Re: [Qemu-devel] [PATCH v4] ppc: add host-serial and host-model machine attributes

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Feb 18, 2019 at 11:43:49PM +0530, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> On ppc hosts, hypervisor shares following system attributes
> 
>   - /proc/device-tree/system-id
>   - /proc/device-tree/model
> 
> with a guest. This could lead to information leakage and misuse.[*]
> Add machine attributes to control such system information exposure
> to a guest.
> 
> [*] https://wiki.openstack.org/wiki/OSSN/OSSN-0028
> 
> Reported-by: Daniel P. Berrangé <berrange@redhat.com>
> Fix-suggested-by: Daniel P. Berrangé <berrange@redhat.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>

Applied to ppc-for-4.0, thanks.

> ---
>  hw/ppc/spapr.c         | 76 ++++++++++++++++++++++++++++++++++++++----
>  include/hw/ppc/spapr.h |  2 ++
>  2 files changed, 72 insertions(+), 6 deletions(-)
> 
> Update v4: remove NULL initializations in spapr_instance_init()
>   -> https://lists.gnu.org/archive/html/qemu-devel/2019-02/msg04554.html
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 0942f35bf8..8786c4c4ca 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1249,13 +1249,30 @@ static void *spapr_build_fdt(sPAPRMachineState *spapr,
>       * Add info to guest to indentify which host is it being run on
>       * and what is the uuid of the guest
>       */
> -    if (kvmppc_get_host_model(&buf)) {
> -        _FDT(fdt_setprop_string(fdt, 0, "host-model", buf));
> -        g_free(buf);
> +    if (spapr->host_model && !g_str_equal(spapr->host_model, "none")) {
> +        if (g_str_equal(spapr->host_model, "passthrough")) {
> +            /* -M host-model=passthrough */
> +            if (kvmppc_get_host_model(&buf)) {
> +                _FDT(fdt_setprop_string(fdt, 0, "host-model", buf));
> +                g_free(buf);
> +            }
> +        } else {
> +            /* -M host-model=<user-string> */
> +            _FDT(fdt_setprop_string(fdt, 0, "host-model", spapr->host_model));
> +        }
>      }
> -    if (kvmppc_get_host_serial(&buf)) {
> -        _FDT(fdt_setprop_string(fdt, 0, "host-serial", buf));
> -        g_free(buf);
> +
> +    if (spapr->host_serial && !g_str_equal(spapr->host_serial, "none")) {
> +        if (g_str_equal(spapr->host_serial, "passthrough")) {
> +            /* -M host-serial=passthrough */
> +            if (kvmppc_get_host_serial(&buf)) {
> +                _FDT(fdt_setprop_string(fdt, 0, "host-serial", buf));
> +                g_free(buf);
> +            }
> +        } else {
> +            /* -M host-serial=<user-string> */
> +            _FDT(fdt_setprop_string(fdt, 0, "host-serial", spapr->host_serial));
> +        }
>      }
>  
>      buf = qemu_uuid_unparse_strdup(&qemu_uuid);
> @@ -3138,6 +3155,36 @@ static void spapr_set_ic_mode(Object *obj, const char *value, Error **errp)
>      }
>  }
>  
> +static char *spapr_get_host_model(Object *obj, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    return g_strdup(spapr->host_model);
> +}
> +
> +static void spapr_set_host_model(Object *obj, const char *value, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    g_free(spapr->host_model);
> +    spapr->host_model = g_strdup(value);
> +}
> +
> +static char *spapr_get_host_serial(Object *obj, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    return g_strdup(spapr->host_serial);
> +}
> +
> +static void spapr_set_host_serial(Object *obj, const char *value, Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> +
> +    g_free(spapr->host_serial);
> +    spapr->host_serial = g_strdup(value);
> +}
> +
>  static void spapr_instance_init(Object *obj)
>  {
>      sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> @@ -3183,6 +3230,17 @@ static void spapr_instance_init(Object *obj)
>      object_property_set_description(obj, "ic-mode",
>                   "Specifies the interrupt controller mode (xics, xive, dual)",
>                   NULL);
> +
> +    object_property_add_str(obj, "host-model",
> +        spapr_get_host_model, spapr_set_host_model,
> +        &error_abort);
> +    object_property_set_description(obj, "host-model",
> +        "Set host's model-id to use - none|passthrough|string", &error_abort);
> +    object_property_add_str(obj, "host-serial",
> +        spapr_get_host_serial, spapr_set_host_serial,
> +        &error_abort);
> +    object_property_set_description(obj, "host-serial",
> +        "Set host's system-id to use - none|passthrough|string", &error_abort);
>  }
>  
>  static void spapr_machine_finalizefn(Object *obj)
> @@ -4080,9 +4138,15 @@ DEFINE_SPAPR_MACHINE(4_0, "4.0", true);
>  static void spapr_machine_3_1_class_options(MachineClass *mc)
>  {
>      sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
> +    static GlobalProperty compat[] = {
> +        { TYPE_SPAPR_MACHINE, "host-model", "passthrough" },
> +        { TYPE_SPAPR_MACHINE, "host-serial", "passthrough" },
> +    };
>  
>      spapr_machine_4_0_class_options(mc);
>      compat_props_add(mc->compat_props, hw_compat_3_1, hw_compat_3_1_len);
> +    compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
> +
>      mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");
>      smc->update_dt_enabled = false;
>  }
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index a947a0a0dc..e004a570d8 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -177,6 +177,8 @@ struct sPAPRMachineState {
>  
>      /*< public >*/
>      char *kvm_type;
> +    char *host_model;
> +    char *host_serial;
>  
>      const char *icp_type;
>      int32_t irq_map_nr;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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