Bug 630097 - (cov#15509) NULL dereference in idsktune

If strdup() fails, the cmd variable will be NULL.  We dereference
it without checking it strdup() was successful.  We should check
if cmd is NULL before dereferencing it.

ldap/systools/idsktune.c

@@ -1108,6 +1108,11 @@ linux_check_release(void)
   char osl[128];
   char *cmd = strdup("/bin/uname -r");
 
+  if (cmd == NULL) {
+    printf("ERROR: Unable to allocate memory\n");
+    goto done;
+  }
+
   if (flag_html) printf("<P>\n");
   if (flag_debug) printf("DEBUG  : %s\n",cmd);
   fp = popen(cmd,"r");