diff options
| -rw-r--r-- | kernel/sys.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index 7ef7f6054c28..0b6ec0e7936f 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1372,18 +1372,29 @@ asmlinkage long sys_getsid(pid_t pid) asmlinkage long sys_setsid(void) { struct task_struct *group_leader = current->group_leader; - struct pid *pid; + pid_t session; int err = -EPERM; mutex_lock(&tty_mutex); write_lock_irq(&tasklist_lock); - pid = find_pid(PIDTYPE_PGID, group_leader->pid); - if (pid) + /* 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. + * + * 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. + */ + if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session)) goto out; group_leader->signal->leader = 1; - __set_special_pids(group_leader->pid, group_leader->pid); + __set_special_pids(session, session); group_leader->signal->tty = NULL; group_leader->signal->tty_old_pgrp = 0; err = process_group(group_leader); |