Messages in this thread Patch in this message | | | Date | Mon, 26 Nov 2007 17:25:53 +0300 | From | Oleg Nesterov <> | Subject | [PATCH 1/3] fix setsid() for sub-namespace /sbin/init |
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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>
--- 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; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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