Issue 50829 - Disk monitoring rotated log cleanup causes heap-use-aft…

…er-free

Description:  When Disk Monitoring finds that disk space is too low it starts
              freeing up disk space by removing rotated logs.  However the log
              list struct was not properly reset after freeing all the files
              in the list.  This is what allowed the heap-use-after-free to
              occur.

relates: https://pagure.io/389-ds-base/issue/50829

Reviewed by: firstyear(Thanks!)

ldap/servers/slapd/log.c

@@ -3243,6 +3243,12 @@ log__delete_rotated_logs()
         logp = logp->l_next;
         slapi_ch_free((void **)&prev_log);
     }
+
+    /* reset the log struct */
+    loginfo.log_access_logchain = NULL;
+    loginfo.log_audit_logchain = NULL;
+    loginfo.log_auditfail_logchain = NULL;
+    loginfo.log_error_logchain = NULL;
 }
 
 #define ERRORSLOG 1