[RFC 0/2] ima: evm: Add kernel cmdline options to disable IMA/EVM

[Song Liu]

> On Dec 17, 2024, at 3:33 PM, Song Liu <songliubraving at meta.com> wrote:

[...]

> 
>>> +
>>>                               found = true;
>>>                       }
>>>               }
>>> @@ -386,7 +389,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
>>> 
>>>       /* LSM_ORDER_LAST is always last. */
>>>       for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
>>> -               if (lsm->order == LSM_ORDER_LAST)
>>> +               if (lsm->order == LSM_ORDER_LAST && is_enabled(lsm))
>>>                       append_ordered_lsm(lsm, "   last");
> 
> Before this change, lsm with order==LSM_ORDER_LAST is always considered
> enabled, which is a bug (if I understand you and Casey correctly).

According to commit 42994ee3cd7298b27698daa6848ed7168e72d056, LSMs with 
order LSM_ORDER_LAST is expected to be always enabled:

"Similarly to LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled
and put at the end of the LSM list, if selected in the kernel
configuration. "

Roberto, it feels weird to have two "last and always on" LSMs (ima and evm)
I guess this is not the expected behavior? At least, it appears to be a
surprise for Paul and Casey. 

I will send patch that allow enable/disable ima and evm with lsm= cmdline.
We can further discuss the topic with the patch. 

Thanks,
Song