mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
synced 2025-01-18 06:15:12 +00:00
671e67b47e
Add the beginnings of the fs/verity/ support layer, including the Kconfig option and various helper functions for hashing. To start, only SHA-256 is supported, but other hash algorithms can easily be added. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
39 lines
1.5 KiB
Plaintext
39 lines
1.5 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
|
|
|
|
config FS_VERITY
|
|
bool "FS Verity (read-only file-based authenticity protection)"
|
|
select CRYPTO
|
|
# SHA-256 is selected as it's intended to be the default hash algorithm.
|
|
# To avoid bloat, other wanted algorithms must be selected explicitly.
|
|
select CRYPTO_SHA256
|
|
help
|
|
This option enables fs-verity. fs-verity is the dm-verity
|
|
mechanism implemented at the file level. On supported
|
|
filesystems (currently EXT4 and F2FS), userspace can use an
|
|
ioctl to enable verity for a file, which causes the filesystem
|
|
to build a Merkle tree for the file. The filesystem will then
|
|
transparently verify any data read from the file against the
|
|
Merkle tree. The file is also made read-only.
|
|
|
|
This serves as an integrity check, but the availability of the
|
|
Merkle tree root hash also allows efficiently supporting
|
|
various use cases where normally the whole file would need to
|
|
be hashed at once, such as: (a) auditing (logging the file's
|
|
hash), or (b) authenticity verification (comparing the hash
|
|
against a known good value, e.g. from a digital signature).
|
|
|
|
fs-verity is especially useful on large files where not all
|
|
the contents may actually be needed. Also, fs-verity verifies
|
|
data each time it is paged back in, which provides better
|
|
protection against malicious disks vs. an ahead-of-time hash.
|
|
|
|
If unsure, say N.
|
|
|
|
config FS_VERITY_DEBUG
|
|
bool "FS Verity debugging"
|
|
depends on FS_VERITY
|
|
help
|
|
Enable debugging messages related to fs-verity by default.
|
|
|
|
Say N unless you are an fs-verity developer.
|