From: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: Jerry Snitselaar <jsnitsel@redhat.com>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
linux-kernel@vger.kernel.org, Mimi Zohar <zohar@linux.ibm.com>
Subject: [PATCH 1/2] ima: use the IMA configured hash algo to calculate the boot aggregate
Date: Mon, 27 Jan 2020 11:01:58 -0500 [thread overview]
Message-ID: <1580140919-6127-1-git-send-email-zohar@linux.ibm.com> (raw)
The boot aggregate is a cumulative SHA1 hash over TPM registers 0 - 7.
NIST has depreciated the usage of SHA1 in most instances. Instead of
continuing to use SHA1 to calculate the boot_aggregate, use the
configured IMA default hash algorithm.
Although the IMA measurement list boot_aggregate template data contains
the hash algorithm followed by the digest, allowing verifiers (e.g.
attesttaion servers) to calculate and verify the boot_aggregate, the
verifiers might not have the knowledge of what constitutes a good value
based on a different hash algorithm.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
security/integrity/ima/ima_init.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 195cb4079b2b..b1b334fe0db5 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -27,7 +27,7 @@ struct tpm_chip *ima_tpm_chip;
/* Add the boot aggregate to the IMA measurement list and extend
* the PCR register.
*
- * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
+ * Calculate the boot aggregate, a hash over tpm registers 0-7,
* assuming a TPM chip exists, and zeroes if the TPM chip does not
* exist. Add the boot aggregate measurement to the measurement
* list and extend the PCR register.
@@ -51,14 +51,14 @@ static int __init ima_add_boot_aggregate(void)
int violation = 0;
struct {
struct ima_digest_data hdr;
- char digest[TPM_DIGEST_SIZE];
+ char digest[TPM_MAX_DIGEST_SIZE];
} hash;
memset(iint, 0, sizeof(*iint));
memset(&hash, 0, sizeof(hash));
iint->ima_hash = &hash.hdr;
- iint->ima_hash->algo = HASH_ALGO_SHA1;
- iint->ima_hash->length = SHA1_DIGEST_SIZE;
+ iint->ima_hash->algo = ima_hash_algo;
+ iint->ima_hash->length = hash_digest_size[ima_hash_algo];
if (ima_tpm_chip) {
result = ima_calc_boot_aggregate(&hash.hdr);
--
2.7.5
next reply other threads:[~2020-01-27 16:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 16:01 Mimi Zohar [this message]
2020-01-27 16:01 ` [PATCH 2/2] ima: support calculating the boot_aggregate based on different TPM banks Mimi Zohar
2020-01-27 16:50 ` Lakshmi Ramasubramanian
2020-01-27 18:01 ` Mimi Zohar
2020-01-27 20:55 ` Ken Goldman
2020-01-28 14:19 ` Roberto Sassu
2020-01-28 15:40 ` Mimi Zohar
2020-01-28 16:31 ` Roberto Sassu
2020-01-29 23:20 ` Mimi Zohar
2020-01-30 7:31 ` James Bottomley
2020-01-27 17:38 ` [PATCH 1/2] ima: use the IMA configured hash algo to calculate the boot aggregate Roberto Sassu
2020-01-27 18:16 ` Mimi Zohar
2020-01-27 18:35 ` Mimi Zohar
2020-01-27 20:49 ` Jerry Snitselaar
2020-01-27 21:31 ` Mimi Zohar
2020-01-29 8:30 ` Petr Vorel
2020-01-29 22:51 ` Mimi Zohar
2020-01-30 8:41 ` Petr Vorel
2020-01-30 15:27 ` Roberto Sassu
2020-01-30 15:40 ` Roberto Sassu
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