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hostap/src/tls/tlsv1_common.c
Jouni Malinen 129b9b991a TLS: Share a helper function for verifying Signature 
This same design is used in both the server and the client roles in the
internal TLS implementation. Instead of duplicated implementation, use a
helper function.

Signed-off-by: Jouni Malinen <j@w1.fi>
2014-03-09 17:11:58 +02:00

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/*
* TLSv1 common routines
* Copyright (c) 2006-2014, 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 "x509v3.h"
#include "tlsv1_common.h"
/*
* TODO:
* RFC 2246 Section 9: Mandatory to implement TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
* Add support for commonly used cipher suites; don't bother with exportable
* suites.
*/
static const struct tls_cipher_suite tls_cipher_suites[] = {
{ TLS_NULL_WITH_NULL_NULL, TLS_KEY_X_NULL, TLS_CIPHER_NULL,
TLS_HASH_NULL },
{ TLS_RSA_WITH_RC4_128_MD5, TLS_KEY_X_RSA, TLS_CIPHER_RC4_128,
TLS_HASH_MD5 },
{ TLS_RSA_WITH_RC4_128_SHA, TLS_KEY_X_RSA, TLS_CIPHER_RC4_128,
TLS_HASH_SHA },
{ TLS_RSA_WITH_DES_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_DES_CBC,
TLS_HASH_SHA },
{ TLS_RSA_WITH_3DES_EDE_CBC_SHA, TLS_KEY_X_RSA,
TLS_CIPHER_3DES_EDE_CBC, TLS_HASH_SHA },
{ TLS_DHE_RSA_WITH_DES_CBC_SHA, TLS_KEY_X_DHE_RSA, TLS_CIPHER_DES_CBC,
TLS_HASH_SHA},
{ TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA, TLS_KEY_X_DHE_RSA,
TLS_CIPHER_3DES_EDE_CBC, TLS_HASH_SHA },
{ TLS_DH_anon_WITH_RC4_128_MD5, TLS_KEY_X_DH_anon,
TLS_CIPHER_RC4_128, TLS_HASH_MD5 },
{ TLS_DH_anon_WITH_DES_CBC_SHA, TLS_KEY_X_DH_anon,
TLS_CIPHER_DES_CBC, TLS_HASH_SHA },
{ TLS_DH_anon_WITH_3DES_EDE_CBC_SHA, TLS_KEY_X_DH_anon,
TLS_CIPHER_3DES_EDE_CBC, TLS_HASH_SHA },
{ TLS_RSA_WITH_AES_128_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_AES_128_CBC,
TLS_HASH_SHA },
{ TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_KEY_X_DHE_RSA,
TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA },
{ TLS_DH_anon_WITH_AES_128_CBC_SHA, TLS_KEY_X_DH_anon,
TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA },
{ TLS_RSA_WITH_AES_256_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_AES_256_CBC,
TLS_HASH_SHA },
{ TLS_DHE_RSA_WITH_AES_256_CBC_SHA, TLS_KEY_X_DHE_RSA,
TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA },
{ TLS_DH_anon_WITH_AES_256_CBC_SHA, TLS_KEY_X_DH_anon,
TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA },
{ TLS_RSA_WITH_AES_128_CBC_SHA256, TLS_KEY_X_RSA,
TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA256 },
{ TLS_RSA_WITH_AES_256_CBC_SHA256, TLS_KEY_X_RSA,
TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA256 },
{ TLS_DHE_RSA_WITH_AES_128_CBC_SHA256, TLS_KEY_X_DHE_RSA,
TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA256 },
{ TLS_DHE_RSA_WITH_AES_256_CBC_SHA256, TLS_KEY_X_DHE_RSA,
TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA256 },
{ TLS_DH_anon_WITH_AES_128_CBC_SHA256, TLS_KEY_X_DH_anon,
TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA256 },
{ TLS_DH_anon_WITH_AES_256_CBC_SHA256, TLS_KEY_X_DH_anon,
TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA256 }
};
#define NUM_TLS_CIPHER_SUITES ARRAY_SIZE(tls_cipher_suites)
static const struct tls_cipher_data tls_ciphers[] = {
{ TLS_CIPHER_NULL, TLS_CIPHER_STREAM, 0, 0, 0,
CRYPTO_CIPHER_NULL },
{ TLS_CIPHER_IDEA_CBC, TLS_CIPHER_BLOCK, 16, 16, 8,
CRYPTO_CIPHER_NULL },
{ TLS_CIPHER_RC2_CBC_40, TLS_CIPHER_BLOCK, 5, 16, 0,
CRYPTO_CIPHER_ALG_RC2 },
{ TLS_CIPHER_RC4_40, TLS_CIPHER_STREAM, 5, 16, 0,
CRYPTO_CIPHER_ALG_RC4 },
{ TLS_CIPHER_RC4_128, TLS_CIPHER_STREAM, 16, 16, 0,
CRYPTO_CIPHER_ALG_RC4 },
{ TLS_CIPHER_DES40_CBC, TLS_CIPHER_BLOCK, 5, 8, 8,
CRYPTO_CIPHER_ALG_DES },
{ TLS_CIPHER_DES_CBC, TLS_CIPHER_BLOCK, 8, 8, 8,
CRYPTO_CIPHER_ALG_DES },
{ TLS_CIPHER_3DES_EDE_CBC, TLS_CIPHER_BLOCK, 24, 24, 8,
CRYPTO_CIPHER_ALG_3DES },
{ TLS_CIPHER_AES_128_CBC, TLS_CIPHER_BLOCK, 16, 16, 16,
CRYPTO_CIPHER_ALG_AES },
{ TLS_CIPHER_AES_256_CBC, TLS_CIPHER_BLOCK, 32, 32, 16,
CRYPTO_CIPHER_ALG_AES }
};
#define NUM_TLS_CIPHER_DATA ARRAY_SIZE(tls_ciphers)
/**
* tls_get_cipher_suite - Get TLS cipher suite
* @suite: Cipher suite identifier
* Returns: Pointer to the cipher data or %NULL if not found
*/
const struct tls_cipher_suite * tls_get_cipher_suite(u16 suite)
{
size_t i;
for (i = 0; i < NUM_TLS_CIPHER_SUITES; i++)
if (tls_cipher_suites[i].suite == suite)
return &tls_cipher_suites[i];
return NULL;
}
const struct tls_cipher_data * tls_get_cipher_data(tls_cipher cipher)
{
size_t i;
for (i = 0; i < NUM_TLS_CIPHER_DATA; i++)
if (tls_ciphers[i].cipher == cipher)
return &tls_ciphers[i];
return NULL;
}
int tls_server_key_exchange_allowed(tls_cipher cipher)
{
const struct tls_cipher_suite *suite;
/* RFC 2246, Section 7.4.3 */
suite = tls_get_cipher_suite(cipher);
if (suite == NULL)
return 0;
switch (suite->key_exchange) {
case TLS_KEY_X_DHE_DSS:
case TLS_KEY_X_DHE_DSS_EXPORT:
case TLS_KEY_X_DHE_RSA:
case TLS_KEY_X_DHE_RSA_EXPORT:
case TLS_KEY_X_DH_anon_EXPORT:
case TLS_KEY_X_DH_anon:
return 1;
case TLS_KEY_X_RSA_EXPORT:
return 1 /* FIX: public key len > 512 bits */;
default:
return 0;
}
}
/**
* tls_parse_cert - Parse DER encoded X.509 certificate and get public key
* @buf: ASN.1 DER encoded certificate
* @len: Length of the buffer
* @pk: Buffer for returning the allocated public key
* Returns: 0 on success, -1 on failure
*
* This functions parses an ASN.1 DER encoded X.509 certificate and retrieves
* the public key from it. The caller is responsible for freeing the public key
* by calling crypto_public_key_free().
*/
int tls_parse_cert(const u8 *buf, size_t len, struct crypto_public_key **pk)
{
struct x509_certificate *cert;
wpa_hexdump(MSG_MSGDUMP, "TLSv1: Parse ASN.1 DER certificate",
buf, len);
*pk = crypto_public_key_from_cert(buf, len);
if (*pk)
return 0;
cert = x509_certificate_parse(buf, len);
if (cert == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: Failed to parse X.509 "
"certificate");
return -1;
}
/* TODO
* verify key usage (must allow encryption)
*
* All certificate profiles, key and cryptographic formats are
* defined by the IETF PKIX working group [PKIX]. When a key
* usage extension is present, the digitalSignature bit must be
* set for the key to be eligible for signing, as described
* above, and the keyEncipherment bit must be present to allow
* encryption, as described above. The keyAgreement bit must be
* set on Diffie-Hellman certificates. (PKIX: RFC 3280)
*/
*pk = crypto_public_key_import(cert->public_key, cert->public_key_len);
x509_certificate_free(cert);
if (*pk == NULL) {
wpa_printf(MSG_ERROR, "TLSv1: Failed to import "
"server public key");
return -1;
}
return 0;
}
int tls_verify_hash_init(struct tls_verify_hash *verify)
{
tls_verify_hash_free(verify);
verify->md5_client = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
verify->md5_server = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
verify->md5_cert = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
verify->sha1_client = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
verify->sha1_server = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
verify->sha1_cert = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
if (verify->md5_client == NULL || verify->md5_server == NULL ||
verify->md5_cert == NULL || verify->sha1_client == NULL ||
verify->sha1_server == NULL || verify->sha1_cert == NULL) {
tls_verify_hash_free(verify);
return -1;
}
#ifdef CONFIG_TLSV12
verify->sha256_client = crypto_hash_init(CRYPTO_HASH_ALG_SHA256, NULL,
0);
verify->sha256_server = crypto_hash_init(CRYPTO_HASH_ALG_SHA256, NULL,
0);
verify->sha256_cert = crypto_hash_init(CRYPTO_HASH_ALG_SHA256, NULL,
0);
if (verify->sha256_client == NULL || verify->sha256_server == NULL ||
verify->sha256_cert == NULL) {
tls_verify_hash_free(verify);
return -1;
}
#endif /* CONFIG_TLSV12 */
return 0;
}
void tls_verify_hash_add(struct tls_verify_hash *verify, const u8 *buf,
size_t len)
{
if (verify->md5_client && verify->sha1_client) {
crypto_hash_update(verify->md5_client, buf, len);
crypto_hash_update(verify->sha1_client, buf, len);
}
if (verify->md5_server && verify->sha1_server) {
crypto_hash_update(verify->md5_server, buf, len);
crypto_hash_update(verify->sha1_server, buf, len);
}
if (verify->md5_cert && verify->sha1_cert) {
crypto_hash_update(verify->md5_cert, buf, len);
crypto_hash_update(verify->sha1_cert, buf, len);
}
#ifdef CONFIG_TLSV12
if (verify->sha256_client)
crypto_hash_update(verify->sha256_client, buf, len);
if (verify->sha256_server)
crypto_hash_update(verify->sha256_server, buf, len);
if (verify->sha256_cert)
crypto_hash_update(verify->sha256_cert, buf, len);
#endif /* CONFIG_TLSV12 */
}
void tls_verify_hash_free(struct tls_verify_hash *verify)
{
crypto_hash_finish(verify->md5_client, NULL, NULL);
crypto_hash_finish(verify->md5_server, NULL, NULL);
crypto_hash_finish(verify->md5_cert, NULL, NULL);
crypto_hash_finish(verify->sha1_client, NULL, NULL);
crypto_hash_finish(verify->sha1_server, NULL, NULL);
crypto_hash_finish(verify->sha1_cert, NULL, NULL);
verify->md5_client = NULL;
verify->md5_server = NULL;
verify->md5_cert = NULL;
verify->sha1_client = NULL;
verify->sha1_server = NULL;
verify->sha1_cert = NULL;
#ifdef CONFIG_TLSV12
crypto_hash_finish(verify->sha256_client, NULL, NULL);
crypto_hash_finish(verify->sha256_server, NULL, NULL);
crypto_hash_finish(verify->sha256_cert, NULL, NULL);
verify->sha256_client = NULL;
verify->sha256_server = NULL;
verify->sha256_cert = NULL;
#endif /* CONFIG_TLSV12 */
}
int tls_version_ok(u16 ver)
{
if (ver == TLS_VERSION_1)
return 1;
#ifdef CONFIG_TLSV11
if (ver == TLS_VERSION_1_1)
return 1;
#endif /* CONFIG_TLSV11 */
#ifdef CONFIG_TLSV12
if (ver == TLS_VERSION_1_2)
return 1;
#endif /* CONFIG_TLSV12 */
return 0;
}
const char * tls_version_str(u16 ver)
{
switch (ver) {
case TLS_VERSION_1:
return "1.0";
case TLS_VERSION_1_1:
return "1.1";
case TLS_VERSION_1_2:
return "1.2";
}
return "?";
}
int tls_prf(u16 ver, const u8 *secret, size_t secret_len, const char *label,
const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
{
#ifdef CONFIG_TLSV12
if (ver >= TLS_VERSION_1_2) {
tls_prf_sha256(secret, secret_len, label, seed, seed_len,
out, outlen);
return 0;
}
#endif /* CONFIG_TLSV12 */
return tls_prf_sha1_md5(secret, secret_len, label, seed, seed_len, out,
outlen);
}
#ifdef CONFIG_TLSV12
int tlsv12_key_x_server_params_hash(u16 tls_version,
const u8 *client_random,
const u8 *server_random,
const u8 *server_params,
size_t server_params_len, u8 *hash)
{
size_t hlen;
struct crypto_hash *ctx;
ctx = crypto_hash_init(CRYPTO_HASH_ALG_SHA256, NULL, 0);
if (ctx == NULL)
return -1;
crypto_hash_update(ctx, client_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_params, server_params_len);
hlen = SHA256_MAC_LEN;
if (crypto_hash_finish(ctx, hash, &hlen) < 0)
return -1;
return hlen;
}
#endif /* CONFIG_TLSV12 */
int tls_key_x_server_params_hash(u16 tls_version, const u8 *client_random,
const u8 *server_random,
const u8 *server_params,
size_t server_params_len, u8 *hash)
{
u8 *hpos;
size_t hlen;
enum { SIGN_ALG_RSA, SIGN_ALG_DSA } alg = SIGN_ALG_RSA;
struct crypto_hash *ctx;
hpos = hash;
if (alg == SIGN_ALG_RSA) {
ctx = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
if (ctx == NULL)
return -1;
crypto_hash_update(ctx, client_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_params, server_params_len);
hlen = MD5_MAC_LEN;
if (crypto_hash_finish(ctx, hash, &hlen) < 0)
return -1;
hpos += hlen;
}
ctx = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
if (ctx == NULL)
return -1;
crypto_hash_update(ctx, client_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_random, TLS_RANDOM_LEN);
crypto_hash_update(ctx, server_params, server_params_len);
hlen = hash + sizeof(hash) - hpos;
if (crypto_hash_finish(ctx, hpos, &hlen) < 0)
return -1;
hpos += hlen;
return hpos - hash;
}
int tls_verify_signature(u16 tls_version, struct crypto_public_key *pk,
const u8 *data, size_t data_len,
const u8 *pos, size_t len, u8 *alert)
{
u8 *buf;
const u8 *end = pos + len;
const u8 *decrypted;
u16 slen;
size_t buflen;
if (end - pos < 2) {
*alert = TLS_ALERT_DECODE_ERROR;
return -1;
}
slen = WPA_GET_BE16(pos);
pos += 2;
if (end - pos < slen) {
*alert = TLS_ALERT_DECODE_ERROR;
return -1;
}
if (end - pos > slen) {
wpa_hexdump(MSG_MSGDUMP, "Additional data after Signature",
pos + slen, end - pos - slen);
end = pos + slen;
}
wpa_hexdump(MSG_MSGDUMP, "TLSv1: Signature", pos, end - pos);
if (pk == NULL) {
wpa_printf(MSG_DEBUG, "TLSv1: No public key to verify signature");
*alert = TLS_ALERT_INTERNAL_ERROR;
return -1;
}
buflen = end - pos;
buf = os_malloc(end - pos);
if (buf == NULL) {
*alert = TLS_ALERT_INTERNAL_ERROR;
return -1;
}
if (crypto_public_key_decrypt_pkcs1(pk, pos, end - pos, buf, &buflen) <
0) {
wpa_printf(MSG_DEBUG, "TLSv1: Failed to decrypt signature");
os_free(buf);
*alert = TLS_ALERT_DECRYPT_ERROR;
return -1;
}
decrypted = buf;
wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: Decrypted Signature",
decrypted, buflen);
#ifdef CONFIG_TLSV12
if (tls_version >= TLS_VERSION_1_2) {
/*
* RFC 3447, A.2.4 RSASSA-PKCS1-v1_5
*
* DigestInfo ::= SEQUENCE {
* digestAlgorithm DigestAlgorithm,
* digest OCTET STRING
* }
*
* SHA-256 OID: sha256WithRSAEncryption ::= {pkcs-1 11}
*
* DER encoded DigestInfo for SHA256 per RFC 3447:
* 30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 ||
* H
*/
if (buflen >= 19 + 32 &&
os_memcmp(buf, "\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01"
"\x65\x03\x04\x02\x01\x05\x00\x04\x20", 19) == 0)
{
wpa_printf(MSG_DEBUG, "TLSv1.2: DigestAlgorithn = SHA-256");
decrypted = buf + 19;
buflen -= 19;
} else {
wpa_printf(MSG_DEBUG, "TLSv1.2: Unrecognized DigestInfo");
os_free(buf);
*alert = TLS_ALERT_DECRYPT_ERROR;
return -1;
}
}
#endif /* CONFIG_TLSV12 */
if (buflen != data_len || os_memcmp(decrypted, data, data_len) != 0) {
wpa_printf(MSG_DEBUG, "TLSv1: Invalid Signature in CertificateVerify - did not match calculated hash");
os_free(buf);
*alert = TLS_ALERT_DECRYPT_ERROR;
return -1;
}
os_free(buf);
return 0;
}
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