diff options
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 33 |
1 files changed, 18 insertions, 15 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 3326bbf9ab9..6f742f6658a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -234,23 +234,20 @@ static int check_mem_permission(struct task_struct *task) struct mm_struct *mm_for_maps(struct task_struct *task) { - struct mm_struct *mm = get_task_mm(task); - if (!mm) + struct mm_struct *mm; + + if (mutex_lock_killable(&task->cred_guard_mutex)) 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); + + mm = get_task_mm(task); + if (mm && mm != current->mm && + !ptrace_may_access(task, PTRACE_MODE_READ)) { + mmput(mm); + mm = NULL; + } + mutex_unlock(&task->cred_guard_mutex); + 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) @@ -2128,9 +2125,15 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, if (copy_from_user(page, buf, count)) goto out_free; + /* Guard against adverse ptrace interaction */ + length = mutex_lock_interruptible(&task->cred_guard_mutex); + if (length < 0) + goto out_free; + length = security_setprocattr(task, (char*)file->f_path.dentry->d_name.name, (void*)page, count); + mutex_unlock(&task->cred_guard_mutex); out_free: free_page((unsigned long) page); out: |