[PATCH 4.14 188/237] staging: rtl8188eu: Fix potential overuse of kernel memory

[Greg Kroah-Hartman]

From: Larry Finger <Larry.Finger@xxxxxxxxxxxx>

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@xxxxxxxxx>
Cc: Pietro Oliva <pietroliva@xxxxxxxxx>
Cc: Stable <stable@xxxxxxxxxxxxxxx>
Fixes commit a2c60d42d97c ("Add files for new driver - part 16").
Signed-off-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200210180235.21691-4-Larry.Finger@xxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/staging/rtl8188eu/os_dep/ioctl_linux.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
@@ -2051,7 +2051,7 @@ static int wpa_supplicant_ioctl(struct n
 	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;
 	}