diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2023-03-21 13:38:52 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2023-03-22 09:31:05 -0700 |
| commit | 1057d299459657b85e593a4b6294a000f920672a (patch) | |
| tree | e962571e8ea2ef312a9b9584abac83db3ee98fa5 /kernel/bpf | |
| parent | a18f721415b4d4edea23cb8c7d6276330302af14 (diff) | |
bpf: Teach the verifier to recognize rdonly_mem as not null.
Teach the verifier to recognize PTR_TO_MEM | MEM_RDONLY as not NULL
otherwise if (!bpf_ksym_exists(known_kfunc)) doesn't go through
dead code elimination.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230321203854.3035-3-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8bc44f5dc5b6..5693e4a92752 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -486,8 +486,17 @@ static bool type_is_sk_pointer(enum bpf_reg_type type) type == PTR_TO_XDP_SOCK; } +static bool type_may_be_null(u32 type) +{ + return type & PTR_MAYBE_NULL; +} + static bool reg_type_not_null(enum bpf_reg_type type) { + if (type_may_be_null(type)) + return false; + + type = base_type(type); return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK || type == PTR_TO_MAP_VALUE || @@ -531,11 +540,6 @@ static bool type_is_rdonly_mem(u32 type) return type & MEM_RDONLY; } -static bool type_may_be_null(u32 type) -{ - return type & PTR_MAYBE_NULL; -} - static bool is_acquire_function(enum bpf_func_id func_id, const struct bpf_map *map) { |