From: Jeff Layton <jlayton@kernel.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: ceph-devel@vger.kernel.org, lhenriques@suse.de,
xiubli@redhat.com, linux-fsdevel@vger.kernel.org,
linux-fscrypt@vger.kernel.org, dhowells@redhat.com
Subject: Re: [RFC PATCH v7 02/24] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode
Date: Mon, 12 Jul 2021 10:32:21 -0400 [thread overview]
Message-ID: <48fd676431f1589e8fc1cbc27c8ec011498de6c5.camel@kernel.org> (raw)
In-Reply-To: <YOxQKyZtWgFZ85YK@quark.localdomain>
On Mon, 2021-07-12 at 09:22 -0500, Eric Biggers wrote:
> On Mon, Jul 12, 2021 at 07:55:37AM -0400, Jeff Layton wrote:
> > On Sun, 2021-07-11 at 12:40 -0500, Eric Biggers wrote:
> > > Some nits about comments:
> > >
> > > On Fri, Jun 25, 2021 at 09:58:12AM -0400, Jeff Layton wrote:
> > > > diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
> > > > index 6ca7d16593ff..32b1f50433ba 100644
> > > > --- a/fs/crypto/fname.c
> > > > +++ b/fs/crypto/fname.c
> > > > @@ -178,10 +178,8 @@ static int fname_decrypt(const struct inode *inode,
> > > > static const char lookup_table[65] =
> > > > "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
> > > >
> > > > -#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
> > > > -
> > > > /**
> > > > - * base64_encode() - base64-encode some bytes
> > > > + * fscrypt_base64_encode() - base64-encode some bytes
> > > > * @src: the bytes to encode
> > > > * @len: number of bytes to encode
> > > > * @dst: (output) the base64-encoded string. Not NUL-terminated.
> > > > *
> > > > * Encodes the input string using characters from the set [A-Za-z0-9+,].
> > > > * The encoded string is roughly 4/3 times the size of the input string.
> > > > *
> > > > * Return: length of the encoded string
> > > > */
> > > > -static int base64_encode(const u8 *src, int len, char *dst)
> > > > +int fscrypt_base64_encode(const u8 *src, int len, char *dst)
> > >
> > > As this function will be used more widely, this comment should be fixed to be
> > > more precise. "Roughly 4/3" isn't precise; it's actually exactly
> > > FSCRYPT_BASE64_CHARS(len), right? The following would be better:
> > >
> > > * Encode the input bytes using characters from the set [A-Za-z0-9+,].
> > > *
> > > * Return: length of the encoded string. This will be equal to
> > > * FSCRYPT_BASE64_CHARS(len).
> > >
> >
> > I'm not certain, but I thought that FSCRYPT_BASE64_CHARS gave you a
> > worst-case estimate of the inflation. This returns the actual length of
> > the resulting encoded string, which may be less than
> > FSCRYPT_BASE64_CHARS(len).
> >
>
> As far as I can tell, it's the exact amount.
Yeah, now that I went back and re-read the code, I think you're right.
I'll fix the comment.
Thanks,
--
Jeff Layton <jlayton@kernel.org>
next prev parent reply other threads:[~2021-07-12 14:32 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 13:58 [RFC PATCH v7 00/24] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 01/24] vfs: export new_inode_pseudo Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 02/24] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Jeff Layton
2021-07-11 17:40 ` Eric Biggers
2021-07-12 11:55 ` Jeff Layton
2021-07-12 14:22 ` Eric Biggers
2021-07-12 14:32 ` Jeff Layton [this message]
2021-06-25 13:58 ` [RFC PATCH v7 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
2021-07-11 17:43 ` Eric Biggers
2021-06-25 13:58 ` [RFC PATCH v7 04/24] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-07-11 17:44 ` Eric Biggers
2021-06-25 13:58 ` [RFC PATCH v7 05/24] ceph: preallocate inode for ops that may create one Jeff Layton
2021-07-07 3:37 ` Xiubo Li
2021-07-07 12:05 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 06/24] ceph: parse new fscrypt_auth and fscrypt_file fields in inode traces Jeff Layton
2021-07-07 3:53 ` Xiubo Li
2021-07-07 12:09 ` Jeff Layton
2021-07-07 12:46 ` Xiubo Li
2021-07-07 10:47 ` Luis Henriques
2021-07-07 11:19 ` Xiubo Li
2021-07-07 12:19 ` Jeff Layton
2021-07-07 14:32 ` Luis Henriques
2021-07-07 14:56 ` Luis Henriques
2021-07-08 2:56 ` Xiubo Li
2021-07-08 11:26 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 07/24] ceph: add fscrypt_* handling to caps.c Jeff Layton
2021-07-07 7:20 ` Xiubo Li
2021-07-07 12:02 ` Jeff Layton
2021-07-07 12:47 ` Xiubo Li
2021-07-11 23:00 ` Eric Biggers
2021-07-12 13:22 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 08/24] ceph: add ability to set fscrypt_auth via setattr Jeff Layton
2021-07-07 8:11 ` Xiubo Li
2021-07-07 12:10 ` Jeff Layton
2021-07-07 10:47 ` Luis Henriques
2021-07-07 12:25 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 09/24] ceph: crypto context handling for ceph Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 10/24] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 11/24] ceph: add routine to create fscrypt context prior to RPC Jeff Layton
2021-07-07 10:48 ` Luis Henriques
2021-07-07 12:29 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 12/24] ceph: add fscrypt ioctls Jeff Layton
2021-07-08 7:30 ` Xiubo Li
2021-07-08 11:26 ` Jeff Layton
2021-07-08 11:32 ` Xiubo Li
2021-06-25 13:58 ` [RFC PATCH v7 13/24] ceph: decode alternate_name in lease info Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 14/24] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 15/24] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-07-11 22:53 ` Eric Biggers
2021-07-12 12:36 ` Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 16/24] ceph: send altname in MClientRequest Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 17/24] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 18/24] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 19/24] ceph: add helpers for converting names for userland presentation Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 20/24] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 21/24] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 22/24] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 23/24] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-06-25 13:58 ` [RFC PATCH v7 24/24] ceph: add a new ceph.fscrypt.auth vxattr Jeff Layton
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