/* * Copyright (c) 2015-2017, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ /* * Per-File-Key (PFK) - FSCRYPT * * This driver is used for working with F2FS crypt extension * * The key information is stored in node by F2FS when file is first opened * and will be later accessed by Block Device Driver to actually load the key * to encryption hw. * * PFK exposes API's for loading and removing keys from encryption hw * and also API to determine whether 2 adjacent blocks can be agregated by * Block Layer in one request to encryption hw. * */ /* Uncomment the line below to enable debug messages */ #define DEBUG 1 #define pr_fmt(fmt) "pfk_fscrypt [%s]: " fmt, __func__ #include #include #include #include #include "fscrypt_ice.h" #include "pfk_fscrypt.h" static bool pfk_fscrypt_ready; /* * pfk_fscrypt_deinit() - Deinit function, should be invoked by upper PFK layer */ void pfk_fscrypt_deinit(void) { pfk_fscrypt_ready = false; } /* * pfk_fscrypt_init() - Init function, should be invoked by upper PFK layer */ int __init pfk_fscrypt_init(void) { pfk_fscrypt_ready = true; pr_info("PFK FSCRYPT inited successfully\n"); return 0; } /** * pfk_fscrypt_is_ready() - driver is initialized and ready. * * Return: true if the driver is ready. */ static inline bool pfk_fscrypt_is_ready(void) { return pfk_fscrypt_ready; } /** * pfk_is_f2fs_type() - return true if inode belongs to ICE F2FS PFE * @inode: inode pointer */ bool pfk_is_fscrypt_type(const struct inode *inode) { if (!pfe_is_inode_filesystem_type(inode, "f2fs")) return false; return fscrypt_should_be_processed_by_ice(inode); } /** * pfk_fscrypt_parse_cipher() - parse cipher from inode to enum * @inode: inode * @algo: pointer to store the output enum (can be null) * * return 0 in case of success, error otherwise (i.e not supported cipher) */ static int pfk_fscrypt_parse_cipher(const struct inode *inode, enum ice_cryto_algo_mode *algo) { /* * currently only AES XTS algo is supported * in the future, table with supported ciphers might * be introduced */ if (!inode) return -EINVAL; if (!fscrypt_is_aes_xts_cipher(inode)) { pr_err("f2fs alghoritm is not supported by pfk\n"); return -EINVAL; } if (algo) *algo = ICE_CRYPTO_ALGO_MODE_AES_XTS; return 0; } int pfk_fscrypt_parse_inode(const struct bio *bio, const struct inode *inode, struct pfk_key_info *key_info, enum ice_cryto_algo_mode *algo, bool *is_pfe, const char *storage_type) { int ret = 0; if (!is_pfe) return -EINVAL; /* * only a few errors below can indicate that * this function was not invoked within PFE context, * otherwise we will consider it PFE */ *is_pfe = true; if (!pfk_fscrypt_is_ready()) return -ENODEV; if (!inode) return -EINVAL; if (!key_info) return -EINVAL; key_info->key = fscrypt_get_ice_encryption_key(inode); if (!key_info->key) { pr_err("could not parse key from f2fs\n"); return -EINVAL; } key_info->key_size = fscrypt_get_ice_encryption_key_size(inode); if (!key_info->key_size) { pr_err("could not parse key size from f2fs\n"); return -EINVAL; } key_info->salt = fscrypt_get_ice_encryption_salt(inode); if (!key_info->salt) { pr_err("could not parse salt from f2fs\n"); return -EINVAL; } key_info->salt_size = fscrypt_get_ice_encryption_salt_size(inode); if (!key_info->salt_size) { pr_err("could not parse salt size from f2fs\n"); return -EINVAL; } ret = pfk_fscrypt_parse_cipher(inode, algo); if (ret != 0) { pr_err("not supported cipher\n"); return ret; } return 0; } bool pfk_fscrypt_allow_merge_bio(const struct bio *bio1, const struct bio *bio2, const struct inode *inode1, const struct inode *inode2) { bool mergeable; /* if there is no fscrypt pfk, don't disallow merging blocks */ if (!pfk_fscrypt_is_ready()) return true; if (!inode1 || !inode2) return false; mergeable = fscrypt_is_ice_encryption_info_equal(inode1, inode2); if (!mergeable) return false; /* ICE allows only consecutive iv_key stream. */ if (!bio_dun(bio1) && !bio_dun(bio2)) return true; else if(!bio_dun(bio1) || !bio_dun(bio2)) return false; return bio_end_dun(bio1) == bio_dun(bio2); }