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authorMaurizio Drocco <maurizio.drocco@ibm.com>2020-06-23 11:57:32 -0400
committerMimi Zohar <zohar@linux.ibm.com>2020-06-24 20:47:24 -0400
commit20c59ce010f84300f6c655d32db2610d3433f85c (patch)
tree36dc25b12cddb87b4a200819375398cf5a3917a3 /security
parent48778464bb7d346b47157d21ffde2af6b2d39110 (diff)
ima: extend boot_aggregate with kernel measurements
Registers 8-9 are used to store measurements of the kernel and its command line (e.g., grub2 bootloader with tpm module enabled). IMA should include them in the boot aggregate. Registers 8-9 should be only included in non-SHA1 digests to avoid ambiguity. Signed-off-by: Maurizio Drocco <maurizio.drocco@ibm.com> Reviewed-by: Bruno Meneguele <bmeneg@redhat.com> Tested-by: Bruno Meneguele <bmeneg@redhat.com> (TPM 1.2, TPM 2.0) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/ima/ima.h2
-rw-r--r--security/integrity/ima/ima_crypto.c15
2 files changed, 15 insertions, 2 deletions
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index df93ac258e01..9d94080bdad8 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -30,7 +30,7 @@
enum ima_show_type { IMA_SHOW_BINARY, IMA_SHOW_BINARY_NO_FIELD_LEN,
IMA_SHOW_BINARY_OLD_STRING_FMT, IMA_SHOW_ASCII };
-enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
+enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8, TPM_PCR10 = 10 };
/* digest size for IMA, fits SHA1 or MD5 */
#define IMA_DIGEST_SIZE SHA1_DIGEST_SIZE
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 220b14920c37..011c3c76af86 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -823,13 +823,26 @@ static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
if (rc != 0)
return rc;
- /* cumulative sha1 over tpm registers 0-7 */
+ /* cumulative digest over TPM registers 0-7 */
for (i = TPM_PCR0; i < TPM_PCR8; i++) {
ima_pcrread(i, &d);
/* now accumulate with current aggregate */
rc = crypto_shash_update(shash, d.digest,
crypto_shash_digestsize(tfm));
}
+ /*
+ * Extend cumulative digest over TPM registers 8-9, which contain
+ * measurement for the kernel command line (reg. 8) and image (reg. 9)
+ * in a typical PCR allocation. Registers 8-9 are only included in
+ * non-SHA1 boot_aggregate digests to avoid ambiguity.
+ */
+ if (alg_id != TPM_ALG_SHA1) {
+ for (i = TPM_PCR8; i < TPM_PCR10; i++) {
+ ima_pcrread(i, &d);
+ rc = crypto_shash_update(shash, d.digest,
+ crypto_shash_digestsize(tfm));
+ }
+ }
if (!rc)
crypto_shash_final(shash, digest);
return rc;