airo: airo_get_encode{,ext} potential buffer overflow

Feeding the return code of get_wep_key directly to the length parameter
of memcpy is a bad idea since it could be -1...

Reported-by: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c
index c36d3a3..d734757 100644 (file)
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -6501,7 +6501,10 @@ static int airo_get_encode(struct net_device *dev,
 
        /* Copy the key to the user buffer */
        dwrq->length = get_wep_key(local, index, &buf[0], sizeof(buf));
-       memcpy(extra, buf, dwrq->length);
+       if (dwrq->length != -1)
+               memcpy(extra, buf, dwrq->length);
+       else
+               dwrq->length = 0;
 
        return 0;
 }
@@ -6659,7 +6662,10 @@ static int airo_get_encodeext(struct net_device *dev,
        
        /* Copy the key to the user buffer */
        ext->key_len = get_wep_key(local, idx, &buf[0], sizeof(buf));
-       memcpy(extra, buf, ext->key_len);
+       if (ext->key_len != -1)
+               memcpy(extra, buf, ext->key_len);
+       else
+               ext->key_len = 0;
 
        return 0;
 }