commit 5c28e7aa0ebfa3d025e7802ae29eb86e43b0e92f
author Jerry Yu <jerry.h.yu@arm.com> Sat Jul 30 23:22:08 2022 +0800
committer Jerry Yu <jerry.h.yu@arm.com> Thu Aug 11 21:25:35 2022 +0800
tree 13db39c502018fc8457cb65d5b25bdddb8abf152
parent 56acc9421ce52d7e508cbe4bfbe453be75949589

remove psk key when ephemeral selected

ephemeral is selected, `handshake->psk` must be removed.
Otherwise the encrypt key will be caculate fail.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>

library/ssl_misc.h

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index e76086a..33a6533 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2498,6 +2498,13 @@
 int mbedtls_ssl_tls13_write_binders_of_pre_shared_key_ext(
     mbedtls_ssl_context *ssl,
     unsigned char *buf, unsigned char *end );
+
+/**
+ * \brief Remove psk from handshake context
+ *
+ * \param[in]   ssl     SSL context
+ */
+void mbedtls_ssl_remove_psk( mbedtls_ssl_context *ssl );
 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
 
 #endif /* ssl_misc.h */

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index fe38a09..1cda3a7 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1662,7 +1662,7 @@
     return( ret );
 }
 
-static void ssl_remove_psk( mbedtls_ssl_context *ssl )
+void mbedtls_ssl_remove_psk( mbedtls_ssl_context *ssl )
 {
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
@@ -1682,6 +1682,7 @@
         mbedtls_platform_zeroize( ssl->handshake->psk,
                                   ssl->handshake->psk_len );
         mbedtls_free( ssl->handshake->psk );
+        ssl->handshake->psk = NULL;
         ssl->handshake->psk_len = 0;
     }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
@@ -1703,7 +1704,7 @@
     if( psk_len > MBEDTLS_PSK_MAX_LEN )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
-    ssl_remove_psk( ssl );
+    mbedtls_ssl_remove_psk( ssl );
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
@@ -1780,7 +1781,7 @@
         ( ssl->handshake == NULL ) )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
-    ssl_remove_psk( ssl );
+    mbedtls_ssl_remove_psk( ssl );
     ssl->handshake->psk_opaque = psk;
     return( 0 );
 }
@@ -3522,25 +3523,7 @@
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
-    if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
-    {
-        /* The maintenance of the external PSK key slot is the
-         * user's responsibility. */
-        if( ssl->handshake->psk_opaque_is_internal )
-        {
-            psa_destroy_key( ssl->handshake->psk_opaque );
-            ssl->handshake->psk_opaque_is_internal = 0;
-        }
-        ssl->handshake->psk_opaque = MBEDTLS_SVC_KEY_ID_INIT;
-    }
-#else
-    if( handshake->psk != NULL )
-    {
-        mbedtls_platform_zeroize( handshake->psk, handshake->psk_len );
-        mbedtls_free( handshake->psk );
-    }
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
+    mbedtls_ssl_remove_psk( ssl );
 #endif
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && \

library/ssl_tls13_server.c

diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 15656fe..d527959 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -761,6 +761,9 @@
     else
     if( ssl_tls13_check_ephemeral_key_exchange( ssl ) )
     {
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+        mbedtls_ssl_remove_psk( ssl );
+#endif
         ssl->handshake->key_exchange_mode =
             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL;
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "key exchange mode: ephemeral" ) );