From patchwork Tue Jun 21 01:28:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 12888630 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 EA389CCA47C for ; Tue, 21 Jun 2022 01:28:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240120AbiFUB2a (ORCPT ); Mon, 20 Jun 2022 21:28:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241578AbiFUB2V (ORCPT ); Mon, 20 Jun 2022 21:28:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B68601928B for ; Mon, 20 Jun 2022 18:28:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6A27BB811EC for ; Tue, 21 Jun 2022 01:28:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3106C341C5; Tue, 21 Jun 2022 01:28:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655774898; bh=LYcal6BP+mEOEdUdVWBC5q5Ju3rVmyi66+AjKEcUkCA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fLDtaXXJBFK8hXyMyE9N+/Kl5zvDvgEgl8CXVpH5N04aQZIRiIWrRSA31OlLOz/Fo NITzD/TNKs+UyBWbOGXQ7Q8NA+/HocRQGyyNsTgdXDsaz5pZKzCYPN/qom/09R5xW+ Thzoz/AAr34UHLP20c4ILq08FdM32GOTnd/fCnfj1wUyg6QxCLqmLxyDAqB/KsSdV2 GEVxpJOlclDlStOpi14pX01FjePNguhZSiRWMoDPfcmy/ZZsGdoh9/Gvhp10a3MXp3 fV4/mahPOpXDowxsjoelvMiCli2l+eBqYKQ1zbS8Dh3OAd7qGaiuXi0vMdosTmISWC JDD2kWTHWjjfg== From: KP Singh To: bpf@vger.kernel.org Cc: KP Singh , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Benjamin Tissoires , Yosry Ahmed Subject: [PATCH v2 bpf-next 1/5] btf: Add a new kfunc set which allows to mark a function to be sleepable Date: Tue, 21 Jun 2022 01:28:07 +0000 Message-Id: <20220621012811.2683313-2-kpsingh@kernel.org> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog In-Reply-To: <20220621012811.2683313-1-kpsingh@kernel.org> References: <20220621012811.2683313-1-kpsingh@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Benjamin Tissoires This allows to declare a kfunc as sleepable and prevents its use in a non sleepable program. Signed-off-by: Benjamin Tissoires Acked-by: KP Singh --- include/linux/btf.h | 2 ++ kernel/bpf/btf.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index 1bfed7fa0428..6e7517573d9e 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -18,6 +18,7 @@ enum btf_kfunc_type { BTF_KFUNC_TYPE_RELEASE, BTF_KFUNC_TYPE_RET_NULL, BTF_KFUNC_TYPE_KPTR_ACQUIRE, + BTF_KFUNC_TYPE_SLEEPABLE, BTF_KFUNC_TYPE_MAX, }; @@ -37,6 +38,7 @@ struct btf_kfunc_id_set { struct btf_id_set *release_set; struct btf_id_set *ret_null_set; struct btf_id_set *kptr_acquire_set; + struct btf_id_set *sleepable_set; }; struct btf_id_set *sets[BTF_KFUNC_TYPE_MAX]; }; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index f08037c31dd7..668ecf61649b 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6171,7 +6171,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, struct bpf_verifier_log *log = &env->log; u32 i, nargs, ref_id, ref_obj_id = 0; bool is_kfunc = btf_is_kernel(btf); - bool rel = false, kptr_get = false; + bool rel = false, kptr_get = false, sleepable = false; const char *func_name, *ref_tname; const struct btf_type *t, *ref_t; const struct btf_param *args; @@ -6202,9 +6202,10 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, } if (is_kfunc) { - /* Only kfunc can be release func */ rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog), BTF_KFUNC_TYPE_RELEASE, func_id); + sleepable = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog), + BTF_KFUNC_TYPE_SLEEPABLE, func_id); kptr_get = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog), BTF_KFUNC_TYPE_KPTR_ACQUIRE, func_id); } @@ -6404,6 +6405,13 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, func_name); return -EINVAL; } + + if (sleepable && !env->prog->aux->sleepable) { + bpf_log(log, "kernel function %s is sleepable but the program is not\n", + func_name); + return -EINVAL; + } + /* returns argument register number > 0 in case of reference release kfunc */ return rel ? ref_regno : 0; } From patchwork Tue Jun 21 01:28:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 12888632 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 624E3C433EF for ; Tue, 21 Jun 2022 01:28:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230330AbiFUB2a (ORCPT ); Mon, 20 Jun 2022 21:28:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242659AbiFUB2Y (ORCPT ); Mon, 20 Jun 2022 21:28:24 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F54B1928B for ; Mon, 20 Jun 2022 18:28:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 39311B811BD for ; Tue, 21 Jun 2022 01:28:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99578C341C8; Tue, 21 Jun 2022 01:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655774900; bh=uCzCkqxKsvpKuyqgDhv5DSnJm1cEprHnN5V0J61d9T4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=csP+pi3Q4b40HAHENpEeV+aM3EjuTDiMijHk1B0BWmlRjZwszOAu2uqFVS6K2V1/H VmCTtsu4tFROackwzcopM21c6yaxvNwcxJebQdFpbrvPBHJcrzkSKCUB38BXsNsD3/ C3oThZCkGVs37sA9RQjFIvPtbvbKa7NlAYmVFHnk1xWQKHtavxDp6rPsVxngE3R3d3 IUEyD2Ej8onPw9p+IEtxOuqPCNtaO/R0Y6Psd3AMLMZls0tckNthbLvo7aM0EXP4lt wcNaXzE7ee7dzlsXXCd8r3C1YMDqUl6x/rJI1HUPt37LEYFszc3/1Q1d2Eoz0B2CKk 7i1u/xQezux3g== From: KP Singh To: bpf@vger.kernel.org Cc: KP Singh , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Benjamin Tissoires , Yosry Ahmed Subject: [PATCH v2 bpf-next 2/5] bpf: kfunc support for ARG_PTR_TO_CONST_STR Date: Tue, 21 Jun 2022 01:28:08 +0000 Message-Id: <20220621012811.2683313-3-kpsingh@kernel.org> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog In-Reply-To: <20220621012811.2683313-1-kpsingh@kernel.org> References: <20220621012811.2683313-1-kpsingh@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net kfuncs can handle pointers to memory when the next argument is the size of the memory that can be read and verify these as ARG_CONST_SIZE_OR_ZERO Similarly add support for string constants (const char *) and verify it similar to ARG_PTR_TO_CONST_STR. Signed-off-by: KP Singh --- include/linux/bpf_verifier.h | 2 + kernel/bpf/btf.c | 29 ++++++++++++ kernel/bpf/verifier.c | 85 ++++++++++++++++++++---------------- 3 files changed, 79 insertions(+), 37 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 3930c963fa67..60d490354397 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -548,6 +548,8 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state u32 regno); int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno, u32 mem_size); +int check_const_str(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg, int regno); /* 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/btf.c b/kernel/bpf/btf.c index 668ecf61649b..02d7951591ae 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6162,6 +6162,26 @@ static bool is_kfunc_arg_mem_size(const struct btf *btf, return true; } +static bool btf_param_is_const_str_ptr(const struct btf *btf, + const struct btf_param *param) +{ + const struct btf_type *t; + + t = btf_type_by_id(btf, param->type); + if (!btf_type_is_ptr(t)) + return false; + + t = btf_type_by_id(btf, t->type); + if (!(BTF_INFO_KIND(t->info) == BTF_KIND_CONST)) + return false; + + t = btf_type_skip_modifiers(btf, t->type, NULL); + if (!strcmp(btf_name_by_offset(btf, t->name_off), "char")) + return true; + + return false; +} + static int btf_check_func_arg_match(struct bpf_verifier_env *env, const struct btf *btf, u32 func_id, struct bpf_reg_state *regs, @@ -6344,6 +6364,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, } else if (ptr_to_mem_ok) { const struct btf_type *resolve_ret; u32 type_size; + int err; if (is_kfunc) { bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]); @@ -6354,6 +6375,14 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, * When arg_mem_size is true, the pointer can be * void *. */ + if (btf_param_is_const_str_ptr(btf, &args[i])) { + err = check_const_str(env, reg, regno); + if (err < 0) + return err; + i++; + continue; + } + if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(log, btf, ref_t, 0) && (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2859901ffbe3..14a434792d7b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5840,6 +5840,52 @@ static u32 stack_slot_get_id(struct bpf_verifier_env *env, struct bpf_reg_state return state->stack[spi].spilled_ptr.id; } +int check_const_str(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg, int regno) +{ + struct bpf_map *map = reg->map_ptr; + int map_off; + u64 map_addr; + char *str_ptr; + int err; + + if (!bpf_map_is_rdonly(map)) { + verbose(env, "R%d does not point to a readonly map'\n", regno); + return -EACCES; + } + + if (!tnum_is_const(reg->var_off)) { + verbose(env, "R%d is not a constant address'\n", regno); + return -EACCES; + } + + if (!map->ops->map_direct_value_addr) { + verbose(env, + "no direct value access support for this map type\n"); + return -EACCES; + } + + err = check_map_access(env, regno, reg->off, map->value_size - reg->off, + false, ACCESS_HELPER); + if (err) + return err; + + map_off = reg->off + reg->var_off.value; + err = map->ops->map_direct_value_addr(map, &map_addr, map_off); + if (err) { + verbose(env, "direct value access on string failed\n"); + return err; + } + + str_ptr = (char *)(long)(map_addr); + if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) { + verbose(env, "string is not zero-terminated\n"); + return -EINVAL; + } + + return 0; +} + static int check_func_arg(struct bpf_verifier_env *env, u32 arg, struct bpf_call_arg_meta *meta, const struct bpf_func_proto *fn) @@ -6074,44 +6120,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, return err; err = check_ptr_alignment(env, reg, 0, size, true); } else if (arg_type == ARG_PTR_TO_CONST_STR) { - struct bpf_map *map = reg->map_ptr; - int map_off; - u64 map_addr; - char *str_ptr; - - if (!bpf_map_is_rdonly(map)) { - verbose(env, "R%d does not point to a readonly map'\n", regno); - return -EACCES; - } - - if (!tnum_is_const(reg->var_off)) { - verbose(env, "R%d is not a constant address'\n", regno); - return -EACCES; - } - - if (!map->ops->map_direct_value_addr) { - verbose(env, "no direct value access support for this map type\n"); - return -EACCES; - } - - err = check_map_access(env, regno, reg->off, - map->value_size - reg->off, false, - ACCESS_HELPER); - if (err) - return err; - - map_off = reg->off + reg->var_off.value; - err = map->ops->map_direct_value_addr(map, &map_addr, map_off); - if (err) { - verbose(env, "direct value access on string failed\n"); + err = check_const_str(env, reg, regno); + if (err < 0) return err; - } - - str_ptr = (char *)(long)(map_addr); - if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) { - verbose(env, "string is not zero-terminated\n"); - return -EINVAL; - } } else if (arg_type == ARG_PTR_TO_KPTR) { if (process_kptr_func(env, regno, meta)) return -EACCES; From patchwork Tue Jun 21 01:28:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 12888633 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 A116BC43334 for ; Tue, 21 Jun 2022 01:28:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240589AbiFUB2b (ORCPT ); Mon, 20 Jun 2022 21:28:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242778AbiFUB2Y (ORCPT ); Mon, 20 Jun 2022 21:28:24 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 629191929B for ; Mon, 20 Jun 2022 18:28:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 18703B811EC for ; Tue, 21 Jun 2022 01:28:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F971C341C4; Tue, 21 Jun 2022 01:28:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655774901; bh=CbobNexbSTRL4hb1DX7jZ8y8Bnbyzx+ASnJ+WrY38Ko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T11K8BnWYo8+1G92f9KAlcTd1u4z9tmrZNvh2ZtQjkijWG2fBVYEZEuLYtTKn82nX nxC6TJOc6FzzUxNPAQHC8rAbU+8T8tDFiX1SWDSfTUTfGF1f1sGWMBapZ6N7Uk5ocy 7V40y/wXGBxhRI9YJAHEUGqmSHNsdamIPP9+x/GX7MzQ7PuQ4LXdU8aSkqTGVXrq/r DKWdZBAk1debCOhSaasTRAtbo23cpVRt7mAsdqpbN5JalijYr8PVhacR7j0NMlsgIj iwCMfKwELIUpfdD2UkF6ZpX2J6mUHSvp2S56KG+N69CqxN8K1J9HyRZxsheFmya/ee lp/xqZCUEQpmg== From: KP Singh To: bpf@vger.kernel.org Cc: KP Singh , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Benjamin Tissoires , Yosry Ahmed Subject: [PATCH v2 bpf-next 3/5] bpf: Allow kfuncs to be used in LSM programs Date: Tue, 21 Jun 2022 01:28:09 +0000 Message-Id: <20220621012811.2683313-4-kpsingh@kernel.org> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog In-Reply-To: <20220621012811.2683313-1-kpsingh@kernel.org> References: <20220621012811.2683313-1-kpsingh@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net In preparation for the addition of bpf_getxattr kfunc. Signed-off-by: KP Singh --- kernel/bpf/btf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 02d7951591ae..541cf4635aa1 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -7264,6 +7264,7 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) case BPF_PROG_TYPE_STRUCT_OPS: return BTF_KFUNC_HOOK_STRUCT_OPS; case BPF_PROG_TYPE_TRACING: + case BPF_PROG_TYPE_LSM: return BTF_KFUNC_HOOK_TRACING; case BPF_PROG_TYPE_SYSCALL: return BTF_KFUNC_HOOK_SYSCALL; From patchwork Tue Jun 21 01:28:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 12888631 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 F3A7BCCA47E for ; Tue, 21 Jun 2022 01:28:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234350AbiFUB2a (ORCPT ); Mon, 20 Jun 2022 21:28:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242831AbiFUB2Z (ORCPT ); Mon, 20 Jun 2022 21:28:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A13681928B for ; Mon, 20 Jun 2022 18:28:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4A54061596 for ; Tue, 21 Jun 2022 01:28:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F170C341C5; Tue, 21 Jun 2022 01:28:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655774903; bh=7ru/BD8lvgDJnszDvUzzT9MCF7A89UGdXDKmbwMRzZ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xv/w32cd6RNANi9DSN6C5EJ7TEHeR2IsMdXkTyYfBaiPbRtc92bpph6MxHYqZH1HA 1XbFqxStdZHEhIUW18nNz1+7IArNM2HfUNBNegV3bqEx0Kg5UE8AWzvkCf05YEf98V gXUq4ByTEOucws5je9G4P4YmCKzDx1x/cOyLcweo3TtWctbS3SaFexK1DC3G4ZQmuX TEAiLy1qN/2YAWMw5PXTlD48AoNex59/4W5RDdVwMHUzXyeAW8vkJ2dtUwNSW1Z/Xx COTR4i9+EkQj31BSOvfNUolGaUls7kDFOtmlQ1cAQ75ZWa2KkFH+cYUQrFwip06i4S IQDVcylDaTgXg== From: KP Singh To: bpf@vger.kernel.org Cc: KP Singh , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Benjamin Tissoires , Yosry Ahmed Subject: [PATCH v2 bpf-next 4/5] bpf: Add a bpf_getxattr kfunc Date: Tue, 21 Jun 2022 01:28:10 +0000 Message-Id: <20220621012811.2683313-5-kpsingh@kernel.org> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog In-Reply-To: <20220621012811.2683313-1-kpsingh@kernel.org> References: <20220621012811.2683313-1-kpsingh@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net LSMs like SELinux store security state in xattrs. bpf_getxattr enables BPF LSM to implement similar functionality. In combination with bpf_local_storage, xattrs can be used to develop more complex security policies. This kfunc wraps around __vfs_getxattr which can sleep and is, therefore, limited to sleepable programs using the newly added sleepable_set for kfuncs. Signed-off-by: KP Singh Reported-by: kernel test robot Reported-by: kernel test robot --- kernel/trace/bpf_trace.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4be976cf7d63..b5682d55ebde 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -20,6 +20,7 @@ #include #include #include +#include #include @@ -1181,6 +1182,41 @@ static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = { .arg1_type = ARG_PTR_TO_CTX, }; +noinline __weak ssize_t bpf_getxattr(struct dentry *dentry, struct inode *inode, + const char *name, void *value, int size) +{ + return __vfs_getxattr(dentry, inode, name, value, size); +} + +BTF_SET_START(bpf_trace_kfunc_ids) +BTF_ID(func, bpf_getxattr) +BTF_SET_END(bpf_trace_kfunc_ids) + +BTF_SET_START(bpf_trace_sleepable_kfunc_ids) +BTF_ID(func, bpf_getxattr) +BTF_SET_END(bpf_trace_sleepable_kfunc_ids) + +static const struct btf_kfunc_id_set bpf_trace_kfunc_set = { + .owner = THIS_MODULE, + .check_set = &bpf_trace_kfunc_ids, + .sleepable_set = &bpf_trace_sleepable_kfunc_ids, +}; + +static int __init bpf_trace_kfunc_init(void) +{ + int ret; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, + &bpf_trace_kfunc_set); + if (!ret) + return ret; + + return register_btf_kfunc_id_set(BPF_PROG_TYPE_LSM, + &bpf_trace_kfunc_set); + +} +late_initcall(bpf_trace_kfunc_init); + static const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { From patchwork Tue Jun 21 01:28:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 12888634 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 B01D0CCA47C for ; Tue, 21 Jun 2022 01:28:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241056AbiFUB2b (ORCPT ); Mon, 20 Jun 2022 21:28:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46796 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243292AbiFUB21 (ORCPT ); Mon, 20 Jun 2022 21:28:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B0B91928B for ; Mon, 20 Jun 2022 18:28:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2149A61598 for ; Tue, 21 Jun 2022 01:28:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25A25C385A9; Tue, 21 Jun 2022 01:28:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655774905; bh=0LgVkL1ldA/mk8/nk4zJk2Opn3AP379tvwspSLDBYjI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fF+gqZ4zIE0zGSlt/V8+DmsH5nOZ2rXzm8Aai7gm/EinXB4PVxz4nIPM4DBA7zJXT qQJS927Q+qWxBbb3Fza23xT1cp0OS3Eek6jnDuHXvby91KCKtVcwzedMQ7OBnlhMkS iL2RrxFohyyTt7SpBqAehRnLsA+ijameJZAssGoSGnHy9e2DORhYkEGocU59A5TjYb IHcnmDX/4dH5/px+0eACP39yo/WuIhotFuweT7iq6R1SM8LC1I8QIzaljDqXeyXFec OY8XyD5VfjWEUKLeF776oE+IzcnlXh+rT+3ujiV8019vm/8YhQGPslWBp5wrhhxZgl 0SWZ1Ode0V5Ag== From: KP Singh To: bpf@vger.kernel.org Cc: KP Singh , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Benjamin Tissoires , Yosry Ahmed Subject: [PATCH v2 bpf-next 5/5] bpf/selftests: Add a selftest for bpf_getxattr Date: Tue, 21 Jun 2022 01:28:11 +0000 Message-Id: <20220621012811.2683313-6-kpsingh@kernel.org> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog In-Reply-To: <20220621012811.2683313-1-kpsingh@kernel.org> References: <20220621012811.2683313-1-kpsingh@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net A simple test that adds an xattr on a copied /bin/ls and reads it back when the copied ls is executed. Signed-off-by: KP Singh --- .../testing/selftests/bpf/prog_tests/xattr.c | 58 +++++++++++++++++++ tools/testing/selftests/bpf/progs/xattr.c | 37 ++++++++++++ 2 files changed, 95 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/xattr.c create mode 100644 tools/testing/selftests/bpf/progs/xattr.c diff --git a/tools/testing/selftests/bpf/prog_tests/xattr.c b/tools/testing/selftests/bpf/prog_tests/xattr.c new file mode 100644 index 000000000000..442b6c1aed0e --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/xattr.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2022 Google LLC. + */ + +#include +#include +#include "xattr.skel.h" + +#define XATTR_NAME "security.bpf" +#define XATTR_VALUE "test_progs" + +static unsigned int duration; + +void test_xattr(void) +{ + struct xattr *skel = NULL; + char tmp_dir_path[] = "/tmp/xattrXXXXXX"; + char tmp_exec_path[64]; + char cmd[256]; + int err; + + if (CHECK(!mkdtemp(tmp_dir_path), "mkdtemp", + "unable to create tmpdir: %d\n", errno)) + goto close_prog; + + snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_ls", + tmp_dir_path); + snprintf(cmd, sizeof(cmd), "cp /bin/ls %s", tmp_exec_path); + if (CHECK_FAIL(system(cmd))) + goto close_prog_rmdir; + + if (CHECK(setxattr(tmp_exec_path, XATTR_NAME, XATTR_VALUE, + sizeof(XATTR_VALUE), 0), + "setxattr", "unable to setxattr: %d", errno)) + goto close_prog_rmdir; + + skel = xattr__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto close_prog_rmdir; + + err = xattr__attach(skel); + if (!ASSERT_OK(err, "xattr__attach failed")) + goto close_prog_rmdir; + + snprintf(cmd, sizeof(cmd), "%s -l", tmp_exec_path); + if (CHECK_FAIL(system(cmd))) + goto close_prog_rmdir; + + ASSERT_EQ(skel->bss->result, 1, "xattr result"); + +close_prog_rmdir: + snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path); + system(cmd); +close_prog: + xattr__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/xattr.c b/tools/testing/selftests/bpf/progs/xattr.c new file mode 100644 index 000000000000..ccc078fb8ebd --- /dev/null +++ b/tools/testing/selftests/bpf/progs/xattr.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2022 Google LLC. + */ + +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +#define XATTR_NAME "security.bpf" +#define XATTR_VALUE "test_progs" + +__u64 result = 0; + +extern ssize_t bpf_getxattr(struct dentry *dentry, struct inode *inode, + const char *name, void *value, int size) __ksym; + +SEC("lsm.s/bprm_committed_creds") +void BPF_PROG(bprm_cc, struct linux_binprm *bprm) +{ + struct task_struct *current = bpf_get_current_task_btf(); + char dir_xattr_value[64] = {0}; + int xattr_sz = 0; + + xattr_sz = bpf_getxattr(bprm->file->f_path.dentry, + bprm->file->f_path.dentry->d_inode, XATTR_NAME, + dir_xattr_value, 64); + + if (xattr_sz <= 0) + return; + + if (!bpf_strncmp(dir_xattr_value, sizeof(XATTR_VALUE), XATTR_VALUE)) + result = 1; +}