ForceZero mac buffer in DoTls13Finished before return F-1464

Author: julek-wolfssl

src/tls13.c

@@ -11346,28 +11346,30 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
             ret = NO_PEER_CERT; /* NO_PEER_VERIFY */
             WOLFSSL_MSG("TLS v1.3 client did not present peer cert");
             DoCertFatalAlert(ssl, ret);
-            return ret;
+            goto cleanup;
         }
     }
 #endif
 
     /* check against totalSz */
-    if (*inOutIdx + size > totalSz)
-        return BUFFER_E;
+    if (*inOutIdx + size > totalSz) {
+        ret = BUFFER_E;
+        goto cleanup;
+    }
 
 #if defined(WOLFSSL_RENESAS_TSIP_TLS)
     ret = tsip_Tls13HandleFinished(ssl, input, inOutIdx, size, totalSz);
     if (ret == 0) {
         ssl->options.serverState = SERVER_FINISHED_COMPLETE;
-        return ret;
+        goto cleanup;
     }
     if (ret == WC_NO_ERR_TRACE(VERIFY_FINISHED_ERROR)) {
         SendAlert(ssl, alert_fatal, decrypt_error);
-        return ret;
+        goto cleanup;
     }
     if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
         /* other errors */
-        return ret;
+        goto cleanup;
     }
     ret = 0;
 #endif /* WOLFSSL_RENESAS_TSIP_TLS */
@@ -11377,7 +11379,7 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                                    ssl->keys.client_write_MAC_secret,
                                    WOLFSSL_CLIENT_END);
         if (ret != 0)
-            return ret;
+            goto cleanup;
 
         secret = ssl->keys.client_write_MAC_secret;
     }
@@ -11389,13 +11391,13 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                                    ssl->keys.client_write_MAC_secret,
                                    WOLFSSL_CLIENT_END);
         if (ret != 0)
-            return ret;
+            goto cleanup;
 
         ret = DeriveFinishedSecret(ssl, ssl->serverSecret,
                                    ssl->keys.server_write_MAC_secret,
                                    WOLFSSL_SERVER_END);
         if (ret != 0)
-            return ret;
+            goto cleanup;
 
         secret = ssl->keys.server_write_MAC_secret;
     }
@@ -11408,7 +11410,8 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
         ret = BuildTls13HandshakeHmac(ssl, secret, mac, &finishedSz);
     #ifdef WOLFSSL_HAVE_TLS_UNIQUE
         if (finishedSz > TLS_FINISHED_SZ_MAX) {
-            return BUFFER_ERROR;
+            ret = BUFFER_ERROR;
+            goto cleanup;
         }
         if (ssl->options.side == WOLFSSL_CLIENT_END) {
             XMEMCPY(ssl->serverFinished, mac, finishedSz);
@@ -11420,9 +11423,11 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
         }
     #endif /* WOLFSSL_HAVE_TLS_UNIQUE */
         if (ret != 0)
-            return ret;
-        if (size != finishedSz)
-            return BUFFER_ERROR;
+            goto cleanup;
+        if (size != finishedSz) {
+            ret = BUFFER_ERROR;
+            goto cleanup;
+        }
     }
 
 #ifdef WOLFSSL_CALLBACKS
@@ -11437,7 +11442,8 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
             WOLFSSL_MSG("Verify finished error on hashes");
             SendAlert(ssl, alert_fatal, decrypt_error);
             WOLFSSL_ERROR_VERBOSE(VERIFY_FINISHED_ERROR);
-            return VERIFY_FINISHED_ERROR;
+            ret = VERIFY_FINISHED_ERROR;
+            goto cleanup;
         }
     }
 
@@ -11450,12 +11456,12 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
 #ifdef WOLFSSL_EARLY_DATA
         if (ssl->earlyData != no_early_data) {
             if ((ret = DeriveTls13Keys(ssl, no_key, DECRYPT_SIDE_ONLY, 1)) != 0)
-                return ret;
+                goto cleanup;
         }
 #endif
         /* Setup keys for application data messages from client. */
         if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
-            return ret;
+            goto cleanup;
     }
 #endif
 
@@ -11486,10 +11492,13 @@ int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
     }
 #endif /* WOLFSSL_QUIC && WOLFSSL_EARLY_DATA */
 
-    WOLFSSL_LEAVE("DoTls13Finished", 0);
+    ret = 0;
+cleanup:
+    ForceZero(mac, sizeof(mac));
+    WOLFSSL_LEAVE("DoTls13Finished", ret);
     WOLFSSL_END(WC_FUNC_FINISHED_DO);
 
-    return 0;
+    return ret;
 }
 
 #if !defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER)