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Message-Id: <20201206111555.310303768@linuxfoundation.org>
Date: Sun, 6 Dec 2020 12:17:17 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Maurizio Drocco <maurizio.drocco@....com>,
Bruno Meneguele <bmeneg@...hat.com>,
Mimi Zohar <zohar@...ux.ibm.com>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 13/39] ima: extend boot_aggregate with kernel measurements
From: Maurizio Drocco <maurizio.drocco@....com>
[ Upstream commit 20c59ce010f84300f6c655d32db2610d3433f85c ]
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@....com>
Reviewed-by: Bruno Meneguele <bmeneg@...hat.com>
Tested-by: Bruno Meneguele <bmeneg@...hat.com> (TPM 1.2, TPM 2.0)
Signed-off-by: Mimi Zohar <zohar@...ux.ibm.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
security/integrity/ima/ima.h | 2 +-
security/integrity/ima/ima_crypto.c | 15 ++++++++++++++-
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 8173982e00ab5..5fae6cfe8d910 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 d86825261b515..b06baf5d3cd32 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -682,7 +682,7 @@ 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 */
@@ -691,6 +691,19 @@ static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id,
if (rc != 0)
return rc;
}
+ /*
+ * 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;
--
2.27.0
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