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SubjectRe: [Bug #11382] e1000e: 2.6.27-rc1 corrupts EEPROM/NVM
On Tue, 23 Sep 2008, David Miller wrote:

> I did some snooping around, and while doing so I noticed that the PCI
> mmap code for x86 doesn't do one bit of range checking on the size, or
> any other aspect of the request, wrt. the MMIO regions actually mapped
> in the BARs of the PCI device.

Ugh, indeed. Added Ingo and Jesse to CC.

> Yikes!
>
> It just does a reserve_memtype() on the address range, and says "ok".
>
> So if, for example, the X server tries to mmap() more than an MMIO bar
> actually maps, the kernel lets the user do this.
>
> It would be very interesting to add the appropriate checks to
> pci_mmap_page_range() in arch/x86/pci/i386.c, anyone who wants to do
> this can use the code in arch/sparc64/kernel/pci.c:
> __pci_mmap_make_offset() as a guide, and see what happens.

Absolutely. Or we can even do some dirty hackery in userspace, like
LD_PRELOADing X server and checking mmaps() that are close to MMIO regions
of affected devices.

> If the MMIO space regions of the video cards sit right before the
> E1000E ones on the effected systems, that would pretty much
> convince me that this is the kind of problem we are having here.

Unfortunately, looking at the lspci outputs that are in
https://bugzilla.novell.com/show_bug.cgi?id=425480 it seems to me that the
MMIO regions are quite far away from each other.

--
Jiri Kosina
SUSE Labs


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