Merge branch 'net-x25-fix-overflow-and-double-free'

Martin Schiller says:

====================
net/x25: Fix overflow and double free

This patch set includes 2 fixes:

The first removes a potential double free of received skb
The second fixes an overflow when accumulating packets with the more-bit
set.

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
====================

Link: https://patch.msgid.link/20260331-x25_fraglen-v4-0-3e69f18464b4@dev.tdt.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

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);
@@ -44,10 +48,9 @@ static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
 	if (x25->fraglen > 0) {	/* End of fragment */
 		int len = x25->fraglen + skb->len;
 
-		if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
-			kfree_skb(skb);
+		skbn = alloc_skb(len, GFP_ATOMIC);
+		if (!skbn)
 			return 1;
-		}
 
 		skb_queue_tail(&x25->fragment_queue, skb);
 

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;
 }