From 938ef6e611b39630b00b368b8b8d7db7e619ed99 Mon Sep 17 00:00:00 2001
From: Jiri Denemark <jdenemar@redhat.com>
Date: Thu, 19 Dec 2013 22:10:04 +0100
Subject: [PATCH] qemu: Do not access stale data in virDomainBlockStats
CVE-2013-6458
https://bugzilla.redhat.com/show_bug.cgi?id=1043069
When virDomainDetachDeviceFlags is called concurrently to
virDomainBlockStats: libvirtd may crash because qemuDomainBlockStats
finds a disk in vm->def before getting a job on a domain and uses the
disk pointer after getting the job. However, the domain in unlocked
while waiting on a job condition and thus data behind the disk pointer
may disappear. This happens when thread 1 runs
virDomainDetachDeviceFlags and enters monitor to actually remove the
disk. Then another thread starts running virDomainBlockStats, finds the
disk in vm->def, and while it's waiting on the job condition (owned by
the first thread), the first thread finishes the disk removal. When the
second thread gets the job, the memory pointed to be the disk pointer is
already gone.
That said, every API that is going to begin a job should do that before
fetching data from vm->def.
(cherry picked from commit db86da5ca2109e4006c286a09b6c75bfe10676ad)
Conflicts:
src/qemu/qemu_driver.c - context: no ACLs
---
src/qemu/qemu_driver.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index ecd3b08f9e..26ba19dbd6 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8524,34 +8524,29 @@ qemuDomainBlockStats(virDomainPtr dom,
if (!(vm = qemuDomObjFromDomain(dom)))
goto cleanup;
+ if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
+ goto cleanup;
+
if (!virDomainObjIsActive(vm)) {
virReportError(VIR_ERR_OPERATION_INVALID,
"%s", _("domain is not running"));
- goto cleanup;
+ goto endjob;
}
if ((i = virDomainDiskIndexByName(vm->def, path, false)) < 0) {
virReportError(VIR_ERR_INVALID_ARG,
_("invalid path: %s"), path);
- goto cleanup;
+ goto endjob;
}
disk = vm->def->disks[i];
if (!disk->info.alias) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("missing disk device alias name for %s"), disk->dst);
- goto cleanup;
+ goto endjob;
}
priv = vm->privateData;
- if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
- goto cleanup;
-
- if (!virDomainObjIsActive(vm)) {
- virReportError(VIR_ERR_OPERATION_INVALID,
- "%s", _("domain is not running"));
- goto endjob;
- }
qemuDomainObjEnterMonitor(driver, vm);
ret = qemuMonitorGetBlockStatsInfo(priv->mon,
--
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