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| author | Eric Biggers <ebiggers@google.com> | 2019-07-22 09:26:24 -0700 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2019-08-12 19:33:50 -0700 |
| commit | c93d8f88580921c84d2213161ef3c22560511b84 (patch) | |
| tree | a113a5c4cbb04d656ebf22f10193745602d923c3 /fs/ext4/Makefile | |
| parent | 432434c9f8e18cb4cf0fe05bc3eeceada0e10dc6 (diff) | |
| download | linux-stable-c93d8f88580921c84d2213161ef3c22560511b84.tar.gz linux-stable-c93d8f88580921c84d2213161ef3c22560511b84.tar.bz2 linux-stable-c93d8f88580921c84d2213161ef3c22560511b84.zip | |
ext4: add basic fs-verity support
Add most of fs-verity support to ext4. fs-verity is a filesystem
feature that enables transparent integrity protection and authentication
of read-only files. It uses a dm-verity like mechanism at the file
level: a Merkle tree is used to verify any block in the file in
log(filesize) time. It is implemented mainly by helper functions in
fs/verity/. See Documentation/filesystems/fsverity.rst for the full
documentation.
This commit adds all of ext4 fs-verity support except for the actual
data verification, including:
- Adding a filesystem feature flag and an inode flag for fs-verity.
- Implementing the fsverity_operations to support enabling verity on an
inode and reading/writing the verity metadata.
- Updating ->write_begin(), ->write_end(), and ->writepages() to support
writing verity metadata pages.
- Calling the fs-verity hooks for ->open(), ->setattr(), and ->ioctl().
ext4 stores the verity metadata (Merkle tree and fsverity_descriptor)
past the end of the file, starting at the first 64K boundary beyond
i_size. This approach works because (a) verity files are readonly, and
(b) pages fully beyond i_size aren't visible to userspace but can be
read/written internally by ext4 with only some relatively small changes
to ext4. This approach avoids having to depend on the EA_INODE feature
and on rearchitecturing ext4's xattr support to support paging
multi-gigabyte xattrs into memory, and to support encrypting xattrs.
Note that the verity metadata *must* be encrypted when the file is,
since it contains hashes of the plaintext data.
This patch incorporates work by Theodore Ts'o and Chandan Rajendra.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/ext4/Makefile')
| -rw-r--r-- | fs/ext4/Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile index 8fdfcd3c3e04..b17ddc229ac5 100644 --- a/fs/ext4/Makefile +++ b/fs/ext4/Makefile @@ -13,3 +13,4 @@ ext4-y := balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \ ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o +ext4-$(CONFIG_FS_VERITY) += verity.o |