From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 E1B47C47404 for ; Fri, 11 Oct 2019 06:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF04E2196E for ; Fri, 11 Oct 2019 06:11:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=resnulli-us.20150623.gappssmtp.com header.i=@resnulli-us.20150623.gappssmtp.com header.b="Mc2YpNHQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727232AbfJKGLI (ORCPT ); Fri, 11 Oct 2019 02:11:08 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:38278 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726287AbfJKGLI (ORCPT ); Fri, 11 Oct 2019 02:11:08 -0400 Received: by mail-wm1-f68.google.com with SMTP id 3so8926137wmi.3 for ; Thu, 10 Oct 2019 23:11:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8nnHdbTQ16topfNyNvCbsM6+K1YLerkiNwgQ4142ujw=; b=Mc2YpNHQOWFIW4IjHMeujvyMfto0miF/ys2ftnO5wl6IlW4k1M5P/hgrU6QF+S+zne c6Q0jb1kdLTV8/wjXqKQ7ThP7kePqzQCf5emF+o3ZPpbnOGoXwOOIQ4X5m4VHjRhEsqR TuIY0oElP34DrB86M37i9Iu7BMeH2Y8hcGotJp5gSQ0eGKFkxqOAfoCWCi2nepDbZA7j VHMRVQu8ez9H3dpvpN8KzlJX3McvczI1g5xUKtLj9TZJShDHUenKhRE3KfmvxzV6rq0r ujqbClIcRYWHW0TqYcGvnErylMA5Q9MFf0Y1Z9NG+NRsROq4GA+TbCD5FTpWUBbncFeQ ByAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8nnHdbTQ16topfNyNvCbsM6+K1YLerkiNwgQ4142ujw=; b=lVWYmaTV68GpkWdMWi1DcAHfxkPDRWuuxPhK34h82u+lx6a/24It1bfPs3XTx2Ge1y KYZ5q2yv6n9vMuid8CdQKWcB8dMTgmN/CbGE/smkRt0x9a0WK/ppXa4gCQw0cON4ZMuH 3IBiJKfAKqEWTv5wKyMhP+Sk8VhotVkjl+M1kaGDQoJVc92PGNySpWOnVCJTsvOkHFU4 bx0z3Ye8BTOAy3/yoX5QK/tAiSugNUn3eQFN3PqpC9lbLejYfUS0kGINZDsOayk1Pelg PnbCv2fk/TEPuvR0KK/yhj3kQo27e8DCh7lrKScV/5mEVKIDYhi+tyRhz/T+JRHza0bG fAWw== X-Gm-Message-State: APjAAAWGui5A2aveGS4k5v4O19VPhRCoA9Dz2ysAFtr2ugavVtG7bhZe OhnZQCh9pLK56fZ1zIUnvYvaIg== X-Google-Smtp-Source: APXvYqzJmfJGGAPKwvnppyTzbfzLxh8vOPMMhMObO6CIiiO7HVL4AbgLA3hiYEFwpH+Q9aMHW9SiOQ== X-Received: by 2002:a7b:c44f:: with SMTP id l15mr1703059wmi.121.1570774266123; Thu, 10 Oct 2019 23:11:06 -0700 (PDT) Received: from localhost (jirka.pirko.cz. [84.16.102.26]) by smtp.gmail.com with ESMTPSA id m7sm9545306wrv.40.2019.10.10.23.11.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Oct 2019 23:11:05 -0700 (PDT) Date: Fri, 11 Oct 2019 08:11:05 +0200 From: Jiri Pirko To: Jakub Kicinski Cc: Michal Kubecek , "David S. Miller" , Jiri Pirko , Johannes Berg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v2] genetlink: do not parse attributes for families with zero maxattr Message-ID: <20191011061105.GF2901@nanopsycho> References: <20191010103402.36408E378C@unicorn.suse.cz> <20191010102102.3bc8515d@cakuba.netronome.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191010102102.3bc8515d@cakuba.netronome.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thu, Oct 10, 2019 at 07:21:02PM CEST, jakub.kicinski@netronome.com wrote: >On Thu, 10 Oct 2019 12:34:02 +0200 (CEST), Michal Kubecek wrote: >> Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing >> to a separate function") moved attribute buffer allocation and attribute >> parsing from genl_family_rcv_msg_doit() into a separate function >> genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls >> __nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own >> parsing). The parser error is ignored and does not propagate out of >> genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute >> type") is set in extack and if further processing generates no error or >> warning, it stays there and is interpreted as a warning by userspace. >> >> Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses >> the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the >> same also in genl_family_rcv_msg_doit(). >> >> Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function") >> Signed-off-by: Michal Kubecek >> --- >> net/netlink/genetlink.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c >> index ecc2bd3e73e4..1f14e55ad3ad 100644 >> --- a/net/netlink/genetlink.c >> +++ b/net/netlink/genetlink.c >> @@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family, >> const struct genl_ops *ops, >> int hdrlen, struct net *net) >> { >> - struct nlattr **attrbuf; >> + struct nlattr **attrbuf = NULL; >> struct genl_info info; >> int err; >> >> if (!ops->doit) >> return -EOPNOTSUPP; >> >> + if (!family->maxattr) >> + goto no_attrs; >> attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, >> ops, hdrlen, >> GENL_DONT_VALIDATE_STRICT, >> - family->maxattr && >> family->parallel_ops); >> if (IS_ERR(attrbuf)) >> return PTR_ERR(attrbuf); >> >> +no_attrs: > >The use of a goto statement as a replacement for an if is making me >uncomfortable. > >Looks like both callers of genl_family_rcv_msg_attrs_parse() jump >around it if !family->maxattr and then check the result with IS_ERR(). > >Would it not make more sense to have genl_family_rcv_msg_attrs_parse() >return NULL if !family->maxattr? Okay. Sounds fine to me. > >Just wondering, if you guys prefer this version I can apply.. > >> info.snd_seq = nlh->nlmsg_seq; >> info.snd_portid = NETLINK_CB(skb).portid; >> info.nlhdr = nlh; >> @@ -676,8 +678,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family, >> family->post_doit(ops, skb, &info); >> >> out: >> - genl_family_rcv_msg_attrs_free(family, attrbuf, >> - family->maxattr && family->parallel_ops); >> + genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops); >> >> return err; >> }