From patchwork Sun Jul 9 18:53:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 13306024 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 72416C00528 for ; Sun, 9 Jul 2023 18:54:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230091AbjGISyL (ORCPT ); Sun, 9 Jul 2023 14:54:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229939AbjGISyK (ORCPT ); Sun, 9 Jul 2023 14:54:10 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD74B10C; Sun, 9 Jul 2023 11:54:09 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 6A65180CFF; Sun, 9 Jul 2023 14:54:09 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1688928849; bh=GW4ngYURvIPLue0E70Ze2qtJ6VEtxaHqCoCM6mkfVrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vRDriYTLbdZWm/QE0ALXVAPEOF7VS37u5YwRqyBukPUWnKk9A7QkRlVxotRE+QkUG 5XOHNmrPBiyRVs1qazDtzl3Jh5egTXeZQsHprBhZlACMOy6aDrL3e1zafqyDklnRUh Dpz5e0DgfBfQIRo/dYS9O9WWLvx+KnyfK6bUe/mTYgFDLKoZv2xIBwZQ/SzqBq08Vp zIokFtLsQ0NaKtYPv+wDT1qLijkSeMfJS/FSrASfuEfVI0PGzHMP1xWeETBI3zP94c TlsA82IzPMvTY5qnd0JzxynSEdRqBTaeEWUvNgTnQG/PsggMFhO2w6wGU6rDT3Snbm 45tnnpLfQereQ== From: Sweet Tea Dorminy To: "Theodore Y. Ts'o" , Jaegeuk Kim , Eric Biggers , Chris Mason , Josef Bacik , David Sterba , linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@meta.com Cc: Sweet Tea Dorminy Subject: [PATCH v2 12/14] fscrypt: allow load/save of extent contexts Date: Sun, 9 Jul 2023 14:53:45 -0400 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org The other half of using per-extent infos is saving and loading them from disk. Signed-off-by: Sweet Tea Dorminy --- fs/crypto/keysetup.c | 50 ++++++++++++++++++++++++++++++++++++++++- fs/crypto/policy.c | 20 +++++++++++++++++ include/linux/fscrypt.h | 17 ++++++++++++++ 3 files changed, 86 insertions(+), 1 deletion(-) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index c8cdcd4fe835..3b80e7061039 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -847,7 +847,6 @@ int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported) IS_CASEFOLDED(inode) && S_ISDIR(inode->i_mode), NULL); - if (res == -ENOPKG && allow_unsupported) /* Algorithm unavailable? */ res = 0; if (res == -ENOKEY) @@ -971,6 +970,55 @@ void fscrypt_free_extent_info(struct fscrypt_info **info_ptr) } EXPORT_SYMBOL_GPL(fscrypt_free_extent_info); +/** + * fscrypt_load_extent_info() - set up a preexisting extent's fscrypt_info + * @inode: the inode to which the extent belongs. Must be encrypted. + * @buf: a buffer containing the extent's stored context + * @len: the length of the @ctx buffer + * @info_ptr: a pointer to return the extent's fscrypt_info into. Should be + * a pointer to a member of the extent struct, as it will be passed + * back to the filesystem if key removal demands removal of the + * info from the extent + * + * This is not %GFP_NOFS safe, so the caller is expected to call + * memalloc_nofs_save/restore() if appropriate. + * + * Return: 0 if successful, or -errno if it fails. + */ +int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, + struct fscrypt_info **info_ptr) +{ + int res; + union fscrypt_context ctx; + union fscrypt_policy policy; + + if (!fscrypt_has_encryption_key(inode)) + return -EINVAL; + + memcpy(&ctx, buf, len); + + res = fscrypt_policy_from_context(&policy, &ctx, len); + if (res) { + fscrypt_warn(inode, + "Unrecognized or corrupt encryption context"); + return res; + } + + if (!fscrypt_supported_policy(&policy, inode)) + return -EINVAL; + + res = fscrypt_setup_encryption_info(inode, &policy, + fscrypt_context_nonce(&ctx), + IS_CASEFOLDED(inode) && + S_ISDIR(inode->i_mode), + info_ptr); + + if (res == -ENOPKG) /* Algorithm unavailable? */ + res = 0; + return res; +} +EXPORT_SYMBOL_GPL(fscrypt_load_extent_info); + /** * fscrypt_put_encryption_info() - free most of an inode's fscrypt data * @inode: an inode being evicted diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index f4456ecb3f87..9ecb01e49d33 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -762,6 +762,26 @@ int fscrypt_set_context(struct inode *inode, void *fs_data) } EXPORT_SYMBOL_GPL(fscrypt_set_context); +/** + * fscrypt_set_extent_context() - Set the fscrypt context for an extent + * @ci: info from which to fetch policy and nonce + * @ctx: where context should be written + * @len: the size of ctx + * + * Given an fscrypt_info belonging to an extent (generated via + * fscrypt_prepare_new_extent()), generate a new context and write it to @ctx. + * len is checked to be at least FSCRYPT_SET_CONTEXT_MAX_SIZE bytes. + * + * Return: size of the resulting context or a negative error code. + */ +int fscrypt_set_extent_context(struct fscrypt_info *ci, void *ctx, size_t len) +{ + if (len < FSCRYPT_SET_CONTEXT_MAX_SIZE) + return -EINVAL; + return fscrypt_new_context(ctx, &ci->ci_policy, ci->ci_nonce); +} +EXPORT_SYMBOL_GPL(fscrypt_set_extent_context); + /** * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option * @param: the mount option diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index e39165fbed41..4ba624beea91 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -325,6 +325,8 @@ int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); int fscrypt_context_for_new_inode(void *ctx, struct inode *inode); int fscrypt_set_context(struct inode *inode, void *fs_data); +int fscrypt_set_extent_context(struct fscrypt_info *info, void *ctx, + size_t len); struct fscrypt_dummy_policy { const union fscrypt_policy *policy; @@ -365,6 +367,8 @@ int fscrypt_drop_inode(struct inode *inode); int fscrypt_prepare_new_extent(struct inode *inode, struct fscrypt_info **info_ptr); void fscrypt_free_extent_info(struct fscrypt_info **info_ptr); +int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, + struct fscrypt_info **info_ptr); /* fname.c */ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, @@ -541,6 +545,12 @@ static inline int fscrypt_set_context(struct inode *inode, void *fs_data) return -EOPNOTSUPP; } +static inline int fscrypt_set_extent_context(struct fscrypt_info *info, + void *ctx, size_t len) +{ + return -EOPNOTSUPP; +} + struct fscrypt_dummy_policy { }; @@ -639,6 +649,13 @@ static inline void fscrypt_free_extent_info(struct fscrypt_info **info_ptr) { } +static inline int fscrypt_load_extent_info(struct inode *inode, void *buf, + size_t len, + struct fscrypt_info **info_ptr) +{ + return -EOPNOTSUPP; +} + /* fname.c */ static inline int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,