From a1822cb524e89b4cd2cf0b82e484a2335496a6d9 Mon Sep 17 00:00:00 2001 From: Martin Schiller Date: Tue, 31 Mar 2026 09:43:18 +0200 Subject: [PATCH] net/x25: Fix overflow when accumulating packets Add a check to ensure that `x25_sock.fraglen` does not overflow. The `fraglen` also needs to be resetted when purging `fragment_queue` in `x25_clear_queues()`. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Suggested-by: Yiming Qian Signed-off-by: Martin Schiller Link: https://patch.msgid.link/20260331-x25_fraglen-v4-2-3e69f18464b4@dev.tdt.de Signed-off-by: Paolo Abeni --- net/x25/x25_in.c | 4 ++++ net/x25/x25_subr.c | 1 + 2 files changed, 5 insertions(+) diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c index 0dbc73efab1c..e47ebd8acd21 100644 --- a/net/x25/x25_in.c +++ b/net/x25/x25_in.c @@ -34,6 +34,10 @@ static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) struct sk_buff *skbo, *skbn = skb; struct x25_sock *x25 = x25_sk(sk); + /* make sure we don't overflow */ + if (x25->fraglen + skb->len > USHRT_MAX) + return 1; + if (more) { x25->fraglen += skb->len; skb_queue_tail(&x25->fragment_queue, skb); diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c index 0285aaa1e93c..159708d9ad20 100644 --- a/net/x25/x25_subr.c +++ b/net/x25/x25_subr.c @@ -40,6 +40,7 @@ void x25_clear_queues(struct sock *sk) skb_queue_purge(&x25->interrupt_in_queue); skb_queue_purge(&x25->interrupt_out_queue); skb_queue_purge(&x25->fragment_queue); + x25->fraglen = 0; }