tlsv1_server.c

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/*
 * TLSv1 server (RFC 2246)
 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto/sha1.h"
#include "crypto/tls.h"
#include "tlsv1_common.h"
#include "tlsv1_record.h"
#include "tlsv1_server.h"
#include "tlsv1_server_i.h"

/* TODO:
 * Support for a message fragmented across several records (RFC 2246, 6.2.1)
 */


void tlsv1_server_alert(struct tlsv1_server *conn, u8 level, u8 description)
{
        conn->alert_level = level;
        conn->alert_description = description;
}


int tlsv1_server_derive_keys(struct tlsv1_server *conn,
                             const u8 *pre_master_secret,
                             size_t pre_master_secret_len)
{
        u8 seed[2 * TLS_RANDOM_LEN];
        u8 key_block[TLS_MAX_KEY_BLOCK_LEN];
        u8 *pos;
        size_t key_block_len;

        if (pre_master_secret) {
                wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: pre_master_secret",
                                pre_master_secret, pre_master_secret_len);
                os_memcpy(seed, conn->client_random, TLS_RANDOM_LEN);
                os_memcpy(seed + TLS_RANDOM_LEN, conn->server_random,
                          TLS_RANDOM_LEN);
                if (tls_prf(pre_master_secret, pre_master_secret_len,
                            "master secret", seed, 2 * TLS_RANDOM_LEN,
                            conn->master_secret, TLS_MASTER_SECRET_LEN)) {
                        wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive "
                                   "master_secret");
                        return -1;
                }
                wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: master_secret",
                                conn->master_secret, TLS_MASTER_SECRET_LEN);
        }

        os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
        os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random, TLS_RANDOM_LEN);
        key_block_len = 2 * (conn->rl.hash_size + conn->rl.key_material_len +
                             conn->rl.iv_size);
        if (tls_prf(conn->master_secret, TLS_MASTER_SECRET_LEN,
                    "key expansion", seed, 2 * TLS_RANDOM_LEN,
                    key_block, key_block_len)) {
                wpa_printf(MSG_DEBUG, "TLSv1: Failed to derive key_block");
                return -1;
        }
        wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: key_block",
                        key_block, key_block_len);

        pos = key_block;

        /* client_write_MAC_secret */
        os_memcpy(conn->rl.read_mac_secret, pos, conn->rl.hash_size);
        pos += conn->rl.hash_size;
        /* server_write_MAC_secret */
        os_memcpy(conn->rl.write_mac_secret, pos, conn->rl.hash_size);
        pos += conn->rl.hash_size;

        /* client_write_key */
        os_memcpy(conn->rl.read_key, pos, conn->rl.key_material_len);
        pos += conn->rl.key_material_len;
        /* server_write_key */
        os_memcpy(conn->rl.write_key, pos, conn->rl.key_material_len);
        pos += conn->rl.key_material_len;

        /* client_write_IV */
        os_memcpy(conn->rl.read_iv, pos, conn->rl.iv_size);
        pos += conn->rl.iv_size;
        /* server_write_IV */
        os_memcpy(conn->rl.write_iv, pos, conn->rl.iv_size);
        pos += conn->rl.iv_size;

        return 0;
}


u8 * tlsv1_server_handshake(struct tlsv1_server *conn,
                            const u8 *in_data, size_t in_len,
                            size_t *out_len)
{
        const u8 *pos, *end;
        u8 *msg = NULL, *in_msg, *in_pos, *in_end, alert, ct;
        size_t in_msg_len;

        if (in_data == NULL || in_len == 0) {
                wpa_printf(MSG_DEBUG, "TLSv1: No input data to server");
                return NULL;
        }

        pos = in_data;
        end = in_data + in_len;
        in_msg = os_malloc(in_len);
        if (in_msg == NULL)
                return NULL;

        /* Each received packet may include multiple records */
        while (pos < end) {
                in_msg_len = in_len;
                if (tlsv1_record_receive(&conn->rl, pos, end - pos,
                                         in_msg, &in_msg_len, &alert)) {
                        wpa_printf(MSG_DEBUG, "TLSv1: Processing received "
                                   "record failed");
                        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL, alert);
                        goto failed;
                }
                ct = pos[0];

                in_pos = in_msg;
                in_end = in_msg + in_msg_len;

                /* Each received record may include multiple messages of the
                 * same ContentType. */
                while (in_pos < in_end) {
                        in_msg_len = in_end - in_pos;
                        if (tlsv1_server_process_handshake(conn, ct, in_pos,
                                                           &in_msg_len) < 0)
                                goto failed;
                        in_pos += in_msg_len;
                }

                pos += TLS_RECORD_HEADER_LEN + WPA_GET_BE16(pos + 3);
        }

        os_free(in_msg);
        in_msg = NULL;

        msg = tlsv1_server_handshake_write(conn, out_len);

failed:
        os_free(in_msg);
        if (conn->alert_level) {
                if (conn->state == FAILED) {
                        /* Avoid alert loops */
                        wpa_printf(MSG_DEBUG, "TLSv1: Drop alert loop");
                        os_free(msg);
                        return NULL;
                }
                conn->state = FAILED;
                os_free(msg);
                msg = tlsv1_server_send_alert(conn, conn->alert_level,
                                              conn->alert_description,
                                              out_len);
        }

        return msg;
}


int tlsv1_server_encrypt(struct tlsv1_server *conn,
                         const u8 *in_data, size_t in_len,
                         u8 *out_data, size_t out_len)
{
        size_t rlen;

        wpa_hexdump_key(MSG_MSGDUMP, "TLSv1: Plaintext AppData",
                        in_data, in_len);

        os_memcpy(out_data + TLS_RECORD_HEADER_LEN, in_data, in_len);

        if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_APPLICATION_DATA,
                              out_data, out_len, in_len, &rlen) < 0) {
                wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
                tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
                                   TLS_ALERT_INTERNAL_ERROR);
                return -1;
        }

        return rlen;
}


int tlsv1_server_decrypt(struct tlsv1_server *conn,
                         const u8 *in_data, size_t in_len,
                         u8 *out_data, size_t out_len)
{
        const u8 *in_end, *pos;
        int res;
        u8 alert, *out_end, *out_pos;
        size_t olen;

        pos = in_data;
        in_end = in_data + in_len;
        out_pos = out_data;
        out_end = out_data + out_len;

        while (pos < in_end) {
                if (pos[0] != TLS_CONTENT_TYPE_APPLICATION_DATA) {
                        wpa_printf(MSG_DEBUG, "TLSv1: Unexpected content type "
                                   "0x%x", pos[0]);
                        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
                                           TLS_ALERT_UNEXPECTED_MESSAGE);
                        return -1;
                }

                olen = out_end - out_pos;
                res = tlsv1_record_receive(&conn->rl, pos, in_end - pos,
                                           out_pos, &olen, &alert);
                if (res < 0) {
                        wpa_printf(MSG_DEBUG, "TLSv1: Record layer processing "
                                   "failed");
                        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL, alert);
                        return -1;
                }
                out_pos += olen;
                if (out_pos > out_end) {
                        wpa_printf(MSG_DEBUG, "TLSv1: Buffer not large enough "
                                   "for processing the received record");
                        tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
                                           TLS_ALERT_INTERNAL_ERROR);
                        return -1;
                }

                pos += TLS_RECORD_HEADER_LEN + WPA_GET_BE16(pos + 3);
        }

        return out_pos - out_data;
}


int tlsv1_server_global_init(void)
{
        return crypto_global_init();
}


void tlsv1_server_global_deinit(void)
{
        crypto_global_deinit();
}


struct tlsv1_server * tlsv1_server_init(struct tlsv1_credentials *cred)
{
        struct tlsv1_server *conn;
        size_t count;
        u16 *suites;

        conn = os_zalloc(sizeof(*conn));
        if (conn == NULL)
                return NULL;

        conn->cred = cred;

        conn->state = CLIENT_HELLO;

        if (tls_verify_hash_init(&conn->verify) < 0) {
                wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize verify "
                           "hash");
                os_free(conn);
                return NULL;
        }

        count = 0;
        suites = conn->cipher_suites;
#ifndef CONFIG_CRYPTO_INTERNAL
        suites[count++] = TLS_RSA_WITH_AES_256_CBC_SHA;
#endif /* CONFIG_CRYPTO_INTERNAL */
        suites[count++] = TLS_RSA_WITH_AES_128_CBC_SHA;
        suites[count++] = TLS_RSA_WITH_3DES_EDE_CBC_SHA;
        suites[count++] = TLS_RSA_WITH_RC4_128_SHA;
        suites[count++] = TLS_RSA_WITH_RC4_128_MD5;
        conn->num_cipher_suites = count;

        return conn;
}


static void tlsv1_server_clear_data(struct tlsv1_server *conn)
{
        tlsv1_record_set_cipher_suite(&conn->rl, TLS_NULL_WITH_NULL_NULL);
        tlsv1_record_change_write_cipher(&conn->rl);
        tlsv1_record_change_read_cipher(&conn->rl);
        tls_verify_hash_free(&conn->verify);

        crypto_public_key_free(conn->client_rsa_key);
        conn->client_rsa_key = NULL;

        os_free(conn->session_ticket);
        conn->session_ticket = NULL;
        conn->session_ticket_len = 0;
        conn->use_session_ticket = 0;

        os_free(conn->dh_secret);
        conn->dh_secret = NULL;
        conn->dh_secret_len = 0;
}


void tlsv1_server_deinit(struct tlsv1_server *conn)
{
        tlsv1_server_clear_data(conn);
        os_free(conn);
}


int tlsv1_server_established(struct tlsv1_server *conn)
{
        return conn->state == ESTABLISHED;
}


int tlsv1_server_prf(struct tlsv1_server *conn, const char *label,
                     int server_random_first, u8 *out, size_t out_len)
{
        u8 seed[2 * TLS_RANDOM_LEN];

        if (conn->state != ESTABLISHED)
                return -1;

        if (server_random_first) {
                os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
                os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random,
                          TLS_RANDOM_LEN);
        } else {
                os_memcpy(seed, conn->client_random, TLS_RANDOM_LEN);
                os_memcpy(seed + TLS_RANDOM_LEN, conn->server_random,
                          TLS_RANDOM_LEN);
        }

        return tls_prf(conn->master_secret, TLS_MASTER_SECRET_LEN,
                       label, seed, 2 * TLS_RANDOM_LEN, out, out_len);
}


int tlsv1_server_get_cipher(struct tlsv1_server *conn, char *buf,
                            size_t buflen)
{
        char *cipher;

        switch (conn->rl.cipher_suite) {
        case TLS_RSA_WITH_RC4_128_MD5:
                cipher = "RC4-MD5";
                break;
        case TLS_RSA_WITH_RC4_128_SHA:
                cipher = "RC4-SHA";
                break;
        case TLS_RSA_WITH_DES_CBC_SHA:
                cipher = "DES-CBC-SHA";
                break;
        case TLS_RSA_WITH_3DES_EDE_CBC_SHA:
                cipher = "DES-CBC3-SHA";
                break;
        case TLS_DH_anon_WITH_AES_128_CBC_SHA:
                cipher = "ADH-AES-128-SHA";
                break;
        case TLS_RSA_WITH_AES_256_CBC_SHA:
                cipher = "AES-256-SHA";
                break;
        case TLS_RSA_WITH_AES_128_CBC_SHA:
                cipher = "AES-128-SHA";
                break;
        default:
                return -1;
        }

        if (os_strlcpy(buf, cipher, buflen) >= buflen)
                return -1;
        return 0;
}


int tlsv1_server_shutdown(struct tlsv1_server *conn)
{
        conn->state = CLIENT_HELLO;

        if (tls_verify_hash_init(&conn->verify) < 0) {
                wpa_printf(MSG_DEBUG, "TLSv1: Failed to re-initialize verify "
                           "hash");
                return -1;
        }

        tlsv1_server_clear_data(conn);

        return 0;
}


int tlsv1_server_resumed(struct tlsv1_server *conn)
{
        return 0;
}


int tlsv1_server_get_keys(struct tlsv1_server *conn, struct tls_keys *keys)
{
        os_memset(keys, 0, sizeof(*keys));
        if (conn->state == CLIENT_HELLO)
                return -1;

        keys->client_random = conn->client_random;
        keys->client_random_len = TLS_RANDOM_LEN;

        if (conn->state != SERVER_HELLO) {
                keys->server_random = conn->server_random;
                keys->server_random_len = TLS_RANDOM_LEN;
                keys->master_key = conn->master_secret;
                keys->master_key_len = TLS_MASTER_SECRET_LEN;
        }

        return 0;
}


int tlsv1_server_get_keyblock_size(struct tlsv1_server *conn)
{
        if (conn->state == CLIENT_HELLO || conn->state == SERVER_HELLO)
                return -1;

        return 2 * (conn->rl.hash_size + conn->rl.key_material_len +
                    conn->rl.iv_size);
}


int tlsv1_server_set_cipher_list(struct tlsv1_server *conn, u8 *ciphers)
{
        size_t count;
        u16 *suites;

        /* TODO: implement proper configuration of cipher suites */
        if (ciphers[0] == TLS_CIPHER_ANON_DH_AES128_SHA) {
                count = 0;
                suites = conn->cipher_suites;
#ifndef CONFIG_CRYPTO_INTERNAL
                suites[count++] = TLS_RSA_WITH_AES_256_CBC_SHA;
#endif /* CONFIG_CRYPTO_INTERNAL */
                suites[count++] = TLS_RSA_WITH_AES_128_CBC_SHA;
                suites[count++] = TLS_RSA_WITH_3DES_EDE_CBC_SHA;
                suites[count++] = TLS_RSA_WITH_RC4_128_SHA;
                suites[count++] = TLS_RSA_WITH_RC4_128_MD5;
#ifndef CONFIG_CRYPTO_INTERNAL
                suites[count++] = TLS_DH_anon_WITH_AES_256_CBC_SHA;
#endif /* CONFIG_CRYPTO_INTERNAL */
                suites[count++] = TLS_DH_anon_WITH_AES_128_CBC_SHA;
                suites[count++] = TLS_DH_anon_WITH_3DES_EDE_CBC_SHA;
                suites[count++] = TLS_DH_anon_WITH_RC4_128_MD5;
                suites[count++] = TLS_DH_anon_WITH_DES_CBC_SHA;
                conn->num_cipher_suites = count;
        }

        return 0;
}


int tlsv1_server_set_verify(struct tlsv1_server *conn, int verify_peer)
{
        conn->verify_peer = verify_peer;
        return 0;
}


void tlsv1_server_set_session_ticket_cb(struct tlsv1_server *conn,
                                        tlsv1_server_session_ticket_cb cb,
                                        void *ctx)
{
        wpa_printf(MSG_DEBUG, "TLSv1: SessionTicket callback set %p (ctx %p)",
                   cb, ctx);
        conn->session_ticket_cb = cb;
        conn->session_ticket_cb_ctx = ctx;
}