Implement ServerKeyExchange parsing for PSA-based ECDHE suites

- Reformat the server's ECDH public key to make it suitable
  for the PSA key agreement API. Currently, the key agreement
  API needs a full SubjectPublicKeyInfo structure, while the
  TLS ServerKeyExchange message only contains a ECPoint structure.
This commit is contained in:
Hanno Becker 2019-01-08 12:54:37 +00:00
parent df51dbe17f
commit bb89e2727f

View file

@ -39,6 +39,10 @@
#include "mbedtls/ssl.h"
#include "mbedtls/ssl_internal.h"
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "mbedtls/psa_util.h"
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#include <string.h>
#include <stdint.h>
@ -2109,6 +2113,64 @@ static int ssl_check_server_ecdh_params( const mbedtls_ssl_context *ssl )
MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
( defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) )
static int ssl_parse_server_ecdh_params_psa( mbedtls_ssl_context *ssl,
unsigned char **p,
unsigned char *end )
{
uint16_t tls_id;
uint8_t ecpoint_len;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
/*
* Parse ECC group
*/
if( end - *p < 4 )
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
/* First byte is curve_type; only named_curve is handled */
if( *(*p)++ != MBEDTLS_ECP_TLS_NAMED_CURVE )
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
/* Next two bytes are the namedcurve value */
tls_id = *(*p)++;
tls_id <<= 8;
tls_id |= *(*p)++;
/* Convert EC group to PSA key type. */
if( ( handshake->ecdh_psa_curve =
mbedtls_psa_parse_tls_ecc_group( tls_id ) ) == 0 )
{
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
/*
* Put peer's ECDH public key in the format understood by PSA.
*/
ecpoint_len = *(*p)++;
if( (size_t)( end - *p ) < ecpoint_len )
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
if( mbedtls_psa_tls_ecpoint_to_psa_ec( handshake->ecdh_psa_curve,
*p, ecpoint_len,
handshake->ecdh_psa_peerkey,
sizeof( handshake->ecdh_psa_peerkey ),
&handshake->ecdh_psa_peerkey_len ) != 0 )
{
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
*p += ecpoint_len;
return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO &&
( MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ) */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
@ -2510,6 +2572,24 @@ start_processing:
else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
( defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) )
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
{
if( ssl_parse_server_ecdh_params_psa( ssl, &p, end ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
}
else
#endif /* MBEDTLS_USE_PSA_CRYPTO &&
( MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ) */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)