4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit afe49de44c27a89e8e9631c44b5ffadf6ace65e2 ]
Commit 15e668070a64 ("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: 15e668070a64 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/af_inet6.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 421379014995..f7b425615c12 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -1045,11 +1045,11 @@ 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);