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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99CD3C433EF for ; Mon, 18 Apr 2022 12:27:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234709AbiDRM3p (ORCPT ); Mon, 18 Apr 2022 08:29:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239689AbiDRM2l (ORCPT ); Mon, 18 Apr 2022 08:28:41 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EED7201A6; Mon, 18 Apr 2022 05:22:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C65EEB80EDE; Mon, 18 Apr 2022 12:22:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F948C385A7; Mon, 18 Apr 2022 12:22:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650284539; bh=qQSYxwQ0a1zzq3hdUWO+WEoi8GCOsoUpjcM8TqNU80Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LL7XocXYd4vG563boaAwKIV2w7qnbwd+4pfPxisMcpA4BgzT+qPycpzhB/ZSFqRMY doSavBsDWO4kfcO1A1101DwncCw0AHlTeGbEE+rwUeCQwxQ3UhPFhed98ZfG8Bcm9N nttEN6c2WYqd/0lt7udYxEUEK8jkfLbWjx3EkQBU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , "Darrick J. Wong" , David Sterba , Sasha Levin Subject: [PATCH 5.17 131/219] btrfs: fix fallocate to use file_modified to update permissions consistently Date: Mon, 18 Apr 2022 14:11:40 +0200 Message-Id: <20220418121210.562765021@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121203.462784814@linuxfoundation.org> References: <20220418121203.462784814@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Darrick J. Wong [ Upstream commit 05fd9564e9faf0f23b4676385e27d9405cef6637 ] Since the initial introduction of (posix) fallocate back at the turn of the century, it has been possible to use this syscall to change the user-visible contents of files. This can happen by extending the file size during a preallocation, or through any of the newer modes (punch, zero range). Because the call can be used to change file contents, we should treat it like we do any other modification to a file -- update the mtime, and drop set[ug]id privileges/capabilities. The VFS function file_modified() does all this for us if pass it a locked inode, so let's make fallocate drop permissions correctly. Reviewed-by: Filipe Manana Signed-off-by: Darrick J. Wong Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/file.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index a0179cc62913..28ddd9cf2069 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2918,8 +2918,9 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, return ret; } -static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) +static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len) { + struct inode *inode = file_inode(file); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_root *root = BTRFS_I(inode)->root; struct extent_state *cached_state = NULL; @@ -2951,6 +2952,10 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) goto out_only_mutex; } + ret = file_modified(file); + if (ret) + goto out_only_mutex; + lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode))); lockend = round_down(offset + len, btrfs_inode_sectorsize(BTRFS_I(inode))) - 1; @@ -3391,7 +3396,7 @@ static long btrfs_fallocate(struct file *file, int mode, return -EOPNOTSUPP; if (mode & FALLOC_FL_PUNCH_HOLE) - return btrfs_punch_hole(inode, offset, len); + return btrfs_punch_hole(file, offset, len); /* * Only trigger disk allocation, don't trigger qgroup reserve @@ -3413,6 +3418,10 @@ static long btrfs_fallocate(struct file *file, int mode, goto out; } + ret = file_modified(file); + if (ret) + goto out; + /* * TODO: Move these two operations after we have checked * accurate reserved space, or fallocate can still fail but -- 2.35.1