[PATCH 4.9 010/108] ipv6: Handle IPv4-mapped src to in6addr_any dst.

Greg Kroah-Hartman
2017-06-15T17:57:03Z

From: "Jonathan T. Leighton" <jtleight@udel.edu>

[ Upstream commit 052d2369d1b479cdbbe020fdd6d057d3c342db74 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/datagram.c | 14 +++++++++-----
net/ipv6/tcp_ipv6.c | 11 ++++++++---
net/ipv6/udp.c | 4 ++++
3 files changed, 21 insertions(+), 8 deletions(-)

--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -166,18 +166,22 @@ int __ip6_datagram_connect(struct sock *
if (np->sndflow)
fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;

- addr_type = ipv6_addr_type(&usin->sin6_addr);
-
- if (addr_type == IPV6_ADDR_ANY) {
+ if (ipv6_addr_any(&usin->sin6_addr)) {
/*
* connect to self
*/
- usin->sin6_addr.s6_addr[15] = 0x01;
+ 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);
+
daddr = &usin->sin6_addr;

- if (addr_type == IPV6_ADDR_MAPPED) {
+ if (addr_type & IPV6_ADDR_MAPPED) {
struct sockaddr_in sin;

if (__ipv6_only_sock(sk)) {
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -148,8 +148,13 @@ static int tcp_v6_connect(struct sock *s
* 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 *s
* 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;

--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1049,6 +1049,10 @@ int udpv6_sendmsg(struct sock *sk, struc
if (addr_len < SIN6_LEN_RFC2133)
return -EINVAL;
daddr = &sin6->sin6_addr;
+ if (ipv6_addr_any(daddr) &&
+ ipv6_addr_v4mapped(&np->saddr))
+ ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
+ daddr);
break;
case AF_INET:
goto do_udp_sendmsg;