On 09/17/2014 10:25 AM, Peter Krempa wrote:
Live definition was used to look up the disk index while persistent
one
was indexed leading to a crash in qemuDomainGetBlockIoTune. Use the
correct def and report a nice error.
Unfortunately it's accessible via read-only connection.
Mitigation - a read-only connection can only crash libvirtd in the cases
where the guest is hot-plugging disks without reflecting those changes
to the persistent definition. So avoiding hotplug, or doing hotplug
where persistent is always modified alongside live definition, will
avoid the out-of-bounds access.
Introduced in: eca96694a7f992be633d48d5ca03cedc9bbc3c9aa (v0.9.8)
Resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=1140724
Reported-by: Luyao Huang <lhuang(a)redhat.com>
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
src/qemu/qemu_driver.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
ACK. I can write up the libvirt security notice; we'll eventually need
this backported to all the affected maint branches. I'll coordinate the
backport effort with you on IRC.
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a5a49ac..209c40e 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -16317,9 +16317,13 @@ qemuDomainGetBlockIoTune(virDomainPtr dom,
}
if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
- int idx = virDomainDiskIndexByName(vm->def, disk, true);
- if (idx < 0)
+ int idx = virDomainDiskIndexByName(persistentDef, disk, true);
+ if (idx < 0) {
+ virReportError(VIR_ERR_INVALID_ARG,
+ _("disk '%s' was not found in the domain
config"),
+ disk);
goto endjob;
+ }
reply = persistentDef->disks[idx]->blkdeviotune;
}
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library
http://libvirt.org