apparmor: isolate policy backwards compatibility to its own file

The details of mapping old policy into newer policy formats clutters
up the unpack code and makes it possible to accidentally use old
mappings in code, so isolate the mapping code into its own file.

This will become more important when the dfa remapping code lands,
as it will greatly expand the compat code base.

Signed-off-by: John Johansen <john.johansen@canonical.com>

2 files changed, 34 insertions, 0 deletions

diff --git a/security/apparmor/include/policy_compat.h b/security/apparmor/include/policy_compat.h
new file mode 100644
index 000000000000..af0e174332df
--- /dev/null
+++ b/security/apparmor/include/policy_compat.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * AppArmor security module
+ *
+ * Code to provide backwards compatibility with older policy versions,
+ * by converting/mapping older policy formats into the newer internal
+ * formats.
+ *
+ * Copyright 2022 Canonical Ltd.
+ */
+
+#ifndef __POLICY_COMPAT_H
+#define __POLICY_COMPAT_H
+
+#include "policy.h"
+
+#define K_ABI_MASK 0x3ff
+#define FORCE_COMPLAIN_FLAG 0x800
+#define VERSION_LT(X, Y) (((X) & K_ABI_MASK) < ((Y) & K_ABI_MASK))
+#define VERSION_LE(X, Y) (((X) & K_ABI_MASK) <= ((Y) & K_ABI_MASK))
+#define VERSION_GT(X, Y) (((X) & K_ABI_MASK) > ((Y) & K_ABI_MASK))
+
+#define v5	5	/* base version */
+#define v6	6	/* per entry policydb mediation check */
+#define v7	7
+#define v8	8	/* full network masking */
+#define v9	9	/* xbits are used as permission bits in policydb */
+
+int aa_compat_map_xmatch(struct aa_policydb *policy);
+int aa_compat_map_policy(struct aa_policydb *policy, u32 version);
+int aa_compat_map_file(struct aa_policydb *policy);
+
+#endif /* __POLICY_COMPAT_H */
diff --git a/security/apparmor/include/policy_unpack.h b/security/apparmor/include/policy_unpack.h
index eb5f7d7f132b..cdfbc8a54a9d 100644
--- a/security/apparmor/include/policy_unpack.h
+++ b/security/apparmor/include/policy_unpack.h
@@ -16,6 +16,7 @@
 #include <linux/dcache.h>
 #include <linux/workqueue.h>
 
+
 struct aa_load_ent {
 	struct list_head list;
 	struct aa_profile *new;