From: Matthew Garrett <matthew.garrett@nebula.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Kees Cook <keescook@chromium.org>,
Greg KH <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>
Subject: Re: [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions
Date: Sun, 8 Sep 2013 17:15:42 +0000 [thread overview]
Message-ID: <1378660541.2300.19.camel@x230> (raw)
In-Reply-To: <1378660284.2429.11.camel@dabdike.int.hansenpartnership.com>
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1128 bytes --]
On Sun, 2013-09-08 at 10:11 -0700, James Bottomley wrote:
> That's not true if you look at the use cases. Distros use signed
> modules to taint the kernel: insert an unsigned one and the kernel
> taints; insert a properly signed one and it doesn't. They use it for
> support to tell if you've been adhering to your contract. That use case
> has nothing to do with security.
That use case has nothing to do with this patch, either. It's completely
unaffected. This only triggers if the kernel is configured to refuse the
loading of unsigned modules.
> The analogy is rubbish. I can give away CAP_SYS_MODULE and enforce what
> modules those I've given the permission to can insert by signing them.
> I keep CAP_SYS_BOOT, so they can't use kexec to subvert this.
Yeah, that's a good argument for why capabilities are mostly pointless.
If I have CAP_SYS_BOOT I can give myself any other capabilities. Why
bother?
--
Matthew Garrett <matthew.garrett@nebula.com>
ÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥
next prev parent reply other threads:[~2013-09-08 17:15 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 23:50 Matthew Garrett
2013-09-03 23:50 ` [PATCH V3 01/11] Add secure_modules() call Matthew Garrett
2013-09-04 0:45 ` James Morris
2013-09-05 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 16:57 ` David Woodhouse
2013-09-04 17:04 ` Matthew Garrett
2013-09-04 18:58 ` David Woodhouse
2013-09-04 19:01 ` Matthew Garrett
2013-09-04 19:31 ` 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 3:58 ` Matthew Garrett
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
2013-09-03 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
2013-09-03 23:50 ` [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem " Matthew Garrett
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 ` [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 20:09 ` jerry.hoemann
2013-09-04 20:12 ` Matthew Garrett
2013-09-04 20:14 ` Josh Boyer
2013-09-08 6:40 ` Greg KH
2013-09-08 6:44 ` Matthew Garrett
2013-09-08 7:24 ` Greg KH
2013-09-08 14:40 ` Matthew Garrett
2013-09-08 15:51 ` Kees Cook
2013-09-08 16:18 ` Greg KH
2013-09-08 16:24 ` Matthew Garrett
2013-09-08 16:39 ` Greg KH
2013-09-08 16:59 ` Matthew Garrett
2013-09-08 17:22 ` Greg KH
2013-09-08 17:25 ` Matthew Garrett
2013-09-08 17:11 ` James Bottomley
2013-09-08 17:15 ` Matthew Garrett [this message]
2013-09-08 17:22 ` James Bottomley
2013-09-08 17:27 ` Matthew Garrett
2013-09-08 17:32 ` James Bottomley
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
2013-09-05 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
2013-09-03 23:50 ` [PATCH V3 11/11] Add option to automatically enforce module signatures when in Secure Boot mode Matthew Garrett
2013-09-04 1:42 ` James Morris
2013-09-04 1:42 ` Matthew Garrett
2013-09-05 3:13 ` joeyli
2013-09-05 8:24 ` joeyli
2013-09-05 10:16 ` Matt Fleming
2013-09-05 12:54 ` Matthew Garrett
2013-09-04 15:53 ` Kees Cook
2013-09-04 16:05 ` Re: Josh Boyer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1378660541.2300.19.camel@x230 \
--to=matthew.garrett@nebula.com \
--cc=James.Bottomley@HansenPartnership.com \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=keescook@chromium.org \
--cc=linux-efi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox