ipv6: Fix ipv6_getsockopt for IPV6_2292PKTOPTIONS

IPV6_2292PKTOPTIONS is broken for 32-bit applications running
in COMPAT mode on 64-bit kernels.

The same problem was fixed for IPv4 with the patch:
ipv4: Fix ip_getsockopt for IP_PKTOPTIONS,
commit dd23198e58cd35259dd09e8892bbdb90f1d57748

Signed-off-by: Sorin Dumitru <[e-mail]>
Signed-off-by: Daniel Baluta <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv6/ipv6_sockglue.c

···
 }
 
 static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
-		    char __user *optval, int __user *optlen)
+		    char __user *optval, int __user *optlen, unsigned flags)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	int len;
···
 
 		msg.msg_control = optval;
 		msg.msg_controllen = len;
-		msg.msg_flags = 0;
+		msg.msg_flags = flags;
 
 		lock_sock(sk);
 		skb = np->pktoptions;
···
 	if(level != SOL_IPV6)
 		return -ENOPROTOOPT;
 
-	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen);
+	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen, 0);
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */
 	if (err == -ENOPROTOOPT && optname != IPV6_2292PKTOPTIONS) {
···
 		return compat_mc_getsockopt(sk, level, optname, optval, optlen,
 			ipv6_getsockopt);
 
-	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen);
+	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen,
+				 MSG_CMSG_COMPAT);
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */
 	if (err == -ENOPROTOOPT && optname != IPV6_2292PKTOPTIONS) {