Enable support for psa opaque ECDHE-PSK key exchange on the client side
Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index df6a793..c60a856 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5093,11 +5093,13 @@
}
#endif /* MBEDTLS_SSL_EXTENDED_MS_ENABLED */
-#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
- ( defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) || \
- defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
+#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
+ ( defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) )
if( ( handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
- handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ) &&
+ handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
+ handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ) &&
ssl_use_opaque_psk( ssl ) == 1 )
{
/* Perform PSK-to-MS expansion in a single step. */
@@ -5120,15 +5122,23 @@
size_t other_secret_len = 0;
unsigned char* other_secret = NULL;
- if ( handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
+ switch( handshake->ciphersuite_info->key_exchange )
{
- /* Provide other key as other secret.
- * For RSA-PKS other key length is always 48 bytes.
+ /* Provide other secret.
* Other secret is stored in premaster, where first 2 bytes hold the
- * length of the other key. Skip them.
+ * length of the other key.
*/
- other_secret_len = 48;
- other_secret = handshake->premaster + 2;
+ case MBEDTLS_KEY_EXCHANGE_RSA_PSK:
+ /* For RSA-PKS other key length is always 48 bytes. */
+ other_secret_len = 48;
+ other_secret = handshake->premaster + 2;
+ break;
+ case MBEDTLS_KEY_EXCHANGE_ECDHE_PSK:
+ other_secret_len = MBEDTLS_GET_UINT16_BE(handshake->premaster, 0);
+ other_secret = handshake->premaster + 2;
+ break;
+ default:
+ break;
}
status = setup_psa_key_derivation( &derivation, psk, alg,
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index aaffcd3..2868a84 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -2959,10 +2959,6 @@
* ciphersuites we offered, so this should never happen. */
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
- /* Opaque PSKs are currently only supported for PSK-only suites. */
- if( ssl_conf_has_static_raw_psk( ssl->conf ) == 0 )
- return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-
/* uint16 to store content length */
const size_t content_len_size = 2;
@@ -3068,30 +3064,40 @@
MBEDTLS_PUT_UINT16_BE( zlen, pms, 0 );
pms += zlen_size + zlen;
- const unsigned char *psk = NULL;
- size_t psk_len = 0;
+ /* In case of opaque psk skip writting psk to pms.
+ * Opaque key will be handled later. */
+ if( ssl_conf_has_static_raw_psk( ssl->conf ) == 1 )
+ {
+ 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 );
+ 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 );
- /* opaque psk<0..2^16-1>; */
- if( (size_t)( pms_end - pms ) < ( 2 + psk_len ) )
- return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+ /* opaque psk<0..2^16-1>; */
+ if( (size_t)( pms_end - pms ) < ( 2 + psk_len ) )
+ return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
- /* Write the PSK length as uint16 */
- MBEDTLS_PUT_UINT16_BE( psk_len, pms, 0 );
- pms += 2;
+ /* Write the PSK length as uint16 */
+ MBEDTLS_PUT_UINT16_BE( psk_len, pms, 0 );
+ pms += 2;
- /* Write the PSK itself */
- memcpy( pms, psk, psk_len );
- pms += psk_len;
+ /* Write the PSK itself */
+ memcpy( pms, psk, psk_len );
+ pms += psk_len;
- ssl->handshake->pmslen = pms - ssl->handshake->premaster;
+ ssl->handshake->pmslen = pms - ssl->handshake->premaster;
+ }
+ else
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1,
+ ( "skip PMS generation for opaque ECDHE-PSK" ) );
+ }
}
else
#endif /* MBEDTLS_USE_PSA_CRYPTO &&