[PATCH] ima: Use tpm_default_chip() and call TPM functions with a tpm_chip

From: Stefan Berger
Date: Mon Jul 02 2018 - 11:25:09 EST


Rather than accessing the TPM functions by passing a NULL pointer for
the tpm_chip, which causes a lookup for a suitable chip every time, get a
hold of a tpm_chip and access the TPM functions using it. Also get rid of
the ima_used_chip variable and use the new ima_tpm_chip variable instead
for determining whether to call TPM functions.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
security/integrity/ima/ima.h | 2 +-
security/integrity/ima/ima_crypto.c | 4 ++--
security/integrity/ima/ima_init.c | 16 +++++-----------
security/integrity/ima/ima_queue.c | 4 ++--
4 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 354bb5716ce3..2ab1affffa36 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -53,9 +53,9 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
extern int ima_policy_flag;

/* set during initialization */
-extern int ima_used_chip;
extern int ima_hash_algo;
extern int ima_appraise;
+extern struct tpm_chip *ima_tpm_chip;

/* IMA event related data */
struct ima_event_data {
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 4e085a17124f..7e7e7e7c250a 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -631,10 +631,10 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,

static void __init ima_pcrread(int idx, u8 *pcr)
{
- if (!ima_used_chip)
+ if (!ima_tpm_chip)
return;

- if (tpm_pcr_read(NULL, idx, pcr) != 0)
+ if (tpm_pcr_read(ima_tpm_chip, idx, pcr) != 0)
pr_err("Error Communicating to TPM chip\n");
}

diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 29b72cd2502e..faac9ecaa0ae 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -26,7 +26,7 @@

/* name for boot aggregate entry */
static const char *boot_aggregate_name = "boot_aggregate";
-int ima_used_chip;
+struct tpm_chip *ima_tpm_chip;

/* Add the boot aggregate to the IMA measurement list and extend
* the PCR register.
@@ -64,7 +64,7 @@ static int __init ima_add_boot_aggregate(void)
iint->ima_hash->algo = HASH_ALGO_SHA1;
iint->ima_hash->length = SHA1_DIGEST_SIZE;

- if (ima_used_chip) {
+ if (ima_tpm_chip) {
result = ima_calc_boot_aggregate(&hash.hdr);
if (result < 0) {
audit_cause = "hashing_error";
@@ -106,17 +106,11 @@ void __init ima_load_x509(void)

int __init ima_init(void)
{
- u8 pcr_i[TPM_DIGEST_SIZE];
int rc;

- ima_used_chip = 0;
- rc = tpm_pcr_read(NULL, 0, pcr_i);
- if (rc == 0)
- ima_used_chip = 1;
-
- if (!ima_used_chip)
- pr_info("No TPM chip found, activating TPM-bypass! (rc=%d)\n",
- rc);
+ ima_tpm_chip = tpm_default_chip();
+ if (!ima_tpm_chip)
+ pr_info("No TPM chip found, activating TPM-bypass!\n");

rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
if (rc)
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 418f35e38015..b186819bd5aa 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -142,10 +142,10 @@ static int ima_pcr_extend(const u8 *hash, int pcr)
{
int result = 0;

- if (!ima_used_chip)
+ if (!ima_tpm_chip)
return result;

- result = tpm_pcr_extend(NULL, pcr, hash);
+ result = tpm_pcr_extend(ima_tpm_chip, pcr, hash);
if (result != 0)
pr_err("Error Communicating to TPM chip, result: %d\n", result);
return result;
--
2.17.1