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 *sd, *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->http_host[0] == '\0' &&
249 		    val_len < GOTWEBD_MAXTEXT &&
250 		    name_len == 9 &&
251 		    strncmp(buf, "HTTP_HOST", 9) == 0) {
252 			memcpy(c->http_host, val, val_len);
253 			c->http_host[val_len] = '\0';
254 
255 			/*
256 			 * lazily get subdomain
257 			 * will only get domain if no subdomain exists
258 			 * this can still work if gotweb server name is the same
259 			 */
260 			sd = strchr(c->http_host, '.');
261 			if (sd)
262 				*sd = '\0';
263 		}
264 
265 		if (c->document_uri[0] == '\0' &&
266 		    val_len < MAX_DOCUMENT_URI &&
267 		    name_len == 12 &&
268 		    strncmp(buf, "DOCUMENT_URI", 12) == 0) {
269 			memcpy(c->document_uri, val, val_len);
270 			c->document_uri[val_len] = '\0';
271 		}
272 
273 		if (c->server_name[0] == '\0' &&
274 		    val_len < MAX_SERVER_NAME &&
275 		    name_len == 11 &&
276 		    strncmp(buf, "SERVER_NAME", 11) == 0) {
277 			memcpy(c->server_name, val, val_len);
278 			c->server_name[val_len] = '\0';
279 		}
280 
281 		if (name_len == 5 &&
282 		    strncmp(buf, "HTTPS", 5) == 0)
283 			c->https = 1;
284 
285 		buf += name_len + val_len;
286 		n -= name_len - val_len;
287 	}
288 }
289 
290 void
291 fcgi_timeout(int fd, short events, void *arg)
292 {
293 	fcgi_cleanup_request((struct request*) arg);
294 }
295 
296 int
297 fcgi_puts(struct template *tp, const char *str)
298 {
299 	if (str == NULL)
300 		return 0;
301 	return fcgi_gen_binary_response(tp->tp_arg, str, strlen(str));
302 }
303 
304 int
305 fcgi_putc(struct template *tp, int ch)
306 {
307 	uint8_t c = ch;
308 	return fcgi_gen_binary_response(tp->tp_arg, &c, 1);
309 }
310 
311 int
312 fcgi_vprintf(struct request *c, const char *fmt, va_list ap)
313 {
314 	char *str;
315 	int r;
316 
317 	r = vasprintf(&str, fmt, ap);
318 	if (r == -1) {
319 		log_warn("%s: asprintf", __func__);
320 		return -1;
321 	}
322 
323 	r = fcgi_gen_binary_response(c, str, r);
324 	free(str);
325 	return r;
326 }
327 
328 int
329 fcgi_printf(struct request *c, const char *fmt, ...)
330 {
331 	va_list ap;
332 	int r;
333 
334 	va_start(ap, fmt);
335 	r = fcgi_vprintf(c, fmt, ap);
336 	va_end(ap);
337 
338 	return r;
339 }
340 
341 int
342 fcgi_gen_binary_response(struct request *c, const uint8_t *data, int len)
343 {
344 	int r;
345 
346 	if (c->sock->client_status == CLIENT_DISCONNECT)
347 		return -1;
348 
349 	if (data == NULL || len == 0)
350 		return 0;
351 
352 	/*
353 	 * special case: send big replies -like blobs- directly
354 	 * without copying.
355 	 */
356 	if (len > sizeof(c->outbuf)) {
357 		if (c->outbuf_len > 0) {
358 			fcgi_send_response(c, FCGI_STDOUT,
359 			    c->outbuf, c->outbuf_len);
360 			c->outbuf_len = 0;
361 		}
362 		return fcgi_send_response(c, FCGI_STDOUT, data, len);
363 	}
364 
365 	if (len < sizeof(c->outbuf) - c->outbuf_len) {
366 		memcpy(c->outbuf + c->outbuf_len, data, len);
367 		c->outbuf_len += len;
368 		return 0;
369 	}
370 
371 	r = fcgi_send_response(c, FCGI_STDOUT, c->outbuf, c->outbuf_len);
372 	if (r == -1)
373 		return -1;
374 
375 	memcpy(c->outbuf, data, len);
376 	c->outbuf_len = len;
377 	return 0;
378 }
379 
380 static int
381 send_response(struct request *c, int type, const uint8_t *data,
382     size_t len)
383 {
384 	static const uint8_t padding[FCGI_PADDING_SIZE];
385 	struct fcgi_record_header header;
386 	struct iovec iov[3];
387 	struct timespec ts;
388 	ssize_t nw;
389 	size_t padded_len, tot;
390 	int i, err = 0, th = 2000;
391 
392 	ts.tv_sec = 0;
393 	ts.tv_nsec = 50;
394 
395 	memset(&header, 0, sizeof(header));
396 	header.version = 1;
397 	header.type = type;
398 	header.id = htons(c->id);
399 	header.content_len = htons(len);
400 
401 	/* The FastCGI spec suggests to align the output buffer */
402 	tot = sizeof(header) + len;
403 	padded_len = FCGI_ALIGN(tot);
404 	if (padded_len > tot) {
405 		header.padding_len = padded_len - tot;
406 		tot += header.padding_len;
407 	}
408 
409 	iov[0].iov_base = &header;
410 	iov[0].iov_len = sizeof(header);
411 
412 	iov[1].iov_base = (void *)data;
413 	iov[1].iov_len = len;
414 
415 	iov[2].iov_base = (void *)padding;
416 	iov[2].iov_len = header.padding_len;
417 
418 	dump_fcgi_record("resp ", &header);
419 
420 	/*
421 	 * XXX: add some simple write heuristics here
422 	 * On slower VMs, spotty connections, etc., we don't want to go right to
423 	 * disconnect. Let's at least try to write the data a few times before
424 	 * giving up.
425 	 */
426 	while (tot > 0) {
427 		nw = writev(c->fd, iov, nitems(iov));
428 		if (nw == 0) {
429 			c->sock->client_status = CLIENT_DISCONNECT;
430 			break;
431 		}
432 		if (nw == -1) {
433 			err++;
434 			if (errno == EAGAIN && err < th) {
435 				nanosleep(&ts, NULL);
436 				continue;
437 			}
438 			log_debug("%s: write failure: %s", __func__,
439 			    strerror(errno));
440 			c->sock->client_status = CLIENT_DISCONNECT;
441 			return -1;
442 		}
443 
444 		if (nw != tot)
445 			log_debug("%s: partial write: %zu vs %zu", __func__,
446 			    nw, tot);
447 
448 		tot -= nw;
449 		for (i = 0; i < nitems(iov); ++i) {
450 			if (nw < iov[i].iov_len) {
451 				iov[i].iov_base += nw;
452 				iov[i].iov_len -= nw;
453 				break;
454 			}
455 			nw -= iov[i].iov_len;
456 			iov[i].iov_len = 0;
457 		}
458 	}
459 
460 	return 0;
461 }
462 
463 int
464 fcgi_send_response(struct request *c, int type, const void *data,
465     size_t len)
466 {
467 	if (c->sock->client_status == CLIENT_DISCONNECT)
468 		return -1;
469 
470 	while (len > FCGI_CONTENT_SIZE) {
471 		if (send_response(c, type, data, len) == -1)
472 			return -1;
473 
474 		data += FCGI_CONTENT_SIZE;
475 		len -= FCGI_CONTENT_SIZE;
476 	}
477 
478 	if (len == 0)
479 		return 0;
480 
481 	return send_response(c, type, data, len);
482 }
483 
484 void
485 fcgi_create_end_record(struct request *c)
486 {
487 	struct fcgi_end_request_body end_request;
488 
489 	memset(&end_request, 0, sizeof(end_request));
490 	end_request.app_status = htonl(0); /* script status */
491 	end_request.protocol_status = FCGI_REQUEST_COMPLETE;
492 
493 	fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
494 	    sizeof(end_request));
495 }
496 
497 void
498 fcgi_cleanup_request(struct request *c)
499 {
500 	cgi_inflight--;
501 	client_cnt--;
502 
503 	evtimer_del(&c->tmo);
504 	if (event_initialized(&c->ev))
505 		event_del(&c->ev);
506 
507 	close(c->fd);
508 	template_free(c->tp);
509 	if (c->t != NULL)
510 		gotweb_free_transport(c->t);
511 	free(c);
512 }
513 
514 void
515 dump_fcgi_record(const char *p, struct fcgi_record_header *h)
516 {
517 	dump_fcgi_record_header(p, h);
518 
519 	if (h->type == FCGI_BEGIN_REQUEST)
520 		dump_fcgi_begin_request_body(p,
521 		    (struct fcgi_begin_request_body *)(h + 1));
522 	else if (h->type == FCGI_END_REQUEST)
523 		dump_fcgi_end_request_body(p,
524 		    (struct fcgi_end_request_body *)(h + 1));
525 }
526 
527 void
528 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
529 {
530 	log_debug("%sversion:         %d", p, h->version);
531 	log_debug("%stype:            %d", p, h->type);
532 	log_debug("%srequestId:       %d", p, ntohs(h->id));
533 	log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
534 	log_debug("%spaddingLength:   %d", p, h->padding_len);
535 	log_debug("%sreserved:        %d", p, h->reserved);
536 }
537 
538 void
539 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
540 {
541 	log_debug("%srole             %d", p, ntohs(b->role));
542 	log_debug("%sflags            %d", p, b->flags);
543 }
544 
545 void
546 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
547 {
548 	log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
549 	log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
550 }