Implement PSA server-side ECDHE-PSK
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index 486632e..1a4571c 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -3068,7 +3068,8 @@
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
- ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
+ ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
+ ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
{
psa_status_t status = PSA_ERROR_GENERIC_ERROR;
psa_key_attributes_t key_attributes;
@@ -4037,6 +4038,96 @@
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
+#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
+ if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
+ {
+ psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+ psa_status_t destruction_status = PSA_ERROR_CORRUPTION_DETECTED;
+ uint8_t ecpoint_len;
+
+ mbedtls_ssl_handshake_params *handshake = ssl->handshake;
+
+ if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
+ psa_destroy_key( handshake->ecdh_psa_privkey );
+ handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
+ return( ret );
+ }
+
+ /* Keep a copy of the peer's public key */
+ ecpoint_len = *(p++);
+ if( (size_t)( end - *p ) < ecpoint_len ) {
+ psa_destroy_key( handshake->ecdh_psa_privkey );
+ handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+
+ if( ecpoint_len > sizeof( handshake->ecdh_psa_peerkey ) ) {
+ psa_destroy_key( handshake->ecdh_psa_privkey );
+ handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
+ return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+ }
+
+ memcpy( handshake->ecdh_psa_peerkey, p, ecpoint_len );
+ handshake->ecdh_psa_peerkey_len = ecpoint_len;
+ p += ecpoint_len;
+
+ /* The ECDH secret is the premaster secret used for key derivation. */
+ unsigned char *psm = ssl->handshake->premaster;
+ unsigned char *psm_end = psm + sizeof( ssl->handshake->premaster );
+ size_t zlen;
+
+ /* Compute ECDH shared secret. */
+ status = psa_raw_key_agreement( PSA_ALG_ECDH,
+ handshake->ecdh_psa_privkey,
+ handshake->ecdh_psa_peerkey,
+ handshake->ecdh_psa_peerkey_len,
+ psm + 2,
+ psm_end - ( psm + 2 ),
+ &zlen );
+
+ destruction_status = psa_destroy_key( handshake->ecdh_psa_privkey );
+ handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
+
+ if( status != PSA_SUCCESS || destruction_status != PSA_SUCCESS )
+ return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
+
+ MBEDTLS_PUT_UINT16_BE( zlen, psm, 0 );
+ psm += 2 + zlen;
+
+ /* opaque psk<0..2^16-1>; */
+ if( psm_end - psm < 2 )
+ return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+ const unsigned char *psk = NULL;
+ size_t psk_len = 0;
+
+ if( mbedtls_ssl_get_psk( ssl, &psk, &psk_len )
+ == MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED )
+ {
+ /*
+ * This should never happen because the existence of a PSK is always
+ * checked before calling this function
+ */
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ MBEDTLS_PUT_UINT16_BE( psk_len, psm, 0 );
+ psm += 2;
+
+ if( psm_end < psm || (size_t)( psm_end - psm ) < psk_len )
+ return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+ memcpy( psm, psk, psk_len );
+ psm += psk_len;
+
+ ssl->handshake->pmslen = psm - ssl->handshake->premaster;
+ }
+ else
+#endif /* MBEDTLS_USE_PSA_CRYPTO &&
+ MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
{