Re: [RFC Part2 PATCH v3 17/26] KVM: SVM: Add support for SEV LAUNCH_MEASURE command

[Borislav Petkov]

On Mon, Jul 24, 2017 at 03:02:54PM -0500, Brijesh Singh wrote:
> The command is used to retrieve the measurement of memory encrypted
> through the LAUNCH_UPDATE_DATA command. This measurement can be used
> for attestation purposes.
> 
> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
> ---
>  arch/x86/kvm/svm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 91b070f..9b672eb 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -5957,6 +5957,54 @@ static int sev_launch_update_data(struct kvm *kvm, 
> struct kvm_sev_cmd *argp)
>       return ret;
>  }
>  
> +static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
> +{
> +     struct sev_data_launch_measure *data = NULL;
> +     struct kvm_sev_launch_measure params;
> +     void *addr = NULL;
> +     int ret;
> +
> +     if (!sev_guest(kvm))
> +             return -ENOTTY;
> +
> +     if (copy_from_user(&params, (void *)argp->data,
> +                             sizeof(struct kvm_sev_launch_measure)))
> +             return -EFAULT;
> +
> +     data = kzalloc(sizeof(*data), GFP_KERNEL);
> +     if (!data)
> +             return -ENOMEM;
> +
> +     if (params.address && params.length) {


Same notes as before: check userspace data and make data a stack var.

Thx.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 
(AG Nürnberg)
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