Re: (ITS#8660) slapd segmentation faults (relay backend and rwm overlay)

[hyc@symas.com]

nespor@id.ethz.ch wrote:
> Full_Name: Vlado Nespor
> Version: 2.4.44
> OS: Red Hat el7
> URL: ftp://ftp.openldap.org/incoming/
> Submission from: (NULL) (2001:67c:10ec:32d0::222)
>
>
> We have experienced random slapd segmentation faults, when the relay
> backend and rwm overlay were used in the configuration. After some
> time I could reproduce the segmentation fault on a slow client and
> with test queries, which were supposed to return a larger set of entries.
>
> I could trace the problem to a wrong pointer in the slap_writewait_play
> function in the openldap-2.4.44/servers/slapd/result.c file, and then
> further to the openldap-2.4.44/servers/slapd/back-relay/op.c file. After
> the addition of the sc_writewait pointer initialisation (see the patch
> below), the test queries returned correct results and random slapd
> segmentation faults disappeared.

Thanks for the report, but this was already fixed in ITS#8218 released in 
2.4.43. Sounds like Red Hat has botched their source code since the official 
fix has been out for nearly 2 years already.
>
> With best regards,
>
> Vlado Nespor
>
>
> diff -rupN openldap-2.4.44/servers/slapd/back-relay/op.c
> openldap-2.4.44_back-relay/servers/slapd/back-relay/op.c
> --- openldap-2.4.44/servers/slapd/back-relay/op.c	2016-02-06 00:57:45.000000000
> +0100
> +++ openldap-2.4.44_back-relay/servers/slapd/back-relay/op.c	2017-02-07
> 15:09:55.046188340 +0100
> @@ -97,6 +97,7 @@ relay_back_response_cb( Operation *op, S
>  		(rcb)->rcb_sc.sc_next = (op)->o_callback;	\
>  		(rcb)->rcb_sc.sc_response = relay_back_response_cb; \
>  		(rcb)->rcb_sc.sc_cleanup = 0;			\
> +		(rcb)->rcb_sc.sc_writewait = 0;			\
>  		(rcb)->rcb_sc.sc_private = (op)->o_bd;		\
>  		(op)->o_callback = (slap_callback *) (rcb);	\
>  }
>
>
>


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