[PATCH net v2 03/15] mptcp: syncookies: remember the request backup flag
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: 2026-09-08 14:14:25
Also in:
lkml, netdev, stable
Subsystem:
networking [general], networking [mptcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthieu Baerts, Mat Martineau, Linus Torvalds
Instead of using an uninitialised bit when copying the info in
subflow_ulp_clone().
To fix this, no need to extend the join_entry structure: backup is
coming from struct mptcp_subflow_request_sock, only one bit. Do the same
here by using one bit for both.
Fixes: efd340bf3d77 ("mptcp: distinguish rcv vs sent backup flag in requests")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
v2: update the Fixes tag (even if the target version is the same)
---
net/mptcp/syncookies.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/mptcp/syncookies.c b/net/mptcp/syncookies.c
index b5cac5701122..9474706641c1 100644
--- a/net/mptcp/syncookies.c
+++ b/net/mptcp/syncookies.c@@ -26,7 +26,8 @@ struct join_entry { u32 local_nonce; u8 join_id; u8 local_id; - u8 backup; + u8 backup:1, + request_bkup:1; u8 valid; };
@@ -63,6 +64,7 @@ static void mptcp_join_store_state(struct join_entry *entry, entry->remote_nonce = subflow_req->remote_nonce; entry->local_nonce = subflow_req->local_nonce; entry->backup = subflow_req->backup; + entry->request_bkup = subflow_req->request_bkup; entry->join_id = subflow_req->remote_id; entry->local_id = subflow_req->local_id; entry->valid = 1;
@@ -117,6 +119,7 @@ bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subfl subflow_req->remote_nonce = e->remote_nonce; subflow_req->local_nonce = e->local_nonce; subflow_req->backup = e->backup; + subflow_req->request_bkup = e->request_bkup; subflow_req->remote_id = e->join_id; subflow_req->local_id = e->local_id; subflow_req->token = e->token;
--
2.55.0