[PATCH net] irda: fix a potential use-after-free in ircomm_param_request

[PATCH net] irda: fix a potential use-after-free in ircomm_param_request

[Cong Wang]

self->ctrl_skb is protected by self->spinlock, we should not
access it out of the lock. Move the debugging printk inside.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/irda/ircomm/ircomm_param.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/irda/ircomm/ircomm_param.c b/net/irda/ircomm/ircomm_param.c
index 3c4caa6..5728e76 100644
--- a/net/irda/ircomm/ircomm_param.c
+++ b/net/irda/ircomm/ircomm_param.c
@@ -134,11 +134,10 @@ int ircomm_param_request(struct ircomm_tty_cb *self, __u8 pi, int flush)
 		return -1;
 	}
 	skb_put(skb, count);
+	pr_debug("%s(), skb->len=%d\n", __func__, skb->len);
 
 	spin_unlock_irqrestore(&self->spinlock, flags);
 
-	pr_debug("%s(), skb->len=%d\n", __func__ , skb->len);
-
 	if (flush) {
 		/* ircomm_tty_do_softint will take care of the rest */
 		schedule_work(&self->tqueue);
-- 
1.8.3.1

Re: [PATCH net] irda: fix a potential use-after-free in ircomm_param_request

[David Miller]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Fri, 29 Jan 2016 11:58:03 -0800

> self->ctrl_skb is protected by self->spinlock, we should not
> access it out of the lock. Move the debugging printk inside.
> 
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Cc: Samuel Ortiz <samuel@sortiz.org>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Applied, thanks.