Segmentation fault when nebmodule returns with something else than 0

[Tobias Mucke]

Hi list,

found the problem, at least I think to have found the problem.
Actually function neb_set_module_info does not operate on the
nebmodule struct but on the mod_handle it got from its caller. The
latter is from type lt_dlhandle. To set an info of type
NEBMODULE_MODINFO_* does not make sense.
Two problems arose by this and I fall into both. Writing informations
to the module by neb_set_module_info works for some of the
NEBMODULE_MODINFO_*. Some other lead to a segfault. The second problem
is, if you have overwritten the NEBMODULE_MODINFO_TITLE you overwrite
the filename of the lt_dlhandle and the module can't be unloaded
anymore.

I have written a patch. Since I am not a very experienced C programmer
please review it carefully before applying to official Nagios code.



--- nagios-3.0b7/base/nebmods.c 2007-10-22 15:39:30.000000000 +0200
+++ nagios-3.0b7-mod/base/nebmods.c     2007-11-27 07:35:52.000000000 +0100
@@ -338,24 +338,29 @@
 /****************************************************************************/

 /* sets module information */
-int neb_set_module_info(void *handle, int type, char *data){
-       nebmodule *mod=NULL;
+int neb_set_module_info(void *mod_handle, int type, char *data){
+       nebmodule *temp_module = NULL;

-       if(handle==NULL)
+       if(mod_handle==NULL)
                return NEBERROR_NOMODULE;

        /* check type */
        if(type<0 || type>=NEBMODULE_MODINFO_NUMITEMS)
                return NEBERROR_MODINFOBOUNDS;

-       /* get the module */
-       mod=(nebmodule *)handle;
+       /* find corresponding nebmodule */
+       for(temp_module=neb_module_list;temp_module;temp_module=temp_module->next){
+               if((void *)temp_module->module_handle == (void *)mod_handle)
+                       break;
+       }
+       if(temp_module==NULL)
+               return NEBERROR_BADMODULEHANDLE;

        /* free any previously allocated memory */
-       my_free(mod->info[type]);
+       my_free(temp_module->info[type]);

        /* allocate memory for the new data */
-       if((mod->info[type]=(char *)strdup(data))==NULL)
+       if((temp_module->info[type]=(char *)strdup(data))==NULL)
                return NEBERROR_NOMEM;

        return OK;


Thanks.

Tobias
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