[patch 2/2] staging: r8188eu: overflow in rtw_p2p_get_go_device_address()

Dan Carpenter
2014-02-03T22:38:35Z

The go_devadd_str[] array is two characters too small to hold the
address so we corrupt memory.

I've changed the user space API slightly and I don't have a way to test
if this breaks anything. In the original code we truncated away the
last digit of the address and the NUL terminator so it was already a bit
broken.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
index dec992569476..4ad80ae1067f 100644
--- a/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8188eu/os_dep/ioctl_linux.c
@@ -3164,9 +3164,7 @@ static int rtw_p2p_get_go_device_address(struct net_device *dev,
u8 *p2pie;
uint p2pielen = 0, attr_contentlen = 0;
u8 attr_content[100] = {0x00};
-
- u8 go_devadd_str[17 + 10] = {0x00};
- /* +10 is for the str "go_devadd =", we have to clear it at wrqu->data.pointer */
+ u8 go_devadd_str[17 + 12] = {};

/* Commented by Albert 20121209 */
/* The input data is the GO's interface address which the application wants to know its device address. */
@@ -3223,12 +3221,12 @@ static int rtw_p2p_get_go_device_address(struct net_device *dev,
spin_unlock_bh(&pmlmepriv->scanned_queue.lock);

if (!blnMatch)
- sprintf(go_devadd_str, "\n\ndev_add = NULL");
+ snprintf(go_devadd_str, sizeof(go_devadd_str), "\n\ndev_add = NULL");
else
- sprintf(go_devadd_str, "\n\ndev_add =%.2X:%.2X:%.2X:%.2X:%.2X:%.2X",
+ snprintf(go_devadd_str, sizeof(go_devadd_str), "\n\ndev_add =%.2X:%.2X:%.2X:%.2X:%.2X:%.2X",
attr_content[0], attr_content[1], attr_content[2], attr_content[3], attr_content[4], attr_content[5]);

- if (copy_to_user(wrqu->data.pointer, go_devadd_str, 10 + 17))
+ if (copy_to_user(wrqu->data.pointer, go_devadd_str, sizeof(go_devadd_str)))
return -EFAULT;
return ret;
}