diff options
| -rw-r--r-- | fs/proc/base.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 3ce5ae9e3d2..917f338a673 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -237,20 +237,19 @@ struct mm_struct *mm_for_maps(struct task_struct *task) struct mm_struct *mm = get_task_mm(task); if (!mm) return NULL; + if (mm != current->mm) { + /* + * task->mm can be changed before security check, + * in that case we must notice the change after. + */ + if (!ptrace_may_access(task, PTRACE_MODE_READ) || + mm != task->mm) { + mmput(mm); + return NULL; + } + } down_read(&mm->mmap_sem); - task_lock(task); - if (task->mm != mm) - goto out; - if (task->mm != current->mm && - __ptrace_may_access(task, PTRACE_MODE_READ) < 0) - goto out; - task_unlock(task); return mm; -out: - task_unlock(task); - up_read(&mm->mmap_sem); - mmput(mm); - return NULL; } static int proc_pid_cmdline(struct task_struct *task, char * buffer) |