On Wed, Jul 10, 2019 at 1:13 PM Singh, Brijesh <brijesh.singh@xxxxxxx> wrote:
>
> +static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
> +{
> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> + void *amd_cert = NULL, *session_data = NULL;
> + void *pdh_cert = NULL, *plat_cert = NULL;
> + struct sev_data_send_start *data = NULL;
> + struct kvm_sev_send_start params;
> + int ret;
> +
> + if (!sev_guest(kvm))
> + return -ENOTTY;
> +
> + if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data,
> + sizeof(struct kvm_sev_send_start)))
> + return -EFAULT;
> +
> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + /* userspace wants to query the session length */
> + if (!params.session_len)
> + goto cmd;
> +
> + if (!params.pdh_cert_uaddr || !params.pdh_cert_len ||
> + !params.session_uaddr)
> + return -EINVAL;
I think pdh_cert is only required if the guest policy SEV bit is set.
Can pdh_cert be optional?
> +
> + /* copy the certificate blobs from userspace */
> + pdh_cert = psp_copy_user_blob(params.pdh_cert_uaddr, params.pdh_cert_len);
> + if (IS_ERR(pdh_cert)) {
> + ret = PTR_ERR(pdh_cert);
> + goto e_free;
> + }
> +
> + data->pdh_cert_address = __psp_pa(pdh_cert);
> + data->pdh_cert_len = params.pdh_cert_len;
> +
> + plat_cert = psp_copy_user_blob(params.plat_cert_uaddr, params.plat_cert_len);
> + if (IS_ERR(plat_cert)) {
> + ret = PTR_ERR(plat_cert);
> + goto e_free_pdh;
> + }
I think plat_cert is also only required if the guest policy SEV bit is
set. Can plat_cert also be optional?
> +
> + data->plat_cert_address = __psp_pa(plat_cert);
> + data->plat_cert_len = params.plat_cert_len;
> +
> + amd_cert = psp_copy_user_blob(params.amd_cert_uaddr, params.amd_cert_len);
> + if (IS_ERR(amd_cert)) {
> + ret = PTR_ERR(amd_cert);
> + goto e_free_plat_cert;
> + }
I think amd_cert is also only required if the guest policy SEV bit is
set. Can amd_cert also be optional?
> +
> + data->amd_cert_address = __psp_pa(amd_cert);
> + data->amd_cert_len = params.amd_cert_len;
> +
> + ret = -EINVAL;
> + if (params.session_len > SEV_FW_BLOB_MAX_SIZE)
> + goto e_free_amd_cert;
> +
> + ret = -ENOMEM;
> + session_data = kmalloc(params.session_len, GFP_KERNEL);
> + if (!session_data)
> + goto e_free_amd_cert;
This pattern of returning -EINVAL if a length is greater than
SEV_FW_BLOB_MAX_SIZE and -ENOMEM if kmalloc fails is used at
sev_launch_measure. And I think in your later patches you do similar,
did you consider factoring this out into a helper function similar to
psp_copy_user_blob?
