From patchwork Wed Apr 27 19:12:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 566777 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6E50C433F5 for ; Wed, 27 Apr 2022 19:24:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232878AbiD0T1w (ORCPT ); Wed, 27 Apr 2022 15:27:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233055AbiD0TTO (ORCPT ); Wed, 27 Apr 2022 15:19:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54D2C88B21 for ; Wed, 27 Apr 2022 12:13:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C1844619FC for ; Wed, 27 Apr 2022 19:13:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6D06C385A9; Wed, 27 Apr 2022 19:13:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651086811; bh=qOEGTJqEi5OzEQxCLc9HPDIXtciPfSXsM3lwZ4YNNbM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IcZfvWHNSfSiNPx82aZRh5+4QTAbfHOHngyAEz/X6I53Qt8wvYtlsP21m8bxjUFoQ 6M7XKvjqDVAoCd3KUwRqGLJEqNVrjrErYWluMcaOKYEAJUiMAdEf+sNeIACzeZmFja Tt18gX72bUOmdy3URBW0YHg8k0eGCw+VawzDSP8pKTHf/s9QE5zIssrxByLYyY5JBB 9bQXnRdTwvBMyXXicMtr5lM4IJGg8Ml2QeGlDWXCu7jpGVLKRDkg39GlIP++1elYdE jiS6cW95ReIpf4niQRaiyZto58ejdPhCFaCNwWvd1jxMIr9H/VZuU8ajkhjTl1PcmJ 5hxC3BtnuHMNw== From: Jeff Layton To: ceph-devel@vger.kernel.org Cc: xiubli@redhat.com, lhenriques@suse.de, idryomov@gmail.com Subject: [PATCH v14 20/64] ceph: add base64 endcoding routines for encrypted names Date: Wed, 27 Apr 2022 15:12:30 -0400 Message-Id: <20220427191314.222867-21-jlayton@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220427191314.222867-1-jlayton@kernel.org> References: <20220427191314.222867-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org From: Luís Henriques 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 '_'. Reviewed-by: Xiubo Li Signed-off-by: Luís Henriques Signed-off-by: Jeff Layton --- 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 1c34b8ed1266..fffbd47d9e43 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 #include #include @@ -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: '__'.) + * + * 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);