From patchwork Thu Nov 3 19:10:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kumar Kartikeya Dwivedi X-Patchwork-Id: 13030880 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 09721C4332F for ; Thu, 3 Nov 2022 19:11:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231355AbiKCTLR (ORCPT ); Thu, 3 Nov 2022 15:11:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231339AbiKCTLQ (ORCPT ); Thu, 3 Nov 2022 15:11:16 -0400 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9E391D674 for ; Thu, 3 Nov 2022 12:11:15 -0700 (PDT) Received: by mail-pg1-x543.google.com with SMTP id 78so2472541pgb.13 for ; Thu, 03 Nov 2022 12:11:15 -0700 (PDT) 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=m2j5SVxRaqjpNKkttqB+k1TA+7fy+fEVI29qI5hXzm4=; b=CULOkYcNGIgqZbtNDm3Q+iZuWUd2pLmEEKklE7GxUDAqNFueWw6H9Cg38FqVBJzPk6 xyYpy2gnur0nJTduSTcXfOpeQZ0NRmxebDxltDPonBREkt7TSR3yS7gxwLXcnSGwTjuu 3w6xoYH0a/1TlWuzqovFinnq6Q9/DEEn581v4xAN2KlJSKvgI94ceZSuAK8tu2Gc96SB wvEqQfCXcPsNxFOf4VpQG2VG6EnftdprA3zLHDFpu1HzbxEXAaSFxzKpxfVe/jmRoxBi srswj891mck5xGTJxyHTBGbCUusxydA0CCOQ6oMHXDFgiB8/y1PyRdlbXwos9v6RBGrz sXDA== 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=m2j5SVxRaqjpNKkttqB+k1TA+7fy+fEVI29qI5hXzm4=; b=7ykKjulDg8dSVcqks2uFMMp3SsAA2jGtbJeUnRz69JKpu2j/0k5cq8UfZt7FBKq6Sp l3FbKQaywSmAMB8IAZjTzyUV5I0dC77B/hliNhG2vUb9j/hNfXzEAgcXHRQsa2yHSea7 opi5l0Lh3LIx3x/lNZNeoI2QMRopIKz+Jl693UBa9xN7gzaYTtpi5fJQiBm9foFY1M87 1Q7eoRRoSu2XYpmZE85T64CASL3CcDcFYA9iD+GiCWxy/xZtFnDFRp0WqibACMi3kqmo d3AGj9+jXvlxMHJYnz4U7kY8yYE8PpOomCxfsqTGRiDlhd/60jjihw7xgpKhupMuuOPZ xy7w== X-Gm-Message-State: ACrzQf0AKZx/5iwDP4SUlWNyjwegMo50YaAnSai1GMoFYADVqDkHsyGo tt0FRvWzSWlMAcCRm6OYDRxC3SzEk7yePg== X-Google-Smtp-Source: AMsMyM70xjEs4R3yjzdc6nLrklbXQGaVl4G3NqFZDgRaFlZ+5dOv3Fx03YnD2J3IhB8tw9y/lE3AIA== X-Received: by 2002:a05:6a00:88f:b0:558:8186:3ec3 with SMTP id q15-20020a056a00088f00b0055881863ec3mr31258273pfj.83.1667502674989; Thu, 03 Nov 2022 12:11:14 -0700 (PDT) Received: from localhost ([103.4.222.252]) by smtp.gmail.com with ESMTPSA id ix20-20020a170902f81400b00181f8523f60sm973382plb.225.2022.11.03.12.11.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Nov 2022 12:11:14 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Dave Marchevsky , Delyan Kratunov Subject: [PATCH bpf-next v4 13/24] bpf: Support locking bpf_spin_lock in local kptr Date: Fri, 4 Nov 2022 00:40:02 +0530 Message-Id: <20221103191013.1236066-14-memxor@gmail.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221103191013.1236066-1-memxor@gmail.com> References: <20221103191013.1236066-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6465; i=memxor@gmail.com; h=from:subject; bh=lKKP2nMUqCOuDchEBIlYCb6PpFP48R7dteaXbTIU/t4=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBjZBIByDA5xgaUSJ80ZK541TqBzs9C8Z9diRJZgygN sXHgte+JAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCY2QSAQAKCRBM4MiGSL8RynYrEA DDlHyMjMdcLc/01CTV5vYphACEsgU4wTCouk1b/QHov4SzjBulGsuDXPaUA07MoPxZBXIiI9/j/1hC sYRRHjHWtR+VHuFDfLKtOdzzzjThCKVRkPO9JJbQSLWjKvQwlRrmn2/fJ/0hAHRRmp38vpSd3O5nfY YfcIAqF1Hool5qHG1AmOJzhgjlbvKsxUCurn9wKQlnh/phKine0tt2pIj7m2pDnHZRQ7EZ49K/e9cA +rOja2IrPWXFI8Diha59k31sYz45DOVIJZbNI9k3Hy+6uQnHmkUht/eihMwFRMYhZ4jYGf3Jszg8RT M4ui6TEHkAcs6QfuCOfWra9R/IjL4Q5zHPOeEBUQ9slSjQc6R7uA4AFESlw8zceBGBh8bCQpvIqiGP 9yKJnjUTqfjMSts6kXjvpbrSlbOW+/JM6Ky3UuOzpKSQJwsNRpkzE6t42wwCW6Z9UJyip7Bon2ImWF 3KwOmpVyp5xLp90kQVI74zWwM82tGZJKnd0SxK1qqJOiWPfZ80uYDN/Maymp6Mtb0I7pD772qiIjiN IoNYXXUHq82dmPjlsL+zn8OMR95YgKsSTMpFZ0BHIqhVlLM+XCNP2W33lNoJrhq2B0pM9/b0nLAKb3 XCRO+m3N67vGGfExulfRHivq3P4LoAeCDr66uehSDi/eS+GeO127sqbQBTzQ== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Allow locking a bpf_spin_lock embedded in local kptr, in addition to already support map value pointers. The handling is similar to that of map values, by just preserving the reg->id of local kptrs as well, and adjusting process_spin_lock to work with non-PTR_TO_MAP_VALUE and remember the id in verifier state. Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/helpers.c | 2 ++ kernel/bpf/verifier.c | 70 ++++++++++++++++++++++++++++++++----------- 2 files changed, 55 insertions(+), 17 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 339cce94b408..207f622ec70d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -336,6 +336,7 @@ const struct bpf_func_proto bpf_spin_lock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock) @@ -358,6 +359,7 @@ const struct bpf_func_proto bpf_spin_unlock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; void copy_map_value_locked(struct bpf_map *map, void *dst, void *src, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4de72a4a39bb..c31f20aed30c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -453,8 +453,16 @@ static bool reg_type_not_null(enum bpf_reg_type type) static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) { - return reg->type == PTR_TO_MAP_VALUE && - btf_record_has_field(reg->map_ptr->record, BPF_SPIN_LOCK); + struct btf_record *rec = NULL; + + if (reg->type == PTR_TO_MAP_VALUE) { + rec = reg->map_ptr->record; + } else if (reg->type == (PTR_TO_BTF_ID | MEM_TYPE_LOCAL)) { + struct btf_struct_meta *meta = btf_find_struct_meta(reg->btf, reg->btf_id); + if (meta) + rec = meta->record; + } + return btf_record_has_field(rec, BPF_SPIN_LOCK); } static bool type_is_rdonly_mem(u32 type) @@ -5422,8 +5430,10 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; struct bpf_verifier_state *cur = env->cur_state; bool is_const = tnum_is_const(reg->var_off); - struct bpf_map *map = reg->map_ptr; u64 val = reg->var_off.value; + struct bpf_map *map = NULL; + struct btf_record *rec; + struct btf *btf = NULL; if (!is_const) { verbose(env, @@ -5431,19 +5441,32 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, regno); return -EINVAL; } - if (!map->btf) { - verbose(env, - "map '%s' has to have BTF in order to use bpf_spin_lock\n", - map->name); - return -EINVAL; + if (reg->type == PTR_TO_MAP_VALUE) { + map = reg->map_ptr; + if (!map->btf) { + verbose(env, + "map '%s' has to have BTF in order to use bpf_spin_lock\n", + map->name); + return -EINVAL; + } + rec = map->record; + } else { + struct btf_struct_meta *meta; + + btf = reg->btf; + meta = btf_find_struct_meta(reg->btf, reg->btf_id); + if (meta) + rec = meta->record; } - if (!btf_record_has_field(map->record, BPF_SPIN_LOCK)) { - verbose(env, "map '%s' has no valid bpf_spin_lock\n", map->name); + + if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) { + verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local", + map ? map->name : "kptr"); return -EINVAL; } - if (map->record->spin_lock_off != val + reg->off) { + if (rec->spin_lock_off != val + reg->off) { verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n", - val + reg->off, map->record->spin_lock_off); + val + reg->off, rec->spin_lock_off); return -EINVAL; } if (is_lock) { @@ -5649,13 +5672,19 @@ static const struct bpf_reg_types int_ptr_types = { }, }; +static const struct bpf_reg_types spin_lock_types = { + .types = { + PTR_TO_MAP_VALUE, + PTR_TO_BTF_ID | MEM_TYPE_LOCAL, + } +}; + static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } }; static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } }; static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; -static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } }; static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; @@ -5780,6 +5809,11 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, return -EACCES; } } + } else if (reg->type == (PTR_TO_BTF_ID | MEM_TYPE_LOCAL)) { + if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) { + verbose(env, "verifier internal error: unimplemented handling of local kptr\n"); + return -EFAULT; + } } return 0; @@ -5896,7 +5930,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto skip_type_check; /* arg_btf_id and arg_size are in a union. */ - if (base_type(arg_type) == ARG_PTR_TO_BTF_ID) + if (base_type(arg_type) == ARG_PTR_TO_BTF_ID || + base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK) arg_btf_id = fn->arg_btf_id[arg]; err = check_reg_type(env, regno, arg_type, arg_btf_id, meta); @@ -6514,9 +6549,10 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn) int i; for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) { - if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i]) - return false; - + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID) + return !!fn->arg_btf_id[i]; + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK) + return fn->arg_btf_id[i] == BPF_PTR_POISON; if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] && /* arg_btf_id and arg_size are in a union. */ (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||