Smack: IPv6 casting error fix for 3.11

The original implementation of the Smack IPv6 port based
local controls works most of the time using a sockaddr as
a temporary variable, but not always as it overflows in
some circumstances. The correct data is a sockaddr_in6.
A struct sockaddr isn't as large as a struct sockaddr_in6.
There would need to be casting one way or the other. This
patch gets it the right way.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

security/smack/smack_lsm.c

@@ -1998,12 +1998,11 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
  *
  * Create or update the port list entry
  */
-static int smk_ipv6_port_check(struct sock *sk, struct sockaddr *address,
+static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 				int act)
 {
 	__be16 *bep;
 	__be32 *be32p;
-	struct sockaddr_in6 *addr6;
 	struct smk_port_label *spp;
 	struct socket_smack *ssp = sk->sk_security;
 	struct smack_known *skp;
@@ -2025,10 +2024,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr *address,
 	/*
 	 * Get the IP address and port from the address.
 	 */
-	addr6 = (struct sockaddr_in6 *)address;
-	port = ntohs(addr6->sin6_port);
-	bep = (__be16 *)(&addr6->sin6_addr);
-	be32p = (__be32 *)(&addr6->sin6_addr);
+	port = ntohs(address->sin6_port);
+	bep = (__be16 *)(&address->sin6_addr);
+	be32p = (__be32 *)(&address->sin6_addr);
 
 	/*
 	 * It's remote, so port lookup does no good.
@@ -2060,9 +2058,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr *address,
 	ad.a.u.net->family = sk->sk_family;
 	ad.a.u.net->dport = port;
 	if (act == SMK_RECEIVING)
-		ad.a.u.net->v6info.saddr = addr6->sin6_addr;
+		ad.a.u.net->v6info.saddr = address->sin6_addr;
 	else
-		ad.a.u.net->v6info.daddr = addr6->sin6_addr;
+		ad.a.u.net->v6info.daddr = address->sin6_addr;
 #endif
 	return smk_access(skp, object, MAY_WRITE, &ad);
 }
@@ -2201,7 +2199,8 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
 	case PF_INET6:
 		if (addrlen < sizeof(struct sockaddr_in6))
 			return -EINVAL;
-		rc = smk_ipv6_port_check(sock->sk, sap, SMK_CONNECTING);
+		rc = smk_ipv6_port_check(sock->sk, (struct sockaddr_in6 *)sap,
+						SMK_CONNECTING);
 		break;
 	}
 	return rc;
@@ -3034,7 +3033,7 @@ static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
 				int size)
 {
 	struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
-	struct sockaddr *sap = (struct sockaddr *) msg->msg_name;
+	struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
 	int rc = 0;
 
 	/*
@@ -3121,9 +3120,8 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 	return smack_net_ambient;
 }
 
-static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr *sap)
+static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
 {
-	struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
 	u8 nexthdr;
 	int offset;
 	int proto = -EINVAL;
@@ -3181,7 +3179,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	struct netlbl_lsm_secattr secattr;
 	struct socket_smack *ssp = sk->sk_security;
 	struct smack_known *skp;
-	struct sockaddr sadd;
+	struct sockaddr_in6 sadd;
 	int rc = 0;
 	struct smk_audit_info ad;
 #ifdef CONFIG_AUDIT