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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8CCE3C432BE for ; Thu, 26 Aug 2021 19:44:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 715B460F4C for ; Thu, 26 Aug 2021 19:44:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243360AbhHZTpi (ORCPT ); Thu, 26 Aug 2021 15:45:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243339AbhHZTph (ORCPT ); Thu, 26 Aug 2021 15:45:37 -0400 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E76F3C061757 for ; Thu, 26 Aug 2021 12:44:49 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id lc21so8727801ejc.7 for ; Thu, 26 Aug 2021 12:44:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SwwkMWIgg3nqRZp7WD+vQNNzIFPjoEf/ck/6jdBVtkQ=; b=XqUgaaXQpdC7CvOOK76vy+wBUTDxo8XlVCjT/kja3zkk1hgVyAvGvZ2sNnEaXfeRrC fYaZ+2lxnDINXSoAbSgEr0QxWjNKQXKXel39Kitd8EO4oLRovT4vjd24b5uJMZuI7gSD 7mZjtfmMPD3JHhsgldOa0fWJ0IPUg3fHwKhIugxGmJ5k54tXVdD4kuV08JczkeeSIxhb 93OnPQy2pe2F1Boq7EUQhZOqUodB7EGzSfmidHxIpxr7FLb+FEJt6YEeYf1jd15WyH8q RSlxglS60f2lmYkuuNGpOsWjw8DoDtTDKj7R0UbmSwbUSYwX4zL5PwDYtXYG6x4LUJtW bYpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SwwkMWIgg3nqRZp7WD+vQNNzIFPjoEf/ck/6jdBVtkQ=; b=VN2krHopxQtipXkosBu2cMsyaFwORMreOA7KtBhY6ywWILpTDitdvYCe6n+k7ArMnt U1rfQ3YcIX0q14Z1i2Qw15/KrlxMBKFt/px0brUPUkXK1PS75oT7us8BrBaA+ZZ3Ln6c TivzUtIo2Bj1ijgBl7fftqNazQI6povCz1XB/OzUIq545nMzI6mWrBDYMg3Th1xt9FOQ YqYTB6YJ23RU2ZAqTCZW0o/dlXm/laZoTI8D1ZG+b3RbbabM20WpYH1qfzExJkcxkfl3 hKAHUQshnqtEdRIxVLqH4Td7tJu3lZZhPfy9lgOB/99VdbLJRPi2f71TfuuHv8Bx/WXZ eL5A== X-Gm-Message-State: AOAM531aG1fMiRd0vK7AaLhm1uBZOUkdvuIWypBy3hHFn0NyMrVKWS0k njBVs4wXvQfeTHQC1JQT8UPOZVoW9KCs8GpSl7VF/8yV4Ho= X-Google-Smtp-Source: ABdhPJy49YYfxHmhtwSerH7HoVjS2jmcK7Bjtk6ZC39erq7ndMVRIC/q43vrZg0il5fq+6ZGune1C7hAPBizPFIwe34= X-Received: by 2002:a17:906:9be4:: with SMTP id de36mr5829145ejc.436.1630007088261; Thu, 26 Aug 2021 12:44:48 -0700 (PDT) MIME-Version: 1.0 References: <20210609210729.254578-1-Anna.Schumaker@Netapp.com> <20210614231440.GD16500@fieldses.org> <20210812203248.GA907@fieldses.org> In-Reply-To: <20210812203248.GA907@fieldses.org> From: Anna Schumaker Date: Thu, 26 Aug 2021 15:44:32 -0400 Message-ID: Subject: Re: [PATCH] sunrpc: Avoid a KASAN slab-out-of-bounds bug in xdr_set_page_base() To: "J. Bruce Fields" Cc: Trond Myklebust , Linux NFS Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Thu, Aug 12, 2021 at 4:32 PM J. Bruce Fields wrote: > > On Mon, Jun 14, 2021 at 07:14:40PM -0400, bfields wrote: > > On Wed, Jun 09, 2021 at 05:07:29PM -0400, schumaker.anna@gmail.com wrote: > > > From: Anna Schumaker > > > > > > This seems to happen fairly easily during READ_PLUS testing on NFS v4.2. > > > > Yep, I hit a KASAN warning here every time, and this fixes it, > > thanks.--b. > > By the way, config NFS_V4_2_READ_PLUS still says: > > This is intended for developers only. The READ_PLUS operation > has been shown to have issues under specific conditions and > should not be used in production. > > But this warning was the only thing I was seeing. Is there another > known issue remaining? I think it was an issue around using lseek to generate the reply. The file contents could change between each call, leading to inconsistent results (and a new failing xfstest that previously passed) Anna > > --b. > > > > > > I found that we could end up accessing xdr->buf->pages[pgnr] with a pgnr > > > greater than the number of pages in the array. So let's just return > > > early if we're setting base to a point at the end of the page data and > > > let xdr_set_tail_base() handle setting up the buffer pointers instead. > > > > > > Signed-off-by: Anna Schumaker > > > --- > > > net/sunrpc/xdr.c | 7 +++---- > > > 1 file changed, 3 insertions(+), 4 deletions(-) > > > > > > diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c > > > index 3964ff74ee51..ca10ba2626f2 100644 > > > --- a/net/sunrpc/xdr.c > > > +++ b/net/sunrpc/xdr.c > > > @@ -1230,10 +1230,9 @@ static unsigned int xdr_set_page_base(struct xdr_stream *xdr, > > > void *kaddr; > > > > > > maxlen = xdr->buf->page_len; > > > - if (base >= maxlen) { > > > - base = maxlen; > > > - maxlen = 0; > > > - } else > > > + if (base >= maxlen) > > > + return 0; > > > + else > > > maxlen -= base; > > > if (len > maxlen) > > > len = maxlen; > > > -- > > > 2.32.0