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From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org, ebiggers@kernel.org, aalbersh@redhat.com
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	fsverity@lists.linux.dev
Subject: [PATCH 10/13] fsverity: pass the zero-hash value to the implementation
Date: Fri, 29 Mar 2024 17:35:17 -0700	[thread overview]
Message-ID: <171175868031.1987804.13138670908694064691.stgit@frogsfrogsfrogs> (raw)
In-Reply-To: <171175867829.1987804.15934006844321506283.stgit@frogsfrogsfrogs>

From: Darrick J. Wong <djwong@kernel.org>

Compute the hash of a data block full of zeros, and then supply this to
the merkle tree read and write methods.  A subsequent xfs patch will use
this to reduce the size of the merkle tree when dealing with sparse gold
master disk images and the like.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/verity/enable.c           |    2 ++
 fs/verity/fsverity_private.h |    2 ++
 fs/verity/open.c             |    7 +++++++
 fs/verity/verify.c           |    2 ++
 include/linux/fsverity.h     |    8 ++++++++
 5 files changed, 21 insertions(+)


diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index 233b20fb12ff5..8c6fe4b72b14e 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -52,6 +52,8 @@ static int write_merkle_tree_block(struct inode *inode, const u8 *buf,
 {
 	struct fsverity_writemerkle req = {
 		.inode = inode,
+		.zero_digest = params->zero_digest,
+		.digest_size = params->digest_size,
 	};
 	u64 pos = (u64)index << params->log_blocksize;
 	int err;
diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index de8798f141d4a..195a92f203bba 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -47,6 +47,8 @@ struct merkle_tree_params {
 	u64 tree_size;			/* Merkle tree size in bytes */
 	unsigned long tree_pages;	/* Merkle tree size in pages */
 
+	u8 zero_digest[FS_VERITY_MAX_DIGEST_SIZE]; /* hash of zeroed data block */
+
 	/*
 	 * Starting block index for each tree level, ordered from leaf level (0)
 	 * to root level ('num_levels - 1')
diff --git a/fs/verity/open.c b/fs/verity/open.c
index 7a86407732c41..cdf694a261605 100644
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -144,6 +144,13 @@ int fsverity_init_merkle_tree_params(struct merkle_tree_params *params,
 		goto out_err;
 	}
 
+	err = fsverity_hash_block(params, inode, page_address(ZERO_PAGE(0)),
+				   params->zero_digest);
+	if (err) {
+		fsverity_err(inode, "Error %d computing zero digest", err);
+		goto out_err;
+	}
+
 	params->tree_size = offset << log_blocksize;
 	params->tree_pages = PAGE_ALIGN(params->tree_size) >> PAGE_SHIFT;
 	return 0;
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index c4ebf85ba2c79..99b1529bbb50b 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -432,6 +432,8 @@ int fsverity_read_merkle_tree_block(struct inode *inode,
 			.num_levels = params->num_levels,
 			.log_blocksize = params->log_blocksize,
 			.ra_bytes = ra_bytes,
+			.zero_digest = params->zero_digest,
+			.digest_size = params->digest_size,
 		};
 
 		block->verified = false;
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index 5dacd30d65353..761a0b76eefec 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -66,6 +66,8 @@ struct fsverity_blockbuf {
  *		if the page at @block->offset isn't already cached.
  *		Implementations may ignore this argument; it's only a
  *		performance optimization.
+ * @zero_digest: the hash for a data block of zeroes
+ * @digest_size: size of zero_digest
  */
 struct fsverity_readmerkle {
 	struct inode *inode;
@@ -73,6 +75,8 @@ struct fsverity_readmerkle {
 	int level;
 	int num_levels;
 	u8 log_blocksize;
+	const u8 *zero_digest;
+	unsigned int digest_size;
 };
 
 /**
@@ -81,12 +85,16 @@ struct fsverity_readmerkle {
  * @level: level of the block; level 0 are the leaves
  * @num_levels: number of levels in the tree total
  * @log_blocksize: log2 of the size of the block
+ * @zero_digest: the hash for a data block of zeroes
+ * @digest_size: size of zero_digest
  */
 struct fsverity_writemerkle {
 	struct inode *inode;
 	int level;
 	int num_levels;
 	u8 log_blocksize;
+	const u8 *zero_digest;
+	unsigned int digest_size;
 };
 
 /* Verity operations for filesystems */


  parent reply	other threads:[~2024-03-30  0:35 UTC|newest]

Thread overview: 111+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-30  0:30 [PATCHBOMB v5.5] fs-verity support for XFS Darrick J. Wong
2024-03-30  0:32 ` [PATCHSET v5.5 1/2] fs-verity: support merkle tree access by blocks Darrick J. Wong
2024-03-30  0:32   ` [PATCH 01/13] fs: add FS_XFLAG_VERITY for verity files Darrick J. Wong
2024-03-30  0:33   ` [PATCH 02/13] fsverity: pass tree_blocksize to end_enable_verity() Darrick J. Wong
2024-03-30  0:33   ` [PATCH 03/13] fsverity: support block-based Merkle tree caching Darrick J. Wong
2024-04-05  2:31     ` Eric Biggers
2024-04-24 21:25       ` Darrick J. Wong
2024-04-24 22:08         ` Eric Biggers
2024-04-25  0:27           ` Darrick J. Wong
2024-04-25  0:46             ` Eric Biggers
2024-04-25  0:53               ` Darrick J. Wong
2024-03-30  0:33   ` [PATCH 04/13] fsverity: add per-sb workqueue for post read processing Darrick J. Wong
2024-04-05  2:39     ` Eric Biggers
2024-04-24 21:33       ` Darrick J. Wong
2024-03-30  0:33   ` [PATCH 05/13] fsverity: add tracepoints Darrick J. Wong
2024-03-30  0:34   ` [PATCH 06/13] fsverity: send the level of the merkle tree block to ->read_merkle_tree_block Darrick J. Wong
2024-04-05  2:42     ` Eric Biggers
2024-04-25  0:30       ` Darrick J. Wong
2024-03-30  0:34   ` [PATCH 07/13] fsverity: pass the new tree size and block size to ->begin_enable_verity Darrick J. Wong
2024-04-05  2:46     ` Eric Biggers
2024-04-24 21:36       ` Darrick J. Wong
2024-03-30  0:34   ` [PATCH 08/13] fsverity: expose merkle tree geometry to callers Darrick J. Wong
2024-04-05  2:50     ` Eric Biggers
2024-04-25  0:45       ` Darrick J. Wong
2024-04-25  0:49         ` Eric Biggers
2024-04-25  1:01           ` Darrick J. Wong
2024-04-25  1:04             ` Eric Biggers
2024-03-30  0:35   ` [PATCH 09/13] fsverity: box up the write_merkle_tree_block parameters too Darrick J. Wong
2024-04-05  2:52     ` Eric Biggers
2024-04-25  0:46       ` Darrick J. Wong
2024-03-30  0:35   ` Darrick J. Wong [this message]
2024-04-05  2:57     ` [PATCH 10/13] fsverity: pass the zero-hash value to the implementation Eric Biggers
2024-04-24 19:02       ` Darrick J. Wong
2024-04-24 19:19         ` Eric Biggers
2024-04-24 20:23           ` Darrick J. Wong
2024-04-24 20:59             ` Eric Biggers
2024-04-24 21:43               ` Darrick J. Wong
2024-03-30  0:35   ` [PATCH 11/13] fsverity: report validation errors back to the filesystem Darrick J. Wong
2024-04-05  3:09     ` Eric Biggers
2024-04-24 18:18       ` Darrick J. Wong
2024-04-24 18:52         ` Eric Biggers
2024-04-24 19:03           ` Darrick J. Wong
2024-03-30  0:35   ` [PATCH 12/13] fsverity: remove system-wide workqueue Darrick J. Wong
2024-04-05  3:14     ` Eric Biggers
2024-04-24 18:05       ` Darrick J. Wong
2024-04-24 18:41         ` Eric Biggers
2024-04-29 10:15         ` Andrey Albershteyn
2024-04-29 16:35           ` Darrick J. Wong
2024-03-30  0:36   ` [PATCH 13/13] iomap: integrate fs-verity verification into iomap's read path Darrick J. Wong
2024-03-30  0:32 ` [PATCHSET v5.5 2/2] xfs: fs-verity support Darrick J. Wong
2024-03-30  0:36   ` [PATCH 01/29] xfs: use unsigned ints for non-negative quantities in xfs_attr_remote.c Darrick J. Wong
2024-04-02  9:51     ` Andrey Albershteyn
2024-04-02 16:25       ` Darrick J. Wong
2024-03-30  0:36   ` [PATCH 02/29] xfs: turn XFS_ATTR3_RMT_BUF_SPACE into a function Darrick J. Wong
2024-04-02 10:09     ` Andrey Albershteyn
2024-03-30  0:36   ` [PATCH 03/29] xfs: create a helper to compute the blockcount of a max sized remote value Darrick J. Wong
2024-04-02 10:09     ` Andrey Albershteyn
2024-03-30  0:37   ` [PATCH 04/29] xfs: minor cleanups of xfs_attr3_rmt_blocks Darrick J. Wong
2024-04-02 10:11     ` Andrey Albershteyn
2024-03-30  0:37   ` [PATCH 05/29] xfs: add attribute type for fs-verity Darrick J. Wong
2024-03-30  0:37   ` [PATCH 06/29] xfs: do not use xfs_attr3_rmt_hdr for remote verity value blocks Darrick J. Wong
2024-03-30  0:37   ` [PATCH 07/29] xfs: add fs-verity ro-compat flag Darrick J. Wong
2024-03-30  0:38   ` [PATCH 08/29] xfs: add inode on-disk VERITY flag Darrick J. Wong
2024-03-30  0:38   ` [PATCH 09/29] xfs: initialize fs-verity on file open and cleanup on inode destruction Darrick J. Wong
2024-03-30  0:38   ` [PATCH 10/29] xfs: don't allow to enable DAX on fs-verity sealed inode Darrick J. Wong
2024-03-30  0:38   ` [PATCH 11/29] xfs: disable direct read path for fs-verity files Darrick J. Wong
2024-03-30  0:39   ` [PATCH 12/29] xfs: widen flags argument to the xfs_iflags_* helpers Darrick J. Wong
2024-04-02 12:37     ` Andrey Albershteyn
2024-04-02 16:27       ` Darrick J. Wong
2024-03-30  0:39   ` [PATCH 13/29] xfs: add fs-verity support Darrick J. Wong
2024-04-02  8:42     ` Andrey Albershteyn
2024-04-02 16:34       ` Darrick J. Wong
2024-04-25  1:14         ` Darrick J. Wong
2024-03-30  0:39   ` [PATCH 14/29] xfs: create a per-mount shrinker for verity inodes merkle tree blocks Darrick J. Wong
2024-04-05  3:16     ` Eric Biggers
2024-04-24 17:39       ` Darrick J. Wong
2024-03-30  0:39   ` [PATCH 15/29] xfs: create an icache tag for files with cached " Darrick J. Wong
2024-03-30  0:40   ` [PATCH 16/29] xfs: shrink verity blob cache Darrick J. Wong
2024-03-30  0:40   ` [PATCH 17/29] xfs: only allow the verity iflag for regular files Darrick J. Wong
2024-04-02 12:52     ` Andrey Albershteyn
2024-03-30  0:40   ` [PATCH 18/29] xfs: don't store trailing zeroes of merkle tree blocks Darrick J. Wong
2024-03-30  0:41   ` [PATCH 19/29] xfs: use merkle tree offset as attr hash Darrick J. Wong
2024-03-30  0:41   ` [PATCH 20/29] xfs: don't bother storing merkle tree blocks for zeroed data blocks Darrick J. Wong
2024-03-30  0:41   ` [PATCH 21/29] xfs: add fs-verity ioctls Darrick J. Wong
2024-03-30  0:41   ` [PATCH 22/29] xfs: advertise fs-verity being available on filesystem Darrick J. Wong
2024-04-02 13:44     ` Andrey Albershteyn
2024-03-30  0:42   ` [PATCH 23/29] xfs: make scrub aware of verity dinode flag Darrick J. Wong
2024-03-30  0:42   ` [PATCH 24/29] xfs: teach online repair to evaluate fsverity xattrs Darrick J. Wong
2024-04-02 15:42     ` Andrey Albershteyn
2024-04-02 16:42       ` Darrick J. Wong
2024-03-30  0:42   ` [PATCH 25/29] xfs: report verity failures through the health system Darrick J. Wong
2024-04-02 16:16     ` Andrey Albershteyn
2024-03-30  0:42   ` [PATCH 26/29] xfs: clear the verity iflag when not appropriate Darrick J. Wong
2024-04-02 16:26     ` Andrey Albershteyn
2024-03-30  0:43   ` [PATCH 27/29] xfs: make it possible to disable fsverity Darrick J. Wong
2024-04-02 17:15     ` Andrey Albershteyn
2024-04-02 23:25     ` Eric Biggers
2024-04-03  1:26       ` Darrick J. Wong
2024-03-30  0:43   ` [PATCH 28/29] xfs: allow verity files to be opened even if the fsverity metadata is damaged Darrick J. Wong
2024-04-02 18:04     ` Andrey Albershteyn
2024-04-02 20:00     ` Colin Walters
2024-04-02 22:52       ` Darrick J. Wong
2024-04-02 23:45         ` Eric Biggers
2024-04-03  1:34           ` Darrick J. Wong
2024-04-03  0:10         ` Colin Walters
2024-04-03  1:39           ` Darrick J. Wong
2024-04-03  1:59             ` Dave Chinner
2024-04-03  3:19               ` Darrick J. Wong
2024-04-03 22:22                 ` Dave Chinner
2024-04-03  8:35           ` Alexander Larsson
2024-03-30  0:43   ` [PATCH 29/29] xfs: enable ro-compat fs-verity flag Darrick J. Wong

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