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/*
* TLSv1 Record Protocol
* Copyright (c) 2006-2011, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/md5.h"
#include "crypto/sha1.h"
#include "crypto/sha256.h"
#include "tlsv1_common.h"
#include "tlsv1_record.h"
/**
* tlsv1_record_set_cipher_suite - TLS record layer: Set cipher suite
* @rl: Pointer to TLS record layer data
* @cipher_suite: New cipher suite
* Returns: 0 on success, -1 on failure
*
* This function is used to prepare TLS record layer for cipher suite change.
* tlsv1_record_change_write_cipher() and
* tlsv1_record_change_read_cipher() functions can then be used to change the
* currently used ciphers.
*/
int tlsv1_record_set_cipher_suite(struct tlsv1_record_layer *rl,
u16 cipher_suite)
{
const struct tls_cipher_suite *suite;
const struct tls_cipher_data *data;
wpa_printf(MSG_DEBUG, "TLSv1: Selected cipher suite: 0x%04x",
cipher_suite);
rl->cipher_suite = cipher_suite;
suite = tls_get_cipher_suite(cipher_suite);
if (suite == NULL)
return -1;
if (suite->hash == TLS_HASH_MD5) {
rl->hash_alg = CRYPTO_HASH_ALG_HMAC_MD5;
rl->hash_size = MD5_MAC_LEN;
} else if (suite->hash == TLS_HASH_SHA) {
rl->hash_alg = CRYPTO_HASH_ALG_HMAC_SHA1;
rl->hash_size = SHA1_MAC_LEN;
} else if (suite->hash == TLS_HASH_SHA256) {
rl->hash_alg = CRYPTO_HASH_ALG_HMAC_SHA256;
rl->hash_size = SHA256_MAC_LEN;
}
data = tls_get_cipher_data(suite->cipher);
if (data == NULL)
return -1;
rl->key_material_len = data->key_material;
rl->iv_size = data->block_size;
rl->cipher_alg = data->alg;
return 0;
}
/**
* tlsv1_record_change_write_cipher - TLS record layer: Change write cipher
* @rl: Pointer to TLS record layer data
* Returns: 0 on success (cipher changed), -1 on failure
*
* This function changes TLS record layer to use the new cipher suite
* configured with tlsv1_record_set_cipher_suite() for writing.
*/
int tlsv1_record_change_write_cipher(struct tlsv1_record_layer *rl)
{
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - New write cipher suite "
"0x%04x", rl->cipher_suite);
rl->write_cipher_suite = rl->cipher_suite;
os_memset(rl->write_seq_num, 0, TLS_SEQ_NUM_LEN);
if (rl->write_cbc) {
crypto_cipher_deinit(rl->write_cbc);
rl->write_cbc = NULL;
}
if (rl->cipher_alg != CRYPTO_CIPHER_NULL) {
rl->write_cbc = crypto_cipher_init(rl->cipher_alg,
rl->write_iv, rl->write_key,
rl->key_material_len);
if (rl->write_cbc == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize "
"cipher");
return -1;
}
}
return 0;
}
/**
* tlsv1_record_change_read_cipher - TLS record layer: Change read cipher
* @rl: Pointer to TLS record layer data
* Returns: 0 on success (cipher changed), -1 on failure
*
* This function changes TLS record layer to use the new cipher suite
* configured with tlsv1_record_set_cipher_suite() for reading.
*/
int tlsv1_record_change_read_cipher(struct tlsv1_record_layer *rl)
{
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - New read cipher suite "
"0x%04x", rl->cipher_suite);
rl->read_cipher_suite = rl->cipher_suite;
os_memset(rl->read_seq_num, 0, TLS_SEQ_NUM_LEN);
if (rl->read_cbc) {
crypto_cipher_deinit(rl->read_cbc);
rl->read_cbc = NULL;
}
if (rl->cipher_alg != CRYPTO_CIPHER_NULL) {
rl->read_cbc = crypto_cipher_init(rl->cipher_alg,
rl->read_iv, rl->read_key,
rl->key_material_len);
if (rl->read_cbc == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize "
"cipher");
return -1;
}
}
return 0;
}
/**
* tlsv1_record_send - TLS record layer: Send a message
* @rl: Pointer to TLS record layer data
* @content_type: Content type (TLS_CONTENT_TYPE_*)
* @buf: Buffer for the generated TLS message (needs to have extra space for
* header, IV (TLS v1.1), and HMAC)
* @buf_size: Maximum buf size
* @payload: Payload to be sent
* @payload_len: Length of the payload
* @out_len: Buffer for returning the used buf length
* Returns: 0 on success, -1 on failure
*
* This function fills in the TLS record layer header, adds HMAC, and encrypts
* the data using the current write cipher.
*/
int tlsv1_record_send(struct tlsv1_record_layer *rl, u8 content_type, u8 *buf,
size_t buf_size, const u8 *payload, size_t payload_len,
size_t *out_len)
{
u8 *pos, *ct_start, *length, *cpayload;
struct crypto_hash *hmac;
size_t clen;
int explicit_iv;
pos = buf;
if (pos + TLS_RECORD_HEADER_LEN > buf + buf_size)
return -1;
/* ContentType type */
ct_start = pos;
*pos++ = content_type;
/* ProtocolVersion version */
WPA_PUT_BE16(pos, rl->tls_version);
pos += 2;
/* uint16 length */
length = pos;
WPA_PUT_BE16(length, payload_len);
pos += 2;
cpayload = pos;
explicit_iv = rl->write_cipher_suite != TLS_NULL_WITH_NULL_NULL &&
rl->iv_size && rl->tls_version >= TLS_VERSION_1_1;
if (explicit_iv) {
/* opaque IV[Cipherspec.block_length] */
if (pos + rl->iv_size > buf + buf_size)
return -1;
/*
* Use random number R per the RFC 4346, 6.2.3.2 CBC Block
* Cipher option 2a.
*/
if (os_get_random(pos, rl->iv_size))
return -1;
pos += rl->iv_size;
}
/*
* opaque fragment[TLSPlaintext.length]
* (opaque content[TLSCompressed.length] in GenericBlockCipher)
*/
if (pos + payload_len > buf + buf_size)
return -1;
os_memmove(pos, payload, payload_len);
pos += payload_len;
if (rl->write_cipher_suite != TLS_NULL_WITH_NULL_NULL) {
/*
* MAC calculated over seq_num + TLSCompressed.type +
* TLSCompressed.version + TLSCompressed.length +
* TLSCompressed.fragment
*/
hmac = crypto_hash_init(rl->hash_alg, rl->write_mac_secret,
rl->hash_size);
if (hmac == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
"to initialize HMAC");
return -1;
}
crypto_hash_update(hmac, rl->write_seq_num, TLS_SEQ_NUM_LEN);
/* type + version + length + fragment */
crypto_hash_update(hmac, ct_start, TLS_RECORD_HEADER_LEN);
crypto_hash_update(hmac, payload, payload_len);
clen = buf + buf_size - pos;
if (clen < rl->hash_size) {
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Not "
"enough room for MAC");
crypto_hash_finish(hmac, NULL, NULL);
return -1;
}
if (crypto_hash_finish(hmac, pos, &clen) < 0) {
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
"to calculate HMAC");
return -1;
}
wpa_hexdump(MSG_MSGDUMP, "TLSv1: Record Layer - Write HMAC",
pos, clen);
pos += clen;
if (rl->iv_size) {
size_t len = pos - cpayload;
size_t pad;
pad = (len + 1) % rl->iv_size;
if (pad)
pad = rl->iv_size - pad;
if (pos + pad + 1 > buf + buf_size) {
wpa_printf(MSG_DEBUG, "TLSv1: No room for "
"block cipher padding");
return -1;
}
os_memset(pos, pad, pad + 1);
pos += pad + 1;
}
if (crypto_cipher_encrypt(rl->write_cbc, cpayload,
cpayload, pos - cpayload) < 0)
return -1;
}
WPA_PUT_BE16(length, pos - length - 2);
inc_byte_array(rl->write_seq_num, TLS_SEQ_NUM_LEN);
*out_len = pos - buf;
return 0;
}
/**
* tlsv1_record_receive - TLS record layer: Process a received message
* @rl: Pointer to TLS record layer data
* @in_data: Received data
* @in_len: Length of the received data
* @out_data: Buffer for output data (must be at least as long as in_data)
* @out_len: Set to maximum out_data length by caller; used to return the
* length of the used data
* @alert: Buffer for returning an alert value on failure
* Returns: Number of bytes used from in_data on success, 0 if record was not
* complete (more data needed), or -1 on failure
*
* This function decrypts the received message, verifies HMAC and TLS record
* layer header.
*/
int tlsv1_record_receive(struct tlsv1_record_layer *rl,
const u8 *in_data, size_t in_len,
u8 *out_data, size_t *out_len, u8 *alert)
{
size_t i, rlen, hlen;
u8 padlen;
struct crypto_hash *hmac;
u8 len[2], hash[100];
int force_mac_error = 0;
u8 ct;
if (in_len < TLS_RECORD_HEADER_LEN) {
wpa_printf(MSG_DEBUG, "TLSv1: Too short record (in_len=%lu) - "
"need more data",
(unsigned long) in_len);
wpa_hexdump(MSG_MSGDUMP, "TLSv1: Record Layer - Received",
in_data, in_len);
return 0;
}
ct = in_data[0];
rlen = WPA_GET_BE16(in_data + 3);
wpa_printf(MSG_DEBUG, "TLSv1: Received content type %d version %d.%d "
"length %d", ct, in_data[1], in_data[2], (int) rlen);
/*
* TLS v1.0 and v1.1 RFCs were not exactly clear on the use of the
* protocol version in record layer. As such, accept any {03,xx} value
* to remain compatible with existing implementations.
*/
if (in_data[1] != 0x03) {
wpa_printf(MSG_DEBUG, "TLSv1: Unexpected protocol version "
"%u.%u", in_data[1], in_data[2]);
*alert = TLS_ALERT_PROTOCOL_VERSION;
return -1;
}
/* TLSCiphertext must not be more than 2^14+2048 bytes */
if (TLS_RECORD_HEADER_LEN + rlen > 18432) {
wpa_printf(MSG_DEBUG, "TLSv1: Record overflow (len=%lu)",
(unsigned long) (TLS_RECORD_HEADER_LEN + rlen));
*alert = TLS_ALERT_RECORD_OVERFLOW;
return -1;
}
in_data += TLS_RECORD_HEADER_LEN;
in_len -= TLS_RECORD_HEADER_LEN;
if (rlen > in_len) {
wpa_printf(MSG_DEBUG, "TLSv1: Not all record data included "
"(rlen=%lu > in_len=%lu)",
(unsigned long) rlen, (unsigned long) in_len);
return 0;
}
wpa_hexdump(MSG_MSGDUMP, "TLSv1: Record Layer - Received",
in_data, rlen);
if (ct != TLS_CONTENT_TYPE_HANDSHAKE &&
ct != TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC &&
ct != TLS_CONTENT_TYPE_ALERT &&
ct != TLS_CONTENT_TYPE_APPLICATION_DATA) {
wpa_printf(MSG_DEBUG, "TLSv1: Ignore record with unknown "
"content type 0x%x", ct);
*alert = TLS_ALERT_UNEXPECTED_MESSAGE;
return -1;
}
in_len = rlen;
if (*out_len < in_len) {
wpa_printf(MSG_DEBUG, "TLSv1: Not enough output buffer for "
"processing received record");
*alert = TLS_ALERT_INTERNAL_ERROR;
return -1;
}
if (rl->read_cipher_suite != TLS_NULL_WITH_NULL_NULL) {
size_t plen;
if (crypto_cipher_decrypt(rl->read_cbc, in_data,
out_data, in_len) < 0) {
*alert = TLS_ALERT_DECRYPTION_FAILED;
return -1;
}
plen = in_len;
wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: Record Layer - Decrypted "
"data", out_data, plen);
if (rl->iv_size) {
/*
* TLS v1.0 defines different alert values for various
* failures. That may information to aid in attacks, so
* use the same bad_record_mac alert regardless of the
* issues.
*
* In addition, instead of returning immediately on
* error, run through the MAC check to make timing
* attacks more difficult.
*/
if (rl->tls_version >= TLS_VERSION_1_1) {
/* Remove opaque IV[Cipherspec.block_length] */
if (plen < rl->iv_size) {
wpa_printf(MSG_DEBUG, "TLSv1.1: Not "
"enough room for IV");
force_mac_error = 1;
goto check_mac;
}
os_memmove(out_data, out_data + rl->iv_size,
plen - rl->iv_size);
plen -= rl->iv_size;
}
/* Verify and remove padding */
if (plen == 0) {
wpa_printf(MSG_DEBUG, "TLSv1: Too short record"
" (no pad)");
force_mac_error = 1;
goto check_mac;
}
padlen = out_data[plen - 1];
if (padlen >= plen) {
wpa_printf(MSG_DEBUG, "TLSv1: Incorrect pad "
"length (%u, plen=%lu) in "
"received record",
padlen, (unsigned long) plen);
force_mac_error = 1;
goto check_mac;
}
for (i = plen - padlen - 1; i < plen - 1; i++) {
if (out_data[i] != padlen) {
wpa_hexdump(MSG_DEBUG,
"TLSv1: Invalid pad in "
"received record",
out_data + plen - padlen -
1, padlen + 1);
force_mac_error = 1;
goto check_mac;
}
}
plen -= padlen + 1;
wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: Record Layer - "
"Decrypted data with IV and padding "
"removed", out_data, plen);
}
check_mac:
if (plen < rl->hash_size) {
wpa_printf(MSG_DEBUG, "TLSv1: Too short record; no "
"hash value");
*alert = TLS_ALERT_BAD_RECORD_MAC;
return -1;
}
plen -= rl->hash_size;
hmac = crypto_hash_init(rl->hash_alg, rl->read_mac_secret,
rl->hash_size);
if (hmac == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
"to initialize HMAC");
*alert = TLS_ALERT_INTERNAL_ERROR;
return -1;
}
crypto_hash_update(hmac, rl->read_seq_num, TLS_SEQ_NUM_LEN);
/* type + version + length + fragment */
crypto_hash_update(hmac, in_data - TLS_RECORD_HEADER_LEN, 3);
WPA_PUT_BE16(len, plen);
crypto_hash_update(hmac, len, 2);
crypto_hash_update(hmac, out_data, plen);
hlen = sizeof(hash);
if (crypto_hash_finish(hmac, hash, &hlen) < 0) {
wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
"to calculate HMAC");
*alert = TLS_ALERT_INTERNAL_ERROR;
return -1;
}
if (hlen != rl->hash_size ||
os_memcmp_const(hash, out_data + plen, hlen) != 0 ||
force_mac_error) {
wpa_printf(MSG_DEBUG, "TLSv1: Invalid HMAC value in "
"received message (force_mac_error=%d)",
force_mac_error);
*alert = TLS_ALERT_BAD_RECORD_MAC;
return -1;
}
*out_len = plen;
} else {
os_memcpy(out_data, in_data, in_len);
*out_len = in_len;
}
/* TLSCompressed must not be more than 2^14+1024 bytes */
if (TLS_RECORD_HEADER_LEN + *out_len > 17408) {
wpa_printf(MSG_DEBUG, "TLSv1: Record overflow (len=%lu)",
(unsigned long) (TLS_RECORD_HEADER_LEN + *out_len));
*alert = TLS_ALERT_RECORD_OVERFLOW;
return -1;
}
inc_byte_array(rl->read_seq_num, TLS_SEQ_NUM_LEN);
return TLS_RECORD_HEADER_LEN + rlen;
}
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