On 17/06/2015 12:46, Petr Matousek wrote:
> Due converting PIO to the new memory read/write api we no longer provide
> separate I/O region lenghts for read and write operations. As a result,
> reading from PIT Mode/Command register will end with accessing
> pit->channels with invalid index.
>
> Fix this by ignoring read from the Mode/Command register.
>
> This is CVE-2015-3214.
>
> Signed-off-by: Petr Matousek <pmato...@redhat.com>
> Reported-by: Matt Tait <mattt...@google.com>
Fixes: 0505bcdec8228d8de39ab1a02644e71999e7c052
Applied, thanks.
Paolo
> ---
> hw/timer/i8254.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/hw/timer/i8254.c b/hw/timer/i8254.c
> index 3450c98..9b65a33 100644
> --- a/hw/timer/i8254.c
> +++ b/hw/timer/i8254.c
> @@ -196,6 +196,12 @@ static uint64_t pit_ioport_read(void *opaque, hwaddr
> addr,
> PITChannelState *s;
>
> addr &= 3;
> +
> + if (addr == 3) {
> + /* Mode/Command register is write only, read is ignored */
> + return 0;
> + }
> +
> s = &pit->channels[addr];
> if (s->status_latched) {
> s->status_latched = 0;
>
