diff options
| author | Cong Wang <cong.wang@bytedance.com> | 2024-10-26 11:55:22 -0700 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2024-10-28 18:44:14 -0700 |
| commit | 740be3b9a6d73336f8c7d540842d0831dc7a808b (patch) | |
| tree | f5d0b5fda3e2c0938f1e59d42010f265f4a39323 /net | |
| parent | ae90f6a6170d7a7a1aa4fddf664fbd093e3023bc (diff) | |
sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()
The following race condition could trigger a NULL pointer dereference:
sock_map_link_detach(): sock_map_link_update_prog():
mutex_lock(&sockmap_mutex);
...
sockmap_link->map = NULL;
mutex_unlock(&sockmap_mutex);
mutex_lock(&sockmap_mutex);
...
sock_map_prog_link_lookup(sockmap_link->map);
mutex_unlock(&sockmap_mutex);
<continue>
Fix it by adding a NULL pointer check. In this specific case, it makes
no sense to update a link which is being released.
Reported-by: Ruan Bonan <bonan.ruan@u.nus.edu>
Fixes: 699c23f02c65 ("bpf: Add bpf_link support for sk_msg and sk_skb progs")
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/r/20241026185522.338562-1-xiyou.wangcong@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/sock_map.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 07d6aa4e39ef..78347d7d25ef 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1760,6 +1760,10 @@ static int sock_map_link_update_prog(struct bpf_link *link, ret = -EINVAL; goto out; } + if (!sockmap_link->map) { + ret = -ENOLINK; + goto out; + } ret = sock_map_prog_link_lookup(sockmap_link->map, &pprog, &plink, sockmap_link->attach_type); |