ima: per hook cache integrity appraisal status

With the new IMA policy 'appraise_type=' option, different hooks
can require different methods for appraising a file's integrity.

For example, the existing 'ima_appraise_tcb' policy defines a
generic rule, requiring all root files to be appraised, without
specfying the appraisal method.  A more specific rule could require
all kernel modules, for example, to be signed.

appraise fowner=0 func=MODULE_CHECK appraise_type=imasig
appraise fowner=0

As a result, the integrity appraisal results for the same inode, but
for different hooks, could differ.  This patch caches the integrity
appraisal results on a per hook basis.

Changelog v2:
- Rename ima_cache_status() to ima_set_cache_status()
- Rename and move get_appraise_status() to ima_get_cache_status()
Changelog v0:
- include IMA_APPRAISE/APPRAISED_SUBMASK in IMA_DO/DONE_MASK (Dmitry)
- Support independent MODULE_CHECK appraise status.
- fixed IMA_XXXX_APPRAISE/APPRAISED flags

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

1 files changed, 11 insertions, 2 deletions

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 991844db98d9..ab68bed8ac36 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -142,13 +142,16 @@ void ima_delete_rules(void);
 #define IMA_APPRAISE_FIX	0x02
 
 #ifdef CONFIG_IMA_APPRAISE
-int ima_appraise_measurement(struct integrity_iint_cache *iint,
+int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename);
 int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
 void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
+enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
+					   int func);
 
 #else
-static inline int ima_appraise_measurement(struct integrity_iint_cache *iint,
+static inline int ima_appraise_measurement(int func,
+					   struct integrity_iint_cache *iint,
 					   struct file *file,
 					   const unsigned char *filename)
 {
@@ -165,6 +168,12 @@ static inline void ima_update_xattr(struct integrity_iint_cache *iint,
 				    struct file *file)
 {
 }
+
+static inline enum integrity_status ima_get_cache_status(struct integrity_iint_cache
+							 *iint, int func)
+{
+	return INTEGRITY_UNKNOWN;
+}
 #endif
 
 /* LSM based policy rules require audit */