report errors in /proc/*/*map* sanely, CVE-2011-1020

[linux-flexiantxendom0-natty.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index a86bfd3..e406d56 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -225,15 +225,17 @@ static int check_mem_permission(struct task_struct *task)
 struct mm_struct *mm_for_maps(struct task_struct *task)
 {
        struct mm_struct *mm;
+       int err;
 
-       if (mutex_lock_killable(&task->signal->cred_guard_mutex))
-               return NULL;
+       err =  mutex_lock_killable(&task->signal->cred_guard_mutex);
+       if (err)
+               return ERR_PTR(err);
 
        mm = get_task_mm(task);
        if (mm && mm != current->mm &&
                        !ptrace_may_access(task, PTRACE_MODE_READ)) {
                mmput(mm);
-               mm = NULL;
+               mm = ERR_PTR(-EACCES);
        }
        mutex_unlock(&task->signal->cred_guard_mutex);