staging: rtl8712: unterminated string leads to read overflow

The memdup_user() function does not necessarily return a NUL terminated
string so this can lead to a read overflow.  Switch from memdup_user()
to strndup_user() to fix this bug.

Fixes: c6dc001f2add ("staging: r8712u: Merging Realtek's latest (v2.6.6). Various fixes.")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YDYSR+1rj26NRhvb@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c
index 81de5a9..60dd798 100644 (file)
--- a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c
+++ b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c
@@ -924,7 +924,7 @@ static int r871x_wx_set_priv(struct net_device *dev,
        struct iw_point *dwrq = (struct iw_point *)awrq;
 
        len = dwrq->length;
-       ext = memdup_user(dwrq->pointer, len);
+       ext = strndup_user(dwrq->pointer, len);
        if (IS_ERR(ext))
                return PTR_ERR(ext);