[PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses
Ingo Molnar
mingo at elte.hu
Fri Jul 1 10:46:41 EDT 2011
* Christoph Hellwig <hch at infradead.org> wrote:
> On Fri, Jul 01, 2011 at 04:37:35PM +0200, Ingo Molnar wrote:
>
> > After initial modules have loaded i essentially disable crash.ko
> > via /proc/sys/kernel/modules_disabled so rootkits have to work a
> > bit harder than that.
>
> Not sure for fedora as I don'[t have a kernel tree at hand right
> now, but for x86 systems at least RHEL6 has the module built in.
> [...]
Fedora Rawhide has it modular:
# grep CRASH /boot/config-2.6.38-0.rc7.git2.3.fc16.x86_64
CONFIG_CRASH=m
# rpm -ql kernel-2.6.38-0.rc7.git2.3.fc16.x86_64 | grep crash
/lib/modules/2.6.38-0.rc7.git2.3.fc16.x86_64/kernel/drivers/char/crash.ko
> [...] Either way we'll need some way to support crash properly in
> mainline, preferably in a boot-time opt-in way. [...]
Yes, boot-time opt-in was what i suggested.
> [...] I'd tend slightly toward optionally enabling /dev/mem for it
> instead of a separate driver, but if people prefer a different
> route I'm fine, too.
No, sharing the driver is perfectly fine and sane as long as this
weird usage is not enabled widely.
> Note that for normal crash usage read only access is just fine.
That's true as well. Petr?
Thanks,
Ingo
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