On Thu, May 27, 2010 at 02:44:42PM +0900, Isaku Yamahata wrote:
> address and config_size are both unsigned.
> So check which is bigger before minus operation.
> Otherwise the result of minus can be unexpected
> big value.
>
> Signed-off-by: Isaku Yamahata <yamah...@valinux.co.jp>
An this happen in practice? If yes, how?
> ---
> hw/pci.c | 9 +++++++--
> 1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 3362842..39a6206 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -988,9 +988,14 @@ uint32_t pci_default_read_config(PCIDevice *d,
> uint32_t address, int len)
> {
> uint32_t val = 0;
> + uint32_t config_size = pci_config_size(d);
> assert(len == 1 || len == 2 || len == 4);
> - len = MIN(len, pci_config_size(d) - address);
> - memcpy(&val, d->config + address, len);
> + if (address < config_size) {
> + len = MIN(len, config_size - address);
> + memcpy(&val, d->config + address, len);
> + } else {
> + val = ~0;
> + }
> return le32_to_cpu(val);
> }
>
> --
> 1.6.6.1
>
