Commit 144adc65 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'ipv6-v4mapped' 



Jonathan T. Leighton says:

====================
IPv4-mapped on wire, :: dst address issue

Under some circumstances IPv6 datagrams are sent with IPv4-mapped IPv6
addresses as the source. Given an IPv6 socket bound to an IPv4-mapped
IPv6 address, and an IPv6 destination address, both TCP and UDP will
will send packets using the IPv4-mapped IPv6 address as the source. Per
RFC 6890 (Table 20), IPv4-mapped IPv6 source addresses are not allowed
in an IP datagram. The problem can be observed by attempting to
connect() either a TCP or UDP socket, or by using sendmsg() with a UDP
socket. The patch is intended to correct this issue for all socket
types.

linux follows the BSD convention that an IPv6 destination address
specified as in6addr_any is converted to the loopback address.
Currently, neither TCP nor UDP consider the possibility that the source
address is an IPv4-mapped IPv6 address, and assume that the appropriate
loopback address is ::1. The patch adds a check on whether or not the
source address is an IPv4-mapped IPv6 address and then sets the
destination address to either ::ffff:127.0.0.1 or ::1, as appropriate.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents fed06ee8 052d2369

net/ipv6/datagram.c

+9 −5
Original line number Diff line number Diff line
@@ -167,18 +167,22 @@ int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, 
	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)) {

net/ipv6/ip6_output.c

+3 −0
Original line number Diff line number Diff line
@@ -1021,6 +1021,9 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, 
		}

	}

#endif

	if (ipv6_addr_v4mapped(&fl6->saddr) &&

	    !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr)))

		return -EAFNOSUPPORT;



	return 0;

net/ipv6/tcp_ipv6.c

+8 −3
Original line number Diff line number Diff line
@@ -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;

net/ipv6/udp.c

+4 −0
Original line number Diff line number Diff line
@@ -1033,6 +1033,10 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
			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;

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