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| author | Paolo Abeni <pabeni@redhat.com> | 2023-07-04 22:44:34 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-07-05 10:51:14 +0100 |
| commit | 0226436acf2495cde4b93e7400e5a87305c26054 (patch) | |
| tree | 97023eff199cd0b3adaae7eea9d4aa47ec24c505 | |
| parent | 3fffa15bfef48b0ad6424779c03e68ae8ace5acb (diff) | |
| download | linux-pm-0226436acf2495cde4b93e7400e5a87305c26054.tar.gz | |
mptcp: do not rely on implicit state check in mptcp_listen()
Since the blamed commit, closing the first subflow resets the first
subflow socket state to SS_UNCONNECTED.
The current mptcp listen implementation relies only on such
state to prevent touching not-fully-disconnected sockets.
Incoming mptcp fastclose (or paired endpoint removal) unconditionally
closes the first subflow.
All the above allows an incoming fastclose followed by a listen() call
to successfully race with a blocking recvmsg(), potentially causing the
latter to hit a divide by zero bug in cleanup_rbuf/__tcp_select_window().
Address the issue explicitly checking the msk socket state in
mptcp_listen(). An alternative solution would be moving the first
subflow socket state update into mptcp_disconnect(), but in the long
term the first subflow socket should be removed: better avoid relaying
on it for internal consistency check.
Fixes: b29fcfb54cd7 ("mptcp: full disconnect implementation")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/414
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/mptcp/protocol.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 489a3defdde5c1..3613489eb6e3b0 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3703,6 +3703,11 @@ static int mptcp_listen(struct socket *sock, int backlog) pr_debug("msk=%p", msk); lock_sock(sk); + + err = -EINVAL; + if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM) + goto unlock; + ssock = __mptcp_nmpc_socket(msk); if (IS_ERR(ssock)) { err = PTR_ERR(ssock); |