[libvirt] [PATCH] qemu: Alter condition to avoid possible NULL deref

[Chen Hanxiao]

At 2018-02-09 23:33:38, "John Ferlan" <jferlan at redhat.com> wrote:
>Commit 'f0f2a5ec2' neglected to adjust the if condition to split
>out the possibility that the @watchdog is NULL when altering the
>message to add detail about the model.
>
>Just split out the condition and use previous/original message, but
>with the new message code.
>
>Found by Coverity
>
>Signed-off-by: John Ferlan <jferlan at redhat.com>
>---
> src/qemu/qemu_hotplug.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
>index c7bf25eee..3291ce613 100644
>--- a/src/qemu/qemu_hotplug.c
>+++ b/src/qemu/qemu_hotplug.c
>@@ -5159,11 +5159,16 @@ qemuDomainDetachWatchdog(virQEMUDriverPtr driver,
>     virDomainWatchdogDefPtr watchdog = vm->def->watchdog;
>     qemuDomainObjPrivatePtr priv = vm->privateData;
> 
>+    if (!watchdog) {
>+        virReportError(VIR_ERR_DEVICE_MISSING, "%s",
>+                       _("watchdog device not present in domain configuration"));
>+        return -1;
>+    }
>+
>     /* While domains can have up to one watchdog, the one supplied by the user
>      * doesn't necessarily match the one domain has. Refuse to detach in such
>      * case. */
>-    if (!(watchdog &&
>-          watchdog->model == dev->model &&
>+    if (!(watchdog->model == dev->model &&
>           watchdog->action == dev->action &&
>           virDomainDeviceInfoAddressIsEqual(&dev->info, &watchdog->info))) {
>         virReportError(VIR_ERR_DEVICE_MISSING,
>-- 

Reviewed-by: Chen Hanxiao <chenhanxiao at gmail.com>

Regards,
- Chen