From 123be07b0b399670a7cc3d82fef0cb4f93ef885c Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Wed, 23 Sep 2009 15:57:20 -0700 Subject: fork(): disable CLONE_PARENT for init When global or container-init processes use CLONE_PARENT, they create a multi-rooted process tree. Besides siblings of global init remain as zombies on exit since they are not reaped by their parent (swapper). So prevent global and container-inits from creating siblings. Signed-off-by: Sukadev Bhattiprolu Acked-by: Eric W. Biederman Acked-by: Roland McGrath Cc: Oren Laadan Cc: Oleg Nesterov Cc: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 51ad0b0b7266..b51fd2ccb2f1 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -979,6 +979,16 @@ static struct task_struct *copy_process(unsigned long clone_flags, if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) return ERR_PTR(-EINVAL); + /* + * Siblings of global init remain as zombies on exit since they are + * not reaped by their parent (swapper). To solve this and to avoid + * multi-rooted process trees, prevent global and container-inits + * from creating siblings. + */ + if ((clone_flags & CLONE_PARENT) && + current->signal->flags & SIGNAL_UNKILLABLE) + return ERR_PTR(-EINVAL); + retval = security_task_create(clone_flags); if (retval) goto fork_out; -- cgit v1.2.3