[libvirt] [PATCH] Avoid segv if ncf_init fails

[Laine Stump]

On 10/27/2009 10:28 AM, David Lutterkort wrote:
> On Tue, 2009-10-27 at 14:23 +0000, David Lutterkort wrote:
>    
>> On Fri, 2009-10-23 at 20:31 +0100, Daniel P. Berrange wrote:
>>      
>>> On Fri, Oct 23, 2009 at 03:13:17PM -0400, Laine Stump wrote:
>>>        
>>>> If ncf_init() fails, it takes responsibility to call ncf_close() when
>>>> appropriate. Having libvirt call it results in a double close, which
>>>> ends up segv'ing.
>>>>          
>>> Hmm, it would be good if ncf_init  set the passed in pointer to NULL
>>> when it failed, then your existing cleanup check would have been
>>> safe.
>>>        
>> Agreed - that that doesn't happen was an oversight. I'll fix that.
>>      
> Spoke too soon - ncf_init returns -2 when allocations fail so badly that
> we can't even allocate the struct netcf (in which case ncf_init should
> reset the pointer to NULL, but doesn't - that's the bug that needs to be
> addressed)
>
> It can also return -1 for all kinds of other failures; in that case you
> have a struct netcf that's good enough to pass to ncf_error to get more
> error details.
>    


Hmm. I guess I should setup my error scenario again and see if it was 
returning -2 - it was pretty simple to reproduce, I would just run 
libvirtd as non-root and connect to it with virsh.

If it was returning -2. I'll send a new patch for libvirt that, if the 
return is -1, retrieves the extra error stuff and reports it, then does 
ncf_close().
> David
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