/* * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation * * Author: Nikos Mavroyanopoulos * * 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 "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_db.h" #include "gnutls_extensions.h" #include "gnutls_auth_int.h" #include "gnutls_v2_compat.h" #include "auth_cert.h" #include "gnutls_cert.h" #include "gnutls_constate.h" #include #include #include #include /* for gnutls_get_rsa_params() */ #include /* for gnutls_anon_server_credentials_t */ #include #ifdef HANDSHAKE_DEBUG #define ERR(x, y) _gnutls_handshake_log( "HSK[%x]: %s (%d)\n", session, x,y) #else #define ERR(x, y) #endif #define TRUE 1 #define FALSE 0 int _gnutls_server_select_comp_method (gnutls_session_t session, opaque * data, int datalen); /* Clears the handshake hash buffers and handles. */ inline static void _gnutls_handshake_hash_buffers_clear (gnutls_session_t session) { _gnutls_hash_deinit (session->internals.handshake_mac_handle_md5, NULL); _gnutls_hash_deinit (session->internals.handshake_mac_handle_sha, NULL); session->internals.handshake_mac_handle_md5 = NULL; session->internals.handshake_mac_handle_sha = NULL; _gnutls_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 (gnutls_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; _gnutls_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; } void _gnutls_set_server_random (gnutls_session_t session, uint8 * rnd) { memcpy (session->security_parameters.server_random, rnd, TLS_RANDOM_SIZE); } void _gnutls_set_client_random (gnutls_session_t session, uint8 * 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 _gnutls_ssl3_finished (gnutls_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 = _gnutls_hash_copy (session->internals.handshake_mac_handle_md5); if (td_md5 == NULL) { gnutls_assert (); return GNUTLS_E_HASH_FAILED; } td_sha = _gnutls_hash_copy (session->internals.handshake_mac_handle_sha); if (td_sha == NULL) { gnutls_assert (); _gnutls_hash_deinit (td_md5, NULL); return GNUTLS_E_HASH_FAILED; } if (type == GNUTLS_SERVER) { mesg = SSL3_SERVER_MSG; } else { mesg = SSL3_CLIENT_MSG; } _gnutls_hash (td_md5, mesg, siz); _gnutls_hash (td_sha, mesg, siz); _gnutls_mac_deinit_ssl3_handshake (td_md5, ret, session->security_parameters. master_secret, TLS_MASTER_SIZE); _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 int _gnutls_finished (gnutls_session_t session, int type, void *ret) { const int siz = TLS_MSG_LEN; opaque concat[36]; const char *mesg; mac_hd_t td_md5; mac_hd_t td_sha; td_md5 = _gnutls_hash_copy (session->internals.handshake_mac_handle_md5); if (td_md5 == NULL) { gnutls_assert (); return GNUTLS_E_HASH_FAILED; } td_sha = _gnutls_hash_copy (session->internals.handshake_mac_handle_sha); if (td_sha == NULL) { gnutls_assert (); _gnutls_hash_deinit (td_md5, NULL); return GNUTLS_E_HASH_FAILED; } _gnutls_hash_deinit (td_md5, concat); _gnutls_hash_deinit (td_sha, &concat[16]); if (type == GNUTLS_SERVER) { mesg = SERVER_MSG; } else { mesg = CLIENT_MSG; } return _gnutls_PRF (session->security_parameters.master_secret, TLS_MASTER_SIZE, mesg, siz, concat, 36, 12, ret); } /* this function will produce TLS_RANDOM_SIZE==32 bytes of random data * and put it to dst. */ int _gnutls_tls_create_random (opaque * dst) { uint32 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 */ _gnutls_write_uint32 (tim, dst); if (gc_nonce (&dst[4], TLS_RANDOM_SIZE - 4) != GC_OK) { gnutls_assert (); return GNUTLS_E_RANDOM_FAILED; } 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). */ int _gnutls_read_client_hello (gnutls_session_t session, opaque * data, int datalen) { uint8 session_id_len, z; int pos = 0, ret; uint16 suite_size; gnutls_protocol_t version; int len = datalen; opaque rnd[TLS_RANDOM_SIZE], *suite_ptr; gnutls_protocol_t ver; if (session->internals.v2_hello != 0) { /* version 2.0 */ return _gnutls_read_client_hello_v2 (session, data, datalen); } DECR_LEN (len, 2); _gnutls_handshake_log ("HSK[%x]: Client's version: %d.%d\n", session, data[pos], data[pos + 1]); version = _gnutls_version_get (data[pos], data[pos + 1]); set_adv_version (session, data[pos], data[pos + 1]); pos += 2; /* if we do not support that version */ if (_gnutls_version_is_supported (session, version) == 0) { /* If he requested something we do not support * then we send him the highest we support. */ ver = _gnutls_version_max (session); if (ver == GNUTLS_VERSION_UNKNOWN) { /* this check is not really needed. */ gnutls_assert (); return GNUTLS_E_UNKNOWN_CIPHER_SUITE; } } else { ver = version; } _gnutls_set_current_version (session, ver); /* Read client random value. */ DECR_LEN (len, TLS_RANDOM_SIZE); _gnutls_set_client_random (session, &data[pos]); pos += TLS_RANDOM_SIZE; _gnutls_tls_create_random (rnd); _gnutls_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) { gnutls_assert (); return GNUTLS_E_UNEXPECTED_PACKET_LENGTH; } DECR_LEN (len, session_id_len); ret = _gnutls_server_restore_session (session, &data[pos], session_id_len); pos += session_id_len; if (ret == 0) { /* resumed! */ resume_copy_required_values (session); session->internals.resumed = RESUME_TRUE; return 0; } else { _gnutls_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 = _gnutls_read_uint16 (&data[pos]); pos += 2; DECR_LEN (len, suite_size); suite_ptr = &data[pos]; pos += suite_size; /* Select an appropriate compression method */ DECR_LEN (len, 1); z = data[pos++]; /* z is the number of compression methods */ DECR_LEN (len, z); ret = _gnutls_server_select_comp_method (session, &data[pos], z); pos += z; if (ret < 0) { gnutls_assert (); return ret; } /* Parse the extensions (if any) */ if (ver >= GNUTLS_TLS1) { ret = _gnutls_parse_extensions (session, &data[pos], len); /* len is the rest of the parsed length */ if (ret < 0) { gnutls_assert (); return ret; } } /* select an appropriate cipher suite */ ret = _gnutls_server_select_suite (session, suite_ptr, suite_size); if (ret < 0) { gnutls_assert (); return ret; } return 0; } /* here we hash all pending data. */ inline static int _gnutls_handshake_hash_pending (gnutls_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) { gnutls_assert (); return GNUTLS_E_INTERNAL_ERROR; } /* We check if there are pending data to hash. */ if ((ret = _gnutls_handshake_buffer_get_ptr (session, &data, &siz)) < 0) { gnutls_assert (); return ret; } if (siz > 0) { _gnutls_hash (session->internals.handshake_mac_handle_sha, data, siz); _gnutls_hash (session->internals.handshake_mac_handle_md5, data, siz); } _gnutls_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. */ int _gnutls_send_finished (gnutls_session_t session, int again) { uint8 data[36]; int ret; int data_size = 0; if (again == 0) { /* This is needed in order to hash all the required * messages. */ if ((ret = _gnutls_handshake_hash_pending (session)) < 0) { gnutls_assert (); return ret; } if (gnutls_protocol_get_version (session) == GNUTLS_SSL3) { ret = _gnutls_ssl3_finished (session, session->security_parameters.entity, data); data_size = 36; } else { /* TLS 1.0 */ ret = _gnutls_finished (session, session->security_parameters.entity, data); data_size = 12; } if (ret < 0) { gnutls_assert (); return ret; } } ret = _gnutls_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 */ int _gnutls_recv_finished (gnutls_session_t session) { uint8 data[36], *vrfy; int data_size; int ret; int vrfysize; ret = _gnutls_recv_handshake (session, &vrfy, &vrfysize, GNUTLS_HANDSHAKE_FINISHED, MANDATORY_PACKET); if (ret < 0) { ERR ("recv finished int", ret); gnutls_assert (); return ret; } if (gnutls_protocol_get_version (session) == GNUTLS_SSL3) { data_size = 36; } else { data_size = 12; } if (vrfysize != data_size) { gnutls_assert (); gnutls_free (vrfy); return GNUTLS_E_ERROR_IN_FINISHED_PACKET; } if (gnutls_protocol_get_version (session) == GNUTLS_SSL3) { ret = _gnutls_ssl3_finished (session, (session->security_parameters. entity + 1) % 2, data); } else { /* TLS 1.0 */ ret = _gnutls_finished (session, (session->security_parameters.entity + 1) % 2, data); } if (ret < 0) { gnutls_assert (); gnutls_free (vrfy); return ret; } if (memcmp (vrfy, data, data_size) != 0) { gnutls_assert (); ret = GNUTLS_E_ERROR_IN_FINISHED_PACKET; } 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 _gnutls_server_find_pk_algos_in_ciphersuites (const opaque * data, int datalen) { int j; gnutls_pk_algorithm_t algo = GNUTLS_PK_NONE, prev_algo = 0; gnutls_kx_algorithm_t kx; cipher_suite_st cs; if (datalen % 2 != 0) { gnutls_assert (); return GNUTLS_E_UNEXPECTED_PACKET_LENGTH; } for (j = 0; j < datalen; j += 2) { memcpy (&cs.suite, &data[j], 2); kx = _gnutls_cipher_suite_get_kx_algo (&cs); if (_gnutls_map_kx_get_cred (kx, 1) == GNUTLS_CRD_CERTIFICATE) { algo = _gnutls_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. */ int _gnutls_server_select_suite (gnutls_session_t session, opaque * data, int datalen) { int x, i, j; cipher_suite_st *ciphers, cs; int retval, err; gnutls_pk_algorithm_t pk_algo; /* will hold the pk algorithms * supported by the peer. */ pk_algo = _gnutls_server_find_pk_algos_in_ciphersuites (data, datalen); x = _gnutls_supported_ciphersuites (session, &ciphers); if (x < 0) { /* the case x==0 is handled within the function. */ 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 = _gnutls_remove_unwanted_ciphersuites (session, &ciphers, x, pk_algo); if (x <= 0) { gnutls_assert (); 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) { gnutls_assert (); return GNUTLS_E_UNEXPECTED_PACKET_LENGTH; } #ifdef HANDSHAKE_DEBUG _gnutls_handshake_log ("HSK[%x]: Requested cipher suites: \n", session); for (j = 0; j < datalen; j += 2) { memcpy (&cs.suite, &data[j], 2); _gnutls_handshake_log ("\t%s\n", _gnutls_cipher_suite_get_name (&cs)); } _gnutls_handshake_log ("HSK[%x]: Supported cipher suites: \n", session); for (j = 0; j < x; j++) _gnutls_handshake_log ("\t%s\n", _gnutls_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); _gnutls_handshake_log ("HSK[%x]: Selected cipher suite: %s\n", session, _gnutls_cipher_suite_get_name (&cs)); memcpy (session->security_parameters.current_cipher_suite. suite, ciphers[i].suite, 2); retval = 0; goto finish; } } } finish: gnutls_free (ciphers); if (retval != 0) { gnutls_assert (); return retval; } /* check if the credentials (username, public key etc.) are ok */ if (_gnutls_get_kx_cred (session, _gnutls_cipher_suite_get_kx_algo (&session->security_parameters. current_cipher_suite), &err) == NULL && err != 0) { 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 (_gnutls_cipher_suite_get_kx_algo (&session->security_parameters. current_cipher_suite)); if (session->internals.auth_struct == NULL) { _gnutls_handshake_log ("HSK[%x]: Cannot find the appropriate handler for the KX algorithm\n", session); gnutls_assert (); return GNUTLS_E_INTERNAL_ERROR; } return 0; } /* This selects the best supported compression method from the ones provided */ int _gnutls_server_select_comp_method (gnutls_session_t session, opaque * data, int datalen) { int x, i, j; uint8 *comps; x = _gnutls_supported_compression_methods (session, &comps); if (x < 0) { gnutls_assert (); return x; } memset (&session->internals.compression_method, 0, sizeof (gnutls_compression_method_t)); for (j = 0; j < datalen; j++) { for (i = 0; i < x; i++) { if (comps[i] == data[j]) { gnutls_compression_method_t method = _gnutls_compression_get_id (comps[i]); session->internals.compression_method = method; gnutls_free (comps); _gnutls_handshake_log ("HSK[%x]: Selected Compression Method: %s\n", session, gnutls_compression_get_name (session->internals. compression_method)); return 0; } } } /* we were not able to find a compatible compression * algorithm */ gnutls_free (comps); 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. */ int _gnutls_send_empty_handshake (gnutls_session_t session, gnutls_handshake_description_t type, int again) { opaque data = 0; opaque *ptr; if (again == 0) ptr = &data; else ptr = NULL; return _gnutls_send_handshake (session, ptr, 0, type); } /* This function will hash the handshake message we sent. */ static int _gnutls_handshake_hash_add_sent (gnutls_session_t session, gnutls_handshake_description_t type, opaque * dataptr, uint32 datalen) { int ret; if ((ret = _gnutls_handshake_hash_pending (session)) < 0) { gnutls_assert (); return ret; } if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST) { _gnutls_hash (session->internals.handshake_mac_handle_sha, dataptr, datalen); _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 _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, void *i_data, uint32 i_datasize, gnutls_handshake_description_t type) { int ret; uint8 *data; uint32 datasize; int pos = 0; if (i_data == NULL && i_datasize == 0) { /* we are resuming a previously interrupted * send. */ ret = _gnutls_handshake_io_write_flush (session); return ret; } if (i_data == NULL && i_datasize > 0) { gnutls_assert (); return GNUTLS_E_INVALID_REQUEST; } /* first run */ datasize = i_datasize + HANDSHAKE_HEADER_SIZE; data = gnutls_alloca (datasize); if (data == NULL) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } data[pos++] = (uint8) type; _gnutls_write_uint24 (i_datasize, &data[pos]); pos += 3; if (i_datasize > 0) memcpy (&data[pos], i_data, i_datasize); _gnutls_handshake_log ("HSK[%x]: %s was send [%ld bytes]\n", session, _gnutls_handshake2str (type), datasize); /* Here we keep the handshake messages in order to hash them... */ if (type != GNUTLS_HANDSHAKE_HELLO_REQUEST) if ((ret = _gnutls_handshake_hash_add_sent (session, type, data, datasize)) < 0) { gnutls_assert (); gnutls_afree (data); return ret; } session->internals.last_handshake_out = type; ret = _gnutls_handshake_io_send_int (session, GNUTLS_HANDSHAKE, type, data, datasize); 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 _gnutls_recv_handshake_header (gnutls_session_t session, gnutls_handshake_description_t type, gnutls_handshake_description_t * recv_type) { int ret; uint32 length32 = 0; uint8 *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 = _gnutls_handshake_io_recv_int (session, GNUTLS_HANDSHAKE, type, dataptr, SSL2_HEADERS); if (ret < 0) { gnutls_assert (); return ret; } /* The case ret==0 is caught here. */ if (ret != SSL2_HEADERS) { 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 = _gnutls_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) { 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) { 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 = _gnutls_read_uint24 (&dataptr[1]); handshake_header_size = HANDSHAKE_HEADER_SIZE; _gnutls_handshake_log ("HSK[%x]: %s was received [%ld bytes]\n", session, _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]; _gnutls_handshake_log ("HSK[%x]: %s(v2) was received [%ld bytes]\n", session, _gnutls_handshake2str (*recv_type), length32 + handshake_header_size); if (*recv_type != GNUTLS_HANDSHAKE_CLIENT_HELLO) { /* it should be one or nothing */ 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) { gnutls_assert (); return GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET; } return length32; } #define _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 _gnutls_handshake_hash_add_recvd (gnutls_session_t session, gnutls_handshake_description_t recv_type, opaque * header, uint16 header_size, opaque * dataptr, uint32 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 = _gnutls_handshake_hash_pending (session)) < 0) { gnutls_assert (); return ret; } /* here we buffer the handshake messages - needed at Finished message */ if (recv_type != GNUTLS_HANDSHAKE_HELLO_REQUEST) { if ((ret = _gnutls_handshake_buffer_put (session, header, header_size)) < 0) { gnutls_assert (); return ret; } if (datalen > 0) { if ((ret = _gnutls_handshake_buffer_put (session, dataptr, datalen)) < 0) { 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 _gnutls_recv_hello(). */ int _gnutls_recv_handshake (gnutls_session_t session, uint8 ** data, int *datalen, gnutls_handshake_description_t type, Optional optional) { int ret; uint32 length32 = 0; opaque *dataptr = NULL; gnutls_handshake_description_t recv_type; ret = _gnutls_recv_handshake_header (session, type, &recv_type); if (ret < 0) { /* In SRP when expecting the server hello we may receive * an alert instead. Do as the draft demands. */ if (ret == GNUTLS_E_WARNING_ALERT_RECEIVED && gnutls_alert_get (session) == GNUTLS_A_MISSING_SRP_USERNAME && type == GNUTLS_HANDSHAKE_SERVER_HELLO) { gnutls_assert (); return GNUTLS_E_INT_HANDSHAKE_AGAIN; } 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 = gnutls_malloc (length32); else if (recv_type != GNUTLS_HANDSHAKE_SERVER_HELLO_DONE) { gnutls_assert (); return GNUTLS_E_UNEXPECTED_PACKET_LENGTH; } if (dataptr == NULL && length32 > 0) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } if (datalen != NULL) *datalen = length32; if (length32 > 0) { ret = _gnutls_handshake_io_recv_int (session, GNUTLS_HANDSHAKE, type, dataptr, length32); if (ret <= 0) { gnutls_assert (); gnutls_free (dataptr); return (ret == 0) ? GNUTLS_E_UNEXPECTED_PACKET_LENGTH : ret; } } if (data != NULL && length32 > 0) *data = dataptr; ret = _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) { gnutls_assert (); _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. */ _gnutls_handshake_header_buffer_clear (session); switch (recv_type) { case GNUTLS_HANDSHAKE_CLIENT_HELLO: case GNUTLS_HANDSHAKE_SERVER_HELLO: ret = _gnutls_recv_hello (session, dataptr, length32); /* dataptr is freed because the caller does not * need it */ 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: ret = length32; break; default: gnutls_assert (); gnutls_free (dataptr); if (data != NULL) *data = NULL; ret = GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET; } return ret; } /* This function checks if the given cipher suite is supported, and sets it * to the session; */ static int _gnutls_client_set_ciphersuite (gnutls_session_t session, opaque suite[2]) { uint8 z; cipher_suite_st *cipher_suites; int cipher_suite_num; int i, err; z = 1; cipher_suite_num = _gnutls_supported_ciphersuites (session, &cipher_suites); if (cipher_suite_num < 0) { 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; } } gnutls_free (cipher_suites); if (z != 0) { gnutls_assert (); return GNUTLS_E_UNKNOWN_CIPHER_SUITE; } memcpy (session->security_parameters.current_cipher_suite.suite, suite, 2); _gnutls_handshake_log ("HSK[%x]: Selected cipher suite: %s\n", session, _gnutls_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 (_gnutls_get_kx_cred (session, _gnutls_cipher_suite_get_kx_algo (&session-> security_parameters. current_cipher_suite), &err) == NULL && err != 0) { 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 (_gnutls_cipher_suite_get_kx_algo (&session->security_parameters. current_cipher_suite)); if (session->internals.auth_struct == NULL) { _gnutls_handshake_log ("HSK[%x]: Cannot find the appropriate handler for the KX algorithm\n", session); gnutls_assert (); return GNUTLS_E_INTERNAL_ERROR; } return 0; } /* This function sets the given comp method to the session. */ static int _gnutls_client_set_comp_method (gnutls_session_t session, opaque comp_method) { int comp_methods_num; uint8 *compression_methods; int i; comp_methods_num = _gnutls_supported_compression_methods (session, &compression_methods); if (comp_methods_num < 0) { 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; } } gnutls_free (compression_methods); if (comp_methods_num != 0) { gnutls_assert (); return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM; } session->internals.compression_method = _gnutls_compression_get_id (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 _gnutls_client_check_if_resuming (gnutls_session_t session, opaque * session_id, int session_id_len) { opaque buf[2 * TLS_MAX_SESSION_ID_SIZE + 1]; _gnutls_handshake_log ("HSK[%x]: SessionID length: %d\n", session, session_id_len); _gnutls_handshake_log ("HSK[%x]: SessionID: %s\n", session, _gnutls_bin2hex (session_id, session_id_len, 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 _gnutls_read_server_hello (gnutls_session_t session, opaque * data, int datalen) { uint8 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[%x]: 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; } else { _gnutls_set_current_version (session, version); } pos += 2; DECR_LEN (len, TLS_RANDOM_SIZE); _gnutls_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) { 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 (_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 = _gnutls_client_set_ciphersuite (session, &data[pos]); if (ret < 0) { gnutls_assert (); return ret; } pos += 2; /* move to compression */ DECR_LEN (len, 1); ret = _gnutls_client_set_comp_method (session, data[pos++]); if (ret < 0) { gnutls_assert (); return GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM; } /* Parse extensions. */ if (version >= GNUTLS_TLS1) { ret = _gnutls_parse_extensions (session, &data[pos], len); /* len is the rest of the parsed length */ if (ret < 0) { 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 _gnutls_copy_ciphersuites (gnutls_session_t session, opaque * ret_data, size_t ret_data_size) { int ret, i; cipher_suite_st *cipher_suites; uint16 cipher_num; int datalen, pos; ret = _gnutls_supported_ciphersuites_sorted (session, &cipher_suites); if (ret < 0) { gnutls_assert (); return ret; } /* Here we remove any ciphersuite that does not conform * the certificate requested, or to the * authentication requested (eg SRP). */ ret = _gnutls_remove_unwanted_ciphersuites (session, &cipher_suites, ret, -1); if (ret < 0) { gnutls_assert (); gnutls_free (cipher_suites); return ret; } /* If no cipher suites were enabled. */ if (ret == 0) { gnutls_assert (); gnutls_free (cipher_suites); return GNUTLS_E_INSUFFICIENT_CREDENTIALS; } cipher_num = ret; cipher_num *= sizeof (uint16); /* in order to get bytes */ datalen = pos = 0; datalen += sizeof (uint16) + cipher_num; if ((size_t) datalen > ret_data_size) { gnutls_assert (); return GNUTLS_E_INTERNAL_ERROR; } _gnutls_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; } 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 _gnutls_copy_comp_methods (gnutls_session_t session, opaque * ret_data, size_t ret_data_size) { int ret, i; uint8 *compression_methods, comp_num; int datalen, pos; ret = _gnutls_supported_compression_methods (session, &compression_methods); if (ret < 0) { gnutls_assert (); return ret; } comp_num = ret; datalen = pos = 0; datalen += comp_num + 1; if ((size_t) datalen > ret_data_size) { 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]; } gnutls_free (compression_methods); return datalen; } /* 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 /* This function sends the client hello handshake message. */ static int _gnutls_send_client_hello (gnutls_session_t session, int again) { opaque *data = NULL; int extdatalen; int pos = 0; int datalen = 0, ret = 0; opaque rnd[TLS_RANDOM_SIZE]; gnutls_protocol_t hver; opaque extdata[MAX_EXT_DATA_LENGTH]; opaque *SessionID = session->internals.resumed_security_parameters.session_id; uint8 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 = gnutls_malloc (datalen); if (data == NULL) { 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 = _gnutls_version_max (session); else { /* we are resuming a session */ hver = session->internals.resumed_security_parameters.version; } if (hver == GNUTLS_VERSION_UNKNOWN || hver == 0) { gnutls_assert (); gnutls_free (data); return GNUTLS_E_INTERNAL_ERROR; } data[pos++] = _gnutls_version_get_major (hver); data[pos++] = _gnutls_version_get_minor (hver); /* Set the version we advertized as maximum * (RSA uses it). */ _gnutls_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. */ _gnutls_set_current_version (session, hver); /* In order to know when this session was initiated. */ session->security_parameters.timestamp = time (NULL); /* Generate random data */ _gnutls_tls_create_random (rnd); _gnutls_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 = _gnutls_copy_ciphersuites (session, extdata, sizeof (extdata)); if (extdatalen > 0) { datalen += extdatalen; data = gnutls_realloc_fast (data, datalen); if (data == NULL) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } memcpy (&data[pos], extdata, extdatalen); pos += extdatalen; } else { if (extdatalen == 0) extdatalen = GNUTLS_E_INTERNAL_ERROR; gnutls_free (data); gnutls_assert (); return extdatalen; } /* Copy the compression methods. */ extdatalen = _gnutls_copy_comp_methods (session, extdata, sizeof (extdata)); if (extdatalen > 0) { datalen += extdatalen; data = gnutls_realloc_fast (data, datalen); if (data == NULL) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } memcpy (&data[pos], extdata, extdatalen); pos += extdatalen; } else { if (extdatalen == 0) extdatalen = GNUTLS_E_INTERNAL_ERROR; gnutls_free (data); gnutls_assert (); return extdatalen; } /* Generate and copy TLS extensions. */ if (hver >= GNUTLS_TLS1) { extdatalen = _gnutls_gen_extensions (session, extdata, sizeof (extdata)); if (extdatalen > 0) { datalen += extdatalen; data = gnutls_realloc_fast (data, datalen); if (data == NULL) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } memcpy (&data[pos], extdata, extdatalen); } else if (extdatalen < 0) { gnutls_assert (); gnutls_free (data); return extdatalen; } } } ret = _gnutls_send_handshake (session, data, datalen, GNUTLS_HANDSHAKE_CLIENT_HELLO); gnutls_free (data); return ret; } static int _gnutls_send_server_hello (gnutls_session_t session, int again) { opaque *data = NULL; opaque extdata[MAX_EXT_DATA_LENGTH]; int extdatalen; int pos = 0; int datalen, ret = 0; uint8 comp; opaque *SessionID = session->security_parameters.session_id; uint8 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; #ifdef ENABLE_SRP if (IS_SRP_KX (_gnutls_cipher_suite_get_kx_algo (&session->security_parameters.current_cipher_suite))) { /* While resuming we cannot check the username extension since it is * not available at this point. It will be copied on connection * state activation. */ if (session->internals.resumed == RESUME_FALSE && session->security_parameters.extensions.srp_username[0] == 0) { /* The peer didn't send a valid SRP extension with the * SRP username. The draft requires that we send an * alert and start the handshake again. */ gnutls_assert (); ret = gnutls_alert_send (session, GNUTLS_AL_WARNING, GNUTLS_A_MISSING_SRP_USERNAME); if (ret < 0) { gnutls_assert (); return ret; } return GNUTLS_E_INT_HANDSHAKE_AGAIN; } } #endif if (again == 0) { datalen = 2 + session_id_len + 1 + TLS_RANDOM_SIZE + 3; extdatalen = _gnutls_gen_extensions (session, extdata, sizeof (extdata)); if (extdatalen < 0) { gnutls_assert (); return extdatalen; } data = gnutls_alloca (datalen + extdatalen); if (data == NULL) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } data[pos++] = _gnutls_version_get_major (session->security_parameters.version); data[pos++] = _gnutls_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; _gnutls_handshake_log ("HSK[%x]: SessionID: %s\n", session, _gnutls_bin2hex (SessionID, session_id_len, buf, sizeof (buf))); memcpy (&data[pos], session->security_parameters.current_cipher_suite.suite, 2); pos += 2; comp = (uint8) _gnutls_compression_get_num (session-> internals.compression_method); data[pos++] = comp; if (extdatalen > 0) { datalen += extdatalen; memcpy (&data[pos], extdata, extdatalen); } } ret = _gnutls_send_handshake (session, data, datalen, GNUTLS_HANDSHAKE_SERVER_HELLO); gnutls_afree (data); return ret; } int _gnutls_send_hello (gnutls_session_t session, int again) { int ret; if (session->security_parameters.entity == GNUTLS_CLIENT) { ret = _gnutls_send_client_hello (session, again); } else { /* SERVER */ ret = _gnutls_send_server_hello (session, again); } return ret; } /* RECEIVE A HELLO MESSAGE. This should be called from gnutls_recv_handshake_int only if a * hello message is expected. It uses the security_parameters.current_cipher_suite * and internals.compression_method. */ int _gnutls_recv_hello (gnutls_session_t session, opaque * data, int datalen) { int ret; if (session->security_parameters.entity == GNUTLS_CLIENT) { ret = _gnutls_read_server_hello (session, data, datalen); if (ret < 0) { gnutls_assert (); return ret; } } else { /* Server side reading a client hello */ ret = _gnutls_read_client_hello (session, data, datalen); if (ret < 0) { gnutls_assert (); return ret; } } return ret; } /* 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 --------> * [ChangeCipherSpec] * <-------- Finished * * (*): means optional packet. */ /** * gnutls_rehandshake - This function will renegotiate security parameters * @session: is a #gnutls_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 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. * **/ 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; 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; } /* This function initialized the handshake hash session. * required for finished messages. */ inline static int _gnutls_handshake_hash_init (gnutls_session_t session) { if (session->internals.handshake_mac_handle_md5 == NULL) { session->internals.handshake_mac_handle_md5 = _gnutls_hash_init (GNUTLS_MAC_MD5); if (session->internals.handshake_mac_handle_md5 == GNUTLS_HASH_FAILED) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } } if (session->internals.handshake_mac_handle_sha == NULL) { session->internals.handshake_mac_handle_sha = _gnutls_hash_init (GNUTLS_MAC_SHA1); if (session->internals.handshake_mac_handle_sha == GNUTLS_HASH_FAILED) { gnutls_assert (); return GNUTLS_E_MEMORY_ERROR; } } return 0; } /** * gnutls_handshake - This is the main function in the handshake protocol. * @session: is a #gnutls_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. * gnutls_record_get_direction() and gnutls_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. * **/ int gnutls_handshake (gnutls_session_t session) { int ret; if ((ret = _gnutls_handshake_hash_init (session)) < 0) { gnutls_assert (); return ret; } if (session->security_parameters.entity == GNUTLS_CLIENT) { ret = _gnutls_handshake_client (session); } else { ret = _gnutls_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; } ret = _gnutls_handshake_common (session); if (ret < 0) { if (_gnutls_abort_handshake (session, ret) == 0) STATE = STATE0; return ret; } STATE = STATE0; _gnutls_handshake_io_buffer_clear (session); _gnutls_handshake_internal_state_clear (session); return 0; } /* Here if GNUTLS_E_INT_HANDSHAKE_AGAIN is received we go to * restart. This works because this error code may only be * received on the first 2 handshake packets. If for some reason * this changes we should return GNUTLS_E_AGAIN. */ #define IMED_RET( str, ret) do { \ if (ret < 0) { \ if (ret == GNUTLS_E_INT_HANDSHAKE_AGAIN && \ session->internals.handshake_restarted == 1) \ ret = GNUTLS_E_INTERNAL_ERROR; \ if (ret == GNUTLS_E_INT_HANDSHAKE_AGAIN) { \ STATE = STATE0; \ session->internals.handshake_restarted = 1; \ goto restart; \ } \ if (gnutls_error_is_fatal(ret)==0) return ret; \ gnutls_assert(); \ ERR( str, ret); \ _gnutls_handshake_hash_buffers_clear(session); \ return ret; \ } } while (0) /* * _gnutls_handshake_client * This function performs the client side of the handshake of the TLS/SSL protocol. */ int _gnutls_handshake_client (gnutls_session_t session) { int ret = 0; #ifdef HANDSHAKE_DEBUG char buf[64]; if (session->internals.resumed_security_parameters.session_id_size > 0) _gnutls_handshake_log ("HSK[%x]: Ask to resume: %s\n", session, _gnutls_bin2hex (session->internals. resumed_security_parameters. session_id, session->internals. resumed_security_parameters. session_id_size, buf, sizeof (buf))); #endif restart: switch (STATE) { case STATE0: case STATE1: ret = _gnutls_send_hello (session, AGAIN (STATE1)); STATE = STATE1; IMED_RET ("send hello", ret); case STATE2: /* receive the server hello */ ret = _gnutls_recv_handshake (session, NULL, NULL, GNUTLS_HANDSHAKE_SERVER_HELLO, MANDATORY_PACKET); STATE = STATE2; IMED_RET ("recv hello", ret); case STATE3: /* RECV CERTIFICATE */ if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */ ret = _gnutls_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 = _gnutls_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 = _gnutls_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 = _gnutls_recv_handshake (session, NULL, NULL, GNUTLS_HANDSHAKE_SERVER_HELLO_DONE, MANDATORY_PACKET); STATE = STATE6; IMED_RET ("recv server hello done", ret); case STATE7: /* 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 (STATE7)); STATE = STATE7; IMED_RET ("send client certificate", ret); case STATE8: if (session->internals.resumed == RESUME_FALSE) /* if we are not resuming */ ret = _gnutls_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 = _gnutls_send_client_certificate_verify (session, AGAIN (STATE9)); STATE = STATE9; IMED_RET ("send client certificate verify", ret); STATE = STATE0; default: break; } return 0; } /* This function sends the final handshake packets and initializes connection */ static int _gnutls_send_handshake_final (gnutls_session_t session, int init) { int ret = 0; /* Send the CHANGE CIPHER SPEC PACKET */ switch (STATE) { case STATE0: case STATE20: ret = _gnutls_send_change_cipher_spec (session, AGAIN (STATE20)); STATE = STATE20; if (ret < 0) { ERR ("send ChangeCipherSpec", ret); 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; } case STATE21: /* send the finished message */ ret = _gnutls_send_finished (session, AGAIN (STATE21)); STATE = STATE21; if (ret < 0) { ERR ("send Finished", ret); 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 _gnutls_recv_handshake_final (gnutls_session_t session, int init) { int ret = 0; uint8 ch; switch (STATE) { case STATE0: case STATE30: ret = _gnutls_recv_int (session, GNUTLS_CHANGE_CIPHER_SPEC, -1, &ch, 1); STATE = STATE30; if (ret <= 0) { ERR ("recv ChangeCipherSpec", ret); 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 = _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; } case STATE31: ret = _gnutls_recv_finished (session); STATE = STATE31; if (ret < 0) { ERR ("recv finished", ret); gnutls_assert (); return ret; } STATE = STATE0; default: break; } return 0; } /* * _gnutls_handshake_server * This function does the server stuff of the handshake protocol. */ int _gnutls_handshake_server (gnutls_session_t session) { int ret = 0; restart: switch (STATE) { case STATE0: case STATE1: ret = _gnutls_recv_handshake (session, NULL, NULL, GNUTLS_HANDSHAKE_CLIENT_HELLO, MANDATORY_PACKET); STATE = STATE1; IMED_RET ("recv hello", ret); case STATE2: ret = _gnutls_send_hello (session, AGAIN (STATE2)); STATE = STATE2; IMED_RET ("send hello", 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 = _gnutls_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 = _gnutls_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 = _gnutls_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 = _gnutls_send_empty_handshake (session, GNUTLS_HANDSHAKE_SERVER_HELLO_DONE, AGAIN (STATE6)); STATE = STATE6; IMED_RET ("send server hello done", 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 = _gnutls_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 = _gnutls_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 = _gnutls_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; } int _gnutls_handshake_common (gnutls_session_t session) { int ret = 0; restart: /* 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 = _gnutls_recv_handshake_final (session, TRUE); IMED_RET ("recv handshake final", ret); ret = _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 = _gnutls_send_handshake_final (session, TRUE); IMED_RET ("send handshake final 2", ret); ret = _gnutls_recv_handshake_final (session, FALSE); IMED_RET ("recv handshake final 2", ret); } if (session->security_parameters.entity == GNUTLS_SERVER) { /* in order to support session resuming */ _gnutls_server_register_current_session (session); } /* clear handshake buffer */ _gnutls_handshake_hash_buffers_clear (session); return ret; } int _gnutls_generate_session_id (opaque * session_id, uint8 * len) { *len = TLS_MAX_SESSION_ID_SIZE; if (gc_nonce (session_id, *len) != GC_OK) { gnutls_assert (); return GNUTLS_E_RANDOM_FAILED; } return 0; } int _gnutls_recv_hello_request (gnutls_session_t session, void *data, uint32 data_size) { uint8 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 *) data)[0]; if (type == GNUTLS_HANDSHAKE_HELLO_REQUEST) return GNUTLS_E_REHANDSHAKE; else { 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 (gnutls_session_t session, gnutls_kx_algorithm_t kx, gnutls_kx_algorithm_t * alg, int alg_size) { int cred_type; gnutls_dh_params_t dh_params = NULL; gnutls_rsa_params_t rsa_params = NULL; int j; cred_type = _gnutls_map_kx_get_cred (kx, 1); /* Read the Diffie Hellman parameters, if any. */ if (cred_type == GNUTLS_CRD_CERTIFICATE) { int delete; gnutls_certificate_credentials_t x509_cred = (gnutls_certificate_credentials_t) _gnutls_get_cred (session->key, cred_type, NULL); if (x509_cred != NULL) { dh_params = _gnutls_certificate_get_dh_params (x509_cred, session); rsa_params = _gnutls_certificate_get_rsa_params (x509_cred, 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; #ifdef ENABLE_ANON } else if (cred_type == GNUTLS_CRD_ANON) { gnutls_anon_server_credentials_t anon_cred = (gnutls_anon_server_credentials_t) _gnutls_get_cred (session->key, cred_type, NULL); if (anon_cred != NULL) { dh_params = _gnutls_anon_get_dh_params (anon_cred, session); } #endif } 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 (_gnutls_kx_needs_rsa_params (kx) != 0) { /* needs rsa params. */ if (_gnutls_get_rsa_params (rsa_params) == NULL) return 1; } if (_gnutls_kx_needs_dh_params (kx) != 0) { /* needs DH params. */ if (_gnutls_get_dh_params (dh_params) == NULL) 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 gnutls_supported_ciphersuites(), * by checking certificates etc. */ int _gnutls_remove_unwanted_ciphersuites (gnutls_session_t session, cipher_suite_st ** cipherSuites, int numCipherSuites, gnutls_pk_algorithm_t requested_pk_algo) { int ret = 0; cipher_suite_st *newSuite, cs; int newSuiteSize = 0, i; gnutls_certificate_credentials_t x509_cred; gnutls_kx_algorithm_t kx; int server = session->security_parameters.entity == GNUTLS_SERVER ? 1 : 0; gnutls_kx_algorithm_t *alg; int alg_size; /* 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). */ x509_cred = (gnutls_certificate_credentials_t) _gnutls_get_cred (session->key, GNUTLS_CRD_CERTIFICATE, NULL); /* if x509_cred==NULL we should remove all X509 ciphersuites */ if (session->security_parameters.entity == GNUTLS_SERVER && x509_cred != NULL) { ret = _gnutls_server_select_cert (session, requested_pk_algo); if (ret < 0) { gnutls_assert (); return ret; } } /* get all the key exchange algorithms that are * supported by the X509 certificate parameters. */ if ((ret = _gnutls_selected_cert_supported_kx (session, &alg, &alg_size)) < 0) { gnutls_assert (); return ret; } newSuite = gnutls_malloc (numCipherSuites * sizeof (cipher_suite_st)); if (newSuite == NULL) { gnutls_assert (); 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 = _gnutls_cipher_suite_get_kx_algo (&(*cipherSuites)[i]); /* if it is defined but had no credentials */ if (_gnutls_get_kx_cred (session, kx, NULL) == NULL) { delete = 1; } else { delete = 0; if (server) delete = check_server_params (session, kx, alg, alg_size); } memcpy (&cs.suite, &(*cipherSuites)[i].suite, 2); if (delete == 0) { _gnutls_handshake_log ("HSK[%x]: Keeping ciphersuite: %s\n", session, _gnutls_cipher_suite_get_name (&cs)); memcpy (newSuite[newSuiteSize].suite, (*cipherSuites)[i].suite, 2); newSuiteSize++; } else { _gnutls_handshake_log ("HSK[%x]: Removing ciphersuite: %s\n", session, _gnutls_cipher_suite_get_name (&cs)); } } gnutls_free (alg); gnutls_free (*cipherSuites); *cipherSuites = newSuite; ret = newSuiteSize; return ret; } /** * 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 gnutls_handshake_set_max_packet_length (gnutls_session_t session, int max) { session->internals.max_handshake_data_buffer_size = max; } void _gnutls_set_adv_version (gnutls_session_t session, gnutls_protocol_t ver) { set_adv_version (session, _gnutls_version_get_major (ver), _gnutls_version_get_minor (ver)); } gnutls_protocol_t _gnutls_get_adv_version (gnutls_session_t session) { return _gnutls_version_get (_gnutls_get_adv_version_major (session), _gnutls_get_adv_version_minor (session)); } /** * gnutls_handshake_get_last_in - Returns the last handshake message received. * @session: is a #gnutls_session_t structure. * * Returns the last handshake message received. 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.h for the available handshake descriptions. **/ gnutls_handshake_description_t gnutls_handshake_get_last_in (gnutls_session_t session) { return session->internals.last_handshake_in; } /** * gnutls_handshake_get_last_out - Returns the last handshake message sent. * @session: is a #gnutls_session_t structure. * * Returns the last handshake message sent. 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.h for the available handshake descriptions. * **/ gnutls_handshake_description_t gnutls_handshake_get_last_out (gnutls_session_t session) { return session->internals.last_handshake_out; }