[PATCH] af_unix: Add OOB support
From: Rao Shoaib <hidden>
Date: 2021-08-10 18:31:43
From: Rao Shoaib <redacted>
syzkaller found that OOB code was holding spinlock
while calling a function in which it could sleep.
Reported-by: syzbot+8760ca6c1ee783ac4abd@syzkaller.appspotmail.com
Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Rao Shoaib <redacted>
---
net/unix/af_unix.c | 36 ++++++++++++++++++++++++------------
1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 00d8b08cdbe1..a626e52c629a 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -2362,19 +2362,37 @@ static int unix_stream_recv_urg(struct unix_stream_read_state *state) struct sock *sk = sock->sk; struct unix_sock *u = unix_sk(sk); int chunk = 1; + struct sk_buff *oob_skb; - if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) + mutex_lock(&u->iolock); + unix_state_lock(sk); + + if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) { + unix_state_unlock(sk); + mutex_unlock(&u->iolock); return -EINVAL; + } - chunk = state->recv_actor(u->oob_skb, 0, chunk, state); - if (chunk < 0) - return -EFAULT; + oob_skb = u->oob_skb; if (!(state->flags & MSG_PEEK)) { - UNIXCB(u->oob_skb).consumed += 1; - kfree_skb(u->oob_skb); u->oob_skb = NULL; } + + unix_state_unlock(sk); + + chunk = state->recv_actor(oob_skb, 0, chunk, state); + + if (!(state->flags & MSG_PEEK)) { + UNIXCB(oob_skb).consumed += 1; + kfree_skb(oob_skb); + } + + mutex_unlock(&u->iolock); + + if (chunk < 0) + return -EFAULT; + state->msg->msg_flags |= MSG_OOB; return 1; }
@@ -2434,13 +2452,7 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, if (unlikely(flags & MSG_OOB)) { err = -EOPNOTSUPP; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) - mutex_lock(&u->iolock); - unix_state_lock(sk); - err = unix_stream_recv_urg(state); - - unix_state_unlock(sk); - mutex_unlock(&u->iolock); #endif goto out; }
--
2.27.0