tracehook: tracehook_tracer_task

This adds the tracehook_tracer_task() hook to consolidate all forms of
"Who is using ptrace on me?" logic.  This is used for "TracerPid:" in
/proc and for permission checks.  We also clean up the selinux code the
called an identical accessor.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 19 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 63f131fc42e4..3481cde5bf15 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -25,7 +25,7 @@
 
 #include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/ptrace.h>
+#include <linux/tracehook.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/security.h>
@@ -1971,22 +1971,6 @@ static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
         return __vm_enough_memory(mm, pages, cap_sys_admin);
 }
 
-/**
- * task_tracer_task - return the task that is tracing the given task
- * @task:               task to consider
- *
- * Returns NULL if noone is tracing @task, or the &struct task_struct
- * pointer to its tracer.
- *
- * Must be called under rcu_read_lock().
- */
-static struct task_struct *task_tracer_task(struct task_struct *task)
-{
-        if (task->ptrace & PT_PTRACED)
-                return rcu_dereference(task->parent);
-        return NULL;
-}
-
 /* binprm security operations */
 
 static int selinux_bprm_alloc_security(struct linux_binprm *bprm)
@@ -2238,7 +2222,7 @@ static void selinux_bprm_apply_creds(struct linux_binprm *bprm, int unsafe)
                         u32 ptsid = 0;
 
                         rcu_read_lock();
-                        tracer = task_tracer_task(current);
+                        tracer = tracehook_tracer_task(current);
                         if (likely(tracer != NULL)) {
                                 sec = tracer->security;
                                 ptsid = sec->sid;
@@ -5247,7 +5231,7 @@ static int selinux_setprocattr(struct task_struct *p,
                    Otherwise, leave SID unchanged and fail. */
                 task_lock(p);
                 rcu_read_lock();
-                tracer = task_tracer_task(p);
+                tracer = tracehook_tracer_task(p);
                 if (tracer != NULL) {
                         struct task_security_struct *ptsec = tracer->security;
                         u32 ptsid = ptsec->sid;