The insertion can cause the existing data to get reallocated/moved. So
if the caller attempts to insert another copy of an existing element into
the array via its pointer, this can cause a undefined behavior or even
a use-after-free because the pointer might get invalid.
There is such a case in `mem_pool_t::get_existing()` since the referenced
commit.
Fixes: d4a0dd9f93 ("mem-pool: Fix issue with make-before-break reauth and multiple IKE_SAs")
Tobias Brunner
588c7a80d1