On Tue, Oct 27, 2020 at 6:34 PM Aleksandr Nogikh <[email protected]> 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.
Yes, before we add it, it would be useful to have a clear use case (otherwise we can add an unused thing, or implement it in a way that slightly misses the use case). Note that fail-nth allows to fail a single concrete site for testing, though it's not super convenient for this as one would need to figure out the right N first. But as a one-off test it should do. > > 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.
