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From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	dhowells@redhat.com, xiubli@redhat.com, lhenriques@suse.de,
	khiremat@redhat.com, ebiggers@kernel.org
Subject: [RFC PATCH v8 02/24] fscrypt: export fscrypt_base64url_encode and fscrypt_base64url_decode
Date: Thu, 26 Aug 2021 12:19:52 -0400	[thread overview]
Message-ID: <20210826162014.73464-3-jlayton@kernel.org> (raw)
In-Reply-To: <20210826162014.73464-1-jlayton@kernel.org>

Ceph is going to add fscrypt support, but we still want encrypted
filenames to be composed of printable characters, so we can maintain
compatibility with clients that don't support fscrypt.

We could just adopt fscrypt's current nokey name format, but that is
subject to change in the future, and it also contains dirhash fields
that we don't need for cephfs. Because of this, we're going to concoct
our own scheme for encoding encrypted filenames. It's very similar to
fscrypt's current scheme, but doesn't bother with the dirhash fields.

The ceph encoding scheme will use base64 encoding as well, and we also
want it to avoid characters that are illegal in filenames. Export the
fscrypt base64 encoding/decoding routines so we can use them in ceph's
fscrypt implementation.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/crypto/fname.c       | 8 ++++----
 include/linux/fscrypt.h | 5 +++++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index c61fc3708c64..02555a31875a 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -182,8 +182,6 @@ static int fname_decrypt(const struct inode *inode,
 static const char base64url_table[65] =
 	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
 
-#define FSCRYPT_BASE64URL_CHARS(nbytes)	DIV_ROUND_UP((nbytes) * 4, 3)
-
 /**
  * fscrypt_base64url_encode() - base64url-encode some binary data
  * @src: the binary data to encode
@@ -198,7 +196,7 @@ static const char base64url_table[65] =
  * Return: length of the resulting base64url-encoded string in bytes.
  *	   This will be equal to FSCRYPT_BASE64URL_CHARS(srclen).
  */
-static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
+int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
 {
 	u32 ac = 0;
 	int bits = 0;
@@ -217,6 +215,7 @@ static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
 		*cp++ = base64url_table[(ac << (6 - bits)) & 0x3f];
 	return cp - dst;
 }
+EXPORT_SYMBOL(fscrypt_base64url_encode);
 
 /**
  * fscrypt_base64url_decode() - base64url-decode a string
@@ -233,7 +232,7 @@ static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
  * Return: the length of the resulting decoded binary data in bytes,
  *	   or -1 if the string isn't a valid base64url string.
  */
-static int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst)
+int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst)
 {
 	u32 ac = 0;
 	int bits = 0;
@@ -256,6 +255,7 @@ static int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst)
 		return -1;
 	return bp - dst;
 }
+EXPORT_SYMBOL(fscrypt_base64url_decode);
 
 bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
 				  u32 orig_len, u32 max_len,
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 2ea1387bb497..07144330f975 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -46,6 +46,9 @@ struct fscrypt_name {
 /* Maximum value for the third parameter of fscrypt_operations.set_context(). */
 #define FSCRYPT_SET_CONTEXT_MAX_SIZE	40
 
+/* len of resulting string (sans NUL terminator) after base64 encoding nbytes */
+#define FSCRYPT_BASE64URL_CHARS(nbytes)		DIV_ROUND_UP((nbytes) * 4, 3)
+
 #ifdef CONFIG_FS_ENCRYPTION
 /*
  * fscrypt superblock flags
@@ -207,6 +210,8 @@ void fscrypt_free_inode(struct inode *inode);
 int fscrypt_drop_inode(struct inode *inode);
 
 /* fname.c */
+int fscrypt_base64url_encode(const u8 *src, int len, char *dst);
+int fscrypt_base64url_decode(const char *src, int len, u8 *dst);
 int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
 			   int lookup, struct fscrypt_name *fname);
 
-- 
2.31.1


  parent reply	other threads:[~2021-08-26 16:20 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 16:19 [RFC PATCH v8 00/24] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 01/24] vfs: export new_inode_pseudo Jeff Layton
2021-08-26 16:19 ` Jeff Layton [this message]
2021-08-26 16:19 ` [RFC PATCH v8 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 04/24] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 05/24] ceph: preallocate inode for ops that may create one Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 06/24] ceph: parse new fscrypt_auth and fscrypt_file fields in inode traces Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 07/24] ceph: add fscrypt_* handling to caps.c Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 08/24] ceph: crypto context handling for ceph Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 09/24] ceph: add ability to set fscrypt_auth via setattr Jeff Layton
2021-08-31  5:06   ` Xiubo Li
2021-08-31 12:43     ` Jeff Layton
2021-08-31 13:22       ` Xiubo Li
2021-08-31 13:50         ` Jeff Layton
2021-08-31 17:54           ` Eric Biggers
2021-09-01  0:53             ` Xiubo Li
2021-09-01  1:13           ` Xiubo Li
2021-09-01 12:02             ` Jeff Layton
2021-09-02  1:54               ` Xiubo Li
2021-08-26 16:20 ` [RFC PATCH v8 10/24] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 11/24] ceph: add fscrypt ioctls Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 12/24] ceph: decode alternate_name in lease info Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 13/24] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 14/24] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 15/24] ceph: send altname in MClientRequest Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 16/24] ceph: encode encrypted name in dentry release Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 17/24] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 18/24] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 19/24] ceph: add helpers for converting names for userland presentation Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 20/24] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 21/24] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 22/24] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 23/24] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 24/24] ceph: add a new ceph.fscrypt.auth vxattr Jeff Layton

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