TooLong: refuse too long messages.

Author: kareltucek

device/src/messenger.c

@@ -443,6 +443,16 @@ int Messenger_SendMessage(message_t* message) {
     connection_id_t connectionId = message->connectionId;
     device_id_t dst = message->dst;
 
+    uint16_t totalLen = 3 + message->idsUsed + message->len;
+    if (totalLen > MAX_LINK_PACKET_LENGTH) {
+        const char *desc1, *desc2;
+        getMessageDescription(message->messageId[0], message->messageId[1], &desc1, &desc2);
+        LogU("Refusing to send over-long message (%d > %d bytes) to %s: %s %s\n",
+            totalLen, MAX_LINK_PACKET_LENGTH, Utils_DeviceIdToString(dst),
+            desc1 == NULL ? "" : desc1, desc2 == NULL ? "" : desc2);
+        return -1;
+    }
+
     int err = 0;
 
     switch (connectionId) {

shared/uart_parser.c

@@ -23,9 +23,10 @@ static void appendRxByte(uart_parser_t *uartState, uint8_t byte) {
         uartState->rxCrcBuffer[uartState->rxPosition++] = byte;
     } else if (uartState->rxPosition - CRC_LEN < uartState->rxLength) {
         uartState->rxBuffer[uartState->rxPosition++ - CRC_LEN] = byte;
-    } else {
-        LogU("Uart error: too long message [%i, %i, ... %i]\n", uartState->rxPosition, uartState->rxBuffer[0], uartState->rxBuffer[1], byte);
-        uartState->receiveMessage(uartState, UartControl_Unexpected, NULL, 0);
+    } else if (!uartState->rxTooLong) {
+        uartState->rxTooLong = true;
+        LogU("Uart error: too long message, discarding [len %i: src %i, dst %i, msgId %i, propId %i]\n",
+            uartState->rxLength, uartState->rxBuffer[0], uartState->rxBuffer[1], uartState->rxBuffer[3], uartState->rxBuffer[4]);
     }
 }
 
@@ -95,6 +96,11 @@ static void processIncomingByte(uart_parser_t *uartState, uint8_t byte) {
 
                 uartState->receivingMessage = false;
 
+                if (uartState->rxTooLong) {
+                    uartState->rxTooLong = false;
+                    break;
+                }
+
                 uint16_t len = uartState->rxPosition;
                 uint8_t* data = uartState->rxBuffer;
 
@@ -117,6 +123,7 @@ static void processIncomingByte(uart_parser_t *uartState, uint8_t byte) {
             }
             uartState->receivingMessage = true;
             uartState->rxPosition = 0;
+            uartState->rxTooLong = false;
             break;
 msg_byte:
         default:
@@ -209,6 +216,7 @@ void UartParser_InitParser(
     uartState->txPosition = 0;
     uartState->receivingMessage = false;
     uartState->escaping = false;
+    uartState->rxTooLong = false;
     uartState->receiveMessage = receiveMessage;
     uartState->userArg = userArg;
 }
@@ -219,6 +227,7 @@ void UartParser_SetRxBuffer(uart_parser_t *uartState, uint8_t* buffer, uint16_t
     uartState->rxLength = length;
     uartState->escaping = false;
     uartState->receivingMessage = false;
+    uartState->rxTooLong = false;
 }
 
 void UartParser_SetTxBuffer(uart_parser_t *uartState, uint8_t* buffer, uint16_t length) {

shared/uart_parser.h

@@ -47,6 +47,7 @@
 
         bool escaping;
         bool receivingMessage;
+        bool rxTooLong;
 
     } uart_parser_t;