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| author | Florian Westphal <fw@strlen.de> | 2020-04-20 17:25:04 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-04-20 22:59:32 +0300 |
| commit | 5e20087d1b678965ae9df01eed03efedc1aef9f8 (patch) | |
| tree | 1f015fb82ba6d3be8ee01a146fd0698992c4bb2d /net/mptcp | |
| parent | bd019427bf3623ee3c7d2845cf921bbf4c14846c (diff) | |
| download | linux-5e20087d1b678965ae9df01eed03efedc1aef9f8.tar.xz | |
mptcp: handle mptcp listener destruction via rcu
Following splat can occur during self test:
BUG: KASAN: use-after-free in subflow_data_ready+0x156/0x160
Read of size 8 at addr ffff888100c35c28 by task mptcp_connect/4808
subflow_data_ready+0x156/0x160
tcp_child_process+0x6a3/0xb30
tcp_v4_rcv+0x2231/0x3730
ip_protocol_deliver_rcu+0x5c/0x860
ip_local_deliver_finish+0x220/0x360
ip_local_deliver+0x1c8/0x4e0
ip_rcv_finish+0x1da/0x2f0
ip_rcv+0xd0/0x3c0
__netif_receive_skb_one_core+0xf5/0x160
__netif_receive_skb+0x27/0x1c0
process_backlog+0x21e/0x780
net_rx_action+0x35f/0xe90
do_softirq+0x4c/0x50
[..]
This occurs when accessing subflow_ctx->conn.
Problem is that tcp_child_process() calls listen sockets'
sk_data_ready() notification, but it doesn't hold the listener
lock. Another cpu calling close() on the listener will then cause
transition of refcount to 0.
Fixes: 58b09919626bf ("mptcp: create msk early")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mptcp')
| -rw-r--r-- | net/mptcp/protocol.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 7e816c733ccb..b57974a6b6cc 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1378,6 +1378,7 @@ struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req) msk->ack_seq = ack_seq; } + sock_reset_flag(nsk, SOCK_RCU_FREE); /* will be fully established after successful MPC subflow creation */ inet_sk_state_store(nsk, TCP_SYN_RECV); bh_unlock_sock(nsk); @@ -1779,6 +1780,8 @@ static int mptcp_listen(struct socket *sock, int backlog) goto unlock; } + sock_set_flag(sock->sk, SOCK_RCU_FREE); + err = ssock->ops->listen(ssock, backlog); inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); if (!err) |