diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 656ee11aff67..a91822bae043 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6383,12 +6383,11 @@ struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog) return prog->aux->attach_btf; } -static bool is_int_ptr(struct btf *btf, const struct btf_type *t) +static bool is_void_or_int_ptr(struct btf *btf, const struct btf_type *t) { /* skip modifiers */ t = btf_type_skip_modifiers(btf, t->type, NULL); - - return btf_type_is_int(t); + return btf_type_is_void(t) || btf_type_is_int(t); } static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto, @@ -6776,14 +6775,11 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } } - if (t->type == 0) - /* This is a pointer to void. - * It is the same as scalar from the verifier safety pov. - * No further pointer walking is allowed. - */ - return true; - - if (is_int_ptr(btf, t)) + /* + * If it's a pointer to void, it's the same as scalar from the verifier + * safety POV. Either way, no futher pointer walking is allowed. + */ + if (is_void_or_int_ptr(btf, t)) return true; /* this is a pointer to another type */ diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 7cb192cbd65f..aaf13a7d58ed 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -569,6 +569,11 @@ __bpf_kfunc u32 bpf_fentry_test9(u32 *a) return *a; } +int noinline bpf_fentry_test10(const void *a) +{ + return (long)a; +} + void noinline bpf_fentry_test_sinfo(struct skb_shared_info *sinfo) { } @@ -699,7 +704,8 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 || bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 || bpf_fentry_test8(&arg) != 0 || - bpf_fentry_test9(&retval) != 0) + bpf_fentry_test9(&retval) != 0 || + bpf_fentry_test10((void *)0) != 0) goto out; break; case BPF_MODIFY_RETURN: diff --git a/tools/testing/selftests/bpf/progs/verifier_btf_ctx_access.c b/tools/testing/selftests/bpf/progs/verifier_btf_ctx_access.c index 28b939572cda..03942cec07e5 100644 --- a/tools/testing/selftests/bpf/progs/verifier_btf_ctx_access.c +++ b/tools/testing/selftests/bpf/progs/verifier_btf_ctx_access.c @@ -65,4 +65,16 @@ __naked void ctx_access_u32_pointer_reject_8(void) " ::: __clobber_all); } +SEC("fentry/bpf_fentry_test10") +__description("btf_ctx_access const void pointer accept") +__success __retval(0) +__naked void ctx_access_const_void_pointer_accept(void) +{ + asm volatile (" \ + r2 = *(u64 *)(r1 + 0); /* load 1st argument value (const void pointer) */\ + r0 = 0; \ + exit; \ +" ::: __clobber_all); +} + char _license[] SEC("license") = "GPL";