From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
"James.Bottomley@HansenPartnership.com"
<James.Bottomley@HansenPartnership.com>,
"jarkko.sakkinen@linux.intel.com"
<jarkko.sakkinen@linux.intel.com>
Cc: "linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Silviu Vlasceanu <Silviu.Vlasceanu@huawei.com>
Subject: Re: [PATCH v2 5/8] ima: Switch to dynamically allocated buffer for template digests
Date: Thu, 06 Feb 2020 11:33:54 -0500 [thread overview]
Message-ID: <1581006834.5585.430.camel@linux.ibm.com> (raw)
In-Reply-To: <0b91e6977bac4cd5a638041adb3e76eb@huawei.com>
On Thu, 2020-02-06 at 16:27 +0000, Roberto Sassu wrote:
> > -----Original Message-----
> > From: Mimi Zohar [mailto:zohar@linux.ibm.com]
> > Sent: Thursday, February 6, 2020 5:08 PM
> > To: Roberto Sassu <roberto.sassu@huawei.com>;
> > James.Bottomley@HansenPartnership.com;
> > jarkko.sakkinen@linux.intel.com
> > Cc: linux-integrity@vger.kernel.org; linux-security-module@vger.kernel.org;
> > linux-kernel@vger.kernel.org; Silviu Vlasceanu
> > <Silviu.Vlasceanu@huawei.com>
> > Subject: Re: [PATCH v2 5/8] ima: Switch to dynamically allocated buffer for
> > template digests
> >
> > Hi Roberto,
> >
> > On Wed, 2020-02-05 at 11:33 +0100, Roberto Sassu wrote:
> > > This patch dynamically allocates the array of tpm_digest structures in
> > > ima_alloc_init_template() and ima_restore_template_data(). The size of
> > the
> > > array, stored in ima_num_template_digests, is initially equal to 1 (SHA1)
> > > and will be determined in the upcoming patches depending on the
> > allocated
> > > PCR banks and the chosen default IMA algorithm.
> > >
> > > Calculating the SHA1 digest is mandatory, as SHA1 still remains the default
> > > hash algorithm for the measurement list. When IMA will support the
> > Crypto
> > > Agile format, remaining digests will be also provided.
> > >
> > > The position in the array of the SHA1 digest is stored in the ima_sha1_idx
> > > global variable and it is determined at IMA initialization time.
> > >
> > > Changelog
> > >
> > > v1:
> > > - move ima_sha1_idx to ima_crypto.c
> > > - introduce ima_num_template_digests (suggested by Mimi)
> >
> > Instead of hardcoding "nr_allocated_banks + 1" or nr_allocated_banks +
> > 2", I suggested defining "nr_allocated_banks + extra", where "extra"
> > could be 0, 1, or 2.
> >
> > The rest of the code would remain exactly the same as you had.
>
> Ok. I did a small improvement. Since we determine the number of
> required elements of ima_algo_array before kmalloc() I thought it
> was ok to directly set that number of elements in a single variable.
>
> If you think that having two variables is better, I will change it.
The connection to nr_allocated_banks is then not as visible. Using
two variables is clearer.
Mimi
next prev parent reply other threads:[~2020-02-06 16:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 10:33 [PATCH v2 0/8] ima: support stronger algorithms for attestation Roberto Sassu
2020-02-05 10:33 ` [PATCH v2 1/8] tpm: Initialize crypto_id of allocated_banks to HASH_ALGO__LAST Roberto Sassu
2020-02-05 21:57 ` Jarkko Sakkinen
2020-02-05 10:33 ` [PATCH v2 2/8] ima: Switch to ima_hash_algo for boot aggregate Roberto Sassu
[not found] ` <20200205144515.1DDE4217F4@mail.kernel.org>
2020-02-05 15:36 ` Roberto Sassu
2020-02-05 20:41 ` Mimi Zohar
2020-02-06 9:33 ` Roberto Sassu
2020-02-05 21:00 ` Mimi Zohar
2020-02-06 9:36 ` Roberto Sassu
2020-02-06 12:17 ` Mimi Zohar
2020-02-06 12:28 ` Roberto Sassu
2020-02-06 12:31 ` Mimi Zohar
2020-02-05 10:33 ` [PATCH v2 3/8] ima: Evaluate error in init_ima() Roberto Sassu
2020-02-05 10:39 ` Roberto Sassu
2020-02-05 10:33 ` [PATCH v2 4/8] ima: Store template digest directly in ima_template_entry Roberto Sassu
2020-02-05 10:33 ` [PATCH v2 5/8] ima: Switch to dynamically allocated buffer for template digests Roberto Sassu
2020-02-05 16:39 ` Roberto Sassu
2020-02-06 16:08 ` Mimi Zohar
2020-02-06 16:27 ` Roberto Sassu
2020-02-06 16:33 ` Mimi Zohar [this message]
2020-02-06 16:36 ` Roberto Sassu
2020-02-05 10:33 ` [PATCH v2 6/8] ima: Allocate and initialize tfm for each PCR bank Roberto Sassu
2020-02-05 23:41 ` kbuild test robot
2020-02-05 23:41 ` [RFC PATCH] ima: ima_init_ima_crypto() can be static kbuild test robot
2020-02-05 10:33 ` [PATCH v2 7/8] ima: Calculate and extend PCR with digests in ima_template_entry Roberto Sassu
2020-02-05 10:33 ` [PATCH v2 8/8] ima: Use ima_hash_algo for collision detection in the measurement list Roberto Sassu
[not found] ` <20200302012218.GU6548@shao2-debian>
2020-03-02 9:46 ` [ima] 9165b814d2: BUG:kernel_NULL_pointer_dereference,address Roberto Sassu
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