Messages in this thread | | | Date | Mon, 26 Nov 2007 18:00:36 +0300 | From | Pavel Emelyanov <> | Subject | Re: [PATCH 1/3] fix setsid() for sub-namespace /sbin/init |
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Oleg Nesterov wrote: > sys_setsid() still deals with pid_t's from the global namespace. This means > that the "session > 1" check can't help for sub-namespace init, setsid() can't > succeed because copy_process(CLONE_NEWPID) populates PIDTYPE_PGID/SID links. > > Remove the usage of task_struct->pid and convert the code to use "struct pid". > This also simplifies and speedups the code, saves one find_pid(). > > Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
> --- PT/kernel/sys.c~1_setsid 2007-11-26 15:52:15.000000000 +0300 > +++ PT/kernel/sys.c 2007-11-26 16:10:43.000000000 +0300 > @@ -1045,35 +1045,33 @@ asmlinkage long sys_getsid(pid_t pid) > asmlinkage long sys_setsid(void) > { > struct task_struct *group_leader = current->group_leader; > - pid_t session; > + struct pid *sid = task_pid(group_leader); > + pid_t session = pid_vnr(sid); > int err = -EPERM; > > write_lock_irq(&tasklist_lock); > - > /* Fail if I am already a session leader */ > if (group_leader->signal->leader) > goto out; > > - session = group_leader->pid; > - /* Fail if a process group id already exists that equals the > - * proposed session id. > + /* Fail if a process group id already exists that equals the proposed > + * session id. > * > - * Don't check if session id == 1 because kernel threads use this > - * session id and so the check will always fail and make it so > - * init cannot successfully call setsid. > + * Don't check if session == 1 because kernel threads and CLONE_NEWPID > + * tasks use this session id and so the check will always fail and make > + * it so init cannot successfully call setsid. > */ > - if (session > 1 && find_task_by_pid_type_ns(PIDTYPE_PGID, > - session, &init_pid_ns)) > + if (session != 1 && pid_task(sid, PIDTYPE_PGID)) > goto out; > > group_leader->signal->leader = 1; > - __set_special_pids(session, session); > + __set_special_pids(pid_nr(sid), pid_nr(sid)); > > spin_lock(&group_leader->sighand->siglock); > group_leader->signal->tty = NULL; > spin_unlock(&group_leader->sighand->siglock); > > - err = task_pgrp_vnr(group_leader); > + err = session; > out: > write_unlock_irq(&tasklist_lock); > return err; > >
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