Re: (ITS#8064) SIGSEGV in monitor-shutdown code

[hyc@symas.com]

pierangelo.masarati@polimi.it wrote:
> back-monitor was designed before back-config, without considering the
> possibility of database removal during regular operations.  There might
> be several flaws of that kind.

Removal is not supported in 2.4. All of that is work-in-progress for 2.5. Patches welcome, but this is not a 2.4 bug.

> My suggestion is that back-monitor is never shut down (it should be
> inhibited) except at slapd shutdown.  Meanwhile, the code initialization
> and shutdown could be redesigned to properly handle those cases.
>
> On 25/02/2015 15:18, leo@yuriev.ru wrote:
>> Full_Name: Leonid Yuriev
>> Version: 2.4-HEAD
>> OS: RHEL7
>> URL: ftp://ftp.openldap.org/incoming/
>> Submission from: (NULL) (31.130.36.33)
>>
>>
>> Monitor-backend shutdown code could call a callback from registered subsystem
>> after it is already destroyed.
>>
>> For instance, currently ldap-backend frees its own registered context (lmi_mss
>> from ldap_monitor_info_t) before than monitor_back_db_destroy() will be called.
>>
>> Therefore SIGSEGV would be occur on monitor shutdown if any ldap-backend
>> database is configured and such freed context will be overwrited.
>>
>> This bug could be reproduced by a filling-memory-with-non-zero before calling
>> free() from glibc.
>>
>>
>>
>
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/