From patchwork Tue Jun 13 05:23:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Xiubo Li X-Patchwork-Id: 692623 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 26EB3C7EE2E for ; Tue, 13 Jun 2023 05:29:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237312AbjFMF3y (ORCPT ); Tue, 13 Jun 2023 01:29:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240155AbjFMF3V (ORCPT ); Tue, 13 Jun 2023 01:29:21 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D81C19C for ; Mon, 12 Jun 2023 22:28:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686634086; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fyaaPgYGwAJb95hHTyeWVNR81aQLNtkgKza5n1NsFcs=; b=d3RBcipWoVrgi3YUfgEfU3lGZwqKp6Bnff6v2/DHLw2+cfF3dUxVykJ8k/ec2yLnIKhsMF usthzUtaxVohtvB94kPhZeh9kaOo5+zpVnyxXDV0KJOHvo9jbyvmD2S7Q9sSVWjcFs1VaG WXhKIA+T2sx44WFvWpMKTdRrILkmSz8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-137-wDUguIJ0M7Co_3ZsDa4_3Q-1; Tue, 13 Jun 2023 01:28:03 -0400 X-MC-Unique: wDUguIJ0M7Co_3ZsDa4_3Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 559991C02D24; Tue, 13 Jun 2023 05:28:03 +0000 (UTC) Received: from li-a71a4dcc-35d1-11b2-a85c-951838863c8d.ibm.com.com (ovpn-12-155.pek2.redhat.com [10.72.12.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30A951121314; Tue, 13 Jun 2023 05:27:59 +0000 (UTC) From: xiubli@redhat.com To: idryomov@gmail.com, ceph-devel@vger.kernel.org Cc: jlayton@kernel.org, vshankar@redhat.com, mchangir@redhat.com, lhenriques@suse.de, Xiubo Li Subject: [PATCH v20 19/71] ceph: add base64 endcoding routines for encrypted names Date: Tue, 13 Jun 2023 13:23:32 +0800 Message-Id: <20230613052424.254540-20-xiubli@redhat.com> In-Reply-To: <20230613052424.254540-1-xiubli@redhat.com> References: <20230613052424.254540-1-xiubli@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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 '_'. Tested-by: Luís Henriques Tested-by: Venky Shankar Signed-off-by: Luís Henriques Reviewed-by: Xiubo Li 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 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 #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);