Re: [PATCH 2/2] file capabilities: turn on by default

From: Serge E. Hallyn
Date: Mon Sep 22 2008 - 15:57:22 EST


Quoting Randy Dunlap (randy.dunlap@xxxxxxxxxx):
> On Mon, 22 Sep 2008 13:49:01 -0500 Serge E. Hallyn wrote:
>
> >
> > Now that file capabilities can be turned off at boot, go ahead
> > and compile them into the kernel by default by making
> > CONFIG_SECURITY_FILE_CAPABILITIES=y the default.
>
> Hi,
>
> How much code does this add to everyone's kernel?

Here are the sizes I get with Linus' plain tree and patched
with both of these patches:

master with file capabilities: 6241626
master w/o file capabilities: 6241595

patched with file capabilities: 6241782
patched w/o file capabilities: 6241595

So actually I don't like the added size.

> > Note that the boot flag no_file_caps must be specified to turn
> > file capabilities off, as by default they are on. So the
> > default behavior is in fact changed.
>
> If most people want this enable, using 'no_file_caps' makes
> some sense. OTOH, if most people don't want/use it, then
> having a 'file_caps_on' option would make more sense.
>
> Do you have any (unbiased :) ideas about this?

I'll sit this one out I guess :)

> Thanks.
>
> > Signed-off-by: Serge Hallyn <serue@xxxxxxxxxx>
> > Acked-by: Andrew G. Morgan <morgan@xxxxxxxxxx>
> > ---
> > security/Kconfig | 7 +++++--
> > 1 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/security/Kconfig b/security/Kconfig
> > index 5592939..6fbb233 100644
> > --- a/security/Kconfig
> > +++ b/security/Kconfig
> > @@ -75,12 +75,15 @@ config SECURITY_NETWORK_XFRM
> >
> > config SECURITY_FILE_CAPABILITIES
> > bool "File POSIX Capabilities"
> > - default n
> > + default y
> > help
> > This enables filesystem capabilities, allowing you to give
> > binaries a subset of root's powers without using setuid 0.
> >
> > - If in doubt, answer N.
> > + You can still boot with the no_file_caps option to disable
> > + file capabilities.
> > +
> > + If in doubt, answer Y.
> >
> > config SECURITY_ROOTPLUG
> > bool "Root Plug Support"
>
>
> ---
> ~Randy
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