[PATCH] libvirt-remote:fix use-after-free when sending event message

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From 6b42792cfee124a742999e698e348e99b382ba16 Mon Sep 17 00:00:00 2001

From: c00207022 <caoxinhua@xxxxxxxxxx>

Date: Thu, 2 Mar 2017 12:07:27 +0800

Subject: [PATCH] libvirt-remote:fix use-after-free when sending event message

 

[Changelog]:If there is a process with a client which registers event callbacks,

and it calls libvirt's API which uses the same virConnectPtr in that

callback function. When this process exit abnormally lead to client

disconnect, there is a possibility that the libvirtd's main thread is use

virServerClient to send event just after the virServerClient been freed by job

thread.

Following is backtrace:

 

#0  0x00007fda223d66d8 in virClassIsDerivedFrom (klass=0xdeadbeef, parent=0x7fda24c81b40) at util/virobject.c:169

#1  0x00007fda223d6a1e in virObjectIsClass (anyobj=anyobj@entry=0x7fd9e575b400, klass=<optimized out>) at util/virobject.c:365

#2  0x00007fda223d6a44 in virObjectLock (anyobj=0x7fd9e575b400) at util/virobject.c:317

#3  0x00007fda22507f71 in virNetServerClientSendMessage (client=client@entry=0x7fd9e575b400, msg=msg@entry=0x7fd9ec30de90)

at rpc/virnetserverclient.c:1422

#4  0x00007fda230d714d in remoteDispatchObjectEventSend (client=0x7fd9e575b400, program=0x7fda24c844e0, procnr=348,

proc=0x7fda2310e5e0 <xdr_remote_domain_event_callback_tunable_msg>, data="" at remote.c:3803

#5  0x00007fda230dd71b in remoteRelayDomainEventTunable (conn=<optimized out>, dom=0x7fda27cd7660, params=0x7fda27f3aae0, nparams=1,

opaque=0x7fd9e6c99e00) at remote.c:1033

#6  0x00007fda224484cb in virDomainEventDispatchDefaultFunc (conn=0x7fda27cd0120, event=0x7fda2736ea00,

cb=0x7fda230dd610 <remoteRelayDomainEventTunable>, cbopaque=0x7fd9e6c99e00) at conf/domain_event.c:1910

#7  0x00007fda22446871 in virObjectEventStateDispatchCallbacks (callbacks=<optimized out>, callbacks=<optimized out>, event=0x7fda2736ea00,

state=0x7fda24ca3960) at conf/object_event.c:722

#8  virObjectEventStateQueueDispatch (callbacks=0x7fda24c65800, queue=0x7ffc3857fe90, state=0x7fda24ca3960) at conf/object_event.c:736

#9  virObjectEventStateFlush (state=0x7fda24ca3960) at conf/object_event.c:814

#10 virObjectEventTimer (timer=<optimized out>, opaque=0x7fda24ca3960) at conf/object_event.c:560

#11 0x00007fda223ae8b9 in virEventPollDispatchTimeouts () at util/vireventpoll.c:458

#12 virEventPollRunOnce () at util/vireventpoll.c:654

#13 0x00007fda223ad1d2 in virEventRunDefaultImpl () at util/virevent.c:314

#14 0x00007fda225046cd in virNetDaemonRun (dmn=0x7fda24c775c0) at rpc/virnetdaemon.c:818

#15 0x00007fda230d6351 in main (argc=<optimized out>, argv=<optimized out>) at libvirtd.c:1623

 

Let's clean all event callback when client close.

 

Signed-off-by: Caoxinhua <caoxinhua@xxxxxxxxxx>

---

daemon/remote.c | 76 +++++++++++++++++++++------------------------------------

1 file changed, 28 insertions(+), 48 deletions(-)

 

diff --git a/daemon/remote.c b/daemon/remote.c

index 23c9de4..fb7cd50 100644

--- a/daemon/remote.c

+++ b/daemon/remote.c

@@ -101,6 +101,7 @@ static void make_nonnull_node_device(remote_nonnull_node_device *dev_dst, virNod

static void make_nonnull_secret(remote_nonnull_secret *secret_dst, virSecretPtr secret_src);

static void make_nonnull_nwfilter(remote_nonnull_nwfilter *net_dst, virNWFilterPtr nwfilter_src);

static void make_nonnull_domain_snapshot(remote_nonnull_domain_snapshot *snapshot_dst, virDomainSnapshotPtr snapshot_src);

+static void remoteClientCleanEventCallbacks(struct daemonClientPrivate *priv);

 static int

remoteSerializeDomainDiskErrors(virDomainDiskErrorPtr errors,

@@ -1483,24 +1484,15 @@ void remoteRelayConnectionClosedEvent(virConnectPtr conn ATTRIBUTE_UNUSED, int r

                                   &msg);

}

-/*

- * You must hold lock for at least the client

- * We don't free stuff here, merely disconnect the client's

- * network socket & resources.

- * We keep the libvirt connection open until any async

- * jobs have finished, then clean it up elsewhere

- */

-void remoteClientFreeFunc(void *data)

+static void remoteClientCleanEventCallbacks(struct daemonClientPrivate *priv)

{

-    struct daemonClientPrivate *priv = data;

-

     /* Deregister event delivery callback */

-    if (priv->conn) {

-        virIdentityPtr sysident = virIdentityGetSystem();

+    if (priv && priv->conn) {

         size_t i;

-

+        virIdentityPtr sysident = virIdentityGetSystem();

         virIdentitySetCurrent(sysident);

+        virMutexLock(&priv->lock);

         for (i = 0; i < priv->ndomainEventCallbacks; i++) {

             int callbackID = priv->domainEventCallbacks[i]->callbackID;

             if (callbackID < 0) {

@@ -1514,6 +1506,7 @@ void remoteClientFreeFunc(void *data)

                 VIR_WARN("unexpected domain event deregister failure");

         }

         VIR_FREE(priv->domainEventCallbacks);

+        priv->ndomainEventCallbacks = 0;

         for (i = 0; i < priv->nnetworkEventCallbacks; i++) {

             int callbackID = priv->networkEventCallbacks[i]->callbackID;

@@ -1529,36 +1522,7 @@ void remoteClientFreeFunc(void *data)

                 VIR_WARN("unexpected network event deregister failure");

         }

         VIR_FREE(priv->networkEventCallbacks);

-

-        for (i = 0; i < priv->nstorageEventCallbacks; i++) {

-            int callbackID = priv->storageEventCallbacks[i]->callbackID;

-            if (callbackID < 0) {

-                VIR_WARN("unexpected incomplete storage pool callback %zu", i);

-                continue;

-            }

-            VIR_DEBUG("Deregistering remote storage pool event relay %d",

-                      callbackID);

-            priv->storageEventCallbacks[i]->callbackID = -1;

-            if (virConnectStoragePoolEventDeregisterAny(priv->conn,

-                                                        callbackID) < 0)

-                VIR_WARN("unexpected storage pool event deregister failure");

-        }

-        VIR_FREE(priv->storageEventCallbacks);

-

-        for (i = 0; i < priv->nnodeDeviceEventCallbacks; i++) {

-            int callbackID = priv->nodeDeviceEventCallbacks[i]->callbackID;

-            if (callbackID < 0) {

-                VIR_WARN("unexpected incomplete node device callback %zu", i);

-                continue;

-            }

-            VIR_DEBUG("Deregistering remote node device event relay %d",

-                      callbackID);

-            priv->nodeDeviceEventCallbacks[i]->callbackID = -1;

-            if (virConnectNodeDeviceEventDeregisterAny(priv->conn,

-                                                       callbackID) < 0)

-                VIR_WARN("unexpected node device event deregister failure");

-        }

-        VIR_FREE(priv->nodeDeviceEventCallbacks);

+        priv->nnetworkEventCallbacks = 0;

         for (i = 0; i < priv->nqemuEventCallbacks; i++) {

             int callbackID = priv->qemuEventCallbacks[i]->callbackID;

@@ -1574,31 +1538,47 @@ void remoteClientFreeFunc(void *data)

                 VIR_WARN("unexpected qemu monitor event deregister failure");

         }

         VIR_FREE(priv->qemuEventCallbacks);

+        priv->nqemuEventCallbacks = 0;

         if (priv->closeRegistered) {

             if (virConnectUnregisterCloseCallback(priv->conn,

                                                   remoteRelayConnectionClosedEvent) < 0)

                 VIR_WARN("unexpected close callback event deregister failure");

         }

-

-        virConnectClose(priv->conn);

-

+        virMutexUnlock(&priv->lock);

         virIdentitySetCurrent(NULL);

         virObjectUnref(sysident);

     }

+}

+

+

+/*

+ * You must hold lock for at least the client

+ * We don't free stuff here, merely disconnect the client's

+ * network socket & resources.

+ * We keep the libvirt connection open until any async

+ * jobs have finished, then clean it up elsewhere

+ */

+void remoteClientFreeFunc(void *data)

+{

+    struct daemonClientPrivate *priv = data;

+    if (!priv || !priv->conn)

+        return;

+

+    remoteClientCleanEventCallbacks(priv);

+    virConnectClose(priv->conn);

     VIR_FREE(priv);

}

-

static void remoteClientCloseFunc(virNetServerClientPtr client)

{

     struct daemonClientPrivate *priv = virNetServerClientGetPrivateData(client);

     daemonRemoveAllClientStreams(priv->streams);

+    remoteClientCleanEventCallbacks(priv);

}

-

void *remoteClientInitHook(virNetServerClientPtr client,

                            void *opaque ATTRIBUTE_UNUSED)

{

--

1.8.3.1

 

 

 

Attachment: 0001-libvirt-remote-fix-use-after-free-when-sending-event.patch
Description: 0001-libvirt-remote-fix-use-after-free-when-sending-event.patch

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