/* * SSLv3/TLSv1 server-side functions * * Copyright (C) 2006-2012, Brainspark B.V. * * This file is part of PolarSSL (http://www.polarssl.org) * Lead Maintainer: Paul Bakker * * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "polarssl/config.h" #if defined(POLARSSL_SSL_SRV_C) #include "polarssl/debug.h" #include "polarssl/ssl.h" #include #include #include static int ssl_parse_servername_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret; size_t servername_list_size, hostname_len; const unsigned char *p; servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( servername_list_size + 2 != len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } p = buf + 2; while( servername_list_size > 0 ) { hostname_len = ( ( p[1] << 8 ) | p[2] ); if( hostname_len + 3 > servername_list_size ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( p[0] == TLS_EXT_SERVERNAME_HOSTNAME ) { ret = ssl->f_sni( ssl->p_sni, ssl, p + 3, hostname_len ); if( ret != 0 ) { ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_UNRECOGNIZED_NAME ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } servername_list_size -= hostname_len + 3; p += hostname_len + 3; } if( servername_list_size != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } static int ssl_parse_renegotiation_info( ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret; if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE ) { if( len != 1 || buf[0] != 0x0 ) { SSL_DEBUG_MSG( 1, ( "non-zero length renegotiated connection field" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; } else { if( len != 1 + ssl->verify_data_len || buf[0] != ssl->verify_data_len || memcmp( buf + 1, ssl->peer_verify_data, ssl->verify_data_len ) != 0 ) { SSL_DEBUG_MSG( 1, ( "non-matching renegotiated connection field" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } return( 0 ); } static int ssl_parse_signature_algorithms_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t sig_alg_list_size; const unsigned char *p; sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( sig_alg_list_size + 2 != len || sig_alg_list_size %2 != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } p = buf + 2; while( sig_alg_list_size > 0 ) { if( p[1] != SSL_SIG_RSA ) { sig_alg_list_size -= 2; p += 2; continue; } #if defined(POLARSSL_SHA4_C) if( p[0] == SSL_HASH_SHA512 ) { ssl->handshake->sig_alg = SSL_HASH_SHA512; break; } if( p[0] == SSL_HASH_SHA384 ) { ssl->handshake->sig_alg = SSL_HASH_SHA384; break; } #endif #if defined(POLARSSL_SHA2_C) if( p[0] == SSL_HASH_SHA256 ) { ssl->handshake->sig_alg = SSL_HASH_SHA256; break; } if( p[0] == SSL_HASH_SHA224 ) { ssl->handshake->sig_alg = SSL_HASH_SHA224; break; } #endif if( p[0] == SSL_HASH_SHA1 ) { ssl->handshake->sig_alg = SSL_HASH_SHA1; break; } if( p[0] == SSL_HASH_MD5 ) { ssl->handshake->sig_alg = SSL_HASH_MD5; break; } sig_alg_list_size -= 2; p += 2; } SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d", ssl->handshake->sig_alg ) ); return( 0 ); } static int ssl_parse_client_hello( ssl_context *ssl ) { int ret; unsigned int i, j; size_t n; unsigned int ciph_len, sess_len; unsigned int comp_len; unsigned int ext_len = 0; unsigned char *buf, *p, *ext; int renegotiation_info_seen = 0; int handshake_failure = 0; SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) ); if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE && ( ret = ssl_fetch_input( ssl, 5 ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_fetch_input", ret ); return( ret ); } buf = ssl->in_hdr; SSL_DEBUG_BUF( 4, "record header", buf, 5 ); SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d", buf[0] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d", ( buf[3] << 8 ) | buf[4] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, protocol ver: [%d:%d]", buf[1], buf[2] ) ); /* * SSLv3 Client Hello * * Record layer: * 0 . 0 message type * 1 . 2 protocol version * 3 . 4 message length */ if( buf[0] != SSL_MSG_HANDSHAKE || buf[1] != SSL_MAJOR_VERSION_3 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } n = ( buf[3] << 8 ) | buf[4]; if( n < 45 || n > 512 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE && ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_fetch_input", ret ); return( ret ); } buf = ssl->in_msg; if( !ssl->renegotiation ) n = ssl->in_left - 5; else n = ssl->in_msglen; ssl->handshake->update_checksum( ssl, buf, n ); /* * SSL layer: * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 protocol version * 6 . 9 UNIX time() * 10 . 37 random bytes * 38 . 38 session id length * 39 . 38+x session id * 39+x . 40+x ciphersuitelist length * 41+x . .. ciphersuitelist * .. . .. compression alg. * .. . .. extensions */ SSL_DEBUG_BUF( 4, "record contents", buf, n ); SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d", ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]", buf[4], buf[5] ) ); /* * Check the handshake type and protocol version */ if( buf[0] != SSL_HS_CLIENT_HELLO || buf[4] != SSL_MAJOR_VERSION_3 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->major_ver = SSL_MAJOR_VERSION_3; ssl->minor_ver = ( buf[5] <= SSL_MINOR_VERSION_3 ) ? buf[5] : SSL_MINOR_VERSION_3; if( ssl->minor_ver < ssl->min_minor_ver ) { SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->min_major_ver, ssl->min_minor_ver ) ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_PROTOCOL_VERSION ); return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION ); } ssl->max_major_ver = buf[4]; ssl->max_minor_ver = buf[5]; memcpy( ssl->handshake->randbytes, buf + 6, 32 ); /* * Check the handshake message length */ if( buf[1] != 0 || n != (unsigned int) 4 + ( ( buf[2] << 8 ) | buf[3] ) ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the session length */ sess_len = buf[38]; if( sess_len > 32 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->session_negotiate->length = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, buf + 39, ssl->session_negotiate->length ); /* * Check the ciphersuitelist length */ ciph_len = ( buf[39 + sess_len] << 8 ) | ( buf[40 + sess_len] ); if( ciph_len < 2 || ciph_len > 256 || ( ciph_len % 2 ) != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the compression algorithms length */ comp_len = buf[41 + sess_len + ciph_len]; if( comp_len < 1 || comp_len > 16 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the extension length */ if( n > 42 + sess_len + ciph_len + comp_len ) { ext_len = ( buf[42 + sess_len + ciph_len + comp_len] << 8 ) | ( buf[43 + sess_len + ciph_len + comp_len] ); if( ( ext_len > 0 && ext_len < 4 ) || n != 44 + sess_len + ciph_len + comp_len + ext_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); SSL_DEBUG_BUF( 3, "Ext", buf + 44 + sess_len + ciph_len + comp_len, ext_len); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } ssl->session_negotiate->compression = SSL_COMPRESS_NULL; #if defined(POLARSSL_ZLIB_SUPPORT) for( i = 0; i < comp_len; ++i ) { if( buf[42 + sess_len + ciph_len + i] == SSL_COMPRESS_DEFLATE ) { ssl->session_negotiate->compression = SSL_COMPRESS_DEFLATE; break; } } #endif SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 6, 32 ); SSL_DEBUG_BUF( 3, "client hello, session id", buf + 38, sess_len ); SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", buf + 41 + sess_len, ciph_len ); SSL_DEBUG_BUF( 3, "client hello, compression", buf + 42 + sess_len + ciph_len, comp_len ); /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 ) { if( p[0] == 0 && p[1] == SSL_EMPTY_RENEGOTIATION_INFO ) { SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) ); if( ssl->renegotiation == SSL_RENEGOTIATION ) { SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV during renegotiation" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; break; } } /* * Search for a matching ciphersuite */ for( i = 0; ssl->ciphersuites[i] != 0; i++ ) { for( j = 0, p = buf + 41 + sess_len; j < ciph_len; j += 2, p += 2 ) { if( p[0] == 0 && p[1] == ssl->ciphersuites[i] ) goto have_ciphersuite; } } SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) ); return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN ); have_ciphersuite: ssl->session_negotiate->ciphersuite = ssl->ciphersuites[i]; ssl_optimize_checksum( ssl, ssl->session_negotiate->ciphersuite ); ext = buf + 44 + sess_len + ciph_len + comp_len; while( ext_len ) { unsigned int ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) ); unsigned int ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) ); if( ext_size + 4 > ext_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } switch( ext_id ) { case TLS_EXT_SERVERNAME: SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) ); if( ssl->f_sni == NULL ) break; ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; case TLS_EXT_RENEGOTIATION_INFO: SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) ); renegotiation_info_seen = 1; ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; case TLS_EXT_SIG_ALG: SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) ); if( ssl->renegotiation == SSL_RENEGOTIATION ) break; ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; default: SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)", ext_id ) ); } ext_len -= 4 + ext_size; ext += 4 + ext_size; if( ext_len > 0 && ext_len < 4 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } /* * Renegotiation security checks */ if( ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) ); handshake_failure = 1; } else if( ssl->renegotiation == SSL_RENEGOTIATION && ssl->secure_renegotiation == SSL_SECURE_RENEGOTIATION && renegotiation_info_seen == 0 ) { SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) ); handshake_failure = 1; } else if( ssl->renegotiation == SSL_RENEGOTIATION && ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && ssl->allow_legacy_renegotiation == SSL_LEGACY_NO_RENEGOTIATION ) { SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) ); handshake_failure = 1; } else if( ssl->renegotiation == SSL_RENEGOTIATION && ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && renegotiation_info_seen == 1 ) { SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) ); handshake_failure = 1; } if( handshake_failure == 1 ) { if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->in_left = 0; ssl->state++; SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) ); return( 0 ); } static int ssl_write_server_hello( ssl_context *ssl ) { time_t t; int ret, n; size_t ext_len = 0; unsigned char *buf, *p; SSL_DEBUG_MSG( 2, ( "=> write server hello" ) ); /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 protocol version * 6 . 9 UNIX time() * 10 . 37 random bytes */ buf = ssl->out_msg; p = buf + 4; *p++ = (unsigned char) ssl->major_ver; *p++ = (unsigned char) ssl->minor_ver; SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]", buf[4], buf[5] ) ); t = time( NULL ); *p++ = (unsigned char)( t >> 24 ); *p++ = (unsigned char)( t >> 16 ); *p++ = (unsigned char)( t >> 8 ); *p++ = (unsigned char)( t ); SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) ); if( ( ret = ssl->f_rng( ssl->p_rng, p, 28 ) ) != 0 ) return( ret ); p += 28; memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 ); SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 ); /* * 38 . 38 session id length * 39 . 38+n session id * 39+n . 40+n chosen ciphersuite * 41+n . 41+n chosen compression alg. */ ssl->session_negotiate->length = n = 32; *p++ = (unsigned char) ssl->session_negotiate->length; if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE || ssl->f_get_cache == NULL || ssl->f_get_cache( ssl->p_get_cache, ssl->session_negotiate ) != 0 ) { /* * Not found, create a new session id */ ssl->handshake->resume = 0; ssl->state++; if( ( ret = ssl->f_rng( ssl->p_rng, ssl->session_negotiate->id, n ) ) != 0 ) return( ret ); } else { /* * Found a matching session, resuming it */ ssl->handshake->resume = 1; ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC; if( ( ret = ssl_derive_keys( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_derive_keys", ret ); return( ret ); } } memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->length ); p += ssl->session_negotiate->length; SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) ); SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n ); SSL_DEBUG_MSG( 3, ( "%s session has been resumed", ssl->handshake->resume ? "a" : "no" ) ); *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 ); *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite ); *p++ = (unsigned char)( ssl->session_negotiate->compression ); SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %d", ssl->session_negotiate->ciphersuite ) ); SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", ssl->session_negotiate->compression ) ); SSL_DEBUG_MSG( 3, ( "server hello, prepping for secure renegotiation extension" ) ); ext_len += 5 + ssl->verify_data_len * 2; SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d", ext_len ) ); *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( ext_len ) & 0xFF ); /* * Secure renegotiation */ SSL_DEBUG_MSG( 3, ( "client hello, secure renegotiation extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO ) & 0xFF ); *p++ = 0x00; *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF; *p++ = ssl->verify_data_len * 2 & 0xFF; memcpy( p, ssl->peer_verify_data, ssl->verify_data_len ); p += ssl->verify_data_len; memcpy( p, ssl->own_verify_data, ssl->verify_data_len ); p += ssl->verify_data_len; ssl->out_msglen = p - buf; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_HELLO; ret = ssl_write_record( ssl ); SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); return( ret ); } static int ssl_write_certificate_request( ssl_context *ssl ) { int ret; size_t n = 0, dn_size, total_dn_size; unsigned char *buf, *p; const x509_cert *crt; SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); ssl->state++; if( ssl->authmode == SSL_VERIFY_NONE ) { SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) ); return( 0 ); } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 4 cert type count * 5 .. m-1 cert types * m .. m+1 sig alg length (TLS 1.2 only) * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only) * n .. n+1 length of all DNs * n+2 .. n+3 length of DN 1 * n+4 .. ... Distinguished Name #1 * ... .. ... length of DN 2, etc. */ buf = ssl->out_msg; p = buf + 4; /* * At the moment, only RSA certificates are supported */ *p++ = 1; *p++ = SSL_CERT_TYPE_RSA_SIGN; /* * Add signature_algorithms for verify (TLS 1.2) * Only add current running algorithm that is already required for * requested ciphersuite. * * Length is always 2 */ if( ssl->max_minor_ver == SSL_MINOR_VERSION_3 ) { ssl->handshake->verify_sig_alg = SSL_HASH_SHA256; *p++ = 0; *p++ = 2; if( ssl->session_negotiate->ciphersuite == TLS_RSA_WITH_AES_256_GCM_SHA384 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 ) { ssl->handshake->verify_sig_alg = SSL_HASH_SHA384; } *p++ = ssl->handshake->verify_sig_alg; *p++ = SSL_SIG_RSA; n += 4; } p += 2; crt = ssl->ca_chain; total_dn_size = 2; while( crt != NULL ) { if( p - buf > 4096 ) break; dn_size = crt->subject_raw.len; *p++ = (unsigned char)( dn_size >> 8 ); *p++ = (unsigned char)( dn_size ); memcpy( p, crt->subject_raw.p, dn_size ); p += dn_size; SSL_DEBUG_BUF( 3, "requested DN", p, dn_size ); total_dn_size += dn_size; crt = crt->next; } ssl->out_msglen = p - buf; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_CERTIFICATE_REQUEST; ssl->out_msg[6 + n] = (unsigned char)( total_dn_size >> 8 ); ssl->out_msg[7 + n] = (unsigned char)( total_dn_size ); ret = ssl_write_record( ssl ); SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) ); return( ret ); } static int ssl_write_server_key_exchange( ssl_context *ssl ) { #if defined(POLARSSL_DHM_C) int ret; size_t n, rsa_key_len = 0; unsigned char hash[64]; int hash_id = 0; unsigned int hashlen = 0; #endif SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) ); if( ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_DES_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 && ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 ) { SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) ); ssl->state++; return( 0 ); } #if !defined(POLARSSL_DHM_C) SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) ); return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE ); #else if( ssl->rsa_key == NULL ) { SSL_DEBUG_MSG( 1, ( "got no private key" ) ); return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Ephemeral DH parameters: * * struct { * opaque dh_p<1..2^16-1>; * opaque dh_g<1..2^16-1>; * opaque dh_Ys<1..2^16-1>; * } ServerDHParams; */ if( ( ret = mpi_copy( &ssl->handshake->dhm_ctx.P, &ssl->dhm_P ) ) != 0 || ( ret = mpi_copy( &ssl->handshake->dhm_ctx.G, &ssl->dhm_G ) ) != 0 ) { SSL_DEBUG_RET( 1, "mpi_copy", ret ); return( ret ); } if( ( ret = dhm_make_params( &ssl->handshake->dhm_ctx, mpi_size( &ssl->handshake->dhm_ctx.P ), ssl->out_msg + 4, &n, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_make_params", ret ); return( ret ); } SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X ); SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P ); SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G ); SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX ); if( ssl->minor_ver != SSL_MINOR_VERSION_3 ) { md5_context md5; sha1_context sha1; /* * digitally-signed struct { * opaque md5_hash[16]; * opaque sha_hash[20]; * }; * * md5_hash * MD5(ClientHello.random + ServerHello.random * + ServerParams); * sha_hash * SHA(ClientHello.random + ServerHello.random * + ServerParams); */ md5_starts( &md5 ); md5_update( &md5, ssl->handshake->randbytes, 64 ); md5_update( &md5, ssl->out_msg + 4, n ); md5_finish( &md5, hash ); sha1_starts( &sha1 ); sha1_update( &sha1, ssl->handshake->randbytes, 64 ); sha1_update( &sha1, ssl->out_msg + 4, n ); sha1_finish( &sha1, hash + 16 ); hashlen = 36; hash_id = SIG_RSA_RAW; } else { /* * digitally-signed struct { * opaque client_random[32]; * opaque server_random[32]; * ServerDHParams params; * }; */ #if defined(POLARSSL_SHA4_C) if( ssl->handshake->sig_alg == SSL_HASH_SHA512 ) { sha4_context sha4; sha4_starts( &sha4, 0 ); sha4_update( &sha4, ssl->handshake->randbytes, 64 ); sha4_update( &sha4, ssl->out_msg + 4, n ); sha4_finish( &sha4, hash ); hashlen = 64; hash_id = SIG_RSA_SHA512; } else if( ssl->handshake->sig_alg == SSL_HASH_SHA384 ) { sha4_context sha4; sha4_starts( &sha4, 1 ); sha4_update( &sha4, ssl->handshake->randbytes, 64 ); sha4_update( &sha4, ssl->out_msg + 4, n ); sha4_finish( &sha4, hash ); hashlen = 48; hash_id = SIG_RSA_SHA384; } else #endif #if defined(POLARSSL_SHA2_C) if( ssl->handshake->sig_alg == SSL_HASH_SHA256 ) { sha2_context sha2; sha2_starts( &sha2, 0 ); sha2_update( &sha2, ssl->handshake->randbytes, 64 ); sha2_update( &sha2, ssl->out_msg + 4, n ); sha2_finish( &sha2, hash ); hashlen = 32; hash_id = SIG_RSA_SHA256; } else if( ssl->handshake->sig_alg == SSL_HASH_SHA224 ) { sha2_context sha2; sha2_starts( &sha2, 1 ); sha2_update( &sha2, ssl->handshake->randbytes, 64 ); sha2_update( &sha2, ssl->out_msg + 4, n ); sha2_finish( &sha2, hash ); hashlen = 24; hash_id = SIG_RSA_SHA224; } else #endif if( ssl->handshake->sig_alg == SSL_HASH_SHA1 ) { sha1_context sha1; sha1_starts( &sha1 ); sha1_update( &sha1, ssl->handshake->randbytes, 64 ); sha1_update( &sha1, ssl->out_msg + 4, n ); sha1_finish( &sha1, hash ); hashlen = 20; hash_id = SIG_RSA_SHA1; } else if( ssl->handshake->sig_alg == SSL_HASH_MD5 ) { md5_context md5; md5_starts( &md5 ); md5_update( &md5, ssl->handshake->randbytes, 64 ); md5_update( &md5, ssl->out_msg + 4, n ); md5_finish( &md5, hash ); hashlen = 16; hash_id = SIG_RSA_MD5; } } SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen ); if ( ssl->rsa_key ) rsa_key_len = ssl->rsa_key_len( ssl->rsa_key ); if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { ssl->out_msg[4 + n] = ssl->handshake->sig_alg; ssl->out_msg[5 + n] = SSL_SIG_RSA; n += 2; } ssl->out_msg[4 + n] = (unsigned char)( rsa_key_len >> 8 ); ssl->out_msg[5 + n] = (unsigned char)( rsa_key_len ); if ( ssl->rsa_key ) { ret = ssl->rsa_sign( ssl->rsa_key, ssl->f_rng, ssl->p_rng, RSA_PRIVATE, hash_id, hashlen, hash, ssl->out_msg + 6 + n ); } if( ret != 0 ) { SSL_DEBUG_RET( 1, "pkcs1_sign", ret ); return( ret ); } SSL_DEBUG_BUF( 3, "my RSA sig", ssl->out_msg + 6 + n, rsa_key_len ); ssl->out_msglen = 6 + n + rsa_key_len; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_KEY_EXCHANGE; ssl->state++; if( ( ret = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) ); return( 0 ); #endif } static int ssl_write_server_hello_done( ssl_context *ssl ) { int ret; SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) ); ssl->out_msglen = 4; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_HELLO_DONE; ssl->state++; if( ( ret = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) ); return( 0 ); } static int ssl_parse_client_key_exchange( ssl_context *ssl ) { int ret; size_t i, n = 0; SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) ); if( ( ret = ssl_read_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != SSL_MSG_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->in_msg[0] != SSL_HS_CLIENT_KEY_EXCHANGE ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_DES_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 || ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 ) { #if !defined(POLARSSL_DHM_C) SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) ); return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE ); #else /* * Receive G^Y mod P, premaster = (G^Y)^X mod P */ n = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; if( n < 1 || n > ssl->handshake->dhm_ctx.len || n + 6 != ssl->in_hslen ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = dhm_read_public( &ssl->handshake->dhm_ctx, ssl->in_msg + 6, n ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_read_public", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_DHM_RP ); } SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY ); ssl->handshake->pmslen = ssl->handshake->dhm_ctx.len; if( ( ret = dhm_calc_secret( &ssl->handshake->dhm_ctx, ssl->handshake->premaster, &ssl->handshake->pmslen ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_calc_secret", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_DHM_CS ); } SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K ); #endif } else { if( ssl->rsa_key == NULL ) { SSL_DEBUG_MSG( 1, ( "got no private key" ) ); return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Decrypt the premaster using own private RSA key */ i = 4; if( ssl->rsa_key ) n = ssl->rsa_key_len( ssl->rsa_key ); ssl->handshake->pmslen = 48; if( ssl->minor_ver != SSL_MINOR_VERSION_0 ) { i += 2; if( ssl->in_msg[4] != ( ( n >> 8 ) & 0xFF ) || ssl->in_msg[5] != ( ( n ) & 0xFF ) ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } } if( ssl->in_hslen != i + n ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->rsa_key ) { ret = ssl->rsa_decrypt( ssl->rsa_key, RSA_PRIVATE, &ssl->handshake->pmslen, ssl->in_msg + i, ssl->handshake->premaster, sizeof(ssl->handshake->premaster) ); } if( ret != 0 || ssl->handshake->pmslen != 48 || ssl->handshake->premaster[0] != ssl->max_major_ver || ssl->handshake->premaster[1] != ssl->max_minor_ver ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); /* * Protection against Bleichenbacher's attack: * invalid PKCS#1 v1.5 padding must not cause * the connection to end immediately; instead, * send a bad_record_mac later in the handshake. */ ssl->handshake->pmslen = 48; ret = ssl->f_rng( ssl->p_rng, ssl->handshake->premaster, ssl->handshake->pmslen ); if( ret != 0 ) return( ret ); } } if( ( ret = ssl_derive_keys( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_derive_keys", ret ); return( ret ); } ssl->state++; SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) ); return( 0 ); } static int ssl_parse_certificate_verify( ssl_context *ssl ) { int ret; size_t n = 0, n1, n2; unsigned char hash[48]; int hash_id; unsigned int hashlen; SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) ); if( ssl->session_negotiate->peer_cert == NULL ) { SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } ssl->handshake->calc_verify( ssl, hash ); if( ( ret = ssl_read_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_read_record", ret ); return( ret ); } ssl->state++; if( ssl->in_msgtype != SSL_MSG_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } if( ssl->in_msg[0] != SSL_HS_CERTIFICATE_VERIFY ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { /* * As server we know we either have SSL_HASH_SHA384 or * SSL_HASH_SHA256 */ if( ssl->in_msg[4] != ssl->handshake->verify_sig_alg || ssl->in_msg[5] != SSL_SIG_RSA ) { SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg for verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } if( ssl->handshake->verify_sig_alg == SSL_HASH_SHA384 ) { hashlen = 48; hash_id = SIG_RSA_SHA384; } else { hashlen = 32; hash_id = SIG_RSA_SHA256; } n += 2; } else { hashlen = 36; hash_id = SIG_RSA_RAW; } n1 = ssl->session_negotiate->peer_cert->rsa.len; n2 = ( ssl->in_msg[4 + n] << 8 ) | ssl->in_msg[5 + n]; if( n + n1 + 6 != ssl->in_hslen || n1 != n2 ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } ret = rsa_pkcs1_verify( &ssl->session_negotiate->peer_cert->rsa, RSA_PUBLIC, hash_id, hashlen, hash, ssl->in_msg + 6 + n ); if( ret != 0 ) { SSL_DEBUG_RET( 1, "rsa_pkcs1_verify", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) ); return( 0 ); } /* * SSL handshake -- server side */ int ssl_handshake_server( ssl_context *ssl ) { int ret = 0; SSL_DEBUG_MSG( 2, ( "=> handshake server" ) ); while( ssl->state != SSL_HANDSHAKE_OVER ) { SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) ); if( ( ret = ssl_flush_output( ssl ) ) != 0 ) break; switch( ssl->state ) { case SSL_HELLO_REQUEST: ssl->state = SSL_CLIENT_HELLO; break; /* * <== ClientHello */ case SSL_CLIENT_HELLO: ret = ssl_parse_client_hello( ssl ); break; /* * ==> ServerHello * Certificate * ( ServerKeyExchange ) * ( CertificateRequest ) * ServerHelloDone */ case SSL_SERVER_HELLO: ret = ssl_write_server_hello( ssl ); break; case SSL_SERVER_CERTIFICATE: ret = ssl_write_certificate( ssl ); break; case SSL_SERVER_KEY_EXCHANGE: ret = ssl_write_server_key_exchange( ssl ); break; case SSL_CERTIFICATE_REQUEST: ret = ssl_write_certificate_request( ssl ); break; case SSL_SERVER_HELLO_DONE: ret = ssl_write_server_hello_done( ssl ); break; /* * <== ( Certificate/Alert ) * ClientKeyExchange * ( CertificateVerify ) * ChangeCipherSpec * Finished */ case SSL_CLIENT_CERTIFICATE: ret = ssl_parse_certificate( ssl ); break; case SSL_CLIENT_KEY_EXCHANGE: ret = ssl_parse_client_key_exchange( ssl ); break; case SSL_CERTIFICATE_VERIFY: ret = ssl_parse_certificate_verify( ssl ); break; case SSL_CLIENT_CHANGE_CIPHER_SPEC: ret = ssl_parse_change_cipher_spec( ssl ); break; case SSL_CLIENT_FINISHED: ret = ssl_parse_finished( ssl ); break; /* * ==> ChangeCipherSpec * Finished */ case SSL_SERVER_CHANGE_CIPHER_SPEC: ret = ssl_write_change_cipher_spec( ssl ); break; case SSL_SERVER_FINISHED: ret = ssl_write_finished( ssl ); break; case SSL_FLUSH_BUFFERS: SSL_DEBUG_MSG( 2, ( "handshake: done" ) ); ssl->state = SSL_HANDSHAKE_WRAPUP; break; case SSL_HANDSHAKE_WRAPUP: ssl_handshake_wrapup( ssl ); break; default: SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) ); return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); } if( ret != 0 ) break; } SSL_DEBUG_MSG( 2, ( "<= handshake server" ) ); return( ret ); } #endif