[PATCH 4.17 03/15] ip6mr: only set ip6mr_table from setsockopt when ip6mr_new_table succeeds

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sabrina Dubroca <sd@queasysnail.net>

[ Upstream commit 848235edb5c93ed086700584c8ff64f6d7fc778d ]

Currently, raw6_sk(sk)->ip6mr_table is set unconditionally during
ip6_mroute_setsockopt(MRT6_TABLE). A subsequent attempt at the same
setsockopt will fail with -ENOENT, since we haven't actually created
that table.

A similar fix for ipv4 was included in commit 5e1859fbcc3c ("ipv4: ipmr:
various fixes and cleanups").

Fixes: d1db275dd3f6 ("ipv6: ip6mr: support multiple tables")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/ip6mr.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1759,7 +1759,8 @@ int ip6_mroute_setsockopt(struct sock *s
 		ret = 0;
 		if (!ip6mr_new_table(net, v))
 			ret = -ENOMEM;
-		raw6_sk(sk)->ip6mr_table = v;
+		else
+			raw6_sk(sk)->ip6mr_table = v;
 		rtnl_unlock();
 		return ret;
 	}