2017-11-10 02:57:54

by James Morris

[permalink] [raw]
Subject: Re: [PATCH RFC v3 6/7] proc: support new 'pids=all|ptraceable' mount option

On Thu, 9 Nov 2017, Djalal Harouni wrote:

> This patch introduces the new 'pids' mount option, as it was discussed
> and suggested by Andy Lutomirski [1].
>
> * If 'pids=' is passed without 'newinstance' then it has no effect.
>
> * If 'newinstance,pids=all' then all processes will be shown in proc.
>
> * If 'newinstance,pids=ptraceable' then only ptraceable processes will be
> shown.
>
> * 'pids=' takes precendence over 'hidepid=' since 'hidepid=' can be
> ignored if "gid=" was set and caller has the "gid=" set in its groups.
> We want to guarantee that LSM have a security path there that can not
> be disabled with "gid=".
>
> This allows to support lightweight sandboxes in Embedded Linux.
>
> Later Yama LSM can be updated to check that processes are able only
> able to see their children inside /proc/, allowing to support more tight
> cases.
>
> [1] https://lkml.org/lkml/2017/4/26/646
>
> Cc: Kees Cook <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Suggested-by: Andy Lutomirski <[email protected]>
> Signed-off-by: Alexey Gladkov <[email protected]>
> Signed-off-by: Djalal Harouni <[email protected]>


Reviewed-by: James Morris <[email protected]>


--
James Morris
<[email protected]>


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