diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2026-06-01 17:02:43 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-01 18:36:40 -0700 |
| commit | c48c3a7e7d5bed644208ed443d63bb6a6f411676 (patch) | |
| tree | 0adfdb88c4df321214e314ab1b9680aa794a8ccc /kernel | |
| parent | 9a3c3c49c333760c8944dadacbe114c1884546ef (diff) | |
bpf: Drop redundant hash_buf from map_get_hash operation
bpf_map_get_info_by_fd() is the only caller of the ->map_get_hash
and always invokes it with hash_buf == map->sha and hash_buf_size
of SHA256_DIGEST_SIZE. array_map_get_hash() in turn lets sha256()
write the digest directly into that buffer (map->sha) and then
performs a trailing memcpy(), which evaluates to memcpy(map->sha,
map->sha, 32): a redundant self-copy. The hash_buf_size argument
was never used at all. Simplify this a bit, no functional change.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260601150248.394863-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/arraymap.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 8 |
2 files changed, 5 insertions, 9 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index dfb2110ab733..e6271a2bf6d6 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -175,14 +175,12 @@ static void *array_map_lookup_elem(struct bpf_map *map, void *key) return array->value + (u64)array->elem_size * (index & array->index_mask); } -static int array_map_get_hash(struct bpf_map *map, u32 hash_buf_size, - void *hash_buf) +static int array_map_get_hash(struct bpf_map *map) { struct bpf_array *array = container_of(map, struct bpf_array, map); sha256(array->value, (u64)array->elem_size * array->map.max_entries, - hash_buf); - memcpy(array->map.sha, hash_buf, sizeof(array->map.sha)); + array->map.sha); return 0; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2aafd2131983..a27fa2b9b405 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5434,18 +5434,16 @@ static int bpf_map_get_info_by_fd(struct file *file, if (!map->ops->map_get_hash) return -EINVAL; - - if (info.hash_size != SHA256_DIGEST_SIZE) + if (info.hash_size != sizeof(map->sha)) return -EINVAL; - if (!READ_ONCE(map->frozen)) return -EPERM; - err = map->ops->map_get_hash(map, SHA256_DIGEST_SIZE, map->sha); + err = map->ops->map_get_hash(map); if (err != 0) return err; - if (copy_to_user(uhash, map->sha, SHA256_DIGEST_SIZE) != 0) + if (copy_to_user(uhash, map->sha, sizeof(map->sha)) != 0) return -EFAULT; } else if (info.hash_size) { return -EINVAL; |