On Sun, Apr 03, 2022 at 10:52:07PM -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. > > 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..4b4eec2bde96 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) > + return 0; return -EFAULT; We can't assume that that user wants to copy 9 bytes especially when they're passing a 4 character + NUL string. This is a custom ioctl. Called from ioctl_private_iw_point(). I think if you try to dereference a user pointer like this then it will cause a crash, right? So that means no one has ever tested or used this code and we hopefully we can just delete it? regards, dan carpenter