From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Balbir Singh <bsingharora@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
Stewart Smith <stewart@linux.vnet.ibm.com>,
bhe@redhat.com, arnd@arndb.de, Petr Tesarik <ptesarik@suse.cz>,
linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
dyoung@redhat.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 0/3] extend kexec_file_load system call
Date: Wed, 20 Jul 2016 09:35:30 +0100 [thread overview]
Message-ID: <20160720083530.GK1041@n2100.armlinux.org.uk> (raw)
In-Reply-To: <8a8b2909-7f95-03e4-bf8e-dd29b5fc1fba@gmail.com>
On Wed, Jul 20, 2016 at 01:45:42PM +1000, Balbir Singh wrote:
> > IOW, if your kernel forced signature verification, you should not be
> > able to do sig_enforce=0. If you kernel did not have
> > CONFIG_MODULE_SIG_FORCE=y, then sig_enforce should be 0 by default anyway
> > and you are not making it worse using command line.
>
> OK.. I checked and you are right, but that is an example and there are
> other things like security=, thermal.*, nosmep, nosmap that need auditing
> for safety and might hurt the system security if used. I still think
> think that assuming you can pass any command line without breaking security
> is a broken argument.
Quite, and you don't need to run code in a privileged environment to do
any of that.
It's also not trivial to protect against: new kernels gain new arguments
which older kernels may not know about. No matter how much protection
is built into older kernels, newer kernels can become vulnerable through
the addition of further arguments.
Also, how sure are we that there are no stack overflow issues with kernel
command line parsing? Can we be sure that there's none? This is
something which happens early in the kernel boot, before the full memory
protections have been set up.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-07-20 8:36 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 1:41 [RFC 0/3] extend kexec_file_load system call AKASHI Takahiro
2016-07-12 1:41 ` [RFC 1/3] syscall: add kexec_file_load to generic unistd.h AKASHI Takahiro
2016-07-12 1:42 ` [RFC 2/3] kexec: add dtb info to struct kimage AKASHI Takahiro
2016-07-12 1:42 ` [RFC 3/3] kexec: extend kexec_file_load system call AKASHI Takahiro
2016-07-15 13:09 ` Vivek Goyal
2016-07-15 13:19 ` Mark Rutland
2016-07-18 2:30 ` Dave Young
2016-07-18 10:07 ` Mark Rutland
2016-07-19 0:55 ` Dave Young
2016-07-19 10:52 ` Mark Rutland
2016-07-19 12:24 ` Vivek Goyal
2016-07-19 12:47 ` Mark Rutland
2016-07-19 13:26 ` Vivek Goyal
2016-07-20 11:41 ` David Laight
2016-07-21 9:21 ` Russell King - ARM Linux
2016-07-18 2:33 ` Dave Young
2016-07-27 0:24 ` [PATCH v2 " Thiago Jung Bauermann
2016-08-05 20:46 ` Thiago Jung Bauermann
2016-07-12 13:25 ` [RFC 0/3] " Eric W. Biederman
2016-07-12 13:58 ` Thiago Jung Bauermann
2016-07-12 14:02 ` Vivek Goyal
2016-07-12 23:45 ` Stewart Smith
2016-07-13 13:27 ` Vivek Goyal
2016-07-12 14:02 ` Arnd Bergmann
2016-07-12 14:18 ` Vivek Goyal
2016-07-12 14:24 ` Arnd Bergmann
2016-07-12 14:50 ` Mark Rutland
2016-07-13 2:36 ` Dave Young
2016-07-13 8:01 ` Arnd Bergmann
2016-07-13 8:23 ` Stewart Smith
2016-07-13 9:41 ` Mark Rutland
2016-07-13 13:13 ` Arnd Bergmann
2016-07-13 18:45 ` Thiago Jung Bauermann
2016-07-13 19:59 ` Arnd Bergmann
2016-07-14 2:18 ` Thiago Jung Bauermann
2016-07-14 8:29 ` Arnd Bergmann
2016-07-15 1:44 ` Thiago Jung Bauermann
2016-07-15 7:31 ` Arnd Bergmann
2016-07-15 13:26 ` Vivek Goyal
2016-07-15 13:33 ` Mark Rutland
2016-07-15 15:29 ` Thiago Jung Bauermann
2016-07-15 15:47 ` Mark Rutland
2016-07-15 13:42 ` Russell King - ARM Linux
2016-07-15 20:26 ` Arnd Bergmann
2016-07-15 21:03 ` Thiago Jung Bauermann
2016-07-22 0:09 ` Thiago Jung Bauermann
2016-07-22 0:53 ` Jeremy Kerr
2016-07-22 2:54 ` Michael Ellerman
2016-07-22 20:41 ` Thiago Jung Bauermann
2016-07-15 8:49 ` Russell King - ARM Linux
2016-07-15 13:03 ` Vivek Goyal
2016-07-13 9:34 ` Mark Rutland
2016-07-13 17:38 ` AKASHI Takahiro
2016-07-13 17:58 ` Mark Rutland
2016-07-13 19:57 ` Arnd Bergmann
2016-07-14 12:42 ` Mark Rutland
2016-07-14 1:54 ` Dave Young
2016-07-14 1:50 ` Dave Young
2016-07-12 16:25 ` Thiago Jung Bauermann
2016-07-12 20:58 ` Petr Tesarik
2016-07-12 21:22 ` Eric W. Biederman
2016-07-12 21:36 ` Eric W. Biederman
2016-07-12 21:53 ` Petr Tesarik
2016-07-12 22:18 ` Russell King - ARM Linux
2016-07-13 4:59 ` Stewart Smith
2016-07-13 7:36 ` Russell King - ARM Linux
2016-07-13 7:47 ` Ard Biesheuvel
2016-07-13 8:09 ` Russell King - ARM Linux
2016-07-13 8:20 ` Stewart Smith
2016-07-13 7:55 ` Stewart Smith
2016-07-13 8:26 ` Russell King - ARM Linux
2016-07-13 8:36 ` Dave Young
2016-07-13 8:57 ` Petr Tesarik
2016-07-13 13:03 ` Vivek Goyal
2016-07-13 17:40 ` Russell King - ARM Linux
2016-07-13 18:22 ` Vivek Goyal
2016-07-18 12:46 ` Balbir Singh
2016-07-18 13:26 ` Vivek Goyal
2016-07-18 13:38 ` Vivek Goyal
2016-07-20 3:45 ` Balbir Singh
2016-07-20 8:35 ` Russell King - ARM Linux [this message]
2016-07-20 11:12 ` Arnd Bergmann
2016-07-20 15:50 ` Thiago Jung Bauermann
2016-07-20 12:46 ` Vivek Goyal
2016-07-20 12:27 ` Vivek Goyal
2016-07-12 23:41 ` Stewart Smith
2016-07-13 13:25 ` Vivek Goyal
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