apparmor: change how profile replacement update is done

[deliverable/linux.git] / security / apparmor / include / policy.h

diff --git a/security/apparmor/include/policy.h b/security/apparmor/include/policy.h
index 82487a853353f8538d9efe948ec790e84fae9f92..e9f2baf4467ed47b2eb724850c0cb359f5af2c7b 100644 (file)
--- a/security/apparmor/include/policy.h
+++ b/security/apparmor/include/policy.h
@@ -42,6 +42,8 @@ extern const char *const profile_mode_names[];
 
 #define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)
 
+#define PROFILE_INVALID(_profile) ((_profile)->flags & PFLAG_INVALID)
+
 #define on_list_rcu(X) (!list_empty(X) && (X)->prev != LIST_POISON2)
 
 /*
@@ -65,6 +67,7 @@ enum profile_flags {
        PFLAG_USER_DEFINED = 0x20,      /* user based profile - lower privs */
        PFLAG_NO_LIST_REF = 0x40,       /* list doesn't keep profile ref */
        PFLAG_OLD_NULL_TRANS = 0x100,   /* use // as the null transition */
+       PFLAG_INVALID = 0x200,          /* profile replaced/removed */
 
        /* These flags must correspond with PATH_flags */
        PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
@@ -146,6 +149,12 @@ struct aa_policydb {
 
 };
 
+struct aa_replacedby {
+       struct kref count;
+       struct aa_profile __rcu *profile;
+};
+
+
 /* struct aa_profile - basic confinement data
  * @base - base components of the profile (name, refcount, lists, lock ...)
  * @parent: parent of profile
@@ -169,8 +178,7 @@ struct aa_policydb {
  * used to determine profile attachment against unconfined tasks.  All other
  * attachments are determined by profile X transition rules.
  *
- * The @replacedby field is write protected by the profile lock.  Reads
- * are assumed to be atomic.
+ * The @replacedby struct is write protected by the profile lock.
  *
  * Profiles have a hierarchy where hats and children profiles keep
  * a reference to their parent.
@@ -184,14 +192,14 @@ struct aa_profile {
        struct aa_profile __rcu *parent;
 
        struct aa_namespace *ns;
-       struct aa_profile *replacedby;
+       struct aa_replacedby *replacedby;
        const char *rename;
 
        struct aa_dfa *xmatch;
        int xmatch_len;
        enum audit_mode audit;
        enum profile_mode mode;
-       u32 flags;
+       long flags;
        u32 path_flags;
        int size;
 
@@ -250,6 +258,7 @@ static inline void aa_put_namespace(struct aa_namespace *ns)
                kref_put(&ns->base.count, aa_free_namespace_kref);
 }
 
+void aa_free_replacedby_kref(struct kref *kref);
 struct aa_profile *aa_alloc_profile(const char *name);
 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
 void aa_free_profile_kref(struct kref *kref);
@@ -265,24 +274,6 @@ ssize_t aa_remove_profiles(char *name, size_t size);
 
 #define unconfined(X) ((X)->flags & PFLAG_UNCONFINED)
 
-/**
- * aa_newest_version - find the newest version of @profile
- * @profile: the profile to check for newer versions of (NOT NULL)
- *
- * Returns: newest version of @profile, if @profile is the newest version
- *          return @profile.
- *
- * NOTE: the profile returned is not refcounted, The refcount on @profile
- * must be held until the caller decides what to do with the returned newest
- * version.
- */
-static inline struct aa_profile *aa_newest_version(struct aa_profile *profile)
-{
-       while (profile->replacedby)
-               profile = profile->replacedby;
-
-       return profile;
-}
 
 /**
  * aa_get_profile - increment refcount on profile @p
@@ -334,6 +325,25 @@ static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
        return c;
 }
 
+/**
+ * aa_get_newest_profile - find the newest version of @profile
+ * @profile: the profile to check for newer versions of
+ *
+ * Returns: refcounted newest version of @profile taking into account
+ *          replacement, renames and removals
+ *          return @profile.
+ */
+static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
+{
+       if (!p)
+               return NULL;
+
+       if (PROFILE_INVALID(p))
+               return aa_get_profile_rcu(&p->replacedby->profile);
+
+       return aa_get_profile(p);
+}
+
 /**
  * aa_put_profile - decrement refcount on profile @p
  * @p: profile  (MAYBE NULL)
@@ -344,6 +354,30 @@ static inline void aa_put_profile(struct aa_profile *p)
                kref_put(&p->base.count, aa_free_profile_kref);
 }
 
+static inline struct aa_replacedby *aa_get_replacedby(struct aa_replacedby *p)
+{
+       if (p)
+               kref_get(&(p->count));
+
+       return p;
+}
+
+static inline void aa_put_replacedby(struct aa_replacedby *p)
+{
+       if (p)
+               kref_put(&p->count, aa_free_replacedby_kref);
+}
+
+/* requires profile list write lock held */
+static inline void __aa_update_replacedby(struct aa_profile *orig,
+                                         struct aa_profile *new)
+{
+       struct aa_profile *tmp = rcu_dereference(orig->replacedby->profile);
+       rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
+       orig->flags |= PFLAG_INVALID;
+       aa_put_profile(tmp);
+}
+
 static inline int AUDIT_MODE(struct aa_profile *profile)
 {
        if (aa_g_audit != AUDIT_NORMAL)