On Tue, 2020-08-25 at 12:35 -0700, Lakshmi Ramasubramanian wrote:
> On 8/25/20 11:03 AM, Mimi Zohar wrote:
> > On Tue, 2020-08-25 at 10:55 -0700, Lakshmi Ramasubramanian wrote:
> > > On 8/25/20 10:42 AM, Mimi Zohar wrote:
> > >
> > > > > > Please limit the changes in this patch to renaming the functions and/or
> > > > > > files. For example, adding "measure_payload_hash" should be a separate
> > > > > > patch, not hidden here.
> > > > > >
> > > > >
> > > > > Thanks for the feedback Mimi.
> > > > >
> > > > > I'll split this into 2 patches:
> > > > >
> > > > > PATCH 1: Rename files + rename CONFIG
> > > > > PATCH 2: Update IMA hook to utilize early boot data measurement.
> > > >
> > > > I'm referring to introducing the "measure_payload_hash" flag. I assume
> > > > this is to indicate whether the buffer should be hashed or not.
> > > >
> > > > Example 1: ima_alloc_key_entry() and ima_alloc_data_entry(0 comparison
> > > > > -static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring,
> > > > > - const void *payload,
> > > > > - size_t payload_len)
> > > > > -{
> > > > > +static struct ima_data_entry *ima_alloc_data_entry(const char *event_name,
> > > > > + const void *payload,
> > > > > + size_t payload_len,
> > > > > + const char *event_data,
> > > > > + enum ima_hooks func,
> > > > > + bool measure_payload_hash) <====
> > > > > +{
> > > >
> > > > Example 2:
> > > > diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c
> > > > index a74095793936..65423754765f 100644
> > > > --- a/security/integrity/ima/ima_asymmetric_keys.c
> > > > +++ b/security/integrity/ima/ima_asymmetric_keys.c
> > > > @@ -37,9 +37,10 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
> > > > if (!payload || (payload_len == 0))
> > > > return;
> > > >
> > > > - if (ima_should_queue_key())
> > > > - queued = ima_queue_key(keyring, payload, payload_len);
> > > > -
> > > > + if (ima_should_queue_data())
> > > > + queued = ima_queue_data(keyring->description, payload,
> > > > + payload_len, keyring->description,
> > > > + KEY_CHECK, false); <===
> > > > if (queued)
> > > > return;
> > > >
> > > > But in general, as much as possible function and file name changes
> > > > should be done independently of other changes.
> > > >
> > > > thanks,
> > >
> > > I agree - but in this case, Tushar's patch series on adding support for
> > > "Critical Data" measurement has already introduced
> > > "measure_payload_hash" flag. His patch updates
> > > "process_buffer_measurement()" to take this new flag and measure hash of
> > > the given data.
> > >
> > > My patches extend that to queuing the early boot requests and processing
> > > them after a custom IMA policy is loaded.
> > >
> > > If you still think "measure_payload_hash" flag should be introduced in
> > > the queuing change as a separate patch I'll split the patches further.
> > > Please let me know.
> >
> > There's a major problem if his changes add new function arguments
> > without modifying all the callers of the function. I assume the kernel
> > would fail to compile properly.
>
> Tushar's patch series does update all the existing callers of
> process_buffer_measurement() to handle the new arguments. His patch
> series is self contained, and builds and works fine.
Yes, he's added "false" to existing calls. Still, defining a new IMA
hook should be independent of adding this "measure_payload_hash"
parameter. Each with its own patch description.
>
> > Changing the function parameters to include "measure_payload_hash"
> > needs to be a separate patch, whether it is part of his patch set or
> > yours.
> >
>
> ok - I'll split the queuing patch to include "measure_payload_hash" in a
> separate patch.
thanks,
Mimi
