From: Dmitrii Banshchikov me@ubique.spb.ru
mainline inclusion from mainline-5.13-rc1 commit 523a4cf491b3c9e2d546040d57250f1a0ca84f03 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-------------------------------------------------
Instead of using integer literal here and there use macro name for better context.
Signed-off-by: Dmitrii Banshchikov me@ubique.spb.ru Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Martin KaFai Lau kafai@fb.com Link: https://lore.kernel.org/bpf/20210225202629.585485-1-me@ubique.spb.ru (cherry picked from commit 523a4cf491b3c9e2d546040d57250f1a0ca84f03) Signed-off-by: Wang Yufen wangyufen@huawei.com --- include/linux/bpf.h | 5 +++++ kernel/bpf/btf.c | 25 ++++++++++++++----------- kernel/bpf/verifier.c | 2 +- 3 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a6f0daa55096..f532d9f61d26 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -573,6 +573,11 @@ enum bpf_cgroup_storage_type { */ #define MAX_BPF_FUNC_ARGS 12
+/* The maximum number of arguments passed through registers + * a single function may have. + */ +#define MAX_BPF_FUNC_REG_ARGS 5 + struct btf_func_model { u8 ret_size; u8 nr_args; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 0fbd024a90f3..ab190f20e811 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4591,8 +4591,10 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } arg = off / 8; args = (const struct btf_param *)(t + 1); - /* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */ - nr_args = t ? btf_type_vlen(t) : 5; + /* if (t == NULL) Fall back to default BPF prog with + * MAX_BPF_FUNC_REG_ARGS u64 arguments. + */ + nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS; if (prog->aux->attach_btf_trace) { /* skip first 'void *__data' argument in btf_trace_##name typedef */ args++; @@ -4649,7 +4651,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } } else { if (!t) - /* Default prog with 5 args */ + /* Default prog with MAX_BPF_FUNC_REG_ARGS args */ return true; t = btf_type_by_id(btf, args[arg].type); } @@ -5102,12 +5104,12 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
if (!func) { /* BTF function prototype doesn't match the verifier types. - * Fall back to 5 u64 args. + * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args. */ - for (i = 0; i < 5; i++) + for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) m->arg_size[i] = 8; m->ret_size = 8; - m->nr_args = 5; + m->nr_args = MAX_BPF_FUNC_REG_ARGS; return 0; } args = (const struct btf_param *)(func + 1); @@ -5342,8 +5344,9 @@ int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, } args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); - if (nargs > 5) { - bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs); + if (nargs > MAX_BPF_FUNC_REG_ARGS) { + bpf_log(log, "Function %s has %d > %d args\n", tname, nargs, + MAX_BPF_FUNC_REG_ARGS); goto out; }
@@ -5472,9 +5475,9 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, } args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); - if (nargs > 5) { - bpf_log(log, "Global function %s() with %d > 5 args. Buggy compiler.\n", - tname, nargs); + if (nargs > MAX_BPF_FUNC_REG_ARGS) { + bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n", + tname, nargs, MAX_BPF_FUNC_REG_ARGS); return -EINVAL; } /* check that function returns int */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f3c20e763156..a0c3205760aa 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5531,7 +5531,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
meta.func_id = func_id; /* check args */ - for (i = 0; i < 5; i++) { + for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) { err = check_func_arg(env, i, &meta, fn); if (err) return err;