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[0/6] fsverity: support for non-4K pages

Message ID 20221028224539.171818-1-ebiggers@kernel.org (mailing list archive)
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Series fsverity: support for non-4K pages | expand

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Eric Biggers Oct. 28, 2022, 10:45 p.m. UTC 
[This patchset applies to v6.1-rc2 + my other patch
 https://lore.kernel.org/r/20221028175807.55495-1-ebiggers@kernel.org.
 You can get everything from tag "fsverity-non4k-v1" of
 https://git.kernel.org/pub/scm/fs/fscrypt/fscrypt.git]

Currently, filesystems (ext4, f2fs, and btrfs) only support fsverity
when the Merkle tree block size, filesystem block size, and page size
are all the same.  In practice that means 4K, since increasing the page
size, e.g. to 16K, forces the Merkle tree block size and filesystem
block size to be increased accordingly.  That can be impractical; for
one, users want the same file signatures to work on all systems.

Therefore, this patchset reduces the coupling between these sizes.

First, patches 1-4 allow the Merkle tree block size to be less than the
page size or filesystem block size, provided that it's not larger than
either one.  This involves, among other things, changing the way that
fs/verity/verify.c tracks which hash blocks have been verified.

Second, patches 5-6 makes ext4 support fsverity when the filesystem
block size is less than the page size.  Note, f2fs doesn't need similar
changes because f2fs always assumes that the filesystem block size and
page size are the same anyway.  I haven't looked into btrfs yet.

I've tested this patchset with changes to the verity tests in xfstests.
I'll be sending out these xfstests changes separately.

Eric Biggers (6):
  fsverity: support verification with tree block size < PAGE_SIZE
  fsverity: support enabling with tree block size < PAGE_SIZE
  ext4: simplify ext4_readpage_limit()
  f2fs: simplify f2fs_readpage_limit()
  fs/buffer.c: support fsverity in block_read_full_folio()
  ext4: allow verity with fs block size < PAGE_SIZE

 Documentation/filesystems/fsverity.rst |  76 +++---
 fs/buffer.c                            |  66 ++++-
 fs/ext4/readpage.c                     |   3 +-
 fs/ext4/super.c                        |   5 -
 fs/f2fs/data.c                         |   3 +-
 fs/verity/enable.c                     | 268 ++++++++++----------
 fs/verity/fsverity_private.h           |  17 +-
 fs/verity/hash_algs.c                  |  48 ++--
 fs/verity/open.c                       | 101 ++++++--
 fs/verity/verify.c                     | 325 +++++++++++++++++--------
 include/linux/fsverity.h               |  14 +-
 11 files changed, 575 insertions(+), 351 deletions(-)