CAN: Use inode instead of kernel address for /proc file

commit 9f260e0e upstream.

Since the socket address is just being used as a unique identifier, its
inode number is an alternative that does not leak potentially sensitive
information.

CC-ing stable because MITRE has assigned CVE-2010-4565 to the issue.
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Moritz Muehlenhoff <jmm@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/can/bcm.c

@@ -124,7 +124,7 @@ struct bcm_sock {
 	struct list_head tx_ops;
 	unsigned long dropped_usr_msgs;
 	struct proc_dir_entry *bcm_proc_read;
-	char procname [20]; /* pointer printed in ASCII with \0 */
+	char procname [32]; /* inode number in decimal with \0 */
 };
 
 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
@@ -1519,7 +1519,7 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
 
 	if (proc_dir) {
 		/* unique socket address as filename */
-		sprintf(bo->procname, "%p", sock);
+		sprintf(bo->procname, "%lu", sock_i_ino(sk));
 		bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
 						     proc_dir,
 						     &bcm_proc_fops, sk);