diff options
| author | Teng Qin <qinteng@fb.com> | 2017-04-24 19:00:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-16 10:06:46 +0200 |
| commit | ea7c24c78551c8b3e6a7e9824e5ad8ba6224f5fe (patch) | |
| tree | 7eeb4fdc46d9a20b13f55a0aa8806611c8650021 /kernel/bpf/syscall.c | |
| parent | 609124d60341bf8870318c201cec50548824f2e2 (diff) | |
bpf: map_get_next_key to return first key on NULL
commit 8fe45924387be6b5c1be59a7eb330790c61d5d10 upstream.
When iterating through a map, we need to find a key that does not exist
in the map so map_get_next_key will give us the first key of the map.
This often requires a lot of guessing in production systems.
This patch makes map_get_next_key return the first key when the key
pointer in the parameter is NULL.
Signed-off-by: Teng Qin <qinteng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chenbo Feng <fengc@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index dc19b6e210e6..4b9bbfe764e8 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -390,14 +390,18 @@ static int map_get_next_key(union bpf_attr *attr) if (IS_ERR(map)) return PTR_ERR(map); - err = -ENOMEM; - key = kmalloc(map->key_size, GFP_USER); - if (!key) - goto err_put; - - err = -EFAULT; - if (copy_from_user(key, ukey, map->key_size) != 0) - goto free_key; + if (ukey) { + err = -ENOMEM; + key = kmalloc(map->key_size, GFP_USER); + if (!key) + goto err_put; + + err = -EFAULT; + if (copy_from_user(key, ukey, map->key_size) != 0) + goto free_key; + } else { + key = NULL; + } err = -ENOMEM; next_key = kmalloc(map->key_size, GFP_USER); |