Commit 27461d69 authored by Prasad J Pandit's avatar Prasad J Pandit Committed by David Gibson
Browse files

ppc: add host-serial and host-model machine attributes (CVE-2019-8934) 

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: default avatarDaniel P. Berrangé <berrange@redhat.com>
Fix-suggested-by: default avatarDaniel P. Berrangé <berrange@redhat.com>
Signed-off-by: default avatarPrasad J Pandit <pjp@fedoraproject.org>
Message-Id: <20190218181349.23885-1-ppandit@redhat.com>
Reviewed-by: default avatarDaniel P. Berrangé <berrange@redhat.com>
Reviewed-by: default avatarGreg Kurz <groug@kaod.org>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 6eebe6dc

hw/ppc/spapr.c

+70 −6
Original line number Diff line number Diff line
@@ -1247,14 +1247,31 @@ 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 (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 (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);
@@ -3144,6 +3161,36 @@ 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);
@@ -3189,6 +3236,17 @@ 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)
@@ -4086,9 +4144,15 @@ 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;

}

include/hw/ppc/spapr.h

+2 −0
Original line number Diff line number Diff line
@@ -177,6 +177,8 @@ struct sPAPRMachineState { 


    /*< public >*/

    char *kvm_type;

    char *host_model;

    char *host_serial;



    int32_t irq_map_nr;

    unsigned long *irq_map;