On Mon Jan 27 20, Mimi Zohar wrote:
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@xxxxxxxxxxxxx>
---
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
Tested the patches on the Dell and no longer spits out the error messages on boot.
/sys/kernel/security/ima/ascii_runtime_measurements shows the boot aggregate.
Is there something else I should look at to verify it is functioning properly?
Regards,
Jerry
