2009-07-28 16:41:33

by Sukadev Bhattiprolu

Subject: [PATCH] Deny CLONE_PARENT|CLONE_NEWPID combination

Deny CLONE_PARENT|CLONE_NEWPID combination.

CLONE_PARENT was used to implement an older threading model. For consistency
with the CLONE_THREAD check in copy_pid_ns(), disable CLONE_PARENT and
CLONE_SIGHAND with CLONE_NEWPID, at least until the required semantics of
the pid namespaces are clear.

Changelog[v3]:
Remove CLONE_SIGHAND and for now only fail CLONE_NEWPID|CLONE_PARENT.
Changelog[v2]:
[Eric Biederman] Disable CLONE_SIGHAND also ?

Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
---
kernel/pid_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-mmotm/kernel/pid_namespace.c
===================================================================
--- linux-mmotm.orig/kernel/pid_namespace.c 2009-07-16 10:03:01.000000000 -0700
+++ linux-mmotm/kernel/pid_namespace.c 2009-07-16 11:37:24.000000000 -0700
@@ -118,7 +118,7 @@
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
- if (flags & CLONE_THREAD)
+ if (flags & (CLONE_THREAD|CLONE_PARENT))
return ERR_PTR(-EINVAL);
return create_pid_namespace(old_ns);
}

2009-07-28 18:06:15

by Serge E. Hallyn

Subject: Re: [PATCH] Deny CLONE_PARENT|CLONE_NEWPID combination

Quoting Sukadev Bhattiprolu ([email protected]):
>
> Deny CLONE_PARENT|CLONE_NEWPID combination.
>
> CLONE_PARENT was used to implement an older threading model. For consistency
> with the CLONE_THREAD check in copy_pid_ns(), disable CLONE_PARENT and
> CLONE_SIGHAND with CLONE_NEWPID, at least until the required semantics of
> the pid namespaces are clear.
>
> Changelog[v3]:
> Remove CLONE_SIGHAND and for now only fail CLONE_NEWPID|CLONE_PARENT.

(FWIW your patch description does not reflect this...)

> Changelog[v2]:
> [Eric Biederman] Disable CLONE_SIGHAND also ?
>
> Signed-off-by: Sukadev Bhattiprolu <[email protected]>
> Acked-by: Roland McGrath <[email protected]>
> Acked-by: Serge Hallyn <[email protected]>
> ---
> kernel/pid_namespace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-mmotm/kernel/pid_namespace.c
> ===================================================================
> --- linux-mmotm.orig/kernel/pid_namespace.c 2009-07-16 10:03:01.000000000 -0700
> +++ linux-mmotm/kernel/pid_namespace.c 2009-07-16 11:37:24.000000000 -0700
> @@ -118,7 +118,7 @@
> {
> if (!(flags & CLONE_NEWPID))
> return get_pid_ns(old_ns);
> - if (flags & CLONE_THREAD)
> + if (flags & (CLONE_THREAD|CLONE_PARENT))
> return ERR_PTR(-EINVAL);
> return create_pid_namespace(old_ns);
> }

2009-07-28 19:04:26

by Sukadev Bhattiprolu

Subject: Re: [PATCH] Deny CLONE_PARENT|CLONE_NEWPID combination

Serge E. Hallyn [[email protected]] wrote:
| Quoting Sukadev Bhattiprolu ([email protected]):
| >
| > Deny CLONE_PARENT|CLONE_NEWPID combination.
| >
| > CLONE_PARENT was used to implement an older threading model. For consistency
| > with the CLONE_THREAD check in copy_pid_ns(), disable CLONE_PARENT and
| > CLONE_SIGHAND with CLONE_NEWPID, at least until the required semantics of
| > the pid namespaces are clear.
| >
| > Changelog[v3]:
| > Remove CLONE_SIGHAND and for now only fail CLONE_NEWPID|CLONE_PARENT.
|
| (FWIW your patch description does not reflect this...)

You are right. Here is the patch with updated description.
---

Deny CLONE_PARENT|CLONE_NEWPID|CLONE_SIGHAND combination.

CLONE_PARENT was used to implement an older threading model. For consistency
with the CLONE_THREAD check in copy_pid_ns(), disable CLONE_PARENT with
CLONE_NEWPID, at least until the required semantics of pid namespaces are
clear.

Changelog[v3]:
Remove CLONE_SIGHAND and for now only fail CLONE_NEWPID|CLONE_PARENT.
Changelog[v2]:
[Eric Biederman] Disable CLONE_SIGHAND also ?

Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
---
kernel/pid_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-mmotm/kernel/pid_namespace.c
===================================================================
--- linux-mmotm.orig/kernel/pid_namespace.c 2009-07-16 10:03:01.000000000 -0700
+++ linux-mmotm/kernel/pid_namespace.c 2009-07-16 11:37:24.000000000 -0700
@@ -118,7 +118,7 @@
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
- if (flags & CLONE_THREAD)
+ if (flags & (CLONE_THREAD|CLONE_PARENT))
return ERR_PTR(-EINVAL);
return create_pid_namespace(old_ns);
}