diff options
Diffstat (limited to 'fs/ecryptfs/keystore.c')
| -rw-r--r-- | fs/ecryptfs/keystore.c | 1078 |
1 files changed, 611 insertions, 467 deletions
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index b550dea8eee..89d9710dd63 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -39,7 +39,7 @@ * determine the type of error, make appropriate log entries, and * return an error code. */ -int process_request_key_err(long err_code) +static int process_request_key_err(long err_code) { int rc = 0; @@ -71,7 +71,7 @@ int process_request_key_err(long err_code) * address; zero on error * @length_size: The number of bytes occupied by the encoded length * - * Returns Zero on success + * Returns zero on success; non-zero on error */ static int parse_packet_length(unsigned char *data, size_t *size, size_t *length_size) @@ -106,11 +106,11 @@ out: /** * write_packet_length - * @dest: The byte array target into which to write the - * length. Must have at least 5 bytes allocated. + * @dest: The byte array target into which to write the length. Must + * have at least 5 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. + * @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. */ @@ -396,26 +396,53 @@ out: 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. + * 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. + * Returns zero on success; non-zero error otherwise. */ -static int decrypt_pki_encrypted_session_key( - struct ecryptfs_mount_crypt_stat *mount_crypt_stat, - struct ecryptfs_auth_tok *auth_tok, - struct ecryptfs_crypt_stat *crypt_stat) +static int +decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, + struct ecryptfs_crypt_stat *crypt_stat) { u16 cipher_code = 0; struct ecryptfs_msg_ctx *msg_ctx; struct ecryptfs_message *msg = NULL; + char *auth_tok_sig; char *netlink_message; size_t netlink_message_length; int rc; - rc = write_tag_64_packet(mount_crypt_stat->global_auth_tok_sig, - &(auth_tok->session_key), + 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), &netlink_message, &netlink_message_length); if (rc) { ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet"); @@ -465,40 +492,33 @@ out: static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) { - struct list_head *walker; struct ecryptfs_auth_tok_list_item *auth_tok_list_item; + struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; - walker = auth_tok_list_head->next; - while (walker != auth_tok_list_head) { - auth_tok_list_item = - list_entry(walker, struct ecryptfs_auth_tok_list_item, - list); - walker = auth_tok_list_item->list.next; - memset(auth_tok_list_item, 0, - sizeof(struct ecryptfs_auth_tok_list_item)); + 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); } - auth_tok_list_head->next = NULL; } struct kmem_cache *ecryptfs_auth_tok_list_item_cache; - /** * parse_tag_1_packet - * @crypt_stat: The cryptographic context to modify based on packet - * contents. + * @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. + * 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. */ @@ -515,72 +535,65 @@ parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, (*packet_size) = 0; (*new_auth_tok) = NULL; - - /* we check that: - * one byte for the Tag 1 ID flag - * two bytes for the body size - * do not exceed the maximum_packet_size + /** + * 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((*packet_size) + 3 > max_packet_size)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + if (unlikely(max_packet_size < 12)) { + printk(KERN_ERR "Invalid max packet size; must be >=12\n"); rc = -EINVAL; goto out; } - /* check for Tag 1 identifier - one byte */ if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { - ecryptfs_printk(KERN_ERR, "Enter w/ first byte != 0x%.2x\n", - 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_alloc(ecryptfs_auth_tok_list_item_cache, - GFP_KERNEL); + kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, + GFP_KERNEL); if (!auth_tok_list_item) { - ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); + printk(KERN_ERR "Unable to allocate memory\n"); rc = -ENOMEM; goto out; } - memset(auth_tok_list_item, 0, - sizeof(struct ecryptfs_auth_tok_list_item)); (*new_auth_tok) = &auth_tok_list_item->auth_tok; - /* check for body size - one to two bytes - * - * ***** TAG 1 Packet Format ***** - * | version number | 1 byte | - * | key ID | 8 bytes | - * | public key algorithm | 1 byte | - * | encrypted session key | arbitrary | - */ rc = parse_packet_length(&data[(*packet_size)], &body_size, &length_size); if (rc) { - ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " - "rc = [%d]\n", rc); + printk(KERN_WARNING "Error parsing packet length; " + "rc = [%d]\n", rc); goto out_free; } - if (unlikely(body_size < (0x02 + ECRYPTFS_SIG_SIZE))) { - ecryptfs_printk(KERN_WARNING, "Invalid body size ([%d])\n", - body_size); + 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)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + printk(KERN_WARNING "Packet size exceeds max\n"); rc = -EINVAL; goto out_free; } - /* Version 3 (from RFC2440) - one byte */ if (unlikely(data[(*packet_size)++] != 0x03)) { - ecryptfs_printk(KERN_DEBUG, "Unknown version number " - "[%d]\n", data[(*packet_size) - 1]); + printk(KERN_WARNING "Unknown version number [%d]\n", + data[(*packet_size) - 1]); rc = -EINVAL; goto out_free; } - /* Read Signature */ ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, &data[(*packet_size)], ECRYPTFS_SIG_SIZE); *packet_size += ECRYPTFS_SIG_SIZE; @@ -588,27 +601,23 @@ parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, * know which public key encryption algorithm was used */ (*packet_size)++; (*new_auth_tok)->session_key.encrypted_key_size = - body_size - (0x02 + ECRYPTFS_SIG_SIZE); + body_size - (ECRYPTFS_SIG_SIZE + 2); if ((*new_auth_tok)->session_key.encrypted_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { - ecryptfs_printk(KERN_ERR, "Tag 1 packet contains key larger " - "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); + printk(KERN_WARNING "Tag 1 packet contains key larger " + "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES"); rc = -EINVAL; goto out; } - ecryptfs_printk(KERN_DEBUG, "Encrypted key size = [%d]\n", - (*new_auth_tok)->session_key.encrypted_key_size); memcpy((*new_auth_tok)->session_key.encrypted_key, - &data[(*packet_size)], (body_size - 0x02 - ECRYPTFS_SIG_SIZE)); + &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 |= ECRYPTFS_PRIVATE_KEY; - /* TODO: Why are we setting this flag here? Don't we want the - * userspace to decrypt the session key? */ + (*new_auth_tok)->flags = 0; (*new_auth_tok)->session_key.flags &= ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); (*new_auth_tok)->session_key.flags &= @@ -658,22 +667,30 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, (*packet_size) = 0; (*new_auth_tok) = NULL; - - /* we check that: - * one byte for the Tag 3 ID flag - * two bytes for the body size - * do not exceed the maximum_packet_size + /** + *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 (unlikely((*packet_size) + 3 > max_packet_size)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { + printk(KERN_ERR "Max packet size too large\n"); rc = -EINVAL; goto out; } - - /* check for Tag 3 identifyer - one byte */ if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { - ecryptfs_printk(KERN_ERR, "Enter w/ first byte != 0x%.2x\n", - ECRYPTFS_TAG_3_PACKET_TYPE); + printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", + ECRYPTFS_TAG_3_PACKET_TYPE); rc = -EINVAL; goto out; } @@ -682,56 +699,37 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, auth_tok_list_item = kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); if (!auth_tok_list_item) { - ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); + printk(KERN_ERR "Unable to allocate memory\n"); rc = -ENOMEM; goto out; } (*new_auth_tok) = &auth_tok_list_item->auth_tok; - - /* check for body size - one to two bytes */ rc = parse_packet_length(&data[(*packet_size)], &body_size, &length_size); if (rc) { - ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " - "rc = [%d]\n", rc); + printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", + rc); goto out_free; } - if (unlikely(body_size < (0x05 + ECRYPTFS_SALT_SIZE))) { - ecryptfs_printk(KERN_WARNING, "Invalid body size ([%d])\n", - body_size); + 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; - - /* now we know the length of the remainting Tag 3 packet size: - * 5 fix bytes for: version string, cipher, S2K ID, hash algo, - * number of hash iterations - * ECRYPTFS_SALT_SIZE bytes for salt - * body_size bytes minus the stuff above is the encrypted key size - */ if (unlikely((*packet_size) + body_size > max_packet_size)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + printk(KERN_ERR "Packet size exceeds max\n"); rc = -EINVAL; goto out_free; } - - /* There are 5 characters of additional information in the - * packet */ (*new_auth_tok)->session_key.encrypted_key_size = - body_size - (0x05 + ECRYPTFS_SALT_SIZE); - ecryptfs_printk(KERN_DEBUG, "Encrypted key size = [%d]\n", - (*new_auth_tok)->session_key.encrypted_key_size); - - /* Version 4 (from RFC2440) - one byte */ + (body_size - (ECRYPTFS_SALT_SIZE + 5)); if (unlikely(data[(*packet_size)++] != 0x04)) { - ecryptfs_printk(KERN_DEBUG, "Unknown version number " - "[%d]\n", data[(*packet_size) - 1]); + printk(KERN_WARNING "Unknown version number [%d]\n", + data[(*packet_size) - 1]); rc = -EINVAL; goto out_free; } - - /* cipher - one byte */ ecryptfs_cipher_code_to_string(crypt_stat->cipher, (u16)data[(*packet_size)]); /* A little extra work to differentiate among the AES key @@ -745,33 +743,26 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, (*new_auth_tok)->session_key.encrypted_key_size; } ecryptfs_init_crypt_ctx(crypt_stat); - /* S2K identifier 3 (from RFC2440) */ if (unlikely(data[(*packet_size)++] != 0x03)) { - ecryptfs_printk(KERN_ERR, "Only S2K ID 3 is currently " - "supported\n"); + printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); rc = -ENOSYS; goto out_free; } - /* TODO: finish the hash mapping */ - /* hash algorithm - one byte */ switch (data[(*packet_size)++]) { case 0x01: /* See RFC2440 for these numbers and their mappings */ /* Choose MD5 */ - /* salt - ECRYPTFS_SALT_SIZE bytes */ 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 */ - /* number of hash iterations - one byte */ (*new_auth_tok)->token.password.hash_iterations = ((u32) 16 + (data[(*packet_size)] & 15)) << ((data[(*packet_size)] >> 4) + 6); (*packet_size)++; - - /* encrypted session key - - * (body_size-5-ECRYPTFS_SALT_SIZE) bytes */ + /* 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); @@ -781,7 +772,7 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, ~ECRYPTFS_CONTAINS_DECRYPTED_KEY; (*new_auth_tok)->session_key.flags |= ECRYPTFS_CONTAINS_ENCRYPTED_KEY; - (*new_auth_tok)->token.password.hash_algo = 0x01; + (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ break; default: ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " @@ -837,82 +828,61 @@ parse_tag_11_packet(unsigned char *data, unsigned char *contents, (*packet_size) = 0; (*tag_11_contents_size) = 0; - - /* check that: - * one byte for the Tag 11 ID flag - * two bytes for the Tag 11 length - * do not exceed the maximum_packet_size + /* 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 (unlikely((*packet_size) + 3 > max_packet_size)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + if (max_packet_size < 16) { + printk(KERN_ERR "Maximum packet size too small\n"); rc = -EINVAL; goto out; } - - /* check for Tag 11 identifyer - one byte */ if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { - ecryptfs_printk(KERN_WARNING, - "Invalid tag 11 packet format\n"); + printk(KERN_WARNING "Invalid tag 11 packet format\n"); rc = -EINVAL; goto out; } - - /* get Tag 11 content length - one or two bytes */ rc = parse_packet_length(&data[(*packet_size)], &body_size, &length_size); if (rc) { - ecryptfs_printk(KERN_WARNING, - "Invalid tag 11 packet format\n"); + printk(KERN_WARNING "Invalid tag 11 packet format\n"); goto out; } - (*packet_size) += length_size; - - if (body_size < 13) { - ecryptfs_printk(KERN_WARNING, "Invalid body size ([%d])\n", - body_size); + if (body_size < 14) { + printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); rc = -EINVAL; goto out; } - /* We have 13 bytes of surrounding packet values */ - (*tag_11_contents_size) = (body_size - 13); - - /* now we know the length of the remainting Tag 11 packet size: - * 14 fix bytes for: special flag one, special flag two, - * 12 skipped bytes - * body_size bytes minus the stuff above is the Tag 11 content - */ - /* FIXME why is the body size one byte smaller than the actual - * size of the body? - * this seems to be an error here as well as in - * write_tag_11_packet() */ + (*packet_size) += length_size; + (*tag_11_contents_size) = (body_size - 14); if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { - ecryptfs_printk(KERN_ERR, "Packet size exceeds max\n"); + printk(KERN_ERR "Packet size exceeds max\n"); rc = -EINVAL; goto out; } - - /* special flag one - one byte */ if (data[(*packet_size)++] != 0x62) { - ecryptfs_printk(KERN_WARNING, "Unrecognizable packet\n"); + printk(KERN_WARNING "Unrecognizable packet\n"); rc = -EINVAL; goto out; } - - /* special flag two - one byte */ if (data[(*packet_size)++] != 0x08) { - ecryptfs_printk(KERN_WARNING, "Unrecognizable packet\n"); + printk(KERN_WARNING "Unrecognizable packet\n"); rc = -EINVAL; goto out; } - - /* skip the next 12 bytes */ - (*packet_size) += 12; /* We don't care about the filename or - * the timestamp */ - - /* get the Tag 11 contents - tag_11_contents_size bytes */ + (*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; @@ -921,130 +891,229 @@ out: return rc; } +static int +ecryptfs_find_global_auth_tok_for_sig( + struct ecryptfs_global_auth_tok **global_auth_tok, + struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) +{ + struct ecryptfs_global_auth_tok *walker; + int rc = 0; + + (*global_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) == 0) { + (*global_auth_tok) = walker; + goto out; + } + } + rc = -EINVAL; +out: + mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); + return rc; +} + /** - * decrypt_session_key - Decrypt the session key with the given auth_tok. + * ecryptfs_verify_version + * @version: The version number to confirm * - * Returns Zero on success; non-zero error otherwise. + * Returns zero on good version; non-zero otherwise */ -static int decrypt_session_key(struct ecryptfs_auth_tok *auth_tok, - struct ecryptfs_crypt_stat *crypt_stat) +static int ecryptfs_verify_version(u16 version) { - struct ecryptfs_password *password_s_ptr; - struct scatterlist src_sg[2], dst_sg[2]; - struct mutex *tfm_mutex = NULL; - char *encrypted_session_key; - char *session_key; + 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; +} + +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)) { + printk(KERN_ERR "Could not find key with description: [%s]\n", + sig); + process_request_key_err(PTR_ERR(*auth_tok_key)); + rc = -EINVAL; + goto out; + } + (*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; +} + +/** + * 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 ecryptfs_auth_tok **auth_tok, + struct ecryptfs_crypt_stat *crypt_stat, char *sig) +{ + struct ecryptfs_mount_crypt_stat *mount_crypt_stat = + crypt_stat->mount_crypt_stat; + struct ecryptfs_global_auth_tok *global_auth_tok; + int rc = 0; + + (*auth_tok) = NULL; + if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok, + mount_crypt_stat, sig)) { + struct key *auth_tok_key; + + rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok, + sig); + } else + (*auth_tok) = global_auth_tok->global_auth_tok; + 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; + struct scatterlist src_sg; + struct mutex *tfm_mutex; struct blkcipher_desc desc = { .flags = CRYPTO_TFM_REQ_MAY_SLEEP }; int rc = 0; - password_s_ptr = &auth_tok->token.password; - if (password_s_ptr->flags & ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) - ecryptfs_printk(KERN_DEBUG, "Session key encryption key " - "set; skipping key generation\n"); - ecryptfs_printk(KERN_DEBUG, "Session key encryption key (size [%d])" - ":\n", - password_s_ptr->session_key_encryption_key_bytes); - if (ecryptfs_verbosity > 0) - ecryptfs_dump_hex(password_s_ptr->session_key_encryption_key, - password_s_ptr-> - session_key_encryption_key_bytes); - if (!strcmp(crypt_stat->cipher, - crypt_stat->mount_crypt_stat->global_default_cipher_name) - && crypt_stat->mount_crypt_stat->global_key_tfm) { - desc.tfm = crypt_stat->mount_crypt_stat->global_key_tfm; - tfm_mutex = &crypt_stat->mount_crypt_stat->global_key_tfm_mutex; - } else { - char *full_alg_name; - - rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, - crypt_stat->cipher, - "ecb"); - if (rc) - goto out; - desc.tfm = crypto_alloc_blkcipher(full_alg_name, 0, - CRYPTO_ALG_ASYNC); - kfree(full_alg_name); - if (IS_ERR(desc.tfm)) { - rc = PTR_ERR(desc.tfm); - printk(KERN_ERR "Error allocating crypto context; " - "rc = [%d]\n", rc); - goto out; - } - crypto_blkcipher_set_flags(desc.tfm, CRYPTO_TFM_REQ_WEAK_KEY); + 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; } - if (tfm_mutex) - mutex_lock(tfm_mutex); - rc = crypto_blkcipher_setkey(desc.tfm, - password_s_ptr->session_key_encryption_key, - crypt_stat->key_size); - if (rc < 0) { + rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, + auth_tok->session_key.encrypted_key_size, + &src_sg, 1); + if (rc != 1) { + 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, 1); + if (rc != 1) { + 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_free_tfm; - } - /* TODO: virt_to_scatterlist */ - encrypted_session_key = (char *)__get_free_page(GFP_KERNEL); - if (!encrypted_session_key) { - ecryptfs_printk(KERN_ERR, "Out of memory\n"); - rc = -ENOMEM; - goto out_free_tfm; + goto out; } - session_key = (char *)__get_free_page(GFP_KERNEL); - if (!session_key) { - kfree(encrypted_session_key); - ecryptfs_printk(KERN_ERR, "Out of memory\n"); - rc = -ENOMEM; - goto out_free_tfm; - } - memcpy(encrypted_session_key, auth_tok->session_key.encrypted_key, - auth_tok->session_key.encrypted_key_size); - src_sg[0].page = virt_to_page(encrypted_session_key); - src_sg[0].offset = 0; - BUG_ON(auth_tok->session_key.encrypted_key_size > PAGE_CACHE_SIZE); - src_sg[0].length = auth_tok->session_key.encrypted_key_size; - dst_sg[0].page = virt_to_page(session_key); - dst_sg[0].offset = 0; - auth_tok->session_key.decrypted_key_size = - auth_tok->session_key.encrypted_key_size; - dst_sg[0].length = auth_tok->session_key.encrypted_key_size; - rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, + rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg, auth_tok->session_key.encrypted_key_size); - if (rc) { + mutex_unlock(tfm_mutex); + if (unlikely(rc)) { printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); - goto out_free_memory; + goto out; } - auth_tok->session_key.decrypted_key_size = - auth_tok->session_key.encrypted_key_size; - memcpy(auth_tok->session_key.decrypted_key, session_key, - auth_tok->session_key.decrypted_key_size); 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; - ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); - if (ecryptfs_verbosity > 0) + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n", + crypt_stat->key_size); ecryptfs_dump_hex(crypt_stat->key, crypt_stat->key_size); -out_free_memory: - memset(encrypted_session_key, 0, PAGE_CACHE_SIZE); - free_page((unsigned long)encrypted_session_key); - memset(session_key, 0, PAGE_CACHE_SIZE); - free_page((unsigned long)session_key); -out_free_tfm: - if (tfm_mutex) - mutex_unlock(tfm_mutex); - else - crypto_free_blkcipher(desc.tfm); + } out: return rc; } /** * ecryptfs_parse_packet_set - * @dest: The header page in memory - * @version: Version of file format, to guide parsing behavior + * @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. @@ -1058,25 +1127,22 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, struct dentry *ecryptfs_dentry) { size_t i = 0; - size_t found_auth_tok = 0; + size_t found_auth_tok; size_t next_packet_is_auth_tok_packet; - char sig[ECRYPTFS_SIG_SIZE_HEX]; struct list_head auth_tok_list; - struct list_head *walker; - struct ecryptfs_auth_tok *chosen_auth_tok = NULL; - struct ecryptfs_mount_crypt_stat *mount_crypt_stat = - &ecryptfs_superblock_to_private( - ecryptfs_dentry->d_sb)->mount_crypt_stat; - struct ecryptfs_auth_tok *candidate_auth_tok = NULL; + 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; int rc = 0; INIT_LIST_HEAD(&auth_tok_list); - /* Parse the header to find as many packets as we can, these will be + /* 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) { @@ -1155,73 +1221,85 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, } } if (list_empty(&auth_tok_list)) { - rc = -EINVAL; /* Do not support non-encrypted files in - * the 0.1 release */ + 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; } - /* If we have a global auth tok, then we should try to use - * it */ - if (mount_crypt_stat->global_auth_tok) { - memcpy(sig, mount_crypt_stat->global_auth_tok_sig, - ECRYPTFS_SIG_SIZE_HEX); - chosen_auth_tok = mount_crypt_stat->global_auth_tok; - } else - BUG(); /* We should always have a global auth tok in - * the 0.1 release */ - /* Scan list to see if our chosen_auth_tok works */ - list_for_each(walker, &auth_tok_list) { - struct ecryptfs_auth_tok_list_item *auth_tok_list_item; - auth_tok_list_item = - list_entry(walker, struct ecryptfs_auth_tok_list_item, - list); + /* 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); } - /* TODO: Replace ECRYPTFS_SIG_SIZE_HEX w/ dynamic value */ - if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD - && !strncmp(candidate_auth_tok->token.password.signature, - sig, ECRYPTFS_SIG_SIZE_HEX)) { - found_auth_tok = 1; - goto leave_list; - /* TODO: Transfer the common salt into the - * crypt_stat salt */ - } else if ((candidate_auth_tok->token_type - == ECRYPTFS_PRIVATE_KEY) - && !strncmp(candidate_auth_tok->token.private_key.signature, - sig, ECRYPTFS_SIG_SIZE_HEX)) { + 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; + } + ecryptfs_find_auth_tok_for_sig(&matching_auth_tok, crypt_stat, + candidate_auth_tok_sig); + if (matching_auth_tok) { found_auth_tok = 1; - goto leave_list; + goto found_matching_auth_tok; } } if (!found_auth_tok) { - ecryptfs_printk(KERN_ERR, "Could not find authentication " - "token on temporary list for sig [%.*s]\n", - ECRYPTFS_SIG_SIZE_HEX, sig); + ecryptfs_printk(KERN_ERR, "Could not find a usable " + "authentication token\n"); rc = -EIO; goto out_wipe_list; } -leave_list: - rc = -ENOTSUPP; +found_matching_auth_tok: if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { memcpy(&(candidate_auth_tok->token.private_key), - &(chosen_auth_tok->token.private_key), + &(matching_auth_tok->token.private_key), sizeof(struct ecryptfs_private_key)); - rc = decrypt_pki_encrypted_session_key(mount_crypt_stat, - candidate_auth_tok, + 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), - &(chosen_auth_tok->token.password), + &(matching_auth_tok->token.password), sizeof(struct ecryptfs_password)); - rc = decrypt_session_key(candidate_auth_tok, crypt_stat); + rc = decrypt_passphrase_encrypted_session_key( + candidate_auth_tok, crypt_stat); } if (rc) { - ecryptfs_printk(KERN_ERR, "Error decrypting the " - "session key; rc = [%d]\n", rc); - goto out_wipe_list; + 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", candidate_auth_tok_sig, + ECRYPTFS_SIG_SIZE_HEX, 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) { @@ -1240,6 +1318,7 @@ out_wipe_list: out: return rc; } + static int pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok, struct ecryptfs_crypt_stat *crypt_stat, @@ -1284,22 +1363,25 @@ out: /** * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet * @dest: Buffer into which to write the packet - * @max: Maximum number of bytes that can be writtn + * @remaining_bytes: Maximum number of bytes that can be writtn + * @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 max, struct ecryptfs_auth_tok *auth_tok, +write_tag_1_packet(char *dest, size_t *remaining_bytes, + struct ecryptfs_auth_tok *auth_tok, struct ecryptfs_crypt_stat *crypt_stat, - struct ecryptfs_mount_crypt_stat *mount_crypt_stat, struct ecryptfs_key_record *key_rec, size_t *packet_size) { size_t i; size_t encrypted_session_key_valid = 0; - size_t key_rec_size; size_t packet_size_length; + size_t max_packet_size; int rc = 0; (*packet_size) = 0; @@ -1329,37 +1411,23 @@ write_tag_1_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); } encrypted_session_key_set: - /* Now we have a valid key_rec. Append it to the - * key_rec set. */ - key_rec_size = (sizeof(struct ecryptfs_key_record) - - ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES - + (key_rec->enc_key_size)); - /* TODO: Include a packet size limit as a parameter to this - * function once we have multi-packet headers (for versions - * later than 0.1 */ - if (key_rec_size >= ECRYPTFS_MAX_KEYSET_SIZE) { - ecryptfs_printk(KERN_ERR, "Keyset too large\n"); - rc = -EINVAL; - goto out; - } - /* ***** TAG 1 Packet Format ***** - * | version number | 1 byte | - * | key ID | 8 bytes | - * | public key algorithm | 1 byte | - * | encrypted session key | arbitrary | - */ - if ((0x02 + ECRYPTFS_SIG_SIZE + key_rec->enc_key_size) >= max) { - ecryptfs_printk(KERN_ERR, - "Authentication token is too large\n"); + /* 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; - /* This format is inspired by OpenPGP; see RFC 2440 - * packet tag 1 */ - rc = write_packet_length(&dest[(*packet_size)], - (0x02 + ECRYPTFS_SIG_SIZE + - key_rec->enc_key_size), + rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4), &packet_size_length); if (rc) { ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " @@ -1377,13 +1445,15 @@ encrypted_session_key_set: 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 - * @max: Maximum packet length + * @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 @@ -1391,54 +1461,59 @@ out: * Returns zero on success; non-zero on error. */ static int -write_tag_11_packet(char *dest, int max, char *contents, size_t contents_length, - size_t *packet_length) +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; - if ((13 + contents_length) > max) { + /* 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; - ecryptfs_printk(KERN_ERR, "Packet length larger than " - "maximum allowable\n"); goto out; } - /* General packet header */ - /* Packet tag */ dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; - /* Packet length */ rc = write_packet_length(&dest[(*packet_length)], - (13 + contents_length), &packet_size_length); + (max_packet_size - 4), &packet_size_length); if (rc) { - ecryptfs_printk(KERN_ERR, "Error generating tag 11 packet " - "header; cannot generate packet length\n"); + printk(KERN_ERR "Error generating tag 11 packet header; cannot " + "generate packet length. rc = [%d]\n", rc); goto out; } (*packet_length) += packet_size_length; - /* Tag 11 specific */ - /* One-octet field that describes how the data is formatted */ - dest[(*packet_length)++] = 0x62; /* binary data */ - /* One-octet filename length followed by filename */ + dest[(*packet_length)++] = 0x62; /* binary data format specifier */ dest[(*packet_length)++] = 8; memcpy(&dest[(*packet_length)], "_CONSOLE", 8); (*packet_length) += 8; - /* Four-octet number indicating modification date */ memset(&dest[(*packet_length)], 0x00, 4); (*packet_length) += 4; - /* Remainder is literal data */ 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 - * @max: Maximum number of bytes that can be written + * @remaining_bytes: Maximum number of bytes that can be written * @auth_tok: Authentication token * @crypt_stat: The cryptographic context * @key_rec: encrypted key @@ -1448,19 +1523,22 @@ write_tag_11_packet(char *dest, int max, char *contents, size_t contents_length, * Returns zero on success; non-zero on error. */ static int -write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, +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 dest_sg[2]; - struct scatterlist src_sg[2]; + struct scatterlist dst_sg; + struct scatterlist src_sg; struct mutex *tfm_mutex = NULL; - size_t key_rec_size; - size_t packet_size_length; size_t 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 @@ -1470,16 +1548,25 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, (*packet_size) = 0; ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.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); - goto encrypted_session_key_set; + 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; @@ -1487,9 +1574,24 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, && 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 = [%d]\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 " @@ -1508,54 +1610,32 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, 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) { + rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, + &src_sg, 1); + if (rc != 1) { ecryptfs_printk(KERN_ERR, "Error generating scatterlist " - "for crypt_stat session key\n"); + "for crypt_stat session key; expected rc = 1; " + "got rc = [%d]. key_rec->enc_key_size = [%d]\n", + rc, key_rec->enc_key_size); rc = -ENOMEM; goto out; } - rc = virt_to_scatterlist(key_rec->enc_key, - key_rec->enc_key_size, dest_sg, 2); - if (!rc) { + rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, + &dst_sg, 1); + if (rc != 1) { ecryptfs_printk(KERN_ERR, "Error generating scatterlist " - "for crypt_stat encrypted session key\n"); + "for crypt_stat encrypted session key; " + "expected rc = 1; got rc = [%d]. " + "key_rec->enc_key_size = [%d]\n", rc, + key_rec->enc_key_size); rc = -ENOMEM; goto out; } - if (!strcmp(crypt_stat->cipher, - crypt_stat->mount_crypt_stat->global_default_cipher_name) - && crypt_stat->mount_crypt_stat->global_key_tfm) { - desc.tfm = crypt_stat->mount_crypt_stat->global_key_tfm; - tfm_mutex = &crypt_stat->mount_crypt_stat->global_key_tfm_mutex; - } else { - char *full_alg_name; - - rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, - crypt_stat->cipher, - "ecb"); - if (rc) - goto out; - desc.tfm = crypto_alloc_blkcipher(full_alg_name, 0, - CRYPTO_ALG_ASYNC); - kfree(full_alg_name); - if (IS_ERR(desc.tfm)) { - rc = PTR_ERR(desc.tfm); - ecryptfs_printk(KERN_ERR, "Could not initialize crypto " - "context for cipher [%s]; rc = [%d]\n", - crypt_stat->cipher, rc); - goto out; - } - crypto_blkcipher_set_flags(desc.tfm, CRYPTO_TFM_REQ_WEAK_KEY); - } - if (tfm_mutex) - mutex_lock(tfm_mutex); + mutex_lock(tfm_mutex); rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key, crypt_stat->key_size); if (rc < 0) { - if (tfm_mutex) - mutex_unlock(tfm_mutex); + mutex_unlock(tfm_mutex); ecryptfs_printk(KERN_ERR, "Error setting key for crypto " "context; rc = [%d]\n", rc); goto out; @@ -1563,56 +1643,53 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok, rc = 0; ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n", crypt_stat->key_size); - rc = crypto_blkcipher_encrypt(&desc, dest_sg, src_sg, + 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; } - if (tfm_mutex) - mutex_unlock(tfm_mutex); ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); - if (ecryptfs_verbosity > 0) + if (ecryptfs_verbosity > 0) { + ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n", + key_rec->enc_key_size); ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); -encrypted_session_key_set: - /* Now we have a valid key_rec. Append it to the - * key_rec set. */ - key_rec_size = (sizeof(struct ecryptfs_key_record) - - ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES - + (key_rec->enc_key_size)); - /* TODO: Include a packet size limit as a parameter to this - * function once we have multi-packet headers (for versions - * later than 0.1 */ - if (key_rec_size >= ECRYPTFS_MAX_KEYSET_SIZE) { - ecryptfs_printk(KERN_ERR, "Keyset too large\n"); - rc = -EINVAL; - goto out; } - /* TODO: Packet size limit */ - /* We have 5 bytes of surrounding packet data */ - if ((0x05 + ECRYPTFS_SALT_SIZE - + key_rec->enc_key_size) >= max) { - ecryptfs_printk(KERN_ERR, "Authentication token is too " - "large\n"); +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; } - /* This format is inspired by OpenPGP; see RFC 2440 - * packet tag 3 */ dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; - /* ver+cipher+s2k+hash+salt+iter+enc_key */ - rc = write_packet_length(&dest[(*packet_size)], - (0x05 + ECRYPTFS_SALT_SIZE - + key_rec->enc_key_size), + /* 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 = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4), &packet_size_length); if (rc) { - ecryptfs_printk(KERN_ERR, "Error generating tag 3 packet " - "header; cannot generate packet length\n"); + 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); if (cipher_code == 0) { ecryptfs_printk(KERN_WARNING, "Unable to generate code for " @@ -1631,10 +1708,10 @@ encrypted_session_key_set: key_rec->enc_key_size); (*packet_size) += key_rec->enc_key_size; out: - if (desc.tfm && !tfm_mutex) - crypto_free_blkcipher(desc.tfm); if (rc) (*packet_size) = 0; + else + (*remaining_bytes) -= (*packet_size); return rc; } @@ -1642,7 +1719,7 @@ struct kmem_cache *ecryptfs_key_record_cache; /** * ecryptfs_generate_key_packet_set - * @dest: Virtual address from which to write the key record 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 @@ -1662,24 +1739,43 @@ ecryptfs_generate_key_packet_set(char *dest_base, size_t max) { struct ecryptfs_auth_tok *auth_tok; + struct ecryptfs_global_auth_tok *global_auth_tok; 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; } - if (mount_crypt_stat->global_auth_tok) { - auth_tok = mount_crypt_stat->global_auth_tok; + 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(&global_auth_tok, + mount_crypt_stat, + key_sig->keysig); + if (rc) { + printk(KERN_ERR "Error attempting to get the global " + "auth_tok; rc = [%d]\n", rc); + goto out_free; + } + if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) { + printk(KERN_WARNING + "Skipping invalid auth tok with sig = [%s]\n", + global_auth_tok->sig); + continue; + } + auth_tok = global_auth_tok->global_auth_tok; if (auth_tok->token_type == ECRYPTFS_PASSWORD) { rc = write_tag_3_packet((dest_base + (*len)), - max, auth_tok, + &max, auth_tok, crypt_stat, key_rec, &written); if (rc) { @@ -1689,10 +1785,9 @@ ecryptfs_generate_key_packet_set(char *dest_base, } (*len) += written; /* Write auth tok signature packet */ - rc = write_tag_11_packet( - (dest_base + (*len)), - (max - (*len)), - key_rec->sig, ECRYPTFS_SIG_SIZE, &written); + 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"); @@ -1701,9 +1796,8 @@ ecryptfs_generate_key_packet_set(char *dest_base, (*len) += written; } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { rc = write_tag_1_packet(dest_base + (*len), - max, auth_tok, - crypt_stat,mount_crypt_stat, - key_rec, &written); + &max, auth_tok, + crypt_stat, key_rec, &written); if (rc) { ecryptfs_printk(KERN_WARNING, "Error " "writing tag 1 packet\n"); @@ -1716,19 +1810,69 @@ ecryptfs_generate_key_packet_set(char *dest_base, rc = -EINVAL; goto out_free; } - } else - BUG(); - if (likely((max - (*len)) > 0)) { + } + 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; + int rc = 0; + + new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); + if (!new_key_sig) { + rc = -ENOMEM; + printk(KERN_ERR + "Error allocating from ecryptfs_key_sig_cache\n"); + goto out; + } + memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); + mutex_lock(&crypt_stat->keysig_list_mutex); + list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); + mutex_unlock(&crypt_stat->keysig_list_mutex); +out: + return rc; +} + +struct kmem_cache *ecryptfs_global_auth_tok_cache; + +int +ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, + char *sig) +{ + struct ecryptfs_global_auth_tok *new_auth_tok; + int rc = 0; + + new_auth_tok = kmem_cache_alloc(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->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); + mount_crypt_stat->num_global_auth_toks++; + mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); +out: + return rc; +} + |