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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 B64B7C4338F for ; Sat, 14 Aug 2021 15:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 898106101E for ; Sat, 14 Aug 2021 15:37:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238699AbhHNPha (ORCPT ); Sat, 14 Aug 2021 11:37:30 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:50054 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234654AbhHNPha (ORCPT ); Sat, 14 Aug 2021 11:37:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=sQ+X1nOHW0Y0aKmJBa2mRiazMXs7QZuokAPbxAsRxD8=; b=CXjZYPd1IemzfTg8ePhC5u+qAZ DMCZ7sDD/HiJ5Bzd7wpXV5whRszPhza9An+wS0GMnysZPWmrk453W03AqviTRhhC00uCG+TwPA+jf SzziaMxz8SY1gdR6LGuA4Rkr+qZEI8jrZ4N9k0x9gpaU60jowtWlvKLeS7csl5HrXRO0=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1mEviQ-00050a-RI; Sat, 14 Aug 2021 17:36:54 +0200 Date: Sat, 14 Aug 2021 17:36:54 +0200 From: Andrew Lunn To: Pavel Skripkin Cc: davem@davemloft.net, kuba@kernel.org, linux@rempel-privat.de, robert.foss@collabora.com, linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+a631ec9e717fb0423053@syzkaller.appspotmail.com Subject: Re: [PATCH v3] net: asix: fix uninit value bugs Message-ID: References: <20210813155226.651c74f0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210814135505.11920-1-paskripkin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210814135505.11920-1-paskripkin@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Sat, Aug 14, 2021 at 04:55:05PM +0300, Pavel Skripkin wrote: > Syzbot reported uninit-value in asix_mdio_read(). The problem was in > missing error handling. asix_read_cmd() should initialize passed stack > variable smsr, but it can fail in some cases. Then while condidition > checks possibly uninit smsr variable. > > Since smsr is uninitialized stack variable, driver can misbehave, > because smsr will be random in case of asix_read_cmd() failure. > Fix it by adding error handling and just continue the loop instead of > checking uninit value. > > Also, same loop was used in 3 other functions. Fixed uninit value bug > in them too. Hi Pavel Which suggests it might make sense to refactor the code to make a helper? I will leave you to decide if you want to do that. The code does looks correct now. Andrew