possible null pointer dereference in qemuDomainPinEmulator()

[Chris Friesen]

In src/qemu/qemu_driver.c the qemuDomainPinEmulator() routine basically does this

     virDomainObjPtr vm;

     if (!(vm = qemuDomObjFromDomain(dom)))
         goto cleanup;

cleanup:
     qemuDomObjEndAPI(&vm);

If "vm" is null, then this will crash.

The bug seems to have been added in commit 540c339a, which removed a null pointer check:
- if (vm)
- virObjectUnlock(vm);
+ qemuDomObjEndAPI(&vm);

[Chris Friesen (cbf123)]

Thanks Eric...must have been a brain fart. :)

[Serge Hallyn (serge-hallyn)]

Hm,

if vm is null, then at cleanup we do

qemuDomObjEndAPI(&vm);

then qemuDomObjEndAPI checks:

if (!*vm)
   return;

Perhaps it's too late in the day for me, but this looks ok?

[Chris Friesen (cbf123)]

Okay, so apparently I'm blind. Yeah, code looks fine.

The original thing that had me thinking this was buggy is that I'm seeing libvirtd crash if I run 'virsh emulatorpin'. Will try and isolate further and open a different bug report if appropriate.