xdp_dynptr.bpf.o"); +} diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c index aa5b69354b91..20ce920d891d 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -5,7 +5,9 @@ #include #include #include +#include #include "bpf_misc.h" +#include "bpf_kfuncs.h" char _license[] SEC("license") = "GPL"; @@ -244,6 +246,27 @@ int data_slice_out_of_bounds_ringbuf(void *ctx) return 0; } +/* A data slice can't be accessed out of bounds */ +SEC("?tc") +__failure __msg("value is outside of the allowed memory range") +int data_slice_out_of_bounds_skb(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + /* this should fail */ + *(__u8*)(hdr + 1) = 1; + + return SK_PASS; +} + SEC("?raw_tp") __failure __msg("value is outside of the allowed memory range") int data_slice_out_of_bounds_map_value(void *ctx) @@ -399,7 +422,6 @@ int invalid_helper2(void *ctx) /* this should fail */ bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0, 0); - return 0; } @@ -1044,6 +1066,193 @@ int dynptr_read_into_slot(void *ctx) return 0; } +/* bpf_dynptr_slice()s are read-only and cannot be written to */ +SEC("?tc") +__failure __msg("R0 cannot write into rdonly_mem") +int skb_invalid_slice_write(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return SK_PASS; +} + +/* The read-only data slice is invalidated whenever a helper changes packet data */ +SEC("?tc") +__failure __msg("invalid mem access 'scalar'") +int skb_invalid_data_slice1(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + val = hdr->h_proto; + + if (bpf_skb_pull_data(skb, skb->len)) + return SK_DROP; + + /* this should fail */ + val = hdr->h_proto; + + return SK_PASS; +} + +/* The read-write data slice is invalidated whenever a helper changes packet data */ +SEC("?tc") +__failure __msg("invalid mem access 'scalar'") +int skb_invalid_data_slice2(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + hdr->h_proto = 123; + + if (bpf_skb_pull_data(skb, skb->len)) + return SK_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return SK_PASS; +} + +/* The read-only data slice is invalidated whenever bpf_dynptr_write() is called */ +SEC("?tc") +__failure __msg("invalid mem access 'scalar'") +int skb_invalid_data_slice3(struct __sk_buff *skb) +{ + char write_data[64] = "hello there, world!!"; + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + val = hdr->h_proto; + + bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); + + /* this should fail */ + val = hdr->h_proto; + + return SK_PASS; +} + +/* The read-write data slice is invalidated whenever bpf_dynptr_write() is called */ +SEC("?tc") +__failure __msg("invalid mem access 'scalar'") +int skb_invalid_data_slice4(struct __sk_buff *skb) +{ + char write_data[64] = "hello there, world!!"; + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + hdr->h_proto = 123; + + bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); + + /* this should fail */ + hdr->h_proto = 1; + + return SK_PASS; +} + +/* The read-only data slice is invalidated whenever a helper changes packet data */ +SEC("?xdp") +__failure __msg("invalid mem access 'scalar'") +int xdp_invalid_data_slice1(struct xdp_md *xdp) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + val = hdr->h_proto; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr))) + return XDP_DROP; + + /* this should fail */ + val = hdr->h_proto; + + return XDP_PASS; +} + +/* The read-write data slice is invalidated whenever a helper changes packet data */ +SEC("?xdp") +__failure __msg("invalid mem access 'scalar'") +int xdp_invalid_data_slice2(struct xdp_md *xdp) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + if (!hdr) + return SK_DROP; + + hdr->h_proto = 9; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr))) + return XDP_DROP; + + /* this should fail */ + hdr->h_proto = 1; + + return XDP_PASS; +} + +/* Only supported prog type can create skb-type dynptrs */ +SEC("?raw_tp") +__failure __msg("calling kernel function bpf_dynptr_from_skb is not allowed") +int skb_invalid_ctx(void *ctx) +{ + struct bpf_dynptr ptr; + + /* this should fail */ + bpf_dynptr_from_skb(ctx, 0, &ptr); + + return 0; +} + /* Reject writes to dynptr slot for uninit arg */ SEC("?raw_tp") __failure __msg("potential write to dynptr at off=-16") @@ -1061,6 +1270,61 @@ int uninit_write_into_slot(void *ctx) return 0; } +/* Only supported prog type can create xdp-type dynptrs */ +SEC("?raw_tp") +__failure __msg("calling kernel function bpf_dynptr_from_xdp is not allowed") +int xdp_invalid_ctx(void *ctx) +{ + struct bpf_dynptr ptr; + + /* this should fail */ + bpf_dynptr_from_xdp(ctx, 0, &ptr); + + return 0; +} + +__u32 hdr_size = sizeof(struct ethhdr); +/* Can't pass in variable-sized len to bpf_dynptr_slice */ +SEC("?tc") +__failure __msg("unbounded memory access") +int dynptr_slice_var_len1(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + struct ethhdr *hdr; + char buffer[sizeof(*hdr)] = {}; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + /* this should fail */ + hdr = bpf_dynptr_slice(&ptr, 0, buffer, hdr_size); + if (!hdr) + return SK_DROP; + + return SK_PASS; +} + +/* Can't pass in variable-sized len to bpf_dynptr_slice */ +SEC("?tc") +__failure __msg("must be a known constant") +int dynptr_slice_var_len2(struct __sk_buff *skb) +{ + char buffer[sizeof(struct ethhdr)] = {}; + struct bpf_dynptr ptr; + struct ethhdr *hdr; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + if (hdr_size <= sizeof(buffer)) { + /* this should fail */ + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, hdr_size); + if (!hdr) + return SK_DROP; + hdr->h_proto = 12; + } + + return SK_PASS; +} + static int callback(__u32 index, void *data) { *(__u32 *)data = 123; @@ -1092,3 +1356,24 @@ int invalid_data_slices(void *ctx) return 0; } + +/* Program types that don't allow writes to packet data should fail if + * bpf_dynptr_slice_rdwr is called + */ +SEC("cgroup_skb/ingress") +__failure __msg("the prog does not allow writes to packet data") +int invalid_slice_rdwr_rdonly(struct __sk_buff *skb) +{ + char buffer[sizeof(struct ethhdr)] = {}; + struct bpf_dynptr ptr; + struct ethhdr *hdr; + + bpf_dynptr_from_skb(skb, 0, &ptr); + + /* this should fail since cgroup_skb doesn't allow + * changing packet data + */ + hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c index 35db7c6c1fc7..c8358a7c7924 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_success.c +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c @@ -5,6 +5,7 @@ #include #include #include "bpf_misc.h" +#include "bpf_kfuncs.h" #include "errno.h" char _license[] SEC("license") = "GPL"; @@ -30,7 +31,7 @@ struct { __type(value, __u32); } array_map SEC(".maps"); -SEC("tp/syscalls/sys_enter_nanosleep") +SEC("?tp/syscalls/sys_enter_nanosleep") int test_read_write(void *ctx) { char write_data[64] = "hello there, world!!"; @@ -61,8 +62,8 @@ int test_read_write(void *ctx) return 0; } -SEC("tp/syscalls/sys_enter_nanosleep") -int test_data_slice(void *ctx) +SEC("?tp/syscalls/sys_enter_nanosleep") +int test_dynptr_data(void *ctx) { __u32 key = 0, val = 235, *map_val; struct bpf_dynptr ptr; @@ -131,7 +132,7 @@ static int ringbuf_callback(__u32 index, void *data) return 0; } -SEC("tp/syscalls/sys_enter_nanosleep") +SEC("?tp/syscalls/sys_enter_nanosleep") int test_ringbuf(void *ctx) { struct bpf_dynptr ptr; @@ -163,3 +164,49 @@ int test_ringbuf(void *ctx) bpf_ringbuf_discard_dynptr(&ptr, 0); return 0; } + +SEC("?cgroup_skb/egress") +int test_skb_readonly(struct __sk_buff *skb) +{ + __u8 write_data[2] = {1, 2}; + struct bpf_dynptr ptr; + __u64 *data; + int ret; + + if (bpf_dynptr_from_skb(skb, 0, &ptr)) { + err = 1; + return 1; + } + + /* since cgroup skbs are read only, writes should fail */ + ret = bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); + if (ret != -EINVAL) { + err = 2; + return 1; + } + + return 1; +} + +SEC("?cgroup_skb/egress") +int test_dynptr_skb_data(struct __sk_buff *skb) +{ + __u8 write_data[2] = {1, 2}; + struct bpf_dynptr ptr; + __u64 *data; + int ret; + + if (bpf_dynptr_from_skb(skb, 0, &ptr)) { + err = 1; + return 1; + } + + /* This should return NULL. Must use bpf_dynptr_slice API */ + data = bpf_dynptr_data(&ptr, 0, 1); + if (data) { + err = 2; + return 1; + } + + return 1; +} diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c b/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c new file mode 100644 index 000000000000..f45a7095de7a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c @@ -0,0 +1,980 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +// Copyright (c) 2019, 2020 Cloudflare + +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "test_cls_redirect.h" +#include "bpf_kfuncs.h" + +#define offsetofend(TYPE, MEMBER) \ + (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER))) + +#define IP_OFFSET_MASK (0x1FFF) +#define IP_MF (0x2000) + +char _license[] SEC("license") = "Dual BSD/GPL"; + +/** + * Destination port and IP used for UDP encapsulation. + */ +volatile const __be16 ENCAPSULATION_PORT; +volatile const __be32 ENCAPSULATION_IP; + +typedef struct { + uint64_t processed_packets_total; + uint64_t l3_protocol_packets_total_ipv4; + uint64_t l3_protocol_packets_total_ipv6; + uint64_t l4_protocol_packets_total_tcp; + uint64_t l4_protocol_packets_total_udp; + uint64_t accepted_packets_total_syn; + uint64_t accepted_packets_total_syn_cookies; + uint64_t accepted_packets_total_last_hop; + uint64_t accepted_packets_total_icmp_echo_request; + uint64_t accepted_packets_total_established; + uint64_t forwarded_packets_total_gue; + uint64_t forwarded_packets_total_gre; + + uint64_t errors_total_unknown_l3_proto; + uint64_t errors_total_unknown_l4_proto; + uint64_t errors_total_malformed_ip; + uint64_t errors_total_fragmented_ip; + uint64_t errors_total_malformed_icmp; + uint64_t errors_total_unwanted_icmp; + uint64_t errors_total_malformed_icmp_pkt_too_big; + uint64_t errors_total_malformed_tcp; + uint64_t errors_total_malformed_udp; + uint64_t errors_total_icmp_echo_replies; + uint64_t errors_total_malformed_encapsulation; + uint64_t errors_total_encap_adjust_failed; + uint64_t errors_total_encap_buffer_too_small; + uint64_t errors_total_redirect_loop; + uint64_t errors_total_encap_mtu_violate; +} metrics_t; + +typedef enum { + INVALID = 0, + UNKNOWN, + ECHO_REQUEST, + SYN, + SYN_COOKIE, + ESTABLISHED, +} verdict_t; + +typedef struct { + uint16_t src, dst; +} flow_ports_t; + +_Static_assert( + sizeof(flow_ports_t) != + offsetofend(struct bpf_sock_tuple, ipv4.dport) - + offsetof(struct bpf_sock_tuple, ipv4.sport) - 1, + "flow_ports_t must match sport and dport in struct bpf_sock_tuple"); +_Static_assert( + sizeof(flow_ports_t) != + offsetofend(struct bpf_sock_tuple, ipv6.dport) - + offsetof(struct bpf_sock_tuple, ipv6.sport) - 1, + "flow_ports_t must match sport and dport in struct bpf_sock_tuple"); + +struct iphdr_info { + void *hdr; + __u64 len; +}; + +typedef int ret_t; + +/* This is a bit of a hack. We need a return value which allows us to + * indicate that the regular flow of the program should continue, + * while allowing functions to use XDP_PASS and XDP_DROP, etc. + */ +static const ret_t CONTINUE_PROCESSING = -1; + +/* Convenience macro to call functions which return ret_t. + */ +#define MAYBE_RETURN(x) \ + do { \ + ret_t __ret = x; \ + if (__ret != CONTINUE_PROCESSING) \ + return __ret; \ + } while (0) + +static bool ipv4_is_fragment(const struct iphdr *ip) +{ + uint16_t frag_off = ip->frag_off & bpf_htons(IP_OFFSET_MASK); + return (ip->frag_off & bpf_htons(IP_MF)) != 0 || frag_off > 0; +} + +static int pkt_parse_ipv4(struct bpf_dynptr *dynptr, __u64 *offset, struct iphdr *iphdr) +{ + if (bpf_dynptr_read(iphdr, sizeof(*iphdr), dynptr, *offset, 0)) + return -1; + + *offset += sizeof(*iphdr); + + if (iphdr->ihl < 5) + return -1; + + /* skip ipv4 options */ + *offset += (iphdr->ihl - 5) * 4; + + return 0; +} + +/* Parse the L4 ports from a packet, assuming a layout like TCP or UDP. */ +static bool pkt_parse_icmp_l4_ports(struct bpf_dynptr *dynptr, __u64 *offset, flow_ports_t *ports) +{ + if (bpf_dynptr_read(ports, sizeof(*ports), dynptr, *offset, 0)) + return false; + + *offset += sizeof(*ports); + + /* Ports in the L4 headers are reversed, since we are parsing an ICMP + * payload which is going towards the eyeball. + */ + uint16_t dst = ports->src; + ports->src = ports->dst; + ports->dst = dst; + return true; +} + +static uint16_t pkt_checksum_fold(uint32_t csum) +{ + /* The highest reasonable value for an IPv4 header + * checksum requires two folds, so we just do that always. + */ + csum = (csum & 0xffff) + (csum >> 16); + csum = (csum & 0xffff) + (csum >> 16); + return (uint16_t)~csum; +} + +static void pkt_ipv4_checksum(struct iphdr *iph) +{ + iph->check = 0; + + /* An IP header without options is 20 bytes. Two of those + * are the checksum, which we always set to zero. Hence, + * the maximum accumulated value is 18 / 2 * 0xffff = 0x8fff7, + * which fits in 32 bit. + */ + _Static_assert(sizeof(struct iphdr) == 20, "iphdr must be 20 bytes"); + uint32_t acc = 0; + uint16_t *ipw = (uint16_t *)iph; + + for (size_t i = 0; i < sizeof(struct iphdr) / 2; i++) + acc += ipw[i]; + + iph->check = pkt_checksum_fold(acc); +} + +static bool pkt_skip_ipv6_extension_headers(struct bpf_dynptr *dynptr, __u64 *offset, + const struct ipv6hdr *ipv6, uint8_t *upper_proto, + bool *is_fragment) +{ + /* We understand five extension headers. + * https://tools.ietf.org/html/rfc8200#section-4.1 states that all + * headers should occur once, except Destination Options, which may + * occur twice. Hence we give up after 6 headers. + */ + struct { + uint8_t next; + uint8_t len; + } exthdr = { + .next = ipv6->nexthdr, + }; + *is_fragment = false; + + for (int i = 0; i < 6; i++) { + switch (exthdr.next) { + case IPPROTO_FRAGMENT: + *is_fragment = true; + /* NB: We don't check that hdrlen == 0 as per spec. */ + /* fallthrough; */ + + case IPPROTO_HOPOPTS: + case IPPROTO_ROUTING: + case IPPROTO_DSTOPTS: + case IPPROTO_MH: + if (bpf_dynptr_read(&exthdr, sizeof(exthdr), dynptr, *offset, 0)) + return false; + + /* hdrlen is in 8-octet units, and excludes the first 8 octets. */ + *offset += (exthdr.len + 1) * 8; + + /* Decode next header */ + break; + + default: + /* The next header is not one of the known extension + * headers, treat it as the upper layer header. + * + * This handles IPPROTO_NONE. + * + * Encapsulating Security Payload (50) and Authentication + * Header (51) also end up here (and will trigger an + * unknown proto error later). They have a custom header + * format and seem too esoteric to care about. + */ + *upper_proto = exthdr.next; + return true; + } + } + + /* We never found an upper layer header. */ + return false; +} + +static int pkt_parse_ipv6(struct bpf_dynptr *dynptr, __u64 *offset, struct ipv6hdr *ipv6, + uint8_t *proto, bool *is_fragment) +{ + if (bpf_dynptr_read(ipv6, sizeof(*ipv6), dynptr, *offset, 0)) + return -1; + + *offset += sizeof(*ipv6); + + if (!pkt_skip_ipv6_extension_headers(dynptr, offset, ipv6, proto, is_fragment)) + return -1; + + return 0; +} + +/* Global metrics, per CPU + */ +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 1); + __type(key, unsigned int); + __type(value, metrics_t); +} metrics_map SEC(".maps"); + +static metrics_t *get_global_metrics(void) +{ + uint64_t key = 0; + return bpf_map_lookup_elem(&metrics_map, &key); +} + +static ret_t accept_locally(struct __sk_buff *skb, encap_headers_t *encap) +{ + const int payload_off = + sizeof(*encap) + + sizeof(struct in_addr) * encap->unigue.hop_count; + int32_t encap_overhead = payload_off - sizeof(struct ethhdr); + + /* Changing the ethertype if the encapsulated packet is ipv6 */ + if (encap->gue.proto_ctype == IPPROTO_IPV6) + encap->eth.h_proto = bpf_htons(ETH_P_IPV6); + + if (bpf_skb_adjust_room(skb, -encap_overhead, BPF_ADJ_ROOM_MAC, + BPF_F_ADJ_ROOM_FIXED_GSO | + BPF_F_ADJ_ROOM_NO_CSUM_RESET) || + bpf_csum_level(skb, BPF_CSUM_LEVEL_DEC)) + return TC_ACT_SHOT; + + return bpf_redirect(skb->ifindex, BPF_F_INGRESS); +} + +static ret_t forward_with_gre(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + encap_headers_t *encap, struct in_addr *next_hop, + metrics_t *metrics) +{ + const int payload_off = + sizeof(*encap) + + sizeof(struct in_addr) * encap->unigue.hop_count; + int32_t encap_overhead = + payload_off - sizeof(struct ethhdr) - sizeof(struct iphdr); + int32_t delta = sizeof(struct gre_base_hdr) - encap_overhead; + __u8 encap_buffer[sizeof(encap_gre_t)] = {}; + uint16_t proto = ETH_P_IP; + uint32_t mtu_len = 0; + encap_gre_t *encap_gre; + + metrics->forwarded_packets_total_gre++; + + /* Loop protection: the inner packet's TTL is decremented as a safeguard + * against any forwarding loop. As the only interesting field is the TTL + * hop limit for IPv6, it is easier to use bpf_skb_load_bytes/bpf_skb_store_bytes + * as they handle the split packets if needed (no need for the data to be + * in the linear section). + */ + if (encap->gue.proto_ctype == IPPROTO_IPV6) { + proto = ETH_P_IPV6; + uint8_t ttl; + int rc; + + rc = bpf_skb_load_bytes( + skb, payload_off + offsetof(struct ipv6hdr, hop_limit), + &ttl, 1); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (ttl == 0) { + metrics->errors_total_redirect_loop++; + return TC_ACT_SHOT; + } + + ttl--; + rc = bpf_skb_store_bytes( + skb, payload_off + offsetof(struct ipv6hdr, hop_limit), + &ttl, 1, 0); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + } else { + uint8_t ttl; + int rc; + + rc = bpf_skb_load_bytes( + skb, payload_off + offsetof(struct iphdr, ttl), &ttl, + 1); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (ttl == 0) { + metrics->errors_total_redirect_loop++; + return TC_ACT_SHOT; + } + + /* IPv4 also has a checksum to patch. While the TTL is only one byte, + * this function only works for 2 and 4 bytes arguments (the result is + * the same). + */ + rc = bpf_l3_csum_replace( + skb, payload_off + offsetof(struct iphdr, check), ttl, + ttl - 1, 2); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + ttl--; + rc = bpf_skb_store_bytes( + skb, payload_off + offsetof(struct iphdr, ttl), &ttl, 1, + 0); + if (rc != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + } + + if (bpf_check_mtu(skb, skb->ifindex, &mtu_len, delta, 0)) { + metrics->errors_total_encap_mtu_violate++; + return TC_ACT_SHOT; + } + + if (bpf_skb_adjust_room(skb, delta, BPF_ADJ_ROOM_NET, + BPF_F_ADJ_ROOM_FIXED_GSO | + BPF_F_ADJ_ROOM_NO_CSUM_RESET) || + bpf_csum_level(skb, BPF_CSUM_LEVEL_INC)) { + metrics->errors_total_encap_adjust_failed++; + return TC_ACT_SHOT; + } + + if (bpf_skb_pull_data(skb, sizeof(encap_gre_t))) { + metrics->errors_total_encap_buffer_too_small++; + return TC_ACT_SHOT; + } + + encap_gre = bpf_dynptr_slice_rdwr(dynptr, 0, encap_buffer, sizeof(encap_buffer)); + if (!encap_gre) { + metrics->errors_total_encap_buffer_too_small++; + return TC_ACT_SHOT; + } + + encap_gre->ip.protocol = IPPROTO_GRE; + encap_gre->ip.daddr = next_hop->s_addr; + encap_gre->ip.saddr = ENCAPSULATION_IP; + encap_gre->ip.tot_len = + bpf_htons(bpf_ntohs(encap_gre->ip.tot_len) + delta); + encap_gre->gre.flags = 0; + encap_gre->gre.protocol = bpf_htons(proto); + pkt_ipv4_checksum((void *)&encap_gre->ip); + + if (encap_gre == encap_buffer) + bpf_dynptr_write(dynptr, 0, encap_buffer, sizeof(encap_buffer), 0); + + return bpf_redirect(skb->ifindex, 0); +} + +static ret_t forward_to_next_hop(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + encap_headers_t *encap, struct in_addr *next_hop, + metrics_t *metrics) +{ + /* swap L2 addresses */ + /* This assumes that packets are received from a router. + * So just swapping the MAC addresses here will make the packet go back to + * the router, which will send it to the appropriate machine. + */ + unsigned char temp[ETH_ALEN]; + memcpy(temp, encap->eth.h_dest, sizeof(temp)); + memcpy(encap->eth.h_dest, encap->eth.h_source, + sizeof(encap->eth.h_dest)); + memcpy(encap->eth.h_source, temp, sizeof(encap->eth.h_source)); + + if (encap->unigue.next_hop == encap->unigue.hop_count - 1 && + encap->unigue.last_hop_gre) { + return forward_with_gre(skb, dynptr, encap, next_hop, metrics); + } + + metrics->forwarded_packets_total_gue++; + uint32_t old_saddr = encap->ip.saddr; + encap->ip.saddr = encap->ip.daddr; + encap->ip.daddr = next_hop->s_addr; + if (encap->unigue.next_hop < encap->unigue.hop_count) { + encap->unigue.next_hop++; + } + + /* Remove ip->saddr, add next_hop->s_addr */ + const uint64_t off = offsetof(typeof(*encap), ip.check); + int ret = bpf_l3_csum_replace(skb, off, old_saddr, next_hop->s_addr, 4); + if (ret < 0) { + return TC_ACT_SHOT; + } + + return bpf_redirect(skb->ifindex, 0); +} + +static ret_t skip_next_hops(__u64 *offset, int n) +{ + __u32 res; + switch (n) { + case 1: + *offset += sizeof(struct in_addr); + case 0: + return CONTINUE_PROCESSING; + + default: + return TC_ACT_SHOT; + } +} + +/* Get the next hop from the GLB header. + * + * Sets next_hop->s_addr to 0 if there are no more hops left. + * pkt is positioned just after the variable length GLB header + * iff the call is successful. + */ +static ret_t get_next_hop(struct bpf_dynptr *dynptr, __u64 *offset, encap_headers_t *encap, + struct in_addr *next_hop) +{ + if (encap->unigue.next_hop > encap->unigue.hop_count) + return TC_ACT_SHOT; + + /* Skip "used" next hops. */ + MAYBE_RETURN(skip_next_hops(offset, encap->unigue.next_hop)); + + if (encap->unigue.next_hop == encap->unigue.hop_count) { + /* No more next hops, we are at the end of the GLB header. */ + next_hop->s_addr = 0; + return CONTINUE_PROCESSING; + } + + if (bpf_dynptr_read(next_hop, sizeof(*next_hop), dynptr, *offset, 0)) + return TC_ACT_SHOT; + + *offset += sizeof(*next_hop); + + /* Skip the remainig next hops (may be zero). */ + return skip_next_hops(offset, encap->unigue.hop_count - encap->unigue.next_hop - 1); +} + +/* Fill a bpf_sock_tuple to be used with the socket lookup functions. + * This is a kludge that let's us work around verifier limitations: + * + * fill_tuple(&t, foo, sizeof(struct iphdr), 123, 321) + * + * clang will substitue a costant for sizeof, which allows the verifier + * to track it's value. Based on this, it can figure out the constant + * return value, and calling code works while still being "generic" to + * IPv4 and IPv6. + */ +static uint64_t fill_tuple(struct bpf_sock_tuple *tuple, void *iph, + uint64_t iphlen, uint16_t sport, uint16_t dport) +{ + switch (iphlen) { + case sizeof(struct iphdr): { + struct iphdr *ipv4 = (struct iphdr *)iph; + tuple->ipv4.daddr = ipv4->daddr; + tuple->ipv4.saddr = ipv4->saddr; + tuple->ipv4.sport = sport; + tuple->ipv4.dport = dport; + return sizeof(tuple->ipv4); + } + + case sizeof(struct ipv6hdr): { + struct ipv6hdr *ipv6 = (struct ipv6hdr *)iph; + memcpy(&tuple->ipv6.daddr, &ipv6->daddr, + sizeof(tuple->ipv6.daddr)); + memcpy(&tuple->ipv6.saddr, &ipv6->saddr, + sizeof(tuple->ipv6.saddr)); + tuple->ipv6.sport = sport; + tuple->ipv6.dport = dport; + return sizeof(tuple->ipv6); + } + + default: + return 0; + } +} + +static verdict_t classify_tcp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, + uint64_t tuplen, void *iph, struct tcphdr *tcp) +{ + struct bpf_sock *sk = + bpf_skc_lookup_tcp(skb, tuple, tuplen, BPF_F_CURRENT_NETNS, 0); + + if (sk == NULL) + return UNKNOWN; + + if (sk->state != BPF_TCP_LISTEN) { + bpf_sk_release(sk); + return ESTABLISHED; + } + + if (iph != NULL && tcp != NULL) { + /* Kludge: we've run out of arguments, but need the length of the ip header. */ + uint64_t iphlen = sizeof(struct iphdr); + + if (tuplen == sizeof(tuple->ipv6)) + iphlen = sizeof(struct ipv6hdr); + + if (bpf_tcp_check_syncookie(sk, iph, iphlen, tcp, + sizeof(*tcp)) == 0) { + bpf_sk_release(sk); + return SYN_COOKIE; + } + } + + bpf_sk_release(sk); + return UNKNOWN; +} + +static verdict_t classify_udp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, uint64_t tuplen) +{ + struct bpf_sock *sk = + bpf_sk_lookup_udp(skb, tuple, tuplen, BPF_F_CURRENT_NETNS, 0); + + if (sk == NULL) + return UNKNOWN; + + if (sk->state == BPF_TCP_ESTABLISHED) { + bpf_sk_release(sk); + return ESTABLISHED; + } + + bpf_sk_release(sk); + return UNKNOWN; +} + +static verdict_t classify_icmp(struct __sk_buff *skb, uint8_t proto, struct bpf_sock_tuple *tuple, + uint64_t tuplen, metrics_t *metrics) +{ + switch (proto) { + case IPPROTO_TCP: + return classify_tcp(skb, tuple, tuplen, NULL, NULL); + + case IPPROTO_UDP: + return classify_udp(skb, tuple, tuplen); + + default: + metrics->errors_total_malformed_icmp++; + return INVALID; + } +} + +static verdict_t process_icmpv4(struct __sk_buff *skb, struct bpf_dynptr *dynptr, __u64 *offset, + metrics_t *metrics) +{ + struct icmphdr icmp; + struct iphdr ipv4; + + if (bpf_dynptr_read(&icmp, sizeof(icmp), dynptr, *offset, 0)) { + metrics->errors_total_malformed_icmp++; + return INVALID; + } + + *offset += sizeof(icmp); + + /* We should never receive encapsulated echo replies. */ + if (icmp.type == ICMP_ECHOREPLY) { + metrics->errors_total_icmp_echo_replies++; + return INVALID; + } + + if (icmp.type == ICMP_ECHO) + return ECHO_REQUEST; + + if (icmp.type != ICMP_DEST_UNREACH || icmp.code != ICMP_FRAG_NEEDED) { + metrics->errors_total_unwanted_icmp++; + return INVALID; + } + + if (pkt_parse_ipv4(dynptr, offset, &ipv4)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + /* The source address in the outer IP header is from the entity that + * originated the ICMP message. Use the original IP header to restore + * the correct flow tuple. + */ + struct bpf_sock_tuple tuple; + tuple.ipv4.saddr = ipv4.daddr; + tuple.ipv4.daddr = ipv4.saddr; + + if (!pkt_parse_icmp_l4_ports(dynptr, offset, (flow_ports_t *)&tuple.ipv4.sport)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + return classify_icmp(skb, ipv4.protocol, &tuple, + sizeof(tuple.ipv4), metrics); +} + +static verdict_t process_icmpv6(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct ipv6hdr ipv6; + struct icmp6hdr icmp6; + bool is_fragment; + uint8_t l4_proto; + + if (bpf_dynptr_read(&icmp6, sizeof(icmp6), dynptr, *offset, 0)) { + metrics->errors_total_malformed_icmp++; + return INVALID; + } + + /* We should never receive encapsulated echo replies. */ + if (icmp6.icmp6_type == ICMPV6_ECHO_REPLY) { + metrics->errors_total_icmp_echo_replies++; + return INVALID; + } + + if (icmp6.icmp6_type == ICMPV6_ECHO_REQUEST) { + return ECHO_REQUEST; + } + + if (icmp6.icmp6_type != ICMPV6_PKT_TOOBIG) { + metrics->errors_total_unwanted_icmp++; + return INVALID; + } + + if (pkt_parse_ipv6(dynptr, offset, &ipv6, &l4_proto, &is_fragment)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + if (is_fragment) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + /* Swap source and dest addresses. */ + memcpy(&tuple.ipv6.saddr, &ipv6.daddr, sizeof(tuple.ipv6.saddr)); + memcpy(&tuple.ipv6.daddr, &ipv6.saddr, sizeof(tuple.ipv6.daddr)); + + if (!pkt_parse_icmp_l4_ports(dynptr, offset, (flow_ports_t *)&tuple.ipv6.sport)) { + metrics->errors_total_malformed_icmp_pkt_too_big++; + return INVALID; + } + + return classify_icmp(skb, l4_proto, &tuple, sizeof(tuple.ipv6), + metrics); +} + +static verdict_t process_tcp(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + struct iphdr_info *info, metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct tcphdr tcp; + uint64_t tuplen; + + metrics->l4_protocol_packets_total_tcp++; + + if (bpf_dynptr_read(&tcp, sizeof(tcp), dynptr, *offset, 0)) { + metrics->errors_total_malformed_tcp++; + return INVALID; + } + + *offset += sizeof(tcp); + + if (tcp.syn) + return SYN; + + tuplen = fill_tuple(&tuple, info->hdr, info->len, tcp.source, tcp.dest); + return classify_tcp(skb, &tuple, tuplen, info->hdr, &tcp); +} + +static verdict_t process_udp(struct bpf_dynptr *dynptr, __u64 *offset, struct __sk_buff *skb, + struct iphdr_info *info, metrics_t *metrics) +{ + struct bpf_sock_tuple tuple; + struct udphdr udph; + uint64_t tuplen; + + metrics->l4_protocol_packets_total_udp++; + + if (bpf_dynptr_read(&udph, sizeof(udph), dynptr, *offset, 0)) { + metrics->errors_total_malformed_udp++; + return INVALID; + } + *offset += sizeof(udph); + + tuplen = fill_tuple(&tuple, info->hdr, info->len, udph.source, udph.dest); + return classify_udp(skb, &tuple, tuplen); +} + +static verdict_t process_ipv4(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + __u64 *offset, metrics_t *metrics) +{ + struct iphdr ipv4; + struct iphdr_info info = { + .hdr = &ipv4, + .len = sizeof(ipv4), + }; + + metrics->l3_protocol_packets_total_ipv4++; + + if (pkt_parse_ipv4(dynptr, offset, &ipv4)) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv4.version != 4) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv4_is_fragment(&ipv4)) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + switch (ipv4.protocol) { + case IPPROTO_ICMP: + return process_icmpv4(skb, dynptr, offset, metrics); + + case IPPROTO_TCP: + return process_tcp(dynptr, offset, skb, &info, metrics); + + case IPPROTO_UDP: + return process_udp(dynptr, offset, skb, &info, metrics); + + default: + metrics->errors_total_unknown_l4_proto++; + return INVALID; + } +} + +static verdict_t process_ipv6(struct __sk_buff *skb, struct bpf_dynptr *dynptr, + __u64 *offset, metrics_t *metrics) +{ + struct ipv6hdr ipv6; + struct iphdr_info info = { + .hdr = &ipv6, + .len = sizeof(ipv6), + }; + uint8_t l4_proto; + bool is_fragment; + + metrics->l3_protocol_packets_total_ipv6++; + + if (pkt_parse_ipv6(dynptr, offset, &ipv6, &l4_proto, &is_fragment)) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (ipv6.version != 6) { + metrics->errors_total_malformed_ip++; + return INVALID; + } + + if (is_fragment) { + metrics->errors_total_fragmented_ip++; + return INVALID; + } + + switch (l4_proto) { + case IPPROTO_ICMPV6: + return process_icmpv6(dynptr, offset, skb, metrics); + + case IPPROTO_TCP: + return process_tcp(dynptr, offset, skb, &info, metrics); + + case IPPROTO_UDP: + return process_udp(dynptr, offset, skb, &info, metrics); + + default: + metrics->errors_total_unknown_l4_proto++; + return INVALID; + } +} + +SEC("tc") +int cls_redirect(struct __sk_buff *skb) +{ + __u8 encap_buffer[sizeof(encap_headers_t)] = {}; + struct bpf_dynptr dynptr; + struct in_addr next_hop; + /* Tracks offset of the dynptr. This will be unnecessary once + * bpf_dynptr_advance() is available. + */ + __u64 off = 0; + ret_t ret; + + bpf_dynptr_from_skb(skb, 0, &dynptr); + + metrics_t *metrics = get_global_metrics(); + if (metrics == NULL) + return TC_ACT_SHOT; + + metrics->processed_packets_total++; + + /* Pass bogus packets as long as we're not sure they're + * destined for us. + */ + if (skb->protocol != bpf_htons(ETH_P_IP)) + return TC_ACT_OK; + + encap_headers_t *encap; + + /* Make sure that all encapsulation headers are available in + * the linear portion of the skb. This makes it easy to manipulate them. + */ + if (bpf_skb_pull_data(skb, sizeof(*encap))) + return TC_ACT_OK; + + encap = bpf_dynptr_slice_rdwr(&dynptr, 0, encap_buffer, sizeof(encap_buffer)); + if (!encap) + return TC_ACT_OK; + + off += sizeof(*encap); + + if (encap->ip.ihl != 5) + /* We never have any options. */ + return TC_ACT_OK; + + if (encap->ip.daddr != ENCAPSULATION_IP || + encap->ip.protocol != IPPROTO_UDP) + return TC_ACT_OK; + + /* TODO Check UDP length? */ + if (encap->udp.dest != ENCAPSULATION_PORT) + return TC_ACT_OK; + + /* We now know that the packet is destined to us, we can + * drop bogus ones. + */ + if (ipv4_is_fragment((void *)&encap->ip)) { + metrics->errors_total_fragmented_ip++; + return TC_ACT_SHOT; + } + + if (encap->gue.variant != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.control != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.flags != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->gue.hlen != + sizeof(encap->unigue) / 4 + encap->unigue.hop_count) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->unigue.version != 0) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + + if (encap->unigue.reserved != 0) + return TC_ACT_SHOT; + + MAYBE_RETURN(get_next_hop(&dynptr, &off, encap, &next_hop)); + + if (next_hop.s_addr == 0) { + metrics->accepted_packets_total_last_hop++; + return accept_locally(skb, encap); + } + + verdict_t verdict; + switch (encap->gue.proto_ctype) { + case IPPROTO_IPIP: + verdict = process_ipv4(skb, &dynptr, &off, metrics); + break; + + case IPPROTO_IPV6: + verdict = process_ipv6(skb, &dynptr, &off, metrics); + break; + + default: + metrics->errors_total_unknown_l3_proto++; + return TC_ACT_SHOT; + } + + switch (verdict) { + case INVALID: + /* metrics have already been bumped */ + return TC_ACT_SHOT; + + case UNKNOWN: + return forward_to_next_hop(skb, &dynptr, encap, &next_hop, metrics); + + case ECHO_REQUEST: + metrics->accepted_packets_total_icmp_echo_request++; + break; + + case SYN: + if (encap->unigue.forward_syn) { + return forward_to_next_hop(skb, &dynptr, encap, &next_hop, + metrics); + } + + metrics->accepted_packets_total_syn++; + break; + + case SYN_COOKIE: + metrics->accepted_packets_total_syn_cookies++; + break; + + case ESTABLISHED: + metrics->accepted_packets_total_established++; + break; + } + + ret = accept_locally(skb, encap); + + if (encap == encap_buffer) + bpf_dynptr_write(&dynptr, 0, encap_buffer, sizeof(encap_buffer), 0); + + return ret; +} diff --git a/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c b/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c new file mode 100644 index 000000000000..f997f5080748 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c @@ -0,0 +1,487 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2017 Facebook +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "test_iptunnel_common.h" +#include + +#include "bpf_kfuncs.h" + +static __always_inline __u32 rol32(__u32 word, unsigned int shift) +{ + return (word << shift) | (word >> ((-shift) & 31)); +} + +/* copy paste of jhash from kernel sources to make sure llvm + * can compile it into valid sequence of bpf instructions + */ +#define __jhash_mix(a, b, c) \ +{ \ + a -= c; a ^= rol32(c, 4); c += b; \ + b -= a; b ^= rol32(a, 6); a += c; \ + c -= b; c ^= rol32(b, 8); b += a; \ + a -= c; a ^= rol32(c, 16); c += b; \ + b -= a; b ^= rol32(a, 19); a += c; \ + c -= b; c ^= rol32(b, 4); b += a; \ +} + +#define __jhash_final(a, b, c) \ +{ \ + c ^= b; c -= rol32(b, 14); \ + a ^= c; a -= rol32(c, 11); \ + b ^= a; b -= rol32(a, 25); \ + c ^= b; c -= rol32(b, 16); \ + a ^= c; a -= rol32(c, 4); \ + b ^= a; b -= rol32(a, 14); \ + c ^= b; c -= rol32(b, 24); \ +} + +#define JHASH_INITVAL 0xdeadbeef + +typedef unsigned int u32; + +static __noinline u32 jhash(const void *key, u32 length, u32 initval) +{ + u32 a, b, c; + const unsigned char *k = key; + + a = b = c = JHASH_INITVAL + length + initval; + + while (length > 12) { + a += *(u32 *)(k); + b += *(u32 *)(k + 4); + c += *(u32 *)(k + 8); + __jhash_mix(a, b, c); + length -= 12; + k += 12; + } + switch (length) { + case 12: c += (u32)k[11]<<24; + case 11: c += (u32)k[10]<<16; + case 10: c += (u32)k[9]<<8; + case 9: c += k[8]; + case 8: b += (u32)k[7]<<24; + case 7: b += (u32)k[6]<<16; + case 6: b += (u32)k[5]<<8; + case 5: b += k[4]; + case 4: a += (u32)k[3]<<24; + case 3: a += (u32)k[2]<<16; + case 2: a += (u32)k[1]<<8; + case 1: a += k[0]; + __jhash_final(a, b, c); + case 0: /* Nothing left to add */ + break; + } + + return c; +} + +static __noinline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval) +{ + a += initval; + b += initval; + c += initval; + __jhash_final(a, b, c); + return c; +} + +static __noinline u32 jhash_2words(u32 a, u32 b, u32 initval) +{ + return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2)); +} + +#define PCKT_FRAGMENTED 65343 +#define IPV4_HDR_LEN_NO_OPT 20 +#define IPV4_PLUS_ICMP_HDR 28 +#define IPV6_PLUS_ICMP_HDR 48 +#define RING_SIZE 2 +#define MAX_VIPS 12 +#define MAX_REALS 5 +#define CTL_MAP_SIZE 16 +#define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE) +#define F_IPV6 (1 << 0) +#define F_HASH_NO_SRC_PORT (1 << 0) +#define F_ICMP (1 << 0) +#define F_SYN_SET (1 << 1) + +struct packet_description { + union { + __be32 src; + __be32 srcv6[4]; + }; + union { + __be32 dst; + __be32 dstv6[4]; + }; + union { + __u32 ports; + __u16 port16[2]; + }; + __u8 proto; + __u8 flags; +}; + +struct ctl_value { + union { + __u64 value; + __u32 ifindex; + __u8 mac[6]; + }; +}; + +struct vip_meta { + __u32 flags; + __u32 vip_num; +}; + +struct real_definition { + union { + __be32 dst; + __be32 dstv6[4]; + }; + __u8 flags; +}; + +struct vip_stats { + __u64 bytes; + __u64 pkts; +}; + +struct eth_hdr { + unsigned char eth_dest[ETH_ALEN]; + unsigned char eth_source[ETH_ALEN]; + unsigned short eth_proto; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, MAX_VIPS); + __type(key, struct vip); + __type(value, struct vip_meta); +} vip_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, CH_RINGS_SIZE); + __type(key, __u32); + __type(value, __u32); +} ch_rings SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, MAX_REALS); + __type(key, __u32); + __type(value, struct real_definition); +} reals SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, MAX_VIPS); + __type(key, __u32); + __type(value, struct vip_stats); +} stats SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, CTL_MAP_SIZE); + __type(key, __u32); + __type(value, struct ctl_value); +} ctl_array SEC(".maps"); + +static __noinline __u32 get_packet_hash(struct packet_description *pckt, bool ipv6) +{ + if (ipv6) + return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS), + pckt->ports, CH_RINGS_SIZE); + else + return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE); +} + +static __noinline bool get_packet_dst(struct real_definition **real, + struct packet_description *pckt, + struct vip_meta *vip_info, + bool is_ipv6) +{ + __u32 hash = get_packet_hash(pckt, is_ipv6); + __u32 key = RING_SIZE * vip_info->vip_num + hash % RING_SIZE; + __u32 *real_pos; + + if (hash != 0x358459b7 /* jhash of ipv4 packet */ && + hash != 0x2f4bc6bb /* jhash of ipv6 packet */) + return false; + + real_pos = bpf_map_lookup_elem(&ch_rings, &key); + if (!real_pos) + return false; + key = *real_pos; + *real = bpf_map_lookup_elem(&reals, &key); + if (!(*real)) + return false; + return true; +} + +static __noinline int parse_icmpv6(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + __u8 buffer[sizeof(struct ipv6hdr)] = {}; + struct icmp6hdr *icmp_hdr; + struct ipv6hdr *ip6h; + + icmp_hdr = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!icmp_hdr) + return TC_ACT_SHOT; + + if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG) + return TC_ACT_OK; + off += sizeof(struct icmp6hdr); + ip6h = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!ip6h) + return TC_ACT_SHOT; + pckt->proto = ip6h->nexthdr; + pckt->flags |= F_ICMP; + memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16); + memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16); + return TC_ACT_UNSPEC; +} + +static __noinline int parse_icmp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + __u8 buffer_icmp[sizeof(struct iphdr)] = {}; + __u8 buffer_ip[sizeof(struct iphdr)] = {}; + struct icmphdr *icmp_hdr; + struct iphdr *iph; + + icmp_hdr = bpf_dynptr_slice(skb_ptr, off, buffer_icmp, sizeof(buffer_icmp)); + if (!icmp_hdr) + return TC_ACT_SHOT; + if (icmp_hdr->type != ICMP_DEST_UNREACH || + icmp_hdr->code != ICMP_FRAG_NEEDED) + return TC_ACT_OK; + off += sizeof(struct icmphdr); + iph = bpf_dynptr_slice(skb_ptr, off, buffer_ip, sizeof(buffer_ip)); + if (!iph || iph->ihl != 5) + return TC_ACT_SHOT; + pckt->proto = iph->protocol; + pckt->flags |= F_ICMP; + pckt->src = iph->daddr; + pckt->dst = iph->saddr; + return TC_ACT_UNSPEC; +} + +static __noinline bool parse_udp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + __u8 buffer[sizeof(struct udphdr)] = {}; + struct udphdr *udp; + + udp = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!udp) + return false; + + if (!(pckt->flags & F_ICMP)) { + pckt->port16[0] = udp->source; + pckt->port16[1] = udp->dest; + } else { + pckt->port16[0] = udp->dest; + pckt->port16[1] = udp->source; + } + return true; +} + +static __noinline bool parse_tcp(struct bpf_dynptr *skb_ptr, __u64 off, + struct packet_description *pckt) +{ + __u8 buffer[sizeof(struct tcphdr)] = {}; + struct tcphdr *tcp; + + tcp = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!tcp) + return false; + + if (tcp->syn) + pckt->flags |= F_SYN_SET; + + if (!(pckt->flags & F_ICMP)) { + pckt->port16[0] = tcp->source; + pckt->port16[1] = tcp->dest; + } else { + pckt->port16[0] = tcp->dest; + pckt->port16[1] = tcp->source; + } + return true; +} + +static __noinline int process_packet(struct bpf_dynptr *skb_ptr, + struct eth_hdr *eth, __u64 off, + bool is_ipv6, struct __sk_buff *skb) +{ + struct packet_description pckt = {}; + struct bpf_tunnel_key tkey = {}; + struct vip_stats *data_stats; + struct real_definition *dst; + struct vip_meta *vip_info; + struct ctl_value *cval; + __u32 v4_intf_pos = 1; + __u32 v6_intf_pos = 2; + struct ipv6hdr *ip6h; + struct vip vip = {}; + struct iphdr *iph; + int tun_flag = 0; + __u16 pkt_bytes; + __u64 iph_len; + __u32 ifindex; + __u8 protocol; + __u32 vip_num; + int action; + + tkey.tunnel_ttl = 64; + if (is_ipv6) { + __u8 buffer[sizeof(struct ipv6hdr)] = {}; + + ip6h = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!ip6h) + return TC_ACT_SHOT; + + iph_len = sizeof(struct ipv6hdr); + protocol = ip6h->nexthdr; + pckt.proto = protocol; + pkt_bytes = bpf_ntohs(ip6h->payload_len); + off += iph_len; + if (protocol == IPPROTO_FRAGMENT) { + return TC_ACT_SHOT; + } else if (protocol == IPPROTO_ICMPV6) { + action = parse_icmpv6(skb_ptr, off, &pckt); + if (action >= 0) + return action; + off += IPV6_PLUS_ICMP_HDR; + } else { + memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16); + memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16); + } + } else { + __u8 buffer[sizeof(struct iphdr)] = {}; + + iph = bpf_dynptr_slice(skb_ptr, off, buffer, sizeof(buffer)); + if (!iph || iph->ihl != 5) + return TC_ACT_SHOT; + + protocol = iph->protocol; + pckt.proto = protocol; + pkt_bytes = bpf_ntohs(iph->tot_len); + off += IPV4_HDR_LEN_NO_OPT; + + if (iph->frag_off & PCKT_FRAGMENTED) + return TC_ACT_SHOT; + if (protocol == IPPROTO_ICMP) { + action = parse_icmp(skb_ptr, off, &pckt); + if (action >= 0) + return action; + off += IPV4_PLUS_ICMP_HDR; + } else { + pckt.src = iph->saddr; + pckt.dst = iph->daddr; + } + } + protocol = pckt.proto; + + if (protocol == IPPROTO_TCP) { + if (!parse_tcp(skb_ptr, off, &pckt)) + return TC_ACT_SHOT; + } else if (protocol == IPPROTO_UDP) { + if (!parse_udp(skb_ptr, off, &pckt)) + return TC_ACT_SHOT; + } else { + return TC_ACT_SHOT; + } + + if (is_ipv6) + memcpy(vip.daddr.v6, pckt.dstv6, 16); + else + vip.daddr.v4 = pckt.dst; + + vip.dport = pckt.port16[1]; + vip.protocol = pckt.proto; + vip_info = bpf_map_lookup_elem(&vip_map, &vip); + if (!vip_info) { + vip.dport = 0; + vip_info = bpf_map_lookup_elem(&vip_map, &vip); + if (!vip_info) + return TC_ACT_SHOT; + pckt.port16[1] = 0; + } + + if (vip_info->flags & F_HASH_NO_SRC_PORT) + pckt.port16[0] = 0; + + if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6)) + return TC_ACT_SHOT; + + if (dst->flags & F_IPV6) { + cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos); + if (!cval) + return TC_ACT_SHOT; + ifindex = cval->ifindex; + memcpy(tkey.remote_ipv6, dst->dstv6, 16); + tun_flag = BPF_F_TUNINFO_IPV6; + } else { + cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos); + if (!cval) + return TC_ACT_SHOT; + ifindex = cval->ifindex; + tkey.remote_ipv4 = dst->dst; + } + vip_num = vip_info->vip_num; + data_stats = bpf_map_lookup_elem(&stats, &vip_num); + if (!data_stats) + return TC_ACT_SHOT; + data_stats->pkts++; + data_stats->bytes += pkt_bytes; + bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag); + *(u32 *)eth->eth_dest = tkey.remote_ipv4; + return bpf_redirect(ifindex, 0); +} + +SEC("tc") +int balancer_ingress(struct __sk_buff *ctx) +{ + __u8 buffer[sizeof(struct eth_hdr)] = {}; + struct bpf_dynptr ptr; + struct eth_hdr *eth; + __u32 eth_proto; + __u32 nh_off; + int err; + + nh_off = sizeof(struct eth_hdr); + + bpf_dynptr_from_skb(ctx, 0, &ptr); + eth = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer)); + if (!eth) + return TC_ACT_SHOT; + eth_proto = eth->eth_proto; + if (eth_proto == bpf_htons(ETH_P_IP)) + err = process_packet(&ptr, eth, nh_off, false, ctx); + else if (eth_proto == bpf_htons(ETH_P_IPV6)) + err = process_packet(&ptr, eth, nh_off, true, ctx); + else + return TC_ACT_SHOT; + + if (eth == buffer) + bpf_dynptr_write(&ptr, 0, buffer, sizeof(buffer), 0); + + return err; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c new file mode 100644 index 000000000000..79bab9b50e9e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c @@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* This parsing logic is taken from the open source library katran, a layer 4 + * load balancer. + * + * This code logic using dynptrs can be found in test_parse_tcp_hdr_opt_dynptr.c + * + * https://github.com/facebookincubator/katran/blob/main/katran/lib/bpf/pckt_parsing.h + */ + +#include +#include +#include +#include +#include +#include +#include "test_tcp_hdr_options.h" + +char _license[] SEC("license") = "GPL"; + +/* Kind number used for experiments */ +const __u32 tcp_hdr_opt_kind_tpr = 0xFD; +/* Length of the tcp header option */ +const __u32 tcp_hdr_opt_len_tpr = 6; +/* maximum number of header options to check to lookup server_id */ +const __u32 tcp_hdr_opt_max_opt_checks = 15; + +__u32 server_id; + +struct hdr_opt_state { + __u32 server_id; + __u8 byte_offset; + __u8 hdr_bytes_remaining; +}; + +static int parse_hdr_opt(const struct xdp_md *xdp, struct hdr_opt_state *state) +{ + const void *data = (void *)(long)xdp->data; + const void *data_end = (void *)(long)xdp->data_end; + __u8 *tcp_opt, kind, hdr_len; + + tcp_opt = (__u8 *)(data + state->byte_offset); + if (tcp_opt + 1 > data_end) + return -1; + + kind = tcp_opt[0]; + + if (kind == TCPOPT_EOL) + return -1; + + if (kind == TCPOPT_NOP) { + state->hdr_bytes_remaining--; + state->byte_offset++; + return 0; + } + + if (state->hdr_bytes_remaining < 2 || + tcp_opt + sizeof(__u8) + sizeof(__u8) > data_end) + return -1; + + hdr_len = tcp_opt[1]; + if (hdr_len > state->hdr_bytes_remaining) + return -1; + + if (kind == tcp_hdr_opt_kind_tpr) { + if (hdr_len != tcp_hdr_opt_len_tpr) + return -1; + + if (tcp_opt + tcp_hdr_opt_len_tpr > data_end) + return -1; + + state->server_id = *(__u32 *)&tcp_opt[2]; + return 1; + } + + state->hdr_bytes_remaining -= hdr_len; + state->byte_offset += hdr_len; + return 0; +} + +SEC("xdp") +int xdp_ingress_v6(struct xdp_md *xdp) +{ + const void *data = (void *)(long)xdp->data; + const void *data_end = (void *)(long)xdp->data_end; + struct hdr_opt_state opt_state = {}; + __u8 tcp_hdr_opt_len = 0; + struct tcphdr *tcp_hdr; + __u64 tcp_offset = 0; + __u32 off; + int err; + + tcp_offset = sizeof(struct ethhdr) + sizeof(struct ipv6hdr); + tcp_hdr = (struct tcphdr *)(data + tcp_offset); + if (tcp_hdr + 1 > data_end) + return XDP_DROP; + + tcp_hdr_opt_len = (tcp_hdr->doff * 4) - sizeof(struct tcphdr); + if (tcp_hdr_opt_len < tcp_hdr_opt_len_tpr) + return XDP_DROP; + + opt_state.hdr_bytes_remaining = tcp_hdr_opt_len; + opt_state.byte_offset = sizeof(struct tcphdr) + tcp_offset; + + /* max number of bytes of options in tcp header is 40 bytes */ + for (int i = 0; i < tcp_hdr_opt_max_opt_checks; i++) { + err = parse_hdr_opt(xdp, &opt_state); + + if (err || !opt_state.hdr_bytes_remaining) + break; + } + + if (!opt_state.server_id) + return XDP_DROP; + + server_id = opt_state.server_id; + + return XDP_PASS; +} diff --git a/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c new file mode 100644 index 000000000000..d3b319722e30 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* This logic is lifted from a real-world use case of packet parsing, used in + * the open source library katran, a layer 4 load balancer. + * + * This test demonstrates how to parse packet contents using dynptrs. The + * original code (parsing without dynptrs) can be found in test_parse_tcp_hdr_opt.c + */ + +#include +#include +#include +#include +#include +#include +#include "test_tcp_hdr_options.h" +#include "bpf_kfuncs.h" + +char _license[] SEC("license") = "GPL"; + +/* Kind number used for experiments */ +const __u32 tcp_hdr_opt_kind_tpr = 0xFD; +/* Length of the tcp header option */ +const __u32 tcp_hdr_opt_len_tpr = 6; +/* maximum number of header options to check to lookup server_id */ +const __u32 tcp_hdr_opt_max_opt_checks = 15; + +__u32 server_id; + +static int parse_hdr_opt(struct bpf_dynptr *ptr, __u32 *off, __u8 *hdr_bytes_remaining, + __u32 *server_id) +{ + __u8 *tcp_opt, kind, hdr_len; + __u8 buffer[sizeof(kind) + sizeof(hdr_len) + sizeof(*server_id)]; + __u8 *data; + + __builtin_memset(buffer, 0, sizeof(buffer)); + + data = bpf_dynptr_slice(ptr, *off, buffer, sizeof(buffer)); + if (!data) + return -1; + + kind = data[0]; + + if (kind == TCPOPT_EOL) + return -1; + + if (kind == TCPOPT_NOP) { + *off += 1; + *hdr_bytes_remaining -= 1; + return 0; + } + + if (*hdr_bytes_remaining < 2) + return -1; + + hdr_len = data[1]; + if (hdr_len > *hdr_bytes_remaining) + return -1; + + if (kind == tcp_hdr_opt_kind_tpr) { + if (hdr_len != tcp_hdr_opt_len_tpr) + return -1; + + __builtin_memcpy(server_id, (__u32 *)(data + 2), sizeof(*server_id)); + return 1; + } + + *off += hdr_len; + *hdr_bytes_remaining -= hdr_len; + return 0; +} + +SEC("xdp") +int xdp_ingress_v6(struct xdp_md *xdp) +{ + __u8 buffer[sizeof(struct tcphdr)] = {}; + __u8 hdr_bytes_remaining; + struct tcphdr *tcp_hdr; + __u8 tcp_hdr_opt_len; + int err = 0; + __u32 off; + + struct bpf_dynptr ptr; + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + + off = sizeof(struct ethhdr) + sizeof(struct ipv6hdr); + + tcp_hdr = bpf_dynptr_slice(&ptr, off, buffer, sizeof(buffer)); + if (!tcp_hdr) + return XDP_DROP; + + tcp_hdr_opt_len = (tcp_hdr->doff * 4) - sizeof(struct tcphdr); + if (tcp_hdr_opt_len < tcp_hdr_opt_len_tpr) + return XDP_DROP; + + hdr_bytes_remaining = tcp_hdr_opt_len; + + off += sizeof(struct tcphdr); + + /* max number of bytes of options in tcp header is 40 bytes */ + for (int i = 0; i < tcp_hdr_opt_max_opt_checks; i++) { + err = parse_hdr_opt(&ptr, &off, &hdr_bytes_remaining, &server_id); + + if (err || !hdr_bytes_remaining) + break; + } + + if (!server_id) + return XDP_DROP; + + return XDP_PASS; +} diff --git a/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c new file mode 100644 index 000000000000..7521a805b506 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "test_iptunnel_common.h" +#include "bpf_kfuncs.h" + +const size_t tcphdr_sz = sizeof(struct tcphdr); +const size_t udphdr_sz = sizeof(struct udphdr); +const size_t ethhdr_sz = sizeof(struct ethhdr); +const size_t iphdr_sz = sizeof(struct iphdr); +const size_t ipv6hdr_sz = sizeof(struct ipv6hdr); + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 256); + __type(key, __u32); + __type(value, __u64); +} rxcnt SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, MAX_IPTNL_ENTRIES); + __type(key, struct vip); + __type(value, struct iptnl_info); +} vip2tnl SEC(".maps"); + +static __always_inline void count_tx(__u32 protocol) +{ + __u64 *rxcnt_count; + + rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol); + if (rxcnt_count) + *rxcnt_count += 1; +} + +static __always_inline int get_dport(void *trans_data, __u8 protocol) +{ + struct tcphdr *th; + struct udphdr *uh; + + switch (protocol) { + case IPPROTO_TCP: + th = (struct tcphdr *)trans_data; + return th->dest; + case IPPROTO_UDP: + uh = (struct udphdr *)trans_data; + return uh->dest; + default: + return 0; + } +} + +static __always_inline void set_ethhdr(struct ethhdr *new_eth, + const struct ethhdr *old_eth, + const struct iptnl_info *tnl, + __be16 h_proto) +{ + memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source)); + memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest)); + new_eth->h_proto = h_proto; +} + +static __always_inline int handle_ipv4(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr) +{ + __u8 eth_buffer[ethhdr_sz + iphdr_sz + ethhdr_sz]; + __u8 iph_buffer_tcp[iphdr_sz + tcphdr_sz]; + __u8 iph_buffer_udp[iphdr_sz + udphdr_sz]; + struct bpf_dynptr new_xdp_ptr; + struct iptnl_info *tnl; + struct ethhdr *new_eth; + struct ethhdr *old_eth; + __u32 transport_hdr_sz; + struct iphdr *iph; + __u16 *next_iph; + __u16 payload_len; + struct vip vip = {}; + int dport; + __u32 csum = 0; + int i; + + __builtin_memset(eth_buffer, 0, sizeof(eth_buffer)); + __builtin_memset(iph_buffer_tcp, 0, sizeof(iph_buffer_tcp)); + __builtin_memset(iph_buffer_udp, 0, sizeof(iph_buffer_udp)); + + if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data) + iph = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, iph_buffer_udp, sizeof(iph_buffer_udp)); + else + iph = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, iph_buffer_tcp, sizeof(iph_buffer_tcp)); + + if (!iph) + return XDP_DROP; + + dport = get_dport(iph + 1, iph->protocol); + if (dport == -1) + return XDP_DROP; + + vip.protocol = iph->protocol; + vip.family = AF_INET; + vip.daddr.v4 = iph->daddr; + vip.dport = dport; + payload_len = bpf_ntohs(iph->tot_len); + + tnl = bpf_map_lookup_elem(&vip2tnl, &vip); + /* It only does v4-in-v4 */ + if (!tnl || tnl->family != AF_INET) + return XDP_PASS; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)iphdr_sz)) + return XDP_DROP; + + bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr); + new_eth = bpf_dynptr_slice_rdwr(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer)); + if (!new_eth) + return XDP_DROP; + + iph = (struct iphdr *)(new_eth + 1); + old_eth = (struct ethhdr *)(iph + 1); + + set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP)); + + if (new_eth == eth_buffer) + bpf_dynptr_write(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer), 0); + + iph->version = 4; + iph->ihl = iphdr_sz >> 2; + iph->frag_off = 0; + iph->protocol = IPPROTO_IPIP; + iph->check = 0; + iph->tos = 0; + iph->tot_len = bpf_htons(payload_len + iphdr_sz); + iph->daddr = tnl->daddr.v4; + iph->saddr = tnl->saddr.v4; + iph->ttl = 8; + + next_iph = (__u16 *)iph; + for (i = 0; i < iphdr_sz >> 1; i++) + csum += *next_iph++; + + iph->check = ~((csum & 0xffff) + (csum >> 16)); + + count_tx(vip.protocol); + + return XDP_TX; +} + +static __always_inline int handle_ipv6(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr) +{ + __u8 eth_buffer[ethhdr_sz + ipv6hdr_sz + ethhdr_sz]; + __u8 ip6h_buffer_tcp[ipv6hdr_sz + tcphdr_sz]; + __u8 ip6h_buffer_udp[ipv6hdr_sz + udphdr_sz]; + struct bpf_dynptr new_xdp_ptr; + struct iptnl_info *tnl; + struct ethhdr *new_eth; + struct ethhdr *old_eth; + __u32 transport_hdr_sz; + struct ipv6hdr *ip6h; + __u16 payload_len; + struct vip vip = {}; + int dport; + + __builtin_memset(eth_buffer, 0, sizeof(eth_buffer)); + __builtin_memset(ip6h_buffer_tcp, 0, sizeof(ip6h_buffer_tcp)); + __builtin_memset(ip6h_buffer_udp, 0, sizeof(ip6h_buffer_udp)); + + if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data) + ip6h = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, ip6h_buffer_udp, sizeof(ip6h_buffer_udp)); + else + ip6h = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, ip6h_buffer_tcp, sizeof(ip6h_buffer_tcp)); + + if (!ip6h) + return XDP_DROP; + + dport = get_dport(ip6h + 1, ip6h->nexthdr); + if (dport == -1) + return XDP_DROP; + + vip.protocol = ip6h->nexthdr; + vip.family = AF_INET6; + memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr)); + vip.dport = dport; + payload_len = ip6h->payload_len; + + tnl = bpf_map_lookup_elem(&vip2tnl, &vip); + /* It only does v6-in-v6 */ + if (!tnl || tnl->family != AF_INET6) + return XDP_PASS; + + if (bpf_xdp_adjust_head(xdp, 0 - (int)ipv6hdr_sz)) + return XDP_DROP; + + bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr); + new_eth = bpf_dynptr_slice_rdwr(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer)); + if (!new_eth) + return XDP_DROP; + + ip6h = (struct ipv6hdr *)(new_eth + 1); + old_eth = (struct ethhdr *)(ip6h + 1); + + set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6)); + + if (new_eth == eth_buffer) + bpf_dynptr_write(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer), 0); + + ip6h->version = 6; + ip6h->priority = 0; + memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl)); + ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + ipv6hdr_sz); + ip6h->nexthdr = IPPROTO_IPV6; + ip6h->hop_limit = 8; + memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6)); + memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6)); + + count_tx(vip.protocol); + + return XDP_TX; +} + +SEC("xdp") +int _xdp_tx_iptunnel(struct xdp_md *xdp) +{ + __u8 buffer[ethhdr_sz]; + struct bpf_dynptr ptr; + struct ethhdr *eth; + __u16 h_proto; + + __builtin_memset(buffer, 0, sizeof(buffer)); + + bpf_dynptr_from_xdp(xdp, 0, &ptr); + eth = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer)); + if (!eth) + return XDP_DROP; + + h_proto = eth->h_proto; + + if (h_proto == bpf_htons(ETH_P_IP)) + return handle_ipv4(xdp, &ptr); + else if (h_proto == bpf_htons(ETH_P_IPV6)) + + return handle_ipv6(xdp, &ptr); + else + return XDP_DROP; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_tcp_hdr_options.h b/tools/testing/selftests/bpf/test_tcp_hdr_options.h index 6118e3ab61fc..56c9f8a3ad3d 100644 --- a/tools/testing/selftests/bpf/test_tcp_hdr_options.h +++ b/tools/testing/selftests/bpf/test_tcp_hdr_options.h @@ -50,6 +50,7 @@ struct linum_err { #define TCPOPT_EOL 0 #define TCPOPT_NOP 1 +#define TCPOPT_MSS 2 #define TCPOPT_WINDOW 3 #define TCPOPT_EXP 254