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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 14/18] ceph: add encrypted fname handling to ceph_mdsc_build_path
Date: Mon, 7 Sep 2020 22:06:43 -0700
Message-ID: <20200908050643.GL68127@sol.localdomain> (raw)
In-Reply-To: <20200904160537.76663-15-jlayton@kernel.org>

On Fri, Sep 04, 2020 at 12:05:33PM -0400, Jeff Layton wrote:
> Allow ceph_mdsc_build_path to encrypt and base64 encode the filename
> when the parent is encrypted and we're sending the path to the MDS.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/ceph/mds_client.c | 51 ++++++++++++++++++++++++++++++++++----------
>  1 file changed, 40 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index e3dc061252d4..26b43ae09823 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -11,6 +11,7 @@
>  #include <linux/ratelimit.h>
>  #include <linux/bits.h>
>  #include <linux/ktime.h>
> +#include <linux/base64_fname.h>
>  
>  #include "super.h"
>  #include "mds_client.h"
> @@ -2324,8 +2325,7 @@ static inline  u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
>   * Encode hidden .snap dirs as a double /, i.e.
>   *   foo/.snap/bar -> foo//bar
>   */
> -char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
> -			   int stop_on_nosnap)
> +char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for_wire)
>  {
>  	struct dentry *cur;
>  	struct inode *inode;
> @@ -2347,30 +2347,59 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
>  	seq = read_seqbegin(&rename_lock);
>  	cur = dget(dentry);
>  	for (;;) {
> -		struct dentry *temp;
> +		struct dentry *parent;
>  
>  		spin_lock(&cur->d_lock);
>  		inode = d_inode(cur);
> +		parent = cur->d_parent;
>  		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
>  			dout("build_path path+%d: %p SNAPDIR\n",
>  			     pos, cur);
> -		} else if (stop_on_nosnap && inode && dentry != cur &&
> -			   ceph_snap(inode) == CEPH_NOSNAP) {
> +			dget(parent);
> +			spin_unlock(&cur->d_lock);
> +		} else if (for_wire && inode && dentry != cur && ceph_snap(inode) == CEPH_NOSNAP) {
>  			spin_unlock(&cur->d_lock);
>  			pos++; /* get rid of any prepended '/' */
>  			break;
> -		} else {
> +		} else if (!for_wire || !IS_ENCRYPTED(d_inode(parent))) {
>  			pos -= cur->d_name.len;
>  			if (pos < 0) {
>  				spin_unlock(&cur->d_lock);
>  				break;
>  			}
>  			memcpy(path + pos, cur->d_name.name, cur->d_name.len);
> +			dget(parent);
> +			spin_unlock(&cur->d_lock);
> +		} else {
> +			int err;
> +			struct fscrypt_name fname = { };
> +			int len;
> +			char buf[BASE64_CHARS(NAME_MAX)];
> +
> +			dget(parent);
> +			spin_unlock(&cur->d_lock);
> +
> +			err = fscrypt_setup_filename(d_inode(parent), &cur->d_name, 1, &fname);

How are no-key filenames handled with ceph?  You're calling
fscrypt_setup_filename() with lookup=1, so it will give you back a no-key
filename if the directory's encryption key is unavailable.

> +			if (err) {
> +				dput(parent);
> +				dput(cur);
> +				return ERR_PTR(err);
> +			}
> +
> +			/* base64 encode the encrypted name */
> +			len = base64_encode_fname(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 would be easier to understand if the encryption and encoding logic was
moved into its own function.

- 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
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 [this message]
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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