From: Alexander Larsson <alexl@redhat.com>
To: miklos@szeredi.hu
Cc: linux-unionfs@vger.kernel.org, amir73il@gmail.com,
ebiggers@kernel.org, tytso@mit.edu, fsverity@lists.linux.dev,
Alexander Larsson <alexl@redhat.com>
Subject: [PATCH v4 0/3] ovl: Add support for fs-verity checking of lowerdata
Date: Tue, 20 Jun 2023 12:15:15 +0200 [thread overview]
Message-ID: <cover.1687255035.git.alexl@redhat.com> (raw)
This patchset adds support for using fs-verity to validate lowerdata
files by specifying an overlay.verity xattr on the metacopy
files.
This is primarily motivated by the Composefs usecase, where there will
be a read-only EROFS layer that contains redirect into a base data
layer which has fs-verity enabled on all files. However, it is also
useful in general if you want to ensure that the lowerdata files
matches the expected content over time.
I have also added some tests for this feature to xfstests[1].
This series depends on the commit
fsverity: rework fsverity_get_digest() again
Which is in the "for-next" branch of
https://git.kernel.org/pub/scm/fs/fsverity/linux.git/
This series, plus the above commit are also in git here:
https://github.com/alexlarsson/linux/tree/overlay-verity
I would love to see this go into 6.5. So Eric, could you maybe Ack the
implementation patches separately from the documentation patches? Then
maybe we can get this in early, and I promise to try to get the
documentation up to standard during the 6.5 cycle as needed.
Changes since v3:
* Instead of using a overlay.digest xattr we extend the current
overlay.metacopy xattr with version, flags and digest. This makes
it flexible for later changes and allows us to use the existing
xattr lookup to know ahead of time whether a file needs to have
verity validated.
I've done some performance checks on this new layout, and the
results are essentially the same as before.
* This is rebased on top of the latest overlayfs-next, which includes
the changes to the new mount API, so that part has been redone.
* The documentation changes have been rewritten to try to be more
clear about the behaviour of i/o verification when verity is used.
Changes since v2:
* Rebased on top of overlayfs-next
* We now alway do verity verification the first time the file content
is used, rather than doing it at lookup time for the non-lazy lookup
case.
Changes since v1:
* Rebased on v2 lazy lowerdata series
* Dropped the "validate" mount option variant. We now only support
"off", "on" and "require", where "off" is the default.
* We now store the digest algorithm used in the overlay.verity xattr.
* Dropped ability to configure default verity options, as this could
cause problems moving layers between machines.
* We now properly resolve dependent mount options by automatically
enabling metacopy and redirect_dir if verity is on, or failing
if the specified options conflict.
* Streamlined and fixed the handling of creds in ovl_ensure_verity_loaded().
* Renamed new helpers from ovl_entry_path_ to ovl_e_path_
[1] https://github.com/alexlarsson/xfstests/commits/verity-tests
Alexander Larsson (3):
ovl: Add framework for verity support
ovl: Validate verity xattr when resolving lowerdata
ovl: Handle verity during copy-up
Documentation/filesystems/fsverity.rst | 2 +
Documentation/filesystems/overlayfs.rst | 48 ++++++++
fs/overlayfs/copy_up.c | 47 ++++++-
fs/overlayfs/file.c | 8 +-
fs/overlayfs/namei.c | 97 +++++++++++++--
fs/overlayfs/overlayfs.h | 53 ++++++--
fs/overlayfs/ovl_entry.h | 1 +
fs/overlayfs/super.c | 69 +++++++++--
fs/overlayfs/util.c | 156 +++++++++++++++++++++++-
9 files changed, 448 insertions(+), 33 deletions(-)
--
2.40.1
next reply other threads:[~2023-06-20 10:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 10:15 Alexander Larsson [this message]
2023-06-20 10:15 ` [PATCH v4 1/3] ovl: Add framework for verity support Alexander Larsson
2023-06-20 12:41 ` Amir Goldstein
2023-06-20 10:15 ` [PATCH v4 2/3] ovl: Validate verity xattr when resolving lowerdata Alexander Larsson
2023-06-20 13:50 ` Amir Goldstein
2023-06-20 10:15 ` [PATCH v4 3/3] ovl: Handle verity during copy-up Alexander Larsson
2023-06-20 12:10 ` Amir Goldstein
2023-06-20 16:15 ` [PATCH v4 0/3] ovl: Add support for fs-verity checking of lowerdata Eric Biggers
2023-06-21 11:27 ` Alexander Larsson
2023-06-21 12:57 ` Amir Goldstein
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