Fix DeriveTls13Keys with no_key

src/tls13.c

@@ -1453,6 +1453,8 @@ static const byte writeIVLabel[WRITE_IV_LABEL_SZ+1]   = "iv";
  *          traffic messages.
  *          update_traffic_key when deriving next keys and IVs for encrypting
  *          traffic messages.
+ *          no_key when deriving keys and IVs from existing secrets without
+ *          re-deriving the secrets. Used during early data transitions.
  * side     ENCRYPT_SIDE_ONLY when only encryption secret needs to be derived.
  *          DECRYPT_SIDE_ONLY when only decryption secret needs to be derived.
  *          ENCRYPT_AND_DECRYPT_SIDE when both secret needs to be derived.
@@ -1541,6 +1543,12 @@ int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store)
             }
             break;
 
+        case no_key:
+            /* Called with early data to derive keys from existing secrets
+             * without re-deriving the secrets themselves. */
+            ret = 0;
+            break;
+
         default:
             ret = BAD_FUNC_ARG;
             break;

tests/api/test_tls13.c

@@ -3317,3 +3317,38 @@ int test_tls13_cert_req_sigalgs(void)
     return EXPECT_RESULT();
 }
 
+int test_tls13_derive_keys_no_key(void)
+{
+    EXPECT_DECLS;
+#if defined(WOLFSSL_TLS13) && defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES)
+    struct test_memio_ctx test_ctx;
+    WOLFSSL_CTX *ctx_c = NULL;
+    WOLFSSL_CTX *ctx_s = NULL;
+    WOLFSSL *ssl_c = NULL;
+    WOLFSSL *ssl_s = NULL;
+
+    XMEMSET(&test_ctx, 0, sizeof(test_ctx));
+    ExpectIntEQ(test_memio_setup(&test_ctx, &ctx_c, &ctx_s, &ssl_c, &ssl_s,
+        wolfTLSv1_3_client_method, wolfTLSv1_3_server_method), 0);
+
+    /* DeriveTls13Keys with no_key should succeed (skip secret derivation,
+     * only derive keys/IVs from existing secrets). This is used with early
+     * data to derive keys without re-deriving the secrets. */
+    ExpectIntEQ(DeriveTls13Keys(ssl_s, no_key, DECRYPT_SIDE_ONLY, 0), 0);
+    ExpectIntEQ(DeriveTls13Keys(ssl_s, no_key, ENCRYPT_SIDE_ONLY, 0), 0);
+    ExpectIntEQ(DeriveTls13Keys(ssl_c, no_key, ENCRYPT_AND_DECRYPT_SIDE, 0),
+        0);
+
+    /* Unknown secret type should return BAD_FUNC_ARG */
+    ExpectIntEQ(DeriveTls13Keys(ssl_c, -1, ENCRYPT_SIDE_ONLY, 0),
+        WC_NO_ERR_TRACE(BAD_FUNC_ARG));
+
+    wolfSSL_free(ssl_c);
+    wolfSSL_free(ssl_s);
+    wolfSSL_CTX_free(ctx_c);
+    wolfSSL_CTX_free(ctx_s);
+#endif
+
+    return EXPECT_RESULT();
+}
+

tests/api/test_tls13.h

@@ -41,6 +41,7 @@ int test_tls13_plaintext_alert(void);
 int test_tls13_warning_alert_is_fatal(void);
 int test_tls13_unknown_ext_rejected(void);
 int test_tls13_cert_req_sigalgs(void);
+int test_tls13_derive_keys_no_key(void);
 
 #define TEST_TLS13_DECLS                                        \
     TEST_DECL_GROUP("tls13", test_tls13_apis),                  \
@@ -59,6 +60,7 @@ int test_tls13_cert_req_sigalgs(void);
     TEST_DECL_GROUP("tls13", test_tls13_plaintext_alert),       \
     TEST_DECL_GROUP("tls13", test_tls13_warning_alert_is_fatal), \
     TEST_DECL_GROUP("tls13", test_tls13_unknown_ext_rejected),  \
-    TEST_DECL_GROUP("tls13", test_tls13_cert_req_sigalgs)
+    TEST_DECL_GROUP("tls13", test_tls13_cert_req_sigalgs),       \
+    TEST_DECL_GROUP("tls13", test_tls13_derive_keys_no_key)
 
 #endif /* WOLFCRYPT_TEST_TLS13_H */

wolfssl/internal.h

@@ -3759,7 +3759,10 @@ enum DeriveKeyType {
 
 WOLFSSL_LOCAL int DeriveEarlySecret(WOLFSSL* ssl);
 WOLFSSL_LOCAL int DeriveHandshakeSecret(WOLFSSL* ssl);
-WOLFSSL_LOCAL int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store);
+#ifdef WOLFSSL_API_PREFIX_MAP
+    #define DeriveTls13Keys wolfSSL_DeriveTls13Keys
+#endif
+WOLFSSL_TEST_VIS int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store);
 WOLFSSL_LOCAL int DeriveMasterSecret(WOLFSSL* ssl);
 WOLFSSL_LOCAL int DeriveResumptionPSK(WOLFSSL* ssl, byte* nonce, byte nonceLen, byte* secret);
 WOLFSSL_LOCAL int DeriveResumptionSecret(WOLFSSL* ssl, byte* key);