ipv6: fix cleanup ordering for ip6_mr failure

Commit db84b82bdef5 ("ipv6: reorder icmpv6_init() and ip6_mr_init()")
moved the cleanup label for ipmr_fail, but should have changed the
contents of the cleanup labels as well. Now we can end up cleaning up
icmpv6 even though it hasn't been initialized (jump to icmp_fail or
ipmr_fail).

Simply undo things in the reverse order of their initialization.

Example of panic (triggered by faking a failure of icmpv6_init):

    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
    [...]
    RIP: 0010:__list_del_entry_valid+0x79/0x160
    [...]
    Call Trace:
     ? lock_release+0x8a0/0x8a0
     unregister_pernet_operations+0xd4/0x560
     ? ops_free_list+0x480/0x480
     ? down_write+0x91/0x130
     ? unregister_pernet_subsys+0x15/0x30
     ? down_read+0x1b0/0x1b0
     ? up_read+0x110/0x110
     ? kmem_cache_create_usercopy+0x1b4/0x240
     unregister_pernet_subsys+0x1d/0x30
     icmpv6_cleanup+0x1d/0x30
     inet6_init+0x1b5/0x23f

Fixes: db84b82bdef5 ("ipv6: reorder icmpv6_init() and ip6_mr_init()")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 673bba31eb1807eb04ee0d0c072333000bde4305..e5da133c6932f3e427a6aa893ab271bb51c1aefa 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -1113,11 +1113,11 @@ netfilter_fail:
 igmp_fail:
        ndisc_cleanup();
 ndisc_fail:
-       ip6_mr_cleanup();
+       icmpv6_cleanup();
 icmp_fail:
-       unregister_pernet_subsys(&inet6_net_ops);
+       ip6_mr_cleanup();
 ipmr_fail:
-       icmpv6_cleanup();
+       unregister_pernet_subsys(&inet6_net_ops);
 register_pernet_fail:
        sock_unregister(PF_INET6);
        rtnl_unregister_all(PF_INET6);