diff options
Diffstat (limited to 'kernel/fs/ecryptfs/keystore.c')
| -rw-r--r-- | kernel/fs/ecryptfs/keystore.c | 2529 |
1 files changed, 2529 insertions, 0 deletions
diff --git a/kernel/fs/ecryptfs/keystore.c b/kernel/fs/ecryptfs/keystore.c new file mode 100644 index 000000000..6bd67e201 --- /dev/null +++ b/kernel/fs/ecryptfs/keystore.c @@ -0,0 +1,2529 @@ +/** + * eCryptfs: Linux filesystem encryption layer + * In-kernel key management code. Includes functions to parse and + * write authentication token-related packets with the underlying + * file. + * + * Copyright (C) 2004-2006 International Business Machines Corp. + * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> + * Michael C. Thompson <mcthomps@us.ibm.com> + * Trevor S. Highland <trevor.highland@gmail.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/string.h> +#include <linux/pagemap.h> +#include <linux/key.h> +#include <linux/random.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include "ecryptfs_kernel.h" + +/** + * request_key returned an error instead of a valid key address; + * determine the type of error, make appropriate log entries, and + * return an error code. + */ +static int process_request_key_err(long err_code) +{ + int rc = 0; + + switch (err_code) { + case -ENOKEY: + ecryptfs_printk(KERN_WARNING, "No key\n"); + rc = -ENOENT; + break; + case -EKEYEXPIRED: + ecryptfs_printk(KERN_WARNING, "Key expired\n"); + rc = -ETIME; + break; + case -EKEYREVOKED: + ecryptfs_printk(KERN_WARNING, "Key revoked\n"); + rc = -EINVAL; + break; + default: + ecryptfs_printk(KERN_WARNING, "Unknown error code: " + "[0x%.16lx]\n", err_code); + rc = -EINVAL; + } + return rc; +} + +static int process_find_global_auth_tok_for_sig_err(int err_code) +{ + int rc = err_code; + + switch (err_code) { + case -ENOENT: + ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); + break; + case -EINVAL: + ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); + break; + default: + rc = process_request_key_err(err_code); + break; + } + return rc; +} + +/** + * ecryptfs_parse_packet_length + * @data: Pointer to memory containing length at offset + * @size: This function writes the decoded size to this memory + * address; zero on error + * @length_size: The number of bytes occupied by the encoded length + * + * Returns zero on success; non-zero on error + */ +int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, + size_t *length_size) +{ + int rc = 0; + + (*length_size) = 0; + (*size) = 0; + if (data[0] < 192) { + /* One-byte length */ + (*size) = data[0]; + (*length_size) = 1; + } else if (data[0] < 224) { + /* Two-byte length */ + (*size) = (data[0] - 192) * 256; + (*size) += data[1] + 192; + (*length_size) = 2; + } else if (data[0] == 255) { + /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ + ecryptfs_printk(KERN_ERR, "Five-byte packet length not " + "supported\n"); + rc = -EINVAL; + goto out; + } else { + ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); + rc = -EINVAL; + goto out; + } +out: + return rc; +} + +/** + * ecryptfs_write_packet_length + * @dest: The byte array target into which to write the length. Must + * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. + * @size: The length to write. + * @packet_size_length: The number of bytes used to encode the packet + * length is written to this address. + * + * Returns zero on success; non-zero on error. + */ +int ecryptfs_write_packet_length(char *dest, size_t size, + size_t *packet_size_length) +{ + int rc = 0; + + if (size < 192) { + dest[0] = size; + (*packet_size_length) = 1; + } else if (size < 65536) { + dest[0] = (((size - 192) / 256) + 192); + dest[1] = ((size - 192) % 256); + (*packet_size_length) = 2; + } else { + /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ + rc = -EINVAL; + ecryptfs_printk(KERN_WARNING, + "Unsupported packet size: [%zd]\n", size); + } + return rc; +} + +static int +write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, + char **packet, size_t *packet_len) +{ + size_t i = 0; + size_t data_len; + size_t packet_size_len; + char *message; + int rc; + + /* + * ***** TAG 64 Packet Format ***** + * | Content Type | 1 byte | + * | Key Identifier Size | 1 or 2 bytes | + * | Key Identifier | arbitrary | + * | Encrypted File Encryption Key Size | 1 or 2 bytes | + * | Encrypted File Encryption Key | arbitrary | + */ + data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + + session_key->encrypted_key_size); + *packet = kmalloc(data_len, GFP_KERNEL); + message = *packet; + if (!message) { + ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); + rc = -ENOMEM; + goto out; + } + message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; + rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, + &packet_size_len); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " + "header; cannot generate packet length\n"); + goto out; + } + i += packet_size_len; + memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); + i += ECRYPTFS_SIG_SIZE_HEX; + rc = ecryptfs_write_packet_length(&message[i], + session_key->encrypted_key_size, + &packet_size_len); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " + "header; cannot generate packet length\n"); + goto out; + } + i += packet_size_len; + memcpy(&message[i], session_key->encrypted_key, + session_key->encrypted_key_size); + i += session_key->encrypted_key_size; + *packet_len = i; +out: + return rc; +} + +static int +parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, + struct ecryptfs_message *msg) +{ + size_t i = 0; + char *data; + size_t data_len; + size_t m_size; + size_t message_len; + u16 checksum = 0; + u16 expected_checksum = 0; + int rc; + + /* + * ***** TAG 65 Packet Format ***** + * | Content Type | 1 byte | + * | Status Indicator | 1 byte | + * | File Encryption Key Size | 1 or 2 bytes | + * | File Encryption Key | arbitrary | + */ + message_len = msg->data_len; + data = msg->data; + if (message_len < 4) { + rc = -EIO; + goto out; + } + if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { + ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); + rc = -EIO; + goto out; + } + if (data[i++]) { + ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " + "[%d]\n", data[i-1]); + rc = -EIO; + goto out; + } + rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); + if (rc) { + ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " + "rc = [%d]\n", rc); + goto out; + } + i += data_len; + if (message_len < (i + m_size)) { + ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " + "is shorter than expected\n"); + rc = -EIO; + goto out; + } + if (m_size < 3) { + ecryptfs_printk(KERN_ERR, + "The decrypted key is not long enough to " + "include a cipher code and checksum\n"); + rc = -EIO; + goto out; + } + *cipher_code = data[i++]; + /* The decrypted key includes 1 byte cipher code and 2 byte checksum */ + session_key->decrypted_key_size = m_size - 3; + if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { + ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " + "the maximum key size [%d]\n", + session_key->decrypted_key_size, + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); + rc = -EIO; + goto out; + } + memcpy(session_key->decrypted_key, &data[i], + session_key->decrypted_key_size); + i += session_key->decrypted_key_size; + expected_checksum += (unsigned char)(data[i++]) << 8; + expected_checksum += (unsigned char)(data[i++]); + for (i = 0; i < session_key->decrypted_key_size; i++) + checksum += session_key->decrypted_key[i]; + if (expected_checksum != checksum) { + ecryptfs_printk(KERN_ERR, "Invalid checksum for file " + "encryption key; expected [%x]; calculated " + "[%x]\n", expected_checksum, checksum); + rc = -EIO; + } +out: + return rc; +} + + +static int +write_tag_66_packet(char *signature, u8 cipher_code, + struct ecryptfs_crypt_stat *crypt_stat, char **packet, + size_t *packet_len) +{ + size_t i = 0; + size_t j; + size_t data_len; + size_t checksum = 0; + size_t packet_size_len; + char *message; + int rc; + + /* + * ***** TAG 66 Packet Format ***** + * | Content Type | 1 byte | + * | Key Identifier Size | 1 or 2 bytes | + * | Key Identifier | arbitrary | + * | File Encryption Key Size | 1 or 2 bytes | + * | File Encryption Key | arbitrary | + */ + data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); + *packet = kmalloc(data_len, GFP_KERNEL); + message = *packet; + if (!message) { + ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); + rc = -ENOMEM; + goto out; + } + message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; + rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, + &packet_size_len); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " + "header; cannot generate packet length\n"); + goto out; + } + i += packet_size_len; + memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); + i += ECRYPTFS_SIG_SIZE_HEX; + /* The encrypted key includes 1 byte cipher code and 2 byte checksum */ + rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, + &packet_size_len); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " + "header; cannot generate packet length\n"); + goto out; + } + i += packet_size_len; + message[i++] = cipher_code; + memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); + i += crypt_stat->key_size; + for (j = 0; j < crypt_stat->key_size; j++) + checksum += crypt_stat->key[j]; + message[i++] = (checksum / 256) % 256; + message[i++] = (checksum % 256); + *packet_len = i; +out: + return rc; +} + +static int +parse_tag_67_packet(struct ecryptfs_key_record *key_rec, + struct ecryptfs_message *msg) +{ + size_t i = 0; + char *data; + size_t data_len; + size_t message_len; + int rc; + + /* + * ***** TAG 65 Packet Format ***** + * | Content Type | 1 byte | + * | Status Indicator | 1 byte | + * | Encrypted File Encryption Key Size | 1 or 2 bytes | + * | Encrypted File Encryption Key | arbitrary | + */ + message_len = msg->data_len; + data = msg->data; + /* verify that everything through the encrypted FEK size is present */ + if (message_len < 4) { + rc = -EIO; + printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " + "message length is [%d]\n", __func__, message_len, 4); + goto out; + } + if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { + rc = -EIO; + printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", + __func__); + goto out; + } + if (data[i++]) { + rc = -EIO; + printk(KERN_ERR "%s: Status indicator has non zero " + "value [%d]\n", __func__, data[i-1]); + + goto out; + } + rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, + &data_len); + if (rc) { + ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " + "rc = [%d]\n", rc); + goto out; + } + i += data_len; + if (message_len < (i + key_rec->enc_key_size)) { + rc = -EIO; + printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", + __func__, message_len, (i + key_rec->enc_key_size)); + goto out; + } + if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { + rc = -EIO; + printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " + "the maximum key size [%d]\n", __func__, + key_rec->enc_key_size, + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); + goto out; + } + memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); +out: + return rc; +} + +/** + * ecryptfs_verify_version + * @version: The version number to confirm + * + * Returns zero on good version; non-zero otherwise + */ +static int ecryptfs_verify_version(u16 version) +{ + int rc = 0; + unsigned char major; + unsigned char minor; + + major = ((version >> 8) & 0xFF); + minor = (version & 0xFF); + if (major != ECRYPTFS_VERSION_MAJOR) { + ecryptfs_printk(KERN_ERR, "Major version number mismatch. " + "Expected [%d]; got [%d]\n", + ECRYPTFS_VERSION_MAJOR, major); + rc = -EINVAL; + goto out; + } + if (minor != ECRYPTFS_VERSION_MINOR) { + ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " + "Expected [%d]; got [%d]\n", + ECRYPTFS_VERSION_MINOR, minor); + rc = -EINVAL; + goto out; + } +out: + return rc; +} + +/** + * ecryptfs_verify_auth_tok_from_key + * @auth_tok_key: key containing the authentication token + * @auth_tok: authentication token + * + * Returns zero on valid auth tok; -EINVAL otherwise + */ +static int +ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, + struct ecryptfs_auth_tok **auth_tok) +{ + int rc = 0; + + (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); + if (ecryptfs_verify_version((*auth_tok)->version)) { + printk(KERN_ERR "Data structure version mismatch. Userspace " + "tools must match eCryptfs kernel module with major " + "version [%d] and minor version [%d]\n", + ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); + rc = -EINVAL; + goto out; + } + if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD + && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { + printk(KERN_ERR "Invalid auth_tok structure " + "returned from key query\n"); + rc = -EINVAL; + goto out; + } +out: + return rc; +} + +static int +ecryptfs_find_global_auth_tok_for_sig( + struct key **auth_tok_key, + struct ecryptfs_auth_tok **auth_tok, + struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) +{ + struct ecryptfs_global_auth_tok *walker; + int rc = 0; + + (*auth_tok_key) = NULL; + (*auth_tok) = NULL; + mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); + list_for_each_entry(walker, + &mount_crypt_stat->global_auth_tok_list, + mount_crypt_stat_list) { + if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) + continue; + + if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { + rc = -EINVAL; + goto out; + } + + rc = key_validate(walker->global_auth_tok_key); + if (rc) { + if (rc == -EKEYEXPIRED) + goto out; + goto out_invalid_auth_tok; + } + + down_write(&(walker->global_auth_tok_key->sem)); + rc = ecryptfs_verify_auth_tok_from_key( + walker->global_auth_tok_key, auth_tok); + if (rc) + goto out_invalid_auth_tok_unlock; + + (*auth_tok_key) = walker->global_auth_tok_key; + key_get(*auth_tok_key); + goto out; + } + rc = -ENOENT; + goto out; +out_invalid_auth_tok_unlock: + up_write(&(walker->global_auth_tok_key->sem)); +out_invalid_auth_tok: + printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); + walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; + key_put(walker->global_auth_tok_key); + walker->global_auth_tok_key = NULL; +out: + mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); + return rc; +} + +/** + * ecryptfs_find_auth_tok_for_sig + * @auth_tok: Set to the matching auth_tok; NULL if not found + * @crypt_stat: inode crypt_stat crypto context + * @sig: Sig of auth_tok to find + * + * For now, this function simply looks at the registered auth_tok's + * linked off the mount_crypt_stat, so all the auth_toks that can be + * used must be registered at mount time. This function could + * potentially try a lot harder to find auth_tok's (e.g., by calling + * out to ecryptfsd to dynamically retrieve an auth_tok object) so + * that static registration of auth_tok's will no longer be necessary. + * + * Returns zero on no error; non-zero on error + */ +static int +ecryptfs_find_auth_tok_for_sig( + struct key **auth_tok_key, + struct ecryptfs_auth_tok **auth_tok, + struct ecryptfs_mount_crypt_stat *mount_crypt_stat, + char *sig) +{ + int rc = 0; + + rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, + mount_crypt_stat, sig); + if (rc == -ENOENT) { + /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the + * mount_crypt_stat structure, we prevent to use auth toks that + * are not inserted through the ecryptfs_add_global_auth_tok + * function. + */ + if (mount_crypt_stat->flags + & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) + return -EINVAL; + + rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, + sig); + } + return rc; +} + +/** + * write_tag_70_packet can gobble a lot of stack space. We stuff most + * of the function's parameters in a kmalloc'd struct to help reduce + * eCryptfs' overall stack usage. + */ +struct ecryptfs_write_tag_70_packet_silly_stack { + u8 cipher_code; + size_t max_packet_size; + size_t packet_size_len; + size_t block_aligned_filename_size; + size_t block_size; + size_t i; + size_t j; + size_t num_rand_bytes; + struct mutex *tfm_mutex; + char *block_aligned_filename; + struct ecryptfs_auth_tok *auth_tok; + struct scatterlist src_sg[2]; + struct scatterlist dst_sg[2]; + struct blkcipher_desc desc; + char iv[ECRYPTFS_MAX_IV_BYTES]; + char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; + char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; + struct hash_desc hash_desc; + struct scatterlist hash_sg; +}; + +/** + * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK + * @filename: NULL-terminated filename string + * + * This is the simplest mechanism for achieving filename encryption in + * eCryptfs. It encrypts the given filename with the mount-wide + * filename encryption key (FNEK) and stores it in a packet to @dest, + * which the callee will encode and write directly into the dentry + * name. + */ +int +ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, + size_t *packet_size, + struct ecryptfs_mount_crypt_stat *mount_crypt_stat, + char *filename, size_t filename_size) +{ + struct ecryptfs_write_tag_70_packet_silly_stack *s; + struct key *auth_tok_key = NULL; + int rc = 0; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) { + printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " + "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); + rc = -ENOMEM; + goto out; + } + s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + (*packet_size) = 0; + rc = ecryptfs_find_auth_tok_for_sig( + &auth_tok_key, + &s->auth_tok, mount_crypt_stat, + mount_crypt_stat->global_default_fnek_sig); + if (rc) { + printk(KERN_ERR "%s: Error attempting to find auth tok for " + "fnek sig [%s]; rc = [%d]\n", __func__, + mount_crypt_stat->global_default_fnek_sig, rc); + goto out; + } + rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( + &s->desc.tfm, + &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); + if (unlikely(rc)) { + printk(KERN_ERR "Internal error whilst attempting to get " + "tfm and mutex for cipher name [%s]; rc = [%d]\n", + mount_crypt_stat->global_default_fn_cipher_name, rc); + goto out; + } + mutex_lock(s->tfm_mutex); + s->block_size = crypto_blkcipher_blocksize(s->desc.tfm); + /* Plus one for the \0 separator between the random prefix + * and the plaintext filename */ + s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); + s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); + if ((s->block_aligned_filename_size % s->block_size) != 0) { + s->num_rand_bytes += (s->block_size + - (s->block_aligned_filename_size + % s->block_size)); + s->block_aligned_filename_size = (s->num_rand_bytes + + filename_size); + } + /* Octet 0: Tag 70 identifier + * Octets 1-N1: Tag 70 packet size (includes cipher identifier + * and block-aligned encrypted filename size) + * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) + * Octet N2-N3: Cipher identifier (1 octet) + * Octets N3-N4: Block-aligned encrypted filename + * - Consists of a minimum number of random characters, a \0 + * separator, and then the filename */ + s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE + + s->block_aligned_filename_size); + if (dest == NULL) { + (*packet_size) = s->max_packet_size; + goto out_unlock; + } + if (s->max_packet_size > (*remaining_bytes)) { + printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " + "[%zd] available\n", __func__, s->max_packet_size, + (*remaining_bytes)); + rc = -EINVAL; + goto out_unlock; + } + s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, + GFP_KERNEL); + if (!s->block_aligned_filename) { + printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " + "kzalloc [%zd] bytes\n", __func__, + s->block_aligned_filename_size); + rc = -ENOMEM; + goto out_unlock; + } + s->i = 0; + dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; + rc = ecryptfs_write_packet_length(&dest[s->i], + (ECRYPTFS_SIG_SIZE + + 1 /* Cipher code */ + + s->block_aligned_filename_size), + &s->packet_size_len); + if (rc) { + printk(KERN_ERR "%s: Error generating tag 70 packet " + "header; cannot generate packet length; rc = [%d]\n", + __func__, rc); + goto out_free_unlock; + } + s->i += s->packet_size_len; + ecryptfs_from_hex(&dest[s->i], + mount_crypt_stat->global_default_fnek_sig, + ECRYPTFS_SIG_SIZE); + s->i += ECRYPTFS_SIG_SIZE; + s->cipher_code = ecryptfs_code_for_cipher_string( + mount_crypt_stat->global_default_fn_cipher_name, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + if (s->cipher_code == 0) { + printk(KERN_WARNING "%s: Unable to generate code for " + "cipher [%s] with key bytes [%zd]\n", __func__, + mount_crypt_stat->global_default_fn_cipher_name, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + rc = -EINVAL; + goto out_free_unlock; + } + dest[s->i++] = s->cipher_code; + /* TODO: Support other key modules than passphrase for + * filename encryption */ + if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { + rc = -EOPNOTSUPP; + printk(KERN_INFO "%s: Filename encryption only supports " + "password tokens\n", __func__); + goto out_free_unlock; + } + sg_init_one( + &s->hash_sg, + (u8 *)s->auth_tok->token.password.session_key_encryption_key, + s->auth_tok->token.password.session_key_encryption_key_bytes); + s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(s->hash_desc.tfm)) { + rc = PTR_ERR(s->hash_desc.tfm); + printk(KERN_ERR "%s: Error attempting to " + "allocate hash crypto context; rc = [%d]\n", + __func__, rc); + goto out_free_unlock; + } + rc = crypto_hash_init(&s->hash_desc); + if (rc) { + printk(KERN_ERR + "%s: Error initializing crypto hash; rc = [%d]\n", + __func__, rc); + goto out_release_free_unlock; + } + rc = crypto_hash_update( + &s->hash_desc, &s->hash_sg, + s->auth_tok->token.password.session_key_encryption_key_bytes); + if (rc) { + printk(KERN_ERR + "%s: Error updating crypto hash; rc = [%d]\n", + __func__, rc); + goto out_release_free_unlock; + } + rc = crypto_hash_final(&s->hash_desc, s->hash); + if (rc) { + printk(KERN_ERR + "%s: Error finalizing crypto hash; rc = [%d]\n", + __func__, rc); + goto out_release_free_unlock; + } + for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { + s->block_aligned_filename[s->j] = + s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; + if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) + == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { + sg_init_one(&s->hash_sg, (u8 *)s->hash, + ECRYPTFS_TAG_70_DIGEST_SIZE); + rc = crypto_hash_init(&s->hash_desc); + if (rc) { + printk(KERN_ERR + "%s: Error initializing crypto hash; " + "rc = [%d]\n", __func__, rc); + goto out_release_free_unlock; + } + rc = crypto_hash_update(&s->hash_desc, &s->hash_sg, + ECRYPTFS_TAG_70_DIGEST_SIZE); + if (rc) { + printk(KERN_ERR + "%s: Error updating crypto hash; " + "rc = [%d]\n", __func__, rc); + goto out_release_free_unlock; + } + rc = crypto_hash_final(&s->hash_desc, s->tmp_hash); + if (rc) { + printk(KERN_ERR + "%s: Error finalizing crypto hash; " + "rc = [%d]\n", __func__, rc); + goto out_release_free_unlock; + } + memcpy(s->hash, s->tmp_hash, + ECRYPTFS_TAG_70_DIGEST_SIZE); + } + if (s->block_aligned_filename[s->j] == '\0') + s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; + } + memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, + filename_size); + rc = virt_to_scatterlist(s->block_aligned_filename, + s->block_aligned_filename_size, s->src_sg, 2); + if (rc < 1) { + printk(KERN_ERR "%s: Internal error whilst attempting to " + "convert filename memory to scatterlist; rc = [%d]. " + "block_aligned_filename_size = [%zd]\n", __func__, rc, + s->block_aligned_filename_size); + goto out_release_free_unlock; + } + rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, + s->dst_sg, 2); + if (rc < 1) { + printk(KERN_ERR "%s: Internal error whilst attempting to " + "convert encrypted filename memory to scatterlist; " + "rc = [%d]. block_aligned_filename_size = [%zd]\n", + __func__, rc, s->block_aligned_filename_size); + goto out_release_free_unlock; + } + /* The characters in the first block effectively do the job + * of the IV here, so we just use 0's for the IV. Note the + * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + * >= ECRYPTFS_MAX_IV_BYTES. */ + memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); + s->desc.info = s->iv; + rc = crypto_blkcipher_setkey( + s->desc.tfm, + s->auth_tok->token.password.session_key_encryption_key, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + if (rc < 0) { + printk(KERN_ERR "%s: Error setting key for crypto context; " + "rc = [%d]. s->auth_tok->token.password.session_key_" + "encryption_key = [0x%p]; mount_crypt_stat->" + "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, + rc, + s->auth_tok->token.password.session_key_encryption_key, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + goto out_release_free_unlock; + } + rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg, + s->block_aligned_filename_size); + if (rc) { + printk(KERN_ERR "%s: Error attempting to encrypt filename; " + "rc = [%d]\n", __func__, rc); + goto out_release_free_unlock; + } + s->i += s->block_aligned_filename_size; + (*packet_size) = s->i; + (*remaining_bytes) -= (*packet_size); +out_release_free_unlock: + crypto_free_hash(s->hash_desc.tfm); +out_free_unlock: + kzfree(s->block_aligned_filename); +out_unlock: + mutex_unlock(s->tfm_mutex); +out: + if (auth_tok_key) { + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + } + kfree(s); + return rc; +} + +struct ecryptfs_parse_tag_70_packet_silly_stack { + u8 cipher_code; + size_t max_packet_size; + size_t packet_size_len; + size_t parsed_tag_70_packet_size; + size_t block_aligned_filename_size; + size_t block_size; + size_t i; + struct mutex *tfm_mutex; + char *decrypted_filename; + struct ecryptfs_auth_tok *auth_tok; + struct scatterlist src_sg[2]; + struct scatterlist dst_sg[2]; + struct blkcipher_desc desc; + char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; + char iv[ECRYPTFS_MAX_IV_BYTES]; + char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; +}; + +/** + * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet + * @filename: This function kmalloc's the memory for the filename + * @filename_size: This function sets this to the amount of memory + * kmalloc'd for the filename + * @packet_size: This function sets this to the the number of octets + * in the packet parsed + * @mount_crypt_stat: The mount-wide cryptographic context + * @data: The memory location containing the start of the tag 70 + * packet + * @max_packet_size: The maximum legal size of the packet to be parsed + * from @data + * + * Returns zero on success; non-zero otherwise + */ +int +ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, + size_t *packet_size, + struct ecryptfs_mount_crypt_stat *mount_crypt_stat, + char *data, size_t max_packet_size) +{ + struct ecryptfs_parse_tag_70_packet_silly_stack *s; + struct key *auth_tok_key = NULL; + int rc = 0; + + (*packet_size) = 0; + (*filename_size) = 0; + (*filename) = NULL; + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) { + printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc " + "[%zd] bytes of kernel memory\n", __func__, sizeof(*s)); + rc = -ENOMEM; + goto out; + } + s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { + printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " + "at least [%d]\n", __func__, max_packet_size, + ECRYPTFS_TAG_70_MIN_METADATA_SIZE); + rc = -EINVAL; + goto out; + } + /* Octet 0: Tag 70 identifier + * Octets 1-N1: Tag 70 packet size (includes cipher identifier + * and block-aligned encrypted filename size) + * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) + * Octet N2-N3: Cipher identifier (1 octet) + * Octets N3-N4: Block-aligned encrypted filename + * - Consists of a minimum number of random numbers, a \0 + * separator, and then the filename */ + if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { + printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " + "tag [0x%.2x]\n", __func__, + data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); + rc = -EINVAL; + goto out; + } + rc = ecryptfs_parse_packet_length(&data[(*packet_size)], + &s->parsed_tag_70_packet_size, + &s->packet_size_len); + if (rc) { + printk(KERN_WARNING "%s: Error parsing packet length; " + "rc = [%d]\n", __func__, rc); + goto out; + } + s->block_aligned_filename_size = (s->parsed_tag_70_packet_size + - ECRYPTFS_SIG_SIZE - 1); + if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) + > max_packet_size) { + printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " + "size is [%zd]\n", __func__, max_packet_size, + (1 + s->packet_size_len + 1 + + s->block_aligned_filename_size)); + rc = -EINVAL; + goto out; + } + (*packet_size) += s->packet_size_len; + ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], + ECRYPTFS_SIG_SIZE); + s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; + (*packet_size) += ECRYPTFS_SIG_SIZE; + s->cipher_code = data[(*packet_size)++]; + rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); + if (rc) { + printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", + __func__, s->cipher_code); + goto out; + } + rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, + &s->auth_tok, mount_crypt_stat, + s->fnek_sig_hex); + if (rc) { + printk(KERN_ERR "%s: Error attempting to find auth tok for " + "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, + rc); + goto out; + } + rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm, + &s->tfm_mutex, + s->cipher_string); + if (unlikely(rc)) { + printk(KERN_ERR "Internal error whilst attempting to get " + "tfm and mutex for cipher name [%s]; rc = [%d]\n", + s->cipher_string, rc); + goto out; + } + mutex_lock(s->tfm_mutex); + rc = virt_to_scatterlist(&data[(*packet_size)], + s->block_aligned_filename_size, s->src_sg, 2); + if (rc < 1) { + printk(KERN_ERR "%s: Internal error whilst attempting to " + "convert encrypted filename memory to scatterlist; " + "rc = [%d]. block_aligned_filename_size = [%zd]\n", + __func__, rc, s->block_aligned_filename_size); + goto out_unlock; + } + (*packet_size) += s->block_aligned_filename_size; + s->decrypted_filename = kmalloc(s->block_aligned_filename_size, + GFP_KERNEL); + if (!s->decrypted_filename) { + printk(KERN_ERR "%s: Out of memory whilst attempting to " + "kmalloc [%zd] bytes\n", __func__, + s->block_aligned_filename_size); + rc = -ENOMEM; + goto out_unlock; + } + rc = virt_to_scatterlist(s->decrypted_filename, + s->block_aligned_filename_size, s->dst_sg, 2); + if (rc < 1) { + printk(KERN_ERR "%s: Internal error whilst attempting to " + "convert decrypted filename memory to scatterlist; " + "rc = [%d]. block_aligned_filename_size = [%zd]\n", + __func__, rc, s->block_aligned_filename_size); + goto out_free_unlock; + } + /* The characters in the first block effectively do the job of + * the IV here, so we just use 0's for the IV. Note the + * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + * >= ECRYPTFS_MAX_IV_BYTES. */ + memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES); + s->desc.info = s->iv; + /* TODO: Support other key modules than passphrase for + * filename encryption */ + if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { + rc = -EOPNOTSUPP; + printk(KERN_INFO "%s: Filename encryption only supports " + "password tokens\n", __func__); + goto out_free_unlock; + } + rc = crypto_blkcipher_setkey( + s->desc.tfm, + s->auth_tok->token.password.session_key_encryption_key, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + if (rc < 0) { + printk(KERN_ERR "%s: Error setting key for crypto context; " + "rc = [%d]. s->auth_tok->token.password.session_key_" + "encryption_key = [0x%p]; mount_crypt_stat->" + "global_default_fn_cipher_key_bytes = [%zd]\n", __func__, + rc, + s->auth_tok->token.password.session_key_encryption_key, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + goto out_free_unlock; + } + rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg, + s->block_aligned_filename_size); + if (rc) { + printk(KERN_ERR "%s: Error attempting to decrypt filename; " + "rc = [%d]\n", __func__, rc); + goto out_free_unlock; + } + s->i = 0; + while (s->decrypted_filename[s->i] != '\0' + && s->i < s->block_aligned_filename_size) + s->i++; + if (s->i == s->block_aligned_filename_size) { + printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " + "find valid separator between random characters and " + "the filename\n", __func__); + rc = -EINVAL; + goto out_free_unlock; + } + s->i++; + (*filename_size) = (s->block_aligned_filename_size - s->i); + if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { + printk(KERN_WARNING "%s: Filename size is [%zd], which is " + "invalid\n", __func__, (*filename_size)); + rc = -EINVAL; + goto out_free_unlock; + } + (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); + if (!(*filename)) { + printk(KERN_ERR "%s: Out of memory whilst attempting to " + "kmalloc [%zd] bytes\n", __func__, + ((*filename_size) + 1)); + rc = -ENOMEM; + goto out_free_unlock; + } + memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); + (*filename)[(*filename_size)] = '\0'; +out_free_unlock: + kfree(s->decrypted_filename); +out_unlock: + mutex_unlock(s->tfm_mutex); +out: + if (rc) { + (*packet_size) = 0; + (*filename_size) = 0; + (*filename) = NULL; + } + if (auth_tok_key) { + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + } + kfree(s); + return rc; +} + +static int +ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) +{ + int rc = 0; + + (*sig) = NULL; + switch (auth_tok->token_type) { + case ECRYPTFS_PASSWORD: + (*sig) = auth_tok->token.password.signature; + break; + case ECRYPTFS_PRIVATE_KEY: + (*sig) = auth_tok->token.private_key.signature; + break; + default: + printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", + auth_tok->token_type); + rc = -EINVAL; + } + return rc; +} + +/** + * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. + * @auth_tok: The key authentication token used to decrypt the session key + * @crypt_stat: The cryptographic context + * + * Returns zero on success; non-zero error otherwise. + */ +static int +decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat) +{ + u8 cipher_code = 0; + struct ecryptfs_msg_ctx *msg_ctx; + struct ecryptfs_message *msg = NULL; + char *auth_tok_sig; + char *payload = NULL; + size_t payload_len = 0; + int rc; + + rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); + if (rc) { + printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", + auth_tok->token_type); + goto out; + } + rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), + &payload, &payload_len); + if (rc) { + ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); + goto out; + } + rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error sending message to " + "ecryptfsd: %d\n", rc); + goto out; + } + rc = ecryptfs_wait_for_response(msg_ctx, &msg); + if (rc) { + ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " + "from the user space daemon\n"); + rc = -EIO; + goto out; + } + rc = parse_tag_65_packet(&(auth_tok->session_key), + &cipher_code, msg); + if (rc) { + printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", + rc); + goto out; + } + auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; + memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, + auth_tok->session_key.decrypted_key_size); + crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; + rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); + if (rc) { + ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", + cipher_code) + goto out; + } + crypt_stat->flags |= ECRYPTFS_KEY_VALID; + if (ecryptfs_verbosity > 0) { + ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); + ecryptfs_dump_hex(crypt_stat->key, + crypt_stat->key_size); + } +out: + kfree(msg); + kfree(payload); + return rc; +} + +static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) +{ + struct ecryptfs_auth_tok_list_item *auth_tok_list_item; + struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; + + list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, + auth_tok_list_head, list) { + list_del(&auth_tok_list_item->list); + kmem_cache_free(ecryptfs_auth_tok_list_item_cache, + auth_tok_list_item); + } +} + +struct kmem_cache *ecryptfs_auth_tok_list_item_cache; + +/** + * parse_tag_1_packet + * @crypt_stat: The cryptographic context to modify based on packet contents + * @data: The raw bytes of the packet. + * @auth_tok_list: eCryptfs parses packets into authentication tokens; + * a new authentication token will be placed at the + * end of this list for this packet. + * @new_auth_tok: Pointer to a pointer to memory that this function + * allocates; sets the memory address of the pointer to + * NULL on error. This object is added to the + * auth_tok_list. + * @packet_size: This function writes the size of the parsed packet + * into this memory location; zero on error. + * @max_packet_size: The maximum allowable packet size + * + * Returns zero on success; non-zero on error. + */ +static int +parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, + unsigned char *data, struct list_head *auth_tok_list, + struct ecryptfs_auth_tok **new_auth_tok, + size_t *packet_size, size_t max_packet_size) +{ + size_t body_size; + struct ecryptfs_auth_tok_list_item *auth_tok_list_item; + size_t length_size; + int rc = 0; + + (*packet_size) = 0; + (*new_auth_tok) = NULL; + /** + * This format is inspired by OpenPGP; see RFC 2440 + * packet tag 1 + * + * Tag 1 identifier (1 byte) + * Max Tag 1 packet size (max 3 bytes) + * Version (1 byte) + * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) + * Cipher identifier (1 byte) + * Encrypted key size (arbitrary) + * + * 12 bytes minimum packet size + */ + if (unlikely(max_packet_size < 12)) { + printk(KERN_ERR "Invalid max packet size; must be >=12\n"); + rc = -EINVAL; + goto out; + } + if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { + printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", + ECRYPTFS_TAG_1_PACKET_TYPE); + rc = -EINVAL; + goto out; + } + /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or + * at end of function upon failure */ + auth_tok_list_item = + kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, + GFP_KERNEL); + if (!auth_tok_list_item) { + printk(KERN_ERR "Unable to allocate memory\n"); + rc = -ENOMEM; + goto out; + } + (*new_auth_tok) = &auth_tok_list_item->auth_tok; + rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, + &length_size); + if (rc) { + printk(KERN_WARNING "Error parsing packet length; " + "rc = [%d]\n", rc); + goto out_free; + } + if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { + printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); + rc = -EINVAL; + goto out_free; + } + (*packet_size) += length_size; + if (unlikely((*packet_size) + body_size > max_packet_size)) { + printk(KERN_WARNING "Packet size exceeds max\n"); + rc = -EINVAL; + goto out_free; + } + if (unlikely(data[(*packet_size)++] != 0x03)) { + printk(KERN_WARNING "Unknown version number [%d]\n", + data[(*packet_size) - 1]); + rc = -EINVAL; + goto out_free; + } + ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, + &data[(*packet_size)], ECRYPTFS_SIG_SIZE); + *packet_size += ECRYPTFS_SIG_SIZE; + /* This byte is skipped because the kernel does not need to + * know which public key encryption algorithm was used */ + (*packet_size)++; + (*new_auth_tok)->session_key.encrypted_key_size = + body_size - (ECRYPTFS_SIG_SIZE + 2); + if ((*new_auth_tok)->session_key.encrypted_key_size + > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { + printk(KERN_WARNING "Tag 1 packet contains key larger " + "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); + rc = -EINVAL; + goto out; + } + memcpy((*new_auth_tok)->session_key.encrypted_key, + &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); + (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; + (*new_auth_tok)->session_key.flags &= + ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; + (*new_auth_tok)->session_key.flags |= + ECRYPTFS_CONTAINS_ENCRYPTED_KEY; + (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; + (*new_auth_tok)->flags = 0; + (*new_auth_tok)->session_key.flags &= + ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); + (*new_auth_tok)->session_key.flags &= + ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); + list_add(&auth_tok_list_item->list, auth_tok_list); + goto out; +out_free: + (*new_auth_tok) = NULL; + memset(auth_tok_list_item, 0, + sizeof(struct ecryptfs_auth_tok_list_item)); + kmem_cache_free(ecryptfs_auth_tok_list_item_cache, + auth_tok_list_item); +out: + if (rc) + (*packet_size) = 0; + return rc; +} + +/** + * parse_tag_3_packet + * @crypt_stat: The cryptographic context to modify based on packet + * contents. + * @data: The raw bytes of the packet. + * @auth_tok_list: eCryptfs parses packets into authentication tokens; + * a new authentication token will be placed at the end + * of this list for this packet. + * @new_auth_tok: Pointer to a pointer to memory that this function + * allocates; sets the memory address of the pointer to + * NULL on error. This object is added to the + * auth_tok_list. + * @packet_size: This function writes the size of the parsed packet + * into this memory location; zero on error. + * @max_packet_size: maximum number of bytes to parse + * + * Returns zero on success; non-zero on error. + */ +static int +parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, + unsigned char *data, struct list_head *auth_tok_list, + struct ecryptfs_auth_tok **new_auth_tok, + size_t *packet_size, size_t max_packet_size) +{ + size_t body_size; + struct ecryptfs_auth_tok_list_item *auth_tok_list_item; + size_t length_size; + int rc = 0; + + (*packet_size) = 0; + (*new_auth_tok) = NULL; + /** + *This format is inspired by OpenPGP; see RFC 2440 + * packet tag 3 + * + * Tag 3 identifier (1 byte) + * Max Tag 3 packet size (max 3 bytes) + * Version (1 byte) + * Cipher code (1 byte) + * S2K specifier (1 byte) + * Hash identifier (1 byte) + * Salt (ECRYPTFS_SALT_SIZE) + * Hash iterations (1 byte) + * Encrypted key (arbitrary) + * + * (ECRYPTFS_SALT_SIZE + 7) minimum packet size + */ + if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { + printk(KERN_ERR "Max packet size too large\n"); + rc = -EINVAL; + goto out; + } + if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { + printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", + ECRYPTFS_TAG_3_PACKET_TYPE); + rc = -EINVAL; + goto out; + } + /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or + * at end of function upon failure */ + auth_tok_list_item = + kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); + if (!auth_tok_list_item) { + printk(KERN_ERR "Unable to allocate memory\n"); + rc = -ENOMEM; + goto out; + } + (*new_auth_tok) = &auth_tok_list_item->auth_tok; + rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, + &length_size); + if (rc) { + printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", + rc); + goto out_free; + } + if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { + printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); + rc = -EINVAL; + goto out_free; + } + (*packet_size) += length_size; + if (unlikely((*packet_size) + body_size > max_packet_size)) { + printk(KERN_ERR "Packet size exceeds max\n"); + rc = -EINVAL; + goto out_free; + } + (*new_auth_tok)->session_key.encrypted_key_size = + (body_size - (ECRYPTFS_SALT_SIZE + 5)); + if ((*new_auth_tok)->session_key.encrypted_key_size + > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { + printk(KERN_WARNING "Tag 3 packet contains key larger " + "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); + rc = -EINVAL; + goto out_free; + } + if (unlikely(data[(*packet_size)++] != 0x04)) { + printk(KERN_WARNING "Unknown version number [%d]\n", + data[(*packet_size) - 1]); + rc = -EINVAL; + goto out_free; + } + rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, + (u16)data[(*packet_size)]); + if (rc) + goto out_free; + /* A little extra work to differentiate among the AES key + * sizes; see RFC2440 */ + switch(data[(*packet_size)++]) { + case RFC2440_CIPHER_AES_192: + crypt_stat->key_size = 24; + break; + default: + crypt_stat->key_size = + (*new_auth_tok)->session_key.encrypted_key_size; + } + rc = ecryptfs_init_crypt_ctx(crypt_stat); + if (rc) + goto out_free; + if (unlikely(data[(*packet_size)++] != 0x03)) { + printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); + rc = -ENOSYS; + goto out_free; + } + /* TODO: finish the hash mapping */ + switch (data[(*packet_size)++]) { + case 0x01: /* See RFC2440 for these numbers and their mappings */ + /* Choose MD5 */ + memcpy((*new_auth_tok)->token.password.salt, + &data[(*packet_size)], ECRYPTFS_SALT_SIZE); + (*packet_size) += ECRYPTFS_SALT_SIZE; + /* This conversion was taken straight from RFC2440 */ + (*new_auth_tok)->token.password.hash_iterations = + ((u32) 16 + (data[(*packet_size)] & 15)) + << ((data[(*packet_size)] >> 4) + 6); + (*packet_size)++; + /* Friendly reminder: + * (*new_auth_tok)->session_key.encrypted_key_size = + * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ + memcpy((*new_auth_tok)->session_key.encrypted_key, + &data[(*packet_size)], + (*new_auth_tok)->session_key.encrypted_key_size); + (*packet_size) += + (*new_auth_tok)->session_key.encrypted_key_size; + (*new_auth_tok)->session_key.flags &= + ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; + (*new_auth_tok)->session_key.flags |= + ECRYPTFS_CONTAINS_ENCRYPTED_KEY; + (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ + break; + default: + ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " + "[%d]\n", data[(*packet_size) - 1]); + rc = -ENOSYS; + goto out_free; + } + (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; + /* TODO: Parametarize; we might actually want userspace to + * decrypt the session key. */ + (*new_auth_tok)->session_key.flags &= + ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); + (*new_auth_tok)->session_key.flags &= + ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); + list_add(&auth_tok_list_item->list, auth_tok_list); + goto out; +out_free: + (*new_auth_tok) = NULL; + memset(auth_tok_list_item, 0, + sizeof(struct ecryptfs_auth_tok_list_item)); + kmem_cache_free(ecryptfs_auth_tok_list_item_cache, + auth_tok_list_item); +out: + if (rc) + (*packet_size) = 0; + return rc; +} + +/** + * parse_tag_11_packet + * @data: The raw bytes of the packet + * @contents: This function writes the data contents of the literal + * packet into this memory location + * @max_contents_bytes: The maximum number of bytes that this function + * is allowed to write into contents + * @tag_11_contents_size: This function writes the size of the parsed + * contents into this memory location; zero on + * error + * @packet_size: This function writes the size of the parsed packet + * into this memory location; zero on error + * @max_packet_size: maximum number of bytes to parse + * + * Returns zero on success; non-zero on error. + */ +static int +parse_tag_11_packet(unsigned char *data, unsigned char *contents, + size_t max_contents_bytes, size_t *tag_11_contents_size, + size_t *packet_size, size_t max_packet_size) +{ + size_t body_size; + size_t length_size; + int rc = 0; + + (*packet_size) = 0; + (*tag_11_contents_size) = 0; + /* This format is inspired by OpenPGP; see RFC 2440 + * packet tag 11 + * + * Tag 11 identifier (1 byte) + * Max Tag 11 packet size (max 3 bytes) + * Binary format specifier (1 byte) + * Filename length (1 byte) + * Filename ("_CONSOLE") (8 bytes) + * Modification date (4 bytes) + * Literal data (arbitrary) + * + * We need at least 16 bytes of data for the packet to even be + * valid. + */ + if (max_packet_size < 16) { + printk(KERN_ERR "Maximum packet size too small\n"); + rc = -EINVAL; + goto out; + } + if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { + printk(KERN_WARNING "Invalid tag 11 packet format\n"); + rc = -EINVAL; + goto out; + } + rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, + &length_size); + if (rc) { + printk(KERN_WARNING "Invalid tag 11 packet format\n"); + goto out; + } + if (body_size < 14) { + printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); + rc = -EINVAL; + goto out; + } + (*packet_size) += length_size; + (*tag_11_contents_size) = (body_size - 14); + if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { + printk(KERN_ERR "Packet size exceeds max\n"); + rc = -EINVAL; + goto out; + } + if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { + printk(KERN_ERR "Literal data section in tag 11 packet exceeds " + "expected size\n"); + rc = -EINVAL; + goto out; + } + if (data[(*packet_size)++] != 0x62) { + printk(KERN_WARNING "Unrecognizable packet\n"); + rc = -EINVAL; + goto out; + } + if (data[(*packet_size)++] != 0x08) { + printk(KERN_WARNING "Unrecognizable packet\n"); + rc = -EINVAL; + goto out; + } + (*packet_size) += 12; /* Ignore filename and modification date */ + memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); + (*packet_size) += (*tag_11_contents_size); +out: + if (rc) { + (*packet_size) = 0; + (*tag_11_contents_size) = 0; + } + return rc; +} + +int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, + struct ecryptfs_auth_tok **auth_tok, + char *sig) +{ + int rc = 0; + + (*auth_tok_key) = request_key(&key_type_user, sig, NULL); + if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { + (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); + if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) { + printk(KERN_ERR "Could not find key with description: [%s]\n", + sig); + rc = process_request_key_err(PTR_ERR(*auth_tok_key)); + (*auth_tok_key) = NULL; + goto out; + } + } + down_write(&(*auth_tok_key)->sem); + rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); + if (rc) { + up_write(&(*auth_tok_key)->sem); + key_put(*auth_tok_key); + (*auth_tok_key) = NULL; + goto out; + } +out: + return rc; +} + +/** + * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. + * @auth_tok: The passphrase authentication token to use to encrypt the FEK + * @crypt_stat: The cryptographic context + * + * Returns zero on success; non-zero error otherwise + */ +static int +decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat) +{ + struct scatterlist dst_sg[2]; + struct scatterlist src_sg[2]; + struct mutex *tfm_mutex; + struct blkcipher_desc desc = { + .flags = CRYPTO_TFM_REQ_MAY_SLEEP + }; + int rc = 0; + + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk( + KERN_DEBUG, "Session key encryption key (size [%d]):\n", + auth_tok->token.password.session_key_encryption_key_bytes); + ecryptfs_dump_hex( + auth_tok->token.password.session_key_encryption_key, + auth_tok->token.password.session_key_encryption_key_bytes); + } + rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, + crypt_stat->cipher); + if (unlikely(rc)) { + printk(KERN_ERR "Internal error whilst attempting to get " + "tfm and mutex for cipher name [%s]; rc = [%d]\n", + crypt_stat->cipher, rc); + goto out; + } + rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, + auth_tok->session_key.encrypted_key_size, + src_sg, 2); + if (rc < 1 || rc > 2) { + printk(KERN_ERR "Internal error whilst attempting to convert " + "auth_tok->session_key.encrypted_key to scatterlist; " + "expected rc = 1; got rc = [%d]. " + "auth_tok->session_key.encrypted_key_size = [%d]\n", rc, + auth_tok->session_key.encrypted_key_size); + goto out; + } + auth_tok->session_key.decrypted_key_size = + auth_tok->session_key.encrypted_key_size; + rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, + auth_tok->session_key.decrypted_key_size, + dst_sg, 2); + if (rc < 1 || rc > 2) { + printk(KERN_ERR "Internal error whilst attempting to convert " + "auth_tok->session_key.decrypted_key to scatterlist; " + "expected rc = 1; got rc = [%d]\n", rc); + goto out; + } + mutex_lock(tfm_mutex); + rc = crypto_blkcipher_setkey( + desc.tfm, auth_tok->token.password.session_key_encryption_key, + crypt_stat->key_size); + if (unlikely(rc < 0)) { + mutex_unlock(tfm_mutex); + printk(KERN_ERR "Error setting key for crypto context\n"); + rc = -EINVAL; + goto out; + } + rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, + auth_tok->session_key.encrypted_key_size); + mutex_unlock(tfm_mutex); + if (unlikely(rc)) { + printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); + goto out; + } + auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; + memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, + auth_tok->session_key.decrypted_key_size); + crypt_stat->flags |= ECRYPTFS_KEY_VALID; + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", + crypt_stat->key_size); + ecryptfs_dump_hex(crypt_stat->key, + crypt_stat->key_size); + } +out: + return rc; +} + +/** + * ecryptfs_parse_packet_set + * @crypt_stat: The cryptographic context + * @src: Virtual address of region of memory containing the packets + * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set + * + * Get crypt_stat to have the file's session key if the requisite key + * is available to decrypt the session key. + * + * Returns Zero if a valid authentication token was retrieved and + * processed; negative value for file not encrypted or for error + * conditions. + */ +int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, + unsigned char *src, + struct dentry *ecryptfs_dentry) +{ + size_t i = 0; + size_t found_auth_tok; + size_t next_packet_is_auth_tok_packet; + struct list_head auth_tok_list; + struct ecryptfs_auth_tok *matching_auth_tok; + struct ecryptfs_auth_tok *candidate_auth_tok; + char *candidate_auth_tok_sig; + size_t packet_size; + struct ecryptfs_auth_tok *new_auth_tok; + unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; + struct ecryptfs_auth_tok_list_item *auth_tok_list_item; + size_t tag_11_contents_size; + size_t tag_11_packet_size; + struct key *auth_tok_key = NULL; + int rc = 0; + + INIT_LIST_HEAD(&auth_tok_list); + /* Parse the header to find as many packets as we can; these will be + * added the our &auth_tok_list */ + next_packet_is_auth_tok_packet = 1; + while (next_packet_is_auth_tok_packet) { + size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i); + + switch (src[i]) { + case ECRYPTFS_TAG_3_PACKET_TYPE: + rc = parse_tag_3_packet(crypt_stat, + (unsigned char *)&src[i], + &auth_tok_list, &new_auth_tok, + &packet_size, max_packet_size); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error parsing " + "tag 3 packet\n"); + rc = -EIO; + goto out_wipe_list; + } + i += packet_size; + rc = parse_tag_11_packet((unsigned char *)&src[i], + sig_tmp_space, + ECRYPTFS_SIG_SIZE, + &tag_11_contents_size, + &tag_11_packet_size, + max_packet_size); + if (rc) { + ecryptfs_printk(KERN_ERR, "No valid " + "(ecryptfs-specific) literal " + "packet containing " + "authentication token " + "signature found after " + "tag 3 packet\n"); + rc = -EIO; + goto out_wipe_list; + } + i += tag_11_packet_size; + if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { + ecryptfs_printk(KERN_ERR, "Expected " + "signature of size [%d]; " + "read size [%zd]\n", + ECRYPTFS_SIG_SIZE, + tag_11_contents_size); + rc = -EIO; + goto out_wipe_list; + } + ecryptfs_to_hex(new_auth_tok->token.password.signature, + sig_tmp_space, tag_11_contents_size); + new_auth_tok->token.password.signature[ + ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; + crypt_stat->flags |= ECRYPTFS_ENCRYPTED; + break; + case ECRYPTFS_TAG_1_PACKET_TYPE: + rc = parse_tag_1_packet(crypt_stat, + (unsigned char *)&src[i], + &auth_tok_list, &new_auth_tok, + &packet_size, max_packet_size); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error parsing " + "tag 1 packet\n"); + rc = -EIO; + goto out_wipe_list; + } + i += packet_size; + crypt_stat->flags |= ECRYPTFS_ENCRYPTED; + break; + case ECRYPTFS_TAG_11_PACKET_TYPE: + ecryptfs_printk(KERN_WARNING, "Invalid packet set " + "(Tag 11 not allowed by itself)\n"); + rc = -EIO; + goto out_wipe_list; + default: + ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " + "of the file header; hex value of " + "character is [0x%.2x]\n", i, src[i]); + next_packet_is_auth_tok_packet = 0; + } + } + if (list_empty(&auth_tok_list)) { + printk(KERN_ERR "The lower file appears to be a non-encrypted " + "eCryptfs file; this is not supported in this version " + "of the eCryptfs kernel module\n"); + rc = -EINVAL; + goto out; + } + /* auth_tok_list contains the set of authentication tokens + * parsed from the metadata. We need to find a matching + * authentication token that has the secret component(s) + * necessary to decrypt the EFEK in the auth_tok parsed from + * the metadata. There may be several potential matches, but + * just one will be sufficient to decrypt to get the FEK. */ +find_next_matching_auth_tok: + found_auth_tok = 0; + list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { + candidate_auth_tok = &auth_tok_list_item->auth_tok; + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, + "Considering cadidate auth tok:\n"); + ecryptfs_dump_auth_tok(candidate_auth_tok); + } + rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, + candidate_auth_tok); + if (rc) { + printk(KERN_ERR + "Unrecognized candidate auth tok type: [%d]\n", + candidate_auth_tok->token_type); + rc = -EINVAL; + goto out_wipe_list; + } + rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, + &matching_auth_tok, + crypt_stat->mount_crypt_stat, + candidate_auth_tok_sig); + if (!rc) { + found_auth_tok = 1; + goto found_matching_auth_tok; + } + } + if (!found_auth_tok) { + ecryptfs_printk(KERN_ERR, "Could not find a usable " + "authentication token\n"); + rc = -EIO; + goto out_wipe_list; + } +found_matching_auth_tok: + if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { + memcpy(&(candidate_auth_tok->token.private_key), + &(matching_auth_tok->token.private_key), + sizeof(struct ecryptfs_private_key)); + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, + crypt_stat); + } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { + memcpy(&(candidate_auth_tok->token.password), + &(matching_auth_tok->token.password), + sizeof(struct ecryptfs_password)); + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + rc = decrypt_passphrase_encrypted_session_key( + candidate_auth_tok, crypt_stat); + } else { + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + rc = -EINVAL; + } + if (rc) { + struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; + + ecryptfs_printk(KERN_WARNING, "Error decrypting the " + "session key for authentication token with sig " + "[%.*s]; rc = [%d]. Removing auth tok " + "candidate from the list and searching for " + "the next match.\n", ECRYPTFS_SIG_SIZE_HEX, + candidate_auth_tok_sig, rc); + list_for_each_entry_safe(auth_tok_list_item, + auth_tok_list_item_tmp, + &auth_tok_list, list) { + if (candidate_auth_tok + == &auth_tok_list_item->auth_tok) { + list_del(&auth_tok_list_item->list); + kmem_cache_free( + ecryptfs_auth_tok_list_item_cache, + auth_tok_list_item); + goto find_next_matching_auth_tok; + } + } + BUG(); + } + rc = ecryptfs_compute_root_iv(crypt_stat); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error computing " + "the root IV\n"); + goto out_wipe_list; + } + rc = ecryptfs_init_crypt_ctx(crypt_stat); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error initializing crypto " + "context for cipher [%s]; rc = [%d]\n", + crypt_stat->cipher, rc); + } +out_wipe_list: + wipe_auth_tok_list(&auth_tok_list); +out: + return rc; +} + +static int +pki_encrypt_session_key(struct key *auth_tok_key, + struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat, + struct ecryptfs_key_record *key_rec) +{ + struct ecryptfs_msg_ctx *msg_ctx = NULL; + char *payload = NULL; + size_t payload_len = 0; + struct ecryptfs_message *msg; + int rc; + + rc = write_tag_66_packet(auth_tok->token.private_key.signature, + ecryptfs_code_for_cipher_string( + crypt_stat->cipher, + crypt_stat->key_size), + crypt_stat, &payload, &payload_len); + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); + goto out; + } + rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error sending message to " + "ecryptfsd: %d\n", rc); + goto out; + } + rc = ecryptfs_wait_for_response(msg_ctx, &msg); + if (rc) { + ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " + "from the user space daemon\n"); + rc = -EIO; + goto out; + } + rc = parse_tag_67_packet(key_rec, msg); + if (rc) + ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); + kfree(msg); +out: + kfree(payload); + return rc; +} +/** + * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet + * @dest: Buffer into which to write the packet + * @remaining_bytes: Maximum number of bytes that can be writtn + * @auth_tok_key: The authentication token key to unlock and put when done with + * @auth_tok + * @auth_tok: The authentication token used for generating the tag 1 packet + * @crypt_stat: The cryptographic context + * @key_rec: The key record struct for the tag 1 packet + * @packet_size: This function will write the number of bytes that end + * up constituting the packet; set to zero on error + * + * Returns zero on success; non-zero on error. + */ +static int +write_tag_1_packet(char *dest, size_t *remaining_bytes, + struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat, + struct ecryptfs_key_record *key_rec, size_t *packet_size) +{ + size_t i; + size_t encrypted_session_key_valid = 0; + size_t packet_size_length; + size_t max_packet_size; + int rc = 0; + + (*packet_size) = 0; + ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, + ECRYPTFS_SIG_SIZE); + encrypted_session_key_valid = 0; + for (i = 0; i < crypt_stat->key_size; i++) + encrypted_session_key_valid |= + auth_tok->session_key.encrypted_key[i]; + if (encrypted_session_key_valid) { + memcpy(key_rec->enc_key, + auth_tok->session_key.encrypted_key, + auth_tok->session_key.encrypted_key_size); + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + goto encrypted_session_key_set; + } + if (auth_tok->session_key.encrypted_key_size == 0) + auth_tok->session_key.encrypted_key_size = + auth_tok->token.private_key.key_size; + rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, + key_rec); + if (rc) { + printk(KERN_ERR "Failed to encrypt session key via a key " + "module; rc = [%d]\n", rc); + goto out; + } + if (ecryptfs_verbosity > 0) { + ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); + ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); + } +encrypted_session_key_set: + /* This format is inspired by OpenPGP; see RFC 2440 + * packet tag 1 */ + max_packet_size = (1 /* Tag 1 identifier */ + + 3 /* Max Tag 1 packet size */ + + 1 /* Version */ + + ECRYPTFS_SIG_SIZE /* Key identifier */ + + 1 /* Cipher identifier */ + + key_rec->enc_key_size); /* Encrypted key size */ + if (max_packet_size > (*remaining_bytes)) { + printk(KERN_ERR "Packet length larger than maximum allowable; " + "need up to [%td] bytes, but there are only [%td] " + "available\n", max_packet_size, (*remaining_bytes)); + rc = -EINVAL; + goto out; + } + dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; + rc = ecryptfs_write_packet_length(&dest[(*packet_size)], + (max_packet_size - 4), + &packet_size_length); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " + "header; cannot generate packet length\n"); + goto out; + } + (*packet_size) += packet_size_length; + dest[(*packet_size)++] = 0x03; /* version 3 */ + memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); + (*packet_size) += ECRYPTFS_SIG_SIZE; + dest[(*packet_size)++] = RFC2440_CIPHER_RSA; + memcpy(&dest[(*packet_size)], key_rec->enc_key, + key_rec->enc_key_size); + (*packet_size) += key_rec->enc_key_size; +out: + if (rc) + (*packet_size) = 0; + else + (*remaining_bytes) -= (*packet_size); + return rc; +} + +/** + * write_tag_11_packet + * @dest: Target into which Tag 11 packet is to be written + * @remaining_bytes: Maximum packet length + * @contents: Byte array of contents to copy in + * @contents_length: Number of bytes in contents + * @packet_length: Length of the Tag 11 packet written; zero on error + * + * Returns zero on success; non-zero on error. + */ +static int +write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, + size_t contents_length, size_t *packet_length) +{ + size_t packet_size_length; + size_t max_packet_size; + int rc = 0; + + (*packet_length) = 0; + /* This format is inspired by OpenPGP; see RFC 2440 + * packet tag 11 */ + max_packet_size = (1 /* Tag 11 identifier */ + + 3 /* Max Tag 11 packet size */ + + 1 /* Binary format specifier */ + + 1 /* Filename length */ + + 8 /* Filename ("_CONSOLE") */ + + 4 /* Modification date */ + + contents_length); /* Literal data */ + if (max_packet_size > (*remaining_bytes)) { + printk(KERN_ERR "Packet length larger than maximum allowable; " + "need up to [%td] bytes, but there are only [%td] " + "available\n", max_packet_size, (*remaining_bytes)); + rc = -EINVAL; + goto out; + } + dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; + rc = ecryptfs_write_packet_length(&dest[(*packet_length)], + (max_packet_size - 4), + &packet_size_length); + if (rc) { + printk(KERN_ERR "Error generating tag 11 packet header; cannot " + "generate packet length. rc = [%d]\n", rc); + goto out; + } + (*packet_length) += packet_size_length; + dest[(*packet_length)++] = 0x62; /* binary data format specifier */ + dest[(*packet_length)++] = 8; + memcpy(&dest[(*packet_length)], "_CONSOLE", 8); + (*packet_length) += 8; + memset(&dest[(*packet_length)], 0x00, 4); + (*packet_length) += 4; + memcpy(&dest[(*packet_length)], contents, contents_length); + (*packet_length) += contents_length; + out: + if (rc) + (*packet_length) = 0; + else + (*remaining_bytes) -= (*packet_length); + return rc; +} + +/** + * write_tag_3_packet + * @dest: Buffer into which to write the packet + * @remaining_bytes: Maximum number of bytes that can be written + * @auth_tok: Authentication token + * @crypt_stat: The cryptographic context + * @key_rec: encrypted key + * @packet_size: This function will write the number of bytes that end + * up constituting the packet; set to zero on error + * + * Returns zero on success; non-zero on error. + */ +static int +write_tag_3_packet(char *dest, size_t *remaining_bytes, + struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat, + struct ecryptfs_key_record *key_rec, size_t *packet_size) +{ + size_t i; + size_t encrypted_session_key_valid = 0; + char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; + struct scatterlist dst_sg[2]; + struct scatterlist src_sg[2]; + struct mutex *tfm_mutex = NULL; + u8 cipher_code; + size_t packet_size_length; + size_t max_packet_size; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat = + crypt_stat->mount_crypt_stat; + struct blkcipher_desc desc = { + .tfm = NULL, + .flags = CRYPTO_TFM_REQ_MAY_SLEEP + }; + int rc = 0; + + (*packet_size) = 0; + ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, + ECRYPTFS_SIG_SIZE); + rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, + crypt_stat->cipher); + if (unlikely(rc)) { + printk(KERN_ERR "Internal error whilst attempting to get " + "tfm and mutex for cipher name [%s]; rc = [%d]\n", + crypt_stat->cipher, rc); + goto out; + } + if (mount_crypt_stat->global_default_cipher_key_size == 0) { + struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm); + + printk(KERN_WARNING "No key size specified at mount; " + "defaulting to [%d]\n", alg->max_keysize); + mount_crypt_stat->global_default_cipher_key_size = + alg->max_keysize; + } + if (crypt_stat->key_size == 0) + crypt_stat->key_size = + mount_crypt_stat->global_default_cipher_key_size; + if (auth_tok->session_key.encrypted_key_size == 0) + auth_tok->session_key.encrypted_key_size = + crypt_stat->key_size; + if (crypt_stat->key_size == 24 + && strcmp("aes", crypt_stat->cipher) == 0) { + memset((crypt_stat->key + 24), 0, 8); + auth_tok->session_key.encrypted_key_size = 32; + } else + auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; + key_rec->enc_key_size = + auth_tok->session_key.encrypted_key_size; + encrypted_session_key_valid = 0; + for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) + encrypted_session_key_valid |= + auth_tok->session_key.encrypted_key[i]; + if (encrypted_session_key_valid) { + ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " + "using auth_tok->session_key.encrypted_key, " + "where key_rec->enc_key_size = [%zd]\n", + key_rec->enc_key_size); + memcpy(key_rec->enc_key, + auth_tok->session_key.encrypted_key, + key_rec->enc_key_size); + goto encrypted_session_key_set; + } + if (auth_tok->token.password.flags & + ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { + ecryptfs_printk(KERN_DEBUG, "Using previously generated " + "session key encryption key of size [%d]\n", + auth_tok->token.password. + session_key_encryption_key_bytes); + memcpy(session_key_encryption_key, + auth_tok->token.password.session_key_encryption_key, + crypt_stat->key_size); + ecryptfs_printk(KERN_DEBUG, + "Cached session key encryption key:\n"); + if (ecryptfs_verbosity > 0) + ecryptfs_dump_hex(session_key_encryption_key, 16); + } + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); + ecryptfs_dump_hex(session_key_encryption_key, 16); + } + rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, + src_sg, 2); + if (rc < 1 || rc > 2) { + ecryptfs_printk(KERN_ERR, "Error generating scatterlist " + "for crypt_stat session key; expected rc = 1; " + "got rc = [%d]. key_rec->enc_key_size = [%zd]\n", + rc, key_rec->enc_key_size); + rc = -ENOMEM; + goto out; + } + rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, + dst_sg, 2); + if (rc < 1 || rc > 2) { + ecryptfs_printk(KERN_ERR, "Error generating scatterlist " + "for crypt_stat encrypted session key; " + "expected rc = 1; got rc = [%d]. " + "key_rec->enc_key_size = [%zd]\n", rc, + key_rec->enc_key_size); + rc = -ENOMEM; + goto out; + } + mutex_lock(tfm_mutex); + rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, + crypt_stat->key_size); + if (rc < 0) { + mutex_unlock(tfm_mutex); + ecryptfs_printk(KERN_ERR, "Error setting key for crypto " + "context; rc = [%d]\n", rc); + goto out; + } + rc = 0; + ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", + crypt_stat->key_size); + rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, + (*key_rec).enc_key_size); + mutex_unlock(tfm_mutex); + if (rc) { + printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); + goto out; + } + ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); + if (ecryptfs_verbosity > 0) { + ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", + key_rec->enc_key_size); + ecryptfs_dump_hex(key_rec->enc_key, + key_rec->enc_key_size); + } +encrypted_session_key_set: + /* This format is inspired by OpenPGP; see RFC 2440 + * packet tag 3 */ + max_packet_size = (1 /* Tag 3 identifier */ + + 3 /* Max Tag 3 packet size */ + + 1 /* Version */ + + 1 /* Cipher code */ + + 1 /* S2K specifier */ + + 1 /* Hash identifier */ + + ECRYPTFS_SALT_SIZE /* Salt */ + + 1 /* Hash iterations */ + + key_rec->enc_key_size); /* Encrypted key size */ + if (max_packet_size > (*remaining_bytes)) { + printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " + "there are only [%td] available\n", max_packet_size, + (*remaining_bytes)); + rc = -EINVAL; + goto out; + } + dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; + /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) + * to get the number of octets in the actual Tag 3 packet */ + rc = ecryptfs_write_packet_length(&dest[(*packet_size)], + (max_packet_size - 4), + &packet_size_length); + if (rc) { + printk(KERN_ERR "Error generating tag 3 packet header; cannot " + "generate packet length. rc = [%d]\n", rc); + goto out; + } + (*packet_size) += packet_size_length; + dest[(*packet_size)++] = 0x04; /* version 4 */ + /* TODO: Break from RFC2440 so that arbitrary ciphers can be + * specified with strings */ + cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, + crypt_stat->key_size); + if (cipher_code == 0) { + ecryptfs_printk(KERN_WARNING, "Unable to generate code for " + "cipher [%s]\n", crypt_stat->cipher); + rc = -EINVAL; + goto out; + } + dest[(*packet_size)++] = cipher_code; + dest[(*packet_size)++] = 0x03; /* S2K */ + dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ + memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, + ECRYPTFS_SALT_SIZE); + (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ + dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ + memcpy(&dest[(*packet_size)], key_rec->enc_key, + key_rec->enc_key_size); + (*packet_size) += key_rec->enc_key_size; +out: + if (rc) + (*packet_size) = 0; + else + (*remaining_bytes) -= (*packet_size); + return rc; +} + +struct kmem_cache *ecryptfs_key_record_cache; + +/** + * ecryptfs_generate_key_packet_set + * @dest_base: Virtual address from which to write the key record set + * @crypt_stat: The cryptographic context from which the + * authentication tokens will be retrieved + * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat + * for the global parameters + * @len: The amount written + * @max: The maximum amount of data allowed to be written + * + * Generates a key packet set and writes it to the virtual address + * passed in. + * + * Returns zero on success; non-zero on error. + */ +int +ecryptfs_generate_key_packet_set(char *dest_base, + struct ecryptfs_crypt_stat *crypt_stat, + struct dentry *ecryptfs_dentry, size_t *len, + size_t max) +{ + struct ecryptfs_auth_tok *auth_tok; + struct key *auth_tok_key = NULL; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat = + &ecryptfs_superblock_to_private( + ecryptfs_dentry->d_sb)->mount_crypt_stat; + size_t written; + struct ecryptfs_key_record *key_rec; + struct ecryptfs_key_sig *key_sig; + int rc = 0; + + (*len) = 0; + mutex_lock(&crypt_stat->keysig_list_mutex); + key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); + if (!key_rec) { + rc = -ENOMEM; + goto out; + } + list_for_each_entry(key_sig, &crypt_stat->keysig_list, + crypt_stat_list) { + memset(key_rec, 0, sizeof(*key_rec)); + rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, + &auth_tok, + mount_crypt_stat, + key_sig->keysig); + if (rc) { + printk(KERN_WARNING "Unable to retrieve auth tok with " + "sig = [%s]\n", key_sig->keysig); + rc = process_find_global_auth_tok_for_sig_err(rc); + goto out_free; + } + if (auth_tok->token_type == ECRYPTFS_PASSWORD) { + rc = write_tag_3_packet((dest_base + (*len)), + &max, auth_tok, + crypt_stat, key_rec, + &written); + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + if (rc) { + ecryptfs_printk(KERN_WARNING, "Error " + "writing tag 3 packet\n"); + goto out_free; + } + (*len) += written; + /* Write auth tok signature packet */ + rc = write_tag_11_packet((dest_base + (*len)), &max, + key_rec->sig, + ECRYPTFS_SIG_SIZE, &written); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error writing " + "auth tok signature packet\n"); + goto out_free; + } + (*len) += written; + } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { + rc = write_tag_1_packet(dest_base + (*len), &max, + auth_tok_key, auth_tok, + crypt_stat, key_rec, &written); + if (rc) { + ecryptfs_printk(KERN_WARNING, "Error " + "writing tag 1 packet\n"); + goto out_free; + } + (*len) += written; + } else { + up_write(&(auth_tok_key->sem)); + key_put(auth_tok_key); + ecryptfs_printk(KERN_WARNING, "Unsupported " + "authentication token type\n"); + rc = -EINVAL; + goto out_free; + } + } + if (likely(max > 0)) { + dest_base[(*len)] = 0x00; + } else { + ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); + rc = -EIO; + } +out_free: + kmem_cache_free(ecryptfs_key_record_cache, key_rec); +out: + if (rc) + (*len) = 0; + mutex_unlock(&crypt_stat->keysig_list_mutex); + return rc; +} + +struct kmem_cache *ecryptfs_key_sig_cache; + +int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) +{ + struct ecryptfs_key_sig *new_key_sig; + + new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); + if (!new_key_sig) { + printk(KERN_ERR + "Error allocating from ecryptfs_key_sig_cache\n"); + return -ENOMEM; + } + memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); + new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; + /* Caller must hold keysig_list_mutex */ + list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); + + return 0; +} + +struct kmem_cache *ecryptfs_global_auth_tok_cache; + +int +ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, + char *sig, u32 global_auth_tok_flags) +{ + struct ecryptfs_global_auth_tok *new_auth_tok; + int rc = 0; + + new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, + GFP_KERNEL); + if (!new_auth_tok) { + rc = -ENOMEM; + printk(KERN_ERR "Error allocating from " + "ecryptfs_global_auth_tok_cache\n"); + goto out; + } + memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); + new_auth_tok->flags = global_auth_tok_flags; + new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; + mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); + list_add(&new_auth_tok->mount_crypt_stat_list, + &mount_crypt_stat->global_auth_tok_list); + mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); +out: + return rc; +} + |