[PATCH 1/2] [stable pre-4.12] can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once

[PATCH 1/2] [stable pre-4.12] can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once

[Oliver Hartkopp]

In Linux 4.12 commit 8e8cda6d737d356054c ("can: initial support for network
namespaces") removed a namespace check which affected this patch:

upstream commit 8cb68751c115d176ec851ca56ecfbb411568c9e8

can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once

If an invalid CAN frame is received, from a driver or from a tun
interface, a Kernel warning is generated.

This patch replaces the WARN_ONCE by a simple pr_warn_once, so that a
kernel, bootet with panic_on_warn, does not panic. A printk seems to be
more appropriate here.

Reported-by: syzbot+4386709c0c1284dca827@syzkaller.appspotmail.com
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org> [pre 4.12]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/af_can.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 928f58064098..924ad0513af9 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -722,13 +722,12 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (unlikely(!net_eq(dev_net(dev), &init_net)))
 		goto drop;
 
-	if (WARN_ONCE(dev->type != ARPHRD_CAN ||
-		      skb->len != CAN_MTU ||
-		      cfd->len > CAN_MAX_DLEN,
-		      "PF_CAN: dropped non conform CAN skbuf: "
-		      "dev type %d, len %d, datalen %d\n",
-		      dev->type, skb->len, cfd->len))
+	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU ||
+		     cfd->len > CAN_MAX_DLEN)) {
+		pr_warn_once("PF_CAN: dropped non conform CAN skbuf: dev type %d, len %d, datalen %d\n",
+			     dev->type, skb->len, cfd->len);
 		goto drop;
+	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;
-- 
2.15.1

[PATCH 2/2] [stable pre-4.12] can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once

[Oliver Hartkopp]

In Linux 4.12 commit 8e8cda6d737d356054c ("can: initial support for network
namespaces") removed a namespace check which affected this patch:

can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once

upstream commit d4689846881d160a4d12a514e991a740bcb5d65a

If an invalid CANFD frame is received, from a driver or from a tun
interface, a Kernel warning is generated.

This patch replaces the WARN_ONCE by a simple pr_warn_once, so that a
kernel, bootet with panic_on_warn, does not panic. A printk seems to be
more appropriate here.

Reported-by: syzbot+e3b775f40babeff6e68b@syzkaller.appspotmail.com
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org> [pre 4.12]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/af_can.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 924ad0513af9..c866e761651a 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -745,13 +745,12 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (unlikely(!net_eq(dev_net(dev), &init_net)))
 		goto drop;
 
-	if (WARN_ONCE(dev->type != ARPHRD_CAN ||
-		      skb->len != CANFD_MTU ||
-		      cfd->len > CANFD_MAX_DLEN,
-		      "PF_CAN: dropped non conform CAN FD skbuf: "
-		      "dev type %d, len %d, datalen %d\n",
-		      dev->type, skb->len, cfd->len))
+	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU ||
+		     cfd->len > CANFD_MAX_DLEN)) {
+		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuf: dev type %d, len %d, datalen %d\n",
+			     dev->type, skb->len, cfd->len);
 		goto drop;
+	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;
-- 
2.15.1

Re: [PATCH 2/2] [stable pre-4.12] can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once

[Greg KH]

On Mon, Jan 22, 2018 at 02:44:47PM +0100, Oliver Hartkopp wrote:
> In Linux 4.12 commit 8e8cda6d737d356054c ("can: initial support for network
> namespaces") removed a namespace check which affected this patch:

Thanks for the two backports, now queued up.

greg k-h