[PATCH][next] can: etas_es58x: Fix potential null pointer dereference on pointer cf

[PATCH][next] can: etas_es58x: Fix potential null pointer dereference on pointer cf

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

The pointer cf is being null checked earlier in the code, however the
update of the rx_bytes statistics is dereferencing cf without null
checking cf.  Fix this by moving the statement into the following code
block that has a null cf check.

Addresses-Coverity: ("Dereference after null check")
Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/can/usb/etas_es58x/es58x_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
index 7222b3b6ca46..5198e1d6b6ad 100644
--- a/drivers/net/can/usb/etas_es58x/es58x_core.c
+++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
@@ -856,9 +856,10 @@ int es58x_rx_err_msg(struct net_device *netdev, enum es58x_err error,
 	 * consistency.
 	 */
 	netdev->stats.rx_packets++;
-	netdev->stats.rx_bytes += cf->can_dlc;
 
 	if (cf) {
+		netdev->stats.rx_bytes += cf->can_dlc;
+
 		if (cf->data[1])
 			cf->can_id |= CAN_ERR_CRTL;
 		if (cf->data[2] || cf->data[3]) {
-- 
2.30.2

Re: [PATCH][next] can: etas_es58x: Fix potential null pointer dereference on pointer cf

[Marc Kleine-Budde]

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On 15.04.2021 09:55:35, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The pointer cf is being null checked earlier in the code, however the
> update of the rx_bytes statistics is dereferencing cf without null
> checking cf.  Fix this by moving the statement into the following code
> block that has a null cf check.
> 
> Addresses-Coverity: ("Dereference after null check")
> Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

A somewhat different fix is already in net-next/master

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=e2b1e4b532abdd39bfb7313146153815e370d60c

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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Re: [PATCH][next] can: etas_es58x: Fix potential null pointer dereference on pointer cf

[Colin Ian King]

On 15/04/2021 10:03, Marc Kleine-Budde wrote:
> On 15.04.2021 09:55:35, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The pointer cf is being null checked earlier in the code, however the
>> update of the rx_bytes statistics is dereferencing cf without null
>> checking cf.  Fix this by moving the statement into the following code
>> block that has a null cf check.
>>
>> Addresses-Coverity: ("Dereference after null check")
>> Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> A somewhat different fix is already in net-next/master
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=e2b1e4b532abdd39bfb7313146153815e370d60c

+1 on that

> 
> Marc
>