1/* Copyright JS Foundation and other contributors, http://js.foundation
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16#include "debugger-sha1.h"
17#include "jerryscript-ext/debugger.h"
18#include "jext-common.h"
19
20#if defined (JERRY_DEBUGGER) && (JERRY_DEBUGGER == 1)
21
22/* JerryScript debugger protocol is a simplified version of RFC-6455 (WebSockets). */
23
24/**
25 * Last fragment of a Websocket package.
26 */
27#define JERRYX_DEBUGGER_WEBSOCKET_FIN_BIT 0x80
28
29/**
30 * Masking-key is available.
31 */
32#define JERRYX_DEBUGGER_WEBSOCKET_MASK_BIT 0x80
33
34/**
35 * Opcode type mask.
36 */
37#define JERRYX_DEBUGGER_WEBSOCKET_OPCODE_MASK 0x0fu
38
39/**
40 * Packet length mask.
41 */
42#define JERRYX_DEBUGGER_WEBSOCKET_LENGTH_MASK 0x7fu
43
44/**
45 * Size of websocket header size.
46 */
47#define JERRYX_DEBUGGER_WEBSOCKET_HEADER_SIZE 2
48
49/**
50 * Payload mask size in bytes of a websocket package.
51 */
52#define JERRYX_DEBUGGER_WEBSOCKET_MASK_SIZE 4
53
54/**
55 * Maximum message size with 1 byte size field.
56 */
57#define JERRYX_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX 125
58
59/**
60 * WebSocket opcode types.
61 */
62typedef enum
63{
64  JERRYX_DEBUGGER_WEBSOCKET_TEXT_FRAME = 1, /**< text frame */
65  JERRYX_DEBUGGER_WEBSOCKET_BINARY_FRAME = 2, /**< binary frame */
66  JERRYX_DEBUGGER_WEBSOCKET_CLOSE_CONNECTION = 8, /**< close connection */
67  JERRYX_DEBUGGER_WEBSOCKET_PING = 9, /**< ping (keep alive) frame */
68  JERRYX_DEBUGGER_WEBSOCKET_PONG = 10, /**< reply to ping frame */
69} jerryx_websocket_opcode_type_t;
70
71/**
72 * Header for incoming packets.
73 */
74typedef struct
75{
76  uint8_t ws_opcode; /**< websocket opcode */
77  uint8_t size; /**< size of the message */
78  uint8_t mask[4]; /**< mask bytes */
79} jerryx_websocket_receive_header_t;
80
81/**
82 * Convert a 6-bit value to a Base64 character.
83 *
84 * @return Base64 character
85 */
86static uint8_t
87jerryx_to_base64_character (uint8_t value) /**< 6-bit value */
88{
89  if (value < 26)
90  {
91    return (uint8_t) (value + 'A');
92  }
93
94  if (value < 52)
95  {
96    return (uint8_t) (value - 26 + 'a');
97  }
98
99  if (value < 62)
100  {
101    return (uint8_t) (value - 52 + '0');
102  }
103
104  if (value == 62)
105  {
106    return (uint8_t) '+';
107  }
108
109  return (uint8_t) '/';
110} /* jerryx_to_base64_character */
111
112/**
113 * Encode a byte sequence into Base64 string.
114 */
115static void
116jerryx_to_base64 (const uint8_t *source_p, /**< source data */
117                 uint8_t *destination_p, /**< destination buffer */
118                 size_t length) /**< length of source, must be divisible by 3 */
119{
120  while (length >= 3)
121  {
122    uint8_t value = (source_p[0] >> 2);
123    destination_p[0] = jerryx_to_base64_character (value);
124
125    value = (uint8_t) (((source_p[0] << 4) | (source_p[1] >> 4)) & 0x3f);
126    destination_p[1] = jerryx_to_base64_character (value);
127
128    value = (uint8_t) (((source_p[1] << 2) | (source_p[2] >> 6)) & 0x3f);
129    destination_p[2] = jerryx_to_base64_character (value);
130
131    value = (uint8_t) (source_p[2] & 0x3f);
132    destination_p[3] = jerryx_to_base64_character (value);
133
134    source_p += 3;
135    destination_p += 4;
136    length -= 3;
137  }
138} /* jerryx_to_base64 */
139
140/**
141 * Process WebSocket handshake.
142 *
143 * @return true - if the handshake was completed successfully
144 *         false - otherwise
145 */
146static bool
147jerryx_process_handshake (uint8_t *request_buffer_p) /**< temporary buffer */
148{
149  size_t request_buffer_size = 1024;
150  uint8_t *request_end_p = request_buffer_p;
151
152  /* Buffer request text until the double newlines are received. */
153  while (true)
154  {
155    jerry_debugger_transport_receive_context_t context;
156    if (!jerry_debugger_transport_receive (&context))
157    {
158      JERRYX_ASSERT (!jerry_debugger_transport_is_connected ());
159      return false;
160    }
161
162    if (context.message_p == NULL)
163    {
164      jerry_debugger_transport_sleep ();
165      continue;
166    }
167
168    size_t length = request_buffer_size - 1u - (size_t) (request_end_p - request_buffer_p);
169
170    if (length < context.message_length)
171    {
172      JERRYX_ERROR_MSG ("Handshake buffer too small.\n");
173      return false;
174    }
175
176    /* Both stream and datagram packets are supported. */
177    memcpy (request_end_p, context.message_p, context.message_length);
178
179    jerry_debugger_transport_receive_completed (&context);
180
181    request_end_p += (size_t) context.message_length;
182    *request_end_p = 0;
183
184    if (request_end_p > request_buffer_p + 4
185        && memcmp (request_end_p - 4, "\r\n\r\n", 4) == 0)
186    {
187      break;
188    }
189  }
190
191  /* Check protocol. */
192  const char get_text[] = "GET /jerry-debugger";
193  size_t text_len = sizeof (get_text) - 1;
194
195  if ((size_t) (request_end_p - request_buffer_p) < text_len
196      || memcmp (request_buffer_p, get_text, text_len) != 0)
197  {
198    JERRYX_ERROR_MSG ("Invalid handshake format.\n");
199    return false;
200  }
201
202  uint8_t *websocket_key_p = request_buffer_p + text_len;
203
204  const char key_text[] = "Sec-WebSocket-Key:";
205  text_len = sizeof (key_text) - 1;
206
207  while (true)
208  {
209    if ((size_t) (request_end_p - websocket_key_p) < text_len)
210    {
211      JERRYX_ERROR_MSG ("Sec-WebSocket-Key not found.\n");
212      return false;
213    }
214
215    if (websocket_key_p[0] == 'S'
216        && websocket_key_p[-1] == '\n'
217        && websocket_key_p[-2] == '\r'
218        && memcmp (websocket_key_p, key_text, text_len) == 0)
219    {
220      websocket_key_p += text_len;
221      break;
222    }
223
224    websocket_key_p++;
225  }
226
227  /* String terminated by double newlines. */
228
229  while (*websocket_key_p == ' ')
230  {
231    websocket_key_p++;
232  }
233
234  uint8_t *websocket_key_end_p = websocket_key_p;
235
236  while (*websocket_key_end_p > ' ')
237  {
238    websocket_key_end_p++;
239  }
240
241  /* Since the request_buffer_p is not needed anymore it can
242   * be reused for storing the SHA-1 key and Base64 string. */
243
244  const size_t sha1_length = 20;
245
246  jerryx_debugger_compute_sha1 (websocket_key_p,
247                               (size_t) (websocket_key_end_p - websocket_key_p),
248                               (const uint8_t *) "258EAFA5-E914-47DA-95CA-C5AB0DC85B11",
249                               36,
250                               request_buffer_p);
251
252  /* The SHA-1 key is 20 bytes long but jerryx_to_base64 expects
253   * a length divisible by 3 so an extra 0 is appended at the end. */
254  request_buffer_p[sha1_length] = 0;
255
256  jerryx_to_base64 (request_buffer_p, request_buffer_p + sha1_length + 1, sha1_length + 1);
257
258  /* Last value must be replaced by equal sign. */
259
260  const uint8_t response_prefix[] =
261  "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: ";
262
263  if (!jerry_debugger_transport_send (response_prefix, sizeof (response_prefix) - 1)
264      || !jerry_debugger_transport_send (request_buffer_p + sha1_length + 1, 27))
265  {
266    return false;
267  }
268
269  const uint8_t response_suffix[] = "=\r\n\r\n";
270  return jerry_debugger_transport_send (response_suffix, sizeof (response_suffix) - 1);
271} /* jerryx_process_handshake */
272
273/**
274 * Close a tcp connection.
275 */
276static void
277jerryx_debugger_ws_close (jerry_debugger_transport_header_t *header_p) /**< tcp implementation */
278{
279  JERRYX_ASSERT (!jerry_debugger_transport_is_connected ());
280
281  jerry_heap_free ((void *) header_p, sizeof (jerry_debugger_transport_header_t));
282} /* jerryx_debugger_ws_close */
283
284/**
285 * Send data over a websocket connection.
286 *
287 * @return true - if the data has been sent successfully
288 *         false - otherwise
289 */
290static bool
291jerryx_debugger_ws_send (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
292                         uint8_t *message_p, /**< message to be sent */
293                         size_t message_length) /**< message length in bytes */
294{
295  JERRYX_ASSERT (message_length <= JERRYX_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
296
297  message_p[-2] = JERRYX_DEBUGGER_WEBSOCKET_FIN_BIT | JERRYX_DEBUGGER_WEBSOCKET_BINARY_FRAME;
298  message_p[-1] = (uint8_t) message_length;
299
300  return header_p->next_p->send (header_p->next_p, message_p - 2, message_length + 2);
301} /* jerryx_debugger_ws_send */
302
303/**
304 * Receive data from a websocket connection.
305 */
306static bool
307jerryx_debugger_ws_receive (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
308                            jerry_debugger_transport_receive_context_t *receive_context_p) /**< receive context */
309{
310  if (!header_p->next_p->receive (header_p->next_p, receive_context_p))
311  {
312    return false;
313  }
314
315  if (receive_context_p->message_p == NULL)
316  {
317    return true;
318  }
319
320  size_t message_total_length = receive_context_p->message_total_length;
321
322  if (message_total_length == 0)
323  {
324    /* Byte stream. */
325    if (receive_context_p->message_length < sizeof (jerryx_websocket_receive_header_t))
326    {
327      receive_context_p->message_p = NULL;
328      return true;
329    }
330  }
331  else
332  {
333    /* Datagram packet. */
334    JERRYX_ASSERT (receive_context_p->message_length >= sizeof (jerryx_websocket_receive_header_t));
335  }
336
337  uint8_t *message_p = receive_context_p->message_p;
338
339  if ((message_p[0] & ~JERRYX_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRYX_DEBUGGER_WEBSOCKET_FIN_BIT
340      || (message_p[1] & JERRYX_DEBUGGER_WEBSOCKET_LENGTH_MASK) > JERRYX_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX
341      || !(message_p[1] & JERRYX_DEBUGGER_WEBSOCKET_MASK_BIT))
342  {
343    JERRYX_ERROR_MSG ("Unsupported Websocket message.\n");
344    jerry_debugger_transport_close ();
345    return false;
346  }
347
348  if ((message_p[0] & JERRYX_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRYX_DEBUGGER_WEBSOCKET_BINARY_FRAME)
349  {
350    JERRYX_ERROR_MSG ("Unsupported Websocket opcode.\n");
351    jerry_debugger_transport_close ();
352    return false;
353  }
354
355  size_t message_length = (size_t) (message_p[1] & JERRYX_DEBUGGER_WEBSOCKET_LENGTH_MASK);
356
357  if (message_total_length == 0)
358  {
359    size_t new_total_length = message_length + sizeof (jerryx_websocket_receive_header_t);
360
361    /* Byte stream. */
362    if (receive_context_p->message_length < new_total_length)
363    {
364      receive_context_p->message_p = NULL;
365      return true;
366    }
367
368    receive_context_p->message_total_length = new_total_length;
369  }
370  else
371  {
372    /* Datagram packet. */
373    JERRYX_ASSERT (receive_context_p->message_length == (message_length + sizeof (jerryx_websocket_receive_header_t)));
374  }
375
376  message_p += sizeof (jerryx_websocket_receive_header_t);
377
378  receive_context_p->message_p = message_p;
379  receive_context_p->message_length = message_length;
380
381  /* Unmask data bytes. */
382  const uint8_t *mask_p = message_p - JERRYX_DEBUGGER_WEBSOCKET_MASK_SIZE;
383  const uint8_t *mask_end_p = message_p;
384  const uint8_t *message_end_p = message_p + message_length;
385
386  while (message_p < message_end_p)
387  {
388    /* Invert certain bits with xor operation. */
389    *message_p = *message_p ^ *mask_p;
390
391    message_p++;
392    mask_p++;
393
394    if (JERRY_UNLIKELY (mask_p >= mask_end_p))
395    {
396      mask_p -= JERRYX_DEBUGGER_WEBSOCKET_MASK_SIZE;
397    }
398  }
399
400  return true;
401} /* jerryx_debugger_ws_receive */
402
403/**
404 * Initialize the websocket transportation layer.
405 *
406 * @return true - if the connection succeeded
407 *         false - otherwise
408 */
409bool
410jerryx_debugger_ws_create (void)
411{
412  bool is_handshake_ok = false;
413
414  const size_t buffer_size = 1024;
415  uint8_t *request_buffer_p = (uint8_t *) jerry_heap_alloc (buffer_size);
416
417  if (!request_buffer_p)
418  {
419    return false;
420  }
421
422  is_handshake_ok = jerryx_process_handshake (request_buffer_p);
423
424  jerry_heap_free ((void *) request_buffer_p, buffer_size);
425
426  if (!is_handshake_ok && jerry_debugger_transport_is_connected ())
427  {
428    return false;
429  }
430
431  const size_t interface_size = sizeof (jerry_debugger_transport_header_t);
432  jerry_debugger_transport_header_t *header_p;
433  header_p = (jerry_debugger_transport_header_t *) jerry_heap_alloc (interface_size);
434
435  if (!header_p)
436  {
437    return false;
438  }
439
440  header_p->close = jerryx_debugger_ws_close;
441  header_p->send = jerryx_debugger_ws_send;
442  header_p->receive = jerryx_debugger_ws_receive;
443
444  jerry_debugger_transport_add (header_p,
445                                JERRYX_DEBUGGER_WEBSOCKET_HEADER_SIZE,
446                                JERRYX_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX,
447                                JERRYX_DEBUGGER_WEBSOCKET_HEADER_SIZE + JERRYX_DEBUGGER_WEBSOCKET_MASK_SIZE,
448                                JERRYX_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
449
450  return true;
451} /* jerryx_debugger_ws_create */
452
453#else /* !(defined (JERRY_DEBUGGER) && (JERRY_DEBUGGER == 1)) */
454
455/**
456 * Dummy function when debugger is disabled.
457 *
458 * @return false
459 */
460bool
461jerryx_debugger_ws_create (void)
462{
463  return false;
464} /* jerryx_debugger_ws_create */
465
466#endif /* defined (JERRY_DEBUGGER) && (JERRY_DEBUGGER == 1) */
467