diff options
Diffstat (limited to 'security/pfe/pfk_ext4.c')
| -rw-r--r-- | security/pfe/pfk_ext4.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/security/pfe/pfk_ext4.c b/security/pfe/pfk_ext4.c new file mode 100644 index 000000000000..07e2c7ab829c --- /dev/null +++ b/security/pfe/pfk_ext4.c @@ -0,0 +1,212 @@ +/* + * Copyright (c) 2015-2016, 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) - EXT4 + * + * This driver is used for working with EXT4 crypt extension + * + * The key information is stored in node by EXT4 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_ext4 [%s]: " fmt, __func__ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/errno.h> +#include <linux/printk.h> + +#include "ext4_ice.h" +#include "pfk_ext4.h" + +static bool pfk_ext4_ready; + +/* + * pfk_ext4_deinit() - Deinit function, should be invoked by upper PFK layer + */ +void __exit pfk_ext4_deinit(void) +{ + pfk_ext4_ready = false; +} + +/* + * pfk_ecryptfs_init() - Init function, should be invoked by upper PFK layer + */ +int __init pfk_ext4_init(void) +{ + pfk_ext4_ready = true; + pr_info("PFK EXT4 inited successfully\n"); + + return 0; +} + +/** + * pfk_ecryptfs_is_ready() - driver is initialized and ready. + * + * Return: true if the driver is ready. + */ +static inline bool pfk_ext4_is_ready(void) +{ + return pfk_ext4_ready; +} + +/** + * pfk_ext4_dump_inode() - dumps all interesting info about inode to the screen + * + * + */ +/* + * static void pfk_ext4_dump_inode(const struct inode* inode) + * { + * struct ext4_crypt_info *ci = ext4_encryption_info((struct inode*)inode); + * + * pr_debug("dumping inode with address 0x%p\n", inode); + * pr_debug("S_ISREG is %d\n", S_ISREG(inode->i_mode)); + * pr_debug("EXT4_INODE_ENCRYPT flag is %d\n", + * ext4_test_inode_flag((struct inode*)inode, EXT4_INODE_ENCRYPT)); + * if (ci) { + * pr_debug("crypt_info address 0x%p\n", ci); + * pr_debug("ci->ci_data_mode %d\n", ci->ci_data_mode); + * } else { + * pr_debug("crypt_info is NULL\n"); + * } + * } +*/ + +/** + * pfk_is_ext4_type() - return true if inode belongs to ICE EXT4 PFE + * @inode: inode pointer + */ +bool pfk_is_ext4_type(const struct inode *inode) +{ + if (!pfe_is_inode_filesystem_type(inode, "ext4")) + return false; + + return ext4_should_be_processed_by_ice(inode); +} + +/** + * pfk_ext4_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_ext4_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 (!ext4_is_aes_xts_cipher(inode)) { + pr_err("ext4 alghoritm is not supported by pfk\n"); + return -EINVAL; + } + + if (algo) + *algo = ICE_CRYPTO_ALGO_MODE_AES_XTS; + + return 0; +} + + +int pfk_ext4_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) +{ + 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_ext4_is_ready()) + return -ENODEV; + + if (!inode) + return -EINVAL; + + if (!key_info) + return -EINVAL; + + key_info->key = ext4_get_ice_encryption_key(inode); + if (!key_info->key) { + pr_err("could not parse key from ext4\n"); + return -EINVAL; + } + + key_info->key_size = ext4_get_ice_encryption_key_size(inode); + if (!key_info->key_size) { + pr_err("could not parse key size from ext4\n"); + return -EINVAL; + } + + key_info->salt = ext4_get_ice_encryption_salt(inode); + if (!key_info->salt) { + pr_err("could not parse salt from ext4\n"); + return -EINVAL; + } + + key_info->salt_size = ext4_get_ice_encryption_salt_size(inode); + if (!key_info->salt_size) { + pr_err("could not parse salt size from ext4\n"); + return -EINVAL; + } + + ret = pfk_ext4_parse_cipher(inode, algo); + if (ret != 0) { + pr_err("not supported cipher\n"); + return ret; + } + + return 0; +} + +bool pfk_ext4_allow_merge_bio(const struct bio *bio1, + const struct bio *bio2, const struct inode *inode1, + const struct inode *inode2) +{ + /* if there is no ext4 pfk, don't disallow merging blocks */ + if (!pfk_ext4_is_ready()) + return true; + + if (!inode1 || !inode2) + return false; + + return ext4_is_ice_encryption_info_equal(inode1, inode2); +} + |