On Wed, Jul 20, 2011 at 07:49:34PM -0400, Donald Dutile wrote:
> Bounds check to avoid walking off config_map[]
> and corrupting what is after it.
>
> Signed-off-by: Donald Dutile <[email protected]>
> cc: Alex Williamson <[email protected]>
> cc: Michael S. Tsirkin <[email protected]>
> ---
>
> hw/pci.c | 16 ++++++++++++++--
> 1 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 5deaa04..9a7ff2d 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -2078,12 +2078,24 @@ int pci_add_capability(PCIDevice *pdev, uint8_t
> cap_id,
> }
> } else {
> int i;
> + uint32_t config_size = pci_config_size(pdev);
This is actually slightly wrong: even for express
devices, legacy capabilities can not spill out from
the low 256 bytes: the extended config space has its
own capability list always starting with the express
capability at offset 256.
> +
> + /* ensure don't walk off end of config_map[] */
> + if (offset > (config_size - size)) {
I prefer not to have () around math here.
> + fprintf(stderr, "ERROR: %04x:%02x:%02x.%x "
> + "Attempt to add PCI capability 0x%x at offset 0x%x,"
> + "size 0x%x, which exceeds emulated PCI config space
> 0x%x\n",
> + pci_find_domain(pdev->bus), pci_bus_num(pdev->bus),
> + PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
> + cap_id, offset, size, config_size);
> + return -EINVAL;
> + }
>
> for (i = offset; i < offset + size; i++) {
> if (pdev->config_map[i]) {
> fprintf(stderr, "ERROR: %04x:%02x:%02x.%x "
> - "Attempt to add PCI capability %x at offset "
> - "%x overlaps existing capability %x at offset %x\n",
> + "Attempt to add PCI capability 0x%x at offset "
> + "0x%x overlaps existing capability 0x%x at offset
> 0x%x\n",
> pci_find_domain(pdev->bus), pci_bus_num(pdev->bus),
> PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
> cap_id, offset, pdev->config_map[i], i);
--
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