"hw/net/can: sja1000 fix buff2frame* when dlc is out of std CAN 8 bytes"
On 7/29/21 2:33 PM, Pavel Pisa wrote:
> Problem reported by openEuler fuzz-sig group.
>
> The buff2frame_bas function (hw\net\can\can_sja1000.c)
> infoleak(qemu5.x~qemu6.x) or stack-overflow(qemu 4.x).
Cc: qemu-sta...@nongnu.org
> Reported-by: Qiang Ning <ningqia...@huawei.com>
> Signed-off-by: Pavel Pisa <p...@cmp.felk.cvut.cz>
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
> ---
> hw/net/can/can_sja1000.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/hw/net/can/can_sja1000.c b/hw/net/can/can_sja1000.c
> index 42d2f99dfb..34eea684ce 100644
> --- a/hw/net/can/can_sja1000.c
> +++ b/hw/net/can/can_sja1000.c
> @@ -275,6 +275,10 @@ static void buff2frame_pel(const uint8_t *buff,
> qemu_can_frame *frame)
> }
> frame->can_dlc = buff[0] & 0x0f;
>
> + if (frame->can_dlc > 8) {
> + frame->can_dlc = 8;
> + }
> +
> if (buff[0] & 0x80) { /* Extended */
> frame->can_id |= QEMU_CAN_EFF_FLAG;
> frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
> @@ -311,6 +315,10 @@ static void buff2frame_bas(const uint8_t *buff,
> qemu_can_frame *frame)
> }
> frame->can_dlc = buff[1] & 0x0f;
>
> + if (frame->can_dlc > 8) {
> + frame->can_dlc = 8;
> + }
> +
> for (i = 0; i < frame->can_dlc; i++) {
> frame->data[i] = buff[2 + i];
> }
>
