Messages in this thread Patch in this message | | | From | Pavel Skripkin <> | Subject | [PATCH] net: rds: fix memory leak in rds_recvmsg | Date | Mon, 7 Jun 2021 22:41:02 +0300 |
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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 <paskripkin@gmail.com> --- net/rds/recv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/rds/recv.c b/net/rds/recv.c index 4db109fb6ec2..3fa16c339bfe 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; + goto out_put; } rds_recvmsg_zcookie(rs, msg); @@ -740,6 +740,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, break; } +out_put: if (inc) rds_inc_put(inc); -- 2.31.1
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