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From: Eric Biggers <ebiggers@kernel.org>
To: Jeff Layton <jlayton@kernel.org>
Cc: ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-fscrypt@vger.kernel.org
Subject: Re: [RFC PATCH v2 07/18] lib: lift fscrypt base64 conversion into lib/
Date: Mon, 7 Sep 2020 20:59:56 -0700
Message-ID: <20200908035956.GH68127@sol.localdomain> (raw)
In-Reply-To: <20200904160537.76663-8-jlayton@kernel.org>

On Fri, Sep 04, 2020 at 12:05:26PM -0400, Jeff Layton wrote:
> Once we allow encrypted filenames on ceph we'll end up with names that
> may have illegal characters in them (embedded '\0' or '/'), or
> characters that aren't printable.
> 
> It will be safer to use strings that are printable. It turns out that the
> MDS doesn't really care about the length of filenames, so we can just
> base64 encode and decode filenames before writing and reading them.
> 
> Lift the base64 implementation that's in fscrypt into lib/. Make fscrypt
> select it when it's enabled.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/crypto/Kconfig            |  1 +
>  fs/crypto/fname.c            | 64 ++------------------------------
>  include/linux/base64_fname.h | 11 ++++++
>  lib/Kconfig                  |  3 ++
>  lib/Makefile                 |  1 +
>  lib/base64_fname.c           | 71 ++++++++++++++++++++++++++++++++++++
>  6 files changed, 90 insertions(+), 61 deletions(-)
>  create mode 100644 include/linux/base64_fname.h
>  create mode 100644 lib/base64_fname.c
> 

I'm still concerned that this functionality is too specific to belong in lib/ at
the moment, given that it's not the most commonly used variant of base64.  How
about keeping these functions in fs/crypto/ for now?  You can call them
fscrypt_base64_encode() and fscrypt_base64_decode() and export them for ceph to
use.

> diff --git a/lib/base64_fname.c b/lib/base64_fname.c
> new file mode 100644
> index 000000000000..7638c45e4035
> --- /dev/null
> +++ b/lib/base64_fname.c
> @@ -0,0 +1,71 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Modified base64 encode/decode functions, suitable for use as filename components.
> + *
> + * Originally lifted from fs/crypto/fname.c
> + *
> + * Copyright (C) 2015, Jaegeuk Kim
> + * Copyright (C) 2015, Eric Biggers
> + */

Please don't change the copyright statements.  The original file had:

 * Copyright (C) 2015, Google, Inc.
 * Copyright (C) 2015, Motorola Mobility

- Eric

  reply index

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04 16:05 [RFC PATCH v2 00/18] ceph+fscrypt: context, filename and symlink support Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 01/18] vfs: export new_inode_pseudo Jeff Layton
2020-09-08  3:38   ` Eric Biggers
2020-09-08 11:27     ` Jeff Layton
2020-09-08 22:31       ` Eric Biggers
2020-09-09 10:47         ` Jeff Layton
2020-09-09 16:12           ` Eric Biggers
2020-09-09 16:51             ` Jeff Layton
2020-09-09 18:49               ` Eric Biggers
2020-09-09 19:24                 ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 02/18] fscrypt: drop unused inode argument from fscrypt_fname_alloc_buffer Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 03/18] fscrypt: export fscrypt_d_revalidate Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 04/18] fscrypt: add fscrypt_new_context_from_inode Jeff Layton
2020-09-08  3:48   ` Eric Biggers
2020-09-08 11:29     ` Jeff Layton
2020-09-08 12:29     ` Jeff Layton
2020-09-08 22:34       ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 05/18] fscrypt: don't balk when inode is already marked encrypted Jeff Layton
2020-09-08  3:52   ` Eric Biggers
2020-09-08 12:54     ` Jeff Layton
2020-09-08 23:08       ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 06/18] fscrypt: move nokey_name conversion to separate function and export it Jeff Layton
2020-09-08  3:55   ` Eric Biggers
2020-09-08 12:50     ` Jeff Layton
2020-09-08 22:53       ` Eric Biggers
2020-09-09 16:02         ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 07/18] lib: lift fscrypt base64 conversion into lib/ Jeff Layton
2020-09-08  3:59   ` Eric Biggers [this message]
2020-09-08 12:51     ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 08/18] ceph: add fscrypt ioctls Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 09/18] ceph: crypto context handling for ceph Jeff Layton
2020-09-08  4:29   ` Eric Biggers
2020-09-08 16:14     ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 10/18] ceph: preallocate inode for ops that may create one Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 11/18] ceph: add routine to create context prior to RPC Jeff Layton
2020-09-08  4:43   ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 12/18] ceph: set S_ENCRYPTED bit if new inode has encryption.ctx xattr Jeff Layton
2020-09-08  4:57   ` Eric Biggers
2020-09-09 12:20     ` Jeff Layton
2020-09-09 15:53     ` Jeff Layton
2020-09-09 16:33       ` Eric Biggers
2020-09-09 17:19         ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 13/18] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 14/18] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2020-09-08  5:06   ` Eric Biggers
2020-09-09 12:24     ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 15/18] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2020-09-08  5:12   ` Eric Biggers
2020-09-09 12:26     ` Jeff Layton
2020-09-09 16:18       ` Eric Biggers
2020-09-04 16:05 ` [RFC PATCH v2 16/18] ceph: add support to readdir for encrypted filenames Jeff Layton
2020-09-08  5:34   ` Eric Biggers
2020-09-09 13:02     ` Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 17/18] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2020-09-04 16:05 ` [RFC PATCH v2 18/18] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2020-09-04 16:11   ` Jeff Layton
2020-09-08  5:43   ` Eric Biggers
2020-09-08  5:54 ` [RFC PATCH v2 00/18] ceph+fscrypt: context, filename and symlink support Eric Biggers
2020-09-08 12:09   ` Jeff Layton

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