From patchwork Fri Jun 25 13:58:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 12345145 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59DC2C49EAF for ; Fri, 25 Jun 2021 13:58:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36DA16198A for ; Fri, 25 Jun 2021 13:58:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231502AbhFYOA6 (ORCPT ); Fri, 25 Jun 2021 10:00:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:32812 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231215AbhFYOA5 (ORCPT ); Fri, 25 Jun 2021 10:00:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BA5B56197C; Fri, 25 Jun 2021 13:58:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624629517; bh=9ZV+dp80mshXypGX/qNEFhBN7oqDNHcc+7LrhuPBANE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nssjp0Kry9pdTXU6VrXmcVrK4XxTOzKb5r3ozFUt9Jl0x2rWqT71gS4g3KLXdTCzK K7xxeX0OGgGunz34sgTksoFgWAmqreBpJOPIIXecdaLzyoFKNNfwKSSyH6V98Qaelb YuW146g5i2GWiBykRRS9Mwi9HBG3cVclOx0FoWKMGMfrfxNS/PEr5mDCW0XpS7wkYK xxQaEEyCt5SmVdgP4Jemo7NFCLbqzAZ3cEilLhg6UN2l4AQn0CnqieiTJf87hNTG/P O6kkkjIBqYfxFWQ6pdP6B9ivcLSIvXn9s321TAKqJ6fRy7Zzr0FvPGbsYuGvqJU6Ap yZ1ADd41LP5Lw== From: Jeff Layton To: ceph-devel@vger.kernel.org Cc: lhenriques@suse.de, xiubli@redhat.com, linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org, dhowells@redhat.com Subject: [RFC PATCH v7 02/24] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Date: Fri, 25 Jun 2021 09:58:12 -0400 Message-Id: <20210625135834.12934-3-jlayton@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210625135834.12934-1-jlayton@kernel.org> References: <20210625135834.12934-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.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 --- fs/crypto/fname.c | 34 ++++++++++++++++++++++++---------- include/linux/fscrypt.h | 5 +++++ 2 files changed, 29 insertions(+), 10 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 6ca7d16593ff..32b1f50433ba 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -178,10 +178,8 @@ static int fname_decrypt(const struct inode *inode, static const char lookup_table[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; -#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) - /** - * base64_encode() - base64-encode some bytes + * fscrypt_base64_encode() - base64-encode some bytes * @src: the bytes to encode * @len: number of bytes to encode * @dst: (output) the base64-encoded string. Not NUL-terminated. @@ -191,7 +189,7 @@ static const char lookup_table[65] = * * Return: length of the encoded string */ -static int base64_encode(const u8 *src, int len, char *dst) +int fscrypt_base64_encode(const u8 *src, int len, char *dst) { int i, bits = 0, ac = 0; char *cp = dst; @@ -209,8 +207,20 @@ static int base64_encode(const u8 *src, int len, char *dst) *cp++ = lookup_table[ac & 0x3f]; return cp - dst; } +EXPORT_SYMBOL(fscrypt_base64_encode); -static int base64_decode(const char *src, int len, u8 *dst) +/** + * fscrypt_base64_decode() - base64-decode some bytes + * @src: the bytes to decode + * @len: number of bytes to decode + * @dst: (output) decoded binary data + * + * Decode an input string that was previously encoded using + * fscrypt_base64_encode. + * + * Return: length of the decoded binary data + */ +int fscrypt_base64_decode(const char *src, int len, u8 *dst) { int i, bits = 0, ac = 0; const char *p; @@ -232,6 +242,7 @@ static int base64_decode(const char *src, int len, u8 *dst) return -1; return cp - dst; } +EXPORT_SYMBOL(fscrypt_base64_decode); bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, u32 orig_len, u32 max_len, @@ -263,8 +274,9 @@ bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str) { - const u32 max_encoded_len = BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX); u32 max_presented_len; + const u32 max_encoded_len = + FSCRYPT_BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX); max_presented_len = max(max_encoded_len, max_encrypted_len); @@ -342,7 +354,7 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, offsetof(struct fscrypt_nokey_name, bytes)); BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, bytes) != offsetof(struct fscrypt_nokey_name, sha256)); - BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX); + BUILD_BUG_ON(FSCRYPT_BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX); if (hash) { nokey_name.dirhash[0] = hash; @@ -362,7 +374,8 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, nokey_name.sha256); size = FSCRYPT_NOKEY_NAME_MAX; } - oname->len = base64_encode((const u8 *)&nokey_name, size, oname->name); + oname->len = fscrypt_base64_encode((const u8 *)&nokey_name, size, + oname->name); return 0; } EXPORT_SYMBOL(fscrypt_fname_disk_to_usr); @@ -436,14 +449,15 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, * user-supplied name */ - if (iname->len > BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX)) + if (iname->len > FSCRYPT_BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX)) return -ENOENT; fname->crypto_buf.name = kmalloc(FSCRYPT_NOKEY_NAME_MAX, GFP_KERNEL); if (fname->crypto_buf.name == NULL) return -ENOMEM; - ret = base64_decode(iname->name, iname->len, fname->crypto_buf.name); + ret = fscrypt_base64_decode(iname->name, iname->len, + fname->crypto_buf.name); if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) || (ret > offsetof(struct fscrypt_nokey_name, sha256) && ret != FSCRYPT_NOKEY_NAME_MAX)) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 2ea1387bb497..e300f6145ddc 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 +/* Calculate worst-case base64 encoding inflation */ +#define FSCRYPT_BASE64_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_base64_encode(const u8 *src, int len, char *dst); +int fscrypt_base64_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);