apparmor: move to per loaddata files, instead of replicating in profiles

The loaddata sets cover more than just a single profile and should
be tracked at the ns level. Move the load data files under the namespace
and reference the files from the profiles via a symlink.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

3 files changed, 72 insertions, 4 deletions

diff --git a/security/apparmor/include/apparmorfs.h b/security/apparmor/include/apparmorfs.h
index 120a798b5bb0..0b6d32b3f05e 100644
--- a/security/apparmor/include/apparmorfs.h
+++ b/security/apparmor/include/apparmorfs.h
@@ -106,6 +106,7 @@ enum aafs_prof_type {
 #define prof_dir(X) ((X)->dents[AAFS_PROF_DIR])
 #define prof_child_dir(X) ((X)->dents[AAFS_PROF_PROFS])
 
+void __aa_bump_ns_revision(struct aa_ns *ns);
 void __aa_fs_profile_rmdir(struct aa_profile *profile);
 void __aa_fs_profile_migrate_dents(struct aa_profile *old,
 				   struct aa_profile *new);
@@ -114,4 +115,8 @@ void __aa_fs_ns_rmdir(struct aa_ns *ns);
 int __aa_fs_ns_mkdir(struct aa_ns *ns, struct dentry *parent,
 		     const char *name);
 
+struct aa_loaddata;
+void __aa_fs_remove_rawdata(struct aa_loaddata *rawdata);
+int __aa_fs_create_rawdata(struct aa_ns *ns, struct aa_loaddata *rawdata);
+
 #endif /* __AA_APPARMORFS_H */
diff --git a/security/apparmor/include/policy_ns.h b/security/apparmor/include/policy_ns.h
index 89cffddd7e75..d7a07ac96168 100644
--- a/security/apparmor/include/policy_ns.h
+++ b/security/apparmor/include/policy_ns.h
@@ -68,6 +68,9 @@ struct aa_ns {
 	atomic_t uniq_null;
 	long uniq_id;
 	int level;
+	long revision;
+
+	struct list_head rawdata_list;
 
 	struct dentry *dents[AAFS_NS_SIZEOF];
 };
diff --git a/security/apparmor/include/policy_unpack.h b/security/apparmor/include/policy_unpack.h
index 4c1319eebc42..be6cd69ac319 100644
--- a/security/apparmor/include/policy_unpack.h
+++ b/security/apparmor/include/policy_unpack.h
@@ -17,6 +17,8 @@
 
 #include <linux/list.h>
 #include <linux/kref.h>
+#include <linux/dcache.h>
+#include <linux/workqueue.h>
 
 struct aa_load_ent {
 	struct list_head list;
@@ -36,26 +38,84 @@ struct aa_load_ent *aa_load_ent_alloc(void);
 #define PACKED_MODE_KILL	2
 #define PACKED_MODE_UNCONFINED	3
 
-/* struct aa_loaddata - buffer of policy load data set */
+struct aa_ns;
+
+enum {
+	AAFS_LOADDATA_ABI = 0,
+	AAFS_LOADDATA_REVISION,
+	AAFS_LOADDATA_HASH,
+	AAFS_LOADDATA_DATA,
+	AAFS_LOADDATA_DIR,		/* must be last actual entry */
+	AAFS_LOADDATA_NDENTS		/* count of entries */
+};
+
+/*
+ * struct aa_loaddata - buffer of policy raw_data set
+ *
+ * there is no loaddata ref for being on ns list, nor a ref from
+ * d_inode(@dentry) when grab a ref from these, @ns->lock must be held
+ * && __aa_get_loaddata() needs to be used, and the return value
+ * checked, if NULL the loaddata is already being reaped and should be
+ * considered dead.
+ */
 struct aa_loaddata {
 	struct kref count;
+	struct list_head list;
+	struct work_struct work;
+	struct dentry *dents[AAFS_LOADDATA_NDENTS];
+	struct aa_ns *ns;
+	char *name;
 	size_t size;
+	long revision;			/* the ns policy revision this caused */
 	int abi;
 	unsigned char *hash;
+
 	char data[];
 };
 
 int aa_unpack(struct aa_loaddata *udata, struct list_head *lh, const char **ns);
 
+/**
+ * __aa_get_loaddata - get a reference count to uncounted data reference
+ * @data: reference to get a count on
+ *
+ * Returns: pointer to reference OR NULL if race is lost and reference is
+ *          being repeated.
+ * Requires: @data->ns->lock held, and the return code MUST be checked
+ *
+ * Use only from inode->i_private and @data->list found references
+ */
+static inline struct aa_loaddata *
+__aa_get_loaddata(struct aa_loaddata *data)
+{
+	if (data && kref_get_unless_zero(&(data->count)))
+		return data;
+
+	return NULL;
+}
+
+/**
+ * aa_get_loaddata - get a reference count from a counted data reference
+ * @data: reference to get a count on
+ *
+ * Returns: point to reference
+ * Requires: @data to have a valid reference count on it. It is a bug
+ *           if the race to reap can be encountered when it is used.
+ */
 static inline struct aa_loaddata *
 aa_get_loaddata(struct aa_loaddata *data)
 {
-	if (data)
-		kref_get(&(data->count));
-	return data;
+	struct aa_loaddata *tmp = __aa_get_loaddata(data);
+
+	AA_BUG(data && !tmp);
+
+	return tmp;
 }
 
+void __aa_loaddata_update(struct aa_loaddata *data, long revision);
+bool aa_rawdata_eq(struct aa_loaddata *l, struct aa_loaddata *r);
 void aa_loaddata_kref(struct kref *kref);
+struct aa_loaddata *aa_loaddata_alloc(size_t size);
 static inline void aa_put_loaddata(struct aa_loaddata *data)
 {
 	if (data)