From: xiubli@redhat.com
To: idryomov@gmail.com, ceph-devel@vger.kernel.org
Cc: jlayton@kernel.org, lhenriques@suse.de, vshankar@redhat.com,
mchangir@redhat.com, Xiubo Li <xiubli@redhat.com>
Subject: [PATCH v16 19/68] ceph: add base64 endcoding routines for encrypted names
Date: Mon, 27 Feb 2023 11:27:24 +0800 [thread overview]
Message-ID: <20230227032813.337906-20-xiubli@redhat.com> (raw)
In-Reply-To: <20230227032813.337906-1-xiubli@redhat.com>
From: Luís Henriques <lhenriques@suse.de>
The base64url encoding used by fscrypt 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@suse.de>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/crypto.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/ceph/crypto.h | 32 ++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index fd3192917e8d..947ac98119aa 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>
@@ -7,6 +14,59 @@
#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);
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index cb00fe42d5b7..f5d38d8a1995 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -27,6 +27,38 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa)
}
#ifdef CONFIG_FS_ENCRYPTION
+/*
+ * We want to encrypt filenames when creating them, but the encrypted
+ * versions of those names may have illegal characters in them. To mitigate
+ * that, we base64 encode them, but that gives us a result that can exceed
+ * NAME_MAX.
+ *
+ * Follow a similar scheme to fscrypt itself, and cap the filename to a
+ * smaller size. If the ciphertext name is longer than the value below, then
+ * sha256 hash the remaining bytes.
+ *
+ * For the fscrypt_nokey_name struct the dirhash[2] member is useless in ceph
+ * so the corresponding struct will be:
+ *
+ * struct fscrypt_ceph_nokey_name {
+ * u8 bytes[157];
+ * u8 sha256[SHA256_DIGEST_SIZE];
+ * }; // 180 bytes => 240 bytes base64-encoded, which is <= NAME_MAX (255)
+ *
+ * (240 bytes is the maximum size allowed for snapshot names to take into
+ * account the format: '_<SNAPSHOT-NAME>_<INODE-NUMBER>'.)
+ *
+ * Note that for long names that end up having their tail portion hashed, we
+ * must also store the full encrypted name (in the dentry's alternate_name
+ * field).
+ */
+#define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE)
+
+#define CEPH_BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
+
+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);
--
2.31.1
next prev parent reply other threads:[~2023-02-27 3:30 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-27 3:27 [PATCH v16 00/68] ceph+fscrypt: full support xiubli
2023-02-27 3:27 ` [PATCH v16 01/68] libceph: add spinlock around osd->o_requests xiubli
2023-02-27 3:27 ` [PATCH v16 02/68] libceph: define struct ceph_sparse_extent and add some helpers xiubli
2023-02-27 3:27 ` [PATCH v16 03/68] libceph: add sparse read support to msgr2 crc state machine xiubli
2023-02-27 3:27 ` [PATCH v16 04/68] libceph: add sparse read support to OSD client xiubli
2023-02-27 3:27 ` [PATCH v16 05/68] libceph: support sparse reads on msgr2 secure codepath xiubli
2023-02-27 3:27 ` [PATCH v16 06/68] libceph: add sparse read support to msgr1 xiubli
2023-02-27 3:27 ` [PATCH v16 07/68] ceph: add new mount option to enable sparse reads xiubli
2023-02-27 3:27 ` [PATCH v16 08/68] ceph: preallocate inode for ops that may create one xiubli
2023-02-27 3:27 ` [PATCH v16 09/68] ceph: make ceph_msdc_build_path use ref-walk xiubli
2023-02-27 3:27 ` [PATCH v16 10/68] libceph: add new iov_iter-based ceph_msg_data_type and ceph_osd_data_type xiubli
2023-02-27 3:27 ` [PATCH v16 11/68] ceph: use osd_req_op_extent_osd_iter for netfs reads xiubli
2023-02-27 3:27 ` [PATCH v16 12/68] ceph: fscrypt_auth handling for ceph xiubli
2023-02-27 3:27 ` [PATCH v16 13/68] ceph: ensure that we accept a new context from MDS for new inodes xiubli
2023-02-27 3:27 ` [PATCH v16 14/68] ceph: add support for fscrypt_auth/fscrypt_file to cap messages xiubli
2023-02-27 3:27 ` [PATCH v16 15/68] ceph: implement -o test_dummy_encryption mount option xiubli
2023-02-27 3:27 ` [PATCH v16 16/68] ceph: decode alternate_name in lease info xiubli
2023-02-27 3:27 ` [PATCH v16 17/68] ceph: add fscrypt ioctls xiubli
2023-02-27 3:27 ` [PATCH v16 18/68] ceph: make the ioctl cmd more readable in debug log xiubli
2023-02-27 3:27 ` xiubli [this message]
2023-02-27 3:27 ` [PATCH v16 20/68] ceph: add encrypted fname handling to ceph_mdsc_build_path xiubli
2023-02-27 3:27 ` [PATCH v16 21/68] ceph: send altname in MClientRequest xiubli
2023-02-27 3:27 ` [PATCH v16 22/68] ceph: encode encrypted name in dentry release xiubli
2023-02-27 3:27 ` [PATCH v16 23/68] ceph: properly set DCACHE_NOKEY_NAME flag in lookup xiubli
2023-02-27 3:27 ` [PATCH v16 24/68] ceph: set DCACHE_NOKEY_NAME in atomic open xiubli
2023-02-27 3:27 ` [PATCH v16 25/68] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries xiubli
2023-03-07 18:53 ` Luís Henriques
2023-03-08 1:50 ` Xiubo Li
2023-03-08 9:29 ` Luís Henriques
2023-03-08 10:42 ` Xiubo Li
2023-03-08 17:14 ` Luís Henriques
2023-03-08 17:54 ` Jeff Layton
2023-03-08 18:30 ` Luís Henriques
2023-03-08 19:32 ` Jeff Layton
2023-03-09 9:52 ` Luís Henriques
2023-03-09 7:06 ` Xiubo Li
2023-03-09 9:55 ` Luís Henriques
2023-03-09 11:41 ` Xiubo Li
2023-02-27 3:27 ` [PATCH v16 26/68] ceph: add helpers for converting names for userland presentation xiubli
2023-02-27 3:27 ` [PATCH v16 27/68] ceph: fix base64 encoded name's length check in ceph_fname_to_usr() xiubli
2023-02-27 3:27 ` [PATCH v16 28/68] ceph: add fscrypt support to ceph_fill_trace xiubli
2023-02-27 3:27 ` [PATCH v16 29/68] ceph: pass the request to parse_reply_info_readdir() xiubli
2023-02-27 3:27 ` [PATCH v16 30/68] ceph: add ceph_encode_encrypted_dname() helper xiubli
2023-02-27 3:27 ` [PATCH v16 31/68] ceph: add support to readdir for encrypted filenames xiubli
2023-02-27 3:27 ` [PATCH v16 32/68] ceph: create symlinks with encrypted and base64-encoded targets xiubli
2023-02-27 3:27 ` [PATCH v16 33/68] ceph: make ceph_get_name decrypt filenames xiubli
2023-02-27 3:27 ` [PATCH v16 34/68] ceph: add a new ceph.fscrypt.auth vxattr xiubli
2023-02-27 3:27 ` [PATCH v16 35/68] ceph: add some fscrypt guardrails xiubli
2023-02-27 3:27 ` [PATCH v16 36/68] ceph: allow encrypting a directory while not having Ax caps xiubli
2023-02-27 3:27 ` [PATCH v16 37/68] ceph: mark directory as non-complete after loading key xiubli
2023-02-27 3:27 ` [PATCH v16 38/68] ceph: don't allow changing layout on encrypted files/directories xiubli
2023-02-27 3:27 ` [PATCH v16 39/68] libceph: add CEPH_OSD_OP_ASSERT_VER support xiubli
2023-02-27 3:27 ` [PATCH v16 40/68] ceph: size handling for encrypted inodes in cap updates xiubli
2023-02-27 3:27 ` [PATCH v16 41/68] ceph: fscrypt_file field handling in MClientRequest messages xiubli
2023-02-27 3:27 ` [PATCH v16 42/68] ceph: get file size from fscrypt_file when present in inode traces xiubli
2023-02-27 3:27 ` [PATCH v16 43/68] ceph: handle fscrypt fields in cap messages from MDS xiubli
2023-02-27 3:27 ` [PATCH v16 44/68] ceph: update WARN_ON message to pr_warn xiubli
2023-02-27 3:27 ` [PATCH v16 45/68] ceph: add __ceph_get_caps helper support xiubli
2023-02-27 3:27 ` [PATCH v16 46/68] ceph: add __ceph_sync_read " xiubli
2023-02-27 3:27 ` [PATCH v16 47/68] ceph: add object version support for sync read xiubli
2023-02-27 3:27 ` [PATCH v16 48/68] ceph: add infrastructure for file encryption and decryption xiubli
2023-02-27 3:27 ` [PATCH v16 49/68] ceph: add truncate size handling support for fscrypt xiubli
2023-02-27 3:27 ` [PATCH v16 50/68] libceph: allow ceph_osdc_new_request to accept a multi-op read xiubli
2023-02-27 3:27 ` [PATCH v16 51/68] ceph: disable fallocate for encrypted inodes xiubli
2023-02-27 3:27 ` [PATCH v16 52/68] ceph: disable copy offload on " xiubli
2023-02-27 3:27 ` [PATCH v16 53/68] ceph: don't use special DIO path for " xiubli
2023-02-27 3:27 ` [PATCH v16 54/68] ceph: align data in pages in ceph_sync_write xiubli
2023-02-27 3:28 ` [PATCH v16 55/68] ceph: add read/modify/write to ceph_sync_write xiubli
2023-02-27 3:28 ` [PATCH v16 56/68] ceph: plumb in decryption during sync reads xiubli
2023-02-27 3:28 ` [PATCH v16 57/68] ceph: add fscrypt decryption support to ceph_netfs_issue_op xiubli
2023-02-27 3:28 ` [PATCH v16 58/68] ceph: set i_blkbits to crypto block size for encrypted inodes xiubli
2023-02-27 3:28 ` [PATCH v16 59/68] ceph: add encryption support to writepage xiubli
2023-02-27 3:28 ` [PATCH v16 60/68] ceph: fscrypt support for writepages xiubli
2023-02-27 3:28 ` [PATCH v16 61/68] ceph: invalidate pages when doing direct/sync writes xiubli
2023-02-27 3:28 ` [PATCH v16 62/68] ceph: add support for encrypted snapshot names xiubli
2023-02-27 3:28 ` [PATCH v16 63/68] ceph: add support for handling " xiubli
2023-02-27 3:28 ` [PATCH v16 64/68] ceph: update documentation regarding snapshot naming limitations xiubli
2023-02-27 3:28 ` [PATCH v16 65/68] ceph: prevent snapshots to be created in encrypted locked directories xiubli
2023-02-27 3:28 ` [PATCH v16 66/68] ceph: report STATX_ATTR_ENCRYPTED on encrypted inodes xiubli
2023-02-27 3:28 ` [PATCH v16 67/68] libceph: defer removing the req from osdc just after req->r_callback xiubli
2023-02-27 3:28 ` [PATCH v16 68/68] ceph: drop the messages from MDS when unmounting xiubli
2023-02-27 9:27 ` [PATCH v16 00/68] ceph+fscrypt: full support Luís Henriques
2023-02-27 9:58 ` Xiubo Li
2023-02-27 10:30 ` Luís Henriques
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