From 3855729e8bf82f10160a61dae0ab5f5b1e8c795f Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Thu, 13 Jun 2024 07:52:01 +0000 Subject: [PATCH] net: rds: fix memory leak in rds_recvmsg MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit stable inclusion from stable-v5.10.46 commit 5946fbf48355f5a8caeff72580c7658da5966b86 bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4HY CVE: CVE-2021-47249 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5946fbf48355f5a8caeff72580c7658da5966b86 -------------------------------- [ 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@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Reviewed-by: Håkon Bugge Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Chen Jun Acked-by: Weilong Chen Signed-off-by: Zheng Zengkai Signed-off-by: Zheng Zucheng --- 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 3ca278988b52..ccf0bf283002 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -705,7 +705,7 @@ 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); -- Gitee