From: MoYuanhao <moyuanhao3676@xxxxxxx>
Ensure there is enough space before adding MPTCP options in
tcp_syn_options().
Without this check, 'remaining' could underflow, and causes issues. If
there is not enough space, MPTCP should not be used.
Signed-off-by: MoYuanhao <moyuanhao3676@xxxxxxx>
Fixes: cec37a6e41aa ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
[ Matt: Add Fixes, cc Stable, update Description ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/ipv4/tcp_output.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 5485a70b5fe5a6039d19f4321c3c2ec8ecc6ffea..0e5b9a654254b32907ee9739f3443791104bd611 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -883,8 +883,10 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
unsigned int size;
if (mptcp_syn_options(sk, skb, &size, &opts->mptcp)) {
- opts->options |= OPTION_MPTCP;
- remaining -= size;
+ if (remaining >= size) {
+ opts->options |= OPTION_MPTCP;
+ remaining -= size;
+ }
}
}
---
base-commit: 09310cfd4ea5c3ab2c7a610420205e0a1660bf7e
change-id: 20241209-net-mptcp-check-space-syn-5694196ffb5f
Best regards,
--
Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
