From 3820729160440158a014add69cc0d371061a96b2 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 24 Oct 2019 17:18:11 -0700 Subject: bpf: Prepare btf_ctx_access for non raw_tp use case This patch makes a few changes to btf_ctx_access() to prepare it for non raw_tp use case where the attach_btf_id is not necessary a BTF_KIND_TYPEDEF. It moves the "btf_trace_" prefix check and typedef-follow logic to a new function "check_attach_btf_id()" which is called only once during bpf_check(). btf_ctx_access() only operates on a BTF_KIND_FUNC_PROTO type now. That should also be more efficient since it is done only one instead of every-time check_ctx_access() is called. "check_attach_btf_id()" needs to find the func_proto type from the attach_btf_id. It needs to store the result into the newly added prog->aux->attach_func_proto. func_proto btf type has no name, so a proper name should be stored into "attach_func_name" also. v2: - Move the "btf_trace_" check to an earlier verifier phase (Alexei) Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20191025001811.1718491-1-kafai@fb.com --- kernel/bpf/btf.c | 73 ++++++++++---------------------------------------------- 1 file changed, 13 insertions(+), 60 deletions(-) (limited to 'kernel/bpf/btf.c') diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index f7557af39756..128d89601d73 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -336,16 +336,6 @@ static bool btf_type_is_fwd(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; } -static bool btf_type_is_func(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC; -} - -static bool btf_type_is_func_proto(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO; -} - static bool btf_type_nosize(const struct btf_type *t) { return btf_type_is_void(t) || btf_type_is_fwd(t) || @@ -377,16 +367,6 @@ static bool btf_type_is_array(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; } -static bool btf_type_is_ptr(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_PTR; -} - -static bool btf_type_is_int(const struct btf_type *t) -{ - return BTF_INFO_KIND(t->info) == BTF_KIND_INT; -} - static bool btf_type_is_var(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_VAR; @@ -3442,54 +3422,27 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { + const struct btf_type *t = prog->aux->attach_func_proto; + const char *tname = prog->aux->attach_func_name; struct bpf_verifier_log *log = info->log; - u32 btf_id = prog->aux->attach_btf_id; const struct btf_param *args; - const struct btf_type *t; - const char prefix[] = "btf_trace_"; - const char *tname; u32 nr_args, arg; - if (!btf_id) - return true; - - if (IS_ERR(btf_vmlinux)) { - bpf_log(log, "btf_vmlinux is malformed\n"); - return false; - } - - t = btf_type_by_id(btf_vmlinux, btf_id); - if (!t || BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) { - bpf_log(log, "btf_id is invalid\n"); - return false; - } - - tname = __btf_name_by_offset(btf_vmlinux, t->name_off); - if (strncmp(prefix, tname, sizeof(prefix) - 1)) { - bpf_log(log, "btf_id points to wrong type name %s\n", tname); - return false; - } - tname += sizeof(prefix) - 1; - - t = btf_type_by_id(btf_vmlinux, t->type); - if (!btf_type_is_ptr(t)) - return false; - t = btf_type_by_id(btf_vmlinux, t->type); - if (!btf_type_is_func_proto(t)) - return false; - if (off % 8) { - bpf_log(log, "raw_tp '%s' offset %d is not multiple of 8\n", + bpf_log(log, "func '%s' offset %d is not multiple of 8\n", tname, off); return false; } arg = off / 8; args = (const struct btf_param *)(t + 1); - /* skip first 'void *__data' argument in btf_trace_##name typedef */ - args++; - nr_args = btf_type_vlen(t) - 1; + nr_args = btf_type_vlen(t); + if (prog->aux->attach_btf_trace) { + /* skip first 'void *__data' argument in btf_trace_##name typedef */ + args++; + nr_args--; + } if (arg >= nr_args) { - bpf_log(log, "raw_tp '%s' doesn't have %d-th argument\n", + bpf_log(log, "func '%s' doesn't have %d-th argument\n", tname, arg); return false; } @@ -3503,7 +3456,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, return true; if (!btf_type_is_ptr(t)) { bpf_log(log, - "raw_tp '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", + "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", tname, arg, __btf_name_by_offset(btf_vmlinux, t->name_off), btf_kind_str[BTF_INFO_KIND(t->info)]); @@ -3526,11 +3479,11 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, t = btf_type_by_id(btf_vmlinux, t->type); if (!btf_type_is_struct(t)) { bpf_log(log, - "raw_tp '%s' arg%d type %s is not a struct\n", + "func '%s' arg%d type %s is not a struct\n", tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]); return false; } - bpf_log(log, "raw_tp '%s' arg%d has btf_id %d type %s '%s'\n", + bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n", tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)], __btf_name_by_offset(btf_vmlinux, t->name_off)); return true; -- cgit v1.2.3-59-g8ed1b