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From: David Howells <dhowells@redhat.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: dhowells@redhat.com, ard.biesheuvel@linaro.org,
	matthew.garrett@nebula.com,
	linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] Add the ability to lock down access to the running kernel image
Date: Thu, 25 May 2017 07:53:22 +0100	[thread overview]
Message-ID: <19783.1495695202@warthog.procyon.org.uk> (raw)
In-Reply-To: <80bdc6c9-004b-800f-ffd0-4b5ebf8cdeba@schaufler-ca.com>

Casey Schaufler <casey@schaufler-ca.com> wrote:

> > +#ifdef CONFIG_LOCK_DOWN_KERNEL
> > +extern bool kernel_is_locked_down(void);
> > +#else
> > +static inline bool kernel_is_locked_down(void)
> 
> Should this be a bool or an int? I can imagine that someone is going to want
> various different degrees of lock down for kernels. As an int you could
> return a bitmap indicating which features were locked. This would allow
> additional things to be locked down without changing the interface.

At the moment it makes no difference, since the return value is only ever
passed directly to an if-statement.

Also, do you have an idea as to how is should be divided up?

There aren't so many cases, at least not yet, that they can't be fixed up,
perhaps with a coccinelle script.

David

WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Casey Schaufler <casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
	matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org,
	linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 3/5] Add the ability to lock down access to the running kernel image
Date: Thu, 25 May 2017 07:53:22 +0100	[thread overview]
Message-ID: <19783.1495695202@warthog.procyon.org.uk> (raw)
In-Reply-To: <80bdc6c9-004b-800f-ffd0-4b5ebf8cdeba-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>

Casey Schaufler <casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org> wrote:

> > +#ifdef CONFIG_LOCK_DOWN_KERNEL
> > +extern bool kernel_is_locked_down(void);
> > +#else
> > +static inline bool kernel_is_locked_down(void)
> 
> Should this be a bool or an int? I can imagine that someone is going to want
> various different degrees of lock down for kernels. As an int you could
> return a bitmap indicating which features were locked. This would allow
> additional things to be locked down without changing the interface.

At the moment it makes no difference, since the return value is only ever
passed directly to an if-statement.

Also, do you have an idea as to how is should be divided up?

There aren't so many cases, at least not yet, that they can't be fixed up,
perhaps with a coccinelle script.

David

WARNING: multiple messages have this Message-ID (diff)
From: dhowells@redhat.com (David Howells)
To: linux-security-module@vger.kernel.org
Subject: [PATCH 3/5] Add the ability to lock down access to the running kernel image
Date: Thu, 25 May 2017 07:53:22 +0100	[thread overview]
Message-ID: <19783.1495695202@warthog.procyon.org.uk> (raw)
In-Reply-To: <80bdc6c9-004b-800f-ffd0-4b5ebf8cdeba@schaufler-ca.com>

Casey Schaufler <casey@schaufler-ca.com> wrote:

> > +#ifdef CONFIG_LOCK_DOWN_KERNEL
> > +extern bool kernel_is_locked_down(void);
> > +#else
> > +static inline bool kernel_is_locked_down(void)
> 
> Should this be a bool or an int? I can imagine that someone is going to want
> various different degrees of lock down for kernels. As an int you could
> return a bitmap indicating which features were locked. This would allow
> additional things to be locked down without changing the interface.

At the moment it makes no difference, since the return value is only ever
passed directly to an if-statement.

Also, do you have an idea as to how is should be divided up?

There aren't so many cases, at least not yet, that they can't be fixed up,
perhaps with a coccinelle script.

David
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  parent reply	other threads:[~2017-05-25  6:53 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-24 14:45 [PATCH 0/5] security, efi: Set lockdown if in secure boot mode David Howells
2017-05-24 14:45 ` David Howells
2017-05-24 14:45 ` David Howells
2017-05-24 14:45 ` [PATCH 1/5] efi: Move the x86 secure boot switch to generic code David Howells
2017-05-24 14:45   ` David Howells
2017-05-26  7:59   ` joeyli
2017-05-26  7:59     ` joeyli
2017-05-24 14:45 ` [PATCH 2/5] efi: Add EFI_SECURE_BOOT bit David Howells
2017-05-24 14:45   ` David Howells
2017-05-24 14:45   ` David Howells
2017-05-26  8:06   ` joeyli
2017-05-26  8:06     ` joeyli
2017-05-24 14:45 ` [PATCH 3/5] Add the ability to lock down access to the running kernel image David Howells
2017-05-24 14:45   ` David Howells
2017-05-24 15:36   ` Casey Schaufler
2017-05-24 15:36     ` Casey Schaufler
2017-05-24 15:36     ` Casey Schaufler
2017-05-25  6:53   ` David Howells [this message]
2017-05-25  6:53     ` David Howells
2017-05-25  6:53     ` David Howells
2017-05-25 18:18     ` Casey Schaufler
2017-05-25 18:18       ` Casey Schaufler
2017-05-25 18:18       ` Casey Schaufler
2017-05-26 12:43     ` David Howells
2017-05-26 12:43       ` David Howells
2017-05-26 12:43       ` David Howells
2017-05-26 17:08       ` joeyli
2017-05-26 17:08         ` joeyli
2017-05-26  8:16   ` joeyli
2017-05-26  8:16     ` joeyli
2017-05-26  8:16     ` joeyli
2017-05-24 14:45 ` [PATCH 4/5] efi: Lock down the kernel if booted in secure boot mode David Howells
2017-05-24 14:45   ` David Howells
2017-05-26  8:29   ` joeyli
2017-05-26  8:29     ` joeyli
2017-05-24 14:46 ` [PATCH 5/5] Add a sysrq option to exit " David Howells
2017-05-24 14:46   ` David Howells
2017-05-27  4:06   ` joeyli
2017-05-27  4:06     ` joeyli
2017-05-30 10:49   ` James Morris
2017-05-30 10:49     ` James Morris
2017-05-30 10:49     ` James Morris
2017-05-30 18:57 ` [PATCH 0/5] security, efi: Set lockdown if in " Ard Biesheuvel
2017-05-30 18:57   ` Ard Biesheuvel
2017-05-31  9:23 ` David Howells
2017-05-31  9:23   ` David Howells
2017-05-31  9:23   ` David Howells
2017-05-31 11:39   ` Ard Biesheuvel
2017-05-31 11:39     ` Ard Biesheuvel
2017-05-31 11:39     ` Ard Biesheuvel
2017-05-31 13:33   ` David Howells
2017-05-31 13:33     ` David Howells
2017-05-31 14:06     ` Ard Biesheuvel
2017-05-31 14:06       ` Ard Biesheuvel
2017-06-06  9:34   ` David Howells
2017-06-06  9:34     ` David Howells
2017-06-06  9:34     ` David Howells
2017-06-09 17:33     ` Ard Biesheuvel
2017-06-09 17:33       ` Ard Biesheuvel
2017-06-09 17:33       ` Ard Biesheuvel
2017-06-09 19:22       ` Kees Cook
2017-06-09 19:22         ` Kees Cook
  -- strict thread matches above, loose matches on Subject: below --
2017-04-06 12:49 [PATCH 1/5] efi: Move the x86 secure boot switch to generic code David Howells
2017-04-06 12:50 ` [PATCH 3/5] Add the ability to lock down access to the running kernel image David Howells
2017-04-06 12:50   ` David Howells
2017-04-06 22:45   ` James Morris
2017-04-06 22:45     ` James Morris
2017-04-06 22:45     ` James Morris

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