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Merge pull request #5230 from ronald-cron-arm/tls13_ccs_client

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Add initial support for "Middlebox Compatibility Mode"
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Ronald Cron 2021-12-10 11:58:05 +01:00 • committed by GitHub
commit 6b07916e40
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 695 additions and 219 deletions
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5
library/ssl_misc.h
View file

@ -1676,6 +1676,11 @@ int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl );
*/
int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl );
/*
* Write of dummy-CCS's for middlebox compatibility
*/
int mbedtls_ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl );
/*
* Write TLS 1.3 handshake message tail
*/

29
library/ssl_msg.c
View file

@ -3335,6 +3335,20 @@ static int ssl_prepare_record_content( mbedtls_ssl_context *ssl,
MBEDTLS_SSL_DEBUG_BUF( 4, "input record from network",
rec->buf, rec->buf_len );
/*
* In TLS 1.3, always treat ChangeCipherSpec records
* as unencrypted. The only thing we do with them is
* check the length and content and ignore them.
*/
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
if( ssl->transform_in != NULL &&
ssl->transform_in->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 )
{
if( rec->type == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
done = 1;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
if( !done && ssl->transform_in != NULL )
{
unsigned char const old_msg_type = rec->type;
@ -4385,6 +4399,21 @@ int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl )
return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
}
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 )
{
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
MBEDTLS_SSL_DEBUG_MSG( 1,
( "Ignore ChangeCipherSpec in TLS 1.3 compatibility mode" ) );
return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
#else
MBEDTLS_SSL_DEBUG_MSG( 1,
( "ChangeCipherSpec invalid in TLS 1.3 without compatibility mode" ) );
return( MBEDTLS_ERR_SSL_INVALID_RECORD );
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
}
if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT )

66
library/ssl_tls13_client.c
View file

@ -723,8 +723,18 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
* ( also known as ossification ). Otherwise, it MUST be set as a zero-length
* vector ( i.e., a zero-valued single byte length field ).
*/
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
MBEDTLS_SSL_CHK_BUF_PTR( p, end, ssl->session_negotiate->id_len + 1 );
*p++ = (unsigned char)ssl->session_negotiate->id_len;
memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
p += ssl->session_negotiate->id_len;
MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id,
ssl->session_negotiate->id_len );
#else
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
*p++ = 0; /* session id length set to zero */
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
/* Write cipher_suites */
ret = ssl_tls13_write_client_hello_cipher_suites( ssl, p, end, &output_len );
@ -843,6 +853,24 @@ static int ssl_tls13_prepare_client_hello( mbedtls_ssl_context *ssl )
return( ret );
}
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
/*
* Create a session identifier for the purpose of middlebox compatibility
* only if one has not been created already.
*/
if( ssl->session_negotiate->id_len == 0 )
{
/* Creating a session id with 32 byte length */
if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng,
ssl->session_negotiate->id, 32 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "creating session id failed", ret );
return( ret );
}
ssl->session_negotiate->id_len = 32;
}
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
return( 0 );
}
@ -1600,6 +1628,7 @@ static int ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl )
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/*
* Handler for MBEDTLS_SSL_SERVER_FINISHED
*/
@ -1611,11 +1640,35 @@ static int ssl_tls13_process_server_finished( mbedtls_ssl_context *ssl )
if( ret != 0 )
return( ret );
mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
mbedtls_ssl_handshake_set_state(
ssl,
MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED );
#else
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
#endif
return( 0 );
}
/*
* Handler for MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED
*/
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
static int ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl )
{
int ret;
ret = mbedtls_ssl_tls13_write_change_cipher_spec( ssl );
if( ret != 0 )
return( ret );
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
return( 0 );
}
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
/*
* Handler for MBEDTLS_SSL_CLIENT_FINISHED
*/
@ -1623,6 +1676,8 @@ static int ssl_tls13_write_client_finished( mbedtls_ssl_context *ssl )
{
int ret;
mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
ret = mbedtls_ssl_tls13_write_finished_message( ssl );
if( ret != 0 )
return( ret );
@ -1713,6 +1768,15 @@ int mbedtls_ssl_tls13_handshake_client_step( mbedtls_ssl_context *ssl )
ret = ssl_tls13_handshake_wrapup( ssl );
break;
/*
* Injection of dummy-CCS's for middlebox compatibility
*/
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
case MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED:
ret = ssl_tls13_write_change_cipher_spec( ssl );
break;
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

48
library/ssl_tls13_generic.c
View file

@ -1148,6 +1148,54 @@ void mbedtls_ssl_tls13_handshake_wrapup( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
}
/*
*
* STATE HANDLING: Write ChangeCipherSpec
*
*/
#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
static int ssl_tls13_write_change_cipher_spec_body( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
((void) ssl);
MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 1 );
buf[0] = 1;
*olen = 1;
return( 0 );
}
int mbedtls_ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write change cipher spec" ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_flush_output( ssl ) );
/* Write CCS message */
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_change_cipher_spec_body(
ssl, ssl->out_msg,
ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
&ssl->out_msglen ) );
ssl->out_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC;
/* Dispatch message */
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_write_record( ssl, 1 ) );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write change cipher spec" ) );
return( ret );
}
#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#endif /* MBEDTLS_SSL_TLS_C */