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 "got_compat.h"
20 
21 #include <arpa/inet.h>
22 #include <sys/queue.h>
23 #include <sys/socket.h>
24 #include <sys/types.h>
25 #include <sys/uio.h>
26 
27 #include <errno.h>
28 #include <event.h>
29 #include <imsg.h>
30 #include <stdarg.h>
31 #include <stdlib.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <time.h>
35 #include <unistd.h>
36 
37 #include "got_error.h"
38 #include "got_reference.h"
39 
40 #include "proc.h"
41 #include "gotwebd.h"
42 #include "tmpl.h"
43 
44 size_t	 fcgi_parse_record(uint8_t *, size_t, struct request *);
45 void	 fcgi_parse_begin_request(uint8_t *, uint16_t, struct request *,
46 	    uint16_t);
47 void	 fcgi_parse_params(uint8_t *, uint16_t, struct request *, uint16_t);
48 int	 fcgi_send_response(struct request *, int, const void *, size_t);
49 
50 void	 dump_fcgi_record_header(const char *, struct fcgi_record_header *);
51 void	 dump_fcgi_begin_request_body(const char *,
52 	    struct fcgi_begin_request_body *);
53 void	 dump_fcgi_end_request_body(const char *,
54 	    struct fcgi_end_request_body *);
55 
56 extern int	 cgi_inflight;
57 extern volatile int client_cnt;
58 
59 void
60 fcgi_request(int fd, short events, void *arg)
61 {
62 	struct request *c = arg;
63 	ssize_t n;
64 	size_t parsed = 0;
65 
66 	n = read(fd, c->buf + c->buf_pos + c->buf_len,
67 	    FCGI_RECORD_SIZE - c->buf_pos-c->buf_len);
68 
69 	switch (n) {
70 	case -1:
71 		switch (errno) {
72 		case EINTR:
73 		case EAGAIN:
74 			return;
75 		default:
76 			goto fail;
77 		}
78 		break;
79 
80 	case 0:
81 		log_debug("closed connection");
82 		goto fail;
83 	default:
84 		break;
85 	}
86 
87 	c->buf_len += n;
88 
89 	/*
90 	 * Parse the records as they are received. Per the FastCGI
91 	 * specification, the server need only receive the FastCGI
92 	 * parameter records in full; it is free to begin execution
93 	 * at that point, which is what happens here.
94 	 */
95 	do {
96 		parsed = fcgi_parse_record(c->buf + c->buf_pos, c->buf_len, c);
97 		if (parsed != 0) {
98 			c->buf_pos += parsed;
99 			c->buf_len -= parsed;
100 		}
101 
102 		/* drop the parsed record */
103 		if (parsed != 0 && c->buf_len > 0) {
104 			bcopy(c->buf + c->buf_pos, c->buf, c->buf_len);
105 			c->buf_pos = 0;
106 		}
107 	} while (parsed > 0 && c->buf_len > 0);
108 
109 	return;
110 fail:
111 	fcgi_cleanup_request(c);
112 }
113 
114 size_t
115 fcgi_parse_record(uint8_t *buf, size_t n, struct request *c)
116 {
117 	struct fcgi_record_header *h;
118 
119 	if (n < sizeof(struct fcgi_record_header))
120 		 return 0;
121 
122 	h = (struct fcgi_record_header*) buf;
123 
124 	dump_fcgi_record("", h);
125 
126 	if (n < sizeof(struct fcgi_record_header) + ntohs(h->content_len)
127 	    + h->padding_len)
128 		 return 0;
129 
130 	if (h->version != 1)
131 		log_warn("wrong version");
132 
133 	switch (h->type) {
134 	case FCGI_BEGIN_REQUEST:
135 		fcgi_parse_begin_request(buf +
136 		    sizeof(struct fcgi_record_header),
137 		    ntohs(h->content_len), c, ntohs(h->id));
138 		break;
139 	case FCGI_PARAMS:
140 		fcgi_parse_params(buf + sizeof(struct fcgi_record_header),
141 		    ntohs(h->content_len), c, ntohs(h->id));
142 		break;
143 	case FCGI_STDIN:
144 	case FCGI_ABORT_REQUEST:
145 		if (c->sock->client_status != CLIENT_DISCONNECT &&
146 		    c->outbuf_len != 0) {
147 			fcgi_send_response(c, FCGI_STDOUT, c->outbuf,
148 			    c->outbuf_len);
149 		}
150 
151 		fcgi_create_end_record(c);
152 		fcgi_cleanup_request(c);
153 		return 0;
154 	default:
155 		log_warn("unimplemented type %d", h->type);
156 		break;
157 	}
158 
159 	return (sizeof(struct fcgi_record_header) + ntohs(h->content_len)
160 	    + h->padding_len);
161 }
162 
163 void
164 fcgi_parse_begin_request(uint8_t *buf, uint16_t n,
165     struct request *c, uint16_t id)
166 {
167 	/* XXX -- FCGI_CANT_MPX_CONN */
168 	if (c->request_started) {
169 		log_warn("unexpected FCGI_BEGIN_REQUEST, ignoring");
170 		return;
171 	}
172 
173 	if (n != sizeof(struct fcgi_begin_request_body)) {
174 		log_warn("wrong size %d != %lu", n,
175 		    sizeof(struct fcgi_begin_request_body));
176 		return;
177 	}
178 
179 	c->request_started = 1;
180 	c->id = id;
181 }
182 
183 void
184 fcgi_parse_params(uint8_t *buf, uint16_t n, struct request *c, uint16_t id)
185 {
186 	uint32_t name_len, val_len;
187 	uint8_t *val;
188 
189 	if (!c->request_started) {
190 		log_warn("FCGI_PARAMS without FCGI_BEGIN_REQUEST, ignoring");
191 		return;
192 	}
193 
194 	if (c->id != id) {
195 		log_warn("unexpected id, ignoring");
196 		return;
197 	}
198 
199 	if (n == 0) {
200 		gotweb_process_request(c);
201 		return;
202 	}
203 
204 	while (n > 0) {
205 		if (buf[0] >> 7 == 0) {
206 			name_len = buf[0];
207 			n--;
208 			buf++;
209 		} else {
210 			if (n > 3) {
211 				name_len = ((buf[0] & 0x7f) << 24) +
212 				    (buf[1] << 16) + (buf[2] << 8) + buf[3];
213 				n -= 4;
214 				buf += 4;
215 			} else
216 				return;
217 		}
218 
219 		if (n == 0)
220 			return;
221 
222 		if (buf[0] >> 7 == 0) {
223 			val_len = buf[0];
224 			n--;
225 			buf++;
226 		} else {
227 			if (n > 3) {
228 				val_len = ((buf[0] & 0x7f) << 24) +
229 					(buf[1] << 16) + (buf[2] << 8) +
230 					buf[3];
231 				n -= 4;
232 				buf += 4;
233 			} else
234 				return;
235 		}
236 
237 		if (n < name_len + val_len)
238 			return;
239 
240 		val = buf + name_len;
241 
242 		if (c->querystring[0] == '\0' &&
243 		    val_len < MAX_QUERYSTRING &&
244 		    name_len == 12 &&
245 		    strncmp(buf, "QUERY_STRING", 12) == 0) {
246 			memcpy(c->querystring, val, val_len);
247 			c->querystring[val_len] = '\0';
248 		}
249 
250 		if (c->document_uri[0] == '\0' &&
251 		    val_len < MAX_DOCUMENT_URI &&
252 		    name_len == 12 &&
253 		    strncmp(buf, "DOCUMENT_URI", 12) == 0) {
254 			memcpy(c->document_uri, val, val_len);
255 			c->document_uri[val_len] = '\0';
256 		}
257 
258 		if (c->server_name[0] == '\0' &&
259 		    val_len < MAX_SERVER_NAME &&
260 		    name_len == 11 &&
261 		    strncmp(buf, "SERVER_NAME", 11) == 0) {
262 			memcpy(c->server_name, val, val_len);
263 			c->server_name[val_len] = '\0';
264 		}
265 
266 		if (name_len == 5 &&
267 		    strncmp(buf, "HTTPS", 5) == 0)
268 			c->https = 1;
269 
270 		buf += name_len + val_len;
271 		n -= name_len - val_len;
272 	}
273 }
274 
275 void
276 fcgi_timeout(int fd, short events, void *arg)
277 {
278 	fcgi_cleanup_request((struct request*) arg);
279 }
280 
281 int
282 fcgi_puts(struct template *tp, const char *str)
283 {
284 	if (str == NULL)
285 		return 0;
286 	return fcgi_gen_binary_response(tp->tp_arg, str, strlen(str));
287 }
288 
289 int
290 fcgi_putc(struct template *tp, int ch)
291 {
292 	uint8_t c = ch;
293 	return fcgi_gen_binary_response(tp->tp_arg, &c, 1);
294 }
295 
296 int
297 fcgi_vprintf(struct request *c, const char *fmt, va_list ap)
298 {
299 	char *str;
300 	int r;
301 
302 	r = vasprintf(&str, fmt, ap);
303 	if (r == -1) {
304 		log_warn("%s: asprintf", __func__);
305 		return -1;
306 	}
307 
308 	r = fcgi_gen_binary_response(c, str, r);
309 	free(str);
310 	return r;
311 }
312 
313 int
314 fcgi_printf(struct request *c, const char *fmt, ...)
315 {
316 	va_list ap;
317 	int r;
318 
319 	va_start(ap, fmt);
320 	r = fcgi_vprintf(c, fmt, ap);
321 	va_end(ap);
322 
323 	return r;
324 }
325 
326 int
327 fcgi_gen_binary_response(struct request *c, const uint8_t *data, int len)
328 {
329 	int r;
330 
331 	if (c->sock->client_status == CLIENT_DISCONNECT)
332 		return -1;
333 
334 	if (data == NULL || len == 0)
335 		return 0;
336 
337 	/*
338 	 * special case: send big replies -like blobs- directly
339 	 * without copying.
340 	 */
341 	if (len > sizeof(c->outbuf)) {
342 		if (c->outbuf_len > 0) {
343 			fcgi_send_response(c, FCGI_STDOUT,
344 			    c->outbuf, c->outbuf_len);
345 			c->outbuf_len = 0;
346 		}
347 		return fcgi_send_response(c, FCGI_STDOUT, data, len);
348 	}
349 
350 	if (len < sizeof(c->outbuf) - c->outbuf_len) {
351 		memcpy(c->outbuf + c->outbuf_len, data, len);
352 		c->outbuf_len += len;
353 		return 0;
354 	}
355 
356 	r = fcgi_send_response(c, FCGI_STDOUT, c->outbuf, c->outbuf_len);
357 	if (r == -1)
358 		return -1;
359 
360 	memcpy(c->outbuf, data, len);
361 	c->outbuf_len = len;
362 	return 0;
363 }
364 
365 static int
366 send_response(struct request *c, int type, const uint8_t *data,
367     size_t len)
368 {
369 	static const uint8_t padding[FCGI_PADDING_SIZE];
370 	struct fcgi_record_header header;
371 	struct iovec iov[3];
372 	struct timespec ts;
373 	ssize_t nw;
374 	size_t padded_len, tot;
375 	int i, err = 0, th = 2000;
376 
377 	ts.tv_sec = 0;
378 	ts.tv_nsec = 50;
379 
380 	memset(&header, 0, sizeof(header));
381 	header.version = 1;
382 	header.type = type;
383 	header.id = htons(c->id);
384 	header.content_len = htons(len);
385 
386 	/* The FastCGI spec suggests to align the output buffer */
387 	tot = sizeof(header) + len;
388 	padded_len = FCGI_ALIGN(tot);
389 	if (padded_len > tot) {
390 		header.padding_len = padded_len - tot;
391 		tot += header.padding_len;
392 	}
393 
394 	iov[0].iov_base = &header;
395 	iov[0].iov_len = sizeof(header);
396 
397 	iov[1].iov_base = (void *)data;
398 	iov[1].iov_len = len;
399 
400 	iov[2].iov_base = (void *)padding;
401 	iov[2].iov_len = header.padding_len;
402 
403 	dump_fcgi_record("resp ", &header);
404 
405 	/*
406 	 * XXX: add some simple write heuristics here
407 	 * On slower VMs, spotty connections, etc., we don't want to go right to
408 	 * disconnect. Let's at least try to write the data a few times before
409 	 * giving up.
410 	 */
411 	while (tot > 0) {
412 		nw = writev(c->fd, iov, nitems(iov));
413 		if (nw == 0) {
414 			c->sock->client_status = CLIENT_DISCONNECT;
415 			break;
416 		}
417 		if (nw == -1) {
418 			err++;
419 			if (errno == EAGAIN && err < th) {
420 				nanosleep(&ts, NULL);
421 				continue;
422 			}
423 			log_debug("%s: write failure: %s", __func__,
424 			    strerror(errno));
425 			c->sock->client_status = CLIENT_DISCONNECT;
426 			return -1;
427 		}
428 
429 		if (nw != tot)
430 			log_debug("%s: partial write: %zu vs %zu", __func__,
431 			    nw, tot);
432 
433 		tot -= nw;
434 		for (i = 0; i < nitems(iov); ++i) {
435 			if (nw < iov[i].iov_len) {
436 				iov[i].iov_base += nw;
437 				iov[i].iov_len -= nw;
438 				break;
439 			}
440 			nw -= iov[i].iov_len;
441 			iov[i].iov_len = 0;
442 		}
443 	}
444 
445 	return 0;
446 }
447 
448 int
449 fcgi_send_response(struct request *c, int type, const void *data,
450     size_t len)
451 {
452 	if (c->sock->client_status == CLIENT_DISCONNECT)
453 		return -1;
454 
455 	while (len > FCGI_CONTENT_SIZE) {
456 		if (send_response(c, type, data, len) == -1)
457 			return -1;
458 
459 		data += FCGI_CONTENT_SIZE;
460 		len -= FCGI_CONTENT_SIZE;
461 	}
462 
463 	if (len == 0)
464 		return 0;
465 
466 	return send_response(c, type, data, len);
467 }
468 
469 void
470 fcgi_create_end_record(struct request *c)
471 {
472 	struct fcgi_end_request_body end_request;
473 
474 	memset(&end_request, 0, sizeof(end_request));
475 	end_request.app_status = htonl(0); /* script status */
476 	end_request.protocol_status = FCGI_REQUEST_COMPLETE;
477 
478 	fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
479 	    sizeof(end_request));
480 }
481 
482 void
483 fcgi_cleanup_request(struct request *c)
484 {
485 	cgi_inflight--;
486 	client_cnt--;
487 
488 	evtimer_del(&c->tmo);
489 	if (event_initialized(&c->ev))
490 		event_del(&c->ev);
491 
492 	close(c->fd);
493 	template_free(c->tp);
494 	if (c->t != NULL)
495 		gotweb_free_transport(c->t);
496 	free(c);
497 }
498 
499 void
500 dump_fcgi_record(const char *p, struct fcgi_record_header *h)
501 {
502 	dump_fcgi_record_header(p, h);
503 
504 	if (h->type == FCGI_BEGIN_REQUEST)
505 		dump_fcgi_begin_request_body(p,
506 		    (struct fcgi_begin_request_body *)(h + 1));
507 	else if (h->type == FCGI_END_REQUEST)
508 		dump_fcgi_end_request_body(p,
509 		    (struct fcgi_end_request_body *)(h + 1));
510 }
511 
512 void
513 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
514 {
515 	log_debug("%sversion:         %d", p, h->version);
516 	log_debug("%stype:            %d", p, h->type);
517 	log_debug("%srequestId:       %d", p, ntohs(h->id));
518 	log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
519 	log_debug("%spaddingLength:   %d", p, h->padding_len);
520 	log_debug("%sreserved:        %d", p, h->reserved);
521 }
522 
523 void
524 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
525 {
526 	log_debug("%srole             %d", p, ntohs(b->role));
527 	log_debug("%sflags            %d", p, b->flags);
528 }
529 
530 void
531 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
532 {
533 	log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
534 	log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
535 }