| /* |
| * Copyright (c) 2015-2018, 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). |
| * |
| * This driver is responsible for overall management of various |
| * Per File Encryption variants that work on top of or as part of different |
| * file systems. |
| * |
| * The driver has the following purpose : |
| * 1) Define priorities between PFE's if more than one is enabled |
| * 2) Extract key information from inode |
| * 3) Load and manage various keys in ICE HW engine |
| * 4) It should be invoked from various layers in FS/BLOCK/STORAGE DRIVER |
| * that need to take decision on HW encryption management of the data |
| * Some examples: |
| * BLOCK LAYER: when it takes decision on whether 2 chunks can be united |
| * to one encryption / decryption request sent to the HW |
| * |
| * UFS DRIVER: when it need to configure ICE HW with a particular key slot |
| * to be used for encryption / decryption |
| * |
| * PFE variants can differ on particular way of storing the cryptographic info |
| * inside inode, actions to be taken upon file operations, etc., but the common |
| * properties are described above |
| * |
| */ |
| |
| |
| /* Uncomment the line below to enable debug messages */ |
| /* #define DEBUG 1 */ |
| #define pr_fmt(fmt) "pfk [%s]: " fmt, __func__ |
| |
| #include <linux/module.h> |
| #include <linux/fs.h> |
| #include <linux/errno.h> |
| #include <linux/printk.h> |
| #include <linux/bio.h> |
| #include <linux/security.h> |
| #include <crypto/algapi.h> |
| #include <crypto/ice.h> |
| |
| #include <linux/pfk.h> |
| |
| #include "pfk_kc.h" |
| #include "objsec.h" |
| #include "pfk_ice.h" |
| #include "pfk_ext4.h" |
| #include "pfk_f2fs.h" |
| #include "pfk_internal.h" |
| |
| static bool pfk_ready; |
| |
| |
| /* might be replaced by a table when more than one cipher is supported */ |
| #define PFK_SUPPORTED_KEY_SIZE 32 |
| #define PFK_SUPPORTED_SALT_SIZE 32 |
| |
| /* Various PFE types and function tables to support each one of them */ |
| enum pfe_type {EXT4_CRYPT_PFE, F2FS_CRYPT_PFE, INVALID_PFE}; |
| |
| typedef int (*pfk_parse_inode_type)(const struct bio *bio, |
| const struct inode *inode, |
| struct pfk_key_info *key_info, |
| enum ice_cryto_algo_mode *algo, |
| bool *is_pfe); |
| |
| typedef bool (*pfk_allow_merge_bio_type)(const struct bio *bio1, |
| const struct bio *bio2, const struct inode *inode1, |
| const struct inode *inode2, unsigned int sectors); |
| |
| static const pfk_parse_inode_type pfk_parse_inode_ftable[] = { |
| /* EXT4_CRYPT_PFE */ &pfk_ext4_parse_inode, |
| /* F2FS_CRYPT_PFE */ &pfk_f2fs_parse_inode, |
| }; |
| |
| static const pfk_allow_merge_bio_type pfk_allow_merge_bio_ftable[] = { |
| /* EXT4_CRYPT_PFE */ &pfk_ext4_allow_merge_bio, |
| /* F2FS_CRYPT_PFE */ &pfk_f2fs_allow_merge_bio, |
| }; |
| |
| static void __exit pfk_exit(void) |
| { |
| pfk_ready = false; |
| pfk_ext4_deinit(); |
| pfk_f2fs_deinit(); |
| pfk_kc_deinit(); |
| } |
| |
| static int __init pfk_init(void) |
| { |
| |
| int ret = 0; |
| |
| ret = pfk_ext4_init(); |
| if (ret != 0) |
| goto fail; |
| |
| ret = pfk_f2fs_init(); |
| if (ret != 0) |
| goto fail; |
| |
| ret = pfk_kc_init(); |
| if (ret != 0) { |
| pr_err("could init pfk key cache, error %d\n", ret); |
| pfk_ext4_deinit(); |
| pfk_f2fs_deinit(); |
| goto fail; |
| } |
| |
| pfk_ready = true; |
| pr_info("Driver initialized successfully\n"); |
| |
| return 0; |
| |
| fail: |
| pr_err("Failed to init driver\n"); |
| return -ENODEV; |
| } |
| |
| /* |
| * If more than one type is supported simultaneously, this function will also |
| * set the priority between them |
| */ |
| static enum pfe_type pfk_get_pfe_type(const struct inode *inode) |
| { |
| if (!inode) |
| return INVALID_PFE; |
| |
| if (pfk_is_ext4_type(inode)) |
| return EXT4_CRYPT_PFE; |
| |
| if (pfk_is_f2fs_type(inode)) |
| return F2FS_CRYPT_PFE; |
| |
| return INVALID_PFE; |
| } |
| |
| /** |
| * inode_to_filename() - get the filename from inode pointer. |
| * @inode: inode pointer |
| * |
| * it is used for debug prints. |
| * |
| * Return: filename string or "unknown". |
| */ |
| char *inode_to_filename(const struct inode *inode) |
| { |
| struct dentry *dentry = NULL; |
| char *filename = NULL; |
| |
| if (!inode) |
| return "NULL"; |
| |
| if (hlist_empty(&inode->i_dentry)) |
| return "unknown"; |
| |
| dentry = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias); |
| filename = dentry->d_iname; |
| |
| return filename; |
| } |
| |
| /** |
| * pfk_is_ready() - driver is initialized and ready. |
| * |
| * Return: true if the driver is ready. |
| */ |
| static inline bool pfk_is_ready(void) |
| { |
| return pfk_ready; |
| } |
| |
| /** |
| * pfk_bio_get_inode() - get the inode from a bio. |
| * @bio: Pointer to BIO structure. |
| * |
| * Walk the bio struct links to get the inode. |
| * Please note, that in general bio may consist of several pages from |
| * several files, but in our case we always assume that all pages come |
| * from the same file, since our logic ensures it. That is why we only |
| * walk through the first page to look for inode. |
| * |
| * Return: pointer to the inode struct if successful, or NULL otherwise. |
| * |
| */ |
| static struct inode *pfk_bio_get_inode(const struct bio *bio) |
| { |
| struct inode *inode; |
| |
| if (!bio) |
| return NULL; |
| if (!bio_has_data((struct bio *)bio)) |
| return NULL; |
| if (!bio->bi_io_vec) |
| return NULL; |
| if (!bio->bi_io_vec->bv_page) |
| return NULL; |
| |
| /* Using direct-io (O_DIRECT) without page cache */ |
| inode = dio_bio_get_inode((struct bio *)bio); |
| if (inode) { |
| pr_debug("inode on direct-io, inode = 0x%pK.\n", inode); |
| return inode; |
| } |
| |
| if (!page_mapping(bio->bi_io_vec->bv_page)) |
| return NULL; |
| |
| return page_mapping(bio->bi_io_vec->bv_page)->host; |
| } |
| |
| /** |
| * pfk_key_size_to_key_type() - translate key size to key size enum |
| * @key_size: key size in bytes |
| * @key_size_type: pointer to store the output enum (can be null) |
| * |
| * return 0 in case of success, error otherwise (i.e not supported key size) |
| */ |
| int pfk_key_size_to_key_type(size_t key_size, |
| enum ice_crpto_key_size *key_size_type) |
| { |
| /* |
| * currently only 32 bit key size is supported |
| * in the future, table with supported key sizes might |
| * be introduced |
| */ |
| if (key_size != PFK_SUPPORTED_KEY_SIZE) { |
| pr_err("not supported key size %zu\n", key_size); |
| return -EINVAL; |
| } |
| |
| if (key_size_type) |
| *key_size_type = ICE_CRYPTO_KEY_SIZE_256; |
| |
| return 0; |
| } |
| |
| /* |
| * Retrieves filesystem type from inode's superblock |
| */ |
| bool pfe_is_inode_filesystem_type(const struct inode *inode, |
| const char *fs_type) |
| { |
| if (!inode || !fs_type) |
| return false; |
| |
| if (!inode->i_sb) |
| return false; |
| |
| if (!inode->i_sb->s_type) |
| return false; |
| |
| return (strcmp(inode->i_sb->s_type->name, fs_type) == 0); |
| } |
| |
| /** |
| * pfk_get_key_for_bio() - get the encryption key to be used for a bio |
| * |
| * @bio: pointer to the BIO |
| * @key_info: pointer to the key information which will be filled in |
| * @algo_mode: optional pointer to the algorithm identifier which will be set |
| * @is_pfe: will be set to false if the BIO should be left unencrypted |
| * |
| * Return: 0 if a key is being used, otherwise a -errno value |
| */ |
| static int pfk_get_key_for_bio(const struct bio *bio, |
| struct pfk_key_info *key_info, |
| enum ice_cryto_algo_mode *algo_mode, |
| bool *is_pfe, unsigned int *data_unit) |
| { |
| const struct inode *inode; |
| enum pfe_type which_pfe; |
| const struct blk_encryption_key *key = NULL; |
| char *s_type = NULL; |
| |
| inode = pfk_bio_get_inode(bio); |
| which_pfe = pfk_get_pfe_type(inode); |
| s_type = (char *)pfk_kc_get_storage_type(); |
| |
| /* |
| * Update dun based on storage type. |
| * 512 byte dun - For ext4 emmc |
| * 4K dun - For ext4 ufs, f2fs ufs and f2fs emmc |
| */ |
| |
| if (data_unit) { |
| if (!bio_dun(bio) && !memcmp(s_type, "sdcc", strlen("sdcc"))) |
| *data_unit = 1 << ICE_CRYPTO_DATA_UNIT_512_B; |
| else |
| *data_unit = 1 << ICE_CRYPTO_DATA_UNIT_4_KB; |
| } |
| |
| if (which_pfe != INVALID_PFE) { |
| /* Encrypted file; override ->bi_crypt_key */ |
| pr_debug("parsing inode %lu with PFE type %d\n", |
| inode->i_ino, which_pfe); |
| return (*(pfk_parse_inode_ftable[which_pfe])) |
| (bio, inode, key_info, algo_mode, is_pfe); |
| } |
| |
| /* |
| * bio is not for an encrypted file. Use ->bi_crypt_key if it was set. |
| * Otherwise, don't encrypt/decrypt the bio. |
| */ |
| #ifdef CONFIG_DM_DEFAULT_KEY |
| key = bio->bi_crypt_key; |
| #endif |
| if (!key) { |
| *is_pfe = false; |
| return -EINVAL; |
| } |
| |
| /* Note: the "salt" is really just the second half of the XTS key. */ |
| BUILD_BUG_ON(sizeof(key->raw) != |
| PFK_SUPPORTED_KEY_SIZE + PFK_SUPPORTED_SALT_SIZE); |
| key_info->key = &key->raw[0]; |
| key_info->key_size = PFK_SUPPORTED_KEY_SIZE; |
| key_info->salt = &key->raw[PFK_SUPPORTED_KEY_SIZE]; |
| key_info->salt_size = PFK_SUPPORTED_SALT_SIZE; |
| if (algo_mode) |
| *algo_mode = ICE_CRYPTO_ALGO_MODE_AES_XTS; |
| return 0; |
| } |
| |
| /** |
| * pfk_load_key_start() - loads PFE encryption key to the ICE |
| * Can also be invoked from non |
| * PFE context, in this case it |
| * is not relevant and is_pfe |
| * flag is set to false |
| * |
| * @bio: Pointer to the BIO structure |
| * @ice_setting: Pointer to ice setting structure that will be filled with |
| * ice configuration values, including the index to which the key was loaded |
| * @is_pfe: will be false if inode is not relevant to PFE, in such a case |
| * it should be treated as non PFE by the block layer |
| * |
| * Returns the index where the key is stored in encryption hw and additional |
| * information that will be used later for configuration of the encryption hw. |
| * |
| * Must be followed by pfk_load_key_end when key is no longer used by ice |
| * |
| */ |
| int pfk_load_key_start(const struct bio *bio, |
| struct ice_crypto_setting *ice_setting, bool *is_pfe, |
| bool async) |
| { |
| int ret = 0; |
| struct pfk_key_info key_info = {NULL, NULL, 0, 0}; |
| enum ice_cryto_algo_mode algo_mode = ICE_CRYPTO_ALGO_MODE_AES_XTS; |
| enum ice_crpto_key_size key_size_type = 0; |
| unsigned int data_unit = 1 << ICE_CRYPTO_DATA_UNIT_512_B; |
| u32 key_index = 0; |
| |
| if (!is_pfe) { |
| pr_err("is_pfe is NULL\n"); |
| 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_is_ready()) |
| return -ENODEV; |
| |
| if (!ice_setting) { |
| pr_err("ice setting is NULL\n"); |
| return -EINVAL; |
| } |
| |
| ret = pfk_get_key_for_bio(bio, &key_info, &algo_mode, is_pfe, |
| &data_unit); |
| |
| if (ret != 0) |
| return ret; |
| |
| ret = pfk_key_size_to_key_type(key_info.key_size, &key_size_type); |
| if (ret != 0) |
| return ret; |
| |
| ret = pfk_kc_load_key_start(key_info.key, key_info.key_size, |
| key_info.salt, key_info.salt_size, &key_index, async, |
| data_unit); |
| if (ret) { |
| if (ret != -EBUSY && ret != -EAGAIN) |
| pr_err("start: could not load key into pfk key cache, error %d\n", |
| ret); |
| |
| return ret; |
| } |
| |
| ice_setting->key_size = key_size_type; |
| ice_setting->algo_mode = algo_mode; |
| /* hardcoded for now */ |
| ice_setting->key_mode = ICE_CRYPTO_USE_LUT_SW_KEY; |
| ice_setting->key_index = key_index; |
| |
| pr_debug("loaded key for file %s key_index %d\n", |
| inode_to_filename(pfk_bio_get_inode(bio)), key_index); |
| |
| return 0; |
| } |
| |
| /** |
| * pfk_load_key_end() - marks the PFE key as no longer used by ICE |
| * Can also be invoked from non |
| * PFE context, in this case it is not |
| * relevant and is_pfe flag is |
| * set to false |
| * |
| * @bio: Pointer to the BIO structure |
| * @is_pfe: Pointer to is_pfe flag, which will be true if function was invoked |
| * from PFE context |
| */ |
| int pfk_load_key_end(const struct bio *bio, bool *is_pfe) |
| { |
| int ret = 0; |
| struct pfk_key_info key_info = {NULL, NULL, 0, 0}; |
| |
| if (!is_pfe) { |
| pr_err("is_pfe is NULL\n"); |
| 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_is_ready()) |
| return -ENODEV; |
| |
| ret = pfk_get_key_for_bio(bio, &key_info, NULL, is_pfe, NULL); |
| if (ret != 0) |
| return ret; |
| |
| pfk_kc_load_key_end(key_info.key, key_info.key_size, |
| key_info.salt, key_info.salt_size); |
| |
| pr_debug("finished using key for file %s\n", |
| inode_to_filename(pfk_bio_get_inode(bio))); |
| |
| return 0; |
| } |
| |
| /** |
| * pfk_allow_merge_bio() - Check if 2 BIOs can be merged. |
| * @bio1: Pointer to first BIO structure. |
| * @bio2: Pointer to second BIO structure. |
| * |
| * Prevent merging of BIOs from encrypted and non-encrypted |
| * files, or files encrypted with different key. |
| * Also prevent non encrypted and encrypted data from the same file |
| * to be merged (ecryptfs header if stored inside file should be non |
| * encrypted) |
| * This API is called by the file system block layer. |
| * |
| * Return: true if the BIOs allowed to be merged, false |
| * otherwise. |
| */ |
| bool pfk_allow_merge_bio(const struct bio *bio1, const struct bio *bio2, |
| unsigned int sectors) |
| { |
| const struct blk_encryption_key *key1 = NULL; |
| const struct blk_encryption_key *key2 = NULL; |
| const struct inode *inode1; |
| const struct inode *inode2; |
| enum pfe_type which_pfe1; |
| enum pfe_type which_pfe2; |
| |
| #ifdef CONFIG_DM_DEFAULT_KEY |
| key1 = bio1->bi_crypt_key; |
| key2 = bio2->bi_crypt_key; |
| #endif |
| |
| if (!pfk_is_ready()) |
| return false; |
| |
| if (!bio1 || !bio2) |
| return false; |
| |
| if (bio1 == bio2) |
| return true; |
| |
| inode1 = pfk_bio_get_inode(bio1); |
| inode2 = pfk_bio_get_inode(bio2); |
| |
| which_pfe1 = pfk_get_pfe_type(inode1); |
| which_pfe2 = pfk_get_pfe_type(inode2); |
| |
| /* |
| * If one bio is for an encrypted file and the other is for a different |
| * type of encrypted file or for blocks that are not part of an |
| * encrypted file, do not merge. |
| */ |
| if (which_pfe1 != which_pfe2) |
| return false; |
| |
| if (which_pfe1 != INVALID_PFE) { |
| /* Both bios are for the same type of encrypted file. */ |
| return (*(pfk_allow_merge_bio_ftable[which_pfe1]))(bio1, bio2, |
| inode1, inode2, sectors); |
| } |
| |
| /* |
| * Neither bio is for an encrypted file. Merge only if the default keys |
| * are the same (or both are NULL). |
| */ |
| return key1 == key2 || |
| (key1 && key2 && |
| !crypto_memneq(key1->raw, key2->raw, sizeof(key1->raw))); |
| } |
| |
| int pfk_fbe_clear_key(const unsigned char *key, size_t key_size, |
| const unsigned char *salt, size_t salt_size) |
| { |
| int ret = -EINVAL; |
| |
| if (!key || !salt) |
| return ret; |
| |
| ret = pfk_kc_remove_key_with_salt(key, key_size, salt, salt_size); |
| if (ret) |
| pr_err("Clear key error: ret value %d\n", ret); |
| return ret; |
| } |
| |
| /** |
| * Flush key table on storage core reset. During core reset key configuration |
| * is lost in ICE. We need to flash the cache, so that the keys will be |
| * reconfigured again for every subsequent transaction |
| */ |
| void pfk_clear_on_reset(void) |
| { |
| if (!pfk_is_ready()) |
| return; |
| |
| pfk_kc_clear_on_reset(); |
| } |
| |
| module_init(pfk_init); |
| module_exit(pfk_exit); |
| |
| MODULE_LICENSE("GPL v2"); |
| MODULE_DESCRIPTION("Per-File-Key driver"); |