From nobody Fri May 3 02:21:45 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1498169420234174.5397234140346; Thu, 22 Jun 2017 15:10:20 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0A2117D0C6; Thu, 22 Jun 2017 22:10:16 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 18A3968D36; Thu, 22 Jun 2017 22:10:15 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id ED7124E985; Thu, 22 Jun 2017 22:10:13 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v5MMADoK004365 for ; Thu, 22 Jun 2017 18:10:13 -0400 Received: by smtp.corp.redhat.com (Postfix) id 118146FE47; Thu, 22 Jun 2017 22:10:13 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-116-36.phx2.redhat.com [10.3.116.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9B47F62923 for ; Thu, 22 Jun 2017 22:10:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 0A2117D0C6 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=libvir-list-bounces@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 0A2117D0C6 From: John Ferlan To: libvir-list@redhat.com Date: Thu, 22 Jun 2017 18:10:08 -0400 Message-Id: <20170622221008.11004-1-jferlan@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-loop: libvir-list@redhat.com Subject: [libvirt] [PATCH] events: Avoid double free possibility on remote call failure X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 22 Jun 2017 22:10:16 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" If a remote call fails during event registration (more than likely from a network failure or remote libvirtd restart timed just right), then when calling the virObjectEventStateDeregisterID we don't want to call the registered @freecb function because that breaks our contract that we would only call it after succesfully returning. If the @freecb routine were called, it could result in a double free from properly coded applications that free their opaque data on failure to register, as seen in the following details: Program terminated with signal 6, Aborted. #0 0x00007fc45cba15d7 in raise #1 0x00007fc45cba2cc8 in abort #2 0x00007fc45cbe12f7 in __libc_message #3 0x00007fc45cbe86d3 in _int_free #4 0x00007fc45d8d292c in PyDict_Fini #5 0x00007fc45d94f46a in Py_Finalize #6 0x00007fc45d960735 in Py_Main #7 0x00007fc45cb8daf5 in __libc_start_main #8 0x0000000000400721 in _start The double dereference of 'pyobj_cbData' is triggered in the following way: (1) libvirt_virConnectDomainEventRegisterAny is invoked. (2) the event is successfully added to the event callback list (virDomainEventStateRegisterClient in remoteConnectDomainEventRegisterAny returns 1 which means ok). (3) when function remoteConnectDomainEventRegisterAny is hit, network connection disconnected coincidently (or libvirtd is restarted) in the context of function 'call' then the connection is lost and the function 'call' failed, the branch virObjectEventStateDeregisterID is therefore taken. (4) 'pyobj_conn' is dereferenced the 1st time in libvirt_virConnectDomainEventFreeFunc. (5) 'pyobj_cbData' (refered to pyobj_conn) is dereferenced the 2nd time in libvirt_virConnectDomainEventRegisterAny. (6) the double free error is triggered. Resolve this by adding an @inhibitFreeCb boolean in order to avoid calling freecb in virObjectEventStateDeregisterID for any remote call failure in a remoteConnect*EventRegister* API. For remoteConnect*EventDeregister* call= s, the passed value would be false indicating they should run the freecb if it exists. Patch based on the investigation and initial patch posted by: fangying . Signed-off-by: John Ferlan --- Initial patch found at: https://www.redhat.com/archives/libvir-list/2017-June/msg00039.html based on feedback from Daniel Berrange to a previous posting: https://www.redhat.com/archives/libvir-list/2017-May/msg01089.html Since no new patch was posted, I posted my idea from review for consideration. src/bhyve/bhyve_driver.c | 2 +- src/conf/domain_event.c | 2 +- src/conf/object_event.c | 23 +++++++++++++++++------ src/conf/object_event.h | 3 ++- src/libxl/libxl_driver.c | 2 +- src/lxc/lxc_driver.c | 2 +- src/network/bridge_driver.c | 2 +- src/node_device/node_device_driver.c | 2 +- src/qemu/qemu_driver.c | 4 ++-- src/remote/remote_driver.c | 32 ++++++++++++++++---------------- src/secret/secret_driver.c | 2 +- src/storage/storage_driver.c | 2 +- src/test/test_driver.c | 8 ++++---- src/uml/uml_driver.c | 2 +- src/vz/vz_driver.c | 2 +- src/xen/xen_driver.c | 2 +- 16 files changed, 52 insertions(+), 40 deletions(-) diff --git a/src/bhyve/bhyve_driver.c b/src/bhyve/bhyve_driver.c index ed2221a..6722dc4 100644 --- a/src/bhyve/bhyve_driver.c +++ b/src/bhyve/bhyve_driver.c @@ -1503,7 +1503,7 @@ bhyveConnectDomainEventDeregisterAny(virConnectPtr co= nn, =20 if (virObjectEventStateDeregisterID(conn, privconn->domainEventState, - callbackID) < 0) + callbackID, false) < 0) return -1; =20 return 0; diff --git a/src/conf/domain_event.c b/src/conf/domain_event.c index 6e471d7..ff4c602 100644 --- a/src/conf/domain_event.c +++ b/src/conf/domain_event.c @@ -2301,7 +2301,7 @@ virDomainEventStateDeregister(virConnectPtr conn, NULL); if (callbackID < 0) return -1; - return virObjectEventStateDeregisterID(conn, state, callbackID); + return virObjectEventStateDeregisterID(conn, state, callbackID, false); } =20 =20 diff --git a/src/conf/object_event.c b/src/conf/object_event.c index e5f942f..5e944af 100644 --- a/src/conf/object_event.c +++ b/src/conf/object_event.c @@ -234,13 +234,15 @@ virObjectEventCallbackListCount(virConnectPtr conn, * @conn: pointer to the connection * @cbList: the list * @callback: the callback to remove + * @inhibitFreeCb: Inhibit calling the freecb * * Internal function to remove a callback from a virObjectEventCallbackLis= tPtr */ static int virObjectEventCallbackListRemoveID(virConnectPtr conn, virObjectEventCallbackListPtr cbList, - int callbackID) + int callbackID, + bool inhibitFreeCb) { size_t i; =20 @@ -256,7 +258,10 @@ virObjectEventCallbackListRemoveID(virConnectPtr conn, cb->key_filter ? cb->key = : NULL, cb->remoteID >=3D 0) - 1); =20 - if (cb->freecb) + /* inhibiting calling @freecb from error paths in register + * functions ensures the caller of the register function won't + * end up with a double free error */ + if (!inhibitFreeCb && cb->freecb) (*cb->freecb)(cb->opaque); virObjectEventCallbackFree(cb); VIR_DELETE_ELEMENT(cbList->callbacks, i, cbList->count); @@ -927,16 +932,22 @@ virObjectEventStateRegisterID(virConnectPtr conn, * @conn: connection to associate with callback * @state: object event state * @callbackID: ID of the function to remove from event + * @inhibitFreeCb: Inhibit the calling of a freecb * * Unregister the function @callbackID with connection @conn, - * from @state, for events. + * from @state, for events. If @inhibitFreeCb is true, then we + * are being called from a remote call failure path for the + * Event registration indicating a -1 return to the caller. The + * caller wouldn't expect us to run their freecb function if it + * exists, so we cannot do so. * * Returns: the number of callbacks still registered, or -1 on error */ int virObjectEventStateDeregisterID(virConnectPtr conn, virObjectEventStatePtr state, - int callbackID) + int callbackID, + bool inhibitFreeCb) { int ret; =20 @@ -946,8 +957,8 @@ virObjectEventStateDeregisterID(virConnectPtr conn, state->callbacks, callbackID); else - ret =3D virObjectEventCallbackListRemoveID(conn, - state->callbacks, callbac= kID); + ret =3D virObjectEventCallbackListRemoveID(conn, state->callbacks, + callbackID, inhibitFreeCb= ); =20 virObjectEventStateCleanupTimer(state, true); =20 diff --git a/src/conf/object_event.h b/src/conf/object_event.h index 7a9995e..b36fcc9 100644 --- a/src/conf/object_event.h +++ b/src/conf/object_event.h @@ -73,7 +73,8 @@ virObjectEventStateQueueRemote(virObjectEventStatePtr sta= te, int virObjectEventStateDeregisterID(virConnectPtr conn, virObjectEventStatePtr state, - int callbackID) + int callbackID, + bool inhibitFreeCb) ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2); =20 int diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 0d65342..2995324 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -5652,7 +5652,7 @@ libxlConnectDomainEventDeregisterAny(virConnectPtr co= nn, int callbackID) =20 if (virObjectEventStateDeregisterID(conn, driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) return -1; =20 return 0; diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c index 22c8b58..ec357c6 100644 --- a/src/lxc/lxc_driver.c +++ b/src/lxc/lxc_driver.c @@ -1479,7 +1479,7 @@ lxcConnectDomainEventDeregisterAny(virConnectPtr conn, =20 if (virObjectEventStateDeregisterID(conn, driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) return -1; =20 return 0; diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 3ba7018..e9ad77e 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -3001,7 +3001,7 @@ networkConnectNetworkEventDeregisterAny(virConnectPtr= conn, =20 if (virObjectEventStateDeregisterID(conn, driver->networkEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_de= vice_driver.c index 760d73a..37e4e19 100644 --- a/src/node_device/node_device_driver.c +++ b/src/node_device/node_device_driver.c @@ -690,7 +690,7 @@ nodeConnectNodeDeviceEventDeregisterAny(virConnectPtr c= onn, =20 if (virObjectEventStateDeregisterID(conn, driver->nodeDeviceEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index e91663c..8c10599 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -11826,7 +11826,7 @@ qemuConnectDomainEventDeregisterAny(virConnectPtr c= onn, =20 if (virObjectEventStateDeregisterID(conn, driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; @@ -18472,7 +18472,7 @@ qemuConnectDomainQemuMonitorEventDeregister(virConn= ectPtr conn, goto cleanup; =20 if (virObjectEventStateDeregisterID(conn, driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c index b452e8b..6ebf910 100644 --- a/src/remote/remote_driver.c +++ b/src/remote/remote_driver.c @@ -3066,7 +3066,7 @@ remoteConnectNetworkEventRegisterAny(virConnectPtr co= nn, (xdrproc_t) xdr_remote_connect_network_event_register_any= _args, (char *) &args, (xdrproc_t) xdr_remote_connect_network_event_register_any= _ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } virObjectEventStateSetRemote(conn, priv->eventState, callbackID, @@ -3099,7 +3099,7 @@ remoteConnectNetworkEventDeregisterAny(virConnectPtr = conn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this eventID, we need to disable @@ -3160,7 +3160,7 @@ remoteConnectStoragePoolEventRegisterAny(virConnectPt= r conn, (xdrproc_t) xdr_remote_connect_storage_pool_event_registe= r_any_args, (char *) &args, (xdrproc_t) xdr_remote_connect_storage_pool_event_registe= r_any_ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } =20 @@ -3193,7 +3193,7 @@ remoteConnectStoragePoolEventDeregisterAny(virConnect= Ptr conn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this eventID, we need to disable @@ -3256,7 +3256,7 @@ remoteConnectNodeDeviceEventRegisterAny(virConnectPtr= conn, (xdrproc_t) xdr_remote_connect_node_device_event_register= _any_args, (char *) &args, (xdrproc_t) xdr_remote_connect_node_device_event_register= _any_ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } =20 @@ -3290,7 +3290,7 @@ remoteConnectNodeDeviceEventDeregisterAny(virConnectP= tr conn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this eventID, we need to disable @@ -3353,7 +3353,7 @@ remoteConnectSecretEventRegisterAny(virConnectPtr con= n, (xdrproc_t) xdr_remote_connect_secret_event_register_any_= args, (char *) &args, (xdrproc_t) xdr_remote_connect_secret_event_register_any_= ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } =20 @@ -3387,7 +3387,7 @@ remoteConnectSecretEventDeregisterAny(virConnectPtr c= onn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this eventID, we need to disable @@ -3453,7 +3453,7 @@ remoteConnectDomainQemuMonitorEventRegister(virConnec= tPtr conn, (xdrproc_t) xdr_qemu_connect_domain_monitor_event_registe= r_args, (char *) &args, (xdrproc_t) xdr_qemu_connect_domain_monitor_event_registe= r_ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } virObjectEventStateSetRemote(conn, priv->eventState, callbackID, @@ -3485,7 +3485,7 @@ remoteConnectDomainQemuMonitorEventDeregister(virConn= ectPtr conn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this event, we need to disable @@ -4409,7 +4409,7 @@ remoteConnectDomainEventRegister(virConnectPtr conn, (xdrproc_t) xdr_remote_connect_domain_event_callback_= register_any_args, (char *) &args, (xdrproc_t) xdr_remote_connect_domain_event_callback_= register_any_ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } virObjectEventStateSetRemote(conn, priv->eventState, callbackI= D, @@ -4419,7 +4419,7 @@ remoteConnectDomainEventRegister(virConnectPtr conn, (xdrproc_t) xdr_void, (char *) NULL, (xdrproc_t) xdr_void, (char *) NULL) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } } @@ -4452,7 +4452,7 @@ remoteConnectDomainEventDeregister(virConnectPtr conn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 if (count =3D=3D 0) { @@ -5951,7 +5951,7 @@ remoteConnectDomainEventRegisterAny(virConnectPtr con= n, (xdrproc_t) xdr_remote_connect_domain_event_callback_= register_any_args, (char *) &args, (xdrproc_t) xdr_remote_connect_domain_event_callback_= register_any_ret, (char *) &ret) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } virObjectEventStateSetRemote(conn, priv->eventState, callbackI= D, @@ -5965,7 +5965,7 @@ remoteConnectDomainEventRegisterAny(virConnectPtr con= n, (xdrproc_t) xdr_remote_connect_domain_event_register_= any_args, (char *) &args, (xdrproc_t) xdr_void, (char *)NULL) =3D=3D -1) { virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID); + callbackID, true); goto done; } } @@ -5996,7 +5996,7 @@ remoteConnectDomainEventDeregisterAny(virConnectPtr c= onn, goto done; =20 if ((count =3D virObjectEventStateDeregisterID(conn, priv->eventState, - callbackID)) < 0) + callbackID, false)) < 0) goto done; =20 /* If that was the last callback for this eventID, we need to disable diff --git a/src/secret/secret_driver.c b/src/secret/secret_driver.c index fc01e6d..7d7ded8 100644 --- a/src/secret/secret_driver.c +++ b/src/secret/secret_driver.c @@ -532,7 +532,7 @@ secretConnectSecretEventDeregisterAny(virConnectPtr con= n, =20 if (virObjectEventStateDeregisterID(conn, driver->secretEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c index ab1dc8f..698654c 100644 --- a/src/storage/storage_driver.c +++ b/src/storage/storage_driver.c @@ -2662,7 +2662,7 @@ storageConnectStoragePoolEventDeregisterAny(virConnec= tPtr conn, =20 if (virObjectEventStateDeregisterID(conn, driver->storageEventState, - callbackID) < 0) + callbackID, false) < 0) goto cleanup; =20 ret =3D 0; diff --git a/src/test/test_driver.c b/src/test/test_driver.c index 11e7fd8..fec4d83 100644 --- a/src/test/test_driver.c +++ b/src/test/test_driver.c @@ -5697,7 +5697,7 @@ testConnectDomainEventDeregisterAny(virConnectPtr con= n, int ret =3D 0; =20 if (virObjectEventStateDeregisterID(conn, driver->eventState, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; =20 return ret; @@ -5731,7 +5731,7 @@ testConnectNetworkEventDeregisterAny(virConnectPtr co= nn, int ret =3D 0; =20 if (virObjectEventStateDeregisterID(conn, driver->eventState, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; =20 return ret; @@ -5764,7 +5764,7 @@ testConnectStoragePoolEventDeregisterAny(virConnectPt= r conn, int ret =3D 0; =20 if (virObjectEventStateDeregisterID(conn, driver->eventState, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; =20 return ret; @@ -5797,7 +5797,7 @@ testConnectNodeDeviceEventDeregisterAny(virConnectPtr= conn, int ret =3D 0; =20 if (virObjectEventStateDeregisterID(conn, driver->eventState, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; =20 return ret; diff --git a/src/uml/uml_driver.c b/src/uml/uml_driver.c index 080fea4..c3dc9d2 100644 --- a/src/uml/uml_driver.c +++ b/src/uml/uml_driver.c @@ -2721,7 +2721,7 @@ umlConnectDomainEventDeregisterAny(virConnectPtr conn, umlDriverLock(driver); if (virObjectEventStateDeregisterID(conn, driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; umlDriverUnlock(driver); =20 diff --git a/src/vz/vz_driver.c b/src/vz/vz_driver.c index 7aa0c4c..1fa2e2f 100644 --- a/src/vz/vz_driver.c +++ b/src/vz/vz_driver.c @@ -1053,7 +1053,7 @@ vzConnectDomainEventDeregisterAny(virConnectPtr conn, =20 if (virObjectEventStateDeregisterID(conn, privconn->driver->domainEventState, - callbackID) < 0) + callbackID, false) < 0) return -1; =20 return 0; diff --git a/src/xen/xen_driver.c b/src/xen/xen_driver.c index 8e7bc35..f6d7fdc 100644 --- a/src/xen/xen_driver.c +++ b/src/xen/xen_driver.c @@ -2284,7 +2284,7 @@ xenUnifiedConnectDomainEventDeregisterAny(virConnectP= tr conn, =20 if (virObjectEventStateDeregisterID(conn, priv->domainEvents, - callbackID) < 0) + callbackID, false) < 0) ret =3D -1; =20 xenUnifiedUnlock(priv); --=20 2.9.4 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list