Re: [PATCH v3] hw/pvrdma: Protect against buggy or malicious guest driver

[Marcel Apfelbaum]

Hi Yuval,
Thank you for the changes.

On Sun, Apr 3, 2022 at 11:54 AM Yuval Shaia <yuval.shaia.ml@gmail.com> wrote:
>
> Guest driver might execute HW commands when shared buffers are not yet
> allocated.
> This could happen on purpose (malicious guest) or because of some other
> guest/host address mapping error.
> We need to protect againts such case.
>
> Fixes: CVE-2022-1050
>
> Reported-by: Raven <wxhusst@gmail.com>
> Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
> ---
> v1 -> v2:
>         * Commit message changes
> v2 -> v3:
>         * Exclude cosmetic changes
> ---
>  hw/rdma/vmw/pvrdma_cmd.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
> index da7ddfa548..89db963c46 100644
> --- a/hw/rdma/vmw/pvrdma_cmd.c
> +++ b/hw/rdma/vmw/pvrdma_cmd.c
> @@ -796,6 +796,12 @@ int pvrdma_exec_cmd(PVRDMADev *dev)
>
>      dsr_info = &dev->dsr_info;
>
> +    if (!dsr_info->dsr) {
> +            /* Buggy or malicious guest driver */
> +            rdma_error_report("Exec command without dsr, req or rsp 
> buffers");
> +            goto out;
> +    }
> +
>      if (dsr_info->req->hdr.cmd >= sizeof(cmd_handlers) /
>                        sizeof(struct cmd_handler)) {
>          rdma_error_report("Unsupported command");
> --
> 2.20.1
>

cc-ing Peter and Philippe for a question:
Do we have a "Security Fixes" or a "Misc" subtree? Otherwise it will
have to wait a week or so.

Reviewed by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Thanks,
Marcel