/*
* Copyright (C) 2000-2016 Free Software Foundation, Inc.
* Copyright (C) 2015-2017 Red Hat, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
/* Functions that relate to the TLS handshake procedure.
*/
#include "gnutls_int.h"
#include "errors.h"
#include "dh.h"
#include "debug.h"
#include "algorithms.h"
#include "cipher.h"
#include "buffers.h"
#include "mbuffers.h"
#include "kx.h"
#include "handshake.h"
#include "num.h"
#include "hash_int.h"
#include "db.h"
#include "extensions.h"
#include "supplemental.h"
#include "auth.h"
#include "sslv2_compat.h"
#include <auth/cert.h>
#include "constate.h"
#include <record.h>
#include <state.h>
#include <ext/srp.h>
#include <ext/session_ticket.h>
#include <ext/status_request.h>
#include <ext/safe_renegotiation.h>
#include <auth/anon.h> /* for gnutls_anon_server_credentials_t */
#include <auth/psk.h> /* for gnutls_psk_server_credentials_t */
#include <random.h>
#include <dtls.h>
#define TRUE 1
#define FALSE 0
static int check_if_null_comp_present(gnutls_session_t session,
uint8_t * data, int datalen);
static int handshake_client(gnutls_session_t session);
static int handshake_server(gnutls_session_t session);
static int
read_server_hello(gnutls_session_t session,
uint8_t * data, int datalen);
static int
recv_handshake_final(gnutls_session_t session, int init);
static int
send_handshake_final(gnutls_session_t session, int init);
/* Empties but does not free the buffer
*/
static inline void
handshake_hash_buffer_empty(gnutls_session_t session)
{
_gnutls_buffers_log("BUF[HSK]: Emptied buffer\n");
session->internals.used_exts_size = 0;
session->internals.handshake_hash_buffer_prev_len = 0;
session->internals.handshake_hash_buffer.length = 0;
return;
}
static int
handshake_hash_add_recvd(gnutls_session_t session,
gnutls_handshake_description_t recv_type,
uint8_t * header, uint16_t header_size,
uint8_t * dataptr, uint32_t datalen);
static int
handshake_hash_add_sent(gnutls_session_t session,
gnutls_handshake_description_t type,
uint8_t * dataptr, uint32_t datalen);
static int
recv_hello_verify_request(gnutls_session_t session,
uint8_t * data, int datalen);
/* Clears the handshake hash buffers and handles.
*/
void _gnutls_handshake_hash_buffers_clear(gnutls_session_t session)
{
session->internals.handshake_hash_buffer_prev_len = 0;
session->internals.handshake_hash_buffer_client_kx_len = 0;
_gnutls_buffer_clear(&session->internals.handshake_hash_buffer);
}
/* this will copy the required values for resuming to
* internals, and to security_parameters.
* this will keep as less data to security_parameters.
*/
static int resume_copy_required_values(gnutls_session_t session)
{
int ret;
/* get the new random values */
memcpy(session->internals.resumed_security_parameters.
server_random, session->security_parameters.server_random,
GNUTLS_RANDOM_SIZE);
memcpy(session->internals.resumed_security_parameters.
client_random, session->security_parameters.client_random,
GNUTLS_RANDOM_SIZE);
/* keep the ciphersuite and compression
* That is because the client must see these in our
* hello message.
*/
ret = _gnutls_set_cipher_suite2(session,
session->internals.
resumed_security_parameters.
cs);
if (ret < 0)
return gnutls_assert_val(ret);
/* or write_compression_algorithm
* they are the same
*/
session->security_parameters.entity =
session->internals.resumed_security_parameters.entity;
if (session->internals.resumed_security_parameters.pversion ==
NULL)
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (_gnutls_set_current_version(session,
session->internals.
resumed_security_parameters.pversion->
id) < 0)
return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
session->security_parameters.cert_type =
session->internals.resumed_security_parameters.cert_type;
memcpy(session->security_parameters.session_id,
session->internals.resumed_security_parameters.session_id,
sizeof(session->security_parameters.session_id));
session->security_parameters.session_id_size =
session->internals.resumed_security_parameters.session_id_size;
return 0;
}
/* this function will produce GNUTLS_RANDOM_SIZE==32 bytes of random data
* and put it to dst.
*/
static int create_tls_random(uint8_t * dst)
{
int ret;
/* Use nonce rng level for the most of the
* buffer except for the first 4 that are the
* system's time.
*/
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
/* When fuzzying avoid timing dependencies */
memset(dst, 1, 4);
#else
uint32_t tim;
tim = gnutls_time(NULL);
/* generate server random value */
_gnutls_write_uint32(tim, dst);
#endif
ret =
gnutls_rnd(GNUTLS_RND_NONCE, &dst[3], GNUTLS_RANDOM_SIZE - 3);
if (ret < 0) {
gnutls_assert();
return ret;
}
return 0;
}
int _gnutls_set_client_random(gnutls_session_t session, uint8_t * rnd)
{
int ret;
if (rnd != NULL)
memcpy(session->security_parameters.client_random, rnd,
GNUTLS_RANDOM_SIZE);
else {
/* no random given, we generate. */
if (session->internals.sc_random_set != 0) {
memcpy(session->security_parameters.client_random,
session->internals.
resumed_security_parameters.client_random,
GNUTLS_RANDOM_SIZE);
} else {
ret =
create_tls_random(session->
security_parameters.
client_random);
if (ret < 0)
return gnutls_assert_val(ret);
}
}
return 0;
}
int _gnutls_set_server_random(gnutls_session_t session, uint8_t * rnd)
{
int ret;
if (rnd != NULL)
memcpy(session->security_parameters.server_random, rnd,
GNUTLS_RANDOM_SIZE);
else {
/* no random given, we generate. */
if (session->internals.sc_random_set != 0) {
memcpy(session->security_parameters.server_random,
session->internals.
resumed_security_parameters.server_random,
GNUTLS_RANDOM_SIZE);
} else {
ret =
create_tls_random(session->
security_parameters.
server_random);
if (ret < 0)
return gnutls_assert_val(ret);
}
}
return 0;
}
#ifdef ENABLE_SSL3
/* Calculate The SSL3 Finished message
*/
#define SSL3_CLIENT_MSG "CLNT"
#define SSL3_SERVER_MSG "SRVR"
#define SSL_MSG_LEN 4
static int
_gnutls_ssl3_finished(gnutls_session_t session, int type, uint8_t * ret,
int sending)
{
digest_hd_st td_md5;
digest_hd_st td_sha;
const char *mesg;
int rc, len;
if (sending)
len = session->internals.handshake_hash_buffer.length;
else
len = session->internals.handshake_hash_buffer_prev_len;
rc = _gnutls_hash_init(&td_sha, hash_to_entry(GNUTLS_DIG_SHA1));
if (rc < 0)
return gnutls_assert_val(rc);
rc = _gnutls_hash_init(&td_md5, hash_to_entry(GNUTLS_DIG_MD5));
if (rc < 0) {
_gnutls_hash_deinit(&td_sha, NULL);
return gnutls_assert_val(rc);
}
_gnutls_hash(&td_sha,
session->internals.handshake_hash_buffer.data, len);
_gnutls_hash(&td_md5,
session->internals.handshake_hash_buffer.data, len);
if (type == GNUTLS_SERVER)
mesg = SSL3_SERVER_MSG;
else
mesg = SSL3_CLIENT_MSG;
_gnutls_hash(&td_md5, mesg, SSL_MSG_LEN);
_gnutls_hash(&td_sha, mesg, SSL_MSG_LEN);
rc = _gnutls_mac_deinit_ssl3_handshake(&td_md5, ret,
session->security_parameters.
master_secret,
GNUTLS_MASTER_SIZE);
if (rc < 0) {
_gnutls_hash_deinit(&td_md5, NULL);
_gnutls_hash_deinit(&td_sha, NULL);
return gnutls_assert_val(rc);
}
rc = _gnutls_mac_deinit_ssl3_handshake(&td_sha, &ret[16],
session->security_parameters.
master_secret,
GNUTLS_MASTER_SIZE);
if (rc < 0) {
_gnutls_hash_deinit(&td_sha, NULL);
return gnutls_assert_val(rc);
}
return 0;
}
#endif
/* Hash the handshake messages as required by TLS 1.0
*/
#define SERVER_MSG "server finished"
#define CLIENT_MSG "client finished"
#define TLS_MSG_LEN 15
static int
_gnutls_finished(gnutls_session_t session, int type, void *ret,
int sending)
{
const int siz = TLS_MSG_LEN;
uint8_t concat[MAX_HASH_SIZE];
size_t hash_len;
const char *mesg;
int rc, len, algorithm;
if (sending)
len = session->internals.handshake_hash_buffer.length;
else
len = session->internals.handshake_hash_buffer_prev_len;
algorithm = session->security_parameters.prf_mac;
rc = _gnutls_hash_fast(algorithm,
session->internals.
handshake_hash_buffer.data, len,
concat);
if (rc < 0)
return gnutls_assert_val(rc);
hash_len = _gnutls_hash_get_algo_len(mac_to_entry(algorithm));
if (type == GNUTLS_SERVER) {
mesg = SERVER_MSG;
} else {
mesg = CLIENT_MSG;
}
return _gnutls_PRF(session,
session->security_parameters.master_secret,
GNUTLS_MASTER_SIZE, mesg, siz, concat, hash_len,
12, ret);
}
/* returns the 0 on success or a negative error code.
*/
int
_gnutls_negotiate_version(gnutls_session_t session,
gnutls_protocol_t adv_version, uint8_t major, uint8_t minor)
{
int ret;
/* if we do not support that version */
if (adv_version == GNUTLS_VERSION_UNKNOWN || _gnutls_version_is_supported(session, adv_version) == 0) {
/* if we get an unknown/unsupported version, then fail if the version we
* got is too low to be supported */
if (!_gnutls_version_is_too_high(session, major, minor))
return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
/* If he requested something we do not support
* then we send him the highest we support.
*/
ret = _gnutls_version_max(session);
if (ret == GNUTLS_VERSION_UNKNOWN) {
/* this check is not really needed.
*/
gnutls_assert();
return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
}
} else {
ret = adv_version;
}
if (_gnutls_set_current_version(session, ret) < 0)
return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
return ret;
}
/* This function returns:
* - zero on success
* - GNUTLS_E_INT_RET_0 if GNUTLS_E_AGAIN || GNUTLS_E_INTERRUPTED were returned by the callback
* - a negative error code on other error
*/
int
_gnutls_user_hello_func(gnutls_session_t session,
gnutls_protocol_t adv_version, uint8_t major, uint8_t minor)
{
int ret, sret = 0;
if (session->internals.user_hello_func != NULL) {
ret = session->internals.user_hello_func(session);
if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED) {
gnutls_assert();
sret = GNUTLS_E_INT_RET_0;
} else if (ret < 0) {
gnutls_assert();
return ret;
}
/* Here we need to renegotiate the version since the callee might
* have disabled some TLS versions.
*/
ret = _gnutls_negotiate_version(session, adv_version, major, minor);
if (ret < 0) {
gnutls_assert();
return ret;
}
}
return sret;
}
/* Read a client hello packet.
* A client hello must be a known version client hello
* or version 2.0 client hello (only for compatibility
* since SSL version 2.0 is not supported).
*/
static int
read_client_hello(gnutls_session_t session, uint8_t * data,
int datalen)
{
uint8_t session_id_len;
int pos = 0, ret;
uint16_t suite_size, comp_size;
int ext_size;
gnutls_protocol_t adv_version;
int neg_version, sret = 0;
int len = datalen;
uint8_t major, minor;
uint8_t *suite_ptr, *comp_ptr, *session_id, *ext_ptr;
DECR_LEN(len, 2);
_gnutls_handshake_log("HSK[%p]: Client's version: %d.%d\n",
session, data[pos], data[pos + 1]);
adv_version = _gnutls_version_get(data[pos], data[pos + 1]);
major = data[pos];
minor = data[pos+1];
set_adv_version(session, major, minor);
neg_version = _gnutls_negotiate_version(session, adv_version, major, minor);
if (neg_version < 0) {
gnutls_assert();
return neg_version;
}
pos += 2;
_gnutls_handshake_log("HSK[%p]: Selected version %s\n",
session, gnutls_protocol_get_name(neg_version));
/* Read client random value.
*/
DECR_LEN(len, GNUTLS_RANDOM_SIZE);
ret = _gnutls_set_client_random(session, &data[pos]);
if (ret < 0)
return gnutls_assert_val(ret);
pos += GNUTLS_RANDOM_SIZE;
ret = _gnutls_set_server_random(session, NULL);
if (ret < 0)
return gnutls_assert_val(ret);
session->security_parameters.timestamp = gnutls_time(NULL);
DECR_LEN(len, 1);
session_id_len = data[pos++];
/* RESUME SESSION
*/
if (session_id_len > GNUTLS_MAX_SESSION_ID_SIZE) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
DECR_LEN(len, session_id_len);
session_id = &data[pos];
pos += session_id_len;
if (IS_DTLS(session)) {
int cookie_size;
DECR_LEN(len, 1);
cookie_size = data[pos++];
DECR_LEN(len, cookie_size);
pos += cookie_size;
}
/* move forward to extensions and store other vals */
DECR_LEN(len, 2);
suite_size = _gnutls_read_uint16(&data[pos]);
pos += 2;
if (suite_size == 0 || (suite_size % 2) != 0)
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
suite_ptr = &data[pos];
DECR_LEN(len, suite_size);
pos += suite_size;
DECR_LEN(len, 1);
comp_size = data[pos++]; /* the number of compression methods */
if (comp_size == 0)
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
comp_ptr = &data[pos];
DECR_LEN(len, comp_size);
pos += comp_size;
ext_ptr = &data[pos];
ext_size = len;
/* Parse only the mandatory to read extensions for resumption.
* We don't want to parse any other extensions since
* we don't want new extension values to override the
* resumed ones.
*/
ret =
_gnutls_parse_extensions(session, GNUTLS_EXT_MANDATORY,
ext_ptr, ext_size);
if (ret < 0) {
gnutls_assert();
return ret;
}
ret =
_gnutls_server_restore_session(session, session_id,
session_id_len);
if (session_id_len > 0)
session->internals.resumption_requested = 1;
if (ret == 0) { /* resumed using default TLS resumption! */
ret = _gnutls_server_select_suite(session, suite_ptr, suite_size, 1);
if (ret < 0)
return gnutls_assert_val(ret);
ret = resume_copy_required_values(session);
if (ret < 0)
return gnutls_assert_val(ret);
session->internals.resumed = RESUME_TRUE;
return _gnutls_user_hello_func(session, adv_version, major, minor);
} else {
_gnutls_generate_session_id(session->security_parameters.
session_id,
&session->security_parameters.
session_id_size);
session->internals.resumed = RESUME_FALSE;
}
/* Parse the extensions (if any)
*
* Unconditionally try to parse extensions; safe renegotiation uses them in
* sslv3 and higher, even though sslv3 doesn't officially support them.
*/
ret = _gnutls_parse_extensions(session, GNUTLS_EXT_APPLICATION,
ext_ptr, ext_size);
/* len is the rest of the parsed length */
if (ret < 0) {
gnutls_assert();
return ret;
}
/* we cache this error code */
sret = _gnutls_user_hello_func(session, adv_version, major, minor);
if (sret < 0 && sret != GNUTLS_E_INT_RET_0) {
gnutls_assert();
return sret;
}
/* Session tickets are parsed in this point */
ret =
_gnutls_parse_extensions(session, GNUTLS_EXT_TLS, ext_ptr, ext_size);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* resumed by session_ticket extension */
if (session->internals.resumed != RESUME_FALSE) {
/* to indicate the client that the current session is resumed */
memcpy(session->internals.resumed_security_parameters.
session_id, session_id, session_id_len);
session->internals.resumed_security_parameters.
session_id_size = session_id_len;
session->internals.resumed_security_parameters.
max_record_recv_size =
session->security_parameters.max_record_recv_size;
session->internals.resumed_security_parameters.
max_record_send_size =
session->security_parameters.max_record_send_size;
ret = _gnutls_server_select_suite(session, suite_ptr, suite_size, 1);
if (ret < 0)
return gnutls_assert_val(ret);
ret = resume_copy_required_values(session);
if (ret < 0)
return gnutls_assert_val(ret);
return 0;
}
/* select an appropriate cipher suite (as well as certificate)
*/
ret = _gnutls_server_select_suite(session, suite_ptr, suite_size, 0);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* select appropriate compression method */
ret =
check_if_null_comp_present(session, comp_ptr,
comp_size);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* call extensions that are intended to be parsed after the ciphersuite/cert
* are known. */
ret =
_gnutls_parse_extensions(session, _GNUTLS_EXT_TLS_POST_CS, ext_ptr, ext_size);
if (ret < 0) {
gnutls_assert();
return ret;
}
return sret;
}
/* This is to be called after sending CHANGE CIPHER SPEC packet
* and initializing encryption. This is the first encrypted message
* we send.
*/
static int _gnutls_send_finished(gnutls_session_t session, int again)
{
mbuffer_st *bufel;
uint8_t *data;
int ret;
size_t vdata_size = 0;
const version_entry_st *vers;
if (again == 0) {
bufel =
_gnutls_handshake_alloc(session,
MAX_VERIFY_DATA_SIZE);
if (bufel == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
data = _mbuffer_get_udata_ptr(bufel);
vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
#ifdef ENABLE_SSL3
if (vers->id == GNUTLS_SSL3) {
ret =
_gnutls_ssl3_finished(session,
session->
security_parameters.
entity, data, 1);
_mbuffer_set_udata_size(bufel, 36);
} else { /* TLS 1.0+ */
#endif
ret = _gnutls_finished(session,
session->
security_parameters.entity,
data, 1);
_mbuffer_set_udata_size(bufel, 12);
#ifdef ENABLE_SSL3
}
#endif
if (ret < 0) {
gnutls_assert();
return ret;
}
vdata_size = _mbuffer_get_udata_size(bufel);
ret =
_gnutls_ext_sr_finished(session, data, vdata_size, 0);
if (ret < 0) {
gnutls_assert();
return ret;
}
if ((session->internals.resumed == RESUME_FALSE
&& session->security_parameters.entity ==
GNUTLS_CLIENT)
|| (session->internals.resumed != RESUME_FALSE
&& session->security_parameters.entity ==
GNUTLS_SERVER)) {
/* if we are a client not resuming - or we are a server resuming */
_gnutls_handshake_log
("HSK[%p]: recording tls-unique CB (send)\n",
session);
memcpy(session->internals.cb_tls_unique, data,
vdata_size);
session->internals.cb_tls_unique_len = vdata_size;
}
ret =
_gnutls_send_handshake(session, bufel,
GNUTLS_HANDSHAKE_FINISHED);
} else {
ret =
_gnutls_send_handshake(session, NULL,
GNUTLS_HANDSHAKE_FINISHED);
}
return ret;
}
/* This is to be called after sending our finished message. If everything
* went fine we have negotiated a secure connection
*/
static int _gnutls_recv_finished(gnutls_session_t session)
{
uint8_t data[MAX_VERIFY_DATA_SIZE], *vrfy;
gnutls_buffer_st buf;
int data_size;
int ret;
int vrfy_size;
const version_entry_st *vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
ret =
_gnutls_recv_handshake(session, GNUTLS_HANDSHAKE_FINISHED,
0, &buf);
if (ret < 0) {
gnutls_assert();
return ret;
}
vrfy = buf.data;
vrfy_size = buf.length;
#ifdef ENABLE_SSL3
if (vers->id == GNUTLS_SSL3)
data_size = 36;
else
#endif
data_size = 12;
if (vrfy_size != data_size) {
gnutls_assert();
ret = GNUTLS_E_ERROR_IN_FINISHED_PACKET;
goto cleanup;
}
#ifdef ENABLE_SSL3
if (vers->id == GNUTLS_SSL3) {
ret =
_gnutls_ssl3_finished(session,
(session->security_parameters.
entity + 1) % 2, data, 0);
} else /* TLS 1.0+ */
#endif
ret =
_gnutls_finished(session,
(session->security_parameters.entity +
1) % 2, data, 0);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
/* When fuzzying allow to proceed without verifying the handshake
* consistency */
# warning This is unsafe for production builds
#else
if (memcmp(vrfy, data, data_size) != 0) {
gnutls_assert();
ret = GNUTLS_E_ERROR_IN_FINISHED_PACKET;
goto cleanup;
}
#endif
ret = _gnutls_ext_sr_finished(session, data, data_size, 1);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if ((session->internals.resumed != RESUME_FALSE
&& session->security_parameters.entity == GNUTLS_CLIENT)
|| (session->internals.resumed == RESUME_FALSE
&& session->security_parameters.entity == GNUTLS_SERVER)) {
/* if we are a client resuming - or we are a server not resuming */
_gnutls_handshake_log
("HSK[%p]: recording tls-unique CB (recv)\n", session);
memcpy(session->internals.cb_tls_unique, data, data_size);
session->internals.cb_tls_unique_len = data_size;
}
session->internals.initial_negotiation_completed = 1;
cleanup:
_gnutls_buffer_clear(&buf);
return ret;
}
/* This selects the best supported ciphersuite from the given ones. Then
* it adds the suite to the session and performs some checks.
*
* When @scsv_only is non-zero only the available SCSVs are parsed
* and acted upon.
*/
int
_gnutls_server_select_suite(gnutls_session_t session, uint8_t * data,
unsigned int datalen, unsigned scsv_only)
{
int ret;
unsigned int i;
ciphersuite_list_st peer_clist;
const gnutls_cipher_suite_entry_st *selected;
int retval;
peer_clist.size = 0;
for (i = 0; i < datalen; i += 2) {
/* we support the TLS renegotiation SCSV, even if we are
* not under SSL 3.0, because openssl sends this SCSV
* on resumption unconditionally. */
/* TLS_RENEGO_PROTECTION_REQUEST = { 0x00, 0xff } */
if (session->internals.priorities->sr != SR_DISABLED &&
data[i] == GNUTLS_RENEGO_PROTECTION_REQUEST_MAJOR &&
data[i + 1] == GNUTLS_RENEGO_PROTECTION_REQUEST_MINOR) {
_gnutls_handshake_log
("HSK[%p]: Received safe renegotiation CS\n",
session);
retval = _gnutls_ext_sr_recv_cs(session);
if (retval < 0) {
gnutls_assert();
return retval;
}
}
/* TLS_FALLBACK_SCSV */
if (data[i] == GNUTLS_FALLBACK_SCSV_MAJOR &&
data[i + 1] == GNUTLS_FALLBACK_SCSV_MINOR) {
unsigned max = _gnutls_version_max(session);
_gnutls_handshake_log
("HSK[%p]: Received fallback CS\n",
session);
if (gnutls_protocol_get_version(session) != max)
return gnutls_assert_val(GNUTLS_E_INAPPROPRIATE_FALLBACK);
} else if (!scsv_only) {
if (peer_clist.size < MAX_CIPHERSUITE_SIZE) {
peer_clist.entry[peer_clist.size] = ciphersuite_to_entry(&data[i]);
if (peer_clist.entry[peer_clist.size] != NULL)
peer_clist.size++;
}
}
}
if (scsv_only)
return 0;
ret = _gnutls_figure_common_ciphersuite(session, &peer_clist, &selected);
if (ret < 0) {
return gnutls_assert_val(ret);
}
_gnutls_handshake_log
("HSK[%p]: Selected cipher suite: %s\n", session, selected->name);
ret = _gnutls_set_cipher_suite2(session, selected);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* check if the credentials (username, public key etc.) are ok
*/
if (_gnutls_get_kx_cred(session, selected->kx_algorithm) == NULL) {
gnutls_assert();
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
/* set the mod_auth_st to the appropriate struct
* according to the KX algorithm. This is needed since all the
* handshake functions are read from there;
*/
session->internals.auth_struct = _gnutls_kx_auth_struct(selected->kx_algorithm);
if (session->internals.auth_struct == NULL) {
_gnutls_handshake_log
("HSK[%p]: Cannot find the appropriate handler for the KX algorithm\n",
session);
gnutls_assert();
return GNUTLS_E_INTERNAL_ERROR;
}
return 0;
}
/* This checks whether the null compression method is present.
*/
static int
check_if_null_comp_present(gnutls_session_t session,
uint8_t * data, int datalen)
{
int j;
for (j = 0; j < datalen; j++) {
if (data[j] == 0)
return 0;
}
/* we were not able to find a the NULL compression
* algorithm
*/
gnutls_assert();
return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM;
}
/* This function sends an empty handshake packet. (like hello request).
* If the previous _gnutls_send_empty_handshake() returned
* GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED, then it must be called again
* (until it returns ok), with NULL parameters.
*/
static int
_gnutls_send_empty_handshake(gnutls_session_t session,
gnutls_handshake_description_t type,
int again)
{
mbuffer_st *bufel;
if (again == 0) {
bufel = _gnutls_handshake_alloc(session, 0);
if (bufel == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
} else
bufel = NULL;
return _gnutls_send_handshake(session, bufel, type);
}
inline
static int call_hook_func(gnutls_session_t session,
gnutls_handshake_description_t type,
int post, unsigned incoming,
const uint8_t *data, unsigned data_size)
{
gnutls_datum_t msg = {(void*)data, data_size};
if (session->internals.h_hook != NULL) {
if ((session->internals.h_type == type
|| session->internals.h_type == GNUTLS_HANDSHAKE_ANY)
&& (session->internals.h_post == post
|| session->internals.h_post == GNUTLS_HOOK_BOTH))
return session->internals.h_hook(session, type,
post, incoming, &msg);
}
return 0;
}
/* This function sends a handshake message of type 'type' containing the
* data specified here. If the previous _gnutls_send_handshake() returned
* GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED, then it must be called again
* (until it returns ok), with NULL parameters.
*/
int
_gnutls_send_handshake(gnutls_session_t session, mbuffer_st * bufel,
gnutls_handshake_description_t type)
{
int ret;
uint8_t *data;
uint32_t datasize, i_datasize;
int pos = 0;
if (bufel == NULL) {
/* we are resuming a previously interrupted
* send.
*/
ret = _gnutls_handshake_io_write_flush(session);
return ret;
}
/* first run */
data = _mbuffer_get_uhead_ptr(bufel);
i_datasize = _mbuffer_get_udata_size(bufel);
datasize = i_datasize + _mbuffer_get_uhead_size(bufel);
data[pos++] = (uint8_t) type;
_gnutls_write_uint24(_mbuffer_get_udata_size(bufel), &data[pos]);
pos += 3;
/* Add DTLS handshake fragment headers. The message will be
* fragmented later by the fragmentation sub-layer. All fields must
* be set properly for HMAC. The HMAC requires we pretend that the
* message was sent in a single fragment. */
if (IS_DTLS(session)) {
_gnutls_write_uint16(session->internals.dtls.
hsk_write_seq++, &data[pos]);
pos += 2;
/* Fragment offset */
_gnutls_write_uint24(0, &data[pos]);
pos += 3;
/* Fragment length */
_gnutls_write_uint24(i_datasize, &data[pos]);
/* pos += 3; */
}
_gnutls_handshake_log("HSK[%p]: %s was queued [%ld bytes]\n",
session, _gnutls_handshake2str(type),
(long) datasize);
/* Here we keep the handshake messages in order to hash them...
*/
if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST)
if ((ret =
handshake_hash_add_sent(session, type, data,
datasize)) < 0) {
gnutls_assert();
_mbuffer_xfree(&bufel);
return ret;
}
ret = call_hook_func(session, type, GNUTLS_HOOK_PRE, 0,
_mbuffer_get_udata_ptr(bufel), _mbuffer_get_udata_size(bufel));
if (ret < 0) {
gnutls_assert();
_mbuffer_xfree(&bufel);
return ret;
}
session->internals.last_handshake_out = type;
ret = _gnutls_handshake_io_cache_int(session, type, bufel);
if (ret < 0) {
_mbuffer_xfree(&bufel);
gnutls_assert();
return ret;
}
ret = call_hook_func(session, type, GNUTLS_HOOK_POST, 0,
_mbuffer_get_udata_ptr(bufel), _mbuffer_get_udata_size(bufel));
if (ret < 0) {
gnutls_assert();
return ret;
}
/* The messages which are followed by another are not sent by default
* but are cached instead */
switch (type) {
case GNUTLS_HANDSHAKE_CERTIFICATE_PKT: /* this one is followed by ServerHelloDone
* or ClientKeyExchange always.
*/
case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS:
case GNUTLS_HANDSHAKE_SERVER_KEY_EXCHANGE: /* as above */
case GNUTLS_HANDSHAKE_SERVER_HELLO: /* as above */
case GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST: /* as above */
case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET: /* followed by ChangeCipherSpec */
/* now for client Certificate, ClientKeyExchange and
* CertificateVerify are always followed by ChangeCipherSpec
*/
case GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY:
case GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE:
ret = 0;
break;
default:
/* send cached messages */
ret = _gnutls_handshake_io_write_flush(session);
break;
}
return ret;
}
#define CHECK_SIZE(ll) \
if ((session->internals.max_handshake_data_buffer_size > 0) && \
(((ll) + session->internals.handshake_hash_buffer.length) > \
session->internals.max_handshake_data_buffer_size)) { \
_gnutls_debug_log("Handshake buffer length is %u (max: %u)\n", (unsigned)((ll) + session->internals.handshake_hash_buffer.length), (unsigned)session->internals.max_handshake_data_buffer_size); \
return gnutls_assert_val(GNUTLS_E_HANDSHAKE_TOO_LARGE); \
}
/* This function add the handshake headers and the
* handshake data to the handshake hash buffers. Needed
* for the finished messages calculations.
*/
static int
handshake_hash_add_recvd(gnutls_session_t session,
gnutls_handshake_description_t recv_type,
uint8_t * header, uint16_t header_size,
uint8_t * dataptr, uint32_t datalen)
{
int ret;
const version_entry_st *vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if ((vers->id != GNUTLS_DTLS0_9 &&
recv_type == GNUTLS_HANDSHAKE_HELLO_VERIFY_REQUEST) ||
recv_type == GNUTLS_HANDSHAKE_HELLO_REQUEST)
return 0;
CHECK_SIZE(header_size + datalen);
session->internals.handshake_hash_buffer_prev_len =
session->internals.handshake_hash_buffer.length;
if (vers->id != GNUTLS_DTLS0_9) {
ret =
_gnutls_buffer_append_data(&session->internals.
handshake_hash_buffer,
header, header_size);
if (ret < 0)
return gnutls_assert_val(ret);
}
if (datalen > 0) {
ret =
_gnutls_buffer_append_data(&session->internals.
handshake_hash_buffer,
dataptr, datalen);
if (ret < 0)
return gnutls_assert_val(ret);
}
/* save the size until client KX. That is because the TLS
* session hash is calculated up to this message.
*/
if (recv_type == GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE)
session->internals.handshake_hash_buffer_client_kx_len =
session->internals.handshake_hash_buffer.length;
return 0;
}
/* This function will store the handshake message we sent.
*/
static int
handshake_hash_add_sent(gnutls_session_t session,
gnutls_handshake_description_t type,
uint8_t * dataptr, uint32_t datalen)
{
int ret;
const version_entry_st *vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
/* We don't check for GNUTLS_HANDSHAKE_HELLO_VERIFY_REQUEST because it
* is not sent via that channel.
*/
if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST) {
CHECK_SIZE(datalen);
if (vers->id == GNUTLS_DTLS0_9) {
/* Old DTLS doesn't include the header in the MAC */
if (datalen < 12) {
gnutls_assert();
return GNUTLS_E_INTERNAL_ERROR;
}
dataptr += 12;
datalen -= 12;
if (datalen == 0)
return 0;
}
ret =
_gnutls_buffer_append_data(&session->internals.
handshake_hash_buffer,
dataptr, datalen);
if (ret < 0)
return gnutls_assert_val(ret);
if (type == GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE)
session->internals.handshake_hash_buffer_client_kx_len =
session->internals.handshake_hash_buffer.length;
return 0;
}
return 0;
}
/* This function will receive handshake messages of the given types,
* and will pass the message to the right place in order to be processed.
* E.g. for the SERVER_HELLO message (if it is expected), it will be
* passed to _gnutls_recv_hello().
*/
int
_gnutls_recv_handshake(gnutls_session_t session,
gnutls_handshake_description_t type,
unsigned int optional, gnutls_buffer_st * buf)
{
int ret, ret2;
handshake_buffer_st hsk;
ret = _gnutls_handshake_io_recv_int(session, type, &hsk, optional);
if (ret < 0) {
if (optional != 0
&& ret == GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET) {
if (buf)
_gnutls_buffer_init(buf);
return 0;
}
return gnutls_assert_val_fatal(ret);
}
session->internals.last_handshake_in = hsk.htype;
ret = call_hook_func(session, hsk.htype, GNUTLS_HOOK_PRE, 1, hsk.data.data, hsk.data.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = handshake_hash_add_recvd(session, hsk.htype,
hsk.header, hsk.header_size,
hsk.data.data,
hsk.data.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
switch (hsk.htype) {
case GNUTLS_HANDSHAKE_CLIENT_HELLO_V2:
case GNUTLS_HANDSHAKE_CLIENT_HELLO:
#ifdef ENABLE_SSL2
if (hsk.htype == GNUTLS_HANDSHAKE_CLIENT_HELLO_V2)
ret =
_gnutls_read_client_hello_v2(session,
hsk.data.data,
hsk.data.length);
else
#endif
ret = read_client_hello(session, hsk.data.data,
hsk.data.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
break;
case GNUTLS_HANDSHAKE_SERVER_HELLO:
ret = read_server_hello(session, hsk.data.data,
hsk.data.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
break;
case GNUTLS_HANDSHAKE_HELLO_VERIFY_REQUEST:
ret =
recv_hello_verify_request(session,
hsk.data.data,
hsk.data.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
} else {
/* Signal our caller we have received a verification cookie
and ClientHello needs to be sent again. */
ret = 1;
}
break;
case GNUTLS_HANDSHAKE_SERVER_HELLO_DONE:
if (hsk.data.length == 0)
ret = 0;
else {
gnutls_assert();
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
goto cleanup;
}
break;
case GNUTLS_HANDSHAKE_CERTIFICATE_PKT:
case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS:
case GNUTLS_HANDSHAKE_FINISHED:
case GNUTLS_HANDSHAKE_SERVER_KEY_EXCHANGE:
case GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE:
case GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST:
case GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY:
case GNUTLS_HANDSHAKE_SUPPLEMENTAL:
case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET:
ret = hsk.data.length;
break;
default:
gnutls_assert();
/* we shouldn't actually arrive here in any case .
* unexpected messages should be catched after _gnutls_handshake_io_recv_int()
*/
ret = GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET;
goto cleanup;
}
ret2 = call_hook_func(session, hsk.htype, GNUTLS_HOOK_POST, 1, hsk.data.data, hsk.data.length);
if (ret2 < 0) {
ret = ret2;
gnutls_assert();
goto cleanup;
}
if (buf) {
*buf = hsk.data;
return ret;
}
cleanup:
_gnutls_handshake_buffer_clear(&hsk);
return ret;
}
/* This function checks if the given cipher suite is supported, and sets it
* to the session;
*/
static int
set_client_ciphersuite(gnutls_session_t session, uint8_t suite[2])
{
unsigned j;
int ret;
const gnutls_cipher_suite_entry_st *selected = NULL;
for (j = 0; j < session->internals.priorities->cs.size; j++) {
if (suite[0] == session->internals.priorities->cs.entry[j]->id[0] &&
suite[1] == session->internals.priorities->cs.entry[j]->id[1]) {
selected = session->internals.priorities->cs.entry[j];
break;
}
}
if (!selected) {
gnutls_assert();
_gnutls_handshake_log
("HSK[%p]: unsupported cipher suite %.2X.%.2X was negotiated\n",
session, (unsigned int) suite[0],
(unsigned int) suite[1]);
return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
}
ret = _gnutls_set_cipher_suite2(session, selected);
if (ret < 0)
return gnutls_assert_val(ret);
_gnutls_handshake_log("HSK[%p]: Selected cipher suite: %s\n",
session,
selected->name);
/* check if the credentials (username, public key etc.) are ok.
* Actually checks if they exist.
*/
if (!session->internals.premaster_set &&
_gnutls_get_kx_cred
(session, selected->kx_algorithm) == NULL) {
gnutls_assert();
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
/* set the mod_auth_st to the appropriate struct
* according to the KX algorithm. This is needed since all the
* handshake functions are read from there;
*/
session->internals.auth_struct =
_gnutls_kx_auth_struct(selected->kx_algorithm);
if (session->internals.auth_struct == NULL) {
_gnutls_handshake_log
("HSK[%p]: Cannot find the appropriate handler for the KX algorithm\n",
session);
gnutls_assert();
return GNUTLS_E_INTERNAL_ERROR;
}
return 0;
}
/* This function returns 0 if we are resuming a session or -1 otherwise.
* This also sets the variables in the session. Used only while reading a server
* hello.
*/
static int
client_check_if_resuming(gnutls_session_t session,
uint8_t * session_id, int session_id_len)
{
char buf[2 * GNUTLS_MAX_SESSION_ID_SIZE + 1];
int ret;
_gnutls_handshake_log("HSK[%p]: SessionID length: %d\n", session,
session_id_len);
_gnutls_handshake_log("HSK[%p]: SessionID: %s\n", session,
_gnutls_bin2hex(session_id, session_id_len,
buf, sizeof(buf), NULL));
if ((session->internals.resumption_requested != 0 ||
session->internals.premaster_set != 0) &&
session_id_len > 0 &&
session->internals.resumed_security_parameters.
session_id_size == session_id_len
&& memcmp(session_id,
session->internals.resumed_security_parameters.
session_id, session_id_len) == 0) {
/* resume session */
memcpy(session->internals.resumed_security_parameters.
server_random,
session->security_parameters.server_random,
GNUTLS_RANDOM_SIZE);
memcpy(session->internals.resumed_security_parameters.
client_random,
session->security_parameters.client_random,
GNUTLS_RANDOM_SIZE);
ret = _gnutls_set_cipher_suite2
(session,
session->internals.resumed_security_parameters.
cs);
if (ret < 0) {
gnutls_assert();
goto no_resume;
}
session->internals.resumed = RESUME_TRUE; /* we are resuming */
return 0;
} else {
no_resume:
/* keep the new session id */
session->internals.resumed = RESUME_FALSE; /* we are not resuming */
session->security_parameters.session_id_size =
session_id_len;
if (session_id_len > 0) {
memcpy(session->security_parameters.session_id, session_id,
session_id_len);
}
return -1;
}
}
/* This function reads and parses the server hello handshake message.
* This function also restores resumed parameters if we are resuming a
* session.
*/
static int
read_server_hello(gnutls_session_t session,
uint8_t * data, int datalen)
{
uint8_t session_id_len = 0;
int pos = 0;
int ret = 0;
gnutls_protocol_t version;
int len = datalen;
if (datalen < 38) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
_gnutls_handshake_log("HSK[%p]: Server's version: %d.%d\n",
session, data[pos], data[pos + 1]);
DECR_LEN(len, 2);
version = _gnutls_version_get(data[pos], data[pos + 1]);
if (_gnutls_version_is_supported(session, version) == 0) {
gnutls_assert();
return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
}
if (_gnutls_set_current_version(session, version) < 0)
return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
pos += 2;
DECR_LEN(len, GNUTLS_RANDOM_SIZE);
ret = _gnutls_set_server_random(session, &data[pos]);
if (ret < 0)
return gnutls_assert_val(ret);
pos += GNUTLS_RANDOM_SIZE;
/* Read session ID
*/
DECR_LEN(len, 1);
session_id_len = data[pos++];
if (len < session_id_len || session_id_len > GNUTLS_MAX_SESSION_ID_SIZE) {
gnutls_assert();
return GNUTLS_E_ILLEGAL_PARAMETER;
}
DECR_LEN(len, session_id_len);
/* check if we are resuming and set the appropriate
* values;
*/
if (client_check_if_resuming
(session, &data[pos], session_id_len) == 0) {
pos += session_id_len + 2 + 1;
DECR_LEN(len, 2 + 1);
ret =
_gnutls_parse_extensions(session, GNUTLS_EXT_MANDATORY,
&data[pos], len);
if (ret < 0) {
gnutls_assert();
return ret;
}
return 0;
}
pos += session_id_len;
/* Check if the given cipher suite is supported and copy
* it to the session.
*/
DECR_LEN(len, 2);
ret = set_client_ciphersuite(session, &data[pos]);
if (ret < 0) {
gnutls_assert();
return ret;
}
pos += 2;
/* move to compression
*/
DECR_LEN(len, 1);
pos++;
/* Parse extensions.
*/
ret =
_gnutls_parse_extensions(session, GNUTLS_EXT_ANY, &data[pos],
len);
if (ret < 0) {
gnutls_assert();
return ret;
}
return ret;
}
/* This function copies the appropriate compression methods, to a locally allocated buffer
* Needed in hello messages. Returns the new data length.
*/
static int
append_null_comp(gnutls_session_t session,
gnutls_buffer_st * cdata)
{
uint8_t compression_methods[2] = {0x01, 0x00};
size_t init_length = cdata->length;
int ret;
ret =
_gnutls_buffer_append_data(cdata, compression_methods, 2);
if (ret < 0)
return gnutls_assert_val(ret);
ret = cdata->length - init_length;
return ret;
}
/* This function sends the client hello handshake message.
*/
static int send_client_hello(gnutls_session_t session, int again)
{
mbuffer_st *bufel = NULL;
int type;
int ret = 0;
const version_entry_st *hver, *min_ver;
uint8_t tver[2];
gnutls_buffer_st extdata;
int rehandshake = 0;
unsigned add_sr_scsv = 0;
uint8_t session_id_len =
session->internals.resumed_security_parameters.session_id_size;
_gnutls_buffer_init(&extdata);
/* note that rehandshake is different than resuming
*/
if (session->security_parameters.session_id_size)
rehandshake = 1;
if (again == 0) {
/* if we are resuming a session then we set the
* version number to the previously established.
*/
if (session->internals.resumption_requested == 0 &&
session->internals.premaster_set == 0) {
if (rehandshake) /* already negotiated version thus version_max == negotiated version */
hver = get_version(session);
else /* new handshake. just get the max */
hver =
version_to_entry(_gnutls_version_max
(session));
} else {
/* we are resuming a session */
hver =
session->internals.resumed_security_parameters.
pversion;
}
if (hver == NULL) {
gnutls_assert();
return GNUTLS_E_NO_PRIORITIES_WERE_SET;
}
if (unlikely(session->internals.default_hello_version[0] != 0)) {
tver[0] = session->internals.default_hello_version[0];
tver[1] = session->internals.default_hello_version[1];
} else {
tver[0] = hver->major;
tver[1] = hver->minor;
}
ret = _gnutls_buffer_append_data(&extdata, tver, 2);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
_gnutls_handshake_log("HSK[%p]: Adv. version: %u.%u\n", session,
(unsigned)tver[0], (unsigned)tver[1]);
min_ver = _gnutls_version_lowest(session);
if (min_ver == NULL) {
gnutls_assert();
ret = GNUTLS_E_NO_PRIORITIES_WERE_SET;
goto cleanup;
}
/* Set the version we advertized as maximum
* (RSA uses it).
*/
set_adv_version(session, hver->major, hver->minor);
if (_gnutls_set_current_version(session, hver->id) < 0)
return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
if (session->internals.priorities->min_record_version != 0) {
/* Advertize the lowest supported (SSL 3.0) record packet
* version in record packets during the handshake.
* That is to avoid confusing implementations
* that do not support TLS 1.2 and don't know
* how 3,3 version of record packets look like.
*/
_gnutls_record_set_default_version(session,
min_ver->major, min_ver->minor);
} else {
_gnutls_record_set_default_version(session,
hver->major, hver->minor);
}
/* In order to know when this session was initiated.
*/
session->security_parameters.timestamp = gnutls_time(NULL);
/* Generate random data
*/
if (!IS_DTLS(session)
|| session->internals.dtls.hsk_hello_verify_requests ==
0) {
ret = _gnutls_set_client_random(session, NULL);
if (ret < 0)
return gnutls_assert_val(ret);
}
ret = _gnutls_buffer_append_data(&extdata,
session->security_parameters.client_random,
GNUTLS_RANDOM_SIZE);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
/* Copy the Session ID
*/
ret = _gnutls_buffer_append_data_prefix(&extdata, 8,
session->internals.resumed_security_parameters.session_id,
session_id_len);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
/* Copy the DTLS cookie
*/
if (IS_DTLS(session)) {
ret = _gnutls_buffer_append_data_prefix(&extdata, 8, session->internals.dtls.cookie,
session->internals.dtls.cookie_len);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
}
/* Copy the ciphersuites.
*/
#ifdef ENABLE_SSL3
/* If using SSLv3 Send TLS_RENEGO_PROTECTION_REQUEST SCSV for MITM
* prevention on initial negotiation (but not renegotiation; that's
* handled with the RI extension below).
*/
if (!session->internals.initial_negotiation_completed &&
session->security_parameters.entity == GNUTLS_CLIENT &&
(hver->id == GNUTLS_SSL3 &&
session->internals.priorities->no_extensions != 0)) {
add_sr_scsv = 1;
}
#endif
ret = _gnutls_get_client_ciphersuites(session, &extdata, min_ver, hver, add_sr_scsv);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
/* Copy the compression methods.
*/
ret = append_null_comp(session, &extdata);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
/* Generate and copy TLS extensions.
*/
if (session->internals.priorities->no_extensions == 0) {
if (_gnutls_version_has_extensions(hver)) {
type = GNUTLS_EXT_ANY;
} else {
type = GNUTLS_EXT_MANDATORY;
}
ret =
_gnutls_gen_extensions(session, &extdata,
type);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
}
bufel =
_gnutls_handshake_alloc(session, extdata.length);
if (bufel == NULL) {
gnutls_assert();
ret = GNUTLS_E_MEMORY_ERROR;
goto cleanup;
}
_mbuffer_set_udata_size(bufel, 0);
ret =
_mbuffer_append_data(bufel, extdata.data,
extdata.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
}
_gnutls_buffer_clear(&extdata);
return
_gnutls_send_handshake(session, bufel,
GNUTLS_HANDSHAKE_CLIENT_HELLO);
cleanup:
_mbuffer_xfree(&bufel);
_gnutls_buffer_clear(&extdata);
return ret;
}
static int send_server_hello(gnutls_session_t session, int again)
{
mbuffer_st *bufel = NULL;
uint8_t *data = NULL;
gnutls_buffer_st extdata;
int pos = 0;
int datalen, ret = 0;
uint8_t session_id_len =
session->security_parameters.session_id_size;
char buf[2 * GNUTLS_MAX_SESSION_ID_SIZE + 1];
const version_entry_st *vers;
_gnutls_buffer_init(&extdata);
if (again == 0) {
datalen = 2 + session_id_len + 1 + GNUTLS_RANDOM_SIZE + 3;
ret =
_gnutls_gen_extensions(session, &extdata,
(session->internals.resumed ==
RESUME_TRUE) ?
GNUTLS_EXT_MANDATORY :
GNUTLS_EXT_ANY);
if (ret < 0) {
gnutls_assert();
goto fail;
}
bufel =
_gnutls_handshake_alloc(session,
datalen + extdata.length);
if (bufel == NULL) {
gnutls_assert();
ret = GNUTLS_E_MEMORY_ERROR;
goto fail;
}
data = _mbuffer_get_udata_ptr(bufel);
vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
data[pos++] = vers->major;
data[pos++] = vers->minor;
memcpy(&data[pos],
session->security_parameters.server_random,
GNUTLS_RANDOM_SIZE);
pos += GNUTLS_RANDOM_SIZE;
data[pos++] = session_id_len;
if (session_id_len > 0) {
memcpy(&data[pos],
session->security_parameters.session_id,
session_id_len);
}
pos += session_id_len;
_gnutls_handshake_log("HSK[%p]: SessionID: %s\n", session,
_gnutls_bin2hex(session->
security_parameters.session_id,
session_id_len, buf,
sizeof(buf), NULL));
memcpy(&data[pos],
session->security_parameters.cs->id, 2);
pos += 2;
data[pos++] = 0x00;
if (extdata.length > 0) {
memcpy(&data[pos], extdata.data, extdata.length);
}
}
ret =
_gnutls_send_handshake(session, bufel,
GNUTLS_HANDSHAKE_SERVER_HELLO);
fail:
_gnutls_buffer_clear(&extdata);
return ret;
}
static int
recv_hello_verify_request(gnutls_session_t session,
uint8_t * data, int datalen)
{
ssize_t len = datalen;
size_t pos = 0;
uint8_t cookie_len;
unsigned int nb_verifs;
if (!IS_DTLS(session)
|| session->security_parameters.entity == GNUTLS_SERVER) {
gnutls_assert();
return GNUTLS_E_INTERNAL_ERROR;
}
nb_verifs = ++session->internals.dtls.hsk_hello_verify_requests;
if (nb_verifs >= MAX_HANDSHAKE_HELLO_VERIFY_REQUESTS) {
/* The server is either buggy, malicious or changing cookie
secrets _way_ too fast. */
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET;
}
/* TODO: determine if we need to do anything with the server version field */
DECR_LEN(len, 2);
pos += 2;
DECR_LEN(len, 1);
cookie_len = data[pos];
pos++;
if (cookie_len > DTLS_MAX_COOKIE_SIZE) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
DECR_LEN(len, cookie_len);
session->internals.dtls.cookie_len = cookie_len;
memcpy(session->internals.dtls.cookie, &data[pos], cookie_len);
if (len != 0) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
/* reset handshake hash buffers */
handshake_hash_buffer_empty(session);
return 0;
}
/* The packets in gnutls_handshake (it's more broad than original TLS handshake)
*
* Client Server
*
* ClientHello -------->
* <-------- ServerHello
*
* Certificate*
* ServerKeyExchange*
* <-------- CertificateRequest*
*
* <-------- ServerHelloDone
* Certificate*
* ClientKeyExchange
* CertificateVerify*
* [ChangeCipherSpec]
* Finished -------->
* NewSessionTicket
* [ChangeCipherSpec]
* <-------- Finished
*
* (*): means optional packet.
*/
/* Handshake when resumming session:
* Client Server
*
* ClientHello -------->
* ServerHello
* [ChangeCipherSpec]
* <-------- Finished
* [ChangeCipherSpec]
* Finished -------->
*
*/
/**
* gnutls_rehandshake:
* @session: is a #gnutls_session_t type.
*
* This function will renegotiate security parameters with the
* client. This should only be called in case of a server.
*
* This message informs the peer that we want to renegotiate
* parameters (perform a handshake).
*
* If this function succeeds (returns 0), you must call the
* gnutls_handshake() function in order to negotiate the new
* parameters.
*
* Since TLS is full duplex some application data might have been
* sent during peer's processing of this message. In that case
* one should call gnutls_record_recv() until GNUTLS_E_REHANDSHAKE
* is returned to clear any pending data. Care must be taken, if
* rehandshake is mandatory, to terminate if it does not start after
* some threshold.
*
* If the client does not wish to renegotiate parameters he
* should reply with an alert message, thus the return code will be
* %GNUTLS_E_WARNING_ALERT_RECEIVED and the alert will be
* %GNUTLS_A_NO_RENEGOTIATION. A client may also choose to ignore
* this message.
*
* Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
**/
int gnutls_rehandshake(gnutls_session_t session)
{
int ret;
/* only server sends that handshake packet */
if (session->security_parameters.entity == GNUTLS_CLIENT)
return GNUTLS_E_INVALID_REQUEST;
_dtls_async_timer_delete(session);
ret =
_gnutls_send_empty_handshake(session,
GNUTLS_HANDSHAKE_HELLO_REQUEST,
AGAIN(STATE50));
STATE = STATE50;
if (ret < 0) {
gnutls_assert();
return ret;
}
STATE = STATE0;
return 0;
}
inline static int
_gnutls_abort_handshake(gnutls_session_t session, int ret)
{
if (((ret == GNUTLS_E_WARNING_ALERT_RECEIVED) &&
(gnutls_alert_get(session) == GNUTLS_A_NO_RENEGOTIATION))
|| ret == GNUTLS_E_GOT_APPLICATION_DATA)
return 0;
/* this doesn't matter */
return GNUTLS_E_INTERNAL_ERROR;
}
static int _gnutls_send_supplemental(gnutls_session_t session, int again)
{
mbuffer_st *bufel;
int ret = 0;
_gnutls_debug_log("EXT[%p]: Sending supplemental data\n", session);
if (again)
ret =
_gnutls_send_handshake(session, NULL,
GNUTLS_HANDSHAKE_SUPPLEMENTAL);
else {
gnutls_buffer_st buf;
_gnutls_buffer_init(&buf);
ret = _gnutls_gen_supplemental(session, &buf);
if (ret < 0) {
gnutls_assert();
return ret;
}
bufel =
_gnutls_handshake_alloc(session,
buf.length);
if (bufel == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
_mbuffer_set_udata(bufel, buf.data, buf.length);
_gnutls_buffer_clear(&buf);
ret = _gnutls_send_handshake(session, bufel,
GNUTLS_HANDSHAKE_SUPPLEMENTAL);
}
return ret;
}
static int _gnutls_recv_supplemental(gnutls_session_t session)
{
gnutls_buffer_st buf;
int ret;
_gnutls_debug_log("EXT[%p]: Expecting supplemental data\n",
session);
ret =
_gnutls_recv_handshake(session, GNUTLS_HANDSHAKE_SUPPLEMENTAL,
1, &buf);
if (ret < 0) {
gnutls_assert();
return ret;
}
ret = _gnutls_parse_supplemental(session, buf.data, buf.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
cleanup:
_gnutls_buffer_clear(&buf);
return ret;
}
/**
* gnutls_handshake:
* @session: is a #gnutls_session_t type.
*
* This function does the handshake of the TLS/SSL protocol, and
* initializes the TLS connection.
*
* This function will fail if any problem is encountered, and will
* return a negative error code. In case of a client, if the client
* has asked to resume a session, but the server couldn't, then a
* full handshake will be performed.
*
* The non-fatal errors expected by this function are:
* %GNUTLS_E_INTERRUPTED, %GNUTLS_E_AGAIN,
* %GNUTLS_E_WARNING_ALERT_RECEIVED, and %GNUTLS_E_GOT_APPLICATION_DATA,
* the latter only in a case of rehandshake.
*
* The former two interrupt the handshake procedure due to the lower
* layer being interrupted, and the latter because of an alert that
* may be sent by a server (it is always a good idea to check any
* received alerts). On these errors call this function again, until it
* returns 0; cf. gnutls_record_get_direction() and
* gnutls_error_is_fatal(). In DTLS sessions the non-fatal error
* %GNUTLS_E_LARGE_PACKET is also possible, and indicates that
* the MTU should be adjusted.
*
* If this function is called by a server after a rehandshake request
* then %GNUTLS_E_GOT_APPLICATION_DATA or
* %GNUTLS_E_WARNING_ALERT_RECEIVED may be returned. Note that these
* are non fatal errors, only in the specific case of a rehandshake.
* Their meaning is that the client rejected the rehandshake request or
* in the case of %GNUTLS_E_GOT_APPLICATION_DATA it could also mean that
* some data were pending. A client may receive that error code if
* it initiates the handshake and the server doesn't agreed.
*
* Returns: %GNUTLS_E_SUCCESS on success, otherwise a negative error code.
**/
int gnutls_handshake(gnutls_session_t session)
{
int ret;
/* sanity check. Verify that there are priorities setup.
*/
if (STATE == STATE0) {
/* first call */
if (session->internals.priorities == NULL ||
session->internals.priorities->cs.size == 0)
return gnutls_assert_val(GNUTLS_E_NO_PRIORITIES_WERE_SET);
ret =
_gnutls_epoch_new(session, 0, NULL);
if (ret < 0)
return gnutls_assert_val(ret);
session->internals.used_exts_size = 0;
session->internals.crt_requested = 0;
session->internals.handshake_in_progress = 1;
session->internals.vc_status = -1;
gettime(&session->internals.handshake_start_time);
if (session->internals.handshake_timeout_ms &&
session->internals.handshake_endtime == 0)
session->internals.handshake_endtime = session->internals.handshake_start_time.tv_sec +
session->internals.handshake_timeout_ms / 1000;
}
if (session->internals.recv_state == RECV_STATE_FALSE_START) {
session_invalidate(session);
return gnutls_assert_val(GNUTLS_E_HANDSHAKE_DURING_FALSE_START);
}
if (session->security_parameters.entity == GNUTLS_CLIENT) {
do {
ret = handshake_client(session);
} while (ret == 1);
} else {
ret = handshake_server(session);
}
if (ret < 0) {
/* In the case of a rehandshake abort
* we should reset the handshake's internal state.
*/
if (_gnutls_abort_handshake(session, ret) == 0)
STATE = STATE0;
return ret;
}
/* clear handshake buffer */
if (session->security_parameters.entity != GNUTLS_CLIENT ||
!(session->internals.flags & GNUTLS_ENABLE_FALSE_START) ||
session->internals.recv_state != RECV_STATE_FALSE_START) {
_gnutls_handshake_hash_buffers_clear(session);
if (IS_DTLS(session) == 0) {
_gnutls_handshake_io_buffer_clear(session);
} else {
_dtls_async_timer_init(session);
}
_gnutls_handshake_internal_state_clear(session);
_gnutls_epoch_bump(session);
}
return 0;
}
/**
* gnutls_handshake_set_timeout:
* @session: is a #gnutls_session_t type.
* @ms: is a timeout value in milliseconds
*
* This function sets the timeout for the TLS handshake process
* to the provided value. Use an @ms value of zero to disable
* timeout, or %GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT for a reasonable
* default value. For the DTLS protocol, the more detailed
* gnutls_dtls_set_timeouts() is provided.
*
* This function requires to set a pull timeout callback. See
* gnutls_transport_set_pull_timeout_function().
*
* Since: 3.1.0
**/
void
gnutls_handshake_set_timeout(gnutls_session_t session, unsigned int ms)
{
if (ms == GNUTLS_INDEFINITE_TIMEOUT) {
session->internals.handshake_timeout_ms = 0;
return;
}
if (ms == GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT)
ms = DEFAULT_HANDSHAKE_TIMEOUT_MS;
if (IS_DTLS(session)) {
gnutls_dtls_set_timeouts(session, DTLS_RETRANS_TIMEOUT, ms);
return;
}
session->internals.handshake_timeout_ms = ms;
}
#define IMED_RET( str, ret, allow_alert) do { \
if (ret < 0) { \
/* EAGAIN and INTERRUPTED are always non-fatal */ \
if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED) \
return ret; \
if (ret == GNUTLS_E_GOT_APPLICATION_DATA && session->internals.initial_negotiation_completed != 0) \
return ret; \
if (session->internals.handshake_suspicious_loops < 16) { \
if (ret == GNUTLS_E_LARGE_PACKET) { \
session->internals.handshake_suspicious_loops++; \
return ret; \
} \
/* a warning alert might interrupt handshake */ \
if (allow_alert != 0 && ret==GNUTLS_E_WARNING_ALERT_RECEIVED) { \
session->internals.handshake_suspicious_loops++; \
return ret; \
} \
} \
gnutls_assert(); \
/* do not allow non-fatal errors at this point */ \
if (gnutls_error_is_fatal(ret) == 0) ret = gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR); \
session_invalidate(session); \
_gnutls_handshake_hash_buffers_clear(session); \
return ret; \
} } while (0)
/* Runs the certificate verification callback.
* side is either GNUTLS_CLIENT or GNUTLS_SERVER.
*/
static int run_verify_callback(gnutls_session_t session, unsigned int side)
{
gnutls_certificate_credentials_t cred;
int ret, type;
cred =
(gnutls_certificate_credentials_t) _gnutls_get_cred(session,
GNUTLS_CRD_CERTIFICATE);
if (side == GNUTLS_CLIENT)
type = gnutls_auth_server_get_type(session);
else
type = gnutls_auth_client_get_type(session);
if (type != GNUTLS_CRD_CERTIFICATE)
return 0;
/* verify whether the certificate of the peer remained the same
* as with any previous handshakes */
if (cred != NULL) {
ret = _gnutls_check_if_cert_hash_is_same(session, cred);
if (ret < 0) {
return gnutls_assert_val(ret);
}
}
if (cred != NULL &&
(cred->verify_callback != NULL || session->internals.verify_callback != NULL) &&
(session->security_parameters.entity == GNUTLS_CLIENT ||
session->internals.send_cert_req != GNUTLS_CERT_IGNORE)) {
if (session->internals.verify_callback)
ret = session->internals.verify_callback(session);
else
ret = cred->verify_callback(session);
if (ret < -1)
return gnutls_assert_val(ret);
else if (ret != 0)
return gnutls_assert_val(GNUTLS_E_CERTIFICATE_ERROR);
}
return 0;
}
static bool can_send_false_start(gnutls_session_t session)
{
const version_entry_st *vers;
vers = get_version(session);
if (unlikely(vers == NULL || !vers->false_start))
return 0;
if (session->internals.selected_cert_list != NULL)
return 0;
if (!_gnutls_kx_allows_false_start(session))
return 0;
return 1;
}
/*
* handshake_client
* This function performs the client side of the handshake of the TLS/SSL protocol.
*/
static int handshake_client(gnutls_session_t session)
{
int ret = 0;
switch (STATE) {
case STATE0:
case STATE1:
ret = send_client_hello(session, AGAIN(STATE1));
STATE = STATE1;
IMED_RET("send hello", ret, 1);
/* fall through */
case STATE2:
if (IS_DTLS(session)) {
ret =
_gnutls_recv_handshake(session,
GNUTLS_HANDSHAKE_HELLO_VERIFY_REQUEST,
1, NULL);
STATE = STATE2;
IMED_RET("recv hello verify", ret, 1);
if (ret == 1) {
STATE = STATE0;
return 1;
}
}
/* fall through */
case STATE3:
/* receive the server hello */
ret =
_gnutls_recv_handshake(session,
GNUTLS_HANDSHAKE_SERVER_HELLO,
0, NULL);
STATE = STATE3;
IMED_RET("recv hello", ret, 1);
/* fall through */
case STATE4:
ret = _gnutls_ext_sr_verify(session);
STATE = STATE4;
IMED_RET("recv hello", ret, 0);
/* fall through */
case STATE5:
if (session->security_parameters.do_recv_supplemental) {
ret = _gnutls_recv_supplemental(session);
STATE = STATE5;
IMED_RET("recv supplemental", ret, 1);
}
/* fall through */
case STATE6:
/* RECV CERTIFICATE */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = _gnutls_recv_server_certificate(session);
STATE = STATE6;
IMED_RET("recv server certificate", ret, 1);
/* fall through */
case STATE7:
#ifdef ENABLE_OCSP
/* RECV CERTIFICATE STATUS */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_recv_server_certificate_status
(session);
STATE = STATE7;
IMED_RET("recv server certificate", ret, 1);
#endif
/* fall through */
case STATE8:
ret = run_verify_callback(session, GNUTLS_CLIENT);
STATE = STATE8;
if (ret < 0)
return gnutls_assert_val(ret);
FALLTHROUGH;
case STATE9:
/* receive the server key exchange */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = _gnutls_recv_server_kx_message(session);
STATE = STATE9;
IMED_RET("recv server kx message", ret, 1);
/* fall through */
case STATE10:
/* receive the server certificate request - if any
*/
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = _gnutls_recv_server_crt_request(session);
STATE = STATE10;
IMED_RET("recv server certificate request message", ret,
1);
/* fall through */
case STATE11:
/* receive the server hello done */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_recv_handshake(session,
GNUTLS_HANDSHAKE_SERVER_HELLO_DONE,
0, NULL);
STATE = STATE11;
IMED_RET("recv server hello done", ret, 1);
/* fall through */
case STATE12:
if (session->security_parameters.do_send_supplemental) {
ret =
_gnutls_send_supplemental(session,
AGAIN(STATE12));
STATE = STATE12;
IMED_RET("send supplemental", ret, 0);
}
/* fall through */
case STATE13:
/* send our certificate - if any and if requested
*/
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_send_client_certificate(session,
AGAIN
(STATE13));
STATE = STATE13;
IMED_RET("send client certificate", ret, 0);
/* fall through */
case STATE14:
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_send_client_kx_message(session,
AGAIN(STATE14));
STATE = STATE14;
IMED_RET("send client kx", ret, 0);
/* fall through */
case STATE15:
/* send client certificate verify */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_send_client_certificate_verify(session,
AGAIN
(STATE15));
STATE = STATE15;
IMED_RET("send client certificate verify", ret, 1);
/* fall through */
case STATE16:
STATE = STATE16;
if (session->internals.resumed == RESUME_FALSE) {
ret = send_handshake_final(session, TRUE);
IMED_RET("send handshake final 2", ret, 1);
#ifdef ENABLE_SESSION_TICKETS
} else {
ret = _gnutls_recv_new_session_ticket(session);
IMED_RET("recv handshake new session ticket", ret,
1);
#endif
}
/* fall through */
case STATE17:
STATE = STATE17;
if (session->internals.resumed == RESUME_FALSE && (session->internals.flags & GNUTLS_ENABLE_FALSE_START) && can_send_false_start(session)) {
session->internals.false_start_used = 1;
session->internals.recv_state = RECV_STATE_FALSE_START;
/* complete this phase of the handshake. We
* should be called again by gnutls_record_recv()
*/
STATE = STATE18;
gnutls_assert();
return 0;
} else {
session->internals.false_start_used = 0;
}
/* fall through */
case STATE18:
STATE = STATE18;
if (session->internals.resumed == RESUME_FALSE) {
#ifdef ENABLE_SESSION_TICKETS
ret = _gnutls_recv_new_session_ticket(session);
IMED_RET("recv handshake new session ticket", ret,
1);
#endif
} else {
ret = recv_handshake_final(session, TRUE);
IMED_RET("recv handshake final", ret, 1);
}
/* fall through */
case STATE19:
STATE = STATE19;
if (session->internals.resumed == RESUME_FALSE) {
ret = recv_handshake_final(session, FALSE);
IMED_RET("recv handshake final 2", ret, 1);
} else {
ret = send_handshake_final(session, FALSE);
IMED_RET("send handshake final", ret, 1);
}
STATE = STATE0;
/* fall through */
default:
break;
}
/* explicitly reset any false start flags */
session->internals.recv_state = RECV_STATE_0;
return 0;
}
/* This function is to be called if the handshake was successfully
* completed. This sends a Change Cipher Spec packet to the peer.
*/
static ssize_t send_change_cipher_spec(gnutls_session_t session, int again)
{
uint8_t *data;
mbuffer_st *bufel;
int ret;
const version_entry_st *vers;
if (again == 0) {
bufel = _gnutls_handshake_alloc(session, 1);
if (bufel == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (vers->id == GNUTLS_DTLS0_9)
_mbuffer_set_uhead_size(bufel, 3);
else
_mbuffer_set_uhead_size(bufel, 1);
_mbuffer_set_udata_size(bufel, 0);
data = _mbuffer_get_uhead_ptr(bufel);
data[0] = 1;
if (vers->id == GNUTLS_DTLS0_9) {
_gnutls_write_uint16(session->internals.dtls.
hsk_write_seq, &data[1]);
session->internals.dtls.hsk_write_seq++;
}
ret =
_gnutls_handshake_io_cache_int(session,
GNUTLS_HANDSHAKE_CHANGE_CIPHER_SPEC,
bufel);
if (ret < 0) {
_mbuffer_xfree(&bufel);
return gnutls_assert_val(ret);
}
_gnutls_handshake_log("REC[%p]: Sent ChangeCipherSpec\n",
session);
}
return 0;
}
/* This function sends the final handshake packets and initializes connection
*/
static int send_handshake_final(gnutls_session_t session, int init)
{
int ret = 0;
/* Send the CHANGE CIPHER SPEC PACKET */
switch (FINAL_STATE) {
case STATE0:
case STATE1:
ret = send_change_cipher_spec(session, FAGAIN(STATE1));
FINAL_STATE = STATE0;
if (ret < 0) {
gnutls_assert();
return ret;
}
/* Initialize the connection session (start encryption) - in case of client
*/
if (init == TRUE) {
ret = _gnutls_connection_state_init(session);
if (ret < 0) {
gnutls_assert();
return ret;
}
}
ret = _gnutls_write_connection_state_init(session);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* fall through */
case STATE2:
/* send the finished message */
ret = _gnutls_send_finished(session, FAGAIN(STATE2));
FINAL_STATE = STATE2;
if (ret < 0) {
gnutls_assert();
return ret;
}
FINAL_STATE = STATE0;
/* fall through */
default:
break;
}
return 0;
}
/* This function receives the final handshake packets
* And executes the appropriate function to initialize the
* read session.
*/
static int recv_handshake_final(gnutls_session_t session, int init)
{
int ret = 0;
uint8_t ccs[3];
unsigned int ccs_len = 1;
unsigned int tleft;
const version_entry_st *vers;
ret = handshake_remaining_time(session);
if (ret < 0)
return gnutls_assert_val(ret);
tleft = ret;
switch (FINAL_STATE) {
case STATE0:
case STATE30:
FINAL_STATE = STATE30;
/* This is the last flight and peer cannot be sure
* we have received it unless we notify him. So we
* wait for a message and retransmit if needed. */
if (IS_DTLS(session) && !_dtls_is_async(session) &&
(gnutls_record_check_pending(session) +
record_check_unprocessed(session)) == 0) {
ret = _dtls_wait_and_retransmit(session);
if (ret < 0)
return gnutls_assert_val(ret);
}
vers = get_version(session);
if (unlikely(vers == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (vers->id == GNUTLS_DTLS0_9)
ccs_len = 3;
ret =
_gnutls_recv_int(session, GNUTLS_CHANGE_CIPHER_SPEC,
ccs, ccs_len, NULL, tleft);
if (ret <= 0) {
gnutls_assert();
return (ret<0)?ret:GNUTLS_E_UNEXPECTED_PACKET;
}
if (vers->id == GNUTLS_DTLS0_9)
session->internals.dtls.hsk_read_seq++;
/* Initialize the connection session (start encryption) - in case of server */
if (init == TRUE) {
ret = _gnutls_connection_state_init(session);
if (ret < 0) {
gnutls_assert();
return ret;
}
}
ret = _gnutls_read_connection_state_init(session);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* fall through */
case STATE31:
FINAL_STATE = STATE31;
if (IS_DTLS(session) && !_dtls_is_async(session) &&
(gnutls_record_check_pending(session) +
record_check_unprocessed(session)) == 0) {
ret = _dtls_wait_and_retransmit(session);
if (ret < 0)
return gnutls_assert_val(ret);
}
ret = _gnutls_recv_finished(session);
if (ret < 0) {
gnutls_assert();
return ret;
}
FINAL_STATE = STATE0;
/* fall through */
default:
break;
}
return 0;
}
/*
* handshake_server
* This function does the server stuff of the handshake protocol.
*/
static int handshake_server(gnutls_session_t session)
{
int ret = 0;
switch (STATE) {
case STATE0:
case STATE1:
ret =
_gnutls_recv_handshake(session,
GNUTLS_HANDSHAKE_CLIENT_HELLO,
0, NULL);
if (ret == GNUTLS_E_INT_RET_0) {
/* this is triggered by post_client_hello, and instructs the
* handshake to proceed but be put on hold */
ret = GNUTLS_E_INTERRUPTED;
STATE = STATE2; /* hello already parsed -> move on */
} else {
STATE = STATE1;
}
IMED_RET("recv hello", ret, 1);
/* fall through */
case STATE2:
ret = _gnutls_ext_sr_verify(session);
STATE = STATE2;
IMED_RET("recv hello", ret, 0);
/* fall through */
case STATE3:
ret = send_server_hello(session, AGAIN(STATE3));
STATE = STATE3;
IMED_RET("send hello", ret, 1);
/* fall through */
case STATE4:
if (session->security_parameters.do_send_supplemental) {
ret =
_gnutls_send_supplemental(session,
AGAIN(STATE4));
STATE = STATE4;
IMED_RET("send supplemental data", ret, 0);
}
/* SEND CERTIFICATE + KEYEXCHANGE + CERTIFICATE_REQUEST */
/* fall through */
case STATE5:
/* NOTE: these should not be send if we are resuming */
if (session->internals.resumed == RESUME_FALSE)
ret =
_gnutls_send_server_certificate(session,
AGAIN(STATE5));
STATE = STATE5;
IMED_RET("send server certificate", ret, 0);
/* fall through */
case STATE6:
#ifdef ENABLE_OCSP
if (session->internals.resumed == RESUME_FALSE)
ret =
_gnutls_send_server_certificate_status(session,
AGAIN
(STATE6));
STATE = STATE6;
IMED_RET("send server certificate status", ret, 0);
#endif
/* fall through */
case STATE7:
/* send server key exchange (A) */
if (session->internals.resumed == RESUME_FALSE)
ret =
_gnutls_send_server_kx_message(session,
AGAIN(STATE7));
STATE = STATE7;
IMED_RET("send server kx", ret, 0);
/* fall through */
case STATE8:
/* Send certificate request - if requested to */
if (session->internals.resumed == RESUME_FALSE)
ret =
_gnutls_send_server_crt_request(session,
AGAIN(STATE8));
STATE = STATE8;
IMED_RET("send server cert request", ret, 0);
/* fall through */
case STATE9:
/* send the server hello done */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_send_empty_handshake(session,
GNUTLS_HANDSHAKE_SERVER_HELLO_DONE,
AGAIN(STATE9));
STATE = STATE9;
IMED_RET("send server hello done", ret, 1);
/* fall through */
case STATE10:
if (session->security_parameters.do_recv_supplemental) {
ret = _gnutls_recv_supplemental(session);
STATE = STATE10;
IMED_RET("recv client supplemental", ret, 1);
}
/* RECV CERTIFICATE + KEYEXCHANGE + CERTIFICATE_VERIFY */
/* fall through */
case STATE11:
/* receive the client certificate message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = _gnutls_recv_client_certificate(session);
STATE = STATE11;
IMED_RET("recv client certificate", ret, 1);
/* fall through */
case STATE12:
ret = run_verify_callback(session, GNUTLS_SERVER);
STATE = STATE12;
if (ret < 0)
return gnutls_assert_val(ret);
/* fall through */
case STATE13:
/* receive the client key exchange message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = _gnutls_recv_client_kx_message(session);
STATE = STATE13;
IMED_RET("recv client kx", ret, 1);
/* fall through */
case STATE14:
/* receive the client certificate verify message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
_gnutls_recv_client_certificate_verify_message
(session);
STATE = STATE14;
IMED_RET("recv client certificate verify", ret, 1);
/* fall through */
case STATE15:
STATE = STATE15;
if (session->internals.resumed == RESUME_FALSE) { /* if we are not resuming */
ret = recv_handshake_final(session, TRUE);
IMED_RET("recv handshake final", ret, 1);
} else {
ret = send_handshake_final(session, TRUE);
IMED_RET("send handshake final 2", ret, 1);
}
/* fall through */
case STATE16:
#ifdef ENABLE_SESSION_TICKETS
ret =
_gnutls_send_new_session_ticket(session,
AGAIN(STATE16));
STATE = STATE16;
IMED_RET("send handshake new session ticket", ret, 0);
#endif
/* fall through */
case STATE17:
STATE = STATE17;
if (session->internals.resumed == RESUME_FALSE) { /* if we are not resuming */
ret = send_handshake_final(session, FALSE);
IMED_RET("send handshake final", ret, 1);
if (session->security_parameters.entity ==
GNUTLS_SERVER
&& session->internals.ticket_sent == 0) {
/* if no ticket, save session data */
_gnutls_server_register_current_session
(session);
}
} else {
ret = recv_handshake_final(session, FALSE);
IMED_RET("recv handshake final 2", ret, 1);
}
STATE = STATE0;
/* fall through */
default:
break;
}
return _gnutls_check_id_for_change(session);
}
int _gnutls_generate_session_id(uint8_t * session_id, uint8_t * len)
{
int ret;
*len = GNUTLS_MAX_SESSION_ID_SIZE;
ret =
gnutls_rnd(GNUTLS_RND_NONCE, session_id,
GNUTLS_MAX_SESSION_ID_SIZE);
if (ret < 0) {
gnutls_assert();
return ret;
}
return 0;
}
int
_gnutls_recv_hello_request(gnutls_session_t session, void *data,
uint32_t data_size)
{
uint8_t type;
if (session->security_parameters.entity == GNUTLS_SERVER) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET;
}
if (data_size < 1) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
type = ((uint8_t *) data)[0];
if (type == GNUTLS_HANDSHAKE_HELLO_REQUEST) {
if (IS_DTLS(session))
session->internals.dtls.hsk_read_seq++;
return GNUTLS_E_REHANDSHAKE;
} else {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET;
}
}
/**
* gnutls_handshake_set_max_packet_length:
* @session: is a #gnutls_session_t type.
* @max: is the maximum number.
*
* This function will set the maximum size of all handshake messages.
* Handshakes over this size are rejected with
* %GNUTLS_E_HANDSHAKE_TOO_LARGE error code. The default value is
* 128kb which is typically large enough. Set this to 0 if you do not
* want to set an upper limit.
*
* The reason for restricting the handshake message sizes are to
* limit Denial of Service attacks.
*
* Note that the maximum handshake size was increased to 128kb
* from 48kb in GnuTLS 3.5.5.
**/
void
gnutls_handshake_set_max_packet_length(gnutls_session_t session,
size_t max)
{
session->internals.max_handshake_data_buffer_size = max;
}
/**
* gnutls_handshake_get_last_in:
* @session: is a #gnutls_session_t type.
*
* This function is only useful to check where the last performed
* handshake failed. If the previous handshake succeed or was not
* performed at all then no meaningful value will be returned.
*
* Check %gnutls_handshake_description_t in gnutls.h for the
* available handshake descriptions.
*
* Returns: the last handshake message type received, a
* %gnutls_handshake_description_t.
**/
gnutls_handshake_description_t
gnutls_handshake_get_last_in(gnutls_session_t session)
{
return session->internals.last_handshake_in;
}
/**
* gnutls_handshake_get_last_out:
* @session: is a #gnutls_session_t type.
*
* This function is only useful to check where the last performed
* handshake failed. If the previous handshake succeed or was not
* performed at all then no meaningful value will be returned.
*
* Check %gnutls_handshake_description_t in gnutls.h for the
* available handshake descriptions.
*
* Returns: the last handshake message type sent, a
* %gnutls_handshake_description_t.
**/
gnutls_handshake_description_t
gnutls_handshake_get_last_out(gnutls_session_t session)
{
return session->internals.last_handshake_out;
}
/* This returns the session hash as in draft-ietf-tls-session-hash-02.
*
* FIXME: It duplicates some of the actions in _gnutls_handshake_sign_crt_vrfy*.
* See whether they can be merged.
*/
int _gnutls_handshake_get_session_hash(gnutls_session_t session, gnutls_datum_t *shash)
{
const version_entry_st *ver = get_version(session);
int ret;
const mac_entry_st *me;
uint8_t concat[2*MAX_HASH_SIZE];
if (unlikely(ver == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (session->internals.handshake_hash_buffer_client_kx_len == 0 ||
(session->internals.handshake_hash_buffer.length <
session->internals.handshake_hash_buffer_client_kx_len)) {
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
}
me = mac_to_entry(session->security_parameters.prf_mac);
if (me == NULL)
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
ret =
_gnutls_hash_fast((gnutls_digest_algorithm_t)me->id,
session->internals.handshake_hash_buffer.
data,
session->internals.handshake_hash_buffer_client_kx_len,
concat);
if (ret < 0)
return gnutls_assert_val(ret);
return _gnutls_set_datum(shash, concat, me->output_size);
}