staging: rtl8188eu: Fix potential overuse of kernel memory

commit 4ddf8ab8d15ddbc52eefb44eb64e38466ce1f70f upstream.

In routine wpa_supplicant_ioctl(), the user-controlled p->length is
checked to be at least the size of struct ieee_param size, but the code
does not detect the case where p->length is greater than the size
of the struct, thus a malicious user could be wasting kernel memory.
Fixes commit a2c60d42d97c ("Add files for new driver - part 16").

Reported by: Pietro Oliva <pietroliva@gmail.com>
Cc: Pietro Oliva <pietroliva@gmail.com>
Cc: Stable <stable@vger.kernel.org>
Fixes commit a2c60d42d97c ("Add files for new driver - part 16").
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Link: https://lore.kernel.org/r/20200210180235.21691-4-Larry.Finger@lwfinger.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
index a8bd13c..0003f0c 100644 (file)
--- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
@@ -2026,7 +2026,7 @@ static int wpa_supplicant_ioctl(struct net_device *dev, struct iw_point *p)
        struct ieee_param *param;
        uint ret = 0;
 
-       if (p->length < sizeof(struct ieee_param) || !p->pointer) {
+       if (!p->pointer || p->length != sizeof(struct ieee_param)) {
                ret = -EINVAL;
                goto out;
        }