[libvirt] [PATCH] esx: avoid null dereference on error

[Matthias Bolte]

2011/5/4 Laine Stump <laine at laine.org>:
> On 05/03/2011 03:10 PM, Eric Blake wrote:
>>
>> Detected by clang.
>>
>> * src/esx/esx_driver.c (esxDomainGetInfo): Fail early on error.
>> ---
>>  src/esx/esx_driver.c |    1 +
>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c
>> index 1f8f90b..e929208 100644
>> --- a/src/esx/esx_driver.c
>> +++ b/src/esx/esx_driver.c
>> @@ -2372,8 +2372,9 @@ esxDomainGetInfo(virDomainPtr domain,
>> virDomainInfoPtr info)
>>
>>                  if (perfEntityMetric == NULL) {
>>                      VIR_ERROR(_("QueryPerf returned object with
>> unexpected type '%s'"),
>>
>>  esxVI_Type_ToString(perfEntityMetricBase->_type));
>> +                    goto cleanup;
>>                  }
>>
>>                  perfMetricIntSeries =
>>
>>  esxVI_PerfMetricIntSeries_DynamicCast(perfEntityMetric->value);
>
> I would just say ACK, since this obviously eliminates a null dereference,
> but I notice that the following check for perfMetricIntSeries == NULL also
> calls VIR_ERROR and then doesn't goto cleanup, so I'm wondering if maybe the
> intent is that if either of these is NULL, result should still get set to 0.
> Mathias?
>

NACK, as written.

There is a potential NULL dereference in there, but just going to
cleanup results in freeing static strings here. Patch 1 fixes it
correctly.

Actually this code has been there for a while now, but didn't do
anything useful with the queried values because of the format mismatch
between libvirt and ESX. Therefore, patch 2 disables that code but
keeps it as a reference for how to query performance counters.

Matthias
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