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From: Jeff Layton <jlayton@kernel.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: ceph-devel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, Xiubo Li <xiubli@redhat.com>
Subject: Re: [RFC PATCH v3 12/16] ceph: add encrypted fname handling to ceph_mdsc_build_path
Date: Wed, 16 Sep 2020 08:30:01 -0400	[thread overview]
Message-ID: <bd9257732cfd98ee30ccc151125d21d6955d6f66.camel@kernel.org> (raw)
In-Reply-To: <20200915014159.GK899@sol.localdomain>

On Mon, 2020-09-14 at 18:41 -0700, Eric Biggers wrote:
> On Mon, Sep 14, 2020 at 03:17:03PM -0400, Jeff Layton wrote:
> > +		} else {
> > +			int err;
> > +			struct fscrypt_name fname = { };
> > +			int len;
> > +			char buf[FSCRYPT_BASE64_CHARS(NAME_MAX)];
> > +
> > +			dget(parent);
> > +			spin_unlock(&cur->d_lock);
> > +
> > +			err = fscrypt_setup_filename(d_inode(parent), &cur->d_name, 1, &fname);
> > +			if (err) {
> > +				dput(parent);
> > +				dput(cur);
> > +				return ERR_PTR(err);
> > +			}
> 
> It's still not clear how no-key names are handled here (or if they are even
> possible here).
> 

They're not really handled yet. We need support in the MDS for it, which
is being worked on by Xiubo (cc'ed):

    https://tracker.ceph.com/issues/47162

For now, working with names > ~149 characters can leave you with bad
dentries that the client may not be able to work with if you don't have
the key.

It sounds like we'll probably need to stabilize some version of the
nokey name so that we can allow the MDS to look them up. Would it be a
problem for us to use the current version of the nokey name format for
this, or would it be better to come up with some other distinct format
for this?

Using the current version of the nokey name is simple as we can just
pass it as-is to the MDS if someone is working in a directory w/o keys.

> > +
> > +			/* base64 encode the encrypted name */
> > +			len = fscrypt_base64_encode(fname.disk_name.name, fname.disk_name.len, buf);
> > +			pos -= len;
> > +			if (pos < 0) {
> > +				dput(parent);
> > +				fscrypt_free_filename(&fname);
> > +				break;
> > +			}
> > +			memcpy(path + pos, buf, len);
> > +			dout("non-ciphertext name = %.*s\n", len, buf);
> > +			fscrypt_free_filename(&fname);
> 
> This says "non-ciphertext name", which suggest that it's a plaintext name.  But
> actually it's a base64-encoded ciphertext name.
> 

Thanks. I fixed the comment.
-- 
Jeff Layton <jlayton@kernel.org>


  reply	other threads:[~2020-09-16 18:58 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 19:16 [RFC PATCH v3 00/16] ceph+fscrypt: context, filename and symlink support Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 01/16] vfs: export new_inode_pseudo Jeff Layton
2020-09-14 23:33   ` Eric Biggers
2020-09-23  3:41   ` Al Viro
2020-09-23 11:19     ` Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 02/16] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Jeff Layton
2020-09-14 23:44   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 03/16] fscrypt: export fscrypt_d_revalidate Jeff Layton
2020-09-15  0:04   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 04/16] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2020-09-15  0:15   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 05/16] fscrypt: make fscrypt_fname_disk_to_usr return whether result is nokey name Jeff Layton
2020-09-15  0:23   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 06/16] ceph: add fscrypt ioctls Jeff Layton
2020-09-15  0:45   ` Eric Biggers
2020-09-15 12:08     ` Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 07/16] ceph: crypto context handling for ceph Jeff Layton
2020-09-15  1:00   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 08/16] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2020-09-15  1:23   ` Eric Biggers
2020-09-16 12:49     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 09/16] ceph: preallocate inode for ops that may create one Jeff Layton
2020-09-15  1:30   ` Eric Biggers
2020-09-16 12:41     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 10/16] ceph: add routine to create context prior to RPC Jeff Layton
2020-09-15  1:37   ` Eric Biggers
2020-09-16 12:18     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 11/16] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 12/16] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2020-09-15  1:41   ` Eric Biggers
2020-09-16 12:30     ` Jeff Layton [this message]
2020-09-16 17:36       ` Eric Biggers
2020-09-16 18:04         ` Jeff Layton
2020-09-16 18:42           ` Eric Biggers
2020-09-14 19:17 ` [RFC PATCH v3 13/16] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 14/16] ceph: add support to readdir for encrypted filenames Jeff Layton
2020-09-15  1:57   ` Eric Biggers
2020-09-15 13:27     ` Jeff Layton
2020-09-15 20:40       ` Eric Biggers
2020-09-16 12:16         ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 15/16] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 16/16] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2020-09-15  2:07   ` Eric Biggers
2020-09-15 14:05     ` Jeff Layton
2020-09-15 20:49       ` Eric Biggers
2020-09-16 12:15         ` Jeff Layton
2020-09-15  2:13 ` [RFC PATCH v3 00/16] ceph+fscrypt: context, filename and symlink support Eric Biggers
2020-09-15 13:38   ` Jeff Layton

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