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=-4.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 12375C2D0A8 for ; Mon, 28 Sep 2020 23:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA29820719 for ; Mon, 28 Sep 2020 23:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601335840; bh=USpniiZPSjX9PvCc27mG/IIV3bgaeRYXivPfC1sKaCs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=FBukXcMJO4wB2ie1uc2dzrBbjlE3iPMgAutoEzMhbzoUEC0K+uifz9atctOQWzcQw O2//NlUedq1N+j6vdAL8ptzgfOnHFEWjhsLu5MVlRZbFFdFIeYvlGVKnousDHNF8/J uI83zl4OLTUIz7khSgRv11U3jcX9mRdd+EWU1zSc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727194AbgI1Xaj (ORCPT ); Mon, 28 Sep 2020 19:30:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:53612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727125AbgI1Xac (ORCPT ); Mon, 28 Sep 2020 19:30:32 -0400 Received: from sol.localdomain (172-10-235-113.lightspeed.sntcca.sbcglobal.net [172.10.235.113]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 49BCC22262; Mon, 28 Sep 2020 22:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601331283; bh=USpniiZPSjX9PvCc27mG/IIV3bgaeRYXivPfC1sKaCs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=1JPJAa2M8r1+Kmgu2TUoUpoIUzu0X8/iCW/FXrJ+a3Jd9Id4x5d0wHUS5KczOFfSG QGLKMegDqCV2jarOmBu7voR1a+2TJpmbBMMDVHhg1BiqwC5DXIDA8GEGrd08lKzHli Ydn4a/Qdlc/puyb39pAQ58QzsjRekS18hTo6EzSA= Date: Mon, 28 Sep 2020 15:14:41 -0700 From: Eric Biggers To: Christoph Hellwig Cc: David Laight , syzbot+51177e4144d764827c45@syzkaller.appspotmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: WARNING in __kernel_read (2) Message-ID: <20200928221441.GF1340@sol.localdomain> References: <000000000000da992305b02e9a51@google.com> <3b3de066852d4e30bd9d85bd28023100@AcuMS.aculab.com> <642ed0b4810d44ab97a7832ccb8b3e44@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <642ed0b4810d44ab97a7832ccb8b3e44@AcuMS.aculab.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 26, 2020 at 01:17:04PM +0000, David Laight wrote: > From: David Laight > > Sent: 26 September 2020 12:16 > > To: 'syzbot' ; linux-fsdevel@vger.kernel.org; > > linux-kernel@vger.kernel.org; syzkaller-bugs@googlegroups.com; viro@zeniv.linux.org.uk > > Subject: RE: WARNING in __kernel_read (2) > > > > > From: syzbot > > > Sent: 26 September 2020 03:58 > > > To: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; syzkaller-bugs@googlegroups.com; > > > viro@zeniv.linux.org.uk > > > Subject: WARNING in __kernel_read (2) > > > > I suspect this is calling finit_module() on an fd > > that doesn't have read permissions. > > Code inspection also seems to imply that the check means > the exec() also requires read permissions on the file. > > This isn't traditionally true. > suid #! scripts are particularly odd without 'owner read' > (everyone except the owner can run them!). Christoph, any thoughts here? You added this WARN_ON_ONCE in: commit 61a707c543e2afe3aa7e88f87267c5dafa4b5afa Author: Christoph Hellwig Date: Fri May 8 08:54:16 2020 +0200 fs: add a __kernel_read helper