-----Original Message-----
From: Roberto Sassu
Sent: Wednesday, February 5, 2020 11:33 AM
To: zohar@linux.ibm.com; James.Bottomley@HansenPartnership.com;
jarkko.sakkinen@linux.intel.com
Cc: linux-integrity@vger.kernel.org; linux-security-module@vger.kernel.org;
linux-kernel@vger.kernel.org; Silviu Vlasceanu
[off-list ref]; Roberto Sassu
[off-list ref]
Subject: [PATCH v2 5/8] ima: Switch to dynamically allocated buffer for
template digests

This patch dynamically allocates the array of tpm_digest structures in
ima_alloc_init_template() and ima_restore_template_data(). The size of
the
array, stored in ima_num_template_digests, is initially equal to 1 (SHA1)
and will be determined in the upcoming patches depending on the allocated
PCR banks and the chosen default IMA algorithm.

Calculating the SHA1 digest is mandatory, as SHA1 still remains the default
hash algorithm for the measurement list. When IMA will support the Crypto
Agile format, remaining digests will be also provided.

The position in the array of the SHA1 digest is stored in the ima_sha1_idx
global variable and it is determined at IMA initialization time.

Changelog

v1:
- move ima_sha1_idx to ima_crypto.c
- introduce ima_num_template_digests (suggested by Mimi)

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 security/integrity/ima/ima.h          |  4 +++-
 security/integrity/ima/ima_api.c      |  8 ++++++++
 security/integrity/ima/ima_crypto.c   |  6 +++++-
 security/integrity/ima/ima_fs.c       |  4 ++--
 security/integrity/ima/ima_queue.c    | 10 ++++++----
 security/integrity/ima/ima_template.c | 12 ++++++++++--
 6 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 2f380fb92a7a..4843077dc9e8 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h

@@ -50,6 +50,8 @@ extern int ima_policy_flag;

 /* set during initialization */
 extern int ima_hash_algo;
+extern int ima_sha1_idx;
+extern int ima_num_template_digests;
 extern int ima_appraise;
 extern struct tpm_chip *ima_tpm_chip;

@@ -92,7 +94,7 @@ struct ima_template_desc {

 struct ima_template_entry {
 	int pcr;
-	u8 digest[TPM_DIGEST_SIZE];	/* sha1 or md5 measurement hash

*/
+	struct tpm_digest *digests;
 	struct ima_template_desc *template_desc; /* template descriptor
*/
 	u32 template_data_len;
 	struct ima_field_data template_data[0];	/* template related
data */

diff --git a/security/integrity/ima/ima_api.c

b/security/integrity/ima/ima_api.c
index 51f562111864..2ced5975c16f 100644

--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c

@@ -27,6 +27,7 @@ void ima_free_template_entry(struct

ima_template_entry *entry)
 	for (i = 0; i < entry->template_desc->num_fields; i++)
 		kfree(entry->template_data[i].data);

+	kfree(entry->digests);
 	kfree(entry);
 }

@@ -50,6 +51,13 @@ int ima_alloc_init_template(struct ima_event_data

*event_data,
 	if (!*entry)
 		return -ENOMEM;

+	(*entry)->digests = kcalloc(ima_num_template_digests,
+				    sizeof(*(*entry)->digests), GFP_NOFS);
+	if (!(*entry)->digests) {
+		result = -ENOMEM;
+		goto out;
+	}
+
 	(*entry)->template_desc = template_desc;
 	for (i = 0; i < template_desc->num_fields; i++) {
 		const struct ima_template_field *field =

diff --git a/security/integrity/ima/ima_crypto.c

b/security/integrity/ima/ima_crypto.c
index 2d356ae8e823..31f2497a3ab8 100644

--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c

@@ -59,6 +59,9 @@ MODULE_PARM_DESC(ahash_bufsize, "Maximum

ahash buffer size");
 static struct crypto_shash *ima_shash_tfm;
 static struct crypto_ahash *ima_ahash_tfm;

+int ima_sha1_idx;
+int ima_num_template_digests = 1;

 int __init ima_init_crypto(void)
 {
 	long rc;

@@ -502,7 +505,8 @@ static int ima_calc_field_array_hash_tfm(struct

ima_field_data *field_data,
 	}

 	if (!rc)
-		rc = crypto_shash_final(shash, entry->digest);
+		rc = crypto_shash_final(shash,
+					entry-

quoted

digests[ima_sha1_idx].digest);

 	return rc;
 }

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 2000e8df0301..2b79581d0e25 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c

@@ -152,7 +152,7 @@ int ima_measurements_show(struct seq_file *m,

void *v)
 	ima_putc(m, &pcr, sizeof(e->pcr));

 	/* 2nd: template digest */
-	ima_putc(m, e->digest, TPM_DIGEST_SIZE);
+	ima_putc(m, e->digests[ima_sha1_idx].digest, TPM_DIGEST_SIZE);

 	/* 3rd: template name size */
 	namelen = !ima_canonical_fmt ? strlen(template_name) :

@@ -235,7 +235,7 @@ static int ima_ascii_measurements_show(struct

seq_file *m, void *v)
 	seq_printf(m, "%2d ", e->pcr);

 	/* 2nd: SHA1 template hash */
-	ima_print_digest(m, e->digest, TPM_DIGEST_SIZE);
+	ima_print_digest(m, e->digests[ima_sha1_idx].digest,
TPM_DIGEST_SIZE);

 	/* 3th:  template name */
 	seq_printf(m, " %s", template_name);

diff --git a/security/integrity/ima/ima_queue.c

b/security/integrity/ima/ima_queue.c
index 1ce8b1701566..bcd99db9722c 100644

--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c

@@ -57,7 +57,8 @@ static struct ima_queue_entry

*ima_lookup_digest_entry(u8 *digest_value,
 	key = ima_hash_key(digest_value);
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
-		rc = memcmp(qe->entry->digest, digest_value,
TPM_DIGEST_SIZE);
+		rc = memcmp(qe->entry->digests[ima_sha1_idx].digest,
+			    digest_value, TPM_DIGEST_SIZE);
 		if ((rc == 0) && (qe->entry->pcr == pcr)) {
 			ret = qe;
 			break;

@@ -77,7 +78,7 @@ static int get_binary_runtime_size(struct

ima_template_entry *entry)
 	int size = 0;

 	size += sizeof(u32);	/* pcr */
-	size += sizeof(entry->digest);
+	size += TPM_DIGEST_SIZE;
 	size += sizeof(int);	/* template name size field */
 	size += strlen(entry->template_desc->name);
 	size += sizeof(entry->template_data_len);

@@ -109,7 +110,7 @@ static int ima_add_digest_entry(struct

ima_template_entry *entry,

 	atomic_long_inc(&ima_htable.len);
 	if (update_htable) {
-		key = ima_hash_key(entry->digest);
+		key = ima_hash_key(entry->digests[ima_sha1_idx].digest);
 		hlist_add_head_rcu(&qe->hnext,
&ima_htable.queue[key]);
 	}

@@ -173,7 +174,8 @@ int ima_add_template_entry(struct

ima_template_entry *entry, int violation,

 	mutex_lock(&ima_extend_list_mutex);
 	if (!violation) {
-		memcpy(digest, entry->digest, sizeof(digest));
+		memcpy(digest, entry->digests[ima_sha1_idx].digest,
+		       sizeof(digest));
 		if (ima_lookup_digest_entry(digest, entry->pcr)) {
 			audit_cause = "hash_exists";
 			result = -EEXIST;

diff --git a/security/integrity/ima/ima_template.c

b/security/integrity/ima/ima_template.c
index 6aa6408603e3..751f101ae927 100644

--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c

@@ -311,11 +311,19 @@ static int ima_restore_template_data(struct

ima_template_desc *template_desc,
 	if (!*entry)
 		return -ENOMEM;

+	(*entry)->digests = kcalloc(ima_num_template_digests,
+				    sizeof(*(*entry)->digests), GFP_NOFS);
+	if (!(*entry)->digests) {
+		kfree(*entry);
+		return -ENOMEM;
+	}
+
 	ret = ima_parse_buf(template_data, template_data +
template_data_size,
 			    NULL, template_desc->num_fields,
 			    (*entry)->template_data, NULL, NULL,
 			    ENFORCE_FIELDS | ENFORCE_BUFEND, "template
data");
 	if (ret < 0) {
+		kfree((*entry)->digests);
 		kfree(*entry);
 		return ret;
 	}

@@ -447,8 +455,8 @@ int ima_restore_measurement_list(loff_t size, void

*buf)
 		if (ret < 0)
 			break;

-		memcpy(entry->digest, hdr[HDR_DIGEST].data,
-		       hdr[HDR_DIGEST].len);
+		memcpy(entry->digests[ima_sha1_idx].digest,
+		       hdr[HDR_DIGEST].data, hdr[HDR_DIGEST].len);
 		entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) :
 			     le32_to_cpu(*(hdr[HDR_PCR].data));
 		ret = ima_restore_measurement_entry(entry);
--
2.17.1