Re: [RFC PATCH v5 00/19] ceph+fscrypt: context, filename and symlink support

Jeff Layton
2021-03-26T18:38:46Z

On Fri, 2021-03-26 at 13:32 -0400, Jeff Layton wrote:
> I haven't posted this in a while and there were some bugs shaken out of
> the last posting. This adds (partial) support for fscrypt to kcephfs,
> including crypto contexts, filenames and encrypted symlink targets. At
> this point, the xfstests quick tests that generally pass without fscrypt
> also pass with test_dummy_encryption enabled.
>
> There is one lingering bug that I'm having trouble tracking down: xfstest
> generic/477 (an open_by_handle_at test) sometimes throws a "Busy inodes
> after umount" warning. I'm narrowed down the issue a bit, but there is
> some raciness involved so I haven't quite nailed it down yet.
>
> This set is quite invasive. There is probably some further work to be
> done to add common code helpers and the like, but the final diffstat
> probably won't look too different.
>
> This set does not include encryption of file contents. That is turning
> out to be a bit trickier than first expected owing to the fact that the
> MDS is usually what handles truncation, and the i_size no longer
> represents the amount of data stored in the backing store. That will
> probably require an MDS change to fix, and we're still sorting out the
> details.
>
> Jeff Layton (19):
> vfs: export new_inode_pseudo
> fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode
> fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size
> fscrypt: add fscrypt_context_for_new_inode
> ceph: crypto context handling for ceph
> ceph: implement -o test_dummy_encryption mount option
> ceph: preallocate inode for ops that may create one
> ceph: add routine to create fscrypt context prior to RPC
> ceph: make ceph_msdc_build_path use ref-walk
> ceph: add encrypted fname handling to ceph_mdsc_build_path
> ceph: decode alternate_name in lease info
> ceph: send altname in MClientRequest
> ceph: properly set DCACHE_NOKEY_NAME flag in lookup
> ceph: make d_revalidate call fscrypt revalidator for encrypted
> dentries
> ceph: add helpers for converting names for userland presentation
> ceph: add fscrypt support to ceph_fill_trace
> ceph: add support to readdir for encrypted filenames
> ceph: create symlinks with encrypted and base64-encoded targets
> ceph: add fscrypt ioctls
>
> fs/ceph/Makefile | 1 +
> fs/ceph/crypto.c | 185 +++++++++++++++++++++++
> fs/ceph/crypto.h | 101 +++++++++++++
> fs/ceph/dir.c | 178 ++++++++++++++++++-----
> fs/ceph/file.c | 56 ++++---
> fs/ceph/inode.c | 255 +++++++++++++++++++++++++++++---
> fs/ceph/ioctl.c | 94 ++++++++++++
> fs/ceph/mds_client.c | 283 ++++++++++++++++++++++++++++++------
> fs/ceph/mds_client.h | 14 +-
> fs/ceph/super.c | 80 +++++++++-
> fs/ceph/super.h | 16 +-
> fs/ceph/xattr.c | 32 ++++
> fs/crypto/fname.c | 53 +++++--
> fs/crypto/fscrypt_private.h | 9 +-
> fs/crypto/hooks.c | 6 +-
> fs/crypto/policy.c | 34 ++++-
> fs/inode.c | 1 +
> include/linux/fscrypt.h | 10 ++
> 18 files changed, 1246 insertions(+), 162 deletions(-)
> create mode 100644 fs/ceph/crypto.c
> create mode 100644 fs/ceph/crypto.h
>

Oh, I should mention that this is all in my ceph-fscrypt-fnames branch:

https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git/

This all still under heavy development, so I'm open to suggestions and
review. If you're daring and want to test with it, please do.

I do think this has the potential to be a "killer feature" for ceph (and
maybe other network filesystems). Being able to store data securely on
an otherwise "public" cluster seems like a very nice thing to have.

Cheers,
--
Jeff Layton <jlayton@kernel.org>