From patchwork Tue Jan 11 19:15:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 12710406 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 72C5EC433EF for ; Tue, 11 Jan 2022 19:16:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350435AbiAKTQP (ORCPT ); Tue, 11 Jan 2022 14:16:15 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:36074 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346070AbiAKTQO (ORCPT ); Tue, 11 Jan 2022 14:16:14 -0500 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 AB34961781; Tue, 11 Jan 2022 19:16:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6E47C36AE9; Tue, 11 Jan 2022 19:16:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641928573; bh=6x0OJ1T2M4Aq5qaTrx3AT15x7MQ7bwyNPgvLZjT0jOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AJt2ENw8vJfA+WRn0wc+MebIjHlSi61FfJ+FN5Wd6Tu0id8KHFmFpFEJFxMdtXeBw H8nHyqV7xeVTbQ45Zb39SfcHBvEiTniWcQ/eNy4lsyb/iAKiXtUhFs/vDFfvawaPgk S0xGcLnBH3BNaicvYj03EEoDA2A14rdx1YB988QNkkApfIR4o1ZCAx7MZgIXXRl3is q9tUACwtdabv5Aao4jw71j1yD5dByEqkD7TM92sN/7TXSMx5vYBmHKADcuFxAkkI+x H+irCEIA5w5pL5AjBjSSAjEFvgU6RUiYGj4HCplpr0e4hfsLWti5JBvvaetmJSnOhx ev2EYL+ynE+WA== From: Jeff Layton To: ceph-devel@vger.kernel.org, linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, idryomov@gmail.com Subject: [RFC PATCH v10 03/48] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Date: Tue, 11 Jan 2022 14:15:23 -0500 Message-Id: <20220111191608.88762-4-jlayton@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220111191608.88762-1-jlayton@kernel.org> References: <20220111191608.88762-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org For ceph, we want to use our own scheme for handling filenames that are are longer than NAME_MAX after encryption and Base64 encoding. This allows us to have a consistent view of the encrypted filenames for clients that don't support fscrypt and clients that do but that don't have the key. Currently, fs/crypto only supports encrypting filenames using fscrypt_setup_filename, but that also handles encoding nokey names. Ceph can't use that because it handles nokey names in a different way. Export fscrypt_fname_encrypt. Rename fscrypt_fname_encrypted_size to __fscrypt_fname_encrypted_size and add a new wrapper called fscrypt_fname_encrypted_size that takes an inode argument rather than a pointer to a fscrypt_policy union. Signed-off-by: Jeff Layton Acked-by: Eric Biggers --- fs/crypto/fname.c | 36 ++++++++++++++++++++++++++++++------ fs/crypto/fscrypt_private.h | 9 +++------ fs/crypto/hooks.c | 6 +++--- include/linux/fscrypt.h | 4 ++++ 4 files changed, 40 insertions(+), 15 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 1e4233c95005..733ae43da6ec 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -79,7 +79,8 @@ static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) /** * fscrypt_fname_encrypt() - encrypt a filename * @inode: inode of the parent directory (for regular filenames) - * or of the symlink (for symlink targets) + * or of the symlink (for symlink targets). Key must already be + * set up. * @iname: the filename to encrypt * @out: (output) the encrypted filename * @olen: size of the encrypted filename. It must be at least @iname->len. @@ -130,6 +131,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, return 0; } +EXPORT_SYMBOL_GPL(fscrypt_fname_encrypt); /** * fname_decrypt() - decrypt a filename @@ -257,9 +259,9 @@ int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst) } EXPORT_SYMBOL_GPL(fscrypt_base64url_decode); -bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, - u32 orig_len, u32 max_len, - u32 *encrypted_len_ret) +bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, + u32 orig_len, u32 max_len, + u32 *encrypted_len_ret) { int padding = 4 << (fscrypt_policy_flags(policy) & FSCRYPT_POLICY_FLAGS_PAD_MASK); @@ -273,6 +275,29 @@ bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, return true; } +/** + * fscrypt_fname_encrypted_size() - calculate length of encrypted filename + * @inode: parent inode of dentry name being encrypted. Key must + * already be set up. + * @orig_len: length of the original filename + * @max_len: maximum length to return + * @encrypted_len_ret: where calculated length should be returned (on success) + * + * Filenames that are shorter than the maximum length may have their lengths + * increased slightly by encryption, due to padding that is applied. + * + * Return: false if the orig_len is greater than max_len. Otherwise, true and + * fill out encrypted_len_ret with the length (up to max_len). + */ +bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, + u32 max_len, u32 *encrypted_len_ret) +{ + return __fscrypt_fname_encrypted_size(&inode->i_crypt_info->ci_policy, + orig_len, max_len, + encrypted_len_ret); +} +EXPORT_SYMBOL_GPL(fscrypt_fname_encrypted_size); + /** * fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames * @max_encrypted_len: maximum length of encrypted filenames the buffer will be @@ -428,8 +453,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, return ret; if (fscrypt_has_encryption_key(dir)) { - if (!fscrypt_fname_encrypted_size(&dir->i_crypt_info->ci_policy, - iname->len, NAME_MAX, + if (!fscrypt_fname_encrypted_size(dir, iname->len, NAME_MAX, &fname->crypto_buf.len)) return -ENAMETOOLONG; fname->crypto_buf.name = kmalloc(fname->crypto_buf.len, diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 5b0a9e6478b5..f3e6e566daff 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -297,14 +297,11 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, const struct fscrypt_info *ci); /* fname.c */ -int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, - u8 *out, unsigned int olen); -bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, - u32 orig_len, u32 max_len, - u32 *encrypted_len_ret); +bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, + u32 orig_len, u32 max_len, + u32 *encrypted_len_ret); /* hkdf.c */ - struct fscrypt_hkdf { struct crypto_shash *hmac_tfm; }; diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index af74599ae1cf..7c01025879b3 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -228,9 +228,9 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target, * counting it (even though it is meaningless for ciphertext) is simpler * for now since filesystems will assume it is there and subtract it. */ - if (!fscrypt_fname_encrypted_size(policy, len, - max_len - sizeof(struct fscrypt_symlink_data), - &disk_link->len)) + if (!__fscrypt_fname_encrypted_size(policy, len, + max_len - sizeof(struct fscrypt_symlink_data), + &disk_link->len)) return -ENAMETOOLONG; disk_link->len += sizeof(struct fscrypt_symlink_data); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 671181d196a8..c90e176b5843 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -308,8 +308,12 @@ void fscrypt_free_inode(struct inode *inode); int fscrypt_drop_inode(struct inode *inode); /* fname.c */ +int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, + u8 *out, unsigned int olen); int fscrypt_base64url_encode(const u8 *src, int len, char *dst); int fscrypt_base64url_decode(const char *src, int len, u8 *dst); +bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, + u32 max_len, u32 *encrypted_len_ret); int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname, int lookup, struct fscrypt_name *fname);