apparmor: add utility function to get an arbitrary tasks profile.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Steve Beattie <sbeattie@ubuntu.com>

4 files changed, 49 insertions, 32 deletions

diff --git a/security/apparmor/context.c b/security/apparmor/context.c
index 8a9b5027c813..611e6ce70b03 100644
--- a/security/apparmor/context.c
+++ b/security/apparmor/context.c
@@ -69,6 +69,23 @@ void aa_dup_task_context(struct aa_task_cxt *new, const struct aa_task_cxt *old)
 }
 
 /**
+ * aa_get_task_profile - Get another task's profile
+ * @task: task to query  (NOT NULL)
+ *
+ * Returns: counted reference to @task's profile
+ */
+struct aa_profile *aa_get_task_profile(struct task_struct *task)
+{
+        struct aa_profile *p;
+
+        rcu_read_lock();
+        p = aa_get_profile(__aa_task_profile(task));
+        rcu_read_unlock();
+
+        return p;
+}
+
+/**
  * aa_replace_current_profile - replace the current tasks profiles
  * @profile: new profile  (NOT NULL)
  *
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 7a78e814f0d4..fb47d5b71ea6 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -62,17 +62,14 @@ static int may_change_ptraced_domain(struct task_struct *task,
                                      struct aa_profile *to_profile)
 {
         struct task_struct *tracer;
-        const struct cred *cred = NULL;
         struct aa_profile *tracerp = NULL;
         int error = 0;
 
         rcu_read_lock();
         tracer = ptrace_parent(task);
-        if (tracer) {
+        if (tracer)
                 /* released below */
-                cred = get_task_cred(tracer);
-                tracerp = aa_cred_profile(cred);
-        }
+                tracerp = aa_get_task_profile(tracer);
 
         /* not ptraced */
         if (!tracer || unconfined(tracerp))
@@ -82,8 +79,7 @@ static int may_change_ptraced_domain(struct task_struct *task,
 
 out:
         rcu_read_unlock();
-        if (cred)
-                put_cred(cred);
+        aa_put_profile(tracerp);
 
         return error;
 }
diff --git a/security/apparmor/include/context.h b/security/apparmor/include/context.h
index a9cbee4d9e48..1e9443a58877 100644
--- a/security/apparmor/include/context.h
+++ b/security/apparmor/include/context.h
@@ -80,23 +80,8 @@ int aa_replace_current_profile(struct aa_profile *profile);
 int aa_set_current_onexec(struct aa_profile *profile);
 int aa_set_current_hat(struct aa_profile *profile, u64 token);
 int aa_restore_previous_profile(u64 cookie);
+struct aa_profile *aa_get_task_profile(struct task_struct *task);
 
-/**
- * __aa_task_is_confined - determine if @task has any confinement
- * @task: task to check confinement of  (NOT NULL)
- *
- * If @task != current needs to be called in RCU safe critical section
- */
-static inline bool __aa_task_is_confined(struct task_struct *task)
-{
-        struct aa_task_cxt *cxt = __task_cred(task)->security;
-
-        BUG_ON(!cxt || !cxt->profile);
-        if (unconfined(aa_newest_version(cxt->profile)))
-                return 0;
-
-        return 1;
-}
 
 /**
  * aa_cred_profile - obtain cred's profiles
@@ -114,6 +99,30 @@ static inline struct aa_profile *aa_cred_profile(const struct cred *cred)
 }
 
 /**
+ * __aa_task_profile - retrieve another task's profile
+ * @task: task to query  (NOT NULL)
+ *
+ * Returns: @task's profile without incrementing its ref count
+ *
+ * If @task != current needs to be called in RCU safe critical section
+ */
+static inline struct aa_profile *__aa_task_profile(struct task_struct *task)
+{
+        return aa_cred_profile(__task_cred(task));
+}
+
+/**
+ * __aa_task_is_confined - determine if @task has any confinement
+ * @task: task to check confinement of  (NOT NULL)
+ *
+ * If @task != current needs to be called in RCU safe critical section
+ */
+static inline bool __aa_task_is_confined(struct task_struct *task)
+{
+        return !unconfined(__aa_task_profile(task));
+}
+
+/**
  * __aa_current_profile - find the current tasks confining profile
  *
  * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
index cf1071b14232..c51d2266587e 100644
--- a/security/apparmor/ipc.c
+++ b/security/apparmor/ipc.c
@@ -95,23 +95,18 @@ int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
          *       - tracer profile has CAP_SYS_PTRACE
          */
 
-        struct aa_profile *tracer_p;
-        /* cred released below */
-        const struct cred *cred = get_task_cred(tracer);
+        struct aa_profile *tracer_p = aa_get_task_profile(tracer);
         int error = 0;
-        tracer_p = aa_cred_profile(cred);
 
         if (!unconfined(tracer_p)) {
-                /* lcred released below */
-                const struct cred *lcred = get_task_cred(tracee);
-                struct aa_profile *tracee_p = aa_cred_profile(lcred);
+                struct aa_profile *tracee_p = aa_get_task_profile(tracee);
 
                 error = aa_may_ptrace(tracer, tracer_p, tracee_p, mode);
                 error = aa_audit_ptrace(tracer_p, tracee_p, error);
 
-                put_cred(lcred);
+                aa_put_profile(tracee_p);
         }
-        put_cred(cred);
+        aa_put_profile(tracer_p);
 
         return error;
 }