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Date:: Tue Dec 20 17:46:23 2022 UTC
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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 
37 #include "proc.h"
38 #include "gotwebd.h"
39 #include "tmpl.h"
40 
41 size_t	 fcgi_parse_record(uint8_t *, size_t, struct request *);
42 void	 fcgi_parse_begin_request(uint8_t *, uint16_t, struct request *,
43 	    uint16_t);
44 void	 fcgi_parse_params(uint8_t *, uint16_t, struct request *, uint16_t);
45 int	 fcgi_send_response(struct request *, int, const void *, size_t);
46 
47 void	 dump_fcgi_record_header(const char *, struct fcgi_record_header *);
48 void	 dump_fcgi_begin_request_body(const char *,
49 	    struct fcgi_begin_request_body *);
50 void	 dump_fcgi_end_request_body(const char *,
51 	    struct fcgi_end_request_body *);
52 
53 extern int	 cgi_inflight;
54 extern volatile int client_cnt;
55 
56 void
57 fcgi_request(int fd, short events, void *arg)
58 {
59 	struct request *c = arg;
60 	ssize_t n;
61 	size_t parsed = 0;
62 
63 	n = read(fd, c->buf + c->buf_pos + c->buf_len,
64 	    FCGI_RECORD_SIZE - c->buf_pos-c->buf_len);
65 
66 	switch (n) {
67 	case -1:
68 		switch (errno) {
69 		case EINTR:
70 		case EAGAIN:
71 			return;
72 		default:
73 			goto fail;
74 		}
75 		break;
76 
77 	case 0:
78 		log_debug("closed connection");
79 		goto fail;
80 	default:
81 		break;
82 	}
83 
84 	c->buf_len += n;
85 
86 	/*
87 	 * Parse the records as they are received. Per the FastCGI
88 	 * specification, the server need only receive the FastCGI
89 	 * parameter records in full; it is free to begin execution
90 	 * at that point, which is what happens here.
91 	 */
92 	do {
93 		parsed = fcgi_parse_record(c->buf + c->buf_pos, c->buf_len, c);
94 		if (parsed != 0) {
95 			c->buf_pos += parsed;
96 			c->buf_len -= parsed;
97 		}
98 	} while (parsed > 0 && c->buf_len > 0);
99 
100 	/* Make space for further reads */
101 	if (parsed != 0)
102 		if (c->buf_len > 0) {
103 			bcopy(c->buf + c->buf_pos, c->buf, c->buf_len);
104 			c->buf_pos = 0;
105 		}
106 	return;
107 fail:
108 	fcgi_cleanup_request(c);
109 }
110 
111 size_t
112 fcgi_parse_record(uint8_t *buf, size_t n, struct request *c)
113 {
114 	struct fcgi_record_header *h;
115 
116 	if (n < sizeof(struct fcgi_record_header))
117 		 return 0;
118 
119 	h = (struct fcgi_record_header*) buf;
120 
121 	dump_fcgi_record("", h);
122 
123 	if (n < sizeof(struct fcgi_record_header) + ntohs(h->content_len)
124 	    + h->padding_len)
125 		 return 0;
126 
127 	if (h->version != 1)
128 		log_warn("wrong version");
129 
130 	switch (h->type) {
131 	case FCGI_BEGIN_REQUEST:
132 		fcgi_parse_begin_request(buf +
133 		    sizeof(struct fcgi_record_header),
134 		    ntohs(h->content_len), c, ntohs(h->id));
135 		break;
136 	case FCGI_PARAMS:
137 		fcgi_parse_params(buf + sizeof(struct fcgi_record_header),
138 		    ntohs(h->content_len), c, ntohs(h->id));
139 		break;
140 	case FCGI_STDIN:
141 	case FCGI_ABORT_REQUEST:
142 		if (c->sock->client_status != CLIENT_DISCONNECT &&
143 		    c->outbuf_len != 0) {
144 			fcgi_send_response(c, FCGI_STDOUT, c->outbuf,
145 			    c->outbuf_len);
146 		}
147 
148 		fcgi_create_end_record(c);
149 		fcgi_cleanup_request(c);
150 		return 0;
151 	default:
152 		log_warn("unimplemented type %d", h->type);
153 		break;
154 	}
155 
156 	return (sizeof(struct fcgi_record_header) + ntohs(h->content_len)
157 	    + h->padding_len);
158 }
159 
160 void
161 fcgi_parse_begin_request(uint8_t *buf, uint16_t n,
162     struct request *c, uint16_t id)
163 {
164 	/* XXX -- FCGI_CANT_MPX_CONN */
165 	if (c->request_started) {
166 		log_warn("unexpected FCGI_BEGIN_REQUEST, ignoring");
167 		return;
168 	}
169 
170 	if (n != sizeof(struct fcgi_begin_request_body)) {
171 		log_warn("wrong size %d != %lu", n,
172 		    sizeof(struct fcgi_begin_request_body));
173 		return;
174 	}
175 
176 	c->request_started = 1;
177 	c->id = id;
178 }
179 
180 void
181 fcgi_parse_params(uint8_t *buf, uint16_t n, struct request *c, uint16_t id)
182 {
183 	uint32_t name_len, val_len;
184 	uint8_t *sd, *val;
185 
186 	if (!c->request_started) {
187 		log_warn("FCGI_PARAMS without FCGI_BEGIN_REQUEST, ignoring");
188 		return;
189 	}
190 
191 	if (c->id != id) {
192 		log_warn("unexpected id, ignoring");
193 		return;
194 	}
195 
196 	if (n == 0) {
197 		gotweb_process_request(c);
198 		return;
199 	}
200 
201 	while (n > 0) {
202 		if (buf[0] >> 7 == 0) {
203 			name_len = buf[0];
204 			n--;
205 			buf++;
206 		} else {
207 			if (n > 3) {
208 				name_len = ((buf[0] & 0x7f) << 24) +
209 				    (buf[1] << 16) + (buf[2] << 8) + buf[3];
210 				n -= 4;
211 				buf += 4;
212 			} else
213 				return;
214 		}
215 
216 		if (n == 0)
217 			return;
218 
219 		if (buf[0] >> 7 == 0) {
220 			val_len = buf[0];
221 			n--;
222 			buf++;
223 		} else {
224 			if (n > 3) {
225 				val_len = ((buf[0] & 0x7f) << 24) +
226 					(buf[1] << 16) + (buf[2] << 8) +
227 					buf[3];
228 				n -= 4;
229 				buf += 4;
230 			} else
231 				return;
232 		}
233 
234 		if (n < name_len + val_len)
235 			return;
236 
237 		val = buf + name_len;
238 
239 		if (c->querystring[0] == '\0' &&
240 		    val_len < MAX_QUERYSTRING &&
241 		    name_len == 12 &&
242 		    strncmp(buf, "QUERY_STRING", 12) == 0) {
243 			memcpy(c->querystring, val, val_len);
244 			c->querystring[val_len] = '\0';
245 		}
246 
247 		if (c->http_host[0] == '\0' &&
248 		    val_len < GOTWEBD_MAXTEXT &&
249 		    name_len == 9 &&
250 		    strncmp(buf, "HTTP_HOST", 9) == 0) {
251 			memcpy(c->http_host, val, val_len);
252 			c->http_host[val_len] = '\0';
253 
254 			/*
255 			 * lazily get subdomain
256 			 * will only get domain if no subdomain exists
257 			 * this can still work if gotweb server name is the same
258 			 */
259 			sd = strchr(c->http_host, '.');
260 			if (sd)
261 				*sd = '\0';
262 		}
263 
264 		if (c->document_uri[0] == '\0' &&
265 		    val_len < MAX_DOCUMENT_URI &&
266 		    name_len == 12 &&
267 		    strncmp(buf, "DOCUMENT_URI", 12) == 0) {
268 			memcpy(c->document_uri, val, val_len);
269 			c->document_uri[val_len] = '\0';
270 		}
271 
272 		if (c->server_name[0] == '\0' &&
273 		    val_len < MAX_SERVER_NAME &&
274 		    name_len == 11 &&
275 		    strncmp(buf, "SERVER_NAME", 11) == 0) {
276 			memcpy(c->server_name, val, val_len);
277 			c->server_name[val_len] = '\0';
278 		}
279 
280 		if (name_len == 5 &&
281 		    strncmp(buf, "HTTPS", 5) == 0)
282 			c->https = 1;
283 
284 		buf += name_len + val_len;
285 		n -= name_len - val_len;
286 	}
287 }
288 
289 void
290 fcgi_timeout(int fd, short events, void *arg)
291 {
292 	fcgi_cleanup_request((struct request*) arg);
293 }
294 
295 int
296 fcgi_puts(struct template *tp, const char *str)
297 {
298 	if (str == NULL)
299 		return 0;
300 	return fcgi_gen_binary_response(tp->tp_arg, str, strlen(str));
301 }
302 
303 int
304 fcgi_putc(struct template *tp, int ch)
305 {
306 	uint8_t c = ch;
307 	return fcgi_gen_binary_response(tp->tp_arg, &c, 1);
308 }
309 
310 int
311 fcgi_vprintf(struct request *c, const char *fmt, va_list ap)
312 {
313 	char *str;
314 	int r;
315 
316 	r = vasprintf(&str, fmt, ap);
317 	if (r == -1) {
318 		log_warn("%s: asprintf", __func__);
319 		return -1;
320 	}
321 
322 	r = fcgi_gen_binary_response(c, str, r);
323 	free(str);
324 	return r;
325 }
326 
327 int
328 fcgi_printf(struct request *c, const char *fmt, ...)
329 {
330 	va_list ap;
331 	int r;
332 
333 	va_start(ap, fmt);
334 	r = fcgi_vprintf(c, fmt, ap);
335 	va_end(ap);
336 
337 	return r;
338 }
339 
340 int
341 fcgi_gen_binary_response(struct request *c, const uint8_t *data, int len)
342 {
343 	int r;
344 
345 	if (c->sock->client_status == CLIENT_DISCONNECT)
346 		return -1;
347 
348 	if (data == NULL || len == 0)
349 		return 0;
350 
351 	/*
352 	 * special case: send big replies -like blobs- directly
353 	 * without copying.
354 	 */
355 	if (len > sizeof(c->outbuf)) {
356 		if (c->outbuf_len > 0) {
357 			fcgi_send_response(c, FCGI_STDOUT,
358 			    c->outbuf, c->outbuf_len);
359 			c->outbuf_len = 0;
360 		}
361 		return fcgi_send_response(c, FCGI_STDOUT, data, len);
362 	}
363 
364 	if (len < sizeof(c->outbuf) - c->outbuf_len) {
365 		memcpy(c->outbuf + c->outbuf_len, data, len);
366 		c->outbuf_len += len;
367 		return 0;
368 	}
369 
370 	r = fcgi_send_response(c, FCGI_STDOUT, c->outbuf, c->outbuf_len);
371 	if (r == -1)
372 		return -1;
373 
374 	memcpy(c->outbuf, data, len);
375 	c->outbuf_len = len;
376 	return 0;
377 }
378 
379 static int
380 send_response(struct request *c, int type, const uint8_t *data,
381     size_t len)
382 {
383 	static const uint8_t padding[FCGI_PADDING_SIZE];
384 	struct fcgi_record_header header;
385 	struct iovec iov[3];
386 	struct timespec ts;
387 	ssize_t nw;
388 	size_t padded_len, tot;
389 	int i, err = 0, th = 2000;
390 
391 	ts.tv_sec = 0;
392 	ts.tv_nsec = 50;
393 
394 	memset(&header, 0, sizeof(header));
395 	header.version = 1;
396 	header.type = type;
397 	header.id = htons(c->id);
398 	header.content_len = htons(len);
399 
400 	/* The FastCGI spec suggests to align the output buffer */
401 	tot = sizeof(header) + len;
402 	padded_len = FCGI_ALIGN(tot);
403 	if (padded_len > tot) {
404 		header.padding_len = padded_len - tot;
405 		tot += header.padding_len;
406 	}
407 
408 	iov[0].iov_base = &header;
409 	iov[0].iov_len = sizeof(header);
410 
411 	iov[1].iov_base = (void *)data;
412 	iov[1].iov_len = len;
413 
414 	iov[2].iov_base = (void *)padding;
415 	iov[2].iov_len = header.padding_len;
416 
417 	dump_fcgi_record("resp ", &header);
418 
419 	/*
420 	 * XXX: add some simple write heuristics here
421 	 * On slower VMs, spotty connections, etc., we don't want to go right to
422 	 * disconnect. Let's at least try to write the data a few times before
423 	 * giving up.
424 	 */
425 	while (tot > 0) {
426 		nw = writev(c->fd, iov, nitems(iov));
427 		if (nw == 0) {
428 			c->sock->client_status = CLIENT_DISCONNECT;
429 			break;
430 		}
431 		if (nw == -1) {
432 			err++;
433 			if (errno == EAGAIN && err < th) {
434 				nanosleep(&ts, NULL);
435 				continue;
436 			}
437 			log_warn("%s: write failure", __func__);
438 			c->sock->client_status = CLIENT_DISCONNECT;
439 			return -1;
440 		}
441 
442 		if (nw != tot)
443 			log_debug("%s: partial write: %zu vs %zu", __func__,
444 			    nw, tot);
445 
446 		tot -= nw;
447 		for (i = 0; i < nitems(iov); ++i) {
448 			if (nw < iov[i].iov_len) {
449 				iov[i].iov_base += nw;
450 				iov[i].iov_len -= nw;
451 				break;
452 			}
453 			nw -= iov[i].iov_len;
454 			iov[i].iov_len = 0;
455 		}
456 	}
457 
458 	return 0;
459 }
460 
461 int
462 fcgi_send_response(struct request *c, int type, const void *data,
463     size_t len)
464 {
465 	if (c->sock->client_status == CLIENT_DISCONNECT)
466 		return -1;
467 
468 	while (len > FCGI_CONTENT_SIZE) {
469 		if (send_response(c, type, data, len) == -1)
470 			return -1;
471 
472 		data += FCGI_CONTENT_SIZE;
473 		len -= FCGI_CONTENT_SIZE;
474 	}
475 
476 	if (len == 0)
477 		return 0;
478 
479 	return send_response(c, type, data, len);
480 }
481 
482 void
483 fcgi_create_end_record(struct request *c)
484 {
485 	struct fcgi_end_request_body end_request;
486 
487 	memset(&end_request, 0, sizeof(end_request));
488 	end_request.app_status = htonl(0); /* script status */
489 	end_request.protocol_status = FCGI_REQUEST_COMPLETE;
490 
491 	fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
492 	    sizeof(end_request));
493 }
494 
495 void
496 fcgi_cleanup_request(struct request *c)
497 {
498 	cgi_inflight--;
499 	client_cnt--;
500 
501 	evtimer_del(&c->tmo);
502 	if (event_initialized(&c->ev))
503 		event_del(&c->ev);
504 
505 	close(c->fd);
506 	template_free(c->tp);
507 	gotweb_free_transport(c->t);
508 	free(c);
509 }
510 
511 void
512 dump_fcgi_record(const char *p, struct fcgi_record_header *h)
513 {
514 	dump_fcgi_record_header(p, h);
515 
516 	if (h->type == FCGI_BEGIN_REQUEST)
517 		dump_fcgi_begin_request_body(p,
518 		    (struct fcgi_begin_request_body *)(h + 1));
519 	else if (h->type == FCGI_END_REQUEST)
520 		dump_fcgi_end_request_body(p,
521 		    (struct fcgi_end_request_body *)(h + 1));
522 }
523 
524 void
525 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
526 {
527 	log_debug("%sversion:         %d", p, h->version);
528 	log_debug("%stype:            %d", p, h->type);
529 	log_debug("%srequestId:       %d", p, ntohs(h->id));
530 	log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
531 	log_debug("%spaddingLength:   %d", p, h->padding_len);
532 	log_debug("%sreserved:        %d", p, h->reserved);
533 }
534 
535 void
536 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
537 {
538 	log_debug("%srole             %d", p, ntohs(b->role));
539 	log_debug("%sflags            %d", p, b->flags);
540 }
541 
542 void
543 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
544 {
545 	log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
546 	log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
547 }