ima: differentiate between template hash and file data hash sizes

The TPM v1.2 limits the template hash size to 20 bytes.  This
patch differentiates between the template hash size, as defined
in the ima_template_entry, and the file data hash size, as
defined in the ima_template_data.  Subsequent patches add support
for different file data hash algorithms.

Change log:
- hash digest definition in ima_store_template() should be TPM_DIGEST_SIZE

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

security/integrity/ima/ima.h

@@ -49,7 +49,7 @@ struct ima_template_data {
 };
 
 struct ima_template_entry {
-	u8 digest[IMA_DIGEST_SIZE];	/* sha1 or md5 measurement hash */
+	u8 digest[TPM_DIGEST_SIZE];	/* sha1 or md5 measurement hash */
 	const char *template_name;
 	int template_len;
 	struct ima_template_data template;

security/integrity/ima/ima_api.c

@@ -46,7 +46,7 @@ int ima_store_template(struct ima_template_entry *entry,
 	int result;
 	struct {
 		struct ima_digest_data hdr;
-		char digest[IMA_MAX_DIGEST_SIZE];
+		char digest[TPM_DIGEST_SIZE];
 	} hash;
 
 	memset(entry->digest, 0, sizeof(entry->digest));

security/integrity/ima/ima_crypto.c

@@ -155,7 +155,7 @@ static void __init ima_pcrread(int idx, u8 *pcr)
  */
 int __init ima_calc_boot_aggregate(char *digest)
 {
-	u8 pcr_i[IMA_DIGEST_SIZE];
+	u8 pcr_i[TPM_DIGEST_SIZE];
 	int rc, i;
 	struct {
 		struct shash_desc shash;
@@ -173,7 +173,7 @@ int __init ima_calc_boot_aggregate(char *digest)
 	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
 		ima_pcrread(i, pcr_i);
 		/* now accumulate with current aggregate */
-		rc = crypto_shash_update(&desc.shash, pcr_i, IMA_DIGEST_SIZE);
+		rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
 	}
 	if (!rc)
 		crypto_shash_final(&desc.shash, digest);

security/integrity/ima/ima_fs.c

@@ -133,7 +133,7 @@ static int ima_measurements_show(struct seq_file *m, void *v)
 	ima_putc(m, &pcr, sizeof pcr);
 
 	/* 2nd: template digest */
-	ima_putc(m, e->digest, IMA_DIGEST_SIZE);
+	ima_putc(m, e->digest, TPM_DIGEST_SIZE);
 
 	/* 3rd: template name size */
 	namelen = strlen(e->template_name);
@@ -167,11 +167,11 @@ static const struct file_operations ima_measurements_ops = {
 	.release = seq_release,
 };
 
-static void ima_print_digest(struct seq_file *m, u8 *digest)
+static void ima_print_digest(struct seq_file *m, u8 *digest, int size)
 {
 	int i;
 
-	for (i = 0; i < IMA_DIGEST_SIZE; i++)
+	for (i = 0; i < size; i++)
 		seq_printf(m, "%02x", *(digest + i));
 }
 
@@ -182,7 +182,7 @@ void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show)
 
 	switch (show) {
 	case IMA_SHOW_ASCII:
-		ima_print_digest(m, entry->digest);
+		ima_print_digest(m, entry->digest, IMA_DIGEST_SIZE);
 		seq_printf(m, " %s\n", entry->file_name);
 		break;
 	case IMA_SHOW_BINARY:
@@ -212,7 +212,7 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
 
 	/* 2nd: SHA1 template hash */
-	ima_print_digest(m, e->digest);
+	ima_print_digest(m, e->digest, TPM_DIGEST_SIZE);
 
 	/* 3th:  template name */
 	seq_printf(m, " %s ", e->template_name);

security/integrity/ima/ima_init.c

@@ -74,7 +74,7 @@ err_out:
 
 int __init ima_init(void)
 {
-	u8 pcr_i[IMA_DIGEST_SIZE];
+	u8 pcr_i[TPM_DIGEST_SIZE];
 	int rc;
 
 	ima_used_chip = 0;

security/integrity/ima/ima_queue.c

@@ -50,7 +50,7 @@ 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, IMA_DIGEST_SIZE);
+		rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
 		if (rc == 0) {
 			ret = qe;
 			break;
@@ -106,7 +106,7 @@ static int ima_pcr_extend(const u8 *hash)
 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
 			   const char *op, struct inode *inode)
 {
-	u8 digest[IMA_DIGEST_SIZE];
+	u8 digest[TPM_DIGEST_SIZE];
 	const char *audit_cause = "hash_added";
 	char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
 	int audit_info = 1;