[PATCH] gpib: agilent_82357a: don't check a NULL serial string

[PATCH] gpib: agilent_82357a: don't check a NULL serial string

[Joe Simmons-Talbott]

The agilent_82357a driver uses the USB device serial string for device
matching but does not verify that the string exists before passing it
to strcmp().

Verify that the device has a serial number before accessing it to avoid
triggering a NULL-pointer dereference with devices that don't provide
a serial number (iSerialNumber = 0).

Similar to commit aa79f996eb41 ("i2c: cp2615: fix serial string
NULL-deref at probe").

Found by Claude:sonnet-4.5

Signed-off-by: Joe Simmons-Talbott <joest@redhat.com>
---
 drivers/gpib/agilent_82357a/agilent_82357a.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpib/agilent_82357a/agilent_82357a.c b/drivers/gpib/agilent_82357a/agilent_82357a.c
index e1349afbf933..da046ea40f11 100644
--- a/drivers/gpib/agilent_82357a/agilent_82357a.c
+++ b/drivers/gpib/agilent_82357a/agilent_82357a.c
@@ -1298,7 +1298,7 @@ static inline int agilent_82357a_device_match(struct usb_interface *interface,
 	if (gpib_match_device_path(&interface->dev, config->device_path) == 0)
 		return 0;
 	if (config->serial_number &&
-	    strcmp(usbdev->serial, config->serial_number) != 0)
+	    (!usbdev->serial || strcmp(usbdev->serial, config->serial_number) != 0))
 		return 0;
 
 	return 1;
-- 
2.53.0

Re: [PATCH] gpib: agilent_82357a: don't check a NULL serial string

[Dave Penkler]

On Thu, Mar 26, 2026 at 09:12:56AM -0400, Joe Simmons-Talbott wrote:
> The agilent_82357a driver uses the USB device serial string for device
> matching but does not verify that the string exists before passing it
> to strcmp().
> 
> Verify that the device has a serial number before accessing it to avoid
> triggering a NULL-pointer dereference with devices that don't provide
> a serial number (iSerialNumber = 0).
> 
> Similar to commit aa79f996eb41 ("i2c: cp2615: fix serial string
> NULL-deref at probe").
> 
> Found by Claude:sonnet-4.5
> 
> Signed-off-by: Joe Simmons-Talbott <joest@redhat.com>
> ---
>  drivers/gpib/agilent_82357a/agilent_82357a.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpib/agilent_82357a/agilent_82357a.c b/drivers/gpib/agilent_82357a/agilent_82357a.c
> index e1349afbf933..da046ea40f11 100644
> --- a/drivers/gpib/agilent_82357a/agilent_82357a.c
> +++ b/drivers/gpib/agilent_82357a/agilent_82357a.c
> @@ -1298,7 +1298,7 @@ static inline int agilent_82357a_device_match(struct usb_interface *interface,
>  	if (gpib_match_device_path(&interface->dev, config->device_path) == 0)
>  		return 0;
>  	if (config->serial_number &&
> -	    strcmp(usbdev->serial, config->serial_number) != 0)
> +	    (!usbdev->serial || strcmp(usbdev->serial, config->serial_number) != 0))
>  		return 0;
>  
>  	return 1;
> -- 
> 2.53.0
> 
Acked-by: Dave Penkler <dpenkler@gmail.com>