[Qemu-devel] Re: [PATCH] scsi-disk: add data direction checking

[Stefan Hajnoczi <stefanha@gmail.com>]

On Mon, Nov 22, 2010 at 10:15 AM, Hannes Reinecke <hare@suse.de> wrote:
> @@ -172,6 +170,9 @@ static void scsi_read_data(SCSIRequest *req)
>     /* No data transfer may already be in progress */
>     assert(r->req.aiocb == NULL);
>
> +    if (r->req.cmd.mode == SCSI_XFER_TO_DEV)
> +        BADF("Data transfer direction invalid\n");
> +
>     if (r->sector_count == (uint32_t)-1) {
>         DPRINTF("Read buf_len=%zd\n", r->iov[0].iov_len);
>         r->sector_count = 0;
> @@ -284,6 +285,9 @@ static int scsi_write_data(SCSIRequest *req)
>     /* No data transfer may already be in progress */
>     assert(r->req.aiocb == NULL);
>
> +    if (r->req.cmd.mode != SCSI_XFER_TO_DEV)
> +        BADF("Data transfer direction invalid\n");
> +
>     n = iov_size(r->iov, r->iov_num) / 512;
>     if (n) {
>         qemu_iovec_init_external(&r->qiov, r->iov, r->iov_num);

If the guest can trigger this then there must be a SCSI response (an
error?).  Right now BADF() will do fprintf(stderr) and then continue
executing.

Can we abort the operation?

Stefan