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Message-Id: <20220414135122.26821-5-lhenriques@suse.de>
Date: Thu, 14 Apr 2022 14:51:22 +0100
From: Luís Henriques <lhenriques@...e.de>
To: Jeff Layton <jlayton@...nel.org>, Xiubo Li <xiubli@...hat.com>,
Ilya Dryomov <idryomov@...il.com>
Cc: ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
Luís Henriques <lhenriques@...e.de>
Subject: [PATCH v4 4/4] ceph: replace base64url by the encoding used for mailbox names
The base64url encoding includes the '_' character, which may cause problems
in snapshot names (if the name starts with '_'). Thus, use the base64
encoding defined for IMAP mailbox names (RFC 3501), which uses '+' and ','
instead of '-' and '_'.
Signed-off-by: Luís Henriques <lhenriques@...e.de>
---
fs/ceph/crypto.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++--
fs/ceph/crypto.h | 3 +++
fs/ceph/dir.c | 2 +-
fs/ceph/inode.c | 2 +-
4 files changed, 67 insertions(+), 4 deletions(-)
diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index 1fa9dd634a6f..1adf97b00a4f 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -1,4 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
+/*
+ * The base64 encode/decode code was copied from fscrypt:
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility
+ * Written by Uday Savagaonkar, 2014.
+ * Modified by Jaegeuk Kim, 2015.
+ */
#include <linux/ceph/ceph_debug.h>
#include <linux/xattr.h>
#include <linux/fscrypt.h>
@@ -8,6 +15,59 @@
#include "mds_client.h"
#include "crypto.h"
+/*
+ * The base64url encoding used by fscrypt includes the '_' character, which may
+ * cause problems in snapshot names (which can not starts with '_'). Thus, we
+ * used the base64 encoding defined for IMAP mailbox names (RFC 3501) instead,
+ * which replaces '-' and '_' by '+' and ','.
+ */
+static const char base64_table[65] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
+
+int ceph_base64_encode(const u8 *src, int srclen, char *dst)
+{
+ u32 ac = 0;
+ int bits = 0;
+ int i;
+ char *cp = dst;
+
+ for (i = 0; i < srclen; i++) {
+ ac = (ac << 8) | src[i];
+ bits += 8;
+ do {
+ bits -= 6;
+ *cp++ = base64_table[(ac >> bits) & 0x3f];
+ } while (bits >= 6);
+ }
+ if (bits)
+ *cp++ = base64_table[(ac << (6 - bits)) & 0x3f];
+ return cp - dst;
+}
+
+int ceph_base64_decode(const char *src, int srclen, u8 *dst)
+{
+ u32 ac = 0;
+ int bits = 0;
+ int i;
+ u8 *bp = dst;
+
+ for (i = 0; i < srclen; i++) {
+ const char *p = strchr(base64_table, src[i]);
+
+ if (p == NULL || src[i] == 0)
+ return -1;
+ ac = (ac << 6) | (p - base64_table);
+ bits += 6;
+ if (bits >= 8) {
+ bits -= 8;
+ *bp++ = (u8)(ac >> bits);
+ }
+ }
+ if (ac & ((1 << bits) - 1))
+ return -1;
+ return bp - dst;
+}
+
static int ceph_crypt_get_context(struct inode *inode, void *ctx, size_t len)
{
struct ceph_inode_info *ci = ceph_inode(inode);
@@ -261,7 +321,7 @@ int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name, char
}
/* base64 encode the encrypted name */
- elen = fscrypt_base64url_encode(cryptbuf, len, buf);
+ elen = ceph_base64_encode(cryptbuf, len, buf);
dout("base64-encoded ciphertext name = %.*s\n", elen, buf);
/* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */
@@ -367,7 +427,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
tname = &_tname;
}
- declen = fscrypt_base64url_decode(name, name_len, tname->name);
+ declen = ceph_base64_decode(name, name_len, tname->name);
if (declen <= 0) {
ret = -EIO;
goto out;
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index 0e10f934af5c..63fb230fcb41 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -89,6 +89,9 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa)
*/
#define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE)
+int ceph_base64_encode(const u8 *src, int srclen, char *dst);
+int ceph_base64_decode(const char *src, int srclen, u8 *dst);
+
void ceph_fscrypt_set_ops(struct super_block *sb);
void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc);
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 5ccf6453f02f..f48f1ff20927 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -966,7 +966,7 @@ static int prep_encrypted_symlink_target(struct ceph_mds_request *req, const cha
goto out;
}
- len = fscrypt_base64url_encode(osd_link.name, osd_link.len, req->r_path2);
+ len = ceph_base64_encode(osd_link.name, osd_link.len, req->r_path2);
req->r_path2[len] = '\0';
out:
fscrypt_fname_free_buffer(&osd_link);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 8e97efa2b1a7..1df2eab767ef 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -876,7 +876,7 @@ static int decode_encrypted_symlink(const char *encsym, int enclen, u8 **decsym)
if (!sym)
return -ENOMEM;
- declen = fscrypt_base64url_decode(encsym, enclen, sym);
+ declen = ceph_base64_decode(encsym, enclen, sym);
if (declen < 0) {
pr_err("%s: can't decode symlink (%d). Content: %.*s\n",
__func__, declen, enclen, encsym);
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