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authorOleg Nesterov <oleg@tv-sign.ru>2008-02-08 04:19:09 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 09:22:27 -0800
commite4cc0a9c876d4d4eadaef97a2bff4a199946d202 (patch)
treee25406d84ce842c54e3ac5438e4bcee32a75a964 /kernel/sys.c
parent4e021306cff4277764a42065214fc73f2d26be4b (diff)
downloadlwn-e4cc0a9c876d4d4eadaef97a2bff4a199946d202.tar.gz
lwn-e4cc0a9c876d4d4eadaef97a2bff4a199946d202.zip
fix setsid() for sub-namespace /sbin/init
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> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sys.c')
-rw-r--r--kernel/sys.c22
1 files changed, 10 insertions, 12 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 42136dd453d1..e13bc518b444 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -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;