On Thu, Sep 25, 2008 at 9:15 AM, Jiri Kosina <jkosina@xxxxxxx> wrote: > 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. > Yup on my laptop these were far away and I wondered what could mangle things that badly. Well I'm out of the race, my attempts to re-write my eeprom using an eeprom from an equivalent laptop have totally failed and my BIOS won't boot anymore - so my laptop is == a brick. Dave. -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
