[lvc-project] [PATCH ipsec] xfrm: fix refcount leak in xfrm_migrate_policy_find

[Florian Westphal]

Kotlyarov Mihail <mihailkotlyarow at gmail.com> wrote:
> syzkaller reported a memory leak in xfrm_policy_alloc:
> 
>   BUG: memory leak
>   unreferenced object 0xffff888114d79000 (size 1024):
>     comm "syz.1.17", pid 931
>     ...
>     xfrm_policy_alloc+0xb3/0x4b0 net/xfrm/xfrm_policy.c:432
> 
> The root cause is a double call to xfrm_pol_hold_rcu() in
> xfrm_migrate_policy_find(). The lookup function already returns
> a policy with held reference, making the second call redundant.
> Remove the redundant xfrm_pol_hold_rcu() call to fix the refcount
> imbalance and prevent the memory leak.

Reviewed-by: Florian Westphal <fw at strlen.de>