linux-kernel - Re: [PATCH v9 6/6] tpm: pass an array of tpm_extend_digest structures to tpm_pcr

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Message-Id: <1549285149.4146.56.camel@linux.ibm.com>
Date:   Mon, 04 Feb 2019 07:59:09 -0500
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Roberto Sassu <roberto.sassu@...wei.com>
Cc:     david.safford@...com, monty.wiseman@...com,
        matthewgarrett@...gle.com, linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org, silviu.vlasceanu@...wei.com
Subject: Re: [PATCH v9 6/6] tpm: pass an array of tpm_extend_digest
 structures to tpm_pcr_extend()

On Mon, 2019-02-04 at 14:07 +0200, Jarkko Sakkinen wrote:
> On Mon, Feb 04, 2019 at 10:14:38AM +0100, Roberto Sassu wrote:
> > On 2/1/2019 8:15 PM, Mimi Zohar wrote:
> > > Hi Roberto,
> > > 
> > > Sorry for the delayed review.  A few comments inline below, minor
> > > suggestions.
> > > 
> > > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > > > index cc12f3449a72..e6b2dcb0846a 100644
> > > > --- a/security/integrity/ima/ima.h
> > > > +++ b/security/integrity/ima/ima.h
> > > > @@ -56,6 +56,7 @@ extern int ima_policy_flag;
> > > >   extern int ima_hash_algo;
> > > >   extern int ima_appraise;
> > > >   extern struct tpm_chip *ima_tpm_chip;
> > > > +extern struct tpm_digest *digests;
> > > >   /* IMA event related data */
> > > >   struct ima_event_data {
> > > > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
> > > > index 6bb42a9c5e47..296a965b11ef 100644
> > > > --- a/security/integrity/ima/ima_init.c
> > > > +++ b/security/integrity/ima/ima_init.c
> > > > @@ -27,6 +27,7 @@
> > > >   /* name for boot aggregate entry */
> > > >   static const char boot_aggregate_name[] = "boot_aggregate";
> > > >   struct tpm_chip *ima_tpm_chip;
> > > > +struct tpm_digest *digests;
> > > 
> > > "digests" is used in the new ima_init_digests() and in
> > > ima_pcr_extend().  It's nice that the initialization routines are
> > > grouped together here in ima_init.c, but wouldn't it better to define
> > > "digests" in ima_queued.c, where it is currently being used?
> > >   "digests" could then be defined as static.
> > 
> > 'digests' and ima_init_digests() can be moved to ima_queue.c, but I have
> > to add the definition of ima_init_digests() to ima.h. Should I do it?

Yes, I think it is preferable, as it's defined as an __init.

> > 
> > 
> > > >   /* Add the boot aggregate to the IMA measurement list and extend
> > > >    * the PCR register.
> > > > @@ -104,6 +105,24 @@ void __init ima_load_x509(void)
> > > >   }
> > > >   #endif
> > > > +int __init ima_init_digests(void)
> > > > +{
> > > > +	int i;
> > > > +
> > > > +	if (!ima_tpm_chip)
> > > > +		return 0;
> > > > +
> > > > +	digests = kcalloc(ima_tpm_chip->nr_allocated_banks, sizeof(*digests),
> > > > +			  GFP_NOFS);
> > > > +	if (!digests)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
> > > > +		digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > >   int __init ima_init(void)
> > > >   {
> > > >   	int rc;
> > > > @@ -125,6 +144,9 @@ int __init ima_init(void)
> > > >   	ima_load_kexec_buffer();
> > > > +	rc = ima_init_digests();
> > > 
> > > Ok. Getting the tpm chip is at the beginning of this function.
> > >   Deferring allocating "digests" to here, avoids having to free memory
> > > on failure.
> > > 
> > > ima_load_kexec_buffer() restores prior measurements, but doesn't
> > > extend the TPM.  For anyone reading the code, a short comment above
> > > ima_load_kexec_buffer() would make sense.
> > 
> > Ok. Should I resend the last patch again with the fixes you suggested?
> 
> Send the full patch set. For me it is easier then to apply the series
> rather than cherry-picking patches from random versions of the patch
> set.

Jarkko, thanks.  I've been running with previous versions of this
patchset, and now with this latest version.

Mimi