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| author | Cong Wang <cong.wang@bytedance.com> | 2021-07-23 21:36:30 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-07-30 22:40:55 +0300 |
| commit | 0b846445985895e75958ecd59061fd7bf77e0c3f (patch) | |
| tree | 47178f8be372abbc3a48077329f45c5cfaf2fc5a /net/unix | |
| parent | a710eed386f182fcbfe517b659f60024fdb7c40c (diff) | |
| download | linux-0b846445985895e75958ecd59061fd7bf77e0c3f.tar.xz | |
unix_bpf: Fix a potential deadlock in unix_dgram_bpf_recvmsg()
As Eric noticed, __unix_dgram_recvmsg() may acquire u->iolock
too, so we have to release it before calling this function.
Fixes: 9825d866ce0d ("af_unix: Implement unix_dgram_bpf_recvmsg()")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Diffstat (limited to 'net/unix')
| -rw-r--r-- | net/unix/unix_bpf.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c index db0cda29fb2f..177e883f451e 100644 --- a/net/unix/unix_bpf.c +++ b/net/unix/unix_bpf.c @@ -44,7 +44,7 @@ static int unix_dgram_bpf_recvmsg(struct sock *sk, struct msghdr *msg, { struct unix_sock *u = unix_sk(sk); struct sk_psock *psock; - int copied, ret; + int copied; psock = sk_psock_get(sk); if (unlikely(!psock)) @@ -53,8 +53,9 @@ static int unix_dgram_bpf_recvmsg(struct sock *sk, struct msghdr *msg, mutex_lock(&u->iolock); if (!skb_queue_empty(&sk->sk_receive_queue) && sk_psock_queue_empty(psock)) { - ret = __unix_dgram_recvmsg(sk, msg, len, flags); - goto out; + mutex_unlock(&u->iolock); + sk_psock_put(sk, psock); + return __unix_dgram_recvmsg(sk, msg, len, flags); } msg_bytes_ready: @@ -68,16 +69,15 @@ msg_bytes_ready: if (data) { if (!sk_psock_queue_empty(psock)) goto msg_bytes_ready; - ret = __unix_dgram_recvmsg(sk, msg, len, flags); - goto out; + mutex_unlock(&u->iolock); + sk_psock_put(sk, psock); + return __unix_dgram_recvmsg(sk, msg, len, flags); } copied = -EAGAIN; } - ret = copied; -out: mutex_unlock(&u->iolock); sk_psock_put(sk, psock); - return ret; + return copied; } static struct proto *unix_prot_saved __read_mostly; |