[PATCHv2 net] ipv6: sr: fix invalid unregister error path

[Hangbin Liu <liuhangbin@gmail.com>]

The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL
is not defined. In that case if seg6_hmac_init() fails, the
genl_unregister_family() isn't called.

At the same time, add seg6_local_exit() and fix the genl unregister order
in seg6_exit().

Fixes: 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref")
Reported-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
v2: define label out_unregister_genl in CONFIG_IPV6_SEG6_LWTUNNEL(Sabrina Dubroca)
---
 net/ipv6/seg6.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/seg6.c b/net/ipv6/seg6.c
index 35508abd76f4..6a80d93399ce 100644
--- a/net/ipv6/seg6.c
+++ b/net/ipv6/seg6.c
@@ -551,8 +551,8 @@ int __init seg6_init(void)
 #endif
 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 out_unregister_genl:
-	genl_unregister_family(&seg6_genl_family);
 #endif
+	genl_unregister_family(&seg6_genl_family);
 out_unregister_pernet:
 	unregister_pernet_subsys(&ip6_segments_ops);
 	goto out;
@@ -564,8 +564,9 @@ void seg6_exit(void)
 	seg6_hmac_exit();
 #endif
 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
+	seg6_local_exit();
 	seg6_iptunnel_exit();
 #endif
-	unregister_pernet_subsys(&ip6_segments_ops);
 	genl_unregister_family(&seg6_genl_family);
+	unregister_pernet_subsys(&ip6_segments_ops);
 }
-- 
2.43.0