ipv6: Handle IPv4-mapped src to in6addr_any dst.

This patch adds a check on the type of the source address for the case
where the destination address is in6addr_any. If the source is an
IPv4-mapped IPv6 source address, the destination is changed to
::ffff:127.0.0.1, and otherwise the destination is changed to ::1. This
is done in three locations to handle UDP calls to either connect() or
sendmsg() and TCP calls to connect(). Note that udpv6_sendmsg() delays
handling an in6addr_any destination until very late, so the patch only
needs to handle the case where the source is an IPv4-mapped IPv6
address.

Signed-off-by: Jonathan T. Leighton <jtleight@udel.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 3 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index eaad72c3d746..4c60c6f71cd3 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -148,8 +148,13 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
          *      connect() to INADDR_ANY means loopback (BSD'ism).
          */
 
-        if (ipv6_addr_any(&usin->sin6_addr))
-                usin->sin6_addr.s6_addr[15] = 0x1;
+        if (ipv6_addr_any(&usin->sin6_addr)) {
+                if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
+                        ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
+                                               &usin->sin6_addr);
+                else
+                        usin->sin6_addr = in6addr_loopback;
+        }
 
         addr_type = ipv6_addr_type(&usin->sin6_addr);
 
@@ -188,7 +193,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
          *      TCP over IPv4
          */
 
-        if (addr_type == IPV6_ADDR_MAPPED) {
+        if (addr_type & IPV6_ADDR_MAPPED) {
                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
                 struct sockaddr_in sin;