ima: change integrity cache to store measured pcr

IMA avoids re-measuring files by storing the current state as a flag in
the integrity cache. It will then skip adding a new measurement log entry
if the cache reports the file as already measured.

If a policy measures an already measured file to a new PCR, the measurement
will not be added to the list. This patch implements a new bitfield for
specifying which PCR the file was measured into, rather than if it was
measured.

Signed-off-by: Eric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 8363ba384992..9df26a2b75ba 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -266,7 +266,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 					    xattr_len, NULL};
 	int violation = 0;
 
-	if (iint->flags & IMA_MEASURED)
+	if (iint->measured_pcrs & (0x1 << pcr))
 		return;
 
 	result = ima_alloc_init_template(&event_data, &entry);
@@ -277,8 +277,10 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 	}
 
 	result = ima_store_template(entry, violation, inode, filename, pcr);
-	if (!result || result == -EEXIST)
+	if (!result || result == -EEXIST) {
 		iint->flags |= IMA_MEASURED;
+		iint->measured_pcrs |= (0x1 << pcr);
+	}
 	if (result < 0)
 		ima_free_template_entry(entry);
 }