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H A Daf_inet6.cafe49de4 Tue Aug 28 06:40:51 CDT 2018 Sabrina Dubroca <sd@queasysnail.net> ipv6: fix cleanup ordering for ip6_mr failure

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>
afe49de4 Tue Aug 28 06:40:51 CDT 2018 Sabrina Dubroca <sd@queasysnail.net> ipv6: fix cleanup ordering for ip6_mr failure

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>