From: Cong Wang <xiyou.wangcong@gmail.com>
To: netdev@vger.kernel.org
Cc: Cong Wang <cong.wang@bytedance.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
John Fastabend <john.fastabend@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Jakub Sitnicki <jakub@cloudflare.com>,
Lorenz Bauer <lmb@cloudflare.com>
Subject: [Patch bpf-next] unix_bpf: fix a potential deadlock in unix_dgram_bpf_recvmsg()
Date: Fri, 23 Jul 2021 11:36:30 -0700 [thread overview]
Message-ID: <20210723183630.5088-1-xiyou.wangcong@gmail.com> (raw)
From: Cong Wang <cong.wang@bytedance.com>
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>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
net/unix/unix_bpf.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c
index db0cda29fb2f..b07cb30e87b1 100644
--- a/net/unix/unix_bpf.c
+++ b/net/unix/unix_bpf.c
@@ -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:
@@ -68,13 +69,13 @@ static int unix_dgram_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
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;
--
2.27.0
next reply other threads:[~2021-07-23 18:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-23 18:36 Cong Wang [this message]
2021-07-27 16:12 ` [Patch bpf-next] unix_bpf: fix a potential deadlock in unix_dgram_bpf_recvmsg() John Fastabend
2021-07-28 3:06 ` Cong Wang
2021-07-28 10:12 ` Jakub Sitnicki
2021-07-28 18:52 ` John Fastabend
2021-07-30 19:45 ` Andrii Nakryiko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210723183630.5088-1-xiyou.wangcong@gmail.com \
--to=xiyou.wangcong@gmail.com \
--cc=cong.wang@bytedance.com \
--cc=daniel@iogearbox.net \
--cc=eric.dumazet@gmail.com \
--cc=jakub@cloudflare.com \
--cc=john.fastabend@gmail.com \
--cc=lmb@cloudflare.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).