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AJvYcCV/wwFQIWYgrLUcAFmzb9vEUYCrkwX7p40ZdDHxSZm0Rtlkgqd9fuYgmnirTFGyTeJdYa6LkSkLuIi7aEs9uzsIuKmzyTnSbGH5rQZ+A6gP X-Gm-Message-State: AOJu0YxY8uSWZwLCe7z9dSd69e4ksMfgfwCW1aoOACWCKObCTxuzmyLv qUcJaKsQrKDYdBSYD9hG8BEQw6BqR8OfzrIEPszAMDsVNiFaMbJyHK2nW55383M= X-Google-Smtp-Source: AGHT+IHp6WfuUeDSjQx2cauv1mQ/eMbX3s4chl5kJVOY3tZJvKu5JYf89lzfYO6yWTa1+IHjqNIpUg== X-Received: by 2002:a05:6a21:7890:b0:1a1:6cf5:5bf1 with SMTP id bf16-20020a056a21789000b001a16cf55bf1mr3944233pzc.12.1710149676017; Mon, 11 Mar 2024 02:34:36 -0700 (PDT) Received: from localhost.localdomain ([43.129.25.208]) by smtp.gmail.com with ESMTPSA id h9-20020a170902f7c900b001dcad9cbf8bsm4253365plw.239.2024.03.11.02.34.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Mar 2024 02:34:35 -0700 (PDT) From: Menglong Dong To: andrii@kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, davem@davemloft.net, dsahern@kernel.org, dave.hansen@linux.intel.com, x86@kernel.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, quentin@isovalent.com, bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, Menglong Dong Subject: [PATCH bpf-next v2 1/9] bpf: tracing: add support to record and check the accessed args Date: Mon, 11 Mar 2024 17:35:18 +0800 Message-Id: <20240311093526.1010158-2-dongmenglong.8@bytedance.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240311093526.1010158-1-dongmenglong.8@bytedance.com> References: <20240311093526.1010158-1-dongmenglong.8@bytedance.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In this commit, we add the 'accessed_args' field to struct bpf_prog_aux, which is used to record the accessed index of the function args in btf_ctx_access(). Meanwhile, we add the function btf_check_func_part_match() to compare the accessed function args of two function prototype. This function will be used in the following commit. Signed-off-by: Menglong Dong --- include/linux/bpf.h | 4 ++ kernel/bpf/btf.c | 108 +++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 110 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 95e07673cdc1..0f677fdcfcc7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1461,6 +1461,7 @@ struct bpf_prog_aux { const struct btf_type *attach_func_proto; /* function name for valid attach_btf_id */ const char *attach_func_name; + u64 accessed_args; struct bpf_prog **func; void *jit_data; /* JIT specific data. arch dependent */ struct bpf_jit_poke_descriptor *poke_tab; @@ -2565,6 +2566,9 @@ struct bpf_reg_state; int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog); int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog, struct btf *btf, const struct btf_type *t); +int btf_check_func_part_match(struct btf *btf1, const struct btf_type *t1, + struct btf *btf2, const struct btf_type *t2, + u64 func_args); const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt, int comp_idx, const char *tag_key); int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt, diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 170d017e8e4a..c2a0299d4358 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6125,19 +6125,24 @@ static bool is_int_ptr(struct btf *btf, const struct btf_type *t) } static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto, - int off) + int off, int *aligned_idx) { const struct btf_param *args; const struct btf_type *t; u32 offset = 0, nr_args; int i; + if (aligned_idx) + *aligned_idx = -ENOENT; + if (!func_proto) return off / 8; nr_args = btf_type_vlen(func_proto); args = (const struct btf_param *)(func_proto + 1); for (i = 0; i < nr_args; i++) { + if (aligned_idx && offset == off) + *aligned_idx = i; t = btf_type_skip_modifiers(btf, args[i].type, NULL); offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8); if (off < offset) @@ -6207,7 +6212,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, tname, off); return false; } - arg = get_ctx_arg_idx(btf, t, off); + arg = get_ctx_arg_idx(btf, t, off, NULL); args = (const struct btf_param *)(t + 1); /* if (t == NULL) Fall back to default BPF prog with * MAX_BPF_FUNC_REG_ARGS u64 arguments. @@ -6217,6 +6222,9 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, /* skip first 'void *__data' argument in btf_trace_##name typedef */ args++; nr_args--; + prog->aux->accessed_args |= (1 << (arg + 1)); + } else { + prog->aux->accessed_args |= (1 << arg); } if (arg > nr_args) { @@ -7024,6 +7032,102 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr return btf_check_func_type_match(log, btf1, t1, btf2, t2); } +static u32 get_ctx_arg_total_size(struct btf *btf, const struct btf_type *t) +{ + const struct btf_param *args; + u32 size = 0, nr_args; + int i; + + nr_args = btf_type_vlen(t); + args = (const struct btf_param *)(t + 1); + for (i = 0; i < nr_args; i++) { + t = btf_type_skip_modifiers(btf, args[i].type, NULL); + size += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8); + } + + return size; +} + +/* This function is similar to btf_check_func_type_match(), except that it + * only compare some function args of the function prototype t1 and t2. + */ +int btf_check_func_part_match(struct btf *btf1, const struct btf_type *func1, + struct btf *btf2, const struct btf_type *func2, + u64 func_args) +{ + const struct btf_param *args1, *args2; + u32 nargs1, i, offset = 0; + const char *s1, *s2; + + if (!btf_type_is_func_proto(func1) || !btf_type_is_func_proto(func2)) + return -EINVAL; + + args1 = (const struct btf_param *)(func1 + 1); + args2 = (const struct btf_param *)(func2 + 1); + nargs1 = btf_type_vlen(func1); + + for (i = 0; i <= nargs1; i++) { + const struct btf_type *t1, *t2; + + if (!(func_args & (1 << i))) + goto next; + + if (i < nargs1) { + int t2_index; + + /* get the index of the arg corresponding to args1[i] + * by the offset. + */ + get_ctx_arg_idx(btf2, func2, offset, &t2_index); + if (t2_index < 0) + return -EINVAL; + + t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL); + t2 = btf_type_skip_modifiers(btf2, args2[t2_index].type, + NULL); + } else { + /* i == nargs1, this is the index of return value of t1 */ + if (get_ctx_arg_total_size(btf1, func1) != + get_ctx_arg_total_size(btf2, func2)) + return -EINVAL; + + /* check the return type of t1 and t2 */ + t1 = btf_type_skip_modifiers(btf1, func1->type, NULL); + t2 = btf_type_skip_modifiers(btf2, func2->type, NULL); + } + + if (t1->info != t2->info || + (btf_type_has_size(t1) && t1->size != t2->size)) + return -EINVAL; + if (btf_type_is_int(t1) || btf_is_any_enum(t1)) + goto next; + + if (btf_type_is_struct(t1)) + goto on_struct; + + if (!btf_type_is_ptr(t1)) + return -EINVAL; + + t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); + t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); + if (!btf_type_is_struct(t1) || !btf_type_is_struct(t2)) + return -EINVAL; + +on_struct: + s1 = btf_name_by_offset(btf1, t1->name_off); + s2 = btf_name_by_offset(btf2, t2->name_off); + if (strcmp(s1, s2)) + return -EINVAL; +next: + if (i < nargs1) { + t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL); + offset += btf_type_is_ptr(t1) ? 8 : roundup(t1->size, 8); + } + } + + return 0; +} + static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t) { const char *name;