From patchwork Tue Oct 6 18:15:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 11819137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47F65C41604 for ; Tue, 6 Oct 2020 18:16:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1C0820760 for ; Tue, 6 Oct 2020 18:16:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726762AbgJFSQE (ORCPT ); Tue, 6 Oct 2020 14:16:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbgJFSQD (ORCPT ); Tue, 6 Oct 2020 14:16:03 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE6FEC061755 for ; Tue, 6 Oct 2020 11:16:03 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94) (envelope-from ) id 1kPrVK-000PRR-1J; Tue, 06 Oct 2020 20:16:02 +0200 From: Johannes Berg To: netdev@vger.kernel.org Cc: dsahern@gmail.com, Jakub Kicinski Subject: [PATCH v2 0/2] netlink: export policy on validation failures Date: Tue, 6 Oct 2020 20:15:53 +0200 Message-Id: <20201006181555.103140-1-johannes@sipsolutions.net> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Export the policy used for attribute validation when it fails, so e.g. for an out-of-range attribute userspace immediately gets the valid ranges back. v2 incorporates the suggestion from Jakub to have a function to estimate the size (netlink_policy_dump_attr_size_estimate()) and check that it does the right thing on the *normal* policy dumps, not (just) when calling it from the error scenario. Tested using nl80211/iw in a few scenarios, seems to work fine and return the policy back, e.g. kernel reports: integer out of range policy: 04 00 0b 00 0c 00 04 00 01 00 00 00 00 00 00 00 ^ padding ^ minimum allowed value policy: 04 00 0b 00 0c 00 05 00 ff ff ff ff 00 00 00 00 ^ padding ^ maximum allowed value policy: 08 00 01 00 04 00 00 00 ^ type 4 == U32 for an out-of-range case. johannes Reviewed-by: Jakub Kicinski