ipv6: check for IPv4 mapped addresses when connecting IPv6 sockets

When support for binding to 'mapped INADDR_ANY (::ffff.0.0.0.0)' was added
in 5d800c11299a67405192a34e7a46e67d3808fb41 the rest of the code
wasn't told so now it's possible to bind IPv6 datagram socket to
::ffff.0.0.0.0, connect it to another IPv4 address and it will all
work except for getsockhame() which does not return the local address
as expected.

To give getsockname() something to work with check for 'mapped INADDR_ANY'
when connecting and update the in-core source addresses appropriately.

Signed-off-by: Max Matveev <makc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 16560336eb72315c9abb6e3938b6c01af3f3aa1f..9ef1831746efb70a1776791279e3c263f0be18d0 100644 (file)
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -33,6 +33,11 @@
 #include <linux/errqueue.h>
 #include <asm/uaccess.h>
 
+static inline int ipv6_mapped_addr_any(const struct in6_addr *a)
+{
+       return (ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0));
+}
+
 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 {
        struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
@@ -102,10 +107,12 @@ ipv4_connected:
 
                ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
 
-               if (ipv6_addr_any(&np->saddr))
+               if (ipv6_addr_any(&np->saddr) ||
+                   ipv6_mapped_addr_any(&np->saddr))
                        ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 
-               if (ipv6_addr_any(&np->rcv_saddr)) {
+               if (ipv6_addr_any(&np->rcv_saddr) ||
+                   ipv6_mapped_addr_any(&np->rcv_saddr)) {
                        ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
                                               &np->rcv_saddr);
                        if (sk->sk_prot->rehash)