From: "H. Peter Anvin" <hpa@zytor.com>
To: Matthew Garrett <matthew.garrett@nebula.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"keescook@chromium.org" <keescook@chromium.org>
Subject: Re: [PATCH V3 03/11] x86: Lock down IO port access when module security is enabled
Date: Thu, 05 Sep 2013 08:36:51 -0700 [thread overview]
Message-ID: <69eec644-f26f-410c-bb76-0b7695dde65c@email.android.com> (raw)
In-Reply-To: <1378353524.13193.26.camel@x230>
Sigh. That capability really is fscked up.
Matthew Garrett <matthew.garrett@nebula.com> wrote:
>On Wed, 2013-09-04 at 20:52 -0700, H. Peter Anvin wrote:
>> On 09/03/2013 04:50 PM, Matthew Garrett wrote:
>> > IO port access would permit users to gain access to PCI
>configuration
>> > registers, which in turn (on a lot of hardware) give access to MMIO
>register
>> > space. This would potentially permit root to trigger arbitrary DMA,
>so lock
>> > it down by default.
>> >
>> > Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
>>
>> Seriously... just deny CAP_SYS_RAWIO to any system in secure mode.
>
>No. CAP_SYS_RAWIO blocks things that we don't want blocked (x86
>microcode updates, various disk ioctls, *device firmware uploads* and a
>few others) - the semantics just don't match. We could relax those
>permissions, but then we'd potentially break someone else's security
>considerations.
--
Sent from my mobile phone. Please pardon brevity and lack of formatting.
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
To: Matthew Garrett
<matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org>
Cc: "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org"
<keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH V3 03/11] x86: Lock down IO port access when module security is enabled
Date: Thu, 05 Sep 2013 08:36:51 -0700 [thread overview]
Message-ID: <69eec644-f26f-410c-bb76-0b7695dde65c@email.android.com> (raw)
In-Reply-To: <1378353524.13193.26.camel@x230>
Sigh. That capability really is fscked up.
Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> wrote:
>On Wed, 2013-09-04 at 20:52 -0700, H. Peter Anvin wrote:
>> On 09/03/2013 04:50 PM, Matthew Garrett wrote:
>> > IO port access would permit users to gain access to PCI
>configuration
>> > registers, which in turn (on a lot of hardware) give access to MMIO
>register
>> > space. This would potentially permit root to trigger arbitrary DMA,
>so lock
>> > it down by default.
>> >
>> > Signed-off-by: Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org>
>>
>> Seriously... just deny CAP_SYS_RAWIO to any system in secure mode.
>
>No. CAP_SYS_RAWIO blocks things that we don't want blocked (x86
>microcode updates, various disk ioctls, *device firmware uploads* and a
>few others) - the semantics just don't match. We could relax those
>permissions, but then we'd potentially break someone else's security
>considerations.
--
Sent from my mobile phone. Please pardon brevity and lack of formatting.
next prev parent reply other threads:[~2013-09-05 15:37 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 23:50 Matthew Garrett
2013-09-03 23:50 ` (unknown), Matthew Garrett
2013-09-03 23:50 ` [PATCH V3 01/11] Add secure_modules() call Matthew Garrett
2013-09-04 0:45 ` James Morris
2013-09-04 0:45 ` James Morris
2013-09-05 2:14 ` joeyli
2013-09-05 2:14 ` joeyli
2013-09-03 23:50 ` [PATCH V3 02/11] PCI: Lock down BAR access when module security is enabled Matthew Garrett
2013-09-04 0:45 ` James Morris
2013-09-04 0:45 ` James Morris
2013-09-04 16:57 ` David Woodhouse
2013-09-04 16:57 ` David Woodhouse
2013-09-04 17:04 ` Matthew Garrett
2013-09-04 17:04 ` Matthew Garrett
2013-09-04 18:58 ` David Woodhouse
2013-09-04 19:01 ` Matthew Garrett
2013-09-04 19:01 ` Matthew Garrett
2013-09-04 19:31 ` David Woodhouse
2013-09-04 19:31 ` David Woodhouse
2013-09-03 23:50 ` [PATCH V3 03/11] x86: Lock down IO port " Matthew Garrett
2013-09-04 0:45 ` James Morris
2013-09-05 3:52 ` H. Peter Anvin
2013-09-05 3:52 ` H. Peter Anvin
2013-09-05 3:58 ` Matthew Garrett
2013-09-05 3:58 ` Matthew Garrett
2013-09-05 15:36 ` H. Peter Anvin [this message]
2013-09-05 15:36 ` H. Peter Anvin
2013-09-03 23:50 ` [PATCH V3 04/11] ACPI: Limit access to custom_method Matthew Garrett
2013-09-04 0:46 ` James Morris
2013-09-04 0:46 ` James Morris
2013-09-03 23:50 ` [PATCH V3 05/11] asus-wmi: Restrict debugfs interface when module loading is restricted Matthew Garrett
2013-09-04 0:46 ` James Morris
2013-09-04 0:46 ` James Morris
2013-09-03 23:50 ` [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem " Matthew Garrett
2013-09-04 0:47 ` James Morris
2013-09-04 0:47 ` James Morris
2013-09-03 23:50 ` [PATCH V3 07/11] acpi: Ignore acpi_rsdp kernel parameter " Matthew Garrett
2013-09-03 23:50 ` Matthew Garrett
2013-09-03 23:50 ` [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Matthew Garrett
2013-09-04 0:48 ` James Morris
2013-09-04 0:48 ` James Morris
2013-09-04 20:09 ` jerry.hoemann
2013-09-04 20:09 ` jerry.hoemann-VXdhtT5mjnY
2013-09-04 20:12 ` Matthew Garrett
2013-09-04 20:12 ` Matthew Garrett
2013-09-04 20:12 ` Matthew Garrett
2013-09-04 20:14 ` Josh Boyer
2013-09-04 20:14 ` Josh Boyer
2013-09-04 20:14 ` Josh Boyer
2013-09-08 6:40 ` Greg KH
2013-09-08 6:40 ` Greg KH
2013-09-08 6:44 ` Matthew Garrett
2013-09-08 6:44 ` Matthew Garrett
2013-09-08 7:24 ` Greg KH
2013-09-08 7:24 ` Greg KH
2013-09-08 14:40 ` Matthew Garrett
2013-09-08 14:40 ` Matthew Garrett
2013-09-08 15:51 ` Kees Cook
2013-09-08 15:51 ` Kees Cook
2013-09-08 16:18 ` Greg KH
2013-09-08 16:18 ` Greg KH
2013-09-08 16:24 ` Matthew Garrett
2013-09-08 16:24 ` Matthew Garrett
2013-09-08 16:39 ` Greg KH
2013-09-08 16:39 ` Greg KH
2013-09-08 16:59 ` Matthew Garrett
2013-09-08 16:59 ` Matthew Garrett
2013-09-08 17:22 ` Greg KH
2013-09-08 17:22 ` Greg KH
2013-09-08 17:25 ` Matthew Garrett
2013-09-08 17:25 ` Matthew Garrett
2013-09-08 17:11 ` James Bottomley
2013-09-08 17:11 ` James Bottomley
2013-09-08 17:15 ` Matthew Garrett
2013-09-08 17:15 ` Matthew Garrett
2013-09-08 17:22 ` James Bottomley
2013-09-08 17:22 ` James Bottomley
2013-09-08 17:27 ` Matthew Garrett
2013-09-08 17:27 ` Matthew Garrett
2013-09-08 17:32 ` James Bottomley
2013-09-08 17:32 ` James Bottomley
2013-09-08 17:38 ` Matthew Garrett
2013-09-08 17:38 ` Matthew Garrett
2013-09-03 23:50 ` [PATCH V3 09/11] uswsusp: Disable when module loading is restricted Matthew Garrett
2013-09-04 0:48 ` James Morris
2013-09-04 0:48 ` James Morris
2013-09-05 3:20 ` joeyli
2013-09-05 3:20 ` joeyli
2013-09-03 23:50 ` [PATCH V3 10/11] x86: Restrict MSR access " Matthew Garrett
2013-09-04 0:49 ` James Morris
2013-09-04 0:49 ` James Morris
2013-09-03 23:50 ` [PATCH V3 11/11] Add option to automatically enforce module signatures when in Secure Boot mode Matthew Garrett
2013-09-03 23:50 ` Matthew Garrett
2013-09-04 1:42 ` James Morris
2013-09-04 1:42 ` James Morris
2013-09-04 1:42 ` Matthew Garrett
2013-09-04 1:42 ` Matthew Garrett
2013-09-05 3:13 ` joeyli
2013-09-05 8:24 ` joeyli
2013-09-05 8:24 ` joeyli
2013-09-05 10:16 ` Matt Fleming
2013-09-05 10:16 ` Matt Fleming
2013-09-05 12:54 ` Matthew Garrett
2013-09-05 12:54 ` Matthew Garrett
2013-09-04 15:53 ` Kees Cook
2013-09-04 15:53 ` Re: Kees Cook
2013-09-04 16:05 ` Re: Josh Boyer
2013-09-04 16:05 ` Re: Josh Boyer
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