server_fcgi.c revision 1.97
1/*	$OpenBSD: server_fcgi.c,v 1.97 2023/11/08 19:19:10 millert Exp $	*/
2
3/*
4 * Copyright (c) 2014 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 <sys/types.h>
20#include <sys/time.h>
21#include <sys/socket.h>
22#include <sys/un.h>
23
24#include <netinet/in.h>
25#include <arpa/inet.h>
26
27#include <limits.h>
28#include <errno.h>
29#include <stdlib.h>
30#include <string.h>
31#include <stdio.h>
32#include <time.h>
33#include <ctype.h>
34#include <event.h>
35#include <unistd.h>
36
37#include "httpd.h"
38#include "http.h"
39
40#define FCGI_PADDING_SIZE	 255
41#define FCGI_RECORD_SIZE	 \
42    (sizeof(struct fcgi_record_header) + FCGI_CONTENT_SIZE + FCGI_PADDING_SIZE)
43
44#define FCGI_BEGIN_REQUEST	 1
45#define FCGI_ABORT_REQUEST	 2
46#define FCGI_END_REQUEST	 3
47#define FCGI_PARAMS		 4
48#define FCGI_STDIN		 5
49#define FCGI_STDOUT		 6
50#define FCGI_STDERR		 7
51#define FCGI_DATA		 8
52#define FCGI_GET_VALUES		 9
53#define FCGI_GET_VALUES_RESULT	10
54#define FCGI_UNKNOWN_TYPE	11
55#define FCGI_MAXTYPE		(FCGI_UNKNOWN_TYPE)
56
57#define FCGI_RESPONDER		 1
58
59struct fcgi_record_header {
60	uint8_t		version;
61	uint8_t		type;
62	uint16_t	id;
63	uint16_t	content_len;
64	uint8_t		padding_len;
65	uint8_t		reserved;
66} __packed;
67
68struct fcgi_begin_request_body {
69	uint16_t	role;
70	uint8_t		flags;
71	uint8_t		reserved[5];
72} __packed;
73
74struct server_fcgi_param {
75	int		total_len;
76	uint8_t		buf[FCGI_RECORD_SIZE];
77};
78
79int	server_fcgi_header(struct client *, unsigned int);
80void	server_fcgi_error(struct bufferevent *, short, void *);
81void	server_fcgi_read(struct bufferevent *, void *);
82int	server_fcgi_writeheader(struct client *, struct kv *, void *);
83int	server_fcgi_writechunk(struct client *);
84int	server_fcgi_getheaders(struct client *);
85int	fcgi_add_param(struct server_fcgi_param *, const char *, const char *,
86	    struct client *);
87
88int
89server_fcgi(struct httpd *env, struct client *clt)
90{
91	struct server_fcgi_param	 param;
92	struct server_config		*srv_conf = clt->clt_srv_conf;
93	struct http_descriptor		*desc = clt->clt_descreq;
94	struct fcgi_record_header	*h;
95	struct fcgi_begin_request_body	*begin;
96	struct fastcgi_param		*fcgiparam;
97	char				 hbuf[HOST_NAME_MAX+1];
98	size_t				 scriptlen;
99	int				 pathlen;
100	int				 fd = -1, ret;
101	const char			*stripped, *alias, *errstr = NULL;
102	char				*query_alias, *str, *script = NULL;
103
104	if ((fd = socket(srv_conf->fastcgi_ss.ss_family,
105	    SOCK_STREAM | SOCK_NONBLOCK, 0)) == -1)
106		goto fail;
107	if ((connect(fd, (struct sockaddr *) &srv_conf->fastcgi_ss,
108	    srv_conf->fastcgi_ss.ss_len)) == -1) {
109		if (errno != EINPROGRESS)
110			goto fail;
111	}
112
113	memset(hbuf, 0, sizeof(hbuf));
114	clt->clt_fcgi.state = FCGI_READ_HEADER;
115	clt->clt_fcgi.toread = sizeof(struct fcgi_record_header);
116	clt->clt_fcgi.status = 200;
117	clt->clt_fcgi.headersdone = 0;
118	clt->clt_fcgi.headerssent = 0;
119
120	if (clt->clt_srvevb != NULL)
121		evbuffer_free(clt->clt_srvevb);
122
123	clt->clt_srvevb = evbuffer_new();
124	if (clt->clt_srvevb == NULL) {
125		errstr = "failed to allocate evbuffer";
126		goto fail;
127	}
128
129	close(clt->clt_fd);
130	clt->clt_fd = fd;
131
132	if (clt->clt_srvbev != NULL)
133		bufferevent_free(clt->clt_srvbev);
134
135	clt->clt_srvbev_throttled = 0;
136	clt->clt_srvbev = bufferevent_new(fd, server_fcgi_read,
137	    NULL, server_fcgi_error, clt);
138	if (clt->clt_srvbev == NULL) {
139		errstr = "failed to allocate fcgi buffer event";
140		goto fail;
141	}
142
143	memset(&param, 0, sizeof(param));
144
145	h = (struct fcgi_record_header *)&param.buf;
146	h->version = 1;
147	h->type = FCGI_BEGIN_REQUEST;
148	h->id = htons(1);
149	h->content_len = htons(sizeof(struct fcgi_begin_request_body));
150	h->padding_len = 0;
151
152	begin = (struct fcgi_begin_request_body *)&param.buf[sizeof(struct
153	    fcgi_record_header)];
154	begin->role = htons(FCGI_RESPONDER);
155
156	if (bufferevent_write(clt->clt_srvbev, &param.buf,
157	    sizeof(struct fcgi_record_header) +
158	    sizeof(struct fcgi_begin_request_body)) == -1) {
159		errstr = "failed to write to evbuffer";
160		goto fail;
161	}
162
163	h->type = FCGI_PARAMS;
164	h->content_len = param.total_len = 0;
165
166	alias = desc->http_path_alias != NULL
167	    ? desc->http_path_alias
168	    : desc->http_path;
169
170	query_alias = desc->http_query_alias != NULL
171	    ? desc->http_query_alias
172	    : desc->http_query;
173
174	stripped = server_root_strip(alias, srv_conf->strip);
175	if ((pathlen = asprintf(&script, "%s%s", srv_conf->root, stripped))
176	    == -1) {
177		errstr = "failed to get script name";
178		goto fail;
179	}
180
181	scriptlen = path_info(script);
182	/*
183	 * no part of root should show up in PATH_INFO.
184	 * therefore scriptlen should be >= strlen(root)
185	 */
186	if (scriptlen < strlen(srv_conf->root))
187		scriptlen = strlen(srv_conf->root);
188	if ((int)scriptlen < pathlen) {
189		if (fcgi_add_param(&param, "PATH_INFO",
190		    script + scriptlen, clt) == -1) {
191			errstr = "failed to encode param";
192			goto fail;
193		}
194		script[scriptlen] = '\0';
195	} else {
196		/* RFC 3875 mandates that PATH_INFO is empty if not set */
197		if (fcgi_add_param(&param, "PATH_INFO", "", clt) == -1) {
198			errstr = "failed to encode param";
199			goto fail;
200		}
201	}
202
203	/*
204	 * calculate length of http SCRIPT_NAME:
205	 * add length of stripped prefix,
206	 * subtract length of prepended local root
207	 */
208	scriptlen += (stripped - alias) - strlen(srv_conf->root);
209	if ((str = strndup(alias, scriptlen)) == NULL)
210		goto fail;
211	ret = fcgi_add_param(&param, "SCRIPT_NAME", str, clt);
212	free(str);
213	if (ret == -1) {
214		errstr = "failed to encode param";
215		goto fail;
216	}
217	if (fcgi_add_param(&param, "SCRIPT_FILENAME", server_root_strip(script,
218	    srv_conf->fcgistrip), clt) == -1) {
219		errstr = "failed to encode param";
220		goto fail;
221	}
222
223	if (query_alias) {
224		if (fcgi_add_param(&param, "QUERY_STRING", query_alias,
225		    clt) == -1) {
226			errstr = "failed to encode param";
227			goto fail;
228		}
229	} else if (fcgi_add_param(&param, "QUERY_STRING", "", clt) == -1) {
230		errstr = "failed to encode param";
231		goto fail;
232	}
233
234	if (fcgi_add_param(&param, "DOCUMENT_ROOT", server_root_strip(
235	    srv_conf->root, srv_conf->fcgistrip), clt) == -1) {
236		errstr = "failed to encode param";
237		goto fail;
238	}
239	if (fcgi_add_param(&param, "DOCUMENT_URI", alias,
240	    clt) == -1) {
241		errstr = "failed to encode param";
242		goto fail;
243	}
244	if (fcgi_add_param(&param, "GATEWAY_INTERFACE", "CGI/1.1",
245	    clt) == -1) {
246		errstr = "failed to encode param";
247		goto fail;
248	}
249
250	if (srv_conf->flags & SRVFLAG_AUTH) {
251		if (fcgi_add_param(&param, "REMOTE_USER",
252		    clt->clt_remote_user, clt) == -1) {
253			errstr = "failed to encode param";
254			goto fail;
255		}
256	}
257
258	/* Add HTTP_* headers */
259	if (server_headers(clt, desc, server_fcgi_writeheader, &param) == -1) {
260		errstr = "failed to encode param";
261		goto fail;
262	}
263
264	if (srv_conf->flags & SRVFLAG_TLS) {
265		if (fcgi_add_param(&param, "HTTPS", "on", clt) == -1) {
266			errstr = "failed to encode param";
267			goto fail;
268		}
269		if (srv_conf->tls_flags != 0 && fcgi_add_param(&param,
270		    "TLS_PEER_VERIFY", printb_flags(srv_conf->tls_flags,
271		    TLSFLAG_BITS), clt) == -1) {
272			errstr = "failed to encode param";
273			goto fail;
274		}
275	}
276
277	TAILQ_FOREACH(fcgiparam, &srv_conf->fcgiparams, entry) {
278		if (fcgi_add_param(&param, fcgiparam->name, fcgiparam->value,
279		    clt) == -1) {
280			errstr = "failed to encode param";
281			goto fail;
282		}
283	}
284
285	(void)print_host(&clt->clt_ss, hbuf, sizeof(hbuf));
286	if (fcgi_add_param(&param, "REMOTE_ADDR", hbuf, clt) == -1) {
287		errstr = "failed to encode param";
288		goto fail;
289	}
290
291	(void)snprintf(hbuf, sizeof(hbuf), "%d", ntohs(clt->clt_port));
292	if (fcgi_add_param(&param, "REMOTE_PORT", hbuf, clt) == -1) {
293		errstr = "failed to encode param";
294		goto fail;
295	}
296
297	if (fcgi_add_param(&param, "REQUEST_METHOD",
298	    server_httpmethod_byid(desc->http_method), clt) == -1) {
299		errstr = "failed to encode param";
300		goto fail;
301	}
302
303	if (!desc->http_query) {
304		if (fcgi_add_param(&param, "REQUEST_URI", desc->http_path_orig,
305		    clt) == -1) {
306			errstr = "failed to encode param";
307			goto fail;
308		}
309	} else {
310		if (asprintf(&str, "%s?%s", desc->http_path_orig,
311		    desc->http_query) == -1) {
312			errstr = "failed to encode param";
313			goto fail;
314		}
315		ret = fcgi_add_param(&param, "REQUEST_URI", str, clt);
316		free(str);
317		if (ret == -1) {
318			errstr = "failed to encode param";
319			goto fail;
320		}
321	}
322
323	(void)print_host(&clt->clt_srv_ss, hbuf, sizeof(hbuf));
324	if (fcgi_add_param(&param, "SERVER_ADDR", hbuf, clt) == -1) {
325		errstr = "failed to encode param";
326		goto fail;
327	}
328
329	(void)snprintf(hbuf, sizeof(hbuf), "%d",
330	    ntohs(server_socket_getport(&clt->clt_srv_ss)));
331	if (fcgi_add_param(&param, "SERVER_PORT", hbuf, clt) == -1) {
332		errstr = "failed to encode param";
333		goto fail;
334	}
335
336	if (fcgi_add_param(&param, "SERVER_NAME", srv_conf->name,
337	    clt) == -1) {
338		errstr = "failed to encode param";
339		goto fail;
340	}
341
342	if (fcgi_add_param(&param, "SERVER_PROTOCOL", desc->http_version,
343	    clt) == -1) {
344		errstr = "failed to encode param";
345		goto fail;
346	}
347
348	if (fcgi_add_param(&param, "SERVER_SOFTWARE", HTTPD_SERVERNAME,
349	    clt) == -1) {
350		errstr = "failed to encode param";
351		goto fail;
352	}
353
354	if (param.total_len != 0) {	/* send last params record */
355		if (bufferevent_write(clt->clt_srvbev, &param.buf,
356		    sizeof(struct fcgi_record_header) +
357		    ntohs(h->content_len)) == -1) {
358			errstr = "failed to write to client evbuffer";
359			goto fail;
360		}
361	}
362
363	/* send "no more params" message */
364	h->content_len = 0;
365	if (bufferevent_write(clt->clt_srvbev, &param.buf,
366	    sizeof(struct fcgi_record_header)) == -1) {
367		errstr = "failed to write to client evbuffer";
368		goto fail;
369	}
370
371	bufferevent_settimeout(clt->clt_srvbev,
372	    srv_conf->timeout.tv_sec, srv_conf->timeout.tv_sec);
373	bufferevent_enable(clt->clt_srvbev, EV_READ|EV_WRITE);
374	if (clt->clt_toread != 0) {
375		/*
376		 * XXX - Work around UAF: server_read_httpcontent() can call
377		 * server_close(), normally freeing clt. If clt->clt_fcgi_count
378		 * reaches 0, call server_close() via server_abort_http().
379		 */
380		clt->clt_fcgi_count++;
381		server_read_httpcontent(clt->clt_bev, clt);
382		if (clt->clt_fcgi_count-- <= 0) {
383			errstr = clt->clt_fcgi_error;
384			goto fail;
385		}
386		bufferevent_enable(clt->clt_bev, EV_READ);
387	} else {
388		bufferevent_disable(clt->clt_bev, EV_READ);
389		fcgi_add_stdin(clt, NULL);
390	}
391
392	if (strcmp(desc->http_version, "HTTP/1.1") == 0) {
393		clt->clt_fcgi.chunked = 1;
394	} else {
395		/* HTTP/1.0 does not support chunked encoding */
396		clt->clt_fcgi.chunked = 0;
397		clt->clt_persist = 0;
398	}
399	clt->clt_fcgi.end = 0;
400	clt->clt_done = 0;
401
402	free(script);
403	return (0);
404 fail:
405	free(script);
406	if (errstr == NULL)
407		errstr = strerror(errno);
408	if (fd != -1 && clt->clt_fd != fd)
409		close(fd);
410	server_abort_http(clt, 500, errstr);
411	return (-1);
412}
413
414int
415fcgi_add_stdin(struct client *clt, struct evbuffer *evbuf)
416{
417	struct fcgi_record_header	h;
418
419	memset(&h, 0, sizeof(h));
420	h.version = 1;
421	h.type = FCGI_STDIN;
422	h.id = htons(1);
423	h.padding_len = 0;
424
425	if (evbuf == NULL) {
426		h.content_len = 0;
427		return bufferevent_write(clt->clt_srvbev, &h,
428		    sizeof(struct fcgi_record_header));
429	} else {
430		h.content_len = htons(EVBUFFER_LENGTH(evbuf));
431		if (bufferevent_write(clt->clt_srvbev, &h,
432		    sizeof(struct fcgi_record_header)) == -1)
433			return -1;
434		return bufferevent_write_buffer(clt->clt_srvbev, evbuf);
435	}
436	return (0);
437}
438
439int
440fcgi_add_param(struct server_fcgi_param *p, const char *key,
441    const char *val, struct client *clt)
442{
443	struct fcgi_record_header	*h;
444	int				 len = 0;
445	int				 key_len = strlen(key);
446	int				 val_len = strlen(val);
447	uint8_t				*param;
448
449	len += key_len + val_len;
450	len += key_len > 127 ? 4 : 1;
451	len += val_len > 127 ? 4 : 1;
452
453	DPRINTF("%s: %s[%d] => %s[%d], total_len: %d", __func__, key, key_len,
454	    val, val_len, p->total_len);
455
456	if (len > FCGI_CONTENT_SIZE)
457		return (-1);
458
459	if (p->total_len + len > FCGI_CONTENT_SIZE) {
460		if (bufferevent_write(clt->clt_srvbev, p->buf,
461		    sizeof(struct fcgi_record_header) + p->total_len) == -1)
462			return (-1);
463		p->total_len = 0;
464	}
465
466	h = (struct fcgi_record_header *)p->buf;
467	param = p->buf + sizeof(*h) + p->total_len;
468
469	if (key_len > 127) {
470		*param++ = ((key_len >> 24) & 0xff) | 0x80;
471		*param++ = ((key_len >> 16) & 0xff);
472		*param++ = ((key_len >> 8) & 0xff);
473		*param++ = (key_len & 0xff);
474	} else
475		*param++ = key_len;
476
477	if (val_len > 127) {
478		*param++ = ((val_len >> 24) & 0xff) | 0x80;
479		*param++ = ((val_len >> 16) & 0xff);
480		*param++ = ((val_len >> 8) & 0xff);
481		*param++ = (val_len & 0xff);
482	} else
483		*param++ = val_len;
484
485	memcpy(param, key, key_len);
486	param += key_len;
487	memcpy(param, val, val_len);
488
489	p->total_len += len;
490
491	h->content_len = htons(p->total_len);
492	return (0);
493}
494
495void
496server_fcgi_error(struct bufferevent *bev, short error, void *arg)
497{
498	struct client		*clt = arg;
499	struct http_descriptor	*desc = clt->clt_descreq;
500
501	if ((error & EVBUFFER_EOF) && !clt->clt_fcgi.headersdone) {
502		server_abort_http(clt, 500, "malformed or no headers");
503		return;
504	}
505
506	/* send the end marker if not already */
507	if (desc->http_method != HTTP_METHOD_HEAD && clt->clt_fcgi.chunked &&
508	    !clt->clt_fcgi.end++)
509		server_bufferevent_print(clt, "0\r\n\r\n");
510
511	server_file_error(bev, error, arg);
512}
513
514void
515server_fcgi_read(struct bufferevent *bev, void *arg)
516{
517	uint8_t				 buf[FCGI_RECORD_SIZE];
518	struct client			*clt = (struct client *) arg;
519	struct fcgi_record_header	*h;
520	size_t				 len;
521	char				*ptr;
522
523	do {
524		len = bufferevent_read(bev, buf, clt->clt_fcgi.toread);
525		if (evbuffer_add(clt->clt_srvevb, buf, len) == -1) {
526			server_abort_http(clt, 500, "short write");
527			return;
528		}
529		clt->clt_fcgi.toread -= len;
530		DPRINTF("%s: len: %lu toread: %d state: %d type: %d",
531		    __func__, len, clt->clt_fcgi.toread,
532		    clt->clt_fcgi.state, clt->clt_fcgi.type);
533
534		if (clt->clt_fcgi.toread != 0)
535			return;
536
537		switch (clt->clt_fcgi.state) {
538		case FCGI_READ_HEADER:
539			clt->clt_fcgi.state = FCGI_READ_CONTENT;
540			h = (struct fcgi_record_header *)
541			    EVBUFFER_DATA(clt->clt_srvevb);
542			DPRINTF("%s: record header: version %d type %d id %d "
543			    "content len %d padding %d", __func__,
544			    h->version, h->type, ntohs(h->id),
545			    ntohs(h->content_len), h->padding_len);
546			clt->clt_fcgi.type = h->type;
547			clt->clt_fcgi.toread = ntohs(h->content_len);
548			clt->clt_fcgi.padding_len = h->padding_len;
549			evbuffer_drain(clt->clt_srvevb,
550			    EVBUFFER_LENGTH(clt->clt_srvevb));
551			if (clt->clt_fcgi.toread != 0)
552				break;
553			else if (clt->clt_fcgi.type == FCGI_STDOUT &&
554			    !clt->clt_chunk) {
555				server_abort_http(clt, 500, "empty stdout");
556				return;
557			}
558
559			/* fallthrough if content_len == 0 */
560		case FCGI_READ_CONTENT:
561			switch (clt->clt_fcgi.type) {
562			case FCGI_STDERR:
563				if (EVBUFFER_LENGTH(clt->clt_srvevb) > 0 &&
564				    (ptr = get_string(
565				    EVBUFFER_DATA(clt->clt_srvevb),
566				    EVBUFFER_LENGTH(clt->clt_srvevb)))
567				    != NULL) {
568					server_sendlog(clt->clt_srv_conf,
569					    IMSG_LOG_ERROR, "%s", ptr);
570					free(ptr);
571				}
572				break;
573			case FCGI_STDOUT:
574				++clt->clt_chunk;
575				if (!clt->clt_fcgi.headersdone) {
576					clt->clt_fcgi.headersdone =
577					    server_fcgi_getheaders(clt);
578					if (!EVBUFFER_LENGTH(clt->clt_srvevb))
579						break;
580				}
581				/* FALLTHROUGH */
582			case FCGI_END_REQUEST:
583				if (clt->clt_fcgi.headersdone &&
584				    !clt->clt_fcgi.headerssent) {
585					if (server_fcgi_header(clt,
586					    clt->clt_fcgi.status) == -1) {
587						server_abort_http(clt, 500,
588						    "malformed fcgi headers");
589						return;
590					}
591				}
592				/* Don't send content for HEAD requests */
593				if (clt->clt_fcgi.headerssent &&
594				    clt->clt_descreq->http_method
595				    == HTTP_METHOD_HEAD)
596					/* nothing */ ;
597				else if (server_fcgi_writechunk(clt) == -1) {
598					server_abort_http(clt, 500,
599					    "encoding error");
600					return;
601				}
602				if (clt->clt_fcgi.type == FCGI_END_REQUEST) {
603					bufferevent_enable(clt->clt_bev,
604					    EV_READ|EV_WRITE);
605					if (clt->clt_persist)
606						clt->clt_toread =
607						    TOREAD_HTTP_HEADER;
608					else
609						clt->clt_toread =
610						    TOREAD_HTTP_NONE;
611					clt->clt_done = 0;
612					server_reset_http(clt);
613				}
614				break;
615			}
616			evbuffer_drain(clt->clt_srvevb,
617			    EVBUFFER_LENGTH(clt->clt_srvevb));
618			if (!clt->clt_fcgi.padding_len) {
619				clt->clt_fcgi.state = FCGI_READ_HEADER;
620				clt->clt_fcgi.toread =
621				    sizeof(struct fcgi_record_header);
622			} else {
623				clt->clt_fcgi.state = FCGI_READ_PADDING;
624				clt->clt_fcgi.toread =
625				    clt->clt_fcgi.padding_len;
626			}
627			break;
628		case FCGI_READ_PADDING:
629			evbuffer_drain(clt->clt_srvevb,
630			    EVBUFFER_LENGTH(clt->clt_srvevb));
631			clt->clt_fcgi.state = FCGI_READ_HEADER;
632			clt->clt_fcgi.toread =
633			    sizeof(struct fcgi_record_header);
634			break;
635		}
636	} while (len > 0);
637}
638
639int
640server_fcgi_header(struct client *clt, unsigned int code)
641{
642	struct server_config	*srv_conf = clt->clt_srv_conf;
643	struct http_descriptor	*desc = clt->clt_descreq;
644	struct http_descriptor	*resp = clt->clt_descresp;
645	const char		*error;
646	char			 tmbuf[32];
647	struct kv		*kv, *cl, key;
648
649	clt->clt_fcgi.headerssent = 1;
650
651	if (desc == NULL || (error = server_httperror_byid(code)) == NULL)
652		return (-1);
653
654	if (server_log_http(clt, code, 0) == -1)
655		return (-1);
656
657	/* Add error codes */
658	if (kv_setkey(&resp->http_pathquery, "%u", code) == -1 ||
659	    kv_set(&resp->http_pathquery, "%s", error) == -1)
660		return (-1);
661
662	/* Add headers */
663	if (kv_add(&resp->http_headers, "Server", HTTPD_SERVERNAME) == NULL)
664		return (-1);
665
666	if (clt->clt_fcgi.type == FCGI_END_REQUEST ||
667	    EVBUFFER_LENGTH(clt->clt_srvevb) == 0) {
668		/* Can't chunk encode an empty body. */
669		clt->clt_fcgi.chunked = 0;
670
671		/* But then we need a Content-Length unless method is HEAD... */
672		if (desc->http_method != HTTP_METHOD_HEAD) {
673			key.kv_key = "Content-Length";
674			if ((kv = kv_find(&resp->http_headers, &key)) == NULL) {
675				if (kv_add(&resp->http_headers,
676				    "Content-Length", "0") == NULL)
677					return (-1);
678			}
679		}
680	}
681
682	/* Send chunked encoding header */
683	if (clt->clt_fcgi.chunked) {
684		/* but only if no Content-Length header is supplied */
685		key.kv_key = "Content-Length";
686		if ((kv = kv_find(&resp->http_headers, &key)) != NULL) {
687			clt->clt_fcgi.chunked = 0;
688		} else {
689			/*
690			 * XXX What if the FastCGI added some kind of
691			 * Transfer-Encoding, like gzip, deflate or even
692			 * "chunked"?
693			 */
694			if (kv_add(&resp->http_headers,
695			    "Transfer-Encoding", "chunked") == NULL)
696				return (-1);
697		}
698	}
699
700	/* Is it a persistent connection? */
701	if (clt->clt_persist) {
702		if (kv_add(&resp->http_headers,
703		    "Connection", "keep-alive") == NULL)
704			return (-1);
705	} else if (kv_add(&resp->http_headers, "Connection", "close") == NULL)
706		return (-1);
707
708	/* HSTS header */
709	if (srv_conf->flags & SRVFLAG_SERVER_HSTS &&
710	    srv_conf->flags & SRVFLAG_TLS) {
711		if ((cl =
712		    kv_add(&resp->http_headers, "Strict-Transport-Security",
713		    NULL)) == NULL ||
714		    kv_set(cl, "max-age=%d%s%s", srv_conf->hsts_max_age,
715		    srv_conf->hsts_flags & HSTSFLAG_SUBDOMAINS ?
716		    "; includeSubDomains" : "",
717		    srv_conf->hsts_flags & HSTSFLAG_PRELOAD ?
718		    "; preload" : "") == -1)
719			return (-1);
720	}
721
722	/* Date header is mandatory and should be added as late as possible */
723	key.kv_key = "Date";
724	if (kv_find(&resp->http_headers, &key) == NULL &&
725	    (server_http_time(time(NULL), tmbuf, sizeof(tmbuf)) <= 0 ||
726	    kv_add(&resp->http_headers, "Date", tmbuf) == NULL))
727		return (-1);
728
729	if (server_writeresponse_http(clt) == -1 ||
730	    server_bufferevent_print(clt, "\r\n") == -1 ||
731	    server_headers(clt, resp, server_writeheader_http, NULL) == -1 ||
732	    server_bufferevent_print(clt, "\r\n") == -1)
733		return (-1);
734
735	return (0);
736}
737
738int
739server_fcgi_writeheader(struct client *clt, struct kv *hdr, void *arg)
740{
741	struct server_fcgi_param	*param = arg;
742	char				*val, *name, *p;
743	const char			*key;
744	int				 ret;
745
746	/* The key might have been updated in the parent */
747	if (hdr->kv_parent != NULL && hdr->kv_parent->kv_key != NULL)
748		key = hdr->kv_parent->kv_key;
749	else
750		key = hdr->kv_key;
751
752	val = hdr->kv_value;
753
754	if (strcasecmp(key, "Content-Length") == 0 ||
755	    strcasecmp(key, "Content-Type") == 0) {
756		if ((name = strdup(key)) == NULL)
757			return (-1);
758	} else {
759		if (asprintf(&name, "HTTP_%s", key) == -1)
760			return (-1);
761	}
762
763	/*
764	 * RFC 7230 defines a header field-name as a "token" and a "token"
765	 * is defined as one or more characters for which isalpha or
766	 * isdigit is true plus a list of additional characters.
767	 * According to RFC 3875 a CGI environment variable is created
768	 * by converting all letters to upper case and replacing '-'
769	 * with '_'.
770	 */
771	for (p = name; *p != '\0'; p++) {
772		if (isalpha((unsigned char)*p))
773			*p = toupper((unsigned char)*p);
774		else if (!(*p == '!' || *p == '#' || *p == '$' || *p == '%' ||
775		    *p == '&' || *p == '\'' || *p == '*' || *p == '+' ||
776		    *p == '.' || *p == '^' || *p == '_' || *p == '`' ||
777		    *p == '|' || *p == '~' || isdigit((unsigned char)*p)))
778			*p = '_';
779	}
780
781	ret = fcgi_add_param(param, name, val, clt);
782	free(name);
783
784	return (ret);
785}
786
787int
788server_fcgi_writechunk(struct client *clt)
789{
790	struct evbuffer *evb = clt->clt_srvevb;
791	size_t		 len;
792
793	if (clt->clt_fcgi.type == FCGI_END_REQUEST) {
794		len = 0;
795	} else
796		len = EVBUFFER_LENGTH(evb);
797
798	if (clt->clt_fcgi.chunked) {
799		/* If len is 0, make sure to write the end marker only once */
800		if (len == 0 && clt->clt_fcgi.end++)
801			return (0);
802		if (server_bufferevent_printf(clt, "%zx\r\n", len) == -1 ||
803		    server_bufferevent_write_chunk(clt, evb, len) == -1 ||
804		    server_bufferevent_print(clt, "\r\n") == -1)
805			return (-1);
806	} else if (len)
807		return (server_bufferevent_write_buffer(clt, evb));
808
809	return (0);
810}
811
812int
813server_fcgi_getheaders(struct client *clt)
814{
815	struct http_descriptor	*resp = clt->clt_descresp;
816	struct evbuffer		*evb = clt->clt_srvevb;
817	int			 code, ret;
818	char			*line, *key, *value;
819	const char		*errstr;
820
821	while ((line = evbuffer_getline(evb)) != NULL && *line != '\0') {
822		key = line;
823
824		if ((value = strchr(key, ':')) == NULL)
825			break;
826
827		*value++ = '\0';
828		value += strspn(value, " \t");
829
830		DPRINTF("%s: %s: %s", __func__, key, value);
831
832		if (strcasecmp("Status", key) == 0) {
833			value[strcspn(value, " \t")] = '\0';
834			code = (int)strtonum(value, 100, 600, &errstr);
835			if (errstr != NULL || server_httperror_byid(
836			    code) == NULL)
837				code = 200;
838			clt->clt_fcgi.status = code;
839		} else {
840			(void)kv_add(&resp->http_headers, key, value);
841		}
842		free(line);
843	}
844
845	ret = (line != NULL && *line == '\0');
846
847	free(line);
848	return ret;
849}
850