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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 5B3CEC432C3 for ; Sat, 16 Nov 2019 16:20:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2491C21479 for ; Sat, 16 Nov 2019 16:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573921235; bh=MY8vZzJfXFISQSXwE+EqUf4Dqx3adqhs2Rjdk7fKzSc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hP1y6cP57snmiJDwEQPl5Ag9T2oB1K9QfqTr+wduin7hT+oeERSh4CYK4B/oGPfkn w8m1W57+wRKlZDAaTCgCDdUeVSHhhXodFGQVVX1tqp9rw+4KIvrbAOUq8qmVS5SCN5 svOcDAqxkpkuff71od6DOY4ngpw74xTLMXmvrWm8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731763AbfKPQUe (ORCPT ); Sat, 16 Nov 2019 11:20:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:49392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728022AbfKPPoa (ORCPT ); Sat, 16 Nov 2019 10:44:30 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 255BA20833; Sat, 16 Nov 2019 15:44:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919069; bh=MY8vZzJfXFISQSXwE+EqUf4Dqx3adqhs2Rjdk7fKzSc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NjtAR7kejMkINgjjxZrU5xqhUox7rIGCUTn25PQQYCpQSq60nsLSIDMovxgC2eT6W 8L4YXr4/g2K9Jxd+MucEFpzYqLPAqojGYcHl5waDu2IQh8WhQGga1a0ECeCwFD6Q51 NktbZBi+u6A0MZZ3vVGymNIMtMfSnkgaDT5eTgy8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Darrick J. Wong" , Christoph Hellwig , Dave Chinner , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 141/237] vfs: avoid problematic remapping requests into partial EOF block Date: Sat, 16 Nov 2019 10:39:36 -0500 Message-Id: <20191116154113.7417-141-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154113.7417-1-sashal@kernel.org> References: <20191116154113.7417-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Darrick J. Wong" [ Upstream commit 07d19dc9fbe9128378b9e226abe886fd8fd473df ] A deduplication data corruption is exposed in XFS and btrfs. It is caused by extending the block match range to include the partial EOF block, but then allowing unknown data beyond EOF to be considered a "match" to data in the destination file because the comparison is only made to the end of the source file. This corrupts the destination file when the source extent is shared with it. The VFS remapping prep functions only support whole block dedupe, but we still need to appear to support whole file dedupe correctly. Hence if the dedupe request includes the last block of the souce file, don't include it in the actual dedupe operation. If the rest of the range dedupes successfully, then reject the entire request. A subsequent patch will enable us to shorten dedupe requests correctly. When reflinking sub-file ranges, a data corruption can occur when the source file range includes a partial EOF block. This shares the unknown data beyond EOF into the second file at a position inside EOF, exposing stale data in the second file. If the reflink request includes the last block of the souce file, only proceed with the reflink operation if it lands at or past the destination file's current EOF. If it lands within the destination file EOF, reject the entire request with -EINVAL and make the caller go the hard way. A subsequent patch will enable us to shorten reflink requests correctly. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Dave Chinner Signed-off-by: Sasha Levin --- fs/read_write.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index 5fb5ee5b8cd70..2195380620d02 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1715,6 +1715,34 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write) return security_file_permission(file, write ? MAY_WRITE : MAY_READ); } +/* + * Ensure that we don't remap a partial EOF block in the middle of something + * else. Assume that the offsets have already been checked for block + * alignment. + * + * For deduplication we always scale down to the previous block because we + * can't meaningfully compare post-EOF contents. + * + * For clone we only link a partial EOF block above the destination file's EOF. + */ +static int generic_remap_check_len(struct inode *inode_in, + struct inode *inode_out, + loff_t pos_out, + u64 *len, + bool is_dedupe) +{ + u64 blkmask = i_blocksize(inode_in) - 1; + + if ((*len & blkmask) == 0) + return 0; + + if (is_dedupe) + *len &= ~blkmask; + else if (pos_out + *len < i_size_read(inode_out)) + return -EINVAL; + + return 0; +} /* * Check that the two inodes are eligible for cloning, the ranges make @@ -1821,6 +1849,11 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in, return -EBADE; } + ret = generic_remap_check_len(inode_in, inode_out, pos_out, len, + is_dedupe); + if (ret) + return ret; + return 1; } EXPORT_SYMBOL(vfs_clone_file_prep_inodes); -- 2.20.1