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Add HRR handler

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Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
This commit is contained in:
Jerry Yu 2022-04-22 21:59:01 +08:00
parent fe24d1c9f5
commit 582dd069b7
2 changed files with 265 additions and 11 deletions
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7
library/ssl_misc.h
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@ -585,17 +585,14 @@ struct mbedtls_ssl_handshake_params
*/
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
int tls13_kex_modes; /*!< key exchange modes for TLS 1.3 */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
#if defined(MBEDTLS_SSL_CLI_C)
/** Number of Hello Retry Request messages received from the server. */
/* Number of HelloRetryRequest messages received/sent from the server. */
int hello_retry_request_count;
#endif /* MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SRV_C)
/** selected_group of key_share extension in HelloRetryRequest message. */
uint16_t hrr_selected_group;
#endif /* MBEDTLS_SSL_SRV_C */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)

269
library/ssl_tls13_server.c
View File

@ -388,6 +388,7 @@ static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl,
const unsigned char *cipher_suites_end;
size_t extensions_len;
const unsigned char *extensions_end;
int hrr_required = SSL_CLIENT_HELLO_OK;
const mbedtls_ssl_ciphersuite_t* ciphersuite_info;
@ -611,11 +612,15 @@ static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl,
if( ret == SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "HRR needed " ) );
ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
hrr_required |= SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH;
}
if( ret != 0 )
if( ret < 0 )
{
MBEDTLS_SSL_DEBUG_RET(
1, "ssl_tls13_parse_key_shares_ext", ret );
return( ret );
}
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE;
break;
@ -687,9 +692,11 @@ static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl,
return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
}
return( 0 );
return( hrr_required );
}
/* Update the handshake state machine */
static int ssl_tls13_postprocess_client_hello( mbedtls_ssl_context* ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@ -716,6 +723,7 @@ static int ssl_tls13_process_client_hello( mbedtls_ssl_context *ssl )
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char* buf = NULL;
size_t buflen = 0;
int hrr_required ;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg(
@ -724,8 +732,14 @@ static int ssl_tls13_process_client_hello( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_parse_client_hello( ssl, buf,
buf + buflen ) );
hrr_required = ret;
MBEDTLS_SSL_PROC_CHK( ssl_tls13_postprocess_client_hello( ssl ) );
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO );
if( hrr_required == SSL_CLIENT_HELLO_OK )
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO );
else
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HELLO_RETRY_REQUEST );
cleanup:
@ -1280,10 +1294,252 @@ cleanup:
* Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST
*/
static int ssl_tls13_write_hello_retry_request_coordinate(
mbedtls_ssl_context *ssl )
{
int ret;
if( ssl->handshake->hello_retry_request_count > 1 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Too many HRRs" ) );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
/*
* Create stateless transcript hash for HRR
*/
MBEDTLS_SSL_DEBUG_MSG( 4, ( "Reset transcript for HRR" ) );
ret = mbedtls_ssl_reset_transcript_for_hrr( ssl );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_reset_transcript_for_hrr", ret );
return( ret );
}
mbedtls_ssl_session_reset_msg_layer( ssl, 0 );
return( 0 );
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
static int ssl_tls13_write_hrr_key_share_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *out_len )
{
uint16_t selected_group = ssl->handshake->hrr_selected_group;
/* key_share Extension
*
* struct {
* select (Handshake.msg_type) {
* ...
* case hello_retry_request:
* NamedGroup selected_group;
* ...
* };
* } KeyShare;
*/
*out_len = 0;
/* For a pure PSK-based ciphersuite there is no key share to declare. */
if( ! mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
return( 0 );
/* We should only send the key_share extension if the client's initial
* key share was not acceptable. */
if( ssl->handshake->offered_group_id != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 4, ( "Skip key_share extension in HRR" ) );
return( 0 );
}
if( selected_group == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching named group found" ) );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
if( ! mbedtls_ssl_named_group_is_offered( ssl, selected_group ) ||
! mbedtls_ssl_named_group_is_supported( selected_group ) )
{
MBEDTLS_SSL_DEBUG_MSG( 4, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* extension header, extension length, NamedGroup value */
MBEDTLS_SSL_CHK_BUF_READ_PTR( buf, end, 6 );
/* Write extension header */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 );
/* Write extension length */
MBEDTLS_PUT_UINT16_BE( 2, buf, 2 );
/* Write selected group */
MBEDTLS_PUT_UINT16_BE( selected_group, buf, 4 );
MBEDTLS_SSL_DEBUG_MSG( 3,
( "HRR selected_group: %s (%x)",
mbedtls_ssl_named_group_to_str( selected_group ),
selected_group ) );
*out_len = 6;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
static int ssl_tls13_write_hello_retry_request_body( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *out_len )
{
int ret;
unsigned char *p = buf;
unsigned char *start = buf;
size_t output_len;
unsigned char *extension_start;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello retry request" ) );
*out_len = 0;
/*
* struct {
* ProtocolVersion legacy_version = 0x0303;
* Random random ( with magic value );
* opaque legacy_session_id_echo<0..32>;
* CipherSuite cipher_suite;
* uint8 legacy_compression_method = 0;
* Extension extensions<0..2^16-1>;
* } ServerHello; --- aka HelloRetryRequest
*/
/*
* Write legacy_version
* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
*
* For TLS 1.3 we use the legacy version number {0x03, 0x03}
* instead of the true version number.
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
MBEDTLS_PUT_UINT16_BE( 0x0303, p, 0 );
p += 2;
/* write magic string (as a replacement for the random value) */
MBEDTLS_SSL_CHK_BUF_PTR( p, end, MBEDTLS_SERVER_HELLO_RANDOM_LEN );
memcpy( p, mbedtls_ssl_tls13_hello_retry_request_magic,
MBEDTLS_SERVER_HELLO_RANDOM_LEN );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes",
p, MBEDTLS_SERVER_HELLO_RANDOM_LEN );
p += MBEDTLS_SERVER_HELLO_RANDOM_LEN;
/*
* Write legacy_session_id_echo
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 + ssl->session_negotiate->id_len );
*p++ = (unsigned char)ssl->session_negotiate->id_len;
if( ssl->session_negotiate->id_len > 0 )
{
memcpy( p, &ssl->session_negotiate->id[0],
ssl->session_negotiate->id_len );
p += ssl->session_negotiate->id_len;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "session id length ( %"
MBEDTLS_PRINTF_SIZET " )",
ssl->session_negotiate->id_len ) );
MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id,
ssl->session_negotiate->id_len );
}
/*
* Write ciphersuite
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
MBEDTLS_PUT_UINT16_BE( ssl->session_negotiate->ciphersuite, p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3,
( "server hello, chosen ciphersuite: %s ( id=%d )",
mbedtls_ssl_get_ciphersuite_name(
ssl->session_negotiate->ciphersuite ),
ssl->session_negotiate->ciphersuite ) );
/* write legacy_compression_method = ( 0 ) */
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
*p++ = 0x0;
/* Extensions */
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
extension_start = p;
p += 2;
/* Add supported_version extension */
if( ( ret = ssl_tls13_write_server_hello_supported_versions_ext(
ssl, p, end, &output_len ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_selected_version_ext",
ret );
return( ret );
}
p += output_len;
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* Add key_share extension, if necessary */
if( mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
{
ret = ssl_tls13_write_hrr_key_share_ext( ssl, p, end, &output_len );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_hrr_key_share_ext", ret );
return( ret );
}
p += output_len;
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/* Write length information */
MBEDTLS_PUT_UINT16_BE( p - extension_start - 2, extension_start, 0 );
MBEDTLS_SSL_DEBUG_BUF( 4, "hello retry request extensions",
extension_start, p - extension_start );
*out_len = p - start;
MBEDTLS_SSL_DEBUG_BUF( 3, "hello retry request", start, *out_len );
*out_len = p - buf;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello retry request" ) );
return( 0 );
}
static int ssl_tls13_write_hello_retry_request( mbedtls_ssl_context *ssl )
{
((void) ssl);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
int ret;
unsigned char *buf;
size_t buf_len, msg_len;
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_hello_retry_request_coordinate( ssl ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl,
MBEDTLS_SSL_HS_SERVER_HELLO, &buf, &buf_len ) );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_hello_retry_request_body(
ssl, buf, buf + buf_len, &msg_len ) );
mbedtls_ssl_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( ssl, buf_len,
msg_len ) );
ssl->handshake->hello_retry_request_count++;
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
cleanup:
return( ret );
}
/*
@ -1304,6 +1560,7 @@ int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
{
/* start state */
case MBEDTLS_SSL_HELLO_REQUEST:
ssl->handshake->hello_retry_request_count = 0;
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
ret = 0;