1 /*
2  * Copyright (c) 2020-2022 Tracey Emery <tracey@traceyemery.net>
3  * Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
4  * Copyright (c) 2013 Florian Obser <florian@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <arpa/inet.h>
20 #include <sys/queue.h>
21 #include <sys/socket.h>
22 #include <sys/types.h>
23 #include <sys/uio.h>
24 
25 #include <errno.h>
26 #include <event.h>
27 #include <imsg.h>
28 #include <stdarg.h>
29 #include <stdlib.h>
30 #include <stdio.h>
31 #include <string.h>
32 #include <time.h>
33 #include <unistd.h>
34 
35 #include "got_error.h"
36 #include "got_reference.h"
37 
38 #include "proc.h"
39 #include "gotwebd.h"
40 #include "tmpl.h"
41 
42 size_t	 fcgi_parse_record(uint8_t *, size_t, struct request *);
43 void	 fcgi_parse_begin_request(uint8_t *, uint16_t, struct request *,
44 	    uint16_t);
45 void	 fcgi_parse_params(uint8_t *, uint16_t, struct request *, uint16_t);
46 int	 fcgi_send_response(struct request *, int, const void *, size_t);
47 
48 void	 dump_fcgi_record_header(const char *, struct fcgi_record_header *);
49 void	 dump_fcgi_begin_request_body(const char *,
50 	    struct fcgi_begin_request_body *);
51 void	 dump_fcgi_end_request_body(const char *,
52 	    struct fcgi_end_request_body *);
53 
54 extern int	 cgi_inflight;
55 extern volatile int client_cnt;
56 
57 void
58 fcgi_request(int fd, short events, void *arg)
59 {
60 	struct request *c = arg;
61 	ssize_t n;
62 	size_t parsed = 0;
63 
64 	n = read(fd, c->buf + c->buf_pos + c->buf_len,
65 	    FCGI_RECORD_SIZE - c->buf_pos-c->buf_len);
66 
67 	switch (n) {
68 	case -1:
69 		switch (errno) {
70 		case EINTR:
71 		case EAGAIN:
72 			return;
73 		default:
74 			goto fail;
75 		}
76 		break;
77 
78 	case 0:
79 		log_debug("closed connection");
80 		goto fail;
81 	default:
82 		break;
83 	}
84 
85 	c->buf_len += n;
86 
87 	/*
88 	 * Parse the records as they are received. Per the FastCGI
89 	 * specification, the server need only receive the FastCGI
90 	 * parameter records in full; it is free to begin execution
91 	 * at that point, which is what happens here.
92 	 */
93 	do {
94 		parsed = fcgi_parse_record(c->buf + c->buf_pos, c->buf_len, c);
95 		if (parsed != 0) {
96 			c->buf_pos += parsed;
97 			c->buf_len -= parsed;
98 		}
99 
100 		/* drop the parsed record */
101 		if (parsed != 0 && c->buf_len > 0) {
102 			bcopy(c->buf + c->buf_pos, c->buf, c->buf_len);
103 			c->buf_pos = 0;
104 		}
105 	} while (parsed > 0 && c->buf_len > 0);
106 
107 	return;
108 fail:
109 	fcgi_cleanup_request(c);
110 }
111 
112 size_t
113 fcgi_parse_record(uint8_t *buf, size_t n, struct request *c)
114 {
115 	struct fcgi_record_header *h;
116 
117 	if (n < sizeof(struct fcgi_record_header))
118 		 return 0;
119 
120 	h = (struct fcgi_record_header*) buf;
121 
122 	dump_fcgi_record("", h);
123 
124 	if (n < sizeof(struct fcgi_record_header) + ntohs(h->content_len)
125 	    + h->padding_len)
126 		 return 0;
127 
128 	if (h->version != 1)
129 		log_warn("wrong version");
130 
131 	switch (h->type) {
132 	case FCGI_BEGIN_REQUEST:
133 		fcgi_parse_begin_request(buf +
134 		    sizeof(struct fcgi_record_header),
135 		    ntohs(h->content_len), c, ntohs(h->id));
136 		break;
137 	case FCGI_PARAMS:
138 		fcgi_parse_params(buf + sizeof(struct fcgi_record_header),
139 		    ntohs(h->content_len), c, ntohs(h->id));
140 		break;
141 	case FCGI_STDIN:
142 	case FCGI_ABORT_REQUEST:
143 		if (c->sock->client_status != CLIENT_DISCONNECT &&
144 		    c->outbuf_len != 0) {
145 			fcgi_send_response(c, FCGI_STDOUT, c->outbuf,
146 			    c->outbuf_len);
147 		}
148 
149 		fcgi_create_end_record(c);
150 		fcgi_cleanup_request(c);
151 		return 0;
152 	default:
153 		log_warn("unimplemented type %d", h->type);
154 		break;
155 	}
156 
157 	return (sizeof(struct fcgi_record_header) + ntohs(h->content_len)
158 	    + h->padding_len);
159 }
160 
161 void
162 fcgi_parse_begin_request(uint8_t *buf, uint16_t n,
163     struct request *c, uint16_t id)
164 {
165 	/* XXX -- FCGI_CANT_MPX_CONN */
166 	if (c->request_started) {
167 		log_warn("unexpected FCGI_BEGIN_REQUEST, ignoring");
168 		return;
169 	}
170 
171 	if (n != sizeof(struct fcgi_begin_request_body)) {
172 		log_warn("wrong size %d != %lu", n,
173 		    sizeof(struct fcgi_begin_request_body));
174 		return;
175 	}
176 
177 	c->request_started = 1;
178 	c->id = id;
179 }
180 
181 void
182 fcgi_parse_params(uint8_t *buf, uint16_t n, struct request *c, uint16_t id)
183 {
184 	uint32_t name_len, val_len;
185 	uint8_t *val;
186 
187 	if (!c->request_started) {
188 		log_warn("FCGI_PARAMS without FCGI_BEGIN_REQUEST, ignoring");
189 		return;
190 	}
191 
192 	if (c->id != id) {
193 		log_warn("unexpected id, ignoring");
194 		return;
195 	}
196 
197 	if (n == 0) {
198 		gotweb_process_request(c);
199 		return;
200 	}
201 
202 	while (n > 0) {
203 		if (buf[0] >> 7 == 0) {
204 			name_len = buf[0];
205 			n--;
206 			buf++;
207 		} else {
208 			if (n > 3) {
209 				name_len = ((buf[0] & 0x7f) << 24) +
210 				    (buf[1] << 16) + (buf[2] << 8) + buf[3];
211 				n -= 4;
212 				buf += 4;
213 			} else
214 				return;
215 		}
216 
217 		if (n == 0)
218 			return;
219 
220 		if (buf[0] >> 7 == 0) {
221 			val_len = buf[0];
222 			n--;
223 			buf++;
224 		} else {
225 			if (n > 3) {
226 				val_len = ((buf[0] & 0x7f) << 24) +
227 					(buf[1] << 16) + (buf[2] << 8) +
228 					buf[3];
229 				n -= 4;
230 				buf += 4;
231 			} else
232 				return;
233 		}
234 
235 		if (n < name_len + val_len)
236 			return;
237 
238 		val = buf + name_len;
239 
240 		if (c->querystring[0] == '\0' &&
241 		    val_len < MAX_QUERYSTRING &&
242 		    name_len == 12 &&
243 		    strncmp(buf, "QUERY_STRING", 12) == 0) {
244 			memcpy(c->querystring, val, val_len);
245 			c->querystring[val_len] = '\0';
246 		}
247 
248 		if (c->document_uri[0] == '\0' &&
249 		    val_len < MAX_DOCUMENT_URI &&
250 		    name_len == 12 &&
251 		    strncmp(buf, "DOCUMENT_URI", 12) == 0) {
252 			memcpy(c->document_uri, val, val_len);
253 			c->document_uri[val_len] = '\0';
254 		}
255 
256 		if (c->server_name[0] == '\0' &&
257 		    val_len < MAX_SERVER_NAME &&
258 		    name_len == 11 &&
259 		    strncmp(buf, "SERVER_NAME", 11) == 0) {
260 			memcpy(c->server_name, val, val_len);
261 			c->server_name[val_len] = '\0';
262 		}
263 
264 		if (name_len == 5 &&
265 		    strncmp(buf, "HTTPS", 5) == 0)
266 			c->https = 1;
267 
268 		buf += name_len + val_len;
269 		n -= name_len - val_len;
270 	}
271 }
272 
273 void
274 fcgi_timeout(int fd, short events, void *arg)
275 {
276 	fcgi_cleanup_request((struct request*) arg);
277 }
278 
279 int
280 fcgi_puts(struct template *tp, const char *str)
281 {
282 	if (str == NULL)
283 		return 0;
284 	return fcgi_gen_binary_response(tp->tp_arg, str, strlen(str));
285 }
286 
287 int
288 fcgi_putc(struct template *tp, int ch)
289 {
290 	uint8_t c = ch;
291 	return fcgi_gen_binary_response(tp->tp_arg, &c, 1);
292 }
293 
294 int
295 fcgi_vprintf(struct request *c, const char *fmt, va_list ap)
296 {
297 	char *str;
298 	int r;
299 
300 	r = vasprintf(&str, fmt, ap);
301 	if (r == -1) {
302 		log_warn("%s: asprintf", __func__);
303 		return -1;
304 	}
305 
306 	r = fcgi_gen_binary_response(c, str, r);
307 	free(str);
308 	return r;
309 }
310 
311 int
312 fcgi_printf(struct request *c, const char *fmt, ...)
313 {
314 	va_list ap;
315 	int r;
316 
317 	va_start(ap, fmt);
318 	r = fcgi_vprintf(c, fmt, ap);
319 	va_end(ap);
320 
321 	return r;
322 }
323 
324 int
325 fcgi_gen_binary_response(struct request *c, const uint8_t *data, int len)
326 {
327 	int r;
328 
329 	if (c->sock->client_status == CLIENT_DISCONNECT)
330 		return -1;
331 
332 	if (data == NULL || len == 0)
333 		return 0;
334 
335 	/*
336 	 * special case: send big replies -like blobs- directly
337 	 * without copying.
338 	 */
339 	if (len > sizeof(c->outbuf)) {
340 		if (c->outbuf_len > 0) {
341 			fcgi_send_response(c, FCGI_STDOUT,
342 			    c->outbuf, c->outbuf_len);
343 			c->outbuf_len = 0;
344 		}
345 		return fcgi_send_response(c, FCGI_STDOUT, data, len);
346 	}
347 
348 	if (len < sizeof(c->outbuf) - c->outbuf_len) {
349 		memcpy(c->outbuf + c->outbuf_len, data, len);
350 		c->outbuf_len += len;
351 		return 0;
352 	}
353 
354 	r = fcgi_send_response(c, FCGI_STDOUT, c->outbuf, c->outbuf_len);
355 	if (r == -1)
356 		return -1;
357 
358 	memcpy(c->outbuf, data, len);
359 	c->outbuf_len = len;
360 	return 0;
361 }
362 
363 static int
364 send_response(struct request *c, int type, const uint8_t *data,
365     size_t len)
366 {
367 	static const uint8_t padding[FCGI_PADDING_SIZE];
368 	struct fcgi_record_header header;
369 	struct iovec iov[3];
370 	struct timespec ts;
371 	ssize_t nw;
372 	size_t padded_len, tot;
373 	int i, err = 0, th = 2000;
374 
375 	ts.tv_sec = 0;
376 	ts.tv_nsec = 50;
377 
378 	memset(&header, 0, sizeof(header));
379 	header.version = 1;
380 	header.type = type;
381 	header.id = htons(c->id);
382 	header.content_len = htons(len);
383 
384 	/* The FastCGI spec suggests to align the output buffer */
385 	tot = sizeof(header) + len;
386 	padded_len = FCGI_ALIGN(tot);
387 	if (padded_len > tot) {
388 		header.padding_len = padded_len - tot;
389 		tot += header.padding_len;
390 	}
391 
392 	iov[0].iov_base = &header;
393 	iov[0].iov_len = sizeof(header);
394 
395 	iov[1].iov_base = (void *)data;
396 	iov[1].iov_len = len;
397 
398 	iov[2].iov_base = (void *)padding;
399 	iov[2].iov_len = header.padding_len;
400 
401 	dump_fcgi_record("resp ", &header);
402 
403 	/*
404 	 * XXX: add some simple write heuristics here
405 	 * On slower VMs, spotty connections, etc., we don't want to go right to
406 	 * disconnect. Let's at least try to write the data a few times before
407 	 * giving up.
408 	 */
409 	while (tot > 0) {
410 		nw = writev(c->fd, iov, nitems(iov));
411 		if (nw == 0) {
412 			c->sock->client_status = CLIENT_DISCONNECT;
413 			break;
414 		}
415 		if (nw == -1) {
416 			err++;
417 			if (errno == EAGAIN && err < th) {
418 				nanosleep(&ts, NULL);
419 				continue;
420 			}
421 			log_debug("%s: write failure: %s", __func__,
422 			    strerror(errno));
423 			c->sock->client_status = CLIENT_DISCONNECT;
424 			return -1;
425 		}
426 
427 		if (nw != tot)
428 			log_debug("%s: partial write: %zu vs %zu", __func__,
429 			    nw, tot);
430 
431 		tot -= nw;
432 		for (i = 0; i < nitems(iov); ++i) {
433 			if (nw < iov[i].iov_len) {
434 				iov[i].iov_base += nw;
435 				iov[i].iov_len -= nw;
436 				break;
437 			}
438 			nw -= iov[i].iov_len;
439 			iov[i].iov_len = 0;
440 		}
441 	}
442 
443 	return 0;
444 }
445 
446 int
447 fcgi_send_response(struct request *c, int type, const void *data,
448     size_t len)
449 {
450 	if (c->sock->client_status == CLIENT_DISCONNECT)
451 		return -1;
452 
453 	while (len > FCGI_CONTENT_SIZE) {
454 		if (send_response(c, type, data, len) == -1)
455 			return -1;
456 
457 		data += FCGI_CONTENT_SIZE;
458 		len -= FCGI_CONTENT_SIZE;
459 	}
460 
461 	if (len == 0)
462 		return 0;
463 
464 	return send_response(c, type, data, len);
465 }
466 
467 void
468 fcgi_create_end_record(struct request *c)
469 {
470 	struct fcgi_end_request_body end_request;
471 
472 	memset(&end_request, 0, sizeof(end_request));
473 	end_request.app_status = htonl(0); /* script status */
474 	end_request.protocol_status = FCGI_REQUEST_COMPLETE;
475 
476 	fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
477 	    sizeof(end_request));
478 }
479 
480 void
481 fcgi_cleanup_request(struct request *c)
482 {
483 	cgi_inflight--;
484 	client_cnt--;
485 
486 	evtimer_del(&c->tmo);
487 	if (event_initialized(&c->ev))
488 		event_del(&c->ev);
489 
490 	close(c->fd);
491 	template_free(c->tp);
492 	if (c->t != NULL)
493 		gotweb_free_transport(c->t);
494 	free(c);
495 }
496 
497 void
498 dump_fcgi_record(const char *p, struct fcgi_record_header *h)
499 {
500 	dump_fcgi_record_header(p, h);
501 
502 	if (h->type == FCGI_BEGIN_REQUEST)
503 		dump_fcgi_begin_request_body(p,
504 		    (struct fcgi_begin_request_body *)(h + 1));
505 	else if (h->type == FCGI_END_REQUEST)
506 		dump_fcgi_end_request_body(p,
507 		    (struct fcgi_end_request_body *)(h + 1));
508 }
509 
510 void
511 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
512 {
513 	log_debug("%sversion:         %d", p, h->version);
514 	log_debug("%stype:            %d", p, h->type);
515 	log_debug("%srequestId:       %d", p, ntohs(h->id));
516 	log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
517 	log_debug("%spaddingLength:   %d", p, h->padding_len);
518 	log_debug("%sreserved:        %d", p, h->reserved);
519 }
520 
521 void
522 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
523 {
524 	log_debug("%srole             %d", p, ntohs(b->role));
525 	log_debug("%sflags            %d", p, b->flags);
526 }
527 
528 void
529 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
530 {
531 	log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
532 	log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
533 }