On Wed, Apr 06, 2022 at 07:25:42AM -0400, Charlie Sands wrote:
> This patch fixes sparse warnings about the memcmp function unsafely accessing
> userspace memory without first copying it to kernel space.
>
> Signed-off-by: Charlie Sands <sandsch@xxxxxxxxxxxxxxxxxxxxx>
> ---
>
> V2: Fixed checkpatch.pl warning and changed variable name as suggested by Greg
> K. H. and improved error checking on the "copy_from_user" function as suggested
> by Pavel Skripkin.
>
> V3: return -EFAULT from the function when there is a memory error while moving
> it from user space to kernel space and fix incorrect subject from V2
>
> drivers/staging/r8188eu/os_dep/ioctl_linux.c | 21 ++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> index 7df213856d66..9f2182b8e451 100644
> --- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> +++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> @@ -3233,23 +3233,28 @@ static int rtw_p2p_get(struct net_device *dev,
> struct iw_request_info *info,
> union iwreq_data *wrqu, char *extra)
> {
> - if (!memcmp(wrqu->data.pointer, "status", 6)) {
> + char wrqu_data[9];
> +
> + if (copy_from_user(wrqu_data, wrqu->data.pointer, 9) != 0)
How do you know that the user buffer is passing 9 characters long?
You're fixing a real bug, sure, but you've inventing a new API and it's
a rubbish API. Just delete rtw_p2p_get() and the associated code. It
has never worked so no one will miss it.
regards,
dan carpenter
