[PATCH 5.10 104/157] mptcp: put subflow sock on connect error

Greg Kroah-Hartman
2021-03-22T12:53:41Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit f07157792c633b528de5fc1dbe2e4ea54f8e09d4 ]

mptcp_add_pending_subflow() performs a sock_hold() on the subflow,
then adds the subflow to the join list.

Without a sock_put the subflow sk won't be freed in case connect() fails.

unreferenced object 0xffff88810c03b100 (size 3000):
[..]
sk_prot_alloc.isra.0+0x2f/0x110
sk_alloc+0x5d/0xc20
inet6_create+0x2b7/0xd30
__sock_create+0x17f/0x410
mptcp_subflow_create_socket+0xff/0x9c0
__mptcp_subflow_connect+0x1da/0xaf0
mptcp_pm_nl_work+0x6e0/0x1120
mptcp_worker+0x508/0x9a0

Fixes: 5b950ff4331ddda ("mptcp: link MPC subflow into msk only after accept")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mptcp/subflow.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 16adba172fb9..591546d0953f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1133,6 +1133,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
spin_lock_bh(&msk->join_list_lock);
list_add_tail(&subflow->node, &msk->join_list);
spin_unlock_bh(&msk->join_list_lock);
+ sock_put(mptcp_subflow_tcp_sock(subflow));

return err;

--
2.30.1