| /** |
| * eCryptfs: Linux filesystem encryption layer |
| * |
| * Copyright (C) 1997-2004 Erez Zadok |
| * Copyright (C) 2001-2004 Stony Brook University |
| * Copyright (C) 2004-2007 International Business Machines Corp. |
| * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| * Michael C. Thompson <mcthomps@us.ibm.com> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as |
| * published by the Free Software Foundation; either version 2 of the |
| * License, or (at your option) any later version. |
| * |
| * 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. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
| * 02111-1307, USA. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/mount.h> |
| #include <linux/pagemap.h> |
| #include <linux/random.h> |
| #include <linux/compiler.h> |
| #include <linux/key.h> |
| #include <linux/namei.h> |
| #include <linux/crypto.h> |
| #include <linux/file.h> |
| #include <linux/scatterlist.h> |
| #include "ecryptfs_kernel.h" |
| |
| static int |
| ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| struct page *dst_page, int dst_offset, |
| struct page *src_page, int src_offset, int size, |
| unsigned char *iv); |
| static int |
| ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| struct page *dst_page, int dst_offset, |
| struct page *src_page, int src_offset, int size, |
| unsigned char *iv); |
| |
| /** |
| * ecryptfs_to_hex |
| * @dst: Buffer to take hex character representation of contents of |
| * src; must be at least of size (src_size * 2) |
| * @src: Buffer to be converted to a hex string respresentation |
| * @src_size: number of bytes to convert |
| */ |
| void ecryptfs_to_hex(char *dst, char *src, size_t src_size) |
| { |
| int x; |
| |
| for (x = 0; x < src_size; x++) |
| sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]); |
| } |
| |
| /** |
| * ecryptfs_from_hex |
| * @dst: Buffer to take the bytes from src hex; must be at least of |
| * size (src_size / 2) |
| * @src: Buffer to be converted from a hex string respresentation to raw value |
| * @dst_size: size of dst buffer, or number of hex characters pairs to convert |
| */ |
| void ecryptfs_from_hex(char *dst, char *src, int dst_size) |
| { |
| int x; |
| char tmp[3] = { 0, }; |
| |
| for (x = 0; x < dst_size; x++) { |
| tmp[0] = src[x * 2]; |
| tmp[1] = src[x * 2 + 1]; |
| dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); |
| } |
| } |
| |
| /** |
| * ecryptfs_calculate_md5 - calculates the md5 of @src |
| * @dst: Pointer to 16 bytes of allocated memory |
| * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| * @src: Data to be md5'd |
| * @len: Length of @src |
| * |
| * Uses the allocated crypto context that crypt_stat references to |
| * generate the MD5 sum of the contents of src. |
| */ |
| static int ecryptfs_calculate_md5(char *dst, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| char *src, int len) |
| { |
| struct scatterlist sg; |
| struct hash_desc desc = { |
| .tfm = crypt_stat->hash_tfm, |
| .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| }; |
| int rc = 0; |
| |
| mutex_lock(&crypt_stat->cs_hash_tfm_mutex); |
| sg_init_one(&sg, (u8 *)src, len); |
| if (!desc.tfm) { |
| desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0, |
| CRYPTO_ALG_ASYNC); |
| if (IS_ERR(desc.tfm)) { |
| rc = PTR_ERR(desc.tfm); |
| ecryptfs_printk(KERN_ERR, "Error attempting to " |
| "allocate crypto context; rc = [%d]\n", |
| rc); |
| goto out; |
| } |
| crypt_stat->hash_tfm = desc.tfm; |
| } |
| crypto_hash_init(&desc); |
| crypto_hash_update(&desc, &sg, len); |
| crypto_hash_final(&desc, dst); |
| mutex_unlock(&crypt_stat->cs_hash_tfm_mutex); |
| out: |
| return rc; |
| } |
| |
| int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
| char *cipher_name, |
| char *chaining_modifier) |
| { |
| int cipher_name_len = strlen(cipher_name); |
| int chaining_modifier_len = strlen(chaining_modifier); |
| int algified_name_len; |
| int rc; |
| |
| algified_name_len = (chaining_modifier_len + cipher_name_len + 3); |
| (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); |
| if (!(*algified_name)) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| snprintf((*algified_name), algified_name_len, "%s(%s)", |
| chaining_modifier, cipher_name); |
| rc = 0; |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_derive_iv |
| * @iv: destination for the derived iv vale |
| * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| * @offset: Offset of the page whose's iv we are to derive |
| * |
| * Generate the initialization vector from the given root IV and page |
| * offset. |
| * |
| * Returns zero on success; non-zero on error. |
| */ |
| static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
| pgoff_t offset) |
| { |
| int rc = 0; |
| char dst[MD5_DIGEST_SIZE]; |
| char src[ECRYPTFS_MAX_IV_BYTES + 16]; |
| |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "root iv:\n"); |
| ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); |
| } |
| /* TODO: It is probably secure to just cast the least |
| * significant bits of the root IV into an unsigned long and |
| * add the offset to that rather than go through all this |
| * hashing business. -Halcrow */ |
| memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); |
| memset((src + crypt_stat->iv_bytes), 0, 16); |
| snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset); |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "source:\n"); |
| ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); |
| } |
| rc = ecryptfs_calculate_md5(dst, crypt_stat, src, |
| (crypt_stat->iv_bytes + 16)); |
| if (rc) { |
| ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| "MD5 while generating IV for a page\n"); |
| goto out; |
| } |
| memcpy(iv, dst, crypt_stat->iv_bytes); |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); |
| ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); |
| } |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_init_crypt_stat |
| * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| * |
| * Initialize the crypt_stat structure. |
| */ |
| void |
| ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| mutex_init(&crypt_stat->cs_mutex); |
| mutex_init(&crypt_stat->cs_tfm_mutex); |
| mutex_init(&crypt_stat->cs_hash_tfm_mutex); |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_STRUCT_INITIALIZED); |
| } |
| |
| /** |
| * ecryptfs_destruct_crypt_stat |
| * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| * |
| * Releases all memory associated with a crypt_stat struct. |
| */ |
| void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| if (crypt_stat->tfm) |
| crypto_free_blkcipher(crypt_stat->tfm); |
| if (crypt_stat->hash_tfm) |
| crypto_free_hash(crypt_stat->hash_tfm); |
| memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| } |
| |
| void ecryptfs_destruct_mount_crypt_stat( |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| { |
| if (mount_crypt_stat->global_auth_tok_key) |
| key_put(mount_crypt_stat->global_auth_tok_key); |
| if (mount_crypt_stat->global_key_tfm) |
| crypto_free_blkcipher(mount_crypt_stat->global_key_tfm); |
| memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
| } |
| |
| /** |
| * virt_to_scatterlist |
| * @addr: Virtual address |
| * @size: Size of data; should be an even multiple of the block size |
| * @sg: Pointer to scatterlist array; set to NULL to obtain only |
| * the number of scatterlist structs required in array |
| * @sg_size: Max array size |
| * |
| * Fills in a scatterlist array with page references for a passed |
| * virtual address. |
| * |
| * Returns the number of scatterlist structs in array used |
| */ |
| int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, |
| int sg_size) |
| { |
| int i = 0; |
| struct page *pg; |
| int offset; |
| int remainder_of_page; |
| |
| while (size > 0 && i < sg_size) { |
| pg = virt_to_page(addr); |
| offset = offset_in_page(addr); |
| if (sg) { |
| sg[i].page = pg; |
| sg[i].offset = offset; |
| } |
| remainder_of_page = PAGE_CACHE_SIZE - offset; |
| if (size >= remainder_of_page) { |
| if (sg) |
| sg[i].length = remainder_of_page; |
| addr += remainder_of_page; |
| size -= remainder_of_page; |
| } else { |
| if (sg) |
| sg[i].length = size; |
| addr += size; |
| size = 0; |
| } |
| i++; |
| } |
| if (size > 0) |
| return -ENOMEM; |
| return i; |
| } |
| |
| /** |
| * encrypt_scatterlist |
| * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| * @dest_sg: Destination of encrypted data |
| * @src_sg: Data to be encrypted |
| * @size: Length of data to be encrypted |
| * @iv: iv to use during encryption |
| * |
| * Returns the number of bytes encrypted; negative value on error |
| */ |
| static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
| struct scatterlist *dest_sg, |
| struct scatterlist *src_sg, int size, |
| unsigned char *iv) |
| { |
| struct blkcipher_desc desc = { |
| .tfm = crypt_stat->tfm, |
| .info = iv, |
| .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| }; |
| int rc = 0; |
| |
| BUG_ON(!crypt_stat || !crypt_stat->tfm |
| || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| ECRYPTFS_STRUCT_INITIALIZED)); |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n", |
| crypt_stat->key_size); |
| ecryptfs_dump_hex(crypt_stat->key, |
| crypt_stat->key_size); |
| } |
| /* Consider doing this once, when the file is opened */ |
| mutex_lock(&crypt_stat->cs_tfm_mutex); |
| rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
| crypt_stat->key_size); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", |
| rc); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| rc = -EINVAL; |
| goto out; |
| } |
| ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size); |
| crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| out: |
| return rc; |
| } |
| |
| static void |
| ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx, |
| int *byte_offset, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| unsigned long extent_num) |
| { |
| unsigned long lower_extent_num; |
| int extents_occupied_by_headers_at_front; |
| int bytes_occupied_by_headers_at_front; |
| int extent_offset; |
| int extents_per_page; |
| |
| bytes_occupied_by_headers_at_front = |
| ( crypt_stat->header_extent_size |
| * crypt_stat->num_header_extents_at_front ); |
| extents_occupied_by_headers_at_front = |
| ( bytes_occupied_by_headers_at_front |
| / crypt_stat->extent_size ); |
| lower_extent_num = extents_occupied_by_headers_at_front + extent_num; |
| extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| (*lower_page_idx) = lower_extent_num / extents_per_page; |
| extent_offset = lower_extent_num % extents_per_page; |
| (*byte_offset) = extent_offset * crypt_stat->extent_size; |
| ecryptfs_printk(KERN_DEBUG, " * crypt_stat->header_extent_size = " |
| "[%d]\n", crypt_stat->header_extent_size); |
| ecryptfs_printk(KERN_DEBUG, " * crypt_stat->" |
| "num_header_extents_at_front = [%d]\n", |
| crypt_stat->num_header_extents_at_front); |
| ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_" |
| "front = [%d]\n", extents_occupied_by_headers_at_front); |
| ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n", |
| lower_extent_num); |
| ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n", |
| extents_per_page); |
| ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n", |
| (*lower_page_idx)); |
| ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n", |
| extent_offset); |
| ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n", |
| (*byte_offset)); |
| } |
| |
| static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx, |
| struct page *lower_page, |
| struct inode *lower_inode, |
| int byte_offset_in_page, int bytes_to_write) |
| { |
| int rc = 0; |
| |
| if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { |
| rc = ecryptfs_commit_lower_page(lower_page, lower_inode, |
| ctx->param.lower_file, |
| byte_offset_in_page, |
| bytes_to_write); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error calling lower " |
| "commit; rc = [%d]\n", rc); |
| goto out; |
| } |
| } else { |
| rc = ecryptfs_writepage_and_release_lower_page(lower_page, |
| lower_inode, |
| ctx->param.wbc); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error calling lower " |
| "writepage(); rc = [%d]\n", rc); |
| goto out; |
| } |
| } |
| out: |
| return rc; |
| } |
| |
| static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx, |
| struct page **lower_page, |
| struct inode *lower_inode, |
| unsigned long lower_page_idx, |
| int byte_offset_in_page) |
| { |
| int rc = 0; |
| |
| if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { |
| /* TODO: Limit this to only the data extents that are |
| * needed */ |
| rc = ecryptfs_get_lower_page(lower_page, lower_inode, |
| ctx->param.lower_file, |
| lower_page_idx, |
| byte_offset_in_page, |
| (PAGE_CACHE_SIZE |
| - byte_offset_in_page)); |
| if (rc) { |
| ecryptfs_printk( |
| KERN_ERR, "Error attempting to grab, map, " |
| "and prepare_write lower page with index " |
| "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc); |
| goto out; |
| } |
| } else { |
| *lower_page = grab_cache_page(lower_inode->i_mapping, |
| lower_page_idx); |
| if (!(*lower_page)) { |
| rc = -EINVAL; |
| ecryptfs_printk( |
| KERN_ERR, "Error attempting to grab and map " |
| "lower page with index [0x%.16x]; rc = [%d]\n", |
| lower_page_idx, rc); |
| goto out; |
| } |
| } |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_encrypt_page |
| * @ctx: The context of the page |
| * |
| * Encrypt an eCryptfs page. This is done on a per-extent basis. Note |
| * that eCryptfs pages may straddle the lower pages -- for instance, |
| * if the file was created on a machine with an 8K page size |
| * (resulting in an 8K header), and then the file is copied onto a |
| * host with a 32K page size, then when reading page 0 of the eCryptfs |
| * file, 24K of page 0 of the lower file will be read and decrypted, |
| * and then 8K of page 1 of the lower file will be read and decrypted. |
| * |
| * The actual operations performed on each page depends on the |
| * contents of the ecryptfs_page_crypt_context struct. |
| * |
| * Returns zero on success; negative on error |
| */ |
| int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx) |
| { |
| char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
| unsigned long base_extent; |
| unsigned long extent_offset = 0; |
| unsigned long lower_page_idx = 0; |
| unsigned long prior_lower_page_idx = 0; |
| struct page *lower_page; |
| struct inode *lower_inode; |
| struct ecryptfs_inode_info *inode_info; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| int rc = 0; |
| int lower_byte_offset = 0; |
| int orig_byte_offset = 0; |
| int num_extents_per_page; |
| #define ECRYPTFS_PAGE_STATE_UNREAD 0 |
| #define ECRYPTFS_PAGE_STATE_READ 1 |
| #define ECRYPTFS_PAGE_STATE_MODIFIED 2 |
| #define ECRYPTFS_PAGE_STATE_WRITTEN 3 |
| int page_state; |
| |
| lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host); |
| inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host); |
| crypt_stat = &inode_info->crypt_stat; |
| if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { |
| rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode, |
| ctx->param.lower_file); |
| if (rc) |
| ecryptfs_printk(KERN_ERR, "Error attempting to copy " |
| "page at index [0x%.16x]\n", |
| ctx->page->index); |
| goto out; |
| } |
| num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| base_extent = (ctx->page->index * num_extents_per_page); |
| page_state = ECRYPTFS_PAGE_STATE_UNREAD; |
| while (extent_offset < num_extents_per_page) { |
| ecryptfs_extent_to_lwr_pg_idx_and_offset( |
| &lower_page_idx, &lower_byte_offset, crypt_stat, |
| (base_extent + extent_offset)); |
| if (prior_lower_page_idx != lower_page_idx |
| && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) { |
| rc = ecryptfs_write_out_page(ctx, lower_page, |
| lower_inode, |
| orig_byte_offset, |
| (PAGE_CACHE_SIZE |
| - orig_byte_offset)); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error attempting " |
| "to write out page; rc = [%d]" |
| "\n", rc); |
| goto out; |
| } |
| page_state = ECRYPTFS_PAGE_STATE_WRITTEN; |
| } |
| if (page_state == ECRYPTFS_PAGE_STATE_UNREAD |
| || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) { |
| rc = ecryptfs_read_in_page(ctx, &lower_page, |
| lower_inode, lower_page_idx, |
| lower_byte_offset); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error attempting " |
| "to read in lower page with " |
| "index [0x%.16x]; rc = [%d]\n", |
| lower_page_idx, rc); |
| goto out; |
| } |
| orig_byte_offset = lower_byte_offset; |
| prior_lower_page_idx = lower_page_idx; |
| page_state = ECRYPTFS_PAGE_STATE_READ; |
| } |
| BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED |
| || page_state == ECRYPTFS_PAGE_STATE_READ)); |
| rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
| (base_extent + extent_offset)); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error attempting to " |
| "derive IV for extent [0x%.16x]; " |
| "rc = [%d]\n", |
| (base_extent + extent_offset), rc); |
| goto out; |
| } |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "Encrypting extent " |
| "with iv:\n"); |
| ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); |
| ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " |
| "encryption:\n"); |
| ecryptfs_dump_hex((char *) |
| (page_address(ctx->page) |
| + (extent_offset |
| * crypt_stat->extent_size)), 8); |
| } |
| rc = ecryptfs_encrypt_page_offset( |
| crypt_stat, lower_page, lower_byte_offset, ctx->page, |
| (extent_offset * crypt_stat->extent_size), |
| crypt_stat->extent_size, extent_iv); |
| ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " |
| "rc = [%d]\n", |
| (base_extent + extent_offset), rc); |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " |
| "encryption:\n"); |
| ecryptfs_dump_hex((char *)(page_address(lower_page) |
| + lower_byte_offset), 8); |
| } |
| page_state = ECRYPTFS_PAGE_STATE_MODIFIED; |
| extent_offset++; |
| } |
| BUG_ON(orig_byte_offset != 0); |
| rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0, |
| (lower_byte_offset |
| + crypt_stat->extent_size)); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error attempting to write out " |
| "page; rc = [%d]\n", rc); |
| goto out; |
| } |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_decrypt_page |
| * @file: The ecryptfs file |
| * @page: The page in ecryptfs to decrypt |
| * |
| * Decrypt an eCryptfs page. This is done on a per-extent basis. Note |
| * that eCryptfs pages may straddle the lower pages -- for instance, |
| * if the file was created on a machine with an 8K page size |
| * (resulting in an 8K header), and then the file is copied onto a |
| * host with a 32K page size, then when reading page 0 of the eCryptfs |
| * file, 24K of page 0 of the lower file will be read and decrypted, |
| * and then 8K of page 1 of the lower file will be read and decrypted. |
| * |
| * Returns zero on success; negative on error |
| */ |
| int ecryptfs_decrypt_page(struct file *file, struct page *page) |
| { |
| char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
| unsigned long base_extent; |
| unsigned long extent_offset = 0; |
| unsigned long lower_page_idx = 0; |
| unsigned long prior_lower_page_idx = 0; |
| struct page *lower_page; |
| char *lower_page_virt = NULL; |
| struct inode *lower_inode; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| int rc = 0; |
| int byte_offset; |
| int num_extents_per_page; |
| int page_state; |
| |
| crypt_stat = &(ecryptfs_inode_to_private( |
| page->mapping->host)->crypt_stat); |
| lower_inode = ecryptfs_inode_to_lower(page->mapping->host); |
| if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { |
| rc = ecryptfs_do_readpage(file, page, page->index); |
| if (rc) |
| ecryptfs_printk(KERN_ERR, "Error attempting to copy " |
| "page at index [0x%.16x]\n", |
| page->index); |
| goto out; |
| } |
| num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| base_extent = (page->index * num_extents_per_page); |
| lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache, |
| GFP_KERNEL); |
| if (!lower_page_virt) { |
| rc = -ENOMEM; |
| ecryptfs_printk(KERN_ERR, "Error getting page for encrypted " |
| "lower page(s)\n"); |
| goto out; |
| } |
| lower_page = virt_to_page(lower_page_virt); |
| page_state = ECRYPTFS_PAGE_STATE_UNREAD; |
| while (extent_offset < num_extents_per_page) { |
| ecryptfs_extent_to_lwr_pg_idx_and_offset( |
| &lower_page_idx, &byte_offset, crypt_stat, |
| (base_extent + extent_offset)); |
| if (prior_lower_page_idx != lower_page_idx |
| || page_state == ECRYPTFS_PAGE_STATE_UNREAD) { |
| rc = ecryptfs_do_readpage(file, lower_page, |
| lower_page_idx); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error reading " |
| "lower encrypted page; rc = " |
| "[%d]\n", rc); |
| goto out; |
| } |
| prior_lower_page_idx = lower_page_idx; |
| page_state = ECRYPTFS_PAGE_STATE_READ; |
| } |
| rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
| (base_extent + extent_offset)); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error attempting to " |
| "derive IV for extent [0x%.16x]; rc = " |
| "[%d]\n", |
| (base_extent + extent_offset), rc); |
| goto out; |
| } |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "Decrypting extent " |
| "with iv:\n"); |
| ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); |
| ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " |
| "decryption:\n"); |
| ecryptfs_dump_hex((lower_page_virt + byte_offset), 8); |
| } |
| rc = ecryptfs_decrypt_page_offset(crypt_stat, page, |
| (extent_offset |
| * crypt_stat->extent_size), |
| lower_page, byte_offset, |
| crypt_stat->extent_size, |
| extent_iv); |
| if (rc != crypt_stat->extent_size) { |
| ecryptfs_printk(KERN_ERR, "Error attempting to " |
| "decrypt extent [0x%.16x]\n", |
| (base_extent + extent_offset)); |
| goto out; |
| } |
| rc = 0; |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " |
| "decryption:\n"); |
| ecryptfs_dump_hex((char *)(page_address(page) |
| + byte_offset), 8); |
| } |
| extent_offset++; |
| } |
| out: |
| if (lower_page_virt) |
| kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt); |
| return rc; |
| } |
| |
| /** |
| * decrypt_scatterlist |
| * |
| * Returns the number of bytes decrypted; negative value on error |
| */ |
| static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
| struct scatterlist *dest_sg, |
| struct scatterlist *src_sg, int size, |
| unsigned char *iv) |
| { |
| struct blkcipher_desc desc = { |
| .tfm = crypt_stat->tfm, |
| .info = iv, |
| .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| }; |
| int rc = 0; |
| |
| /* Consider doing this once, when the file is opened */ |
| mutex_lock(&crypt_stat->cs_tfm_mutex); |
| rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
| crypt_stat->key_size); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", |
| rc); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| rc = -EINVAL; |
| goto out; |
| } |
| ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size); |
| rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n", |
| rc); |
| goto out; |
| } |
| rc = size; |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_encrypt_page_offset |
| * |
| * Returns the number of bytes encrypted |
| */ |
| static int |
| ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| struct page *dst_page, int dst_offset, |
| struct page *src_page, int src_offset, int size, |
| unsigned char *iv) |
| { |
| struct scatterlist src_sg, dst_sg; |
| |
| src_sg.page = src_page; |
| src_sg.offset = src_offset; |
| src_sg.length = size; |
| dst_sg.page = dst_page; |
| dst_sg.offset = dst_offset; |
| dst_sg.length = size; |
| return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); |
| } |
| |
| /** |
| * ecryptfs_decrypt_page_offset |
| * |
| * Returns the number of bytes decrypted |
| */ |
| static int |
| ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| struct page *dst_page, int dst_offset, |
| struct page *src_page, int src_offset, int size, |
| unsigned char *iv) |
| { |
| struct scatterlist src_sg, dst_sg; |
| |
| src_sg.page = src_page; |
| src_sg.offset = src_offset; |
| src_sg.length = size; |
| dst_sg.page = dst_page; |
| dst_sg.offset = dst_offset; |
| dst_sg.length = size; |
| return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); |
| } |
| |
| #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 |
| |
| /** |
| * ecryptfs_init_crypt_ctx |
| * @crypt_stat: Uninitilized crypt stats structure |
| * |
| * Initialize the crypto context. |
| * |
| * TODO: Performance: Keep a cache of initialized cipher contexts; |
| * only init if needed |
| */ |
| int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| char *full_alg_name; |
| int rc = -EINVAL; |
| |
| if (!crypt_stat->cipher) { |
| ecryptfs_printk(KERN_ERR, "No cipher specified\n"); |
| goto out; |
| } |
| ecryptfs_printk(KERN_DEBUG, |
| "Initializing cipher [%s]; strlen = [%d]; " |
| "key_size_bits = [%d]\n", |
| crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
| crypt_stat->key_size << 3); |
| if (crypt_stat->tfm) { |
| rc = 0; |
| goto out; |
| } |
| mutex_lock(&crypt_stat->cs_tfm_mutex); |
| rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
| crypt_stat->cipher, "cbc"); |
| if (rc) |
| goto out; |
| crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0, |
| CRYPTO_ALG_ASYNC); |
| kfree(full_alg_name); |
| if (IS_ERR(crypt_stat->tfm)) { |
| rc = PTR_ERR(crypt_stat->tfm); |
| ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
| "Error initializing cipher [%s]\n", |
| crypt_stat->cipher); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| goto out; |
| } |
| crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
| mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| rc = 0; |
| out: |
| return rc; |
| } |
| |
| static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| int extent_size_tmp; |
| |
| crypt_stat->extent_mask = 0xFFFFFFFF; |
| crypt_stat->extent_shift = 0; |
| if (crypt_stat->extent_size == 0) |
| return; |
| extent_size_tmp = crypt_stat->extent_size; |
| while ((extent_size_tmp & 0x01) == 0) { |
| extent_size_tmp >>= 1; |
| crypt_stat->extent_mask <<= 1; |
| crypt_stat->extent_shift++; |
| } |
| } |
| |
| void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| /* Default values; may be overwritten as we are parsing the |
| * packets. */ |
| crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; |
| set_extent_mask_and_shift(crypt_stat); |
| crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; |
| if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) { |
| crypt_stat->header_extent_size = |
| ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
| } else |
| crypt_stat->header_extent_size = PAGE_CACHE_SIZE; |
| if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| crypt_stat->num_header_extents_at_front = 0; |
| else |
| crypt_stat->num_header_extents_at_front = 1; |
| } |
| |
| /** |
| * ecryptfs_compute_root_iv |
| * @crypt_stats |
| * |
| * On error, sets the root IV to all 0's. |
| */ |
| int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| int rc = 0; |
| char dst[MD5_DIGEST_SIZE]; |
| |
| BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); |
| BUG_ON(crypt_stat->iv_bytes <= 0); |
| if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID)) { |
| rc = -EINVAL; |
| ecryptfs_printk(KERN_WARNING, "Session key not valid; " |
| "cannot generate root IV\n"); |
| goto out; |
| } |
| rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, |
| crypt_stat->key_size); |
| if (rc) { |
| ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| "MD5 while generating root IV\n"); |
| goto out; |
| } |
| memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); |
| out: |
| if (rc) { |
| memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, |
| ECRYPTFS_SECURITY_WARNING); |
| } |
| return rc; |
| } |
| |
| static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| get_random_bytes(crypt_stat->key, crypt_stat->key_size); |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| ecryptfs_compute_root_iv(crypt_stat); |
| if (unlikely(ecryptfs_verbosity > 0)) { |
| ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); |
| ecryptfs_dump_hex(crypt_stat->key, |
| crypt_stat->key_size); |
| } |
| } |
| |
| /** |
| * ecryptfs_copy_mount_wide_flags_to_inode_flags |
| * |
| * This function propagates the mount-wide flags to individual inode |
| * flags. |
| */ |
| static void ecryptfs_copy_mount_wide_flags_to_inode_flags( |
| struct ecryptfs_crypt_stat *crypt_stat, |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| { |
| if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) |
| crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
| if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
| crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; |
| } |
| |
| /** |
| * ecryptfs_set_default_crypt_stat_vals |
| * @crypt_stat |
| * |
| * Default values in the event that policy does not override them. |
| */ |
| static void ecryptfs_set_default_crypt_stat_vals( |
| struct ecryptfs_crypt_stat *crypt_stat, |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| { |
| ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| mount_crypt_stat); |
| ecryptfs_set_default_sizes(crypt_stat); |
| strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); |
| crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; |
| ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
| crypt_stat->mount_crypt_stat = mount_crypt_stat; |
| } |
| |
| /** |
| * ecryptfs_new_file_context |
| * @ecryptfs_dentry |
| * |
| * If the crypto context for the file has not yet been established, |
| * this is where we do that. Establishing a new crypto context |
| * involves the following decisions: |
| * - What cipher to use? |
| * - What set of authentication tokens to use? |
| * Here we just worry about getting enough information into the |
| * authentication tokens so that we know that they are available. |
| * We associate the available authentication tokens with the new file |
| * via the set of signatures in the crypt_stat struct. Later, when |
| * the headers are actually written out, we may again defer to |
| * userspace to perform the encryption of the session key; for the |
| * foreseeable future, this will be the case with public key packets. |
| * |
| * Returns zero on success; non-zero otherwise |
| */ |
| /* Associate an authentication token(s) with the file */ |
| int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry) |
| { |
| int rc = 0; |
| struct ecryptfs_crypt_stat *crypt_stat = |
| &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| &ecryptfs_superblock_to_private( |
| ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| int cipher_name_len; |
| |
| ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); |
| /* See if there are mount crypt options */ |
| if (mount_crypt_stat->global_auth_tok) { |
| ecryptfs_printk(KERN_DEBUG, "Initializing context for new " |
| "file using mount_crypt_stat\n"); |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED); |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| mount_crypt_stat); |
| memcpy(crypt_stat->keysigs[crypt_stat->num_keysigs++], |
| mount_crypt_stat->global_auth_tok_sig, |
| ECRYPTFS_SIG_SIZE_HEX); |
| cipher_name_len = |
| strlen(mount_crypt_stat->global_default_cipher_name); |
| memcpy(crypt_stat->cipher, |
| mount_crypt_stat->global_default_cipher_name, |
| cipher_name_len); |
| crypt_stat->cipher[cipher_name_len] = '\0'; |
| crypt_stat->key_size = |
| mount_crypt_stat->global_default_cipher_key_size; |
| ecryptfs_generate_new_key(crypt_stat); |
| } else |
| /* We should not encounter this scenario since we |
| * should detect lack of global_auth_tok at mount time |
| * TODO: Applies to 0.1 release only; remove in future |
| * release */ |
| BUG(); |
| rc = ecryptfs_init_crypt_ctx(crypt_stat); |
| if (rc) |
| ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " |
| "context for cipher [%s]: rc = [%d]\n", |
| crypt_stat->cipher, rc); |
| return rc; |
| } |
| |
| /** |
| * contains_ecryptfs_marker - check for the ecryptfs marker |
| * @data: The data block in which to check |
| * |
| * Returns one if marker found; zero if not found |
| */ |
| static int contains_ecryptfs_marker(char *data) |
| { |
| u32 m_1, m_2; |
| |
| memcpy(&m_1, data, 4); |
| m_1 = be32_to_cpu(m_1); |
| memcpy(&m_2, (data + 4), 4); |
| m_2 = be32_to_cpu(m_2); |
| if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
| return 1; |
| ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
| "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, |
| MAGIC_ECRYPTFS_MARKER); |
| ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " |
| "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); |
| return 0; |
| } |
| |
| struct ecryptfs_flag_map_elem { |
| u32 file_flag; |
| u32 local_flag; |
| }; |
| |
| /* Add support for additional flags by adding elements here. */ |
| static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { |
| {0x00000001, ECRYPTFS_ENABLE_HMAC}, |
| {0x00000002, ECRYPTFS_ENCRYPTED}, |
| {0x00000004, ECRYPTFS_METADATA_IN_XATTR} |
| }; |
| |
| /** |
| * ecryptfs_process_flags |
| * @crypt_stat |
| * @page_virt: Source data to be parsed |
| * @bytes_read: Updated with the number of bytes read |
| * |
| * Returns zero on success; non-zero if the flag set is invalid |
| */ |
| static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
| char *page_virt, int *bytes_read) |
| { |
| int rc = 0; |
| int i; |
| u32 flags; |
| |
| memcpy(&flags, page_virt, 4); |
| flags = be32_to_cpu(flags); |
| for (i = 0; i < ((sizeof(ecryptfs_flag_map) |
| / sizeof(struct ecryptfs_flag_map_elem))); i++) |
| if (flags & ecryptfs_flag_map[i].file_flag) { |
| ECRYPTFS_SET_FLAG(crypt_stat->flags, |
| ecryptfs_flag_map[i].local_flag); |
| } else |
| ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, |
| ecryptfs_flag_map[i].local_flag); |
| /* Version is in top 8 bits of the 32-bit flag vector */ |
| crypt_stat->file_version = ((flags >> 24) & 0xFF); |
| (*bytes_read) = 4; |
| return rc; |
| } |
| |
| /** |
| * write_ecryptfs_marker |
| * @page_virt: The pointer to in a page to begin writing the marker |
| * @written: Number of bytes written |
| * |
| * Marker = 0x3c81b7f5 |
| */ |
| static void write_ecryptfs_marker(char *page_virt, size_t *written) |
| { |
| u32 m_1, m_2; |
| |
| get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); |
| m_1 = cpu_to_be32(m_1); |
| memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| m_2 = cpu_to_be32(m_2); |
| memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2, |
| (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| } |
| |
| static void |
| write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat, |
| size_t *written) |
| { |
| u32 flags = 0; |
| int i; |
| |
| for (i = 0; i < ((sizeof(ecryptfs_flag_map) |
| / sizeof(struct ecryptfs_flag_map_elem))); i++) |
| if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| ecryptfs_flag_map[i].local_flag)) |
| flags |= ecryptfs_flag_map[i].file_flag; |
| /* Version is in top 8 bits of the 32-bit flag vector */ |
| flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); |
| flags = cpu_to_be32(flags); |
| memcpy(page_virt, &flags, 4); |
| (*written) = 4; |
| } |
| |
| struct ecryptfs_cipher_code_str_map_elem { |
| char cipher_str[16]; |
| u16 cipher_code; |
| }; |
| |
| /* Add support for additional ciphers by adding elements here. The |
| * cipher_code is whatever OpenPGP applicatoins use to identify the |
| * ciphers. List in order of probability. */ |
| static struct ecryptfs_cipher_code_str_map_elem |
| ecryptfs_cipher_code_str_map[] = { |
| {"aes",RFC2440_CIPHER_AES_128 }, |
| {"blowfish", RFC2440_CIPHER_BLOWFISH}, |
| {"des3_ede", RFC2440_CIPHER_DES3_EDE}, |
| {"cast5", RFC2440_CIPHER_CAST_5}, |
| {"twofish", RFC2440_CIPHER_TWOFISH}, |
| {"cast6", RFC2440_CIPHER_CAST_6}, |
| {"aes", RFC2440_CIPHER_AES_192}, |
| {"aes", RFC2440_CIPHER_AES_256} |
| }; |
| |
| /** |
| * ecryptfs_code_for_cipher_string |
| * @str: The string representing the cipher name |
| * |
| * Returns zero on no match, or the cipher code on match |
| */ |
| u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| int i; |
| u16 code = 0; |
| struct ecryptfs_cipher_code_str_map_elem *map = |
| ecryptfs_cipher_code_str_map; |
| |
| if (strcmp(crypt_stat->cipher, "aes") == 0) { |
| switch (crypt_stat->key_size) { |
| case 16: |
| code = RFC2440_CIPHER_AES_128; |
| break; |
| case 24: |
| code = RFC2440_CIPHER_AES_192; |
| break; |
| case 32: |
| code = RFC2440_CIPHER_AES_256; |
| } |
| } else { |
| for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){ |
| code = map[i].cipher_code; |
| break; |
| } |
| } |
| return code; |
| } |
| |
| /** |
| * ecryptfs_cipher_code_to_string |
| * @str: Destination to write out the cipher name |
| * @cipher_code: The code to convert to cipher name string |
| * |
| * Returns zero on success |
| */ |
| int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code) |
| { |
| int rc = 0; |
| int i; |
| |
| str[0] = '\0'; |
| for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) |
| strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); |
| if (str[0] == '\0') { |
| ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " |
| "[%d]\n", cipher_code); |
| rc = -EINVAL; |
| } |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_read_header_region |
| * @data |
| * @dentry |
| * @nd |
| * |
| * Returns zero on success; non-zero otherwise |
| */ |
| static int ecryptfs_read_header_region(char *data, struct dentry *dentry, |
| struct vfsmount *mnt) |
| { |
| struct file *lower_file; |
| mm_segment_t oldfs; |
| int rc; |
| |
| if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, |
| O_RDONLY))) { |
| printk(KERN_ERR |
| "Error opening lower_file to read header region\n"); |
| goto out; |
| } |
| lower_file->f_pos = 0; |
| oldfs = get_fs(); |
| set_fs(get_ds()); |
| /* For releases 0.1 and 0.2, all of the header information |
| * fits in the first data extent-sized region. */ |
| rc = lower_file->f_op->read(lower_file, (char __user *)data, |
| ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos); |
| set_fs(oldfs); |
| if ((rc = ecryptfs_close_lower_file(lower_file))) { |
| printk(KERN_ERR "Error closing lower_file\n"); |
| goto out; |
| } |
| rc = 0; |
| out: |
| return rc; |
| } |
| |
| int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry, |
| struct vfsmount *mnt) |
| { |
| int rc; |
| |
| rc = ecryptfs_read_header_region(data, dentry, mnt); |
| if (rc) |
| goto out; |
| if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) |
| rc = -EINVAL; |
| out: |
| return rc; |
| } |
| |
| |
| void |
| ecryptfs_write_header_metadata(char *virt, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| size_t *written) |
| { |
| u32 header_extent_size; |
| u16 num_header_extents_at_front; |
| |
| header_extent_size = (u32)crypt_stat->header_extent_size; |
| num_header_extents_at_front = |
| (u16)crypt_stat->num_header_extents_at_front; |
| header_extent_size = cpu_to_be32(header_extent_size); |
| memcpy(virt, &header_extent_size, 4); |
| virt += 4; |
| num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front); |
| memcpy(virt, &num_header_extents_at_front, 2); |
| (*written) = 6; |
| } |
| |
| struct kmem_cache *ecryptfs_header_cache_0; |
| struct kmem_cache *ecryptfs_header_cache_1; |
| struct kmem_cache *ecryptfs_header_cache_2; |
| |
| /** |
| * ecryptfs_write_headers_virt |
| * @page_virt |
| * @crypt_stat |
| * @ecryptfs_dentry |
| * |
| * Format version: 1 |
| * |
| * Header Extent: |
| * Octets 0-7: Unencrypted file size (big-endian) |
| * Octets 8-15: eCryptfs special marker |
| * Octets 16-19: Flags |
| * Octet 16: File format version number (between 0 and 255) |
| * Octets 17-18: Reserved |
| * Octet 19: Bit 1 (lsb): Reserved |
| * Bit 2: Encrypted? |
| * Bits 3-8: Reserved |
| * Octets 20-23: Header extent size (big-endian) |
| * Octets 24-25: Number of header extents at front of file |
| * (big-endian) |
| * Octet 26: Begin RFC 2440 authentication token packet set |
| * Data Extent 0: |
| * Lower data (CBC encrypted) |
| * Data Extent 1: |
| * Lower data (CBC encrypted) |
| * ... |
| * |
| * Returns zero on success |
| */ |
| static int ecryptfs_write_headers_virt(char *page_virt, size_t *size, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| struct dentry *ecryptfs_dentry) |
| { |
| int rc; |
| size_t written; |
| size_t offset; |
| |
| offset = ECRYPTFS_FILE_SIZE_BYTES; |
| write_ecryptfs_marker((page_virt + offset), &written); |
| offset += written; |
| write_ecryptfs_flags((page_virt + offset), crypt_stat, &written); |
| offset += written; |
| ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
| &written); |
| offset += written; |
| rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, |
| ecryptfs_dentry, &written, |
| PAGE_CACHE_SIZE - offset); |
| if (rc) |
| ecryptfs_printk(KERN_WARNING, "Error generating key packet " |
| "set; rc = [%d]\n", rc); |
| if (size) { |
| offset += written; |
| *size = offset; |
| } |
| return rc; |
| } |
| |
| static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat, |
| struct file *lower_file, |
| char *page_virt) |
| { |
| mm_segment_t oldfs; |
| int current_header_page; |
| int header_pages; |
| ssize_t size; |
| int rc = 0; |
| |
| lower_file->f_pos = 0; |
| oldfs = get_fs(); |
| set_fs(get_ds()); |
| size = vfs_write(lower_file, (char __user *)page_virt, PAGE_CACHE_SIZE, |
| &lower_file->f_pos); |
| if (size < 0) { |
| rc = (int)size; |
| printk(KERN_ERR "Error attempting to write lower page; " |
| "rc = [%d]\n", rc); |
| set_fs(oldfs); |
| goto out; |
| } |
| header_pages = ((crypt_stat->header_extent_size |
| * crypt_stat->num_header_extents_at_front) |
| / PAGE_CACHE_SIZE); |
| memset(page_virt, 0, PAGE_CACHE_SIZE); |
| current_header_page = 1; |
| while (current_header_page < header_pages) { |
| size = vfs_write(lower_file, (char __user *)page_virt, |
| PAGE_CACHE_SIZE, &lower_file->f_pos); |
| if (size < 0) { |
| rc = (int)size; |
| printk(KERN_ERR "Error attempting to write lower page; " |
| "rc = [%d]\n", rc); |
| set_fs(oldfs); |
| goto out; |
| } |
| current_header_page++; |
| } |
| set_fs(oldfs); |
| out: |
| return rc; |
| } |
| |
| static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| char *page_virt, size_t size) |
| { |
| int rc; |
| |
| rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt, |
| size, 0); |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_write_metadata |
| * @lower_file: The lower file struct, which was returned from dentry_open |
| * |
| * Write the file headers out. This will likely involve a userspace |
| * callout, in which the session key is encrypted with one or more |
| * public keys and/or the passphrase necessary to do the encryption is |
| * retrieved via a prompt. Exactly what happens at this point should |
| * be policy-dependent. |
| * |
| * Returns zero on success; non-zero on error |
| */ |
| int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
| struct file *lower_file) |
| { |
| struct ecryptfs_crypt_stat *crypt_stat; |
| char *page_virt; |
| size_t size; |
| int rc = 0; |
| |
| crypt_stat = &ecryptfs_inode_to_private( |
| ecryptfs_dentry->d_inode)->crypt_stat; |
| if (likely(ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| ECRYPTFS_ENCRYPTED))) { |
| if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| ECRYPTFS_KEY_VALID)) { |
| ecryptfs_printk(KERN_DEBUG, "Key is " |
| "invalid; bailing out\n"); |
| rc = -EINVAL; |
| goto out; |
| } |
| } else { |
| rc = -EINVAL; |
| ecryptfs_printk(KERN_WARNING, |
| "Called with crypt_stat->encrypted == 0\n"); |
| goto out; |
| } |
| /* Released in this function */ |
| page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER); |
| if (!page_virt) { |
| ecryptfs_printk(KERN_ERR, "Out of memory\n"); |
| rc = -ENOMEM; |
| goto out; |
| } |
| rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat, |
| ecryptfs_dentry); |
| if (unlikely(rc)) { |
| ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n"); |
| memset(page_virt, 0, PAGE_CACHE_SIZE); |
| goto out_free; |
| } |
| if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, |
| crypt_stat, page_virt, |
| size); |
| else |
| rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file, |
| page_virt); |
| if (rc) { |
| printk(KERN_ERR "Error writing metadata out to lower file; " |
| "rc = [%d]\n", rc); |
| goto out_free; |
| } |
| out_free: |
| kmem_cache_free(ecryptfs_header_cache_0, page_virt); |
| out: |
| return rc; |
| } |
| |
| #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
| #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 |
| static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
| char *virt, int *bytes_read, |
| int validate_header_size) |
| { |
| int rc = 0; |
| u32 header_extent_size; |
| u16 num_header_extents_at_front; |
| |
| memcpy(&header_extent_size, virt, 4); |
| header_extent_size = be32_to_cpu(header_extent_size); |
| virt += 4; |
| memcpy(&num_header_extents_at_front, virt, 2); |
| num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front); |
| crypt_stat->header_extent_size = (int)header_extent_size; |
| crypt_stat->num_header_extents_at_front = |
| (int)num_header_extents_at_front; |
| (*bytes_read) = 6; |
| if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
| && ((crypt_stat->header_extent_size |
| * crypt_stat->num_header_extents_at_front) |
| < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
| rc = -EINVAL; |
| ecryptfs_printk(KERN_WARNING, "Invalid header extent size: " |
| "[%d]\n", crypt_stat->header_extent_size); |
| } |
| return rc; |
| } |
| |
| /** |
| * set_default_header_data |
| * |
| * For version 0 file format; this function is only for backwards |
| * compatibility for files created with the prior versions of |
| * eCryptfs. |
| */ |
| static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) |
| { |
| crypt_stat->header_extent_size = 4096; |
| crypt_stat->num_header_extents_at_front = 1; |
| } |
| |
| /** |
| * ecryptfs_read_headers_virt |
| * |
| * Read/parse the header data. The header format is detailed in the |
| * comment block for the ecryptfs_write_headers_virt() function. |
| * |
| * Returns zero on success |
| */ |
| static int ecryptfs_read_headers_virt(char *page_virt, |
| struct ecryptfs_crypt_stat *crypt_stat, |
| struct dentry *ecryptfs_dentry, |
| int validate_header_size) |
| { |
| int rc = 0; |
| int offset; |
| int bytes_read; |
| |
| ecryptfs_set_default_sizes(crypt_stat); |
| crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( |
| ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| offset = ECRYPTFS_FILE_SIZE_BYTES; |
| rc = contains_ecryptfs_marker(page_virt + offset); |
| if (rc == 0) { |
| rc = -EINVAL; |
| goto out; |
| } |
| offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), |
| &bytes_read); |
| if (rc) { |
| ecryptfs_printk(KERN_WARNING, "Error processing flags\n"); |
| goto out; |
| } |
| if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
| ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " |
| "file version [%d] is supported by this " |
| "version of eCryptfs\n", |
| crypt_stat->file_version, |
| ECRYPTFS_SUPPORTED_FILE_VERSION); |
| rc = -EINVAL; |
| goto out; |
| } |
| offset += bytes_read; |
| if (crypt_stat->file_version >= 1) { |
| rc = parse_header_metadata(crypt_stat, (page_virt + offset), |
| &bytes_read, validate_header_size); |
| if (rc) { |
| ecryptfs_printk(KERN_WARNING, "Error reading header " |
| "metadata; rc = [%d]\n", rc); |
| } |
| offset += bytes_read; |
| } else |
| set_default_header_data(crypt_stat); |
| rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), |
| ecryptfs_dentry); |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_read_xattr_region |
| * |
| * Attempts to read the crypto metadata from the extended attribute |
| * region of the lower file. |
| */ |
| int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry) |
| { |
| ssize_t size; |
| int rc = 0; |
| |
| size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, |
| page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
| if (size < 0) { |
| printk(KERN_DEBUG "Error attempting to read the [%s] " |
| "xattr from the lower file; return value = [%zd]\n", |
| ECRYPTFS_XATTR_NAME, size); |
| rc = -EINVAL; |
| goto out; |
| } |
| out: |
| return rc; |
| } |
| |
| int ecryptfs_read_and_validate_xattr_region(char *page_virt, |
| struct dentry *ecryptfs_dentry) |
| { |
| int rc; |
| |
| rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry); |
| if (rc) |
| goto out; |
| if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) { |
| printk(KERN_WARNING "Valid data found in [%s] xattr, but " |
| "the marker is invalid\n", ECRYPTFS_XATTR_NAME); |
| rc = -EINVAL; |
| } |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_read_metadata |
| * |
| * Common entry point for reading file metadata. From here, we could |
| * retrieve the header information from the header region of the file, |
| * the xattr region of the file, or some other repostory that is |
| * stored separately from the file itself. The current implementation |
| * supports retrieving the metadata information from the file contents |
| * and from the xattr region. |
| * |
| * Returns zero if valid headers found and parsed; non-zero otherwise |
| */ |
| int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry, |
| struct file *lower_file) |
| { |
| int rc = 0; |
| char *page_virt = NULL; |
| mm_segment_t oldfs; |
| ssize_t bytes_read; |
| struct ecryptfs_crypt_stat *crypt_stat = |
| &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| &ecryptfs_superblock_to_private( |
| ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| |
| ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| mount_crypt_stat); |
| /* Read the first page from the underlying file */ |
| page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER); |
| if (!page_virt) { |
| rc = -ENOMEM; |
| ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n"); |
| goto out; |
| } |
| lower_file->f_pos = 0; |
| oldfs = get_fs(); |
| set_fs(get_ds()); |
| bytes_read = lower_file->f_op->read(lower_file, |
| (char __user *)page_virt, |
| ECRYPTFS_DEFAULT_EXTENT_SIZE, |
| &lower_file->f_pos); |
| set_fs(oldfs); |
| if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) { |
| rc = -EINVAL; |
| goto out; |
| } |
| rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
| ecryptfs_dentry, |
| ECRYPTFS_VALIDATE_HEADER_SIZE); |
| if (rc) { |
| rc = ecryptfs_read_xattr_region(page_virt, |
| ecryptfs_dentry); |
| if (rc) { |
| printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
| "file header region or xattr region\n"); |
| rc = -EINVAL; |
| goto out; |
| } |
| rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
| ecryptfs_dentry, |
| ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); |
| if (rc) { |
| printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
| "file xattr region either\n"); |
| rc = -EINVAL; |
| } |
| if (crypt_stat->mount_crypt_stat->flags |
| & ECRYPTFS_XATTR_METADATA_ENABLED) { |
| crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
| } else { |
| printk(KERN_WARNING "Attempt to access file with " |
| "crypto metadata only in the extended attribute " |
| "region, but eCryptfs was mounted without " |
| "xattr support enabled. eCryptfs will not treat " |
| "this like an encrypted file.\n"); |
| rc = -EINVAL; |
| } |
| } |
| out: |
| if (page_virt) { |
| memset(page_virt, 0, PAGE_CACHE_SIZE); |
| kmem_cache_free(ecryptfs_header_cache_1, page_virt); |
| } |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_encode_filename - converts a plaintext file name to cipher text |
| * @crypt_stat: The crypt_stat struct associated with the file anem to encode |
| * @name: The plaintext name |
| * @length: The length of the plaintext |
| * @encoded_name: The encypted name |
| * |
| * Encrypts and encodes a filename into something that constitutes a |
| * valid filename for a filesystem, with printable characters. |
| * |
| * We assume that we have a properly initialized crypto context, |
| * pointed to by crypt_stat->tfm. |
| * |
| * TODO: Implement filename decoding and decryption here, in place of |
| * memcpy. We are keeping the framework around for now to (1) |
| * facilitate testing of the components needed to implement filename |
| * encryption and (2) to provide a code base from which other |
| * developers in the community can easily implement this feature. |
| * |
| * Returns the length of encoded filename; negative if error |
| */ |
| int |
| ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat, |
| const char *name, int length, char **encoded_name) |
| { |
| int error = 0; |
| |
| (*encoded_name) = kmalloc(length + 2, GFP_KERNEL); |
| if (!(*encoded_name)) { |
| error = -ENOMEM; |
| goto out; |
| } |
| /* TODO: Filename encryption is a scheduled feature for a |
| * future version of eCryptfs. This function is here only for |
| * the purpose of providing a framework for other developers |
| * to easily implement filename encryption. Hint: Replace this |
| * memcpy() with a call to encrypt and encode the |
| * filename, the set the length accordingly. */ |
| memcpy((void *)(*encoded_name), (void *)name, length); |
| (*encoded_name)[length] = '\0'; |
| error = length + 1; |
| out: |
| return error; |
| } |
| |
| /** |
| * ecryptfs_decode_filename - converts the cipher text name to plaintext |
| * @crypt_stat: The crypt_stat struct associated with the file |
| * @name: The filename in cipher text |
| * @length: The length of the cipher text name |
| * @decrypted_name: The plaintext name |
| * |
| * Decodes and decrypts the filename. |
| * |
| * We assume that we have a properly initialized crypto context, |
| * pointed to by crypt_stat->tfm. |
| * |
| * TODO: Implement filename decoding and decryption here, in place of |
| * memcpy. We are keeping the framework around for now to (1) |
| * facilitate testing of the components needed to implement filename |
| * encryption and (2) to provide a code base from which other |
| * developers in the community can easily implement this feature. |
| * |
| * Returns the length of decoded filename; negative if error |
| */ |
| int |
| ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, |
| const char *name, int length, char **decrypted_name) |
| { |
| int error = 0; |
| |
| (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL); |
| if (!(*decrypted_name)) { |
| error = -ENOMEM; |
| goto out; |
| } |
| /* TODO: Filename encryption is a scheduled feature for a |
| * future version of eCryptfs. This function is here only for |
| * the purpose of providing a framework for other developers |
| * to easily implement filename encryption. Hint: Replace this |
| * memcpy() with a call to decode and decrypt the |
| * filename, the set the length accordingly. */ |
| memcpy((void *)(*decrypted_name), (void *)name, length); |
| (*decrypted_name)[length + 1] = '\0'; /* Only for convenience |
| * in printing out the |
| * string in debug |
| * messages */ |
| error = length; |
| out: |
| return error; |
| } |
| |
| /** |
| * ecryptfs_process_cipher - Perform cipher initialization. |
| * @key_tfm: Crypto context for key material, set by this function |
| * @cipher_name: Name of the cipher |
| * @key_size: Size of the key in bytes |
| * |
| * Returns zero on success. Any crypto_tfm structs allocated here |
| * should be released by other functions, such as on a superblock put |
| * event, regardless of whether this function succeeds for fails. |
| */ |
| int |
| ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name, |
| size_t *key_size) |
| { |
| char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; |
| char *full_alg_name; |
| int rc; |
| |
| *key_tfm = NULL; |
| if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { |
| rc = -EINVAL; |
| printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum " |
| "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
| goto out; |
| } |
| rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
| "ecb"); |
| if (rc) |
| goto out; |
| *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
| kfree(full_alg_name); |
| if (IS_ERR(*key_tfm)) { |
| rc = PTR_ERR(*key_tfm); |
| printk(KERN_ERR "Unable to allocate crypto cipher with name " |
| "[%s]; rc = [%d]\n", cipher_name, rc); |
| goto out; |
| } |
| crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
| if (*key_size == 0) { |
| struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm); |
| |
| *key_size = alg->max_keysize; |
| } |
| get_random_bytes(dummy_key, *key_size); |
| rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size); |
| if (rc) { |
| printk(KERN_ERR "Error attempting to set key of size [%Zd] for " |
| "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc); |
| rc = -EINVAL; |
| goto out; |
| } |
| out: |
| return rc; |
| } |