[libvirt] [PATCH] audit: eliminate potential null pointer deref when auditing macvtap devices

[Laine Stump]

On 03/14/2011 11:25 AM, Eric Blake wrote:
> On 03/14/2011 09:18 AM, Laine Stump wrote:
>> The newly added call to qemuAuditNetDevice in qemuPhysIfaceConnect was
>> assuming that res_ifname (the name of the macvtap device) was always
>> valid, but this isn't the case. If openMacvtapTap fails, it always
>> returns NULL, which would result in a segv.
>>
>> Since the audit log only needs a record of devices that are actually
>> sent to qemu, and a failure to open the macvtap device means that no
>> device will be sent to qemu, we can solve this problem by only doing
>> the audit if openMacvtapTap is successful (in which case res_ifname is
>> guaranteed valid).
>> ---
>>   src/qemu/qemu_command.c |    2 +-
>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>> index 8ca656a..72f55d0 100644
>> --- a/src/qemu/qemu_command.c
>> +++ b/src/qemu/qemu_command.c
>> @@ -128,8 +128,8 @@ qemuPhysIfaceConnect(virDomainDefPtr def,
>>                           net->data.direct.mode, vnet_hdr, def->uuid,
>>                           &net->data.direct.virtPortProfile,&res_ifname,
>>                           vmop);
>> -    qemuAuditNetDevice(def, net, res_ifname, rc>= 0);
>>       if (rc>= 0) {
>> +        qemuAuditNetDevice(def, net, res_ifname, true);
>>           VIR_FREE(net->ifname);
>>           net->ifname = res_ifname;
>>       }
> ACK.
>

Pushed. Thanks!