linux/fs/verity
Eric Biggers 672d6ef4c7 fsverity: improve documentation for builtin signature support
fsverity builtin signatures (CONFIG_FS_VERITY_BUILTIN_SIGNATURES) aren't
the only way to do signatures with fsverity, and they have some major
limitations.  Yet, more users have tried to use them, e.g. recently by
https://github.com/ostreedev/ostree/pull/2640.  In most cases this seems
to be because users aren't sufficiently familiar with the limitations of
this feature and what the alternatives are.

Therefore, make some updates to the documentation to try to clarify the
properties of this feature and nudge users in the right direction.

Note that the Integrity Policy Enforcement (IPE) LSM, which is not yet
upstream, is planned to use the builtin signatures.  (This differs from
IMA, which uses its own signature mechanism.)  For that reason, my
earlier patch "fsverity: mark builtin signatures as deprecated"
(https://lore.kernel.org/r/20221208033548.122704-1-ebiggers@kernel.org),
which marked builtin signatures as "deprecated", was controversial.

This patch therefore stops short of marking the feature as deprecated.
I've also revised the language to focus on better explaining the feature
and what its alternatives are.

Link: https://lore.kernel.org/r/20230620041937.5809-1-ebiggers@kernel.org
Reviewed-by: Colin Walters <walters@verbum.org>
Reviewed-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-06-20 22:47:55 -07:00
..
enable.c fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
fsverity_private.h fsverity: constify fsverity_hash_alg 2023-06-04 05:56:11 -07:00
hash_algs.c fsverity: constify fsverity_hash_alg 2023-06-04 05:56:11 -07:00
init.c fsverity: remove debug messages and CONFIG_FS_VERITY_DEBUG 2023-01-01 15:46:48 -08:00
Kconfig fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
Makefile fs-verity: add FS_IOC_READ_VERITY_METADATA ioctl 2021-02-07 14:51:11 -08:00
measure.c fsverity: rework fsverity_get_digest() again 2023-06-14 10:41:07 -07:00
open.c fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
read_metadata.c fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
signature.c fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
verify.c fsverity: simplify error handling in verify_data_block() 2023-06-04 05:56:11 -07:00