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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 B5D34C0650E for ; Mon, 1 Jul 2019 15:34:38 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8D18020881; Mon, 1 Jul 2019 15:34:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="E91HI/rC"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="PfUaRumH"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="iD3SKZ4N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8D18020881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1hhyK5-0008LO-Ja; Mon, 01 Jul 2019 15:34:29 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1hhyJs-0008JJ-L3 for linux-f2fs-devel@lists.sourceforge.net; Mon, 01 Jul 2019 15:34:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=u61H/gwgjyULQ1rm03+rt15Bdb16dsB5g68vkpZtJ1o=; b=E91HI/rCf+RFZpGLq0OUocTqqV JfWMh+HB7Yq2I6SpA0gvshd9zPcmV+swadMAxjEvM9K5/8ajpC5CnxToPQS/gmjRiDL/guMM85iKG SpdbvwgUnK/wbwpanbhyqp9CdyzXobGKvcz3kkvxzBJJ/1LZ5uxiShhVsz01f2JagJBk=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=u61H/gwgjyULQ1rm03+rt15Bdb16dsB5g68vkpZtJ1o=; b=PfUaRumHasvvF5PkAqF2aslMNh fH/8a1cbw32DUDqUIIEMNDWBlIkyF29Db/lNTbWCIh6p5tnp+g50gP1YmdcgN16byS2j6II2OJR0u KGhMOxiabuG8Sx3Fu2sRB2hkwGXa0I722cwK1wNR+4ZXeB69cP284ebN4fX93a1smRs8=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) id 1hhyJz-000lNx-QD for linux-f2fs-devel@lists.sourceforge.net; Mon, 01 Jul 2019 15:34:25 +0000 Received: from sol.localdomain (c-24-5-143-220.hsd1.ca.comcast.net [24.5.143.220]) (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 6CBEF21851; Mon, 1 Jul 2019 15:34:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561995250; bh=A41vt4jGxIjxms6taEMGdqC+r7hlRcG0OlJSTNYg6+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iD3SKZ4NuFdVsvtTwHp67q1eLCgKv2yQih/QpjUim8OmpZnbzQ7oZYjMXY6u0gEAF k4Z4Btr2h50/1QSnvfvHDqxAUosnpP3S4X9u6kVl1RL7GZnMGJX6lq/nnHFBQ2r4Rl TN6KX7sDkc7P2+SgJ6zcV67wWlDIRxUtX3jf9tyo= From: Eric Biggers To: linux-fscrypt@vger.kernel.org Date: Mon, 1 Jul 2019 08:32:36 -0700 Message-Id: <20190701153237.1777-17-ebiggers@kernel.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190701153237.1777-1-ebiggers@kernel.org> References: <20190701153237.1777-1-ebiggers@kernel.org> MIME-Version: 1.0 X-Headers-End: 1hhyJz-000lNx-QD Subject: [f2fs-dev] [PATCH v6 16/17] ext4: update on-disk format documentation for fs-verity X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Theodore Y . Ts'o" , "Darrick J . Wong" , linux-api@vger.kernel.org, Dave Chinner , linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, Jaegeuk Kim , linux-integrity@vger.kernel.org, linux-ext4@vger.kernel.org, Linus Torvalds , Christoph Hellwig , Victor Hsieh Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net From: Eric Biggers Document the format of verity files on ext4, and the corresponding inode and superblock flags. Signed-off-by: Eric Biggers --- Documentation/filesystems/ext4/inodes.rst | 6 ++- Documentation/filesystems/ext4/overview.rst | 1 + Documentation/filesystems/ext4/super.rst | 2 + Documentation/filesystems/ext4/verity.rst | 41 +++++++++++++++++++++ 4 files changed, 48 insertions(+), 2 deletions(-) create mode 100644 Documentation/filesystems/ext4/verity.rst diff --git a/Documentation/filesystems/ext4/inodes.rst b/Documentation/filesystems/ext4/inodes.rst index 6bd35e506b6f..e851e6ca31fa 100644 --- a/Documentation/filesystems/ext4/inodes.rst +++ b/Documentation/filesystems/ext4/inodes.rst @@ -277,6 +277,8 @@ The ``i_flags`` field is a combination of these values: - This is a huge file (EXT4\_HUGE\_FILE\_FL). * - 0x80000 - Inode uses extents (EXT4\_EXTENTS\_FL). + * - 0x100000 + - Verity protected file (EXT4\_VERITY\_FL). * - 0x200000 - Inode stores a large extended attribute value in its data blocks (EXT4\_EA\_INODE\_FL). @@ -299,9 +301,9 @@ The ``i_flags`` field is a combination of these values: - Reserved for ext4 library (EXT4\_RESERVED\_FL). * - - Aggregate flags: - * - 0x4BDFFF + * - 0x705BDFFF - User-visible flags. - * - 0x4B80FF + * - 0x604BC0FF - User-modifiable flags. Note that while EXT4\_JOURNAL\_DATA\_FL and EXT4\_EXTENTS\_FL can be set with setattr, they are not in the kernel's EXT4\_FL\_USER\_MODIFIABLE mask, since it needs to handle the setting of diff --git a/Documentation/filesystems/ext4/overview.rst b/Documentation/filesystems/ext4/overview.rst index cbab18baba12..123ebfde47ee 100644 --- a/Documentation/filesystems/ext4/overview.rst +++ b/Documentation/filesystems/ext4/overview.rst @@ -24,3 +24,4 @@ order. .. include:: bigalloc.rst .. include:: inlinedata.rst .. include:: eainode.rst +.. include:: verity.rst diff --git a/Documentation/filesystems/ext4/super.rst b/Documentation/filesystems/ext4/super.rst index 04ff079a2acf..6eae92054827 100644 --- a/Documentation/filesystems/ext4/super.rst +++ b/Documentation/filesystems/ext4/super.rst @@ -696,6 +696,8 @@ the following: (RO\_COMPAT\_READONLY) * - 0x2000 - Filesystem tracks project quotas. (RO\_COMPAT\_PROJECT) + * - 0x8000 + - Verity inodes may be present on the filesystem. (RO\_COMPAT\_VERITY) .. _super_def_hash: diff --git a/Documentation/filesystems/ext4/verity.rst b/Documentation/filesystems/ext4/verity.rst new file mode 100644 index 000000000000..3e4c0ee0e068 --- /dev/null +++ b/Documentation/filesystems/ext4/verity.rst @@ -0,0 +1,41 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Verity files +------------ + +ext4 supports fs-verity, which is a filesystem feature that provides +Merkle tree based hashing for individual readonly files. Most of +fs-verity is common to all filesystems that support it; see +:ref:`Documentation/filesystems/fsverity.rst ` for the +fs-verity documentation. However, the on-disk layout of the verity +metadata is filesystem-specific. On ext4, the verity metadata is +stored after the end of the file data itself, in the following format: + +- Zero-padding to the next 65536-byte boundary. This padding need not + actually be allocated on-disk, i.e. it may be a hole. + +- The Merkle tree, as documented in + :ref:`Documentation/filesystems/fsverity.rst + `, with the tree levels stored in order from + root to leaf, and the tree blocks within each level stored in their + natural order. + +- Zero-padding to the next filesystem block boundary. + +- The verity descriptor, as documented in + :ref:`Documentation/filesystems/fsverity.rst `, + with optionally appended signature blob. + +- Zero-padding to the next offset that is 4 bytes before a filesystem + block boundary. + +- The size of the verity descriptor in bytes, as a 4-byte little + endian integer. + +Verity inodes have EXT4_VERITY_FL set, and they must use extents, i.e. +EXT4_EXTENTS_FL must be set and EXT4_INLINE_DATA_FL must be clear. +They can have EXT4_ENCRYPT_FL set, in which case the verity metadata +is encrypted as well as the data itself. + +Verity files cannot have blocks allocated past the end of the verity +metadata. -- 2.22.0 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel