From patchwork Wed Nov 18 19:18:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Omar Sandoval X-Patchwork-Id: 11915633 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 E0545C63798 for ; Wed, 18 Nov 2020 19:18:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F7A42220B for ; Wed, 18 Nov 2020 19:18:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=osandov-com.20150623.gappssmtp.com header.i=@osandov-com.20150623.gappssmtp.com header.b="MEITxHKB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727053AbgKRTSo (ORCPT ); Wed, 18 Nov 2020 14:18:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727006AbgKRTSn (ORCPT ); Wed, 18 Nov 2020 14:18:43 -0500 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 839F9C0613D4 for ; Wed, 18 Nov 2020 11:18:42 -0800 (PST) Received: by mail-pg1-x544.google.com with SMTP id r18so1861886pgu.6 for ; Wed, 18 Nov 2020 11:18:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osandov-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=m7uYqXPNxmB3NJk85TLjUTUGKHsEBU0JHVgTNlvuKfk=; b=MEITxHKBEVp5VQOUtUnxBIxrhvNItdX+33pUOiZv7z+jsw0CJ0zx30t92E7hiP05Cy Rg4W/lFeFgZengS8oq3sVWns2X6IYBgxP5o7aKoKqrp6zGFxKiW3To02WsasxS79RsfX 0vqLnbZ2hE004FFjJSvjJTQEHFV/JIh4wkrGdUUTztYX6sSxX/XydQFu3xXKNQz+KOko H8lDqC775NEg4YWx20VLawXI/Kag65sC/Z7eE+kNd1Jj+QclJJzq5kzUX1EDlwubsGze qHZUzRuaCQHuhYRz3RF1dsn1IztM6xOrIG9OWjbSNvYjKiNK/+g7ke/B36lxZ0pnBIaj fFcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=m7uYqXPNxmB3NJk85TLjUTUGKHsEBU0JHVgTNlvuKfk=; b=LPzTnBUYf7Pb1yZ8/0sEDI3fOyReYHleuc59CO5LF3iRMYmIqHZgVRfhXX6PimQh8t nh0cCriVEdIO6g72AuTkXhbJ/dIg8RnZodoOoiU6OBAiLfEoShYcaA8iO1nof5cBl6N1 QkLd/a49ju1/rSNcNdtNho/wpE0/nJLMmcGEMq2BQ3DZUlCm815lbuShnfhZqprS2iJL rAJjpj2oE+H/LPrDMyNjseGEveYe/2mGLXb+LV2BhKenOqjdpReMd61kfGgZI8V0R99P LSjUD7pR85fmrjiiSNRKk8gGmKBEm1mbMhyd7SkalRn0MOU66g36KOlSuOy+AAbLyof+ VHhA== X-Gm-Message-State: AOAM5327kwZg0TkX4nNgb53KUN7Yg+LHspgrZvbXgTPyAQ6xNE0fDRN7 TgqeafbqLzO5Et8hmFBWUtEgS2pxMkhd3w== X-Google-Smtp-Source: ABdhPJxRmGhnAdEblWauTa3klfdsSMqiSeTacprWs3MefG3RQwxUWrLRO1LNmuoC8/sMagh0dN8LgA== X-Received: by 2002:a17:90a:a891:: with SMTP id h17mr505257pjq.149.1605727121477; Wed, 18 Nov 2020 11:18:41 -0800 (PST) Received: from relinquished.tfbnw.net ([2620:10d:c090:400::5:8b43]) by smtp.gmail.com with ESMTPSA id c22sm19491863pfo.211.2020.11.18.11.18.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Nov 2020 11:18:40 -0800 (PST) From: Omar Sandoval To: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, Al Viro , Christoph Hellwig Cc: Dave Chinner , Jann Horn , Amir Goldstein , Aleksa Sarai , linux-api@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v6 04/11] btrfs: fix btrfs_write_check() Date: Wed, 18 Nov 2020 11:18:11 -0800 Message-Id: X-Mailer: git-send-email 2.29.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Omar Sandoval btrfs_write_check() has two related bugs: 1. It gets the iov_iter count before calling generic_write_checks(), but generic_write_checks() may truncate the iov_iter. 2. It returns the count or negative errno as a size_t, which the callers cast to an int. If the count is greater than INT_MAX, this overflows. To fix both of these, pull the call to generic_write_checks() out of btrfs_write_check(), use the new iov_iter count returned from generic_write_checks(), and have btrfs_write_check() return 0 or a negative errno as an int instead of the count. This rearrangement also paves the way for RWF_ENCODED write support. Fixes: f945968ff64c ("btrfs: introduce btrfs_write_check()") Signed-off-by: Omar Sandoval --- fs/btrfs/file.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index d217b739b164..7225b63b62a9 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1583,21 +1583,17 @@ static void update_time_for_write(struct inode *inode) inode_inc_iversion(inode); } -static size_t btrfs_write_check(struct kiocb *iocb, struct iov_iter *from) +static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from, + size_t count) { struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); loff_t pos = iocb->ki_pos; - size_t count = iov_iter_count(from); int err; loff_t oldsize; loff_t start_pos; - err = generic_write_checks(iocb, from); - if (err <= 0) - return err; - if (iocb->ki_flags & IOCB_NOWAIT) { size_t nocow_bytes = count; @@ -1639,7 +1635,7 @@ static size_t btrfs_write_check(struct kiocb *iocb, struct iov_iter *from) } } - return count; + return 0; } static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, @@ -1656,7 +1652,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, u64 lockend; size_t num_written = 0; int nrptrs; - int ret = 0; + ssize_t ret; bool only_release_metadata = false; bool force_page_uptodate = false; loff_t old_isize = i_size_read(inode); @@ -1669,10 +1665,14 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, if (ret < 0) return ret; - ret = btrfs_write_check(iocb, i); + ret = generic_write_checks(iocb, i); if (ret <= 0) goto out; + ret = btrfs_write_check(iocb, i, ret); + if (ret < 0) + goto out; + pos = iocb->ki_pos; nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE), PAGE_SIZE / (sizeof(struct page *))); @@ -1904,7 +1904,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) ssize_t written = 0; ssize_t written_buffered; loff_t endbyte; - int err; + ssize_t err; unsigned int ilock_flags = 0; struct iomap_dio *dio = NULL; @@ -1920,8 +1920,14 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) if (err < 0) return err; - err = btrfs_write_check(iocb, from); + err = generic_write_checks(iocb, from); if (err <= 0) { + btrfs_inode_unlock(inode, ilock_flags); + return err; + } + + err = btrfs_write_check(iocb, from, err); + if (err < 0) { btrfs_inode_unlock(inode, ilock_flags); goto out; }