Re: [PATCH v2] net: rds: fix memory leak in rds_recvmsg
From: Haakon Bugge <hidden>
Date: 2021-06-08 12:30:23
Also in:
linux-rdma, lkml
On 8 Jun 2021, at 10:06, Pavel Skripkin [off-list ref] wrote:
Syzbot reported memory leak in rds. The problem
was in unputted refcount in case of error.
int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
int msg_flags)
{
...
if (!rds_next_incoming(rs, &inc)) {
...
}
After this "if" inc refcount incremented and
if (rds_cmsg_recv(inc, msg, rs)) {
ret = -EFAULT;
goto out;
}
...
out:
return ret;
}
in case of rds_cmsg_recv() fail the refcount won't be
decremented. And it's easy to see from ftrace log, that
rds_inc_addref() don't have rds_inc_put() pair in
rds_recvmsg() after rds_cmsg_recv()
1) | rds_recvmsg() {
1) 3.721 us | rds_inc_addref();
1) 3.853 us | rds_message_inc_copy_to_user();
1) + 10.395 us | rds_cmsg_recv();
1) + 34.260 us | }
Fixes: bdbe6fbc6a2f ("RDS: recv.c")
Reported-and-tested-by: syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>Reviewed-by: Håkon Bugge <redacted> Thanks for fixing this, Håkon
quoted hunk ↗ jump to hunk
--- Changes in v2: Changed goto to break. --- net/rds/recv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/net/rds/recv.c b/net/rds/recv.c index 4db109fb6ec2..5b426dc3634d 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c@@ -714,7 +714,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; - goto out; + break; } rds_recvmsg_zcookie(rs, msg); -- 2.31.1