| Message ID | ebd27b01905fd23bf9144800c1767e88@alterapraxis.com |
|---|---|
| State | Accepted |
| Headers | show |
On Tue, Jan 05, 2016 at 04:12:38AM +1100, eocallaghan@alterapraxis.com wrote: > If the 'image' pointer has been advanced more than 'size', > we've already iterated through memory outside the resource window. > > We have zero control over whatever we find in the option ROM, > if it's even an option ROM and not just an accident of random > data just happening to look like an option ROM. > > Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com> This patch was somehow malformed, but I applied it by hand to pci/resource for v4.5, thanks, Edward! > --- > drivers/pci/rom.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c > index eb0ad53..45987ad 100644 > --- a/drivers/pci/rom.c > +++ b/drivers/pci/rom.c > @@ -96,6 +96,9 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void > __iomem *rom, size_t size) > last_image = readb(pds + 21) & 0x80; > length = readw(pds + 16); > image += length * 512; > + /* Avoid iterating through memory outside the resource window */ > + if (image > rom + size) > + break; > } while (length && !last_image); > > /* never return a size larger than the PCI resource window */ > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c index eb0ad53..45987ad 100644 --- a/drivers/pci/rom.c +++ b/drivers/pci/rom.c @@ -96,6 +96,9 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size) last_image = readb(pds + 21) & 0x80; length = readw(pds + 16); image += length * 512; + /* Avoid iterating through memory outside the resource window */ + if (image > rom + size) + break; } while (length && !last_image);
If the 'image' pointer has been advanced more than 'size', we've already iterated through memory outside the resource window. We have zero control over whatever we find in the option ROM, if it's even an option ROM and not just an accident of random data just happening to look like an option ROM. Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com> --- drivers/pci/rom.c | 3 +++ 1 file changed, 3 insertions(+) /* never return a size larger than the PCI resource window */