From 5167246a8ad617df55717c2d901da5e2aedffcfa Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 11 Sep 2013 14:19:40 -0700 Subject: [PATCH] pidns: kill the unnecessary CLONE_NEWPID in copy_process() Commit 8382fcac1b81 ("pidns: Outlaw thread creation after unshare(CLONE_NEWPID)") nacks CLONE_NEWPID if the forking process unshared pid_ns. This is correct but unnecessary, copy_pid_ns() does the same check. Remove the CLONE_NEWPID check to cleanup the code and prepare for the next change. Test-case: static int child(void *arg) { return 0; } static char stack[16 * 1024]; int main(void) { pid_t pid; assert(unshare(CLONE_NEWUSER | CLONE_NEWPID) == 0); pid = clone(child, stack + sizeof(stack) / 2, CLONE_NEWPID | SIGCHLD, NULL); assert(pid < 0 && errno == EINVAL); return 0; } clone(CLONE_NEWPID) correctly fails with or without this change. Signed-off-by: Oleg Nesterov Acked-by: Andy Lutomirski Cc: "Eric W. Biederman" Cc: Colin Walters Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 3561391ca450..68d508f2bfba 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1177,9 +1177,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, * allow it to share a thread group or signal handlers with the * forking task. */ - if ((clone_flags & (CLONE_SIGHAND | CLONE_NEWPID)) && - (task_active_pid_ns(current) != - current->nsproxy->pid_ns_for_children)) + if ((clone_flags & CLONE_SIGHAND) && (task_active_pid_ns(current) != + current->nsproxy->pid_ns_for_children)) return ERR_PTR(-EINVAL); retval = security_task_create(clone_flags); -- 2.20.1