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mbedtls/library/ssl_srv.c
Manuel Pégourié-Gonnard a701d2f5e9 Fix bug in server parsing point formats extension 
There is only one length byte but for some reason we skipped two, resulting in
reading one byte past the end of the extension. Fortunately, even if that
extension is at the very end of the ClientHello, it can't be at the end of the
buffer since the ClientHello length is at most SSL_MAX_CONTENT_LEN and the
buffer has some more room after that for MAC and so on. So there is no
buffer overread.

Possible consequences are:
- nothing, if the next byte is 0x00, which is a comment first byte for other
  extensions, which is why the bug remained unnoticed
- using a point format that was not offered by the peer if next byte is 0x01.
  In that case the peer will reject our ServerKeyExchange message and the
handshake will fail.
- thinking that we don't have a common point format even if we do, which will
  cause us to immediately abort the handshake.
None of these are a security issue.

The same bug was fixed client-side in fd35af15

Backport of f7022d1
2015-09-17 11:46:56 +02:00

3629 lines
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/*
* SSLv3/TLSv1 server-side functions
*
* Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
*
* This file is part of mbed TLS (https://tls.mbed.org)
*
* 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"
#include <string.h>
#if defined(POLARSSL_ECP_C)
#include "polarssl/ecp.h"
#endif
#if defined(POLARSSL_PLATFORM_C)
#include "polarssl/platform.h"
#else
#include <stdlib.h>
#define polarssl_malloc malloc
#define polarssl_free free
#endif
#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->hanshake->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 defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
/* 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 renegotiation info" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
else
#endif /* POLARSSL_SSL_RENEGOTIATION */
{
if( len != 1 || buf[0] != 0x0 )
{
SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
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;
}
return( 0 );
}
#if defined(POLARSSL_SSL_PROTO_TLS1_2) && \
defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED)
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 &&
POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */
#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 + 1;
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);
if( ssl->trunc_hmac == SSL_TRUNC_HMAC_ENABLED )
ssl->session_negotiate->trunc_hmac = SSL_TRUNC_HMAC_ENABLED;
return( 0 );
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_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);
if( ssl->encrypt_then_mac == SSL_ETM_ENABLED &&
ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED;
}
return( 0 );
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_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);
if( ssl->extended_ms == SSL_EXTENDED_MS_ENABLED &&
ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
ssl->handshake->extended_ms = SSL_EXTENDED_MS_ENABLED;
}
return( 0 );
}
#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
#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 defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
return( 0 );
}
#endif /* POLARSSL_SSL_RENEGOTIATION */
/*
* 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 0 if the given key uses one of the acceptable curves, -1 otherwise
*/
#if defined(POLARSSL_ECDSA_C)
static int ssl_check_key_curve( 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( 0 );
crv++;
}
return( -1 );
}
#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, *fallback = NULL;
pk_type_t pk_alg = ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
int flags;
#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 );
SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
for( cur = list; cur != NULL; cur = cur->next )
{
SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
cur->cert );
if( ! pk_can_do( cur->key, pk_alg ) )
{
SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
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, &flags ) != 0 )
{
SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
"(extended) key usage extension" ) );
continue;
}
#if defined(POLARSSL_ECDSA_C)
if( pk_alg == POLARSSL_PK_ECDSA &&
ssl_check_key_curve( cur->key, ssl->handshake->curves ) != 0 )
{
SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
continue;
}
#endif
/*
* Try to select a SHA-1 certificate for pre-1.2 clients, but still
* present them a SHA-higher cert rather than failing if it's the only
* one we got that satisfies the other conditions.
*/
if( ssl->minor_ver < SSL_MINOR_VERSION_3 &&
cur->cert->sig_md != POLARSSL_MD_SHA1 )
{
if( fallback == NULL )
fallback = cur;
{
SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
"sha-2 with pre-TLS 1.2 client" ) );
continue;
}
}
/* If we get there, we got a winner */
break;
}
if( cur == NULL )
cur = fallback;
/* Do not update ssl->handshake->key_cert unless the is a match */
if( cur != NULL )
{
ssl->handshake->key_cert = cur;
SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
ssl->handshake->key_cert->cert );
return( 0 );
}
return( -1 );
}
#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, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %s", suite_info->name ) );
if( suite_info->min_minor_ver > ssl->minor_ver ||
suite_info->max_minor_ver < ssl->minor_ver )
{
SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
return( 0 );
}
if( ssl->arc4_disabled == SSL_ARC4_DISABLED &&
suite_info->cipher == POLARSSL_CIPHER_ARC4_128 )
{
SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) );
return( 0 );
}
#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 ) )
{
SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
"no common elliptic curve" ) );
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 ) )
{
SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
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 )
{
SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
"no suitable certificate" ) );
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, got_common_suite;
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 defined(POLARSSL_SSL_RENEGOTIATION)
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 );
}
#endif /* POLARSSL_SSL_RENEGOTIATION */
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 defined(POLARSSL_SSL_RENEGOTIATION)
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 );
}
#endif /* POLARSSL_SSL_RENEGOTIATION */
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
break;
}
}
#if defined(POLARSSL_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 &&
p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV >> 8 ) & 0xff ) &&
p[2] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 0xff ) )
{
SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* POLARSSL_SSL_FALLBACK_SCSV */
got_common_suite = 0;
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;
got_common_suite = 1;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite_v2;
}
}
if( got_common_suite )
{
SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
"but none of them usable" ) );
return( POLARSSL_ERR_SSL_NO_USABLE_CIPHERSUITE );
}
else
{
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
}
have_ciphersuite_v2:
SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
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, got_common_suite;
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;
#if defined(POLARSSL_SSL_RENEGOTIATION)
int renegotiation_info_seen = 0;
#endif
int handshake_failure = 0;
const int *ciphersuites;
const ssl_ciphersuite_t *ciphersuite_info;
SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
#if defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
#endif
{
if( ( ret = ssl_fetch_input( ssl, 5 ) ) != 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( ( buf[0] & 0x80 ) != 0 )
return ssl_parse_client_hello_v2( ssl );
#endif
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/TLS Client Hello
*
* Record layer:
* 0 . 0 message type
* 1 . 2 protocol version
* 3 . 4 message length
*/
/* 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( 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 > SSL_MAX_CONTENT_LEN )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#if defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
#endif
{
if( ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
}
buf = ssl->in_msg;
#if defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
n = ssl->in_msglen;
else
#endif
n = ssl->in_left - 5;
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 . 40+y ciphersuitelist
* 41+y . 41+y compression alg length
* 42+y . 41+z compression algs
* .. . .. 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 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->major_ver = buf[4];
ssl->minor_ver = buf[5];
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;
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 || sess_len > n - 42 )
{
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 % 2 ) != 0 || ciph_len > n - 42 - sess_len )
{
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 ||
comp_len > n - 42 - sess_len - ciph_len )
{
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 defined(POLARSSL_SSL_RENEGOTIATION)
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 );
}
renegotiation_info_seen = 1;
#endif /* POLARSSL_SSL_RENEGOTIATION */
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
break;
}
}
#if defined(POLARSSL_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 )
{
if( p[0] == (unsigned char)( ( SSL_FALLBACK_SCSV >> 8 ) & 0xff ) &&
p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 0xff ) )
{
SSL_DEBUG_MSG( 0, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 0, ( "inapropriate fallback" ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* POLARSSL_SSL_FALLBACK_SCSV */
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 )
{
#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" ) );
#if defined(POLARSSL_SSL_RENEGOTIATION)
renegotiation_info_seen = 1;
#endif
ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#if defined(POLARSSL_SSL_PROTO_TLS1_2) && \
defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED)
case TLS_EXT_SIG_ALG:
SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
#if defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation == SSL_RENEGOTIATION )
break;
#endif
ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_PROTO_TLS1_2 &&
POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */
#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_ENCRYPT_THEN_MAC)
case TLS_EXT_ENCRYPT_THEN_MAC:
SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
case TLS_EXT_EXTENDED_MASTER_SECRET:
SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
#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 );
}
}
/*
* Renegotiation security checks
*/
if( ssl->secure_renegotiation != SSL_SECURE_RENEGOTIATION &&
ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
handshake_failure = 1;
}
#if defined(POLARSSL_SSL_RENEGOTIATION)
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;
}
#endif /* POLARSSL_SSL_RENEGOTIATION */
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.)
*/
got_common_suite = 0;
ciphersuites = ssl->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(POLARSSL_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
for( j = 0, p = buf + 41 + sess_len; 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 + 41 + sess_len; j < ciph_len; j += 2, p += 2 )
#endif
{
if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
continue;
got_common_suite = 1;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite;
}
}
if( got_common_suite )
{
SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
"but none of them usable" ) );
ssl_send_fatal_handshake_failure( ssl );
return( POLARSSL_ERR_SSL_NO_USABLE_CIPHERSUITE );
}
else
{
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
ssl_send_fatal_handshake_failure( ssl );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
}
have_ciphersuite:
SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
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_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const ssl_ciphersuite_t *suite = NULL;
const cipher_info_t *cipher = NULL;
if( ssl->session_negotiate->encrypt_then_mac == SSL_EXTENDED_MS_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
/*
* RFC 7366: "If a server receives an encrypt-then-MAC request extension
* from a client and then selects a stream or Authenticated Encryption
* with Associated Data (AEAD) ciphersuite, it MUST NOT send an
* encrypt-then-MAC response extension back to the client."
*/
if( ( suite = ssl_ciphersuite_from_id(
ssl->session_negotiate->ciphersuite ) ) == NULL ||
( cipher = cipher_info_from_type( suite->cipher ) ) == NULL ||
cipher->mode != POLARSSL_MODE_CBC )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->handshake->extended_ms == SSL_EXTENDED_MS_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
"extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
#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 );
#if defined(POLARSSL_SSL_RENEGOTIATION)
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
*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;
}
else
#endif /* POLARSSL_SSL_RENEGOTIATION */
{
*p++ = 0x00;
*p++ = 0x01;
*p++ = 0x00;
*olen = 5;
}
}
#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;
*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] ) );
#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 &&
#if defined(POLARSSL_SSL_RENEGOTIATION)
ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
#endif
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_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_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 || *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 fake_pms[48], peer_pms[48];
unsigned char mask;
size_t i, peer_pmslen;
unsigned int diff;
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 );
}
/*
* 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.
* Also, avoid data-dependant branches here to protect against
* timing-based variants.
*/
ret = ssl->f_rng( ssl->p_rng, fake_pms, sizeof( fake_pms ) );
if( ret != 0 )
return( ret );
ret = pk_decrypt( ssl_own_key( ssl ), p, len,
peer_pms, &peer_pmslen,
sizeof( peer_pms ),
ssl->f_rng, ssl->p_rng );
diff = (unsigned int) ret;
diff |= peer_pmslen ^ 48;
diff |= peer_pms[0] ^ ssl->handshake->max_major_ver;
diff |= peer_pms[1] ^ ssl->handshake->max_minor_ver;
#if defined(POLARSSL_SSL_DEBUG_ALL)
if( diff != 0 )
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
#endif
if( sizeof( ssl->handshake->premaster ) < pms_offset ||
sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
ssl->handshake->pmslen = 48;
/* mask = diff ? 0xff : 0x00 */
mask = - ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 );
for( i = 0; i < ssl->handshake->pmslen; i++ )
pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
return( 0 );
}
#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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