ima: remove firmware and module specific cached status info

Each time a file is read by the kernel, the file should be re-measured and
the file signature re-appraised, based on policy.  As there is no need to
preserve the status information, this patch replaces the firmware and
module specific cache status with a generic one named read_file.

This change simplifies adding support for other files read by the kernel.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Petko Manolov <petkan@mip-labs.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>

security/integrity/ima/ima_policy.c

@@ -300,13 +300,12 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 		return IMA_MMAP_APPRAISE;
 	case BPRM_CHECK:
 		return IMA_BPRM_APPRAISE;
-	case MODULE_CHECK:
-		return IMA_MODULE_APPRAISE;
-	case FIRMWARE_CHECK:
-		return IMA_FIRMWARE_APPRAISE;
 	case FILE_CHECK:
-	default:
+	case POST_SETATTR:
 		return IMA_FILE_APPRAISE;
+	case MODULE_CHECK ... MAX_CHECK - 1:
+	default:
+		return IMA_READ_APPRAISE;
 	}
 }