[Freeipa-devel] [PATCH 0023] topology plugins sigsev when adding a managed host

[Ludwig Krispenz]

On 06/10/2016 05:41 PM, thierry bordaz wrote:
>
>
> On 06/10/2016 05:23 PM, Ludwig Krispenz wrote:
>>
>> On 06/10/2016 04:44 PM, thierry bordaz wrote:
>>> Hi Ludwig,
>>>
>>> I agree with you there is no path to add a host with an empty hostname.
>>> You fix looks valid but I would prefer a log in FATAL rather in PLUGIN.
>> yes, of course that was my intention, copy paste :-)
>>>
>>> Also I wonder if a reason of empty hostname could be a slapi_ch_free 
>>> on it but with the host remaining in the list.
>>> Looking at 
>>> https://git.fedorahosted.org/cgit/freeipa.git/tree/daemons/ipa-slapi-plugins/topology/topology_cfg.c#n852,
>>> I wonder if the two lines 852 and 853 could lead to this situation.
>> but this frees the complete replica structure tconf and in the caller 
>> tconf is set to null, so should never be used again.
>
> Yes you are right, it can not conduct to empty hostname into tconf.
> However I think it can leak because host will be set to 0 at the end 
> of the first iteration.
>
> An other possibility is that in
> https://git.fedorahosted.org/cgit/freeipa.git/tree/daemons/ipa-slapi-plugins/topology/topology_util.c#n1449|
> ipa_topo_util_init_hosts, 'cn' has an empty value. newhost is not null 
> but empty, so we may create an empty hostname.
> |

|newhost=  slapi_entry_attr_get_charptr(hostentry,"cn");
     if  (newhost==  NULL)  return;

if there is no cn, it will not be added, if the cn is an empty value, the pointer is not NULL and it will not crash when dereferncing
|



> ||
>>>
>>> thanks
>>> thierry
>>>
>>>
>>> On 06/10/2016 12:36 PM, Ludwig Krispenz wrote:
>>>> Hi,
>>>> the attached patch will prevent the crash reported in ticket #5928.
>>>>
>>>> So far I do not understand how this situation can occur, there is 
>>>> no reproducer yet. I do not really like this fix as it hides a 
>>>> probable corrupted data structure and would prefer to find the root 
>>>> cause.
>>>>
>>>> But please review it, so we can commit it if there is no progress 
>>>> on the root cause.
>>>>
>>>> Ludwig
>>>>
>>>>
>>>>
>>>
>>
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>

-- 
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Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Michael Cunningham, Michael O'Neill, Eric Shander

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