| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Michael Halcrow | 9679 | 87.55% | 25 | 30.86% |
| Roberto Sassu | 671 | 6.07% | 9 | 11.11% |
| Herbert Xu | 370 | 3.35% | 2 | 2.47% |
| Tyler Hicks | 199 | 1.80% | 12 | 14.81% |
| Eric Biggers | 29 | 0.26% | 2 | 2.47% |
| Ramon de Carvalho Valle | 19 | 0.17% | 1 | 1.23% |
| Andrew Morton | 8 | 0.07% | 1 | 1.23% |
| Eric Sandeen | 7 | 0.06% | 2 | 2.47% |
| Geyslan G. Bem | 7 | 0.06% | 1 | 1.23% |
| Lee Jones | 6 | 0.05% | 1 | 1.23% |
| Roland Dreier | 6 | 0.05% | 1 | 1.23% |
| Kees Cook | 6 | 0.05% | 1 | 1.23% |
| Greg Kroah-Hartman | 5 | 0.05% | 1 | 1.23% |
| Trevor Highland | 4 | 0.04% | 1 | 1.23% |
| Colin Ian King | 4 | 0.04% | 3 | 3.70% |
| Harvey Harrison | 4 | 0.04% | 1 | 1.23% |
| Julia Lawall | 4 | 0.04% | 1 | 1.23% |
| SF Markus Elfring | 4 | 0.04% | 2 | 2.47% |
| Dan Carpenter | 3 | 0.03% | 1 | 1.23% |
| Tom Rix | 3 | 0.03% | 1 | 1.23% |
| Joe Perches | 3 | 0.03% | 1 | 1.23% |
| Cyrill V. Gorcunov | 2 | 0.02% | 1 | 1.23% |
| Waiman Long | 2 | 0.02% | 1 | 1.23% |
| Linus Torvalds (pre-git) | 2 | 0.02% | 1 | 1.23% |
| Simon Que | 2 | 0.02% | 1 | 1.23% |
| Thomas Gleixner | 1 | 0.01% | 1 | 1.23% |
| Linus Torvalds | 1 | 0.01% | 1 | 1.23% |
| Christoph Lameter | 1 | 0.01% | 1 | 1.23% |
| Kirill A. Shutemov | 1 | 0.01% | 1 | 1.23% |
| Wenwen Wang | 1 | 0.01% | 1 | 1.23% |
| Jean Delvare | 1 | 0.01% | 1 | 1.23% |
| Robert P. J. Day | 1 | 0.01% | 1 | 1.23% |
| Total | 11056 | 81 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * 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> */ #include <crypto/hash.h> #include <crypto/skcipher.h> #include <linux/string.h> #include <linux/pagemap.h> #include <linux/key.h> #include <linux/random.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 if the payload is invalid; or * -EKEYREVOKED if the key was revoked before we acquired its semaphore. */ 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 (IS_ERR(*auth_tok)) { rc = PTR_ERR(*auth_tok); *auth_tok = NULL; goto out; } 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_key: key containing the authentication token * @auth_tok: Set to the matching auth_tok; NULL if not found * @mount_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 crypto_skcipher *skcipher_tfm; struct skcipher_request *skcipher_req; char iv[ECRYPTFS_MAX_IV_BYTES]; char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; struct crypto_shash *hash_tfm; struct shash_desc *hash_desc; }; /* * 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 = kzalloc(sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; (*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->skcipher_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_skcipher_blocksize(s->skcipher_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) { (*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->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); if (!s->skcipher_req) { printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " "skcipher_request_alloc for %s\n", __func__, crypto_skcipher_driver_name(s->skcipher_tfm)); rc = -ENOMEM; goto out_unlock; } skcipher_request_set_callback(s->skcipher_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, GFP_KERNEL); if (!s->block_aligned_filename) { rc = -ENOMEM; goto out_unlock; } 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; } s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); if (IS_ERR(s->hash_tfm)) { rc = PTR_ERR(s->hash_tfm); printk(KERN_ERR "%s: Error attempting to " "allocate hash crypto context; rc = [%d]\n", __func__, rc); goto out_free_unlock; } s->hash_desc = kmalloc(sizeof(*s->hash_desc) + crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); if (!s->hash_desc) { rc = -ENOMEM; goto out_release_free_unlock; } s->hash_desc->tfm = s->hash_tfm; rc = crypto_shash_digest(s->hash_desc, (u8 *)s->auth_tok->token.password.session_key_encryption_key, s->auth_tok->token.password.session_key_encryption_key_bytes, s->hash); if (rc) { printk(KERN_ERR "%s: Error computing 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)) { rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, ECRYPTFS_TAG_70_DIGEST_SIZE, s->tmp_hash); if (rc) { printk(KERN_ERR "%s: Error computing 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. */ rc = crypto_skcipher_setkey( s->skcipher_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; } skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, s->block_aligned_filename_size, s->iv); rc = crypto_skcipher_encrypt(s->skcipher_req); 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_shash(s->hash_tfm); out_free_unlock: kfree_sensitive(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); } skcipher_request_free(s->skcipher_req); kfree_sensitive(s->hash_desc); 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 crypto_skcipher *skcipher_tfm; struct skcipher_request *skcipher_req; char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; char iv[ECRYPTFS_MAX_IV_BYTES]; char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; }; /** * ecryptfs_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 = kzalloc(sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; 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->skcipher_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) { 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; } s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); if (!s->skcipher_req) { printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " "skcipher_request_alloc for %s\n", __func__, crypto_skcipher_driver_name(s->skcipher_tfm)); rc = -ENOMEM; goto out_free_unlock; } skcipher_request_set_callback(s->skcipher_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); /* 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. */ /* 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_skcipher_setkey( s->skcipher_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; } skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, s->block_aligned_filename_size, s->iv); rc = crypto_skcipher_decrypt(s->skcipher_req); if (rc) { printk(KERN_ERR "%s: Error attempting to decrypt filename; " "rc = [%d]\n", __func__, rc); goto out_free_unlock; } while (s->i < s->block_aligned_filename_size && s->decrypted_filename[s->i] != '\0') 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)) { 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); } skcipher_request_free(s->skcipher_req); 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\n"); rc = -EINVAL; goto out_free; } 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 (IS_ERR(*auth_tok_key)) { (*auth_tok_key) = ecryptfs_get_encrypted_key(sig); if (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 crypto_skcipher *tfm; struct skcipher_request *req = NULL; 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(&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); req = skcipher_request_alloc(tfm, GFP_KERNEL); if (!req) { mutex_unlock(tfm_mutex); printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " "skcipher_request_alloc for %s\n", __func__, crypto_skcipher_driver_name(tfm)); rc = -ENOMEM; goto out; } skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); rc = crypto_skcipher_setkey( 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; } skcipher_request_set_crypt(req, src_sg, dst_sg, auth_tok->session_key.encrypted_key_size, NULL); rc = crypto_skcipher_decrypt(req); 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: skcipher_request_free(req); 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_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 candidate 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 crypto_skcipher *tfm; struct skcipher_request *req; 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(&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) { printk(KERN_WARNING "No key size specified at mount; " "defaulting to [%d]\n", crypto_skcipher_max_keysize(tfm)); mount_crypt_stat->global_default_cipher_key_size = crypto_skcipher_max_keysize(tfm); } 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_skcipher_setkey(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; } req = skcipher_request_alloc(tfm, GFP_KERNEL); if (!req) { mutex_unlock(tfm_mutex); ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " "attempting to skcipher_request_alloc for " "%s\n", crypto_skcipher_driver_name(tfm)); rc = -ENOMEM; goto out; } skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); rc = 0; ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", crypt_stat->key_size); skcipher_request_set_crypt(req, src_sg, dst_sg, (*key_rec).enc_key_size, NULL); rc = crypto_skcipher_encrypt(req); mutex_unlock(tfm_mutex); skcipher_request_free(req); 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) 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; new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, GFP_KERNEL); if (!new_auth_tok) return -ENOMEM; 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); return 0; }
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