--- /dev/null
+/**
+ * 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 <linux/slab.h>
+#include <asm/unaligned.h>
+#include "ecryptfs_kernel.h"
+
+#define DECRYPT 0
+#define ENCRYPT 1
+
+/**
+ * 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;
+ }
+ rc = crypto_hash_init(&desc);
+ if (rc) {
+ printk(KERN_ERR
+ "%s: Error initializing crypto hash; rc = [%d]\n",
+ __func__, rc);
+ goto out;
+ }
+ rc = crypto_hash_update(&desc, &sg, len);
+ if (rc) {
+ printk(KERN_ERR
+ "%s: Error updating crypto hash; rc = [%d]\n",
+ __func__, rc);
+ goto out;
+ }
+ rc = crypto_hash_final(&desc, dst);
+ if (rc) {
+ printk(KERN_ERR
+ "%s: Error finalizing crypto hash; rc = [%d]\n",
+ __func__, rc);
+ goto out;
+ }
+out:
+ mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
+ return rc;
+}
+
+static 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 extent whose 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.
+ */
+int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
+ loff_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, "%lld", 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));
+ INIT_LIST_HEAD(&crypt_stat->keysig_list);
+ mutex_init(&crypt_stat->keysig_list_mutex);
+ mutex_init(&crypt_stat->cs_mutex);
+ mutex_init(&crypt_stat->cs_tfm_mutex);
+ mutex_init(&crypt_stat->cs_hash_tfm_mutex);
+ crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
+}
+
+/**
+ * ecryptfs_destroy_crypt_stat
+ * @crypt_stat: Pointer to the crypt_stat struct to initialize.
+ *
+ * Releases all memory associated with a crypt_stat struct.
+ */
+void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
+{
+ struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
+
+ if (crypt_stat->tfm)
+ crypto_free_ablkcipher(crypt_stat->tfm);
+ if (crypt_stat->hash_tfm)
+ crypto_free_hash(crypt_stat->hash_tfm);
+ list_for_each_entry_safe(key_sig, key_sig_tmp,
+ &crypt_stat->keysig_list, crypt_stat_list) {
+ list_del(&key_sig->crypt_stat_list);
+ kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
+ }
+ memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
+}
+
+void ecryptfs_destroy_mount_crypt_stat(
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+ struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
+
+ if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
+ return;
+ mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+ list_for_each_entry_safe(auth_tok, auth_tok_tmp,
+ &mount_crypt_stat->global_auth_tok_list,
+ mount_crypt_stat_list) {
+ list_del(&auth_tok->mount_crypt_stat_list);
+ if (auth_tok->global_auth_tok_key
+ && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
+ key_put(auth_tok->global_auth_tok_key);
+ kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
+ }
+ mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+ 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;
+
+ sg_init_table(sg, sg_size);
+
+ while (size > 0 && i < sg_size) {
+ pg = virt_to_page(addr);
+ offset = offset_in_page(addr);
+ sg_set_page(&sg[i], pg, 0, offset);
+ remainder_of_page = PAGE_CACHE_SIZE - offset;
+ if (size >= remainder_of_page) {
+ sg[i].length = remainder_of_page;
+ addr += remainder_of_page;
+ size -= remainder_of_page;
+ } else {
+ sg[i].length = size;
+ addr += size;
+ size = 0;
+ }
+ i++;
+ }
+ if (size > 0)
+ return -ENOMEM;
+ return i;
+}
+
+struct extent_crypt_result {
+ struct completion completion;
+ int rc;
+};
+
+static void extent_crypt_complete(struct crypto_async_request *req, int rc)
+{
+ struct extent_crypt_result *ecr = req->data;
+
+ if (rc == -EINPROGRESS)
+ return;
+
+ ecr->rc = rc;
+ complete(&ecr->completion);
+}
+
+/**
+ * crypt_scatterlist
+ * @crypt_stat: Pointer to the crypt_stat struct to initialize.
+ * @dst_sg: Destination of the data after performing the crypto operation
+ * @src_sg: Data to be encrypted or decrypted
+ * @size: Length of data
+ * @iv: IV to use
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
+ *
+ * Returns the number of bytes encrypted or decrypted; negative value on error
+ */
+static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
+ struct scatterlist *dst_sg,
+ struct scatterlist *src_sg, int size,
+ unsigned char *iv, int op)
+{
+ struct ablkcipher_request *req = NULL;
+ struct extent_crypt_result ecr;
+ int rc = 0;
+
+ BUG_ON(!crypt_stat || !crypt_stat->tfm
+ || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
+ if (unlikely(ecryptfs_verbosity > 0)) {
+ ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
+ crypt_stat->key_size);
+ ecryptfs_dump_hex(crypt_stat->key,
+ crypt_stat->key_size);
+ }
+
+ init_completion(&ecr.completion);
+
+ mutex_lock(&crypt_stat->cs_tfm_mutex);
+ req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
+ if (!req) {
+ mutex_unlock(&crypt_stat->cs_tfm_mutex);
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ablkcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ extent_crypt_complete, &ecr);
+ /* Consider doing this once, when the file is opened */
+ if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
+ rc = crypto_ablkcipher_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;
+ }
+ crypt_stat->flags |= ECRYPTFS_KEY_SET;
+ }
+ mutex_unlock(&crypt_stat->cs_tfm_mutex);
+ ablkcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
+ rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) :
+ crypto_ablkcipher_decrypt(req);
+ if (rc == -EINPROGRESS || rc == -EBUSY) {
+ struct extent_crypt_result *ecr = req->base.data;
+
+ wait_for_completion(&ecr->completion);
+ rc = ecr->rc;
+ reinit_completion(&ecr->completion);
+ }
+out:
+ ablkcipher_request_free(req);
+ return rc;
+}
+
+/**
+ * lower_offset_for_page
+ *
+ * Convert an eCryptfs page index into a lower byte offset
+ */
+static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
+ struct page *page)
+{
+ return ecryptfs_lower_header_size(crypt_stat) +
+ ((loff_t)page->index << PAGE_CACHE_SHIFT);
+}
+
+/**
+ * crypt_extent
+ * @crypt_stat: crypt_stat containing cryptographic context for the
+ * encryption operation
+ * @dst_page: The page to write the result into
+ * @src_page: The page to read from
+ * @extent_offset: Page extent offset for use in generating IV
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
+ *
+ * Encrypts or decrypts one extent of data.
+ *
+ * Return zero on success; non-zero otherwise
+ */
+static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
+ struct page *dst_page,
+ struct page *src_page,
+ unsigned long extent_offset, int op)
+{
+ pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
+ loff_t extent_base;
+ char extent_iv[ECRYPTFS_MAX_IV_BYTES];
+ struct scatterlist src_sg, dst_sg;
+ size_t extent_size = crypt_stat->extent_size;
+ int rc;
+
+ extent_base = (((loff_t)page_index) * (PAGE_CACHE_SIZE / extent_size));
+ rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
+ (extent_base + extent_offset));
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
+ "extent [0x%.16llx]; rc = [%d]\n",
+ (unsigned long long)(extent_base + extent_offset), rc);
+ goto out;
+ }
+
+ sg_init_table(&src_sg, 1);
+ sg_init_table(&dst_sg, 1);
+
+ sg_set_page(&src_sg, src_page, extent_size,
+ extent_offset * extent_size);
+ sg_set_page(&dst_sg, dst_page, extent_size,
+ extent_offset * extent_size);
+
+ rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
+ extent_iv, op);
+ if (rc < 0) {
+ printk(KERN_ERR "%s: Error attempting to crypt page with "
+ "page_index = [%ld], extent_offset = [%ld]; "
+ "rc = [%d]\n", __func__, page_index, extent_offset, rc);
+ goto out;
+ }
+ rc = 0;
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_encrypt_page
+ * @page: Page mapped from the eCryptfs inode for the file; contains
+ * decrypted content that needs to be encrypted (to a temporary
+ * page; not in place) and written out to the lower file
+ *
+ * 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.
+ *
+ * Returns zero on success; negative on error
+ */
+int ecryptfs_encrypt_page(struct page *page)
+{
+ struct inode *ecryptfs_inode;
+ struct ecryptfs_crypt_stat *crypt_stat;
+ char *enc_extent_virt;
+ struct page *enc_extent_page = NULL;
+ loff_t extent_offset;
+ loff_t lower_offset;
+ int rc = 0;
+
+ ecryptfs_inode = page->mapping->host;
+ crypt_stat =
+ &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
+ BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+ enc_extent_page = alloc_page(GFP_USER);
+ if (!enc_extent_page) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Error allocating memory for "
+ "encrypted extent\n");
+ goto out;
+ }
+
+ for (extent_offset = 0;
+ extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+ extent_offset++) {
+ rc = crypt_extent(crypt_stat, enc_extent_page, page,
+ extent_offset, ENCRYPT);
+ if (rc) {
+ printk(KERN_ERR "%s: Error encrypting extent; "
+ "rc = [%d]\n", __func__, rc);
+ goto out;
+ }
+ }
+
+ lower_offset = lower_offset_for_page(crypt_stat, page);
+ enc_extent_virt = kmap(enc_extent_page);
+ rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
+ PAGE_CACHE_SIZE);
+ kunmap(enc_extent_page);
+ if (rc < 0) {
+ ecryptfs_printk(KERN_ERR,
+ "Error attempting to write lower page; rc = [%d]\n",
+ rc);
+ goto out;
+ }
+ rc = 0;
+out:
+ if (enc_extent_page) {
+ __free_page(enc_extent_page);
+ }
+ return rc;
+}
+
+/**
+ * ecryptfs_decrypt_page
+ * @page: Page mapped from the eCryptfs inode for the file; data read
+ * and decrypted from the lower file will be written into this
+ * page
+ *
+ * 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 page *page)
+{
+ struct inode *ecryptfs_inode;
+ struct ecryptfs_crypt_stat *crypt_stat;
+ char *page_virt;
+ unsigned long extent_offset;
+ loff_t lower_offset;
+ int rc = 0;
+
+ ecryptfs_inode = page->mapping->host;
+ crypt_stat =
+ &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
+ BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+
+ lower_offset = lower_offset_for_page(crypt_stat, page);
+ page_virt = kmap(page);
+ rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
+ ecryptfs_inode);
+ kunmap(page);
+ if (rc < 0) {
+ ecryptfs_printk(KERN_ERR,
+ "Error attempting to read lower page; rc = [%d]\n",
+ rc);
+ goto out;
+ }
+
+ for (extent_offset = 0;
+ extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+ extent_offset++) {
+ rc = crypt_extent(crypt_stat, page, page,
+ extent_offset, DECRYPT);
+ if (rc) {
+ printk(KERN_ERR "%s: Error encrypting extent; "
+ "rc = [%d]\n", __func__, rc);
+ goto out;
+ }
+ }
+out:
+ return rc;
+}
+
+#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
+
+/**
+ * ecryptfs_init_crypt_ctx
+ * @crypt_stat: Uninitialized 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;
+
+ ecryptfs_printk(KERN_DEBUG,
+ "Initializing cipher [%s]; strlen = [%d]; "
+ "key_size_bits = [%zd]\n",
+ crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
+ crypt_stat->key_size << 3);
+ mutex_lock(&crypt_stat->cs_tfm_mutex);
+ if (crypt_stat->tfm) {
+ rc = 0;
+ goto out_unlock;
+ }
+ rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
+ crypt_stat->cipher, "cbc");
+ if (rc)
+ goto out_unlock;
+ crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
+ if (IS_ERR(crypt_stat->tfm)) {
+ rc = PTR_ERR(crypt_stat->tfm);
+ crypt_stat->tfm = NULL;
+ ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
+ "Error initializing cipher [%s]\n",
+ full_alg_name);
+ goto out_free;
+ }
+ crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
+ rc = 0;
+out_free:
+ kfree(full_alg_name);
+out_unlock:
+ mutex_unlock(&crypt_stat->cs_tfm_mutex);
+ 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 (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+ crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+ else {
+ if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
+ crypt_stat->metadata_size =
+ ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+ else
+ crypt_stat->metadata_size = PAGE_CACHE_SIZE;
+ }
+}
+
+/**
+ * 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 (!(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);
+ 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);
+ 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
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
+ *
+ * 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;
+ if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
+ crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
+ if (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
+ crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
+ else if (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
+ crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
+ }
+}
+
+static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
+ struct ecryptfs_crypt_stat *crypt_stat,
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+ struct ecryptfs_global_auth_tok *global_auth_tok;
+ int rc = 0;
+
+ mutex_lock(&crypt_stat->keysig_list_mutex);
+ mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+
+ list_for_each_entry(global_auth_tok,
+ &mount_crypt_stat->global_auth_tok_list,
+ mount_crypt_stat_list) {
+ if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
+ continue;
+ rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
+ if (rc) {
+ printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
+ goto out;
+ }
+ }
+
+out:
+ mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+ mutex_unlock(&crypt_stat->keysig_list_mutex);
+ return rc;
+}
+
+/**
+ * ecryptfs_set_default_crypt_stat_vals
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
+ *
+ * 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;
+ 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_inode: The eCryptfs inode
+ *
+ * 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
+ */
+int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
+{
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+ &ecryptfs_superblock_to_private(
+ ecryptfs_inode->i_sb)->mount_crypt_stat;
+ int cipher_name_len;
+ int rc = 0;
+
+ ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
+ crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
+ ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+ mount_crypt_stat);
+ rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
+ mount_crypt_stat);
+ if (rc) {
+ printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
+ "to the inode key sigs; rc = [%d]\n", rc);
+ goto out;
+ }
+ 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);
+ 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);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_validate_marker - check for the ecryptfs marker
+ * @data: The data block in which to check
+ *
+ * Returns zero if marker found; -EINVAL if not found
+ */
+static int ecryptfs_validate_marker(char *data)
+{
+ u32 m_1, m_2;
+
+ m_1 = get_unaligned_be32(data);
+ m_2 = get_unaligned_be32(data + 4);
+ if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
+ return 0;
+ 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 -EINVAL;
+}
+
+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},
+ {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
+};
+
+/**
+ * ecryptfs_process_flags
+ * @crypt_stat: The cryptographic context
+ * @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;
+
+ flags = get_unaligned_be32(page_virt);
+ for (i = 0; i < ((sizeof(ecryptfs_flag_map)
+ / sizeof(struct ecryptfs_flag_map_elem))); i++)
+ if (flags & ecryptfs_flag_map[i].file_flag) {
+ crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
+ } else
+ 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);
+ put_unaligned_be32(m_1, page_virt);
+ page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
+ put_unaligned_be32(m_2, page_virt);
+ (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
+}
+
+void ecryptfs_write_crypt_stat_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 (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);
+ put_unaligned_be32(flags, page_virt);
+ (*written) = 4;
+}
+
+struct ecryptfs_cipher_code_str_map_elem {
+ char cipher_str[16];
+ u8 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
+ * @cipher_name: The string alias for the cipher
+ * @key_bytes: Length of key in bytes; used for AES code selection
+ *
+ * Returns zero on no match, or the cipher code on match
+ */
+u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
+{
+ int i;
+ u8 code = 0;
+ struct ecryptfs_cipher_code_str_map_elem *map =
+ ecryptfs_cipher_code_str_map;
+
+ if (strcmp(cipher_name, "aes") == 0) {
+ switch (key_bytes) {
+ 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(cipher_name, 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, u8 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;
+}
+
+int ecryptfs_read_and_validate_header_region(struct inode *inode)
+{
+ u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+ u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
+ int rc;
+
+ rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
+ inode);
+ if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+ return rc >= 0 ? -EINVAL : rc;
+ rc = ecryptfs_validate_marker(marker);
+ if (!rc)
+ ecryptfs_i_size_init(file_size, inode);
+ 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->extent_size;
+ num_header_extents_at_front =
+ (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
+ put_unaligned_be32(header_extent_size, virt);
+ virt += 4;
+ put_unaligned_be16(num_header_extents_at_front, virt);
+ (*written) = 6;
+}
+
+struct kmem_cache *ecryptfs_header_cache;
+
+/**
+ * ecryptfs_write_headers_virt
+ * @page_virt: The virtual address to write the headers to
+ * @max: The size of memory allocated at page_virt
+ * @size: Set to the number of bytes written by this function
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The 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 max,
+ 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;
+ ecryptfs_write_crypt_stat_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,
+ max - 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 inode *ecryptfs_inode,
+ char *virt, size_t virt_len)
+{
+ int rc;
+
+ rc = ecryptfs_write_lower(ecryptfs_inode, virt,
+ 0, virt_len);
+ if (rc < 0)
+ printk(KERN_ERR "%s: Error attempting to write header "
+ "information to lower file; rc = [%d]\n", __func__, rc);
+ else
+ rc = 0;
+ return rc;
+}
+
+static int
+ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
+ char *page_virt, size_t size)
+{
+ int rc;
+
+ rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
+ size, 0);
+ return rc;
+}
+
+static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
+ unsigned int order)
+{
+ struct page *page;
+
+ page = alloc_pages(gfp_mask | __GFP_ZERO, order);
+ if (page)
+ return (unsigned long) page_address(page);
+ return 0;
+}
+
+/**
+ * ecryptfs_write_metadata
+ * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
+ * @ecryptfs_inode: The newly created eCryptfs inode
+ *
+ * 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 inode *ecryptfs_inode)
+{
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+ unsigned int order;
+ char *virt;
+ size_t virt_len;
+ size_t size = 0;
+ int rc = 0;
+
+ if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+ if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
+ printk(KERN_ERR "Key is invalid; bailing out\n");
+ rc = -EINVAL;
+ goto out;
+ }
+ } else {
+ printk(KERN_WARNING "%s: Encrypted flag not set\n",
+ __func__);
+ rc = -EINVAL;
+ goto out;
+ }
+ virt_len = crypt_stat->metadata_size;
+ order = get_order(virt_len);
+ /* Released in this function */
+ virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
+ if (!virt) {
+ printk(KERN_ERR "%s: Out of memory\n", __func__);
+ rc = -ENOMEM;
+ goto out;
+ }
+ /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
+ rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
+ ecryptfs_dentry);
+ if (unlikely(rc)) {
+ printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
+ __func__, rc);
+ goto out_free;
+ }
+ if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+ rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
+ size);
+ else
+ rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
+ virt_len);
+ if (rc) {
+ printk(KERN_ERR "%s: Error writing metadata out to lower file; "
+ "rc = [%d]\n", __func__, rc);
+ goto out_free;
+ }
+out_free:
+ free_pages((unsigned long)virt, order);
+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;
+
+ header_extent_size = get_unaligned_be32(virt);
+ virt += sizeof(__be32);
+ num_header_extents_at_front = get_unaligned_be16(virt);
+ crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
+ * (size_t)header_extent_size));
+ (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
+ if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
+ && (crypt_stat->metadata_size
+ < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
+ rc = -EINVAL;
+ printk(KERN_WARNING "Invalid header size: [%zd]\n",
+ crypt_stat->metadata_size);
+ }
+ return rc;
+}
+
+/**
+ * set_default_header_data
+ * @crypt_stat: The cryptographic context
+ *
+ * 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->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+}
+
+void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
+{
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+ struct ecryptfs_crypt_stat *crypt_stat;
+ u64 file_size;
+
+ crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+ mount_crypt_stat =
+ &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
+ if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
+ file_size = i_size_read(ecryptfs_inode_to_lower(inode));
+ if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+ file_size += crypt_stat->metadata_size;
+ } else
+ file_size = get_unaligned_be64(page_virt);
+ i_size_write(inode, (loff_t)file_size);
+ crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
+}
+
+/**
+ * ecryptfs_read_headers_virt
+ * @page_virt: The virtual address into which to read the headers
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The eCryptfs dentry
+ * @validate_header_size: Whether to validate the header size while reading
+ *
+ * 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 = ecryptfs_validate_marker(page_virt + offset);
+ if (rc)
+ goto out;
+ if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
+ ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
+ 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
+ * @page_virt: The vitual address into which to read the xattr data
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Attempts to read the crypto metadata from the extended attribute
+ * region of the lower file.
+ *
+ * Returns zero on success; non-zero on error
+ */
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
+{
+ struct dentry *lower_dentry =
+ ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
+ ssize_t size;
+ int rc = 0;
+
+ size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
+ page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+ if (size < 0) {
+ if (unlikely(ecryptfs_verbosity > 0))
+ printk(KERN_INFO "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(struct dentry *dentry,
+ struct inode *inode)
+{
+ u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+ u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
+ int rc;
+
+ rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
+ ECRYPTFS_XATTR_NAME, file_size,
+ ECRYPTFS_SIZE_AND_MARKER_BYTES);
+ if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+ return rc >= 0 ? -EINVAL : rc;
+ rc = ecryptfs_validate_marker(marker);
+ if (!rc)
+ ecryptfs_i_size_init(file_size, inode);
+ 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)
+{
+ int rc;
+ char *page_virt;
+ struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(ecryptfs_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, GFP_USER);
+ if (!page_virt) {
+ rc = -ENOMEM;
+ printk(KERN_ERR "%s: Unable to allocate page_virt\n",
+ __func__);
+ goto out;
+ }
+ rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
+ ecryptfs_inode);
+ if (rc >= 0)
+ rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+ ecryptfs_dentry,
+ ECRYPTFS_VALIDATE_HEADER_SIZE);
+ if (rc) {
+ /* metadata is not in the file header, so try xattrs */
+ memset(page_virt, 0, PAGE_CACHE_SIZE);
+ rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
+ if (rc) {
+ printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+ "file header region or xattr region, inode %lu\n",
+ ecryptfs_inode->i_ino);
+ 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, inode %lu\n",
+ ecryptfs_inode->i_ino);
+ 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, inode %lu\n",
+ ecryptfs_inode->i_ino);
+ rc = -EINVAL;
+ }
+ }
+out:
+ if (page_virt) {
+ memset(page_virt, 0, PAGE_CACHE_SIZE);
+ kmem_cache_free(ecryptfs_header_cache, page_virt);
+ }
+ return rc;
+}
+
+/**
+ * ecryptfs_encrypt_filename - encrypt filename
+ *
+ * CBC-encrypts the filename. We do not want to encrypt the same
+ * filename with the same key and IV, which may happen with hard
+ * links, so we prepend random bits to each filename.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
+ struct ecryptfs_crypt_stat *crypt_stat,
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+ int rc = 0;
+
+ filename->encrypted_filename = NULL;
+ filename->encrypted_filename_size = 0;
+ if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
+ || (mount_crypt_stat && (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
+ size_t packet_size;
+ size_t remaining_bytes;
+
+ rc = ecryptfs_write_tag_70_packet(
+ NULL, NULL,
+ &filename->encrypted_filename_size,
+ mount_crypt_stat, NULL,
+ filename->filename_size);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to get packet "
+ "size for tag 72; rc = [%d]\n", __func__,
+ rc);
+ filename->encrypted_filename_size = 0;
+ goto out;
+ }
+ filename->encrypted_filename =
+ kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
+ if (!filename->encrypted_filename) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to kmalloc [%zd] bytes\n", __func__,
+ filename->encrypted_filename_size);
+ rc = -ENOMEM;
+ goto out;
+ }
+ remaining_bytes = filename->encrypted_filename_size;
+ rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
+ &remaining_bytes,
+ &packet_size,
+ mount_crypt_stat,
+ filename->filename,
+ filename->filename_size);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to generate "
+ "tag 70 packet; rc = [%d]\n", __func__,
+ rc);
+ kfree(filename->encrypted_filename);
+ filename->encrypted_filename = NULL;
+ filename->encrypted_filename_size = 0;
+ goto out;
+ }
+ filename->encrypted_filename_size = packet_size;
+ } else {
+ printk(KERN_ERR "%s: No support for requested filename "
+ "encryption method in this release\n", __func__);
+ rc = -EOPNOTSUPP;
+ goto out;
+ }
+out:
+ return rc;
+}
+
+static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
+ const char *name, size_t name_size)
+{
+ int rc = 0;
+
+ (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
+ if (!(*copied_name)) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ memcpy((void *)(*copied_name), (void *)name, name_size);
+ (*copied_name)[(name_size)] = '\0'; /* Only for convenience
+ * in printing out the
+ * string in debug
+ * messages */
+ (*copied_name_size) = name_size;
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_process_key_cipher - Perform key 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.
+ */
+static int
+ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
+ char *cipher_name, size_t *key_size)
+{
+ char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
+ char *full_alg_name = NULL;
+ 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);
+ if (IS_ERR(*key_tfm)) {
+ rc = PTR_ERR(*key_tfm);
+ printk(KERN_ERR "Unable to allocate crypto cipher with name "
+ "[%s]; rc = [%d]\n", full_alg_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, full_alg_name,
+ rc);
+ rc = -EINVAL;
+ goto out;
+ }
+out:
+ kfree(full_alg_name);
+ return rc;
+}
+
+struct kmem_cache *ecryptfs_key_tfm_cache;
+static struct list_head key_tfm_list;
+struct mutex key_tfm_list_mutex;
+
+int __init ecryptfs_init_crypto(void)
+{
+ mutex_init(&key_tfm_list_mutex);
+ INIT_LIST_HEAD(&key_tfm_list);
+ return 0;
+}
+
+/**
+ * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
+ *
+ * Called only at module unload time
+ */
+int ecryptfs_destroy_crypto(void)
+{
+ struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
+
+ mutex_lock(&key_tfm_list_mutex);
+ list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
+ key_tfm_list) {
+ list_del(&key_tfm->key_tfm_list);
+ if (key_tfm->key_tfm)
+ crypto_free_blkcipher(key_tfm->key_tfm);
+ kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
+ }
+ mutex_unlock(&key_tfm_list_mutex);
+ return 0;
+}
+
+int
+ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
+ size_t key_size)
+{
+ struct ecryptfs_key_tfm *tmp_tfm;
+ int rc = 0;
+
+ BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
+
+ tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
+ if (key_tfm != NULL)
+ (*key_tfm) = tmp_tfm;
+ if (!tmp_tfm) {
+ rc = -ENOMEM;
+ printk(KERN_ERR "Error attempting to allocate from "
+ "ecryptfs_key_tfm_cache\n");
+ goto out;
+ }
+ mutex_init(&tmp_tfm->key_tfm_mutex);
+ strncpy(tmp_tfm->cipher_name, cipher_name,
+ ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+ tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
+ tmp_tfm->key_size = key_size;
+ rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
+ tmp_tfm->cipher_name,
+ &tmp_tfm->key_size);
+ if (rc) {
+ printk(KERN_ERR "Error attempting to initialize key TFM "
+ "cipher with name = [%s]; rc = [%d]\n",
+ tmp_tfm->cipher_name, rc);
+ kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
+ if (key_tfm != NULL)
+ (*key_tfm) = NULL;
+ goto out;
+ }
+ list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Searches for cached key_tfm matching @cipher_name
+ * Must be called with &key_tfm_list_mutex held
+ * Returns 1 if found, with @key_tfm set
+ * Returns 0 if not found, with @key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+ struct ecryptfs_key_tfm *tmp_key_tfm;
+
+ BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
+
+ list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
+ if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
+ if (key_tfm)
+ (*key_tfm) = tmp_key_tfm;
+ return 1;
+ }
+ }
+ if (key_tfm)
+ (*key_tfm) = NULL;
+ return 0;
+}
+
+/**
+ * ecryptfs_get_tfm_and_mutex_for_cipher_name
+ *
+ * @tfm: set to cached tfm found, or new tfm created
+ * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
+ * @cipher_name: the name of the cipher to search for and/or add
+ *
+ * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
+ * Searches for cached item first, and creates new if not found.
+ * Returns 0 on success, non-zero if adding new cipher failed
+ */
+int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
+ struct mutex **tfm_mutex,
+ char *cipher_name)
+{
+ struct ecryptfs_key_tfm *key_tfm;
+ int rc = 0;
+
+ (*tfm) = NULL;
+ (*tfm_mutex) = NULL;
+
+ mutex_lock(&key_tfm_list_mutex);
+ if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
+ rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
+ if (rc) {
+ printk(KERN_ERR "Error adding new key_tfm to list; "
+ "rc = [%d]\n", rc);
+ goto out;
+ }
+ }
+ (*tfm) = key_tfm->key_tfm;
+ (*tfm_mutex) = &key_tfm->key_tfm_mutex;
+out:
+ mutex_unlock(&key_tfm_list_mutex);
+ return rc;
+}
+
+/* 64 characters forming a 6-bit target field */
+static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
+ "EFGHIJKLMNOPQRST"
+ "UVWXYZabcdefghij"
+ "klmnopqrstuvwxyz");
+
+/* We could either offset on every reverse map or just pad some 0x00's
+ * at the front here */
+static const unsigned char filename_rev_map[256] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
+ 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
+ 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
+ 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
+ 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
+ 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
+ 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
+ 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
+ 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
+ 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
+ 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
+};
+
+/**
+ * ecryptfs_encode_for_filename
+ * @dst: Destination location for encoded filename
+ * @dst_size: Size of the encoded filename in bytes
+ * @src: Source location for the filename to encode
+ * @src_size: Size of the source in bytes
+ */
+static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
+ unsigned char *src, size_t src_size)
+{
+ size_t num_blocks;
+ size_t block_num = 0;
+ size_t dst_offset = 0;
+ unsigned char last_block[3];
+
+ if (src_size == 0) {
+ (*dst_size) = 0;
+ goto out;
+ }
+ num_blocks = (src_size / 3);
+ if ((src_size % 3) == 0) {
+ memcpy(last_block, (&src[src_size - 3]), 3);
+ } else {
+ num_blocks++;
+ last_block[2] = 0x00;
+ switch (src_size % 3) {
+ case 1:
+ last_block[0] = src[src_size - 1];
+ last_block[1] = 0x00;
+ break;
+ case 2:
+ last_block[0] = src[src_size - 2];
+ last_block[1] = src[src_size - 1];
+ }
+ }
+ (*dst_size) = (num_blocks * 4);
+ if (!dst)
+ goto out;
+ while (block_num < num_blocks) {
+ unsigned char *src_block;
+ unsigned char dst_block[4];
+
+ if (block_num == (num_blocks - 1))
+ src_block = last_block;
+ else
+ src_block = &src[block_num * 3];
+ dst_block[0] = ((src_block[0] >> 2) & 0x3F);
+ dst_block[1] = (((src_block[0] << 4) & 0x30)
+ | ((src_block[1] >> 4) & 0x0F));
+ dst_block[2] = (((src_block[1] << 2) & 0x3C)
+ | ((src_block[2] >> 6) & 0x03));
+ dst_block[3] = (src_block[2] & 0x3F);
+ dst[dst_offset++] = portable_filename_chars[dst_block[0]];
+ dst[dst_offset++] = portable_filename_chars[dst_block[1]];
+ dst[dst_offset++] = portable_filename_chars[dst_block[2]];
+ dst[dst_offset++] = portable_filename_chars[dst_block[3]];
+ block_num++;
+ }
+out:
+ return;
+}
+
+static size_t ecryptfs_max_decoded_size(size_t encoded_size)
+{
+ /* Not exact; conservatively long. Every block of 4
+ * encoded characters decodes into a block of 3
+ * decoded characters. This segment of code provides
+ * the caller with the maximum amount of allocated
+ * space that @dst will need to point to in a
+ * subsequent call. */
+ return ((encoded_size + 1) * 3) / 4;
+}
+
+/**
+ * ecryptfs_decode_from_filename
+ * @dst: If NULL, this function only sets @dst_size and returns. If
+ * non-NULL, this function decodes the encoded octets in @src
+ * into the memory that @dst points to.
+ * @dst_size: Set to the size of the decoded string.
+ * @src: The encoded set of octets to decode.
+ * @src_size: The size of the encoded set of octets to decode.
+ */
+static void
+ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
+ const unsigned char *src, size_t src_size)
+{
+ u8 current_bit_offset = 0;
+ size_t src_byte_offset = 0;
+ size_t dst_byte_offset = 0;
+
+ if (dst == NULL) {
+ (*dst_size) = ecryptfs_max_decoded_size(src_size);
+ goto out;
+ }
+ while (src_byte_offset < src_size) {
+ unsigned char src_byte =
+ filename_rev_map[(int)src[src_byte_offset]];
+
+ switch (current_bit_offset) {
+ case 0:
+ dst[dst_byte_offset] = (src_byte << 2);
+ current_bit_offset = 6;
+ break;
+ case 6:
+ dst[dst_byte_offset++] |= (src_byte >> 4);
+ dst[dst_byte_offset] = ((src_byte & 0xF)
+ << 4);
+ current_bit_offset = 4;
+ break;
+ case 4:
+ dst[dst_byte_offset++] |= (src_byte >> 2);
+ dst[dst_byte_offset] = (src_byte << 6);
+ current_bit_offset = 2;
+ break;
+ case 2:
+ dst[dst_byte_offset++] |= (src_byte);
+ current_bit_offset = 0;
+ break;
+ }
+ src_byte_offset++;
+ }
+ (*dst_size) = dst_byte_offset;
+out:
+ return;
+}
+
+/**
+ * ecryptfs_encrypt_and_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.
+ *
+ * Returns zero on success; non-zero on otherwise
+ */
+int ecryptfs_encrypt_and_encode_filename(
+ char **encoded_name,
+ size_t *encoded_name_size,
+ struct ecryptfs_crypt_stat *crypt_stat,
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+ const char *name, size_t name_size)
+{
+ size_t encoded_name_no_prefix_size;
+ int rc = 0;
+
+ (*encoded_name) = NULL;
+ (*encoded_name_size) = 0;
+ if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
+ || (mount_crypt_stat && (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
+ struct ecryptfs_filename *filename;
+
+ filename = kzalloc(sizeof(*filename), GFP_KERNEL);
+ if (!filename) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to kzalloc [%zd] bytes\n", __func__,
+ sizeof(*filename));
+ rc = -ENOMEM;
+ goto out;
+ }
+ filename->filename = (char *)name;
+ filename->filename_size = name_size;
+ rc = ecryptfs_encrypt_filename(filename, crypt_stat,
+ mount_crypt_stat);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to encrypt "
+ "filename; rc = [%d]\n", __func__, rc);
+ kfree(filename);
+ goto out;
+ }
+ ecryptfs_encode_for_filename(
+ NULL, &encoded_name_no_prefix_size,
+ filename->encrypted_filename,
+ filename->encrypted_filename_size);
+ if ((crypt_stat && (crypt_stat->flags
+ & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
+ || (mount_crypt_stat
+ && (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
+ (*encoded_name_size) =
+ (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+ + encoded_name_no_prefix_size);
+ else
+ (*encoded_name_size) =
+ (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+ + encoded_name_no_prefix_size);
+ (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
+ if (!(*encoded_name)) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to kzalloc [%zd] bytes\n", __func__,
+ (*encoded_name_size));
+ rc = -ENOMEM;
+ kfree(filename->encrypted_filename);
+ kfree(filename);
+ goto out;
+ }
+ if ((crypt_stat && (crypt_stat->flags
+ & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
+ || (mount_crypt_stat
+ && (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
+ memcpy((*encoded_name),
+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
+ ecryptfs_encode_for_filename(
+ ((*encoded_name)
+ + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
+ &encoded_name_no_prefix_size,
+ filename->encrypted_filename,
+ filename->encrypted_filename_size);
+ (*encoded_name_size) =
+ (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+ + encoded_name_no_prefix_size);
+ (*encoded_name)[(*encoded_name_size)] = '\0';
+ } else {
+ rc = -EOPNOTSUPP;
+ }
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to encode "
+ "encrypted filename; rc = [%d]\n", __func__,
+ rc);
+ kfree((*encoded_name));
+ (*encoded_name) = NULL;
+ (*encoded_name_size) = 0;
+ }
+ kfree(filename->encrypted_filename);
+ kfree(filename);
+ } else {
+ rc = ecryptfs_copy_filename(encoded_name,
+ encoded_name_size,
+ name, name_size);
+ }
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
+ * @plaintext_name: The plaintext name
+ * @plaintext_name_size: The plaintext name size
+ * @ecryptfs_dir_dentry: eCryptfs directory dentry
+ * @name: The filename in cipher text
+ * @name_size: The cipher text name size
+ *
+ * Decrypts and decodes the filename.
+ *
+ * Returns zero on error; non-zero otherwise
+ */
+int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
+ size_t *plaintext_name_size,
+ struct super_block *sb,
+ const char *name, size_t name_size)
+{
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+ &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
+ char *decoded_name;
+ size_t decoded_name_size;
+ size_t packet_size;
+ int rc = 0;
+
+ if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+ && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+ && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
+ && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
+ const char *orig_name = name;
+ size_t orig_name_size = name_size;
+
+ name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+ name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+ ecryptfs_decode_from_filename(NULL, &decoded_name_size,
+ name, name_size);
+ decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
+ if (!decoded_name) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to kmalloc [%zd] bytes\n", __func__,
+ decoded_name_size);
+ rc = -ENOMEM;
+ goto out;
+ }
+ ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
+ name, name_size);
+ rc = ecryptfs_parse_tag_70_packet(plaintext_name,
+ plaintext_name_size,
+ &packet_size,
+ mount_crypt_stat,
+ decoded_name,
+ decoded_name_size);
+ if (rc) {
+ printk(KERN_INFO "%s: Could not parse tag 70 packet "
+ "from filename; copying through filename "
+ "as-is\n", __func__);
+ rc = ecryptfs_copy_filename(plaintext_name,
+ plaintext_name_size,
+ orig_name, orig_name_size);
+ goto out_free;
+ }
+ } else {
+ rc = ecryptfs_copy_filename(plaintext_name,
+ plaintext_name_size,
+ name, name_size);
+ goto out;
+ }
+out_free:
+ kfree(decoded_name);
+out:
+ return rc;
+}
+
+#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
+
+int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+ struct blkcipher_desc desc;
+ struct mutex *tfm_mutex;
+ size_t cipher_blocksize;
+ int rc;
+
+ if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
+ (*namelen) = lower_namelen;
+ return 0;
+ }
+
+ rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
+ mount_crypt_stat->global_default_fn_cipher_name);
+ if (unlikely(rc)) {
+ (*namelen) = 0;
+ return rc;
+ }
+
+ mutex_lock(tfm_mutex);
+ cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
+ mutex_unlock(tfm_mutex);
+
+ /* Return an exact amount for the common cases */
+ if (lower_namelen == NAME_MAX
+ && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
+ (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
+ return 0;
+ }
+
+ /* Return a safe estimate for the uncommon cases */
+ (*namelen) = lower_namelen;
+ (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+ /* Since this is the max decoded size, subtract 1 "decoded block" len */
+ (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
+ (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
+ (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
+ /* Worst case is that the filename is padded nearly a full block size */
+ (*namelen) -= cipher_blocksize - 1;
+
+ if ((*namelen) < 0)
+ (*namelen) = 0;
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff