ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy

BugLink: http://bugs.launchpad.net/bugs/1768474

[ Upstream commit aa8f8778 ]

KMSAN reported use of uninit-value that I tracked to lack
of proper size check on RTA_TABLE attribute.

I also believe RTA_PREFSRC lacks a similar check.

Fixes: 86872cb5 ("[IPv6] route: FIB6 configuration using struct fib6_config")
Fixes: c3968a85 ("ipv6: RTA_PREFSRC support for ipv6 route source address selection")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/ipv6/route.c

@@ -2733,6 +2733,7 @@ void rt6_mtu_change(struct net_device *dev, unsigned int mtu)
 
 static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
 	[RTA_GATEWAY]           = { .len = sizeof(struct in6_addr) },
+	[RTA_PREFSRC]		= { .len = sizeof(struct in6_addr) },
 	[RTA_OIF]               = { .type = NLA_U32 },
 	[RTA_IIF]		= { .type = NLA_U32 },
 	[RTA_PRIORITY]          = { .type = NLA_U32 },
@@ -2741,6 +2742,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
 	[RTA_PREF]              = { .type = NLA_U8 },
 	[RTA_ENCAP_TYPE]	= { .type = NLA_U16 },
 	[RTA_ENCAP]		= { .type = NLA_NESTED },
+	[RTA_TABLE]		= { .type = NLA_U32 },
 };
 
 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,