[PATCH 2/3] IMA: update functions to read allow_dup policy condition

[Tushar Sugandhi <tusharsu@linux.microsoft.com>]

IMA functions ima_get_action() and ima_match_policy() do not consume the
policy condition to allow measuring duplicate entries for integrity
critical data.

Update ima_get_action() and ima_match_policy() to consume the IMA policy
condition to measure duplicate buffer entries for integrity critical
data.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
---
 security/integrity/ima/ima.h          | 4 ++--
 security/integrity/ima/ima_api.c      | 6 ++++--
 security/integrity/ima/ima_appraise.c | 2 +-
 security/integrity/ima/ima_main.c     | 6 +++---
 security/integrity/ima/ima_policy.c   | 7 ++++++-
 5 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index aa312472c7c5..59324173497f 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -257,7 +257,7 @@ static inline void ima_process_queued_keys(void) {}
 int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 		   int mask, enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
-		   const char *func_data);
+		   const char *func_data, bool *allow_dup);
 int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
 int ima_collect_measurement(struct integrity_iint_cache *iint,
 			    struct file *file, void *buf, loff_t size,
@@ -286,7 +286,7 @@ const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
 		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
-		     const char *func_data);
+		     const char *func_data, bool *allow_dup);
 void ima_init_policy(void);
 void ima_update_policy(void);
 void ima_update_policy_flag(void);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 1dd70dc68ffd..d273373e6be9 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -171,6 +171,8 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
  * @pcr: pointer filled in if matched measure policy sets pcr=
  * @template_desc: pointer filled in if matched measure policy sets template=
  * @func_data: func specific data, may be NULL
+ * @allow_dup: pointer filled in to decide if a duplicate buffer entry
+ *             should be measured
  *
  * The policy is defined in terms of keypairs:
  *		subj=, obj=, type=, func=, mask=, fsmagic=
@@ -186,14 +188,14 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
 int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 		   int mask, enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
-		   const char *func_data)
+		   const char *func_data, bool *allow_dup)
 {
 	int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;
 
 	flags &= ima_policy_flag;
 
 	return ima_match_policy(inode, cred, secid, func, mask, flags, pcr,
-				template_desc, func_data);
+				template_desc, func_data, allow_dup);
 }
 
 /*
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 46ffa38bab12..e317a7698a47 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -77,7 +77,7 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
 
 	security_task_getsecid(current, &secid);
 	return ima_match_policy(inode, current_cred(), secid, func, mask,
-				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
+				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL, NULL);
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 6a429846f90a..2774139845b6 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -219,7 +219,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	 * Included is the appraise submask.
 	 */
 	action = ima_get_action(inode, cred, secid, mask, func, &pcr,
-				&template_desc, NULL);
+				&template_desc, NULL, NULL);
 	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
 			   (ima_policy_flag & IMA_MEASURE));
 	if (!action && !violation_check)
@@ -432,7 +432,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	security_task_getsecid(current, &secid);
 	inode = file_inode(vma->vm_file);
 	action = ima_get_action(inode, current_cred(), secid, MAY_EXEC,
-				MMAP_CHECK, &pcr, &template, 0);
+				MMAP_CHECK, &pcr, &template, 0, NULL);
 
 	/* Is the mmap'ed file in policy? */
 	if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
@@ -865,7 +865,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
 	if (func) {
 		security_task_getsecid(current, &secid);
 		action = ima_get_action(inode, current_cred(), secid, 0, func,
-					&pcr, &template, func_data);
+					&pcr, &template, func_data, NULL);
 		if (!(action & IMA_MEASURE))
 			return;
 	}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index b89eb768dd05..4147c677eb24 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -644,6 +644,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * @pcr: set the pcr to extend
  * @template_desc: the template that should be used for this rule
  * @func_data: func specific data, may be NULL
+ * @allow_dup: pointer filled in to decide if a duplicate buffer entry
+ *             should be measured
  *
  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
  * conditions.
@@ -655,7 +657,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
 		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
-		     const char *func_data)
+		     const char *func_data, bool *allow_dup)
 {
 	struct ima_rule_entry *entry;
 	int action = 0, actmask = flags | (flags << 1);
@@ -673,6 +675,9 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
 				     func_data))
 			continue;
 
+		if ((allow_dup) && (func == CRITICAL_DATA))
+			*allow_dup = entry->allow_dup;
+
 		action |= entry->flags & IMA_ACTION_FLAGS;
 
 		action |= entry->action & IMA_DO_MASK;
-- 
2.17.1