From: devzero@web.de
To: arjan@infradead.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: introduce /dev/mem restrictions with a config option
Date: Thu, 31 Jan 2008 15:04:28 +0100 [thread overview]
Message-ID: <137932353@web.de> (raw)
nice !
did you think about some boot-time param , e.g. "insecure-devmem" or something like that?
recompiling kernel is time consuming.....
From: Arjan van de Ven <arjan@linux.intel.com>
Subject: [PATCH] x86: introduce /dev/mem restrictions with a config option
This patch introduces a restriction on /dev/mem: Only non-memory can be
read or written unless the newly introduced config option is set.
The X server needs access to /dev/mem for the PCI space, but it doesn't need
access to memory; both the file permissions and SELinux permissions of /dev/mem
just make X effectively super-super powerful. With the exception of the
BIOS area, there's just no valid app that uses /dev/mem on actual memory.
Other popular users of /dev/mem are rootkits and the like.
(note: mmap access of memory via /dev/mem was already not allowed since
a really long time)
People who want to use /dev/mem for kernel debugging can enable the config
option.
The restrictions of this patch have been in the Fedora and RHEL kernels for
at least 4 years without any problems.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
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next reply other threads:[~2008-01-31 14:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-31 14:04 devzero [this message]
2008-01-31 14:41 ` [PATCH] x86: introduce /dev/mem restrictions with a config option Arjan van de Ven
-- strict thread matches above, loose matches on Subject: below --
2008-01-30 20:48 Arjan van de Ven
2008-01-31 16:53 ` Jan Engelhardt
2008-01-31 17:08 ` Arjan van de Ven
2008-01-31 17:42 ` H. Peter Anvin
2008-01-31 22:02 ` Jesse Barnes
2008-01-31 22:05 ` H. Peter Anvin
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