diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2009-04-02 16:58:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:05:02 -0700 |
| commit | 2ae448efc87df6d328f5835969076c7f9fce59c3 (patch) | |
| tree | f110b43fa7c6b3c80f9b18a8e4fef728ed57f448 | |
| parent | 6dda81f4384b94930826eded254d8c16f89a9248 (diff) | |
pids: improve get_task_pid() to fix the unsafe sys_wait4()->task_pgrp()
sys_wait4() does get_pid(task_pgrp(current)), this is not safe. We can
add rcu lock/unlock around, but we already have get_task_pid() which can
be improved to handle the special pids in more reliable manner.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/exit.c | 2 | ||||
| -rw-r--r-- | kernel/pid.c | 2 |
2 files changed, 3 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 029415d9f82e..384f09caf2ef 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1737,7 +1737,7 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, pid = find_get_pid(-upid); } else if (upid == 0) { type = PIDTYPE_PGID; - pid = get_pid(task_pgrp(current)); + pid = get_task_pid(current, PIDTYPE_PGID); } else /* upid > 0 */ { type = PIDTYPE_PID; pid = find_get_pid(upid); diff --git a/kernel/pid.c b/kernel/pid.c index 1b3586fe753a..6628abcc520e 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -403,6 +403,8 @@ struct pid *get_task_pid(struct task_struct *task, enum pid_type type) { struct pid *pid; rcu_read_lock(); + if (type != PIDTYPE_PID) + task = task->group_leader; pid = get_pid(task->pids[type].pid); rcu_read_unlock(); return pid; |