This is a note to let you know that I've just added the patch titled tcp: Fix use-after-free of nreq in reqsk_timer_handler(). to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-fix-use-after-free-of-nreq-in-reqsk_timer_handle.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2736ec7d6fa314c6b5de202986bfc6bbd9b1e113 Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Sat Nov 23 09:42:36 2024 -0800 tcp: Fix use-after-free of nreq in reqsk_timer_handler(). [ Upstream commit c31e72d021db2714df03df6c42855a1db592716c ] The cited commit replaced inet_csk_reqsk_queue_drop_and_put() with __inet_csk_reqsk_queue_drop() and reqsk_put() in reqsk_timer_handler(). Then, oreq should be passed to reqsk_put() instead of req; otherwise use-after-free of nreq could happen when reqsk is migrated but the retry attempt failed (e.g. due to timeout). Let's pass oreq to reqsk_put(). Fixes: e8c526f2bdf1 ("tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().") Reported-by: Liu Jian <liujian56@xxxxxxxxxx> Closes: https://lore.kernel.org/netdev/1284490f-9525-42ee-b7b8-ccadf6606f6d@xxxxxxxxxx/ Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Reviewed-by: Vadim Fedorenko <vadim.fedorenko@xxxxxxxxx> Reviewed-by: Liu Jian <liujian56@xxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reviewed-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx> Link: https://patch.msgid.link/20241123174236.62438-1-kuniyu@xxxxxxxxxx Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 569186f741fb2..8fa56a17f03a6 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -1121,7 +1121,7 @@ static void reqsk_timer_handler(struct timer_list *t) drop: __inet_csk_reqsk_queue_drop(sk_listener, oreq, true); - reqsk_put(req); + reqsk_put(oreq); } static bool reqsk_queue_hash_req(struct request_sock *req,