ima: differentiate appraise status only for hook specific rules

Different hooks can require different methods for appraising a
file's integrity.  As a result, an integrity appraisal status is
cached on a per hook basis.

Only a hook specific rule, requires the inode to be re-appraised.
This patch eliminates unnecessary appraisals.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

2 files changed, 12 insertions, 6 deletions

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 66b7f408eff..3e751a9743a 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -146,7 +146,7 @@ static int process_measurement(struct file *file, const char *filename,
         struct integrity_iint_cache *iint;
         char *pathbuf = NULL;
         const char *pathname = NULL;
-        int rc = -ENOMEM, action, must_appraise;
+        int rc = -ENOMEM, action, must_appraise, _func;
 
         if (!ima_initialized || !S_ISREG(inode->i_mode))
                 return 0;
@@ -161,6 +161,9 @@ static int process_measurement(struct file *file, const char *filename,
 
         must_appraise = action & IMA_APPRAISE;
 
+        /*  Is the appraise rule hook specific?  */
+        _func = (action & IMA_FILE_APPRAISE) ? FILE_CHECK : function;
+
         mutex_lock(&inode->i_mutex);
 
         iint = integrity_inode_get(inode);
@@ -178,7 +181,7 @@ static int process_measurement(struct file *file, const char *filename,
         /* Nothing to do, just return existing appraised status */
         if (!action) {
                 if (must_appraise)
-                        rc = ima_get_cache_status(iint, function);
+                        rc = ima_get_cache_status(iint, _func);
                 goto out_digsig;
         }
 
@@ -195,7 +198,7 @@ static int process_measurement(struct file *file, const char *filename,
         if (action & IMA_MEASURE)
                 ima_store_measurement(iint, file, pathname);
         if (action & IMA_APPRAISE_SUBMASK)
-                rc = ima_appraise_measurement(function, iint, file, pathname);
+                rc = ima_appraise_measurement(_func, iint, file, pathname);
         if (action & IMA_AUDIT)
                 ima_audit_measurement(iint, pathname);
         kfree(pathbuf);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 4d7c0ae656d..4adcd0f8c1d 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -220,10 +220,13 @@ retry:
 
 /*
  * In addition to knowing that we need to appraise the file in general,
- * we need to differentiate between calling hooks.
+ * we need to differentiate between calling hooks, for hook specific rules.
  */
-static int get_subaction(int func)
+static int get_subaction(struct ima_rule_entry *rule, int func)
 {
+        if (!(rule->flags & IMA_FUNC))
+                return IMA_FILE_APPRAISE;
+
         switch(func) {
         case MMAP_CHECK:
                 return IMA_MMAP_APPRAISE;
@@ -268,7 +271,7 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 
                 action |= entry->action & IMA_DO_MASK;
                 if (entry->action & IMA_APPRAISE)
-                        action |= get_subaction(func);
+                        action |= get_subaction(entry, func);
 
                 if (entry->action & IMA_DO_MASK)
                         actmask &= ~(entry->action | entry->action << 1);