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| author | Eric Biggers <ebiggers@google.com> | 2021-01-15 21:18:17 +0300 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2021-02-08 01:51:14 +0300 |
| commit | 622699cfe6ec5578f52727002d5717ff3f092e23 (patch) | |
| tree | 70afcd4d36b8ca0d535043f3e64ec23000bc6bff /Documentation/filesystems | |
| parent | e17fe6579de023725ec22a16965e9099e4a05ac9 (diff) | |
| download | linux-622699cfe6ec5578f52727002d5717ff3f092e23.tar.xz | |
fs-verity: support reading Merkle tree with ioctl
Add support for FS_VERITY_METADATA_TYPE_MERKLE_TREE to
FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to
retrieve the Merkle tree of a verity file for serving to a client which
implements fs-verity compatible verification. See the patch which
introduced FS_IOC_READ_VERITY_METADATA for more details.
This has been tested using a new xfstest which calls this ioctl via a
new subcommand for the 'fsverity' program from fsverity-utils.
Link: https://lore.kernel.org/r/20210115181819.34732-5-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/fsverity.rst | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 9ef7a7de6008..50b47a6d9ea1 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -234,6 +234,8 @@ need this ioctl. This ioctl takes in a pointer to the following structure:: + #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 + struct fsverity_read_metadata_arg { __u64 metadata_type; __u64 offset; @@ -242,7 +244,13 @@ This ioctl takes in a pointer to the following structure:: __u64 __reserved; }; -``metadata_type`` specifies the type of metadata to read. +``metadata_type`` specifies the type of metadata to read: + +- ``FS_VERITY_METADATA_TYPE_MERKLE_TREE`` reads the blocks of the + Merkle tree. The blocks are returned in order from the root level + to the leaf level. Within each level, the blocks are returned in + the same order that their hashes are themselves hashed. + See `Merkle tree`_ for more information. The semantics are similar to those of ``pread()``. ``offset`` specifies the offset in bytes into the metadata item to read from, and |