batman-adv: Only write requested number of byte to user buffer
authorSven Eckelmann <sven@narfation.org>
Sat, 10 Dec 2011 14:28:36 +0000 (15:28 +0100)
committerMarek Lindner <lindner_marek@yahoo.de>
Mon, 12 Dec 2011 11:11:07 +0000 (19:11 +0800)
Don't write more than the requested number of bytes of an batman-adv icmp
packet to the userspace buffer. Otherwise unrelated userspace memory might get
overridden by the kernel.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
net/batman-adv/icmp_socket.c

index 3b04fff..d9c1e7b 100644 (file)
@@ -136,10 +136,9 @@ static ssize_t bat_socket_read(struct file *file, char __user *buf,
 
        spin_unlock_bh(&socket_client->lock);
 
-       error = copy_to_user(buf, &socket_packet->icmp_packet,
-                            socket_packet->icmp_len);
+       packet_len = min(count, socket_packet->icmp_len);
+       error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 
-       packet_len = socket_packet->icmp_len;
        kfree(socket_packet);
 
        if (error)