dgram: fix send with out of bounds offset + length

fix Socket.prototype.send sending garbage when the message is a string,
and offset+length is out of bounds.

Author: Linkgoron

lib/dgram.js

@@ -42,6 +42,7 @@ const { guessHandleType } = internalBinding('util');
 const {
   ERR_INVALID_ARG_TYPE,
   ERR_MISSING_ARGS,
+  ERR_OUT_OF_RANGE,
   ERR_SOCKET_ALREADY_BOUND,
   ERR_SOCKET_BAD_BUFFER_SIZE,
   ERR_SOCKET_BUFFER_SIZE,
@@ -476,6 +477,18 @@ Socket.prototype.sendto = function(buffer,
 function sliceBuffer(buffer, offset, length) {
   if (typeof buffer === 'string') {
     buffer = Buffer.from(buffer);
+    offset = offset >>> 0;
+    length = length >>> 0;
+
+    if (offset > buffer.byteLength) {
+      throw new ERR_OUT_OF_RANGE('offset', `<= ${buffer.byteLength}`, offset);
+    }
+
+    if (offset + length > buffer.byteLength) {
+      throw new ERR_OUT_OF_RANGE('length',
+                                 `<= ${buffer.byteLength - offset}`, length);
+    }
+
   } else if (!isArrayBufferView(buffer)) {
     throw new ERR_INVALID_ARG_TYPE('buffer',
                                    ['Buffer',

test/parallel/test-dgram-send-bad-arguments.js

@@ -77,6 +77,36 @@ function checkArgs(connected) {
         message: 'Already connected'
       }
     );
+
+    assert.throws(
+      () => { sock.send('hello', 6, 0); },
+      {
+        code: 'ERR_OUT_OF_RANGE',
+        name: 'RangeError',
+        message: 'The value of "offset" is out of range. ' +
+        'It must be <= 5. Received 6'
+      }
+    );
+
+    assert.throws(
+      () => { sock.send('hello', 0, 6); },
+      {
+        code: 'ERR_OUT_OF_RANGE',
+        name: 'RangeError',
+        message: 'The value of "length" is out of range. ' +
+        'It must be <= 5. Received 6'
+      }
+    );
+
+    assert.throws(
+      () => { sock.send('hello', 3, 4); },
+      {
+        code: 'ERR_OUT_OF_RANGE',
+        name: 'RangeError',
+        message: 'The value of "length" is out of range. ' +
+        'It must be <= 2. Received 4'
+      }
+    );
   } else {
     assert.throws(() => { sock.send(buf, 1, 1, -1, host); }, RangeError);
     assert.throws(() => { sock.send(buf, 1, 1, 0, host); }, RangeError);