Subject: [merged] pidns-fix-vfork-after-unshareclone_newpid.patch removed from -mm tree To: oleg@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,luto@xxxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,walters@xxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 12 Sep 2013 12:41:09 -0700 The patch titled Subject: pidns: fix vfork() after unshare(CLONE_NEWPID) has been removed from the -mm tree. Its filename was pidns-fix-vfork-after-unshareclone_newpid.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: pidns: fix vfork() after unshare(CLONE_NEWPID) 8382fcac ("pidns: Outlaw thread creation after unshare(CLONE_NEWPID)") nacks CLONE_VM if the forking process unshared pid_ns, this obviously breaks vfork: int main(void) { assert(unshare(CLONE_NEWUSER | CLONE_NEWPID) == 0); assert(vfork() >= 0); _exit(0); return 0; } fails without this patch. Change this check to use CLONE_SIGHAND instead. This also forbids CLONE_THREAD automatically, and this is what the comment implies. We could probably even drop CLONE_SIGHAND and use CLONE_THREAD, but it would be safer to not do this. The current check denies CLONE_SIGHAND implicitely and there is no reason to change this. Eric said "CLONE_SIGHAND is fine. CLONE_THREAD would be even better. Having shared signal handling between two different pid namespaces is the case that we are fundamentally guarding against." Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Reported-by: Colin Walters <walters@xxxxxxxxxx> Acked-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Reviewed-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/fork.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff -puN kernel/fork.c~pidns-fix-vfork-after-unshareclone_newpid kernel/fork.c --- a/kernel/fork.c~pidns-fix-vfork-after-unshareclone_newpid +++ a/kernel/fork.c @@ -1173,10 +1173,11 @@ static struct task_struct *copy_process( return ERR_PTR(-EINVAL); /* - * If the new process will be in a different pid namespace - * don't allow the creation of threads. + * If the new process will be in a different pid namespace don't + * allow it to share a thread group or signal handlers with the + * forking task. */ - if ((clone_flags & (CLONE_VM|CLONE_NEWPID)) && + if ((clone_flags & (CLONE_SIGHAND | CLONE_NEWPID)) && (task_active_pid_ns(current) != current->nsproxy->pid_ns_for_children)) return ERR_PTR(-EINVAL); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are origin.patch anon_inodefs-forbid-open-via-proc.patch autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch signals-eventpoll-set-saved_sigmask-at-the-start.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html