Merge remote-tracking branch 'origin/pr/2538' into development

* origin/pr/2538:
  Remove unneeded whitespaces
  Fix mingw CI failures
  Initialize psa_crypto in ssl test
  Fix missing tls version test failures
  Fix typo
  Fix ChangeLog entry location
  Add changeLog entry
  Add test for export keys functionality
  Add function to retrieve the tls_prf type
  Add tests for the public tls_prf API
  Add public API for tls_prf
  Add eap-tls key derivation in the examples.
  Add ChangeLog entry
  Add an extra key export function
  Have the temporary buffer allocated dynamically
  Zeroize secret data in the exit point
  Add a single exit point in key derivation function

include/mbedtls/ssl.h

@@ -450,6 +450,18 @@ typedef enum
 }
 mbedtls_ssl_states;
 
+/*
+ * The tls_prf function types.
+ */
+typedef enum
+{
+   MBEDTLS_SSL_TLS_PRF_NONE,
+   MBEDTLS_SSL_TLS_PRF_SSL3,
+   MBEDTLS_SSL_TLS_PRF_TLS1,
+   MBEDTLS_SSL_TLS_PRF_SHA384,
+   MBEDTLS_SSL_TLS_PRF_SHA256
+}
+mbedtls_tls_prf_types;
 /**
  * \brief          Callback type: send data on the network.
  *
@@ -920,6 +932,11 @@ struct mbedtls_ssl_config
     /** Callback to export key block and master secret                      */
     int (*f_export_keys)( void *, const unsigned char *,
             const unsigned char *, size_t, size_t, size_t );
+    /** Callback to export key block, master secret,
+     *  tls_prf and random bytes. Should replace f_export_keys    */
+    int (*f_export_keys_ext)( void *, const unsigned char *,
+                const unsigned char *, size_t, size_t, size_t,
+                unsigned char[32], unsigned char[32], mbedtls_tls_prf_types );
     void *p_export_keys;            /*!< context for key export callback    */
 #endif
 
@@ -1624,6 +1641,41 @@ typedef int mbedtls_ssl_export_keys_t( void *p_expkey,
                                 size_t maclen,
                                 size_t keylen,
                                 size_t ivlen );
+
+/**
+ * \brief           Callback type: Export key block, master secret,
+ *                                 handshake randbytes and the tls_prf function
+ *                                 used to derive keys.
+ *
+ * \note            This is required for certain uses of TLS, e.g. EAP-TLS
+ *                  (RFC 5216) and Thread. The key pointers are ephemeral and
+ *                  therefore must not be stored. The master secret and keys
+ *                  should not be used directly except as an input to a key
+ *                  derivation function.
+ *
+ * \param p_expkey  Context for the callback.
+ * \param ms        Pointer to master secret (fixed length: 48 bytes).
+ * \param kb            Pointer to key block, see RFC 5246 section 6.3.
+ *                      (variable length: 2 * maclen + 2 * keylen + 2 * ivlen).
+ * \param maclen        MAC length.
+ * \param keylen        Key length.
+ * \param ivlen         IV length.
+ * \param client_random The client random bytes.
+ * \param server_random The server random bytes.
+ * \param tls_prf_type The tls_prf enum type.
+ *
+ * \return          0 if successful, or
+ *                  a specific MBEDTLS_ERR_XXX code.
+ */
+typedef int mbedtls_ssl_export_keys_ext_t( void *p_expkey,
+                                           const unsigned char *ms,
+                                           const unsigned char *kb,
+                                           size_t maclen,
+                                           size_t keylen,
+                                           size_t ivlen,
+                                           unsigned char client_random[32],
+                                           unsigned char server_random[32],
+                                           mbedtls_tls_prf_types tls_prf_type );
 #endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 /**
@@ -1689,6 +1741,20 @@ void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
 void mbedtls_ssl_conf_export_keys_cb( mbedtls_ssl_config *conf,
         mbedtls_ssl_export_keys_t *f_export_keys,
         void *p_export_keys );
+
+/**
+ * \brief           Configure extended key export callback.
+ *                  (Default: none.)
+ *
+ * \note            See \c mbedtls_ssl_export_keys_ext_t.
+ *
+ * \param conf      SSL configuration context
+ * \param f_export_keys_ext Callback for exporting keys
+ * \param p_export_keys     Context for the callback
+ */
+void mbedtls_ssl_conf_export_keys_ext_cb( mbedtls_ssl_config *conf,
+        mbedtls_ssl_export_keys_ext_t *f_export_keys_ext,
+        void *p_export_keys );
 #endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
@@ -3487,6 +3553,27 @@ void mbedtls_ssl_session_init( mbedtls_ssl_session *session );
  */
 void mbedtls_ssl_session_free( mbedtls_ssl_session *session );
 
+/**
+ * \brief          TLS-PRF function for key derivation.
+ *
+ * \param prf      The tls_prf type funtion type to be used.
+ * \param secret   Secret for the key derivation function.
+ * \param slen     Length of the secret.
+ * \param label    String label for the key derivation function,
+ *                 terminated with null character.
+ * \param random   Random bytes.
+ * \param rlen     Length of the random bytes buffer.
+ * \param dstbuf   The buffer holding the derived key.
+ * \param dlen     Length of the output buffer.
+ *
+ * \return         0 on sucess. An SSL specific error on failure.
+ */
+int  mbedtls_ssl_tls_prf( const mbedtls_tls_prf_types prf,
+                          const unsigned char *secret, size_t slen,
+                          const char *label,
+                          const unsigned char *random, size_t rlen,
+                          unsigned char *dstbuf, size_t dlen );
+
 #ifdef __cplusplus
 }
 #endif

include/mbedtls/ssl_internal.h

@@ -276,6 +276,10 @@ struct mbedtls_ssl_sig_hash_set_t
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
           MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
 
+typedef int  mbedtls_ssl_tls_prf_cb( const unsigned char *secret, size_t slen,
+                                     const char *label,
+                                     const unsigned char *random, size_t rlen,
+                                     unsigned char *dstbuf, size_t dlen );
 /*
  * This structure contains the parameters only needed during handshake.
  */
@@ -425,9 +429,7 @@ struct mbedtls_ssl_handshake_params
     void (*update_checksum)(mbedtls_ssl_context *, const unsigned char *, size_t);
     void (*calc_verify)(mbedtls_ssl_context *, unsigned char *);
     void (*calc_finished)(mbedtls_ssl_context *, unsigned char *, int);
-    int  (*tls_prf)(const unsigned char *, size_t, const char *,
-                    const unsigned char *, size_t,
-                    unsigned char *, size_t);
+    mbedtls_ssl_tls_prf_cb *tls_prf;
 
     mbedtls_ssl_ciphersuite_t const *ciphersuite_info;