From: Paolo Abeni <pabeni@xxxxxxxxxx>
commit 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 upstream.
This is strictly related to commit fb7a0d334894 ("mptcp: ensure snd_nxt
is properly initialized on connect"). It turns out that syzkaller can
trigger the retransmit after fallback and before processing any other
incoming packet - so that snd_una is still left uninitialized.
Address the issue explicitly initializing snd_una together with snd_nxt
and write_seq.
Suggested-by: Mat Martineau <martineau@xxxxxxxxxx>
Fixes: 8fd738049ac3 ("mptcp: fallback in case of simultaneous connect")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Christoph Paasch <cpaasch@xxxxxxxxx>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/485
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240607-upstream-net-20240607-misc-fixes-v1-1-1ab9ddfa3d00@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
[ Conflicts in protocol.c, similar to the ones from commit 99951b62bf20
("mptcp: ensure snd_nxt is properly initialized on connect"), with the
same resolution. Note that in this version, 'snd_una' is an atomic64
type, so use atomic64_set() instead, as it is done everywhere else. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/mptcp/protocol.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 36fa456f42ba..a36493bbf895 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2646,6 +2646,7 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
mptcp_subflow_early_fallback(msk, subflow);
WRITE_ONCE(msk->write_seq, subflow->idsn);
+ atomic64_set(&msk->snd_una, msk->write_seq);
do_connect:
err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
--
2.43.0
