wext: Add bound checks for copy_from_user

The wireless extensions have a copy_from_user to a local stack
array "essid", but both me and gcc have failed to find where
the bounds for this copy are located in the code.

This patch adds some basic sanity checks for the copy length
to make sure that we don't overflow the stack buffer.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Arjan van de Ven 2009-09-26 20:51:14 +02:00 committed by John W. Linville
parent 0ff716136a
commit 8503bd8c7d

View File

@ -773,10 +773,13 @@ static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd,
essid_compat = 1;
else if (IW_IS_SET(cmd) && (iwp->length != 0)) {
char essid[IW_ESSID_MAX_SIZE + 1];
unsigned int len;
len = iwp->length * descr->token_size;
err = copy_from_user(essid, iwp->pointer,
iwp->length *
descr->token_size);
if (len > IW_ESSID_MAX_SIZE)
return -EFAULT;
err = copy_from_user(essid, iwp->pointer, len);
if (err)
return -EFAULT;