From 72aba03ba836c7b72b29cbec1c8ddc61b57edada Mon Sep 17 00:00:00 2001 From: Matthieu Baerts Date: Thu, 6 Jan 2022 14:06:36 -0800 Subject: [PATCH] mptcp: fix opt size when sending DSS + MP_FAIL [ Upstream commit 04fac2cae9422a3401c172571afbcfdd58fa5c7e ] When these two options had to be sent -- which is not common -- the DSS size was not being taken into account in the remaining size. Additionally in this situation, the reported size was only the one of the MP_FAIL which can cause issue if at the end, we need to write more in the TCP options than previously said. Here we use a dedicated variable for MP_FAIL size to keep the WARN_ON_ONCE() just after. Fixes: c25aeb4e0953 ("mptcp: MP_FAIL suboption sending") Acked-and-tested-by: Geliang Tang Signed-off-by: Matthieu Baerts Signed-off-by: Mat Martineau Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/mptcp/options.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 0966855..f69a1ca 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -823,10 +823,13 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts)) ret = true; else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) { + unsigned int mp_fail_size; + ret = true; - if (mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) { - *size += opt_size; - remaining -= opt_size; + if (mptcp_established_options_mp_fail(sk, &mp_fail_size, + remaining - opt_size, opts)) { + *size += opt_size + mp_fail_size; + remaining -= opt_size - mp_fail_size; return true; } } -- 2.7.4