On Tue, Oct 27, 2020 at 6:31 PM Akinobu Mita [off-list ref] wrote:

[...]

In addition to this global one, what do you think about per-hook fault
injection,
i.e. /sys/kernel/debug/fail_lsm_hooks/<FUNC>/retval ?

I was thinking about this, but decided to begin with a simple version
that could definitely be useful in practice (for syzbot/syzkaller it is just
necessary to have a fault injection capability that will be triggered via
fail-nth). If per-hook fault injection can also be useful to someone, I
can try to add it as well.

In this case, we need a fault_attr for each hook. (Maybe, we can use the same
technique that is used to define security_hook_heads).

Yes, that technique should help to implement the feature in a very concise
way. Thanks for the suggestion.