From: Paolo Abeni pabeni@redhat.com

mainline inclusion from mainline-v6.10-rc4 commit 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACQHR CVE: CVE-2024-40931

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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@kernel.org Fixes: 8fd738049ac3 ("mptcp: fallback in case of simultaneous connect") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch cpaasch@apple.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/485 Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://lore.kernel.org/r/20240607-upstream-net-20240607-misc-fixes-v1-1-1ab... Signed-off-by: Jakub Kicinski kuba@kernel.org

Conflicts: net/mptcp/protocol.c [The conflict occurs because the commit 54f1944ed6d2("mptcp: factor out mptcp_connect()") and 7439d687b79c("mptcp: avoid a few atomic ops in the rx path") are not merged] Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- net/mptcp/protocol.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 613442057a04..c876f93f5b17 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2649,6 +2649,7 @@ 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, subflow->idsn);

do_connect: err = ssock->ops->connect(ssock, uaddr, addr_len, flags);