ax25: Fix NULL pointer dereference and lockup. (7dccf1f4) · Commits · 戴 / test

From: Jarek Poplawski <jarkao2@gmail.com> There is only one function in AX25 calling skb_append(), and it really looks suspicious: appends skb after previously enqueued one, but in the meantime this previous skb could be removed from the queue. This patch Fixes it the simple way, so this is not fully compatible with the current method, but testing hasn't shown any problems. Signed-off-by:

Ralf Baechle <ralf@linux-mips.org> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ax25/ax25_subr.c

+3 −8

Original line number	Diff line number	Diff line
		@@ -64,20 +64,15 @@ void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)

		void ax25_requeue_frames(ax25_cb *ax25)
		{
		struct sk_buff skb, skb_prev = NULL;
		struct sk_buff *skb;

		/*
		* Requeue all the un-ack-ed frames on the output queue to be picked
		* up by ax25_kick called from the timer. This arrangement handles the
		* possibility of an empty output queue.
		*/
		while ((skb = skb_dequeue(&ax25->ack_queue)) != NULL) {
		if (skb_prev == NULL)
		while ((skb = skb_dequeue_tail(&ax25->ack_queue)) != NULL)
		skb_queue_head(&ax25->write_queue, skb);
		else
		skb_append(skb_prev, skb, &ax25->write_queue);
		skb_prev = skb;
		}
		}

		/*

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