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mbedtls/library/ssl_srv.c
Manuel Pégourié-Gonnard d6b721c7ee More ssl_parse_client_hello() adjustments
2014-10-21 16:30:08 +02:00

3415 lines
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/*
* SSLv3/TLSv1 server-side functions
*
* Copyright (C) 2006-2014, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* 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.
*/
#if !defined(POLARSSL_CONFIG_FILE)
#include "polarssl/config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif
#if defined(POLARSSL_SSL_SRV_C)
#include "polarssl/debug.h"
#include "polarssl/ssl.h"
#if defined(POLARSSL_ECP_C)
#include "polarssl/ecp.h"
#endif
#if defined(POLARSSL_PLATFORM_C)
#include "polarssl/platform.h"
#else
#define polarssl_malloc malloc
#define polarssl_free free
#endif
#include <stdlib.h>
#include <stdio.h>
#if defined(POLARSSL_HAVE_TIME)
#include <time.h>
#endif
#if defined(POLARSSL_SSL_SESSION_TICKETS)
/* Implementation that should never be optimized out by the compiler */
static void polarssl_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
/*
* Serialize a session in the following format:
* 0 . n-1 session structure, n = sizeof(ssl_session)
* n . n+2 peer_cert length = m (0 if no certificate)
* n+3 . n+2+m peer cert ASN.1
*
* Assumes ticket is NULL (always true on server side).
*/
static int ssl_save_session( const ssl_session *session,
unsigned char *buf, size_t buf_len,
size_t *olen )
{
unsigned char *p = buf;
size_t left = buf_len;
#if defined(POLARSSL_X509_CRT_PARSE_C)
size_t cert_len;
#endif /* POLARSSL_X509_CRT_PARSE_C */
if( left < sizeof( ssl_session ) )
return( -1 );
memcpy( p, session, sizeof( ssl_session ) );
p += sizeof( ssl_session );
left -= sizeof( ssl_session );
#if defined(POLARSSL_X509_CRT_PARSE_C)
if( session->peer_cert == NULL )
cert_len = 0;
else
cert_len = session->peer_cert->raw.len;
if( left < 3 + cert_len )
return( -1 );
*p++ = (unsigned char)( cert_len >> 16 & 0xFF );
*p++ = (unsigned char)( cert_len >> 8 & 0xFF );
*p++ = (unsigned char)( cert_len & 0xFF );
if( session->peer_cert != NULL )
memcpy( p, session->peer_cert->raw.p, cert_len );
p += cert_len;
#endif /* POLARSSL_X509_CRT_PARSE_C */
*olen = p - buf;
return( 0 );
}
/*
* Unserialise session, see ssl_save_session()
*/
static int ssl_load_session( ssl_session *session,
const unsigned char *buf, size_t len )
{
const unsigned char *p = buf;
const unsigned char * const end = buf + len;
#if defined(POLARSSL_X509_CRT_PARSE_C)
size_t cert_len;
#endif /* POLARSSL_X509_CRT_PARSE_C */
if( p + sizeof( ssl_session ) > end )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
memcpy( session, p, sizeof( ssl_session ) );
p += sizeof( ssl_session );
#if defined(POLARSSL_X509_CRT_PARSE_C)
if( p + 3 > end )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
cert_len = ( p[0] << 16 ) | ( p[1] << 8 ) | p[2];
p += 3;
if( cert_len == 0 )
{
session->peer_cert = NULL;
}
else
{
int ret;
if( p + cert_len > end )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
session->peer_cert = polarssl_malloc( sizeof( x509_crt ) );
if( session->peer_cert == NULL )
return( POLARSSL_ERR_SSL_MALLOC_FAILED );
x509_crt_init( session->peer_cert );
if( ( ret = x509_crt_parse_der( session->peer_cert,
p, cert_len ) ) != 0 )
{
x509_crt_free( session->peer_cert );
polarssl_free( session->peer_cert );
session->peer_cert = NULL;
return( ret );
}
p += cert_len;
}
#endif /* POLARSSL_X509_CRT_PARSE_C */
if( p != end )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
return( 0 );
}
/*
* Create session ticket, secured as recommended in RFC 5077 section 4:
*
* struct {
* opaque key_name[16];
* opaque iv[16];
* opaque encrypted_state<0..2^16-1>;
* opaque mac[32];
* } ticket;
*
* (the internal state structure differs, however).
*/
static int ssl_write_ticket( ssl_context *ssl, size_t *tlen )
{
int ret;
unsigned char * const start = ssl->out_msg + 10;
unsigned char *p = start;
unsigned char *state;
unsigned char iv[16];
size_t clear_len, enc_len, pad_len, i;
*tlen = 0;
if( ssl->ticket_keys == NULL )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
/* Write key name */
memcpy( p, ssl->ticket_keys->key_name, 16 );
p += 16;
/* Generate and write IV (with a copy for aes_crypt) */
if( ( ret = ssl->f_rng( ssl->p_rng, p, 16 ) ) != 0 )
return( ret );
memcpy( iv, p, 16 );
p += 16;
/*
* Dump session state
*
* After the session state itself, we still need room for 16 bytes of
* padding and 32 bytes of MAC, so there's only so much room left
*/
state = p + 2;
if( ssl_save_session( ssl->session_negotiate, state,
SSL_MAX_CONTENT_LEN - ( state - ssl->out_ctr ) - 48,
&clear_len ) != 0 )
{
return( POLARSSL_ERR_SSL_CERTIFICATE_TOO_LARGE );
}
SSL_DEBUG_BUF( 3, "session ticket cleartext", state, clear_len );
/* Apply PKCS padding */
pad_len = 16 - clear_len % 16;
enc_len = clear_len + pad_len;
for( i = clear_len; i < enc_len; i++ )
state[i] = (unsigned char) pad_len;
/* Encrypt */
if( ( ret = aes_crypt_cbc( &ssl->ticket_keys->enc, AES_ENCRYPT,
enc_len, iv, state, state ) ) != 0 )
{
return( ret );
}
/* Write length */
*p++ = (unsigned char)( ( enc_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( enc_len ) & 0xFF );
p = state + enc_len;
/* Compute and write MAC( key_name + iv + enc_state_len + enc_state ) */
sha256_hmac( ssl->ticket_keys->mac_key, 16, start, p - start, p, 0 );
p += 32;
*tlen = p - start;
SSL_DEBUG_BUF( 3, "session ticket structure", start, *tlen );
return( 0 );
}
/*
* Load session ticket (see ssl_write_ticket for structure)
*/
static int ssl_parse_ticket( ssl_context *ssl,
unsigned char *buf,
size_t len )
{
int ret;
ssl_session session;
unsigned char *key_name = buf;
unsigned char *iv = buf + 16;
unsigned char *enc_len_p = iv + 16;
unsigned char *ticket = enc_len_p + 2;
unsigned char *mac;
unsigned char computed_mac[32];
size_t enc_len, clear_len, i;
unsigned char pad_len, diff;
SSL_DEBUG_BUF( 3, "session ticket structure", buf, len );
if( len < 34 || ssl->ticket_keys == NULL )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
enc_len = ( enc_len_p[0] << 8 ) | enc_len_p[1];
mac = ticket + enc_len;
if( len != enc_len + 66 )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
/* Check name, in constant time though it's not a big secret */
diff = 0;
for( i = 0; i < 16; i++ )
diff |= key_name[i] ^ ssl->ticket_keys->key_name[i];
/* don't return yet, check the MAC anyway */
/* Check mac, with constant-time buffer comparison */
sha256_hmac( ssl->ticket_keys->mac_key, 16, buf, len - 32,
computed_mac, 0 );
for( i = 0; i < 32; i++ )
diff |= mac[i] ^ computed_mac[i];
/* Now return if ticket is not authentic, since we want to avoid
* decrypting arbitrary attacker-chosen data */
if( diff != 0 )
return( POLARSSL_ERR_SSL_INVALID_MAC );
/* Decrypt */
if( ( ret = aes_crypt_cbc( &ssl->ticket_keys->dec, AES_DECRYPT,
enc_len, iv, ticket, ticket ) ) != 0 )
{
return( ret );
}
/* Check PKCS padding */
pad_len = ticket[enc_len - 1];
ret = 0;
for( i = 2; i < pad_len; i++ )
if( ticket[enc_len - i] != pad_len )
ret = POLARSSL_ERR_SSL_BAD_INPUT_DATA;
if( ret != 0 )
return( ret );
clear_len = enc_len - pad_len;
SSL_DEBUG_BUF( 3, "session ticket cleartext", ticket, clear_len );
/* Actually load session */
if( ( ret = ssl_load_session( &session, ticket, clear_len ) ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "failed to parse ticket content" ) );
ssl_session_free( &session );
return( ret );
}
#if defined(POLARSSL_HAVE_TIME)
/* Check if still valid */
if( (int) ( time( NULL) - session.start ) > ssl->ticket_lifetime )
{
SSL_DEBUG_MSG( 1, ( "session ticket expired" ) );
ssl_session_free( &session );
return( POLARSSL_ERR_SSL_SESSION_TICKET_EXPIRED );
}
#endif
/*
* Keep the session ID sent by the client, since we MUST send it back to
* inform him we're accepting the ticket (RFC 5077 section 3.4)
*/
session.length = ssl->session_negotiate->length;
memcpy( &session.id, ssl->session_negotiate->id, session.length );
ssl_session_free( ssl->session_negotiate );
memcpy( ssl->session_negotiate, &session, sizeof( ssl_session ) );
/* Zeroize instead of free as we copied the content */
polarssl_zeroize( &session, sizeof( ssl_session ) );
return( 0 );
}
#endif /* POLARSSL_SSL_SESSION_TICKETS */
#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
/*
* Wrapper around f_sni, allowing use of ssl_set_own_cert() but
* making it act on ssl->handshake->sni_key_cert instead.
*/
static int ssl_sni_wrapper( ssl_context *ssl,
const unsigned char* name, size_t len )
{
int ret;
ssl_key_cert *key_cert_ori = ssl->key_cert;
ssl->key_cert = NULL;
ret = ssl->f_sni( ssl->p_sni, ssl, name, len );
ssl->handshake->sni_key_cert = ssl->key_cert;
ssl->key_cert = key_cert_ori;
return( ret );
}
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;
SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
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_sni_wrapper( ssl, p + 3, hostname_len );
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret );
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 );
}
#endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */
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
{
/* Check verify-data in constant-time. The length OTOH is no secret */
if( len != 1 + ssl->verify_data_len ||
buf[0] != ssl->verify_data_len ||
safer_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 );
}
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
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;
const unsigned char *end = buf + len;
const int *md_cur;
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 );
}
/*
* For now, ignore the SignatureAlgorithm part and rely on offered
* ciphersuites only for that part. To be fixed later.
*
* So, just look at the HashAlgorithm part.
*/
for( md_cur = md_list(); *md_cur != POLARSSL_MD_NONE; md_cur++ ) {
for( p = buf + 2; p < end; p += 2 ) {
if( *md_cur == (int) ssl_md_alg_from_hash( p[0] ) ) {
ssl->handshake->sig_alg = p[0];
goto have_sig_alg;
}
}
}
/* Some key echanges do not need signatures at all */
SSL_DEBUG_MSG( 3, ( "no signature_algorithm in common" ) );
return( 0 );
have_sig_alg:
SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
ssl->handshake->sig_alg ) );
return( 0 );
}
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
static int ssl_parse_supported_elliptic_curves( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t list_size, our_size;
const unsigned char *p;
const ecp_curve_info *curve_info, **curves;
list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( list_size + 2 != len ||
list_size % 2 != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Should never happen unless client duplicates the extension */
if( ssl->handshake->curves != NULL )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Don't allow our peer to make us allocate too much memory,
* and leave room for a final 0 */
our_size = list_size / 2 + 1;
if( our_size > POLARSSL_ECP_DP_MAX )
our_size = POLARSSL_ECP_DP_MAX;
if( ( curves = polarssl_malloc( our_size * sizeof( *curves ) ) ) == NULL )
return( POLARSSL_ERR_SSL_MALLOC_FAILED );
/* explicit void pointer cast for buggy MS compiler */
memset( (void *) curves, 0, our_size * sizeof( *curves ) );
ssl->handshake->curves = curves;
p = buf + 2;
while( list_size > 0 && our_size > 1 )
{
curve_info = ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
if( curve_info != NULL )
{
*curves++ = curve_info;
our_size--;
}
list_size -= 2;
p += 2;
}
return( 0 );
}
static int ssl_parse_supported_point_formats( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t list_size;
const unsigned char *p;
list_size = buf[0];
if( list_size + 1 != len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
p = buf + 2;
while( list_size > 0 )
{
if( p[0] == POLARSSL_ECP_PF_UNCOMPRESSED ||
p[0] == POLARSSL_ECP_PF_COMPRESSED )
{
ssl->handshake->ecdh_ctx.point_format = p[0];
SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
return( 0 );
}
list_size--;
p++;
}
return( 0 );
}
#endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
static int ssl_parse_max_fragment_length_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 1 || buf[0] >= SSL_MAX_FRAG_LEN_INVALID )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->session_negotiate->mfl_code = buf[0];
return( 0 );
}
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
ssl->session_negotiate->trunc_hmac = SSL_TRUNC_HMAC_ENABLED;
return( 0 );
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_SESSION_TICKETS)
static int ssl_parse_session_ticket_ext( ssl_context *ssl,
unsigned char *buf,
size_t len )
{
int ret;
if( ssl->session_tickets == SSL_SESSION_TICKETS_DISABLED )
return( 0 );
/* Remember the client asked us to send a new ticket */
ssl->handshake->new_session_ticket = 1;
SSL_DEBUG_MSG( 3, ( "ticket length: %d", len ) );
if( len == 0 )
return( 0 );
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
return( 0 );
}
/*
* Failures are ok: just ignore the ticket and proceed.
*/
if( ( ret = ssl_parse_ticket( ssl, buf, len ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_parse_ticket", ret );
return( 0 );
}
SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
ssl->handshake->resume = 1;
/* Don't send a new ticket after all, this one is OK */
ssl->handshake->new_session_ticket = 0;
return( 0 );
}
#endif /* POLARSSL_SSL_SESSION_TICKETS */
#if defined(POLARSSL_SSL_ALPN)
static int ssl_parse_alpn_ext( ssl_context *ssl,
const unsigned char *buf, size_t len )
{
size_t list_len, cur_len, ours_len;
const unsigned char *theirs, *start, *end;
const char **ours;
/* If ALPN not configured, just ignore the extension */
if( ssl->alpn_list == NULL )
return( 0 );
/*
* opaque ProtocolName<1..2^8-1>;
*
* struct {
* ProtocolName protocol_name_list<2..2^16-1>
* } ProtocolNameList;
*/
/* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
if( len < 4 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
list_len = ( buf[0] << 8 ) | buf[1];
if( list_len != len - 2 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
/*
* Use our order of preference
*/
start = buf + 2;
end = buf + len;
for( ours = ssl->alpn_list; *ours != NULL; ours++ )
{
ours_len = strlen( *ours );
for( theirs = start; theirs != end; theirs += cur_len )
{
/* If the list is well formed, we should get equality first */
if( theirs > end )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
cur_len = *theirs++;
/* Empty strings MUST NOT be included */
if( cur_len == 0 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
if( cur_len == ours_len &&
memcmp( theirs, *ours, cur_len ) == 0 )
{
ssl->alpn_chosen = *ours;
return( 0 );
}
}
}
/* If we get there, no match was found */
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif /* POLARSSL_SSL_ALPN */
/*
* Auxiliary functions for ServerHello parsing and related actions
*/
#if defined(POLARSSL_X509_CRT_PARSE_C)
/*
* Return 1 if the given EC key uses the given curve, 0 otherwise
*/
#if defined(POLARSSL_ECDSA_C)
static int ssl_key_matches_curves( pk_context *pk,
const ecp_curve_info **curves )
{
const ecp_curve_info **crv = curves;
ecp_group_id grp_id = pk_ec( *pk )->grp.id;
while( *crv != NULL )
{
if( (*crv)->grp_id == grp_id )
return( 1 );
crv++;
}
return( 0 );
}
#endif /* POLARSSL_ECDSA_C */
/*
* Try picking a certificate for this ciphersuite,
* return 0 on success and -1 on failure.
*/
static int ssl_pick_cert( ssl_context *ssl,
const ssl_ciphersuite_t * ciphersuite_info )
{
ssl_key_cert *cur, *list;
pk_type_t pk_alg = ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_key_cert != NULL )
list = ssl->handshake->sni_key_cert;
else
#endif
list = ssl->handshake->key_cert;
if( pk_alg == POLARSSL_PK_NONE )
return( 0 );
for( cur = list; cur != NULL; cur = cur->next )
{
if( ! pk_can_do( cur->key, pk_alg ) )
continue;
/*
* This avoids sending the client a cert it'll reject based on
* keyUsage or other extensions.
*
* It also allows the user to provision different certificates for
* different uses based on keyUsage, eg if they want to avoid signing
* and decrypting with the same RSA key.
*/
if( ssl_check_cert_usage( cur->cert, ciphersuite_info,
SSL_IS_SERVER ) != 0 )
{
continue;
}
#if defined(POLARSSL_ECDSA_C)
if( pk_alg == POLARSSL_PK_ECDSA )
{
if( ssl_key_matches_curves( cur->key, ssl->handshake->curves ) )
break;
}
else
#endif
break;
}
if( cur == NULL )
return( -1 );
ssl->handshake->key_cert = cur;
return( 0 );
}
#endif /* POLARSSL_X509_CRT_PARSE_C */
/*
* Check if a given ciphersuite is suitable for use with our config/keys/etc
* Sets ciphersuite_info only if the suite matches.
*/
static int ssl_ciphersuite_match( ssl_context *ssl, int suite_id,
const ssl_ciphersuite_t **ciphersuite_info )
{
const ssl_ciphersuite_t *suite_info;
suite_info = ssl_ciphersuite_from_id( suite_id );
if( suite_info == NULL )
{
SSL_DEBUG_MSG( 1, ( "ciphersuite info for %04x not found", suite_id ) );
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
}
if( suite_info->min_minor_ver > ssl->minor_ver ||
suite_info->max_minor_ver < ssl->minor_ver )
return( 0 );
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM &&
( suite_info->flags & POLARSSL_CIPHERSUITE_NODTLS ) )
return( 0 );
#endif
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
if( ssl_ciphersuite_uses_ec( suite_info ) &&
( ssl->handshake->curves == NULL ||
ssl->handshake->curves[0] == NULL ) )
return( 0 );
#endif
#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
/* If the ciphersuite requires a pre-shared key and we don't
* have one, skip it now rather than failing later */
if( ssl_ciphersuite_uses_psk( suite_info ) &&
ssl->f_psk == NULL &&
( ssl->psk == NULL || ssl->psk_identity == NULL ||
ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) )
return( 0 );
#endif
#if defined(POLARSSL_X509_CRT_PARSE_C)
/*
* Final check: if ciphersuite requires us to have a
* certificate/key of a particular type:
* - select the appropriate certificate if we have one, or
* - try the next ciphersuite if we don't
* This must be done last since we modify the key_cert list.
*/
if( ssl_pick_cert( ssl, suite_info ) != 0 )
return( 0 );
#endif
*ciphersuite_info = suite_info;
return( 0 );
}
#if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
static int ssl_parse_client_hello_v2( ssl_context *ssl )
{
int ret;
unsigned int i, j;
size_t n;
unsigned int ciph_len, sess_len, chal_len;
unsigned char *buf, *p;
const int *ciphersuites;
const ssl_ciphersuite_t *ciphersuite_info;
SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
buf = ssl->in_hdr;
SSL_DEBUG_BUF( 4, "record header", buf, 5 );
SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
buf[2] ) );
SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
buf[3], buf[4] ) );
/*
* SSLv2 Client Hello
*
* Record layer:
* 0 . 1 message length
*
* SSL layer:
* 2 . 2 message type
* 3 . 4 protocol version
*/
if( buf[2] != SSL_HS_CLIENT_HELLO ||
buf[3] != SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
if( n < 17 || n > 512 )
{
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[4] <= ssl->max_minor_ver )
? buf[4] : ssl->max_minor_ver;
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->handshake->max_major_ver = buf[3];
ssl->handshake->max_minor_ver = buf[4];
if( ( ret = ssl_fetch_input( ssl, 2 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
ssl->handshake->update_checksum( ssl, buf + 2, n );
buf = ssl->in_msg;
n = ssl->in_left - 5;
/*
* 0 . 1 ciphersuitelist length
* 2 . 3 session id length
* 4 . 5 challenge length
* 6 . .. ciphersuitelist
* .. . .. session id
* .. . .. challenge
*/
SSL_DEBUG_BUF( 4, "record contents", buf, n );
ciph_len = ( buf[0] << 8 ) | buf[1];
sess_len = ( buf[2] << 8 ) | buf[3];
chal_len = ( buf[4] << 8 ) | buf[5];
SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
ciph_len, sess_len, chal_len ) );
/*
* Make sure each parameter length is valid
*/
if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( sess_len > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( chal_len < 8 || chal_len > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( n != 6 + ciph_len + sess_len + chal_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + 6, ciph_len );
SSL_DEBUG_BUF( 3, "client hello, session id",
buf + 6 + ciph_len, sess_len );
SSL_DEBUG_BUF( 3, "client hello, challenge",
buf + 6 + ciph_len + sess_len, chal_len );
p = buf + 6 + ciph_len;
ssl->session_negotiate->length = sess_len;
memset( ssl->session_negotiate->id, 0,
sizeof( ssl->session_negotiate->id ) );
memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->length );
p += sess_len;
memset( ssl->handshake->randbytes, 0, 64 );
memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 && p[1] == 0 && p[2] == 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;
}
}
ciphersuites = ssl->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(POLARSSL_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
{
for( i = 0; ciphersuites[i] != 0; i++ )
#else
for( i = 0; ciphersuites[i] != 0; i++ )
{
for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
#endif
{
if( p[0] != 0 ||
p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
p[2] != ( ( ciphersuites[i] ) & 0xFF ) )
continue;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite_v2;
}
}
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
have_ciphersuite_v2:
ssl->session_negotiate->ciphersuite = ciphersuites[i];
ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
ssl_optimize_checksum( ssl, ssl->transform_negotiate->ciphersuite_info );
/*
* SSLv2 Client Hello relevant 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" ) );
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 v2" ) );
return( 0 );
}
#endif /* POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
static int ssl_parse_client_hello( ssl_context *ssl )
{
int ret;
unsigned int i, j;
unsigned int ciph_offset, comp_offset, ext_offset;
unsigned int msg_len, ciph_len, sess_len, comp_len, ext_len;
#if defined(POLARSSL_SSL_PROTO_DTLS)
unsigned int cookie_offset, cookie_len;
#endif
unsigned char *buf, *p, *ext;
int renegotiation_info_seen = 0;
int handshake_failure = 0;
const int *ciphersuites;
const ssl_ciphersuite_t *ciphersuite_info;
int major, minor;
SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
/*
* If renegotiating, then the input was read with ssl_read_record(),
* otherwise read it ourselves manually in order to support SSLv2
* ClientHello, which doesn't use the same record layer format.
*/
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
( ret = ssl_fetch_input( ssl, ssl_hdr_len( ssl ) ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
buf = ssl->in_hdr;
#if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
if( ssl->transport == SSL_TRANSPORT_STREAM && ( buf[0] & 0x80 ) != 0 )
return ssl_parse_client_hello_v2( ssl );
#endif
SSL_DEBUG_BUF( 4, "record header", buf, ssl_hdr_len( ssl ) );
/*
* SSLv3/TLS Client Hello
*
* Record layer:
* 0 . 0 message type
* 1 . 2 protocol version
* 3 . 4 message length
*/
SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
buf[0] ) );
if( buf[0] != SSL_MSG_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) );
SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]",
buf[1], buf[2] ) );
ssl_read_version( &major, &minor, ssl->transport, buf + 1 );
/* According to RFC 5246 Appendix E.1, the version here is typically
* "{03,00}, the lowest version number supported by the client, [or] the
* value of ClientHello.client_version", so the only meaningful check here
* is the major version shouldn't be less than 3 */
if( major < SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
{
if( msg_len > SSL_MAX_CONTENT_LEN )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( ( ret = ssl_fetch_input( ssl, ssl_hdr_len( ssl ) + msg_len ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
}
else
{
/* Set by ssl_read_record() */
msg_len = ssl->in_hslen;
}
buf = ssl->in_msg;
SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
ssl->handshake->update_checksum( ssl, buf, msg_len );
/*
* The DTLS handshake layer contains additional fields. Use them, then
* remove them so that it looks like TLS format to the rest of the code.
*/
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
{
/* 1 (type) + 3 (len) + 2 (seq) + 3 (frag_offset) + 3 (frag_len) */
if( msg_len < 12 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
// TODO: DTLS: check message_seq
/*
* For now we don't support fragmentation, so make sure
* fragment_offset == 0 and fragment_length == length
*
* TODO: DTLS: support fragmentation??
* Well, ClientHello is rarely much longer than 512 bytes
* so it will probably never be fragmented anyway...
*/
if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "handshake fragmentation not supported" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
}
/* Remove the additional fields */
memmove( buf + 4, buf + 12, msg_len - 12 );
msg_len -= 8;
}
#endif /* POLARSSL_SSL_PROTO_DTLS */
/*
* SSL layer:
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 protocol version
* 6 . 37 random bytes (starting with 4 bytes of Unix time)
* 38 . 38 session id length (1 byte)
* 39 . 38+x session id
* 39+x . 39+x DTLS only: cookie length (1 byte)
* 40+x . .. DTSL only: cookie
* .. . .. ciphersuite list length (2 bytes)
* .. . .. ciphersuite list
* .. . .. compression alg. list length (1 byte)
* .. . .. compression alg. list
* .. . .. extensions length (2 bytes, optional)
* .. . .. extensions (optional)
*
* Minimal length (with everything empty and extensions ommitted) is
* 4 + 2 + 32 + 1 + 2 + 1 = 42 bytes. Check that first, so that we can
* read at least up to session id length without worrying.
*/
/*
* Check the handshake type and message length
*/
if( msg_len < 42 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
if( buf[0] != SSL_HS_CLIENT_HELLO )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
if( buf[1] != 0 ||
msg_len != (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 and save the protocol version
*/
SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]",
buf[4], buf[5] ) );
ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
ssl->transport, buf + 4 );
ssl->handshake->max_major_ver = ssl->major_ver;
ssl->handshake->max_minor_ver = ssl->minor_ver;
if( ssl->major_ver < ssl->min_major_ver ||
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 );
}
if( ssl->major_ver > ssl->max_major_ver )
{
ssl->major_ver = ssl->max_major_ver;
ssl->minor_ver = ssl->max_minor_ver;
}
else if( ssl->minor_ver > ssl->max_minor_ver )
ssl->minor_ver = ssl->max_minor_ver;
/*
* Save client random (inc. Unix time)
*/
SSL_DEBUG_BUF( 3, "client hello, random bytes",
buf + 6, 32 );
memcpy( ssl->handshake->randbytes, buf + 6, 32 );
/*
* Check the session ID length and save session ID
*/
sess_len = buf[38];
if( sess_len > sizeof( ssl->session_negotiate->id ) ||
sess_len + 38 + 2 > msg_len ) /* 2 for cipherlist length field */
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, session id",
buf + 39, sess_len );
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 cookie length and content
*/
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
{
cookie_offset = 39 + sess_len;
cookie_len = buf[cookie_offset];
if( // cookie_len > <MAX> || // TODO-DTLS
cookie_offset + 1 + cookie_len + 2 > msg_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, cookie",
buf + cookie_offset + 1, cookie_len );
// TODO-DTLS: check cookie, reject if invalid!
}
#endif
/*
* Check the ciphersuitelist length (will be parsed later)
*/
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
ciph_offset = cookie_offset + 1 + cookie_len;
else
#endif
ciph_offset = 39 + sess_len;
ciph_len = ( buf[ciph_offset + 0] << 8 )
| ( buf[ciph_offset + 1] );
if( ciph_len < 2 ||
ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
( ciph_len % 2 ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + ciph_offset + 2, ciph_len );
/*
* Check the compression algorithms length and pick one
*/
comp_offset = ciph_offset + 2 + ciph_len;
comp_len = buf[comp_offset];
if( comp_len < 1 ||
comp_len > 16 ||
comp_len + comp_offset + 1 > msg_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, compression",
buf + comp_offset + 1, comp_len );
ssl->session_negotiate->compression = SSL_COMPRESS_NULL;
#if defined(POLARSSL_ZLIB_SUPPORT)
for( i = 0; i < comp_len; ++i )
{
if( buf[comp_offset + 1 + i] == SSL_COMPRESS_DEFLATE )
{
ssl->session_negotiate->compression = SSL_COMPRESS_DEFLATE;
break;
}
}
#endif
/*
* Check the extension length
*/
ext_offset = comp_offset + 1 + comp_len;
if( msg_len > ext_offset )
{
if( msg_len < ext_offset + 2 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ext_len = ( buf[ext_offset + 0] << 8 )
| ( buf[ext_offset + 1] );
if( ( ext_len > 0 && ext_len < 4 ) ||
msg_len != ext_offset + 2 + ext_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
SSL_DEBUG_BUF( 3, "client hello extensions",
buf + ext_offset + 2, ext_len );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
else
ext_len = 0;
ext = buf + ext_offset + 2;
while( ext_len != 0 )
{
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 )
{
#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
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;
#endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */
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;
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
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;
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
case TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
case TLS_EXT_SUPPORTED_POINT_FORMATS:
SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
ssl->handshake->cli_exts |= TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
case TLS_EXT_MAX_FRAGMENT_LENGTH:
SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
case TLS_EXT_TRUNCATED_HMAC:
SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_SESSION_TICKETS)
case TLS_EXT_SESSION_TICKET:
SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_SESSION_TICKETS */
#if defined(POLARSSL_SSL_ALPN)
case TLS_EXT_ALPN:
SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_SESSION_TICKETS */
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 );
}
}
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + ciph_offset + 2; 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;
}
}
/*
* 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 );
}
/*
* Search for a matching ciphersuite
* (At the end because we need information from the EC-based extensions
* and certificate from the SNI callback triggered by the SNI extension.)
*/
ciphersuites = ssl->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(POLARSSL_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
{
for( i = 0; ciphersuites[i] != 0; i++ )
#else
for( i = 0; ciphersuites[i] != 0; i++ )
{
for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
#endif
{
if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
continue;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite;
}
}
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
have_ciphersuite:
ssl->session_negotiate->ciphersuite = ciphersuites[i];
ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
ssl_optimize_checksum( ssl, ssl->transform_negotiate->ciphersuite_info );
ssl->in_left = 0;
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
return( 0 );
}
#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->session_negotiate->trunc_hmac == SSL_TRUNC_HMAC_DISABLED )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_SESSION_TICKETS)
static void ssl_write_session_ticket_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->handshake->new_session_ticket == 0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_SESSION_TICKETS */
static void ssl_write_renegotiation_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->secure_renegotiation != SSL_SECURE_RENEGOTIATION )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server 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;
*olen = 5 + ssl->verify_data_len * 2;
}
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
static void ssl_write_max_fragment_length_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->session_negotiate->mfl_code == SSL_MAX_FRAG_LEN_NONE )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
*p++ = 0x00;
*p++ = 1;
*p++ = ssl->session_negotiate->mfl_code;
*olen = 5;
}
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
static void ssl_write_supported_point_formats_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
((void) ssl);
if( ( ssl->handshake->cli_exts &
TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
*p++ = 0x00;
*p++ = 2;
*p++ = 1;
*p++ = POLARSSL_ECP_PF_UNCOMPRESSED;
*olen = 6;
}
#endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
#if defined(POLARSSL_SSL_ALPN )
static void ssl_write_alpn_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
if( ssl->alpn_chosen == NULL )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
/*
* 0 . 1 ext identifier
* 2 . 3 ext length
* 4 . 5 protocol list length
* 6 . 6 protocol name length
* 7 . 7+n protocol name
*/
buf[0] = (unsigned char)( ( TLS_EXT_ALPN >> 8 ) & 0xFF );
buf[1] = (unsigned char)( ( TLS_EXT_ALPN ) & 0xFF );
*olen = 7 + strlen( ssl->alpn_chosen );
buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF );
memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
}
#endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
static int ssl_write_server_hello( ssl_context *ssl )
{
#if defined(POLARSSL_HAVE_TIME)
time_t t;
#endif
int ret;
size_t olen, ext_len = 0, n;
unsigned char *buf, *p;
SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
if( ssl->f_rng == NULL )
{
SSL_DEBUG_MSG( 1, ( "no RNG provided") );
return( POLARSSL_ERR_SSL_NO_RNG );
}
/*
* 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;
ssl_write_version( ssl->major_ver, ssl->minor_ver,
ssl->transport, p );
p += 2;
SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
buf[4], buf[5] ) );
#if defined(POLARSSL_HAVE_TIME)
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 ) );
#else
if( ( ret = ssl->f_rng( ssl->p_rng, p, 4 ) ) != 0 )
return( ret );
p += 4;
#endif /* POLARSSL_HAVE_TIME */
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 );
/*
* Resume is 0 by default, see ssl_handshake_init().
* It may be already set to 1 by ssl_parse_session_ticket_ext().
* If not, try looking up session ID in our cache.
*/
if( ssl->handshake->resume == 0 &&
ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
ssl->session_negotiate->length != 0 &&
ssl->f_get_cache != NULL &&
ssl->f_get_cache( ssl->p_get_cache, ssl->session_negotiate ) == 0 )
{
SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
ssl->handshake->resume = 1;
}
if( ssl->handshake->resume == 0 )
{
/*
* New session, create a new session id,
* unless we're about to issue a session ticket
*/
ssl->state++;
#if defined(POLARSSL_HAVE_TIME)
ssl->session_negotiate->start = time( NULL );
#endif
#if defined(POLARSSL_SSL_SESSION_TICKETS)
if( ssl->handshake->new_session_ticket != 0 )
{
ssl->session_negotiate->length = n = 0;
memset( ssl->session_negotiate->id, 0, 32 );
}
else
#endif /* POLARSSL_SSL_SESSION_TICKETS */
{
ssl->session_negotiate->length = n = 32;
if( ( ret = ssl->f_rng( ssl->p_rng, ssl->session_negotiate->id,
n ) ) != 0 )
return( ret );
}
}
else
{
/*
* Resuming a session
*/
n = ssl->session_negotiate->length;
ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC;
if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
return( ret );
}
}
/*
* 38 . 38 session id length
* 39 . 38+n session id
* 39+n . 40+n chosen ciphersuite
* 41+n . 41+n chosen compression alg.
* 42+n . 43+n extensions length
* 44+n . 43+n+m extensions
*/
*p++ = (unsigned char) ssl->session_negotiate->length;
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: %s",
ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
ssl->session_negotiate->compression ) );
/*
* First write extensions, then the total length
*/
ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ALPN)
ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d", ext_len ) );
if( ext_len > 0 )
{
*p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ext_len ) & 0xFF );
p += ext_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 );
}
#if !defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
static int ssl_write_certificate_request( ssl_context *ssl )
{
const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
{
SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
ssl->state++;
return( 0 );
}
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
#else
static int ssl_write_certificate_request( ssl_context *ssl )
{
int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
size_t dn_size, total_dn_size; /* excluding length bytes */
size_t ct_len, sa_len; /* including length bytes */
unsigned char *buf, *p;
const x509_crt *crt;
SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
ssl->state++;
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ||
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;
/*
* Supported certificate types
*
* ClientCertificateType certificate_types<1..2^8-1>;
* enum { (255) } ClientCertificateType;
*/
ct_len = 0;
#if defined(POLARSSL_RSA_C)
p[1 + ct_len++] = SSL_CERT_TYPE_RSA_SIGN;
#endif
#if defined(POLARSSL_ECDSA_C)
p[1 + ct_len++] = SSL_CERT_TYPE_ECDSA_SIGN;
#endif
p[0] = (unsigned char) ct_len++;
p += ct_len;
sa_len = 0;
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
/*
* Add signature_algorithms for verify (TLS 1.2)
*
* SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* enum { (255) } HashAlgorithm;
* enum { (255) } SignatureAlgorithm;
*/
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
/*
* Only use current running hash algorithm that is already required
* for requested ciphersuite.
*/
ssl->handshake->verify_sig_alg = SSL_HASH_SHA256;
if( ssl->transform_negotiate->ciphersuite_info->mac ==
POLARSSL_MD_SHA384 )
{
ssl->handshake->verify_sig_alg = SSL_HASH_SHA384;
}
/*
* Supported signature algorithms
*/
#if defined(POLARSSL_RSA_C)
p[2 + sa_len++] = ssl->handshake->verify_sig_alg;
p[2 + sa_len++] = SSL_SIG_RSA;
#endif
#if defined(POLARSSL_ECDSA_C)
p[2 + sa_len++] = ssl->handshake->verify_sig_alg;
p[2 + sa_len++] = SSL_SIG_ECDSA;
#endif
p[0] = (unsigned char)( sa_len >> 8 );
p[1] = (unsigned char)( sa_len );
sa_len += 2;
p += sa_len;
}
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
/*
* DistinguishedName certificate_authorities<0..2^16-1>;
* opaque DistinguishedName<1..2^16-1>;
*/
p += 2;
crt = ssl->ca_chain;
total_dn_size = 0;
while( crt != NULL && crt->version != 0 )
{
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 += 2 + 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[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 );
ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size );
ret = ssl_write_record( ssl );
SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
return( ret );
}
#endif /* !POLARSSL_KEY_EXCHANGE_RSA_ENABLED &&
!POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED &&
!POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
!POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
static int ssl_get_ecdh_params_from_cert( ssl_context *ssl )
{
int ret;
if( ! pk_can_do( ssl_own_key( ssl ), POLARSSL_PK_ECKEY ) )
{
SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
return( POLARSSL_ERR_SSL_PK_TYPE_MISMATCH );
}
if( ( ret = ecdh_get_params( &ssl->handshake->ecdh_ctx,
pk_ec( *ssl_own_key( ssl ) ),
POLARSSL_ECDH_OURS ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ecdh_get_params" ), ret );
return( ret );
}
return( 0 );
}
#endif /* POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
static int ssl_write_server_key_exchange( ssl_context *ssl )
{
int ret;
size_t n = 0;
const ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
#if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
unsigned char *p = ssl->out_msg + 4;
unsigned char *dig_signed = p;
size_t dig_signed_len = 0, len;
((void) dig_signed);
((void) dig_signed_len);
#endif
SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
#if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK )
{
SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
ssl->state++;
return( 0 );
}
#endif
#if defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_ECDSA )
{
ssl_get_ecdh_params_from_cert( ssl );
SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
ssl->state++;
return( 0 );
}
#endif
#if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
{
/* TODO: Support identity hints */
*(p++) = 0x00;
*(p++) = 0x00;
n += 2;
}
#endif /* POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED ||
POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
{
/*
* 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,
(int) mpi_size( &ssl->handshake->dhm_ctx.P ),
p, &len, ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_make_params", ret );
return( ret );
}
dig_signed = p;
dig_signed_len = len;
p += len;
n += len;
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 );
}
#endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE__SOME__ECDHE_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
{
/*
* Ephemeral ECDH parameters:
*
* struct {
* ECParameters curve_params;
* ECPoint public;
* } ServerECDHParams;
*/
const ecp_curve_info **curve = NULL;
#if defined(POLARSSL_SSL_SET_CURVES)
const ecp_group_id *gid;
/* Match our preference list against the offered curves */
for( gid = ssl->curve_list; *gid != POLARSSL_ECP_DP_NONE; gid++ )
for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
if( (*curve)->grp_id == *gid )
goto curve_matching_done;
curve_matching_done:
#else
curve = ssl->handshake->curves;
#endif
if( *curve == NULL )
{
SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
}
SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
if( ( ret = ecp_use_known_dp( &ssl->handshake->ecdh_ctx.grp,
(*curve)->grp_id ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ecp_use_known_dp", ret );
return( ret );
}
if( ( ret = ecdh_make_params( &ssl->handshake->ecdh_ctx, &len,
p, SSL_MAX_CONTENT_LEN - n,
ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ecdh_make_params", ret );
return( ret );
}
dig_signed = p;
dig_signed_len = len;
p += len;
n += len;
SSL_DEBUG_ECP( 3, "ECDH: Q ", &ssl->handshake->ecdh_ctx.Q );
}
#endif /* POLARSSL_KEY_EXCHANGE__SOME__ECDHE_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA )
{
size_t signature_len = 0;
unsigned int hashlen = 0;
unsigned char hash[64];
md_type_t md_alg = POLARSSL_MD_NONE;
/*
* Choose hash algorithm. NONE means MD5 + SHA1 here.
*/
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
md_alg = ssl_md_alg_from_hash( ssl->handshake->sig_alg );
if( md_alg == POLARSSL_MD_NONE )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
}
else
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
defined(POLARSSL_SSL_PROTO_TLS1_1)
if( ciphersuite_info->key_exchange ==
POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA )
{
md_alg = POLARSSL_MD_SHA1;
}
else
#endif
{
md_alg = POLARSSL_MD_NONE;
}
/*
* Compute the hash to be signed
*/
#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
defined(POLARSSL_SSL_PROTO_TLS1_1)
if( md_alg == POLARSSL_MD_NONE )
{
md5_context md5;
sha1_context sha1;
md5_init( &md5 );
sha1_init( &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, dig_signed, dig_signed_len );
md5_finish( &md5, hash );
sha1_starts( &sha1 );
sha1_update( &sha1, ssl->handshake->randbytes, 64 );
sha1_update( &sha1, dig_signed, dig_signed_len );
sha1_finish( &sha1, hash + 16 );
hashlen = 36;
md5_free( &md5 );
sha1_free( &sha1 );
}
else
#endif /* POLARSSL_SSL_PROTO_SSL3 || POLARSSL_SSL_PROTO_TLS1 || \
POLARSSL_SSL_PROTO_TLS1_1 */
#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
defined(POLARSSL_SSL_PROTO_TLS1_2)
if( md_alg != POLARSSL_MD_NONE )
{
md_context_t ctx;
const md_info_t *md_info = md_info_from_type( md_alg );
md_init( &ctx );
/* Info from md_alg will be used instead */
hashlen = 0;
/*
* digitally-signed struct {
* opaque client_random[32];
* opaque server_random[32];
* ServerDHParams params;
* };
*/
if( ( ret = md_init_ctx( &ctx, md_info ) ) != 0 )
{
SSL_DEBUG_RET( 1, "md_init_ctx", ret );
return( ret );
}
md_starts( &ctx );
md_update( &ctx, ssl->handshake->randbytes, 64 );
md_update( &ctx, dig_signed, dig_signed_len );
md_finish( &ctx, hash );
md_free( &ctx );
}
else
#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 || \
POLARSSL_SSL_PROTO_TLS1_2 */
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen != 0 ? hashlen :
(unsigned int) ( md_info_from_type( md_alg ) )->size );
/*
* Make the signature
*/
if( ssl_own_key( ssl ) == NULL )
{
SSL_DEBUG_MSG( 1, ( "got no private key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
*(p++) = ssl->handshake->sig_alg;
*(p++) = ssl_sig_from_pk( ssl_own_key( ssl ) );
n += 2;
}
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
if( ( ret = pk_sign( ssl_own_key( ssl ), md_alg, hash, hashlen,
p + 2 , &signature_len,
ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "pk_sign", ret );
return( ret );
}
*(p++) = (unsigned char)( signature_len >> 8 );
*(p++) = (unsigned char)( signature_len );
n += 2;
SSL_DEBUG_BUF( 3, "my signature", p, signature_len );
p += signature_len;
n += signature_len;
}
#endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) ||
POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
ssl->out_msglen = 4 + n;
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 );
}
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 );
}
#if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
static int ssl_parse_client_dh_public( ssl_context *ssl, unsigned char **p,
const unsigned char *end )
{
int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
size_t n;
/*
* Receive G^Y mod P, premaster = (G^Y)^X mod P
*/
if( *p + 2 > end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
n = ( (*p)[0] << 8 ) | (*p)[1];
*p += 2;
if( *p + n > end )
{
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, *p, n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_read_public", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
*p += n;
SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
return( ret );
}
#endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)
static int ssl_parse_encrypted_pms( ssl_context *ssl,
const unsigned char *p,
const unsigned char *end,
size_t pms_offset )
{
int ret;
size_t len = pk_get_len( ssl_own_key( ssl ) );
unsigned char *pms = ssl->handshake->premaster + pms_offset;
unsigned char ver[2];
if( ! pk_can_do( ssl_own_key( ssl ), POLARSSL_PK_RSA ) )
{
SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* Decrypt the premaster using own private RSA key
*/
#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
defined(POLARSSL_SSL_PROTO_TLS1_2)
if( ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
*p++ != ( ( len ) & 0xFF ) )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
}
#endif
if( p + len != end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
ssl_write_version( ssl->handshake->max_major_ver,
ssl->handshake->max_minor_ver,
ssl->transport, ver );
ret = pk_decrypt( ssl_own_key( ssl ), p, len,
pms, &ssl->handshake->pmslen,
sizeof( ssl->handshake->premaster ) - pms_offset,
ssl->f_rng, ssl->p_rng );
if( ret != 0 || ssl->handshake->pmslen != 48 ||
pms[0] != ver[0] ||
pms[1] != ver[1] )
{
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, pms, ssl->handshake->pmslen );
if( ret != 0 )
return( ret );
}
return( ret );
}
#endif /* POLARSSL_KEY_EXCHANGE_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
static int ssl_parse_client_psk_identity( ssl_context *ssl, unsigned char **p,
const unsigned char *end )
{
int ret = 0;
size_t n;
if( ssl->f_psk == NULL &&
( ssl->psk == NULL || ssl->psk_identity == NULL ||
ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) )
{
SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* Receive client pre-shared key identity name
*/
if( *p + 2 > end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
n = ( (*p)[0] << 8 ) | (*p)[1];
*p += 2;
if( n < 1 || n > 65535 || *p + n > end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->f_psk != NULL )
{
if( ssl->f_psk( ssl->p_psk, ssl, *p, n ) != 0 )
ret = POLARSSL_ERR_SSL_UNKNOWN_IDENTITY;
}
else
{
/* Identity is not a big secret since clients send it in the clear,
* but treat it carefully anyway, just in case */
if( n != ssl->psk_identity_len ||
safer_memcmp( ssl->psk_identity, *p, n ) != 0 )
{
ret = POLARSSL_ERR_SSL_UNKNOWN_IDENTITY;
}
}
if( ret == POLARSSL_ERR_SSL_UNKNOWN_IDENTITY )
{
SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
if( ( ret = ssl_send_alert_message( ssl,
SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY ) ) != 0 )
{
return( ret );
}
return( POLARSSL_ERR_SSL_UNKNOWN_IDENTITY );
}
*p += n;
return( 0 );
}
#endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */
static int ssl_parse_client_key_exchange( ssl_context *ssl )
{
int ret;
const ssl_ciphersuite_t *ciphersuite_info;
ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
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 defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA )
{
unsigned char *p = ssl->in_msg + 4;
unsigned char *end = ssl->in_msg + ssl->in_hslen;
if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
return( ret );
}
if( p != end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
ssl->handshake->pmslen = POLARSSL_PREMASTER_SIZE;
if( ( ret = dhm_calc_secret( &ssl->handshake->dhm_ctx,
ssl->handshake->premaster,
&ssl->handshake->pmslen,
ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_calc_secret", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
}
SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
}
else
#endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_ECDSA )
{
if( ( ret = ecdh_read_public( &ssl->handshake->ecdh_ctx,
ssl->in_msg + 4, ssl->in_hslen - 4 ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ecdh_read_public", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
SSL_DEBUG_ECP( 3, "ECDH: Qp ", &ssl->handshake->ecdh_ctx.Qp );
if( ( ret = ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
&ssl->handshake->pmslen,
ssl->handshake->premaster,
POLARSSL_MPI_MAX_SIZE,
ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ecdh_calc_secret", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
}
SSL_DEBUG_MPI( 3, "ECDH: z ", &ssl->handshake->ecdh_ctx.z );
}
else
#endif /* POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK )
{
unsigned char *p = ssl->in_msg + 4;
unsigned char *end = ssl->in_msg + ssl->in_hslen;
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( p != end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* POLARSSL_KEY_EXCHANGE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK )
{
unsigned char *p = ssl->in_msg + 4;
unsigned char *end = ssl->in_msg + ssl->in_hslen;
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
return( ret );
}
if( ( ret = ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
{
unsigned char *p = ssl->in_msg + 4;
unsigned char *end = ssl->in_msg + ssl->in_hslen;
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
return( ret );
}
if( p != end )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
{
unsigned char *p = ssl->in_msg + 4;
unsigned char *end = ssl->in_msg + ssl->in_hslen;
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = ecdh_read_public( &ssl->handshake->ecdh_ctx,
p, end - p ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ecdh_read_public", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
SSL_DEBUG_ECP( 3, "ECDH: Qp ", &ssl->handshake->ecdh_ctx.Qp );
if( ( ret = ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
#if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED)
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA )
{
if( ( ret = ssl_parse_encrypted_pms( ssl,
ssl->in_msg + 4,
ssl->in_msg + ssl->in_hslen,
0 ) ) != 0 )
{
SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
return( ret );
}
}
else
#endif /* POLARSSL_KEY_EXCHANGE_RSA_ENABLED */
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
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 );
}
#if !defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
!defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
static int ssl_parse_certificate_verify( ssl_context *ssl )
{
const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
{
SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
ssl->state++;
return( 0 );
}
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
#else
static int ssl_parse_certificate_verify( ssl_context *ssl )
{
int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
size_t sa_len, sig_len;
unsigned char hash[48];
unsigned char *hash_start = hash;
size_t hashlen;
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
pk_type_t pk_alg;
#endif
md_type_t md_alg;
const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK )
{
SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
ssl->state++;
return( 0 );
}
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 );
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 sig alg (TLS 1.2 only)
* 4+n . 5+n signature length (n = sa_len)
* 6+n . 6+n+m signature (m = sig_len)
*/
#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
defined(POLARSSL_SSL_PROTO_TLS1_1)
if( ssl->minor_ver != SSL_MINOR_VERSION_3 )
{
sa_len = 0;
md_alg = POLARSSL_MD_NONE;
hashlen = 36;
/* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
if( pk_can_do( &ssl->session_negotiate->peer_cert->pk,
POLARSSL_PK_ECDSA ) )
{
hash_start += 16;
hashlen -= 16;
md_alg = POLARSSL_MD_SHA1;
}
}
else
#endif /* POLARSSL_SSL_PROTO_SSL3 || POLARSSL_SSL_PROTO_TLS1 ||
POLARSSL_SSL_PROTO_TLS1_1 */
#if defined(POLARSSL_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
sa_len = 2;
/*
* Hash
*/
if( ssl->in_msg[4] != ssl->handshake->verify_sig_alg )
{
SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
" for verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
md_alg = ssl_md_alg_from_hash( ssl->handshake->verify_sig_alg );
/* Info from md_alg will be used instead */
hashlen = 0;
/*
* Signature
*/
if( ( pk_alg = ssl_pk_alg_from_sig( ssl->in_msg[5] ) )
== POLARSSL_PK_NONE )
{
SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
" for verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
/*
* Check the certificate's key type matches the signature alg
*/
if( ! pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
{
SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
}
else
#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
sig_len = ( ssl->in_msg[4 + sa_len] << 8 ) | ssl->in_msg[5 + sa_len];
if( sa_len + sig_len + 6 != ssl->in_hslen )
{
SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
if( ( ret = pk_verify( &ssl->session_negotiate->peer_cert->pk,
md_alg, hash_start, hashlen,
ssl->in_msg + 6 + sa_len, sig_len ) ) != 0 )
{
SSL_DEBUG_RET( 1, "pk_verify", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
return( ret );
}
#endif /* !POLARSSL_KEY_EXCHANGE_RSA_ENABLED &&
!POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED &&
!POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED */
#if defined(POLARSSL_SSL_SESSION_TICKETS)
static int ssl_write_new_session_ticket( ssl_context *ssl )
{
int ret;
size_t tlen;
uint32_t lifetime = (uint32_t) ssl->ticket_lifetime;
SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_NEW_SESSION_TICKET;
/*
* struct {
* uint32 ticket_lifetime_hint;
* opaque ticket<0..2^16-1>;
* } NewSessionTicket;
*
* 4 . 7 ticket_lifetime_hint (0 = unspecified)
* 8 . 9 ticket_len (n)
* 10 . 9+n ticket content
*/
ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF;
ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF;
ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF;
ssl->out_msg[7] = ( lifetime ) & 0xFF;
if( ( ret = ssl_write_ticket( ssl, &tlen ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_ticket", ret );
tlen = 0;
}
ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );
ssl->out_msglen = 10 + tlen;
/*
* Morally equivalent to updating ssl->state, but NewSessionTicket and
* ChangeCipherSpec share the same state.
*/
ssl->handshake->new_session_ticket = 0;
if( ( ret = ssl_write_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_record", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
return( 0 );
}
#endif /* POLARSSL_SSL_SESSION_TICKETS */
/*
* SSL handshake -- server side -- single step
*/
int ssl_handshake_server_step( ssl_context *ssl )
{
int ret = 0;
if( ssl->state == SSL_HANDSHAKE_OVER )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
if( ( ret = ssl_flush_output( ssl ) ) != 0 )
return( ret );
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;
/*
* ==> ( NewSessionTicket )
* ChangeCipherSpec
* Finished
*/
case SSL_SERVER_CHANGE_CIPHER_SPEC:
#if defined(POLARSSL_SSL_SESSION_TICKETS)
if( ssl->handshake->new_session_ticket != 0 )
ret = ssl_write_new_session_ticket( ssl );
else
#endif
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 );
}
return( ret );
}
#endif /* POLARSSL_SSL_SRV_C */
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