From: Pavel Skripkin <paskripkin@xxxxxxxxx>
[ Upstream commit 49bfcbfd989a8f1f23e705759a6bb099de2cff9f ]
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Reviewed-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx>
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 aba4afe4dfed..967d115f97ef 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);
--
2.30.2
