Messages in this thread | | | From | Roberto Sassu <> | Subject | RE: [PATCH v3 7/8] ima: Calculate and extend PCR with digests in ima_template_entry | Date | Wed, 18 Mar 2020 12:42:40 +0000 |
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> -----Original Message----- > From: owner-linux-security-module@vger.kernel.org [mailto:owner-linux- > security-module@vger.kernel.org] On Behalf Of Mimi Zohar > Sent: Tuesday, March 3, 2020 5:04 AM > 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 v3 7/8] ima: Calculate and extend PCR with digests in > ima_template_entry > > On Mon, 2020-02-10 at 11:04 +0100, Roberto Sassu wrote: > > > @@ -219,6 +214,8 @@ int ima_restore_measurement_entry(struct > ima_template_entry *entry) > > > > int __init ima_init_digests(void) > > { > > + u16 digest_size; > > + u16 crypto_id; > > int i; > > > > if (!ima_tpm_chip) > > @@ -229,8 +226,17 @@ int __init ima_init_digests(void) > > if (!digests) > > return -ENOMEM; > > > > - for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) > > + for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) { > > digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id; > > + digest_size = ima_tpm_chip->allocated_banks[i].digest_size; > > + crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id; > > + > > + /* for unmapped TPM algorithms digest is still a padded > SHA1 */ > > + if (crypto_id == HASH_ALGO__LAST) > > + digest_size = SHA1_DIGEST_SIZE; > > + > > + memset(digests[i].digest, 0xff, digest_size); > > Shouldn't the memset here be of the actual digest size even for > unmapped TPM algorithms.
This is consistent with ima_calc_field_array_hash(), so that a verifier will always pad the SHA1 digest with zeros to obtain the final PCR value.
I can set all bytes if you prefer.
Thanks
Roberto
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli
> > + } > > > > return 0; > > }
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