4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Jonathan T. Leighton" <jtleight@xxxxxxxx> [ Upstream commit ec5e3b0a1d41fbda0cc33a45bc9e54e91d9d12c7 ] This patch adds a check for the problematic case of an IPv4-mapped IPv6 source address and a destination address that is neither an IPv4-mapped IPv6 address nor in6addr_any, and returns an appropriate error. The check in done before returning from looking up the route. 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/ip6_output.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1019,6 +1019,9 @@ static int ip6_dst_lookup_tail(struct ne } } #endif + if (ipv6_addr_v4mapped(&fl6->saddr) && + !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) + return -EAFNOSUPPORT; return 0;