ima: do not include field length in template digest calc for ima template

To maintain compatibility with userspace tools, the field length must not
be included in the template digest calculation for the 'ima' template.

Fixes commit: a71dc65 ima: switch to new template management mechanism

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 676e0292dfec..fdf60def52e9 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -140,6 +140,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
  * Calculate the hash of template data
  */
 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
+                                         struct ima_template_desc *td,
                                          int num_fields,
                                          struct ima_digest_data *hash,
                                          struct crypto_shash *tfm)
@@ -160,9 +161,13 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
                 return rc;
 
         for (i = 0; i < num_fields; i++) {
-                rc = crypto_shash_update(&desc.shash,
-                                         (const u8 *) &field_data[i].len,
-                                         sizeof(field_data[i].len));
+                if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
+                        rc = crypto_shash_update(&desc.shash,
+                                                (const u8 *) &field_data[i].len,
+                                                sizeof(field_data[i].len));
+                        if (rc)
+                                break;
+                }
                 rc = crypto_shash_update(&desc.shash, field_data[i].data,
                                          field_data[i].len);
                 if (rc)
@@ -175,7 +180,8 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
         return rc;
 }
 
-int ima_calc_field_array_hash(struct ima_field_data *field_data, int num_fields,
+int ima_calc_field_array_hash(struct ima_field_data *field_data,
+                              struct ima_template_desc *desc, int num_fields,
                               struct ima_digest_data *hash)
 {
         struct crypto_shash *tfm;
@@ -185,7 +191,8 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data, int num_fields,
         if (IS_ERR(tfm))
                 return PTR_ERR(tfm);
 
-        rc = ima_calc_field_array_hash_tfm(field_data, num_fields, hash, tfm);
+        rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
+                                           hash, tfm);
 
         ima_free_tfm(tfm);