From 9a19371bf029d784aa37ee623ce175205f43ccfd Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 22 Apr 2020 18:24:56 +0200 Subject: [PATCH] mptcp: fix data_fin handing in RX path The data fin flag is set only via a DSS option, but mptcp_incoming_options() copies it unconditionally from the provided RX options. Since we do not clear all the mptcp sock RX options in a socket free/alloc cycle, we can end-up with a stray data_fin value while parsing e.g. MPC packets. That would lead to mapping data corruption and will trigger a few WARN_ON() in the RX path. Instead of adding a costly memset(), fetch the data_fin flag only for DSS packets - when we always explicitly initialize such bit at option parsing time. Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path") Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/mptcp/options.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index faf57585b892..4a7c467b99db 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -876,12 +876,11 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb, mpext->data_seq = mp_opt->data_seq; mpext->subflow_seq = mp_opt->subflow_seq; mpext->dsn64 = mp_opt->dsn64; + mpext->data_fin = mp_opt->data_fin; } mpext->data_len = mp_opt->data_len; mpext->use_map = 1; } - - mpext->data_fin = mp_opt->data_fin; } void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts) -- 2.20.1