Xorg 6.8.99.5 + i915 drivers + kmem

Discuss usability issues, general maintenance, and general support issues for a grsecurity-enabled system.

Xorg 6.8.99.5 + i915 drivers + kmem

Postby mirrorsh » Tue May 10, 2005 9:44 pm

I turned off /dev/kmem access and X would no longer work on my centrino-based laptop. Actually what I should say is I turned off /dev/kmem access and then installed X and was surprised to see it not working, until I got around to checking dmesg. Anyway on my system the following:

!(offset == 0xc0000 && ((vma->vm_end - vma->vm_start) <= 0xf0000) in grsec_mem.c fixed the first /dev/[k]mem access...

but then it bombed trying to map 0xb7f4b000...0xb7f4c000

at this point I gave up adding more offsets, I'm out of my element here already. Disable privileged I/O is *NOT* enabled, btw. This is 2.6.11 gentoo hardened.

Anyway I'll just turn that feature off but I thought I'd pass the word on to more knowledgable people, in the event that there is a fix or whatever.

--
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Postby spender » Sat May 14, 2005 4:27 pm

I just added ATI radeon support to the /dev/(k)mem feature, and it may fix your problems as well. Apply this diff to your grsecurity/grsec_mem.c file:

http://cvsweb.grsecurity.net/index.cgi/ ... r1=1.1&f=u

Also, for debugging purposes (in case this doesn't fix your problem), can you also add the following, just below the "end = start + vma->vm_end - vma->vm_start" line:

if (start < __pa(high_memory)) printk(KERN_ALERT "start=%08lx end=%08lx\n", start, end);

Thanks

-Brad
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Postby std0ut » Wed May 18, 2005 8:35 am

@spender..

What about other graphic cards ?

And also, what's the catch of those patches (maybe i'm able to make myself the proper patch :)
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Postby spender » Wed May 18, 2005 9:52 am

Other cards work fine. The purpose of the patch is to only keep kernel memory from being written to. Previously, we were a little more restrictive than necessary.

-Brad
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it worked thanks (nt)

Postby mirrorsh » Sat May 21, 2005 10:36 am

nt
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