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|
/*
* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA
*
*/
/* Functions that relate to the TLS handshake procedure.
*/
#include "MHD_config.h"
#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_dh.h"
#include "debug.h"
#include "gnutls_algorithms.h"
#include "gnutls_compress.h"
#include "gnutls_cipher.h"
#include "gnutls_buffers.h"
#include "gnutls_kx.h"
#include "gnutls_handshake.h"
#include "gnutls_num.h"
#include "gnutls_hash_int.h"
#include "gnutls_extensions.h"
#include "gnutls_supplemental.h"
#include "gnutls_auth_int.h"
#include "auth_cert.h"
#include "gnutls_cert.h"
#include "gnutls_constate.h"
#include "gnutls_record.h"
#include "gnutls_state.h"
#include "gnutls_rsa_export.h" /* for MHD_gnutls_get_rsa_params() */
#include "gc.h"
#ifdef HANDSHAKE_DEBUG
#define ERR(x, y) MHD__gnutls_handshake_log( "HSK[%x]: %s (%d)\n", session, x,y)
#else
#define ERR(x, y)
#endif
#define TRUE 1
#define FALSE 0
/* This should be sufficient by now. It should hold all the extensions
* plus the headers in a hello message.
*/
#define MAX_EXT_DATA_LENGTH 1024
static int MHD_gtls_remove_unwanted_ciphersuites (MHD_gtls_session_t session,
cipher_suite_st **
cipherSuites,
int numCipherSuites,
enum
MHD_GNUTLS_PublicKeyAlgorithm);
static int MHD_gtls_server_select_suite (MHD_gtls_session_t session,
opaque * data, int datalen);
static int MHD_gtls_generate_session_id (opaque * session_id, uint8_t * len);
static int MHD_gtls_handshake_common (MHD_gtls_session_t session);
static int MHD_gtls_handshake_server (MHD_gtls_session_t session);
#if MHD_DEBUG_TLS
static int MHD_gtls_handshake_client (MHD_gtls_session_t session);
#endif
static int MHD__gnutls_server_select_comp_method (MHD_gtls_session_t session,
opaque * data, int datalen);
/* Clears the handshake hash buffers and handles.
*/
static void
MHD__gnutls_handshake_hash_buffers_clear (MHD_gtls_session_t session)
{
MHD_gnutls_hash_deinit (session->internals.handshake_mac_handle_md5, NULL);
MHD_gnutls_hash_deinit (session->internals.handshake_mac_handle_sha, NULL);
session->internals.handshake_mac_handle_md5 = NULL;
session->internals.handshake_mac_handle_sha = NULL;
MHD_gtls_handshake_buffer_clear (session);
}
/* this will copy the required values for resuming to
* internals, and to security_parameters.
* this will keep as less data to security_parameters.
*/
static void
resume_copy_required_values (MHD_gtls_session_t session)
{
/* get the new random values */
memcpy (session->internals.resumed_security_parameters.server_random,
session->security_parameters.server_random, TLS_RANDOM_SIZE);
memcpy (session->internals.resumed_security_parameters.client_random,
session->security_parameters.client_random, TLS_RANDOM_SIZE);
/* keep the ciphersuite and compression
* That is because the client must see these in our
* hello message.
*/
memcpy (session->security_parameters.current_cipher_suite.suite,
session->internals.resumed_security_parameters.current_cipher_suite.
suite, 2);
session->internals.compression_method =
session->internals.resumed_security_parameters.read_compression_algorithm;
/* or write_compression_algorithm
* they are the same
*/
session->security_parameters.entity =
session->internals.resumed_security_parameters.entity;
MHD_gtls_set_current_version (session,
session->
internals.resumed_security_parameters.
version);
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;
}
/**
* gnutls_handshake_set_max_packet_length - This function will set the maximum length of a handshake message
* @session: is a #gnutls_session_t structure.
* @max: is the maximum number.
*
* This function will set the maximum size of a handshake message.
* Handshake messages over this size are rejected.
* The default value is 16kb which is large enough. Set this to 0 if you do not want
* to set an upper limit.
*
**/
void
MHD__gnutls_handshake_set_max_packet_length (MHD_gtls_session_t session,
size_t max)
{
session->internals.max_handshake_data_buffer_size = max;
}
static void
MHD_gtls_set_server_random (MHD_gtls_session_t session, uint8_t * rnd)
{
memcpy (session->security_parameters.server_random, rnd, TLS_RANDOM_SIZE);
}
static void
MHD_gtls_set_client_random (MHD_gtls_session_t session, uint8_t * rnd)
{
memcpy (session->security_parameters.client_random, rnd, TLS_RANDOM_SIZE);
}
/* Calculate The SSL3 Finished message */
#define SSL3_CLIENT_MSG "CLNT"
#define SSL3_SERVER_MSG "SRVR"
#define SSL_MSG_LEN 4
static int
MHD__gnutls_ssl3_finished (MHD_gtls_session_t session, int type, opaque * ret)
{
const int siz = SSL_MSG_LEN;
mac_hd_t td_md5;
mac_hd_t td_sha;
const char *mesg;
td_md5 = MHD_gnutls_hash_copy (session->internals.handshake_mac_handle_md5);
if (td_md5 == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_HASH_FAILED;
}
td_sha = MHD_gnutls_hash_copy (session->internals.handshake_mac_handle_sha);
if (td_sha == NULL)
{
MHD_gnutls_assert ();
MHD_gnutls_hash_deinit (td_md5, NULL);
return GNUTLS_E_HASH_FAILED;
}
if (type == GNUTLS_SERVER)
{
mesg = SSL3_SERVER_MSG;
}
else
{
mesg = SSL3_CLIENT_MSG;
}
MHD_gnutls_hash (td_md5, mesg, siz);
MHD_gnutls_hash (td_sha, mesg, siz);
MHD_gnutls_mac_deinit_ssl3_handshake (td_md5, ret,
session->
security_parameters.master_secret,
TLS_MASTER_SIZE);
MHD_gnutls_mac_deinit_ssl3_handshake (td_sha, &ret[16],
session->
security_parameters.master_secret,
TLS_MASTER_SIZE);
return 0;
}
/* 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
MHD__gnutls_finished (MHD_gtls_session_t session, int type, void *ret)
{
const int siz = TLS_MSG_LEN;
opaque concat[36];
size_t len;
const char *mesg;
mac_hd_t td_md5 = NULL;
mac_hd_t td_sha;
enum MHD_GNUTLS_Protocol ver = MHD__gnutls_protocol_get_version (session);
if (ver < MHD_GNUTLS_PROTOCOL_TLS1_2)
{
td_md5 =
MHD_gnutls_hash_copy (session->internals.handshake_mac_handle_md5);
if (td_md5 == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_HASH_FAILED;
}
}
td_sha = MHD_gnutls_hash_copy (session->internals.handshake_mac_handle_sha);
if (td_sha == NULL)
{
MHD_gnutls_assert ();
if (td_md5 != NULL)
MHD_gnutls_hash_deinit (td_md5, NULL);
return GNUTLS_E_HASH_FAILED;
}
if (ver < MHD_GNUTLS_PROTOCOL_TLS1_2)
{
MHD_gnutls_hash_deinit (td_md5, concat);
MHD_gnutls_hash_deinit (td_sha, &concat[16]);
len = 20 + 16;
}
else
{
MHD_gnutls_hash_deinit (td_sha, concat);
len = 20;
}
if (type == GNUTLS_SERVER)
{
mesg = SERVER_MSG;
}
else
{
mesg = CLIENT_MSG;
}
return MHD_gtls_PRF (session, session->security_parameters.master_secret,
TLS_MASTER_SIZE, mesg, siz, concat, len, 12, ret);
}
/* this function will produce TLS_RANDOM_SIZE==32 bytes of random data
* and put it to dst.
*/
static int
MHD_gtls_tls_create_random (opaque * dst)
{
uint32_t tim;
/* Use weak random numbers for the most of the
* buffer except for the first 4 that are the
* system's time.
*/
tim = time (NULL);
/* generate server random value */
MHD_gtls_write_uint32 (tim, dst);
if (MHD_gc_nonce ((char *) &dst[4], TLS_RANDOM_SIZE - 4) != GC_OK)
{
MHD_gnutls_assert ();
return GNUTLS_E_RANDOM_FAILED;
}
return 0;
}
/* returns the 0 on success or a negative value.
*/
static int
MHD_gtls_negotiate_version (MHD_gtls_session_t session,
enum MHD_GNUTLS_Protocol adv_version)
{
int ret;
/* if we do not support that version */
if (MHD_gtls_version_is_supported (session, adv_version) == 0)
{
/* If he requested something we do not support
* then we send him the highest we support.
*/
ret = MHD_gtls_version_max (session);
if (ret == MHD_GNUTLS_PROTOCOL_VERSION_UNKNOWN)
{
/* this check is not really needed.
*/
MHD_gnutls_assert ();
return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
}
}
else
{
ret = adv_version;
}
MHD_gtls_set_current_version (session, ret);
return ret;
}
static int
MHD_gtls_user_hello_func (MHD_gtls_session_t session,
enum MHD_GNUTLS_Protocol adv_version)
{
int ret;
if (session->internals.user_hello_func != NULL)
{
ret = session->internals.user_hello_func (session);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* Here we need to renegotiate the version since the callee might
* have disabled some TLS versions.
*/
ret = MHD_gtls_negotiate_version (session, adv_version);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
return 0;
}
/* 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
MHD__gnutls_read_client_hello (MHD_gtls_session_t session, opaque * data,
int datalen)
{
uint8_t session_id_len;
int pos = 0, ret = 0;
uint16_t suite_size, comp_size;
enum MHD_GNUTLS_Protocol adv_version;
int neg_version;
int len = datalen;
opaque rnd[TLS_RANDOM_SIZE], *suite_ptr, *comp_ptr;
DECR_LEN (len, 2);
MHD__gnutls_handshake_log ("HSK[%x]: Client's version: %d.%d\n", session,
data[pos], data[pos + 1]);
adv_version = MHD_gtls_version_get (data[pos], data[pos + 1]);
set_adv_version (session, data[pos], data[pos + 1]);
pos += 2;
neg_version = MHD_gtls_negotiate_version (session, adv_version);
if (neg_version < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* Read client random value.
*/
DECR_LEN (len, TLS_RANDOM_SIZE);
MHD_gtls_set_client_random (session, &data[pos]);
pos += TLS_RANDOM_SIZE;
MHD_gtls_tls_create_random (rnd);
MHD_gtls_set_server_random (session, rnd);
session->security_parameters.timestamp = time (NULL);
DECR_LEN (len, 1);
session_id_len = data[pos++];
/* RESUME SESSION */
if (session_id_len > TLS_MAX_SESSION_ID_SIZE)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
DECR_LEN (len, session_id_len);
pos += session_id_len;
/* TODO rm if support for resumed sessions won't be supported */
if (0)
{ /* resumed! */
resume_copy_required_values (session);
session->internals.resumed = RESUME_TRUE;
return MHD_gtls_user_hello_func (session, adv_version);
}
else
{
MHD_gtls_generate_session_id (session->security_parameters.session_id,
&session->
security_parameters.session_id_size);
session->internals.resumed = RESUME_FALSE;
}
/* Remember ciphersuites for later
*/
DECR_LEN (len, 2);
suite_size = MHD_gtls_read_uint16 (&data[pos]);
pos += 2;
DECR_LEN (len, suite_size);
suite_ptr = &data[pos];
pos += suite_size;
/* Point to the compression methods
*/
DECR_LEN (len, 1);
comp_size = data[pos++]; /* z is the number of compression methods */
DECR_LEN (len, comp_size);
comp_ptr = &data[pos];
pos += comp_size;
/* Parse the extensions (if any)
*/
if (neg_version >= MHD_GNUTLS_PROTOCOL_TLS1_0)
{
ret = MHD_gtls_parse_extensions (session, EXTENSION_APPLICATION, &data[pos], len); /* len is the rest of the parsed length */
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
ret = MHD_gtls_user_hello_func (session, adv_version);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
if (neg_version >= MHD_GNUTLS_PROTOCOL_TLS1_0)
{
ret = MHD_gtls_parse_extensions (session, EXTENSION_TLS, &data[pos], len); /* len is the rest of the parsed length */
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
/* select an appropriate cipher suite
*/
ret = MHD_gtls_server_select_suite (session, suite_ptr, suite_size);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* select appropriate compression method */
ret = MHD__gnutls_server_select_comp_method (session, comp_ptr, comp_size);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
return 0;
}
/* here we hash all pending data.
*/
static int
MHD__gnutls_handshake_hash_pending (MHD_gtls_session_t session)
{
size_t siz;
int ret;
opaque *data;
if (session->internals.handshake_mac_handle_sha == NULL ||
session->internals.handshake_mac_handle_md5 == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
/* We check if there are pending data to hash.
*/
if ((ret = MHD_gtls_handshake_buffer_get_ptr (session, &data, &siz)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
if (siz > 0)
{
MHD_gnutls_hash (session->internals.handshake_mac_handle_sha, data,
siz);
MHD_gnutls_hash (session->internals.handshake_mac_handle_md5, data,
siz);
}
MHD_gtls_handshake_buffer_empty (session);
return 0;
}
/* This is to be called after sending CHANGE CIPHER SPEC packet
* and initializing encryption. This is the first encrypted message
* we send.
*/
static int
MHD__gnutls_send_finished (MHD_gtls_session_t session, int again)
{
uint8_t data[36];
int ret;
int data_size = 0;
if (again == 0)
{
/* This is needed in order to hash all the required
* messages.
*/
if ((ret = MHD__gnutls_handshake_hash_pending (session)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
if (MHD__gnutls_protocol_get_version (session) ==
MHD_GNUTLS_PROTOCOL_SSL3)
{
ret =
MHD__gnutls_ssl3_finished (session,
session->security_parameters.entity,
data);
data_size = 36;
}
else
{ /* TLS 1.0 */
ret =
MHD__gnutls_finished (session,
session->security_parameters.entity, data);
data_size = 12;
}
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
ret =
MHD_gtls_send_handshake (session, data, data_size,
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
MHD__gnutls_recv_finished (MHD_gtls_session_t session)
{
uint8_t data[36], *vrfy;
int data_size;
int ret;
int vrfysize;
ret =
MHD_gtls_recv_handshake (session, &vrfy, &vrfysize,
GNUTLS_HANDSHAKE_FINISHED, MANDATORY_PACKET);
if (ret < 0)
{
ERR ("recv finished int", ret);
MHD_gnutls_assert ();
return ret;
}
if (MHD__gnutls_protocol_get_version (session) == MHD_GNUTLS_PROTOCOL_SSL3)
{
data_size = 36;
}
else
{
data_size = 12;
}
if (vrfysize != data_size)
{
MHD_gnutls_assert ();
MHD_gnutls_free (vrfy);
return GNUTLS_E_ERROR_IN_FINISHED_PACKET;
}
if (MHD__gnutls_protocol_get_version (session) == MHD_GNUTLS_PROTOCOL_SSL3)
{
ret =
MHD__gnutls_ssl3_finished (session,
(session->security_parameters.entity +
1) % 2, data);
}
else
{ /* TLS 1.0 */
ret =
MHD__gnutls_finished (session,
(session->security_parameters.entity +
1) % 2, data);
}
if (ret < 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (vrfy);
return ret;
}
if (memcmp (vrfy, data, data_size) != 0)
{
MHD_gnutls_assert ();
ret = GNUTLS_E_ERROR_IN_FINISHED_PACKET;
}
MHD_gnutls_free (vrfy);
return ret;
}
/* returns PK_RSA if the given cipher suite list only supports,
* RSA algorithms, PK_DSA if DSS, and PK_ANY for both or PK_NONE for none.
*/
static int
MHD__gnutls_server_find_pk_algos_in_ciphersuites (const opaque *
data, int datalen)
{
int j;
enum MHD_GNUTLS_PublicKeyAlgorithm algo = GNUTLS_PK_NONE, prev_algo = 0;
enum MHD_GNUTLS_KeyExchangeAlgorithm kx;
cipher_suite_st cs;
if (datalen % 2 != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
for (j = 0; j < datalen; j += 2)
{
memcpy (&cs.suite, &data[j], 2);
kx = MHD_gtls_cipher_suite_get_kx_algo (&cs);
if (MHD_gtls_map_kx_get_cred (kx, 1) == MHD_GNUTLS_CRD_CERTIFICATE)
{
algo = MHD_gtls_map_pk_get_pk (kx);
if (algo != prev_algo && prev_algo != 0)
return GNUTLS_PK_ANY;
prev_algo = algo;
}
}
return algo;
}
/* This selects the best supported ciphersuite from the given ones. Then
* it adds the suite to the session and performs some checks.
*/
static int
MHD_gtls_server_select_suite (MHD_gtls_session_t session, opaque * data,
int datalen)
{
int x, i, j;
cipher_suite_st *ciphers, cs;
int retval, err;
enum MHD_GNUTLS_PublicKeyAlgorithm pk_algo; /* will hold the pk algorithms
* supported by the peer.
*/
pk_algo = MHD__gnutls_server_find_pk_algos_in_ciphersuites (data, datalen);
x = MHD_gtls_supported_ciphersuites (session, &ciphers);
if (x < 0)
{ /* the case x==0 is handled within the function. */
MHD_gnutls_assert ();
return x;
}
/* Here we remove any ciphersuite that does not conform
* the certificate requested, or to the
* authentication requested (e.g. SRP).
*/
x = MHD_gtls_remove_unwanted_ciphersuites (session, &ciphers, x, pk_algo);
if (x <= 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (ciphers);
if (x < 0)
return x;
else
return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
}
/* Data length should be zero mod 2 since
* every ciphersuite is 2 bytes. (this check is needed
* see below).
*/
if (datalen % 2 != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
#ifdef HANDSHAKE_DEBUG
MHD__gnutls_handshake_log ("HSK[%x]: Requested cipher suites: \n", session);
for (j = 0; j < datalen; j += 2)
{
memcpy (&cs.suite, &data[j], 2);
MHD__gnutls_handshake_log ("\t%s\n",
MHD_gtls_cipher_suite_get_name (&cs));
}
MHD__gnutls_handshake_log ("HSK[%x]: Supported cipher suites: \n", session);
for (j = 0; j < x; j++)
MHD__gnutls_handshake_log ("\t%s\n",
MHD_gtls_cipher_suite_get_name (&ciphers[j]));
#endif
memset (session->security_parameters.current_cipher_suite.suite, '\0', 2);
retval = GNUTLS_E_UNKNOWN_CIPHER_SUITE;
for (j = 0; j < datalen; j += 2)
{
for (i = 0; i < x; i++)
{
if (memcmp (ciphers[i].suite, &data[j], 2) == 0)
{
memcpy (&cs.suite, &data[j], 2);
MHD__gnutls_handshake_log
("HSK[%x]: Selected cipher suite: %s\n", session,
MHD_gtls_cipher_suite_get_name (&cs));
memcpy (session->security_parameters.current_cipher_suite.suite,
ciphers[i].suite, 2);
retval = 0;
goto finish;
}
}
}
finish:
MHD_gnutls_free (ciphers);
if (retval != 0)
{
MHD_gnutls_assert ();
return retval;
}
/* check if the credentials (username, public key etc.) are ok
*/
if (MHD_gtls_get_kx_cred
(session,
MHD_gtls_cipher_suite_get_kx_algo (&session->
security_parameters.current_cipher_suite),
&err) == NULL && err != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
/* set the MHD_gtls_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 =
MHD_gtls_kx_auth_struct (MHD_gtls_cipher_suite_get_kx_algo
(&session->
security_parameters.current_cipher_suite));
if (session->internals.auth_struct == NULL)
{
MHD__gnutls_handshake_log
("HSK[%x]: Cannot find the appropriate handler for the KX algorithm\n",
session);
MHD_gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
return 0;
}
/* This selects the best supported compression method from the ones provided
*/
static int
MHD__gnutls_server_select_comp_method (MHD_gtls_session_t session,
opaque * data, int datalen)
{
int x, i, j;
uint8_t *comps;
x = MHD_gtls_supported_compression_methods (session, &comps);
if (x < 0)
{
MHD_gnutls_assert ();
return x;
}
memset (&session->internals.compression_method, 0,
sizeof (enum MHD_GNUTLS_CompressionMethod));
for (j = 0; j < datalen; j++)
{
for (i = 0; i < x; i++)
{
if (comps[i] == data[j])
{
enum MHD_GNUTLS_CompressionMethod method =
MHD_gtls_compression_get_id_from_int (comps[i]);
session->internals.compression_method = method;
MHD_gnutls_free (comps);
MHD__gnutls_handshake_log
("HSK[%x]: Selected Compression Method: %s\n", session,
MHD_gtls_compression_get_name (session->
internals.compression_method));
return 0;
}
}
}
/* we were not able to find a compatible compression
* algorithm
*/
MHD_gnutls_free (comps);
MHD_gnutls_assert ();
return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM;
}
/* This function sends an empty handshake packet. (like hello request).
* If the previous MHD__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
MHD__gnutls_send_empty_handshake (MHD_gtls_session_t session,
MHD_gnutls_handshake_description_t type,
int again)
{
opaque data = 0;
opaque *ptr;
if (again == 0)
ptr = &data;
else
ptr = NULL;
return MHD_gtls_send_handshake (session, ptr, 0, type);
}
/* This function will hash the handshake message we sent. */
static int
MHD__gnutls_handshake_hash_add_sent (MHD_gtls_session_t session,
MHD_gnutls_handshake_description_t type,
opaque * dataptr, uint32_t datalen)
{
int ret;
if ((ret = MHD__gnutls_handshake_hash_pending (session)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST)
{
MHD_gnutls_hash (session->internals.handshake_mac_handle_sha, dataptr,
datalen);
MHD_gnutls_hash (session->internals.handshake_mac_handle_md5, dataptr,
datalen);
}
return 0;
}
/* This function sends a handshake message of type 'type' containing the
* data specified here. If the previous MHD_gtls_send_handshake() returned
* GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED, then it must be called again
* (until it returns ok), with NULL parameters.
*/
int
MHD_gtls_send_handshake (MHD_gtls_session_t session, void *i_data,
uint32_t i_datasize,
MHD_gnutls_handshake_description_t type)
{
int ret;
uint8_t *data;
uint32_t datasize;
int pos = 0;
if (i_data == NULL && i_datasize == 0)
{
/* we are resuming a previously interrupted
* send.
*/
ret = MHD_gtls_handshake_io_write_flush (session);
return ret;
}
if (i_data == NULL && i_datasize > 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_INVALID_REQUEST;
}
/* first run */
datasize = i_datasize + HANDSHAKE_HEADER_SIZE;
data = MHD_gnutls_alloca (datasize);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
data[pos++] = (uint8_t) type;
MHD_gtls_write_uint24 (i_datasize, &data[pos]);
pos += 3;
if (i_datasize > 0)
memcpy (&data[pos], i_data, i_datasize);
/* Here we keep the handshake messages in order to hash them...
*/
if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST)
if ((ret =
MHD__gnutls_handshake_hash_add_sent (session, type, data,
datasize)) < 0)
{
MHD_gnutls_assert ();
MHD_gnutls_afree (data);
return ret;
}
session->internals.last_handshake_out = type;
ret =
MHD_gtls_handshake_io_send_int (session, GNUTLS_HANDSHAKE, type,
data, datasize);
MHD__gnutls_handshake_log ("HSK[%x]: %s was sent [%ld bytes]\n",
session, MHD__gnutls_handshake2str (type),
(long) datasize);
MHD_gnutls_afree (data);
return ret;
}
/* This function will read the handshake header and return it to the caller. If the
* received handshake packet is not the one expected then it buffers the header, and
* returns UNEXPECTED_HANDSHAKE_PACKET.
*
* FIXME: This function is complex.
*/
#define SSL2_HEADERS 1
static int
MHD__gnutls_recv_handshake_header (MHD_gtls_session_t session,
MHD_gnutls_handshake_description_t type,
MHD_gnutls_handshake_description_t *
recv_type)
{
int ret;
uint32_t length32 = 0;
uint8_t *dataptr = NULL; /* for realloc */
size_t handshake_header_size = HANDSHAKE_HEADER_SIZE;
/* if we have data into the buffer then return them, do not read the next packet.
* In order to return we need a full TLS handshake header, or in case of a version 2
* packet, then we return the first byte.
*/
if (session->internals.handshake_header_buffer.header_size ==
handshake_header_size || (session->internals.v2_hello != 0
&& type == GNUTLS_HANDSHAKE_CLIENT_HELLO
&& session->internals.handshake_header_buffer.
packet_length > 0))
{
*recv_type = session->internals.handshake_header_buffer.recv_type;
return session->internals.handshake_header_buffer.packet_length;
}
/* Note: SSL2_HEADERS == 1 */
dataptr = session->internals.handshake_header_buffer.header;
/* If we haven't already read the handshake headers.
*/
if (session->internals.handshake_header_buffer.header_size < SSL2_HEADERS)
{
ret =
MHD_gtls_handshake_io_recv_int (session, GNUTLS_HANDSHAKE,
type, dataptr, SSL2_HEADERS);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* The case ret==0 is caught here.
*/
if (ret != SSL2_HEADERS)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
session->internals.handshake_header_buffer.header_size = SSL2_HEADERS;
}
if (session->internals.v2_hello == 0
|| type != GNUTLS_HANDSHAKE_CLIENT_HELLO)
{
ret =
MHD_gtls_handshake_io_recv_int (session, GNUTLS_HANDSHAKE,
type,
&dataptr
[session->
internals.handshake_header_buffer.
header_size],
HANDSHAKE_HEADER_SIZE -
session->
internals.handshake_header_buffer.
header_size);
if (ret <= 0)
{
MHD_gnutls_assert ();
return (ret < 0) ? ret : GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
if ((size_t) ret !=
HANDSHAKE_HEADER_SIZE -
session->internals.handshake_header_buffer.header_size)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
*recv_type = dataptr[0];
/* we do not use DECR_LEN because we know
* that the packet has enough data.
*/
length32 = MHD_gtls_read_uint24 (&dataptr[1]);
handshake_header_size = HANDSHAKE_HEADER_SIZE;
MHD__gnutls_handshake_log ("HSK[%x]: %s was received [%ld bytes]\n",
session,
MHD__gnutls_handshake2str (dataptr[0]),
length32 + HANDSHAKE_HEADER_SIZE);
}
else
{ /* v2 hello */
length32 = session->internals.v2_hello - SSL2_HEADERS; /* we've read the first byte */
handshake_header_size = SSL2_HEADERS; /* we've already read one byte */
*recv_type = dataptr[0];
MHD__gnutls_handshake_log ("HSK[%x]: %s(v2) was received [%ld bytes]\n",
session,
MHD__gnutls_handshake2str (*recv_type),
length32 + handshake_header_size);
if (*recv_type != GNUTLS_HANDSHAKE_CLIENT_HELLO)
{ /* it should be one or nothing */
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET;
}
}
/* put the packet into the buffer */
session->internals.handshake_header_buffer.header_size =
handshake_header_size;
session->internals.handshake_header_buffer.packet_length = length32;
session->internals.handshake_header_buffer.recv_type = *recv_type;
if (*recv_type != type)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET;
}
return length32;
}
#define MHD__gnutls_handshake_header_buffer_clear( session) session->internals.handshake_header_buffer.header_size = 0
/* This function will hash the handshake headers and the
* handshake data.
*/
static int
MHD__gnutls_handshake_hash_add_recvd (MHD_gtls_session_t session,
MHD_gnutls_handshake_description_t
recv_type, opaque * header,
uint16_t header_size, opaque * dataptr,
uint32_t datalen)
{
int ret;
/* The idea here is to hash the previous message we received,
* and add the one we just received into the handshake_hash_buffer.
*/
if ((ret = MHD__gnutls_handshake_hash_pending (session)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* here we buffer the handshake messages - needed at Finished message */
if (recv_type != GNUTLS_HANDSHAKE_HELLO_REQUEST)
{
if ((ret =
MHD_gtls_handshake_buffer_put (session, header, header_size)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
if (datalen > 0)
{
if ((ret =
MHD_gtls_handshake_buffer_put (session, dataptr, datalen)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
}
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 MHD_gtls_recv_hello().
*/
int
MHD_gtls_recv_handshake (MHD_gtls_session_t session, uint8_t ** data,
int *datalen,
MHD_gnutls_handshake_description_t type,
Optional optional)
{
int ret;
uint32_t length32 = 0;
opaque *dataptr = NULL;
MHD_gnutls_handshake_description_t recv_type;
ret = MHD__gnutls_recv_handshake_header (session, type, &recv_type);
if (ret < 0)
{
if (ret == GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET
&& optional == OPTIONAL_PACKET)
{
if (datalen != NULL)
*datalen = 0;
if (data != NULL)
*data = NULL;
return 0; /* ok just ignore the packet */
}
return ret;
}
session->internals.last_handshake_in = recv_type;
length32 = ret;
if (length32 > 0)
dataptr = MHD_gnutls_malloc (length32);
else if (recv_type != GNUTLS_HANDSHAKE_SERVER_HELLO_DONE)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
if (dataptr == NULL && length32 > 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
if (datalen != NULL)
*datalen = length32;
if (length32 > 0)
{
ret =
MHD_gtls_handshake_io_recv_int (session, GNUTLS_HANDSHAKE,
type, dataptr, length32);
if (ret <= 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (dataptr);
return (ret == 0) ? GNUTLS_E_UNEXPECTED_PACKET_LENGTH : ret;
}
}
if (data != NULL && length32 > 0)
*data = dataptr;
ret = MHD__gnutls_handshake_hash_add_recvd (session, recv_type,
session->
internals.handshake_header_buffer.
header,
session->
internals.handshake_header_buffer.
header_size, dataptr, length32);
if (ret < 0)
{
MHD_gnutls_assert ();
MHD__gnutls_handshake_header_buffer_clear (session);
return ret;
}
/* If we fail before this then we will reuse the handshake header
* have have received above. if we get here the we clear the handshake
* header we received.
*/
MHD__gnutls_handshake_header_buffer_clear (session);
switch (recv_type)
{
case GNUTLS_HANDSHAKE_CLIENT_HELLO:
case GNUTLS_HANDSHAKE_SERVER_HELLO:
ret = MHD_gtls_recv_hello (session, dataptr, length32);
/* dataptr is freed because the caller does not
* need it */
MHD_gnutls_free (dataptr);
if (data != NULL)
*data = NULL;
break;
case GNUTLS_HANDSHAKE_SERVER_HELLO_DONE:
if (length32 == 0)
ret = 0;
else
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
break;
case GNUTLS_HANDSHAKE_CERTIFICATE_PKT:
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:
ret = length32;
break;
default:
MHD_gnutls_assert ();
MHD_gnutls_free (dataptr);
if (data != NULL)
*data = NULL;
ret = GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET;
}
return ret;
}
#if MHD_DEBUG_TLS
/* This function checks if the given cipher suite is supported, and sets it
* to the session;
*/
static int
MHD__gnutls_client_set_ciphersuite (MHD_gtls_session_t session,
opaque suite[2])
{
uint8_t z;
cipher_suite_st *cipher_suites;
int cipher_suite_num;
int i, err;
z = 1;
cipher_suite_num =
MHD_gtls_supported_ciphersuites (session, &cipher_suites);
if (cipher_suite_num < 0)
{
MHD_gnutls_assert ();
return cipher_suite_num;
}
for (i = 0; i < cipher_suite_num; i++)
{
if (memcmp (&cipher_suites[i], suite, 2) == 0)
{
z = 0;
break;
}
}
MHD_gnutls_free (cipher_suites);
if (z != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
}
memcpy (session->security_parameters.current_cipher_suite.suite, suite, 2);
MHD__gnutls_handshake_log ("HSK[%x]: Selected cipher suite: %s\n", session,
MHD_gtls_cipher_suite_get_name
(&session->
security_parameters.current_cipher_suite));
/* check if the credentials (username, public key etc.) are ok.
* Actually checks if they exist.
*/
if (MHD_gtls_get_kx_cred
(session,
MHD_gtls_cipher_suite_get_kx_algo
(&session->security_parameters.current_cipher_suite), &err) == NULL
&& err != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
/* set the MHD_gtls_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 =
MHD_gtls_kx_auth_struct (MHD_gtls_cipher_suite_get_kx_algo
(&session->
security_parameters.current_cipher_suite));
if (session->internals.auth_struct == NULL)
{
MHD__gnutls_handshake_log
("HSK[%x]: Cannot find the appropriate handler for the KX algorithm\n",
session);
MHD_gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
return 0;
}
/* This function sets the given comp method to the session.
*/
static int
MHD__gnutls_client_set_comp_method (MHD_gtls_session_t session,
opaque comp_method)
{
int comp_methods_num;
uint8_t *compression_methods;
int i;
comp_methods_num = MHD_gtls_supported_compression_methods (session,
&compression_methods);
if (comp_methods_num < 0)
{
MHD_gnutls_assert ();
return comp_methods_num;
}
for (i = 0; i < comp_methods_num; i++)
{
if (compression_methods[i] == comp_method)
{
comp_methods_num = 0;
break;
}
}
MHD_gnutls_free (compression_methods);
if (comp_methods_num != 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM;
}
session->internals.compression_method =
MHD_gtls_compression_get_id_from_int (comp_method);
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
MHD__gnutls_client_check_if_resuming (MHD_gtls_session_t session,
opaque * session_id, int session_id_len)
{
opaque buf[2 * TLS_MAX_SESSION_ID_SIZE + 1];
MHD__gnutls_handshake_log ("HSK[%x]: SessionID length: %d\n", session,
session_id_len);
MHD__gnutls_handshake_log ("HSK[%x]: SessionID: %s\n", session,
MHD_gtls_bin2hex (session_id, session_id_len,
(char *) buf, sizeof (buf)));
if (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, TLS_RANDOM_SIZE);
memcpy (session->internals.resumed_security_parameters.client_random,
session->security_parameters.client_random, TLS_RANDOM_SIZE);
session->internals.resumed = RESUME_TRUE; /* we are resuming */
return 0;
}
else
{
/* keep the new session id */
session->internals.resumed = RESUME_FALSE; /* we are not resuming */
session->security_parameters.session_id_size = session_id_len;
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
MHD__gnutls_read_server_hello (MHD_gtls_session_t session,
opaque * data, int datalen)
{
uint8_t session_id_len = 0;
int pos = 0;
int ret = 0;
enum MHD_GNUTLS_Protocol version;
int len = datalen;
if (datalen < 38)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
MHD__gnutls_handshake_log ("HSK[%x]: Server's version: %d.%d\n",
session, data[pos], data[pos + 1]);
DECR_LEN (len, 2);
version = MHD_gtls_version_get (data[pos], data[pos + 1]);
if (MHD_gtls_version_is_supported (session, version) == 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
}
else
{
MHD_gtls_set_current_version (session, version);
}
pos += 2;
DECR_LEN (len, TLS_RANDOM_SIZE);
MHD_gtls_set_server_random (session, &data[pos]);
pos += TLS_RANDOM_SIZE;
/* Read session ID
*/
DECR_LEN (len, 1);
session_id_len = data[pos++];
if (len < session_id_len)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
}
DECR_LEN (len, session_id_len);
/* check if we are resuming and set the appropriate
* values;
*/
if (MHD__gnutls_client_check_if_resuming
(session, &data[pos], session_id_len) == 0)
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 = MHD__gnutls_client_set_ciphersuite (session, &data[pos]);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
pos += 2;
/* move to compression */
DECR_LEN (len, 1);
ret = MHD__gnutls_client_set_comp_method (session, data[pos++]);
if (ret < 0)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM;
}
/* Parse extensions.
*/
if (version >= MHD_GNUTLS_PROTOCOL_TLS1_0)
{
ret = MHD_gtls_parse_extensions (session, EXTENSION_ANY, &data[pos], len); /* len is the rest of the parsed length */
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
return ret;
}
/* This function copies the appropriate ciphersuites to a locally allocated buffer
* Needed in client hello messages. Returns the new data length.
*/
static int
MHD__gnutls_copy_ciphersuites (MHD_gtls_session_t session,
opaque * ret_data, size_t ret_data_size)
{
int ret, i;
cipher_suite_st *cipher_suites;
uint16_t cipher_num;
int datalen, pos;
ret = MHD_gtls_supported_ciphersuites_sorted (session, &cipher_suites);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
/* Here we remove any ciphersuite that does not conform
* the certificate requested, or to the
* authentication requested (eg SRP).
*/
ret =
MHD_gtls_remove_unwanted_ciphersuites (session, &cipher_suites, ret, -1);
if (ret < 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (cipher_suites);
return ret;
}
/* If no cipher suites were enabled.
*/
if (ret == 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (cipher_suites);
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
cipher_num = ret;
cipher_num *= sizeof (uint16_t); /* in order to get bytes */
datalen = pos = 0;
datalen += sizeof (uint16_t) + cipher_num;
if ((size_t) datalen > ret_data_size)
{
MHD_gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
MHD_gtls_write_uint16 (cipher_num, ret_data);
pos += 2;
for (i = 0; i < (cipher_num / 2); i++)
{
memcpy (&ret_data[pos], cipher_suites[i].suite, 2);
pos += 2;
}
MHD_gnutls_free (cipher_suites);
return datalen;
}
/* This function copies the appropriate compression methods, to a locally allocated buffer
* Needed in hello messages. Returns the new data length.
*/
static int
MHD__gnutls_copy_comp_methods (MHD_gtls_session_t session,
opaque * ret_data, size_t ret_data_size)
{
int ret, i;
uint8_t *compression_methods, comp_num;
int datalen, pos;
ret =
MHD_gtls_supported_compression_methods (session, &compression_methods);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
comp_num = ret;
datalen = pos = 0;
datalen += comp_num + 1;
if ((size_t) datalen > ret_data_size)
{
MHD_gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
ret_data[pos++] = comp_num; /* put the number of compression methods */
for (i = 0; i < comp_num; i++)
{
ret_data[pos++] = compression_methods[i];
}
MHD_gnutls_free (compression_methods);
return datalen;
}
static void
MHD_gtls_set_adv_version (MHD_gtls_session_t session,
enum MHD_GNUTLS_Protocol ver)
{
set_adv_version (session, MHD_gtls_version_get_major (ver),
MHD_gtls_version_get_minor (ver));
}
/* This function sends the client hello handshake message.
*/
static int
MHD__gnutls_send_client_hello (MHD_gtls_session_t session, int again)
{
opaque *data = NULL;
int extdatalen;
int pos = 0;
int datalen = 0, ret = 0;
opaque rnd[TLS_RANDOM_SIZE];
enum MHD_GNUTLS_Protocol hver;
opaque extdata[MAX_EXT_DATA_LENGTH];
opaque *SessionID =
session->internals.resumed_security_parameters.session_id;
uint8_t session_id_len =
session->internals.resumed_security_parameters.session_id_size;
if (SessionID == NULL)
session_id_len = 0;
else if (session_id_len == 0)
SessionID = NULL;
if (again == 0)
{
datalen = 2 + (session_id_len + 1) + TLS_RANDOM_SIZE;
/* 2 for version, (4 for unix time + 28 for random bytes==TLS_RANDOM_SIZE)
*/
data = MHD_gnutls_malloc (datalen);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
/* if we are resuming a session then we set the
* version number to the previously established.
*/
if (SessionID == NULL)
hver = MHD_gtls_version_max (session);
else
{ /* we are resuming a session */
hver = session->internals.resumed_security_parameters.version;
}
if (hver == MHD_GNUTLS_PROTOCOL_VERSION_UNKNOWN || hver == 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (data);
return GNUTLS_E_INTERNAL_ERROR;
}
data[pos++] = MHD_gtls_version_get_major (hver);
data[pos++] = MHD_gtls_version_get_minor (hver);
/* Set the version we advertized as maximum
* (RSA uses it).
*/
MHD_gtls_set_adv_version (session, hver);
/* Some old implementations do not interoperate if we send a
* different version in the record layer.
* It seems they prefer to read the record's version
* as the one we actually requested.
* The proper behaviour is to use the one in the client hello
* handshake packet and ignore the one in the packet's record
* header.
*/
MHD_gtls_set_current_version (session, hver);
/* In order to know when this session was initiated.
*/
session->security_parameters.timestamp = time (NULL);
/* Generate random data
*/
MHD_gtls_tls_create_random (rnd);
MHD_gtls_set_client_random (session, rnd);
memcpy (&data[pos], rnd, TLS_RANDOM_SIZE);
pos += TLS_RANDOM_SIZE;
/* Copy the Session ID */
data[pos++] = session_id_len;
if (session_id_len > 0)
{
memcpy (&data[pos], SessionID, session_id_len);
pos += session_id_len;
}
/* Copy the ciphersuites.
*/
extdatalen =
MHD__gnutls_copy_ciphersuites (session, extdata, sizeof (extdata));
if (extdatalen > 0)
{
datalen += extdatalen;
data = MHD_gtls_realloc_fast (data, datalen);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
memcpy (&data[pos], extdata, extdatalen);
pos += extdatalen;
}
else
{
if (extdatalen == 0)
extdatalen = GNUTLS_E_INTERNAL_ERROR;
MHD_gnutls_free (data);
MHD_gnutls_assert ();
return extdatalen;
}
/* Copy the compression methods.
*/
extdatalen =
MHD__gnutls_copy_comp_methods (session, extdata, sizeof (extdata));
if (extdatalen > 0)
{
datalen += extdatalen;
data = MHD_gtls_realloc_fast (data, datalen);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
memcpy (&data[pos], extdata, extdatalen);
pos += extdatalen;
}
else
{
if (extdatalen == 0)
extdatalen = GNUTLS_E_INTERNAL_ERROR;
MHD_gnutls_free (data);
MHD_gnutls_assert ();
return extdatalen;
}
/* Generate and copy TLS extensions.
*/
if (hver >= MHD_GNUTLS_PROTOCOL_TLS1_0)
{
extdatalen =
MHD_gtls_gen_extensions (session, extdata, sizeof (extdata));
if (extdatalen > 0)
{
datalen += extdatalen;
data = MHD_gtls_realloc_fast (data, datalen);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
memcpy (&data[pos], extdata, extdatalen);
}
else if (extdatalen < 0)
{
MHD_gnutls_assert ();
MHD_gnutls_free (data);
return extdatalen;
}
}
}
ret =
MHD_gtls_send_handshake (session, data, datalen,
GNUTLS_HANDSHAKE_CLIENT_HELLO);
MHD_gnutls_free (data);
return ret;
}
#endif
static int
MHD__gnutls_send_server_hello (MHD_gtls_session_t session, int again)
{
opaque *data = NULL;
opaque extdata[MAX_EXT_DATA_LENGTH];
int extdatalen;
int pos = 0;
int datalen, ret = 0;
uint8_t comp;
opaque *SessionID = session->security_parameters.session_id;
uint8_t session_id_len = session->security_parameters.session_id_size;
opaque buf[2 * TLS_MAX_SESSION_ID_SIZE + 1];
if (SessionID == NULL)
session_id_len = 0;
datalen = 0;
if (again == 0)
{
datalen = 2 + session_id_len + 1 + TLS_RANDOM_SIZE + 3;
extdatalen =
MHD_gtls_gen_extensions (session, extdata, sizeof (extdata));
if (extdatalen < 0)
{
MHD_gnutls_assert ();
return extdatalen;
}
data = MHD_gnutls_alloca (datalen + extdatalen);
if (data == NULL)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
data[pos++] =
MHD_gtls_version_get_major (session->security_parameters.version);
data[pos++] =
MHD_gtls_version_get_minor (session->security_parameters.version);
memcpy (&data[pos],
session->security_parameters.server_random, TLS_RANDOM_SIZE);
pos += TLS_RANDOM_SIZE;
data[pos++] = session_id_len;
if (session_id_len > 0)
{
memcpy (&data[pos], SessionID, session_id_len);
}
pos += session_id_len;
MHD__gnutls_handshake_log ("HSK[%x]: SessionID: %s\n", session,
MHD_gtls_bin2hex (SessionID, session_id_len,
(char *) buf,
sizeof (buf)));
memcpy (&data[pos],
session->security_parameters.current_cipher_suite.suite, 2);
pos += 2;
comp =
(uint8_t) MHD_gtls_compression_get_num (session->internals.
compression_method);
data[pos++] = comp;
if (extdatalen > 0)
{
datalen += extdatalen;
memcpy (&data[pos], extdata, extdatalen);
}
}
ret =
MHD_gtls_send_handshake (session, data, datalen,
GNUTLS_HANDSHAKE_SERVER_HELLO);
MHD_gnutls_afree (data);
return ret;
}
int
MHD_gtls_send_hello (MHD_gtls_session_t session, int again)
{
int ret;
#if MHD_DEBUG_TLS
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
ret = MHD__gnutls_send_client_hello (session, again);
}
else
#endif
{ /* SERVER */
ret = MHD__gnutls_send_server_hello (session, again);
}
return ret;
}
/* RECEIVE A HELLO MESSAGE. This should be called from MHD_gnutls_recv_handshake_int only if a
* hello message is expected. It uses the security_parameters.current_cipher_suite
* and internals.compression_method.
*/
int
MHD_gtls_recv_hello (MHD_gtls_session_t session, opaque * data, int datalen)
{
int ret;
#if MHD_DEBUG_TLS
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
ret = MHD__gnutls_read_server_hello (session, data, datalen);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
else
#endif
{ /* Server side reading a client hello */
ret = MHD__gnutls_read_client_hello (session, data, datalen);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
return ret;
}
/* The packets in MHD__gnutls_handshake (it's more broad than original TLS handshake)
*
* Client Server
*
* ClientHello -------->
* <-------- ServerHello
*
* Certificate*
* ServerKeyExchange*
* <-------- CertificateRequest*
*
* <-------- ServerHelloDone
* Certificate*
* ClientKeyExchange
* CertificateVerify*
* [ChangeCipherSpec]
* Finished -------->
* [ChangeCipherSpec]
* <-------- Finished
*
* (*): means optional packet.
*/
/**
* MHD__gnutls_rehandshake - This function will renegotiate security parameters
* @session: is a #MHD_gtls_session_t structure.
*
* 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
* MHD__gnutls_handshake() function in order to negotiate the new
* parameters.
*
* If the client does not wish to renegotiate parameters he will
* should 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 an error.
*
**/
int
MHD__gnutls_rehandshake (MHD_gtls_session_t session)
{
int ret;
ret =
MHD__gnutls_send_empty_handshake (session, GNUTLS_HANDSHAKE_HELLO_REQUEST,
AGAIN (STATE50));
STATE = STATE50;
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
STATE = STATE0;
return 0;
}
inline static int
MHD__gnutls_abort_handshake (MHD_gtls_session_t session, int ret)
{
if (((ret == GNUTLS_E_WARNING_ALERT_RECEIVED) &&
(MHD_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;
}
/* This function initialized the handshake hash session.
* required for finished messages.
*/
inline static int
MHD__gnutls_handshake_hash_init (MHD_gtls_session_t session)
{
if (session->internals.handshake_mac_handle_md5 == NULL)
{
session->internals.handshake_mac_handle_md5 =
MHD_gtls_hash_init (MHD_GNUTLS_MAC_MD5);
if (session->internals.handshake_mac_handle_md5 == GNUTLS_HASH_FAILED)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
}
if (session->internals.handshake_mac_handle_sha == NULL)
{
session->internals.handshake_mac_handle_sha =
MHD_gtls_hash_init (MHD_GNUTLS_MAC_SHA1);
if (session->internals.handshake_mac_handle_sha == GNUTLS_HASH_FAILED)
{
MHD_gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
}
return 0;
}
static int
MHD__gnutls_send_supplemental (MHD_gtls_session_t session, int again)
{
int ret = 0;
MHD__gnutls_debug_log ("EXT[%x]: Sending supplemental data\n", session);
if (again)
ret = MHD_gtls_send_handshake (session, NULL, 0,
GNUTLS_HANDSHAKE_SUPPLEMENTAL);
else
{
MHD_gtls_buffer buf;
MHD_gtls_buffer_init (&buf);
ret = MHD__gnutls_gen_supplemental (session, &buf);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
ret = MHD_gtls_send_handshake (session, buf.data, buf.length,
GNUTLS_HANDSHAKE_SUPPLEMENTAL);
MHD_gtls_buffer_clear (&buf);
}
return ret;
}
static int
MHD__gnutls_recv_supplemental (MHD_gtls_session_t session)
{
uint8_t *data = NULL;
int datalen = 0;
int ret;
MHD__gnutls_debug_log ("EXT[%x]: Expecting supplemental data\n", session);
ret = MHD_gtls_recv_handshake (session, &data, &datalen,
GNUTLS_HANDSHAKE_SUPPLEMENTAL,
OPTIONAL_PACKET);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
ret = MHD__gnutls_parse_supplemental (session, data, datalen);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
MHD_gnutls_free (data);
return ret;
}
/**
* MHD__gnutls_handshake - This is the main function in the handshake protocol.
* @session: is a #MHD_gtls_session_t structure.
*
* 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 such as %GNUTLS_E_AGAIN and
* %GNUTLS_E_INTERRUPTED interrupt the handshake procedure, which
* should be later be resumed. Call this function again, until it
* returns 0; cf. MHD__gnutls_record_get_direction() and
* MHD_gtls_error_is_fatal().
*
* 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.
*
* Returns: %GNUTLS_E_SUCCESS on success, otherwise an error.
*
**/
int
MHD__gnutls_handshake (MHD_gtls_session_t session)
{
int ret;
if ((ret = MHD__gnutls_handshake_hash_init (session)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
#if MHD_DEBUG_TLS
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
ret = MHD_gtls_handshake_client (session);
}
else
#endif
{
ret = MHD_gtls_handshake_server (session);
}
if (ret < 0)
{
/* In the case of a rehandshake abort
* we should reset the handshake's internal state.
*/
if (MHD__gnutls_abort_handshake (session, ret) == 0)
STATE = STATE0;
return ret;
}
ret = MHD_gtls_handshake_common (session);
if (ret < 0)
{
if (MHD__gnutls_abort_handshake (session, ret) == 0)
STATE = STATE0;
return ret;
}
STATE = STATE0;
MHD__gnutls_handshake_io_buffer_clear (session);
MHD_gtls_handshake_internal_state_clear (session);
return 0;
}
#define IMED_RET( str, ret) do { \
if (ret < 0) { \
if (MHD_gtls_error_is_fatal(ret)==0) return ret; \
MHD_gnutls_assert(); \
ERR( str, ret); \
MHD__gnutls_handshake_hash_buffers_clear(session); \
return ret; \
} } while (0)
#if MHD_DEBUG_TLS
/*
* MHD_gtls_handshake_client
* This function performs the client side of the handshake of the TLS/SSL protocol.
*/
static int
MHD_gtls_handshake_client (MHD_gtls_session_t session)
{
int ret = 0;
#ifdef HANDSHAKE_DEBUG
char buf[64];
if (session->internals.resumed_security_parameters.session_id_size > 0)
MHD__gnutls_handshake_log ("HSK[%x]: Ask to resume: %s\n", session,
MHD_gtls_bin2hex (session->
internals.resumed_security_parameters.session_id,
session->
internals.resumed_security_parameters.session_id_size,
buf, sizeof (buf)));
#endif
switch (STATE)
{
case STATE0:
case STATE1:
ret = MHD_gtls_send_hello (session, AGAIN (STATE1));
STATE = STATE1;
IMED_RET ("send hello", ret);
case STATE2:
/* receive the server hello */
ret =
MHD_gtls_recv_handshake (session, NULL, NULL,
GNUTLS_HANDSHAKE_SERVER_HELLO,
MANDATORY_PACKET);
STATE = STATE2;
IMED_RET ("recv hello", ret);
case STATE70:
if (session->security_parameters.extensions.do_recv_supplemental)
{
ret = MHD__gnutls_recv_supplemental (session);
STATE = STATE70;
IMED_RET ("recv supplemental", ret);
}
case STATE3:
/* RECV CERTIFICATE */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_server_certificate (session);
STATE = STATE3;
IMED_RET ("recv server certificate", ret);
case STATE4:
/* receive the server key exchange */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_server_kx_message (session);
STATE = STATE4;
IMED_RET ("recv server kx message", ret);
case STATE5:
/* receive the server certificate request - if any
*/
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_server_certificate_request (session);
STATE = STATE5;
IMED_RET ("recv server certificate request message", ret);
case STATE6:
/* receive the server hello done */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
MHD_gtls_recv_handshake (session, NULL, NULL,
GNUTLS_HANDSHAKE_SERVER_HELLO_DONE,
MANDATORY_PACKET);
STATE = STATE6;
IMED_RET ("recv server hello done", ret);
case STATE71:
if (session->security_parameters.extensions.do_send_supplemental)
{
ret = MHD__gnutls_send_supplemental (session, AGAIN (STATE71));
STATE = STATE71;
IMED_RET ("send supplemental", ret);
}
case STATE7:
/* send our certificate - if any and if requested
*/
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_send_client_certificate (session, AGAIN (STATE7));
STATE = STATE7;
IMED_RET ("send client certificate", ret);
case STATE8:
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_send_client_kx_message (session, AGAIN (STATE8));
STATE = STATE8;
IMED_RET ("send client kx", ret);
case STATE9:
/* send client certificate verify */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
MHD_gtls_send_client_certificate_verify (session, AGAIN (STATE9));
STATE = STATE9;
IMED_RET ("send client certificate verify", ret);
STATE = STATE0;
default:
break;
}
return 0;
}
#endif
/* This function sends the final handshake packets and initializes connection
*/
static int
MHD__gnutls_send_handshake_final (MHD_gtls_session_t session, int init)
{
int ret = 0;
/* Send the CHANGE CIPHER SPEC PACKET */
switch (STATE)
{
case STATE0:
case STATE20:
ret = MHD_gtls_send_change_cipher_spec (session, AGAIN (STATE20));
STATE = STATE20;
if (ret < 0)
{
ERR ("send ChangeCipherSpec", ret);
MHD_gnutls_assert ();
return ret;
}
/* Initialize the connection session (start encryption) - in case of client
*/
if (init == TRUE)
{
ret = MHD_gtls_connection_state_init (session);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
ret = MHD_gtls_write_connection_state_init (session);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
case STATE21:
/* send the finished message */
ret = MHD__gnutls_send_finished (session, AGAIN (STATE21));
STATE = STATE21;
if (ret < 0)
{
ERR ("send Finished", ret);
MHD_gnutls_assert ();
return ret;
}
STATE = STATE0;
default:
break;
}
return 0;
}
/* This function receives the final handshake packets
* And executes the appropriate function to initialize the
* read session.
*/
static int
MHD__gnutls_recv_handshake_final (MHD_gtls_session_t session, int init)
{
int ret = 0;
uint8_t ch;
switch (STATE)
{
case STATE0:
case STATE30:
ret =
MHD_gtls_recv_int (session, GNUTLS_CHANGE_CIPHER_SPEC, -1, &ch, 1);
STATE = STATE30;
if (ret <= 0)
{
ERR ("recv ChangeCipherSpec", ret);
MHD_gnutls_assert ();
return (ret < 0) ? ret : GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
/* Initialize the connection session (start encryption) - in case of server */
if (init == TRUE)
{
ret = MHD_gtls_connection_state_init (session);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
}
ret = MHD_gtls_read_connection_state_init (session);
if (ret < 0)
{
MHD_gnutls_assert ();
return ret;
}
case STATE31:
ret = MHD__gnutls_recv_finished (session);
STATE = STATE31;
if (ret < 0)
{
ERR ("recv finished", ret);
MHD_gnutls_assert ();
return ret;
}
STATE = STATE0;
default:
break;
}
return 0;
}
/*
* MHD_gtls_handshake_server
* This function does the server stuff of the handshake protocol.
*/
static int
MHD_gtls_handshake_server (MHD_gtls_session_t session)
{
int ret = 0;
switch (STATE)
{
case STATE0:
case STATE1:
ret =
MHD_gtls_recv_handshake (session, NULL, NULL,
GNUTLS_HANDSHAKE_CLIENT_HELLO,
MANDATORY_PACKET);
STATE = STATE1;
IMED_RET ("recv hello", ret);
case STATE2:
ret = MHD_gtls_send_hello (session, AGAIN (STATE2));
STATE = STATE2;
IMED_RET ("send hello", ret);
case STATE70:
if (session->security_parameters.extensions.do_send_supplemental)
{
ret = MHD__gnutls_send_supplemental (session, AGAIN (STATE70));
STATE = STATE70;
IMED_RET ("send supplemental data", ret);
}
/* SEND CERTIFICATE + KEYEXCHANGE + CERTIFICATE_REQUEST */
case STATE3:
/* NOTE: these should not be send if we are resuming */
if (session->internals.resumed == RESUME_FALSE)
ret = MHD_gtls_send_server_certificate (session, AGAIN (STATE3));
STATE = STATE3;
IMED_RET ("send server certificate", ret);
case STATE4:
/* send server key exchange (A) */
if (session->internals.resumed == RESUME_FALSE)
ret = MHD_gtls_send_server_kx_message (session, AGAIN (STATE4));
STATE = STATE4;
IMED_RET ("send server kx", ret);
case STATE5:
/* Send certificate request - if requested to */
if (session->internals.resumed == RESUME_FALSE)
ret =
MHD_gtls_send_server_certificate_request (session, AGAIN (STATE5));
STATE = STATE5;
IMED_RET ("send server cert request", ret);
case STATE6:
/* send the server hello done */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret =
MHD__gnutls_send_empty_handshake (session,
GNUTLS_HANDSHAKE_SERVER_HELLO_DONE,
AGAIN (STATE6));
STATE = STATE6;
IMED_RET ("send server hello done", ret);
case STATE71:
if (session->security_parameters.extensions.do_recv_supplemental)
{
ret = MHD__gnutls_recv_supplemental (session);
STATE = STATE71;
IMED_RET ("recv client supplemental", ret);
}
/* RECV CERTIFICATE + KEYEXCHANGE + CERTIFICATE_VERIFY */
case STATE7:
/* receive the client certificate message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_client_certificate (session);
STATE = STATE7;
IMED_RET ("recv client certificate", ret);
case STATE8:
/* receive the client key exchange message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_client_kx_message (session);
STATE = STATE8;
IMED_RET ("recv client kx", ret);
case STATE9:
/* receive the client certificate verify message */
if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */
ret = MHD_gtls_recv_client_certificate_verify_message (session);
STATE = STATE9;
IMED_RET ("recv client certificate verify", ret);
STATE = STATE0; /* finished thus clear session */
default:
break;
}
return 0;
}
static int
MHD_gtls_handshake_common (MHD_gtls_session_t session)
{
int ret = 0;
/* send and recv the change cipher spec and finished messages */
if ((session->internals.resumed == RESUME_TRUE
&& 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 */
ret = MHD__gnutls_recv_handshake_final (session, TRUE);
IMED_RET ("recv handshake final", ret);
ret = MHD__gnutls_send_handshake_final (session, FALSE);
IMED_RET ("send handshake final", ret);
}
else
{ /* if we are a client not resuming - or we are a server resuming */
ret = MHD__gnutls_send_handshake_final (session, TRUE);
IMED_RET ("send handshake final 2", ret);
ret = MHD__gnutls_recv_handshake_final (session, FALSE);
IMED_RET ("recv handshake final 2", ret);
}
/* clear handshake buffer */
MHD__gnutls_handshake_hash_buffers_clear (session);
return ret;
}
static int
MHD_gtls_generate_session_id (opaque * session_id, uint8_t * len)
{
*len = TLS_MAX_SESSION_ID_SIZE;
if (MHD_gc_nonce ((char *) session_id, *len) != GC_OK)
{
MHD_gnutls_assert ();
return GNUTLS_E_RANDOM_FAILED;
}
return 0;
}
int
MHD_gtls_recv_hello_request (MHD_gtls_session_t session, void *data,
uint32_t data_size)
{
uint8_t type;
if (session->security_parameters.entity == GNUTLS_SERVER)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET;
}
if (data_size < 1)
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
type = ((uint8_t *) data)[0];
if (type == GNUTLS_HANDSHAKE_HELLO_REQUEST)
return GNUTLS_E_REHANDSHAKE;
else
{
MHD_gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET;
}
}
/* Returns 1 if the given KX has not the corresponding parameters
* (DH or RSA) set up. Otherwise returns 0.
*/
inline static int
check_server_params (MHD_gtls_session_t session,
enum MHD_GNUTLS_KeyExchangeAlgorithm kx,
enum MHD_GNUTLS_KeyExchangeAlgorithm *alg, int alg_size)
{
int cred_type;
MHD_gtls_dh_params_t dh_params = NULL;
MHD_gtls_rsa_params_t rsa_params = NULL;
int j;
cred_type = MHD_gtls_map_kx_get_cred (kx, 1);
/* Read the Diffie Hellman parameters, if any.
*/
if (cred_type == MHD_GNUTLS_CRD_CERTIFICATE)
{
int delete;
MHD_gtls_cert_credentials_t x509_cred =
(MHD_gtls_cert_credentials_t) MHD_gtls_get_cred (session->key,
cred_type, NULL);
if (x509_cred != NULL)
{
dh_params =
MHD_gtls_get_dh_params (x509_cred->dh_params,
x509_cred->params_func, session);
rsa_params =
MHD_gtls_certificate_get_rsa_params (x509_cred->rsa_params,
x509_cred->params_func,
session);
}
/* Check also if the certificate supports the
* KX method.
*/
delete = 1;
for (j = 0; j < alg_size; j++)
{
if (alg[j] == kx)
{
delete = 0;
break;
}
}
if (delete == 1)
return 1;
}
else
return 0; /* no need for params */
/* If the key exchange method needs RSA or DH params,
* but they are not set then remove it.
*/
if (MHD_gtls_kx_needs_rsa_params (kx) != 0)
{
/* needs rsa params. */
if (MHD__gnutls_rsa_params_to_mpi (rsa_params) == NULL)
{
MHD_gnutls_assert ();
return 1;
}
}
if (MHD_gtls_kx_needs_dh_params (kx) != 0)
{
/* needs DH params. */
if (MHD_gtls_dh_params_to_mpi (dh_params) == NULL)
{
MHD_gnutls_assert ();
return 1;
}
}
return 0;
}
/* This function will remove algorithms that are not supported by
* the requested authentication method. We remove an algorithm if
* we have a certificate with keyUsage bits set.
*
* This does a more high level check than MHD_gnutls_supported_ciphersuites(),
* by checking certificates etc.
*/
static int
MHD_gtls_remove_unwanted_ciphersuites (MHD_gtls_session_t session,
cipher_suite_st ** cipherSuites,
int numCipherSuites,
enum MHD_GNUTLS_PublicKeyAlgorithm
requested_pk_algo)
{
int ret = 0;
cipher_suite_st *newSuite, cs;
int newSuiteSize = 0, i;
MHD_gtls_cert_credentials_t cert_cred;
enum MHD_GNUTLS_KeyExchangeAlgorithm kx;
int server = session->security_parameters.entity == GNUTLS_SERVER ? 1 : 0;
enum MHD_GNUTLS_KeyExchangeAlgorithm *alg = NULL;
int alg_size = 0;
/* if we should use a specific certificate,
* we should remove all algorithms that are not supported
* by that certificate and are on the same authentication
* method (CERTIFICATE).
*/
cert_cred =
(MHD_gtls_cert_credentials_t) MHD_gtls_get_cred (session->key,
MHD_GNUTLS_CRD_CERTIFICATE,
NULL);
/* If there are certificate credentials, find an appropriate certificate
* or disable them;
*/
if (session->security_parameters.entity == GNUTLS_SERVER
&& cert_cred != NULL)
{
ret = MHD_gtls_server_select_cert (session, requested_pk_algo);
if (ret < 0)
{
MHD_gnutls_assert ();
MHD__gnutls_x509_log
("Could not find an appropriate certificate: %s\n",
MHD_gtls_strerror (ret));
cert_cred = NULL;
}
}
/* get all the key exchange algorithms that are
* supported by the X509 certificate parameters.
*/
if ((ret =
MHD_gtls_selected_cert_supported_kx (session, &alg, &alg_size)) < 0)
{
MHD_gnutls_assert ();
return ret;
}
newSuite = MHD_gnutls_malloc (numCipherSuites * sizeof (cipher_suite_st));
if (newSuite == NULL)
{
MHD_gnutls_assert ();
MHD_gnutls_free (alg);
return GNUTLS_E_MEMORY_ERROR;
}
/* now removes ciphersuites based on the KX algorithm
*/
for (i = 0; i < numCipherSuites; i++)
{
int delete = 0;
/* finds the key exchange algorithm in
* the ciphersuite
*/
kx = MHD_gtls_cipher_suite_get_kx_algo (&(*cipherSuites)[i]);
/* if it is defined but had no credentials
*/
if (MHD_gtls_get_kx_cred (session, kx, NULL) == NULL)
{
delete = 1;
}
else
{
delete = 0;
if (server)
delete = check_server_params (session, kx, alg, alg_size);
}
/* These two SRP kx's are marked to require a CRD_CERTIFICATE,
(see cred_mappings in MHD_gnutls_algorithms.c), but it also
requires a SRP credential. Don't use SRP kx unless we have a
SRP credential too. */
if (kx == MHD_GNUTLS_KX_SRP_RSA || kx == MHD_GNUTLS_KX_SRP_DSS)
{
delete = 1;
}
memcpy (&cs.suite, &(*cipherSuites)[i].suite, 2);
if (delete == 0)
{
MHD__gnutls_handshake_log ("HSK[%x]: Keeping ciphersuite: %s\n",
session,
MHD_gtls_cipher_suite_get_name (&cs));
memcpy (newSuite[newSuiteSize].suite, (*cipherSuites)[i].suite, 2);
newSuiteSize++;
}
else
{
MHD__gnutls_handshake_log ("HSK[%x]: Removing ciphersuite: %s\n",
session,
MHD_gtls_cipher_suite_get_name (&cs));
}
}
MHD_gnutls_free (alg);
MHD_gnutls_free (*cipherSuites);
*cipherSuites = newSuite;
ret = newSuiteSize;
return ret;
}
enum MHD_GNUTLS_Protocol
MHD_gtls_get_adv_version (MHD_gtls_session_t session)
{
return MHD_gtls_version_get (MHD__gnutls_get_adv_version_major (session),
MHD__gnutls_get_adv_version_minor (session));
}
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