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authorRoberto Sassu <roberto.sassu@huawei.com>2020-03-25 11:53:50 +0100
committerMimi Zohar <zohar@linux.ibm.com>2020-04-19 22:03:39 -0400
commit1ea973df6e2166d1a576cabe5d08925d3261ff9d (patch)
tree7e17b50d0a5cb7c630bd404c4a51727042f71438
parent6d94809af6b0830c4dfcad661535a5939bcb8a7d (diff)
downloadlinux-1ea973df6e2166d1a576cabe5d08925d3261ff9d.tar.gz
ima: Calculate and extend PCR with digests in ima_template_entry
This patch modifies ima_calc_field_array_hash() to calculate a template digest for each allocated PCR bank and SHA1. It also passes the tpm_digest array of the template entry to ima_pcr_extend() or in case of a violation, the pre-initialized digests array filled with 0xff. Padding with zeros is still done if the mapping between TPM algorithm ID and crypto ID is unknown. This patch calculates again the template digest when a measurement list is restored. Copying only the SHA1 digest (due to the limitation of the current measurement list format) is not sufficient, as hash collision detection will be done on the digest calculated with the IMA default hash algorithm. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
-rw-r--r--security/integrity/ima/ima_crypto.c29
-rw-r--r--security/integrity/ima/ima_queue.c30
-rw-r--r--security/integrity/ima/ima_template.c14
3 files changed, 58 insertions, 15 deletions
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index ab1c05ad1314..a94972d3f929 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -619,9 +619,36 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
int ima_calc_field_array_hash(struct ima_field_data *field_data,
struct ima_template_entry *entry)
{
- int rc;
+ u16 alg_id;
+ int rc, i;
rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx);
+ if (rc)
+ return rc;
+
+ entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1;
+
+ for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) {
+ if (i == ima_sha1_idx)
+ continue;
+
+ if (i < NR_BANKS(ima_tpm_chip)) {
+ alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
+ entry->digests[i].alg_id = alg_id;
+ }
+
+ /* for unmapped TPM algorithms digest is still a padded SHA1 */
+ if (!ima_algo_array[i].tfm) {
+ memcpy(entry->digests[i].digest,
+ entry->digests[ima_sha1_idx].digest,
+ TPM_DIGEST_SIZE);
+ continue;
+ }
+
+ rc = ima_calc_field_array_hash_tfm(field_data, entry, i);
+ if (rc)
+ return rc;
+ }
return rc;
}
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 49db71c200b4..82a9ca43b989 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -135,18 +135,14 @@ unsigned long ima_get_binary_runtime_size(void)
return binary_runtime_size + sizeof(struct ima_kexec_hdr);
};
-static int ima_pcr_extend(const u8 *hash, int pcr)
+static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
{
int result = 0;
- int i;
if (!ima_tpm_chip)
return result;
- for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
- memcpy(digests[i].digest, hash, TPM_DIGEST_SIZE);
-
- result = tpm_pcr_extend(ima_tpm_chip, pcr, digests);
+ result = tpm_pcr_extend(ima_tpm_chip, pcr, digests_arg);
if (result != 0)
pr_err("Error Communicating to TPM chip, result: %d\n", result);
return result;
@@ -164,7 +160,8 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
const unsigned char *filename)
{
- u8 digest[TPM_DIGEST_SIZE];
+ u8 *digest = entry->digests[ima_sha1_idx].digest;
+ struct tpm_digest *digests_arg = entry->digests;
const char *audit_cause = "hash_added";
char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
int audit_info = 1;
@@ -172,8 +169,6 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
mutex_lock(&ima_extend_list_mutex);
if (!violation) {
- memcpy(digest, entry->digests[ima_sha1_idx].digest,
- sizeof(digest));
if (ima_lookup_digest_entry(digest, entry->pcr)) {
audit_cause = "hash_exists";
result = -EEXIST;
@@ -189,9 +184,9 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
}
if (violation) /* invalidate pcr */
- memset(digest, 0xff, sizeof(digest));
+ digests_arg = digests;
- tpmresult = ima_pcr_extend(digest, entry->pcr);
+ tpmresult = ima_pcr_extend(digests_arg, entry->pcr);
if (tpmresult != 0) {
snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
tpmresult);
@@ -217,6 +212,8 @@ int ima_restore_measurement_entry(struct ima_template_entry *entry)
int __init ima_init_digests(void)
{
+ u16 digest_size;
+ u16 crypto_id;
int i;
if (!ima_tpm_chip)
@@ -227,8 +224,17 @@ int __init ima_init_digests(void)
if (!digests)
return -ENOMEM;
- for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
+ for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) {
digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
+ digest_size = ima_tpm_chip->allocated_banks[i].digest_size;
+ crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id;
+
+ /* for unmapped TPM algorithms digest is still a padded SHA1 */
+ if (crypto_id == HASH_ALGO__LAST)
+ digest_size = SHA1_DIGEST_SIZE;
+
+ memset(digests[i].digest, 0xff, digest_size);
+ }
return 0;
}
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index de84252e65e9..5a2def40a733 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -357,6 +357,7 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc,
int ima_restore_measurement_list(loff_t size, void *buf)
{
char template_name[MAX_TEMPLATE_NAME_LEN];
+ unsigned char zero[TPM_DIGEST_SIZE] = { 0 };
struct ima_kexec_hdr *khdr = buf;
struct ima_field_data hdr[HDR__LAST] = {
@@ -456,8 +457,17 @@ int ima_restore_measurement_list(loff_t size, void *buf)
if (ret < 0)
break;
- memcpy(entry->digests[ima_sha1_idx].digest,
- hdr[HDR_DIGEST].data, hdr[HDR_DIGEST].len);
+ if (memcmp(hdr[HDR_DIGEST].data, zero, sizeof(zero))) {
+ ret = ima_calc_field_array_hash(
+ &entry->template_data[0],
+ entry);
+ if (ret < 0) {
+ pr_err("cannot calculate template digest\n");
+ ret = -EINVAL;
+ break;
+ }
+ }
+
entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) :
le32_to_cpu(*(hdr[HDR_PCR].data));
ret = ima_restore_measurement_entry(entry);