[PATCH] kernel-device: avoid potential NULL dereference

[Aleksander Morgado]

On 12/08/17 09:08, Ben Chan wrote:
> The patch fixes get_device_ids() in mm-kernel-device-udev.c to avoid
> potential NULL dereferences of the 'vendor' argument. It also rearranges
> the code such that the 'vendor' argument is updated only when the
> function returns TRUE, just like how the 'product' argument is handled.
> ---

Looks like this method is only used in a single place, and vendor and product are always defined (never NULL). How about removing the if (vendor) and if (product) checks? I agree with the reorder, though.


>  src/kerneldevice/mm-kernel-device-udev.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/src/kerneldevice/mm-kernel-device-udev.c b/src/kerneldevice/mm-kernel-device-udev.c
> index e8763f7e..e2c2bf34 100644
> --- a/src/kerneldevice/mm-kernel-device-udev.c
> +++ b/src/kerneldevice/mm-kernel-device-udev.c
> @@ -119,23 +119,19 @@ get_device_ids (GUdevDevice *device,
>      if (strlen (vid) != 4)
>          goto out;
>  
> -    if (vendor) {
> -        *vendor = (guint16) (mm_utils_hex2byte (vid + 2) & 0xFF);
> -        *vendor |= (guint16) ((mm_utils_hex2byte (vid) & 0xFF) << 8);
> -    }
> -
>      if (!pid)
>          pid = g_udev_device_get_property (device, "ID_MODEL_ID");
> -    if (!pid) {
> -        *vendor = 0;
> +    if (!pid)
>          goto out;
> -    }
>  
>      if (strncmp (pid, "0x", 2) == 0)
>          pid += 2;
> -    if (strlen (pid) != 4) {
> -        *vendor = 0;
> +    if (strlen (pid) != 4)
>          goto out;
> +
> +    if (vendor) {
> +        *vendor = (guint16) (mm_utils_hex2byte (vid + 2) & 0xFF);
> +        *vendor |= (guint16) ((mm_utils_hex2byte (vid) & 0xFF) << 8);
>      }
>  
>      if (product) {
> 


-- 
Aleksander
https://aleksander.es