This is a note to let you know that I've just added the patch titled ipv6: Handle IPv4-mapped src to in6addr_any dst. to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv6-handle-ipv4-mapped-src-to-in6addr_any-dst.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Jun 15 09:31:48 CEST 2017 From: "Jonathan T. Leighton" <jtleight@xxxxxxxx> Date: Tue, 23 May 2017 21:53:33 -0400 Subject: ipv6: Handle IPv4-mapped src to in6addr_any dst. From: "Jonathan T. Leighton" <jtleight@xxxxxxxx> [ 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@xxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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; Patches currently in stable-queue which might be from jtleight@xxxxxxxx are queue-4.9/ipv6-inhibit-ipv4-mapped-src-address-on-the-wire.patch queue-4.9/ipv6-handle-ipv4-mapped-src-to-in6addr_any-dst.patch