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 		fcgi_create_end_record(c);
146 		fcgi_cleanup_request(c);
147 		return 0;
148 	default:
149 		log_warn("unimplemented type %d", h->type);
150 		break;
151 	}
152 
153 	return (sizeof(struct fcgi_record_header) + ntohs(h->content_len)
154 	    + h->padding_len);
155 }
156 
157 void
158 fcgi_parse_begin_request(uint8_t *buf, uint16_t n,
159     struct request *c, uint16_t id)
160 {
161 	/* XXX -- FCGI_CANT_MPX_CONN */
162 	if (c->request_started) {
163 		log_warn("unexpected FCGI_BEGIN_REQUEST, ignoring");
164 		return;
165 	}
166 
167 	if (n != sizeof(struct fcgi_begin_request_body)) {
168 		log_warn("wrong size %d != %lu", n,
169 		    sizeof(struct fcgi_begin_request_body));
170 		return;
171 	}
172 
173 	c->request_started = 1;
174 	c->id = id;
175 }
176 
177 void
178 fcgi_parse_params(uint8_t *buf, uint16_t n, struct request *c, uint16_t id)
179 {
180 	uint32_t name_len, val_len;
181 	uint8_t *val;
182 
183 	if (!c->request_started) {
184 		log_warn("FCGI_PARAMS without FCGI_BEGIN_REQUEST, ignoring");
185 		return;
186 	}
187 
188 	if (c->id != id) {
189 		log_warn("unexpected id, ignoring");
190 		return;
191 	}
192 
193 	if (n == 0) {
194 		gotweb_process_request(c);
195 		template_flush(c->tp);
196 		return;
197 	}
198 
199 	while (n > 0) {
200 		if (buf[0] >> 7 == 0) {
201 			name_len = buf[0];
202 			n--;
203 			buf++;
204 		} else {
205 			if (n > 3) {
206 				name_len = ((buf[0] & 0x7f) << 24) +
207 				    (buf[1] << 16) + (buf[2] << 8) + buf[3];
208 				n -= 4;
209 				buf += 4;
210 			} else
211 				return;
212 		}
213 
214 		if (n == 0)
215 			return;
216 
217 		if (buf[0] >> 7 == 0) {
218 			val_len = buf[0];
219 			n--;
220 			buf++;
221 		} else {
222 			if (n > 3) {
223 				val_len = ((buf[0] & 0x7f) << 24) +
224 					(buf[1] << 16) + (buf[2] << 8) +
225 					buf[3];
226 				n -= 4;
227 				buf += 4;
228 			} else
229 				return;
230 		}
231 
232 		if (n < name_len + val_len)
233 			return;
234 
235 		val = buf + name_len;
236 
237 		if (c->querystring[0] == '\0' &&
238 		    val_len < MAX_QUERYSTRING &&
239 		    name_len == 12 &&
240 		    strncmp(buf, "QUERY_STRING", 12) == 0) {
241 			memcpy(c->querystring, val, val_len);
242 			c->querystring[val_len] = '\0';
243 		}
244 
245 		if (c->document_uri[0] == '\0' &&
246 		    val_len < MAX_DOCUMENT_URI &&
247 		    name_len == 12 &&
248 		    strncmp(buf, "DOCUMENT_URI", 12) == 0) {
249 			memcpy(c->document_uri, val, val_len);
250 			c->document_uri[val_len] = '\0';
251 		}
252 
253 		if (c->server_name[0] == '\0' &&
254 		    val_len < MAX_SERVER_NAME &&
255 		    name_len == 11 &&
256 		    strncmp(buf, "SERVER_NAME", 11) == 0) {
257 			memcpy(c->server_name, val, val_len);
258 			c->server_name[val_len] = '\0';
259 		}
260 
261 		if (name_len == 5 &&
262 		    strncmp(buf, "HTTPS", 5) == 0)
263 			c->https = 1;
264 
265 		buf += name_len + val_len;
266 		n -= name_len - val_len;
267 	}
268 }
269 
270 void
271 fcgi_timeout(int fd, short events, void *arg)
272 {
273 	fcgi_cleanup_request((struct request*) arg);
274 }
275 
276 static int
277 send_response(struct request *c, int type, const uint8_t *data,
278     size_t len)
279 {
280 	static const uint8_t padding[FCGI_PADDING_SIZE];
281 	struct fcgi_record_header header;
282 	struct iovec iov[3];
283 	struct timespec ts;
284 	ssize_t nw;
285 	size_t padded_len, tot;
286 	int i, err = 0, th = 2000;
287 
288 	ts.tv_sec = 0;
289 	ts.tv_nsec = 50;
290 
291 	memset(&header, 0, sizeof(header));
292 	header.version = 1;
293 	header.type = type;
294 	header.id = htons(c->id);
295 	header.content_len = htons(len);
296 
297 	/* The FastCGI spec suggests to align the output buffer */
298 	tot = sizeof(header) + len;
299 	padded_len = FCGI_ALIGN(tot);
300 	if (padded_len > tot) {
301 		header.padding_len = padded_len - tot;
302 		tot += header.padding_len;
303 	}
304 
305 	iov[0].iov_base = &header;
306 	iov[0].iov_len = sizeof(header);
307 
308 	iov[1].iov_base = (void *)data;
309 	iov[1].iov_len = len;
310 
311 	iov[2].iov_base = (void *)padding;
312 	iov[2].iov_len = header.padding_len;
313 
314 	dump_fcgi_record("resp ", &header);
315 
316 	/*
317 	 * XXX: add some simple write heuristics here
318 	 * On slower VMs, spotty connections, etc., we don't want to go right to
319 	 * disconnect. Let's at least try to write the data a few times before
320 	 * giving up.
321 	 */
322 	while (tot > 0) {
323 		nw = writev(c->fd, iov, nitems(iov));
324 		if (nw == 0) {
325 			c->sock->client_status = CLIENT_DISCONNECT;
326 			break;
327 		}
328 		if (nw == -1) {
329 			err++;
330 			if (errno == EAGAIN && err < th) {
331 				nanosleep(&ts, NULL);
332 				continue;
333 			}
334 			log_debug("%s: write failure: %s", __func__,
335 			    strerror(errno));
336 			c->sock->client_status = CLIENT_DISCONNECT;
337 			return -1;
338 		}
339 
340 		if (nw != tot)
341 			log_debug("%s: partial write: %zu vs %zu", __func__,
342 			    nw, tot);
343 
344 		tot -= nw;
345 		for (i = 0; i < nitems(iov); ++i) {
346 			if (nw < iov[i].iov_len) {
347 				iov[i].iov_base += nw;
348 				iov[i].iov_len -= nw;
349 				break;
350 			}
351 			nw -= iov[i].iov_len;
352 			iov[i].iov_len = 0;
353 		}
354 	}
355 
356 	return 0;
357 }
358 
359 int
360 fcgi_send_response(struct request *c, int type, const void *data,
361     size_t len)
362 {
363 	if (c->sock->client_status == CLIENT_DISCONNECT)
364 		return -1;
365 
366 	while (len > FCGI_CONTENT_SIZE) {
367 		if (send_response(c, type, data, len) == -1)
368 			return -1;
369 
370 		data += FCGI_CONTENT_SIZE;
371 		len -= FCGI_CONTENT_SIZE;
372 	}
373 
374 	if (len == 0)
375 		return 0;
376 
377 	return send_response(c, type, data, len);
378 }
379 
380 int
381 fcgi_write(void *arg, const void *buf, size_t len)
382 {
383 	struct request	*c = arg;
384 
385 	return fcgi_send_response(c, FCGI_STDOUT, buf, len);
386 }
387 
388 void
389 fcgi_create_end_record(struct request *c)
390 {
391 	struct fcgi_end_request_body end_request;
392 
393 	memset(&end_request, 0, sizeof(end_request));
394 	end_request.app_status = htonl(0); /* script status */
395 	end_request.protocol_status = FCGI_REQUEST_COMPLETE;
396 
397 	fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
398 	    sizeof(end_request));
399 }
400 
401 void
402 fcgi_cleanup_request(struct request *c)
403 {
404 	cgi_inflight--;
405 	client_cnt--;
406 
407 	evtimer_del(&c->tmo);
408 	if (event_initialized(&c->ev))
409 		event_del(&c->ev);
410 
411 	close(c->fd);
412 	template_free(c->tp);
413 	if (c->t != NULL)
414 		gotweb_free_transport(c->t);
415 	free(c);
416 }
417 
418 void
419 dump_fcgi_record(const char *p, struct fcgi_record_header *h)
420 {
421 	dump_fcgi_record_header(p, h);
422 
423 	if (h->type == FCGI_BEGIN_REQUEST)
424 		dump_fcgi_begin_request_body(p,
425 		    (struct fcgi_begin_request_body *)(h + 1));
426 	else if (h->type == FCGI_END_REQUEST)
427 		dump_fcgi_end_request_body(p,
428 		    (struct fcgi_end_request_body *)(h + 1));
429 }
430 
431 void
432 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
433 {
434 	log_debug("%sversion:         %d", p, h->version);
435 	log_debug("%stype:            %d", p, h->type);
436 	log_debug("%srequestId:       %d", p, ntohs(h->id));
437 	log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
438 	log_debug("%spaddingLength:   %d", p, h->padding_len);
439 	log_debug("%sreserved:        %d", p, h->reserved);
440 }
441 
442 void
443 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
444 {
445 	log_debug("%srole             %d", p, ntohs(b->role));
446 	log_debug("%sflags            %d", p, b->flags);
447 }
448 
449 void
450 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
451 {
452 	log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
453 	log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
454 }