1 881a9dd9 2021-01-16 op /*
  2 881a9dd9 2021-01-16 op  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
  3 881a9dd9 2021-01-16 op  *
  4 881a9dd9 2021-01-16 op  * Permission to use, copy, modify, and distribute this software for any
  5 881a9dd9 2021-01-16 op  * purpose with or without fee is hereby granted, provided that the above
  6 881a9dd9 2021-01-16 op  * copyright notice and this permission notice appear in all copies.
  7 881a9dd9 2021-01-16 op  *
  8 881a9dd9 2021-01-16 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 881a9dd9 2021-01-16 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 881a9dd9 2021-01-16 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 881a9dd9 2021-01-16 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 881a9dd9 2021-01-16 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 881a9dd9 2021-01-16 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 881a9dd9 2021-01-16 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 881a9dd9 2021-01-16 op  */
 16 881a9dd9 2021-01-16 op 
 17 881a9dd9 2021-01-16 op #include <err.h>
 18 881a9dd9 2021-01-16 op #include <errno.h>
 19 881a9dd9 2021-01-16 op 
 20 881a9dd9 2021-01-16 op #include <fcntl.h>
 21 881a9dd9 2021-01-16 op #include <signal.h>
 22 881a9dd9 2021-01-16 op #include <string.h>
 23 881a9dd9 2021-01-16 op 
 24 881a9dd9 2021-01-16 op #include "gmid.h"
 25 881a9dd9 2021-01-16 op 
 26 881a9dd9 2021-01-16 op int
 27 881a9dd9 2021-01-16 op send_string(int fd, const char *str)
 28 881a9dd9 2021-01-16 op {
 29 881a9dd9 2021-01-16 op 	ssize_t len;
 30 881a9dd9 2021-01-16 op 
 31 881a9dd9 2021-01-16 op 	if (str == NULL)
 32 881a9dd9 2021-01-16 op 		len = 0;
 33 881a9dd9 2021-01-16 op 	else
 34 881a9dd9 2021-01-16 op 		len = strlen(str);
 35 881a9dd9 2021-01-16 op 
 36 881a9dd9 2021-01-16 op 	if (write(fd, &len, sizeof(len)) != sizeof(len))
 37 881a9dd9 2021-01-16 op 		return 0;
 38 881a9dd9 2021-01-16 op 
 39 881a9dd9 2021-01-16 op 	if (len != 0)
 40 881a9dd9 2021-01-16 op 		if (write(fd, str, len) != len)
 41 881a9dd9 2021-01-16 op 			return 0;
 42 881a9dd9 2021-01-16 op 
 43 881a9dd9 2021-01-16 op 	return 1;
 44 881a9dd9 2021-01-16 op }
 45 881a9dd9 2021-01-16 op 
 46 881a9dd9 2021-01-16 op int
 47 881a9dd9 2021-01-16 op recv_string(int fd, char **ret)
 48 881a9dd9 2021-01-16 op {
 49 881a9dd9 2021-01-16 op 	ssize_t len;
 50 881a9dd9 2021-01-16 op 
 51 881a9dd9 2021-01-16 op 	if (read(fd, &len, sizeof(len)) != sizeof(len))
 52 881a9dd9 2021-01-16 op 		return 0;
 53 881a9dd9 2021-01-16 op 
 54 881a9dd9 2021-01-16 op 	if (len == 0) {
 55 881a9dd9 2021-01-16 op 		*ret = NULL;
 56 881a9dd9 2021-01-16 op 		return 1;
 57 881a9dd9 2021-01-16 op 	}
 58 881a9dd9 2021-01-16 op 
 59 881a9dd9 2021-01-16 op 	if ((*ret = calloc(1, len+1)) == NULL)
 60 881a9dd9 2021-01-16 op 		return 0;
 61 881a9dd9 2021-01-16 op 
 62 881a9dd9 2021-01-16 op 	if (read(fd, *ret, len) != len)
 63 881a9dd9 2021-01-16 op 		return 0;
 64 881a9dd9 2021-01-16 op 	return 1;
 65 881a9dd9 2021-01-16 op }
 66 881a9dd9 2021-01-16 op 
 67 881a9dd9 2021-01-16 op int
 68 881a9dd9 2021-01-16 op send_vhost(int fd, struct vhost *vhost)
 69 881a9dd9 2021-01-16 op {
 70 881a9dd9 2021-01-16 op 	ssize_t n;
 71 881a9dd9 2021-01-16 op 
 72 881a9dd9 2021-01-16 op 	if (vhost < hosts || vhost > hosts + HOSTSLEN)
 73 881a9dd9 2021-01-16 op 		return 0;
 74 881a9dd9 2021-01-16 op 
 75 881a9dd9 2021-01-16 op 	n = hosts - vhost;
 76 881a9dd9 2021-01-16 op 	return write(fd, &n, sizeof(n)) == sizeof(n);
 77 881a9dd9 2021-01-16 op }
 78 881a9dd9 2021-01-16 op 
 79 881a9dd9 2021-01-16 op int
 80 881a9dd9 2021-01-16 op recv_vhost(int fd, struct vhost **vhost)
 81 881a9dd9 2021-01-16 op {
 82 881a9dd9 2021-01-16 op 	ssize_t n;
 83 881a9dd9 2021-01-16 op 
 84 881a9dd9 2021-01-16 op 	if (read(fd, &n, sizeof(n)) != sizeof(n))
 85 881a9dd9 2021-01-16 op 		return 0;
 86 881a9dd9 2021-01-16 op 
 87 881a9dd9 2021-01-16 op 	if (n < 0 || n > HOSTSLEN)
 88 881a9dd9 2021-01-16 op 		return 0;
 89 881a9dd9 2021-01-16 op 
 90 881a9dd9 2021-01-16 op 	*vhost = &hosts[n];
 91 881a9dd9 2021-01-16 op 	if ((*vhost)->domain == NULL)
 92 881a9dd9 2021-01-16 op 		return 0;
 93 881a9dd9 2021-01-16 op 	return 1;
 94 881a9dd9 2021-01-16 op }
 95 881a9dd9 2021-01-16 op 
 96 881a9dd9 2021-01-16 op /* send d though fd. see /usr/src/usr.sbin/syslogd/privsep_fdpass.c
 97 881a9dd9 2021-01-16 op  * for an example */
 98 881a9dd9 2021-01-16 op int
 99 881a9dd9 2021-01-16 op send_fd(int fd, int d)
100 881a9dd9 2021-01-16 op {
101 881a9dd9 2021-01-16 op 	struct msghdr msg;
102 881a9dd9 2021-01-16 op 	union {
103 881a9dd9 2021-01-16 op 		struct cmsghdr hdr;
104 881a9dd9 2021-01-16 op 		unsigned char buf[CMSG_SPACE(sizeof(int))];
105 881a9dd9 2021-01-16 op 	} cmsgbuf;
106 881a9dd9 2021-01-16 op 	struct cmsghdr *cmsg;
107 881a9dd9 2021-01-16 op 	struct iovec vec;
108 881a9dd9 2021-01-16 op 	int result = 1;
109 881a9dd9 2021-01-16 op 	ssize_t n;
110 881a9dd9 2021-01-16 op 
111 881a9dd9 2021-01-16 op 	memset(&msg, 0, sizeof(msg));
112 881a9dd9 2021-01-16 op 
113 881a9dd9 2021-01-16 op 	if (d >= 0) {
114 881a9dd9 2021-01-16 op 		msg.msg_control = &cmsgbuf.buf;
115 881a9dd9 2021-01-16 op 		msg.msg_controllen = sizeof(cmsgbuf.buf);
116 881a9dd9 2021-01-16 op 		cmsg = CMSG_FIRSTHDR(&msg);
117 881a9dd9 2021-01-16 op 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
118 881a9dd9 2021-01-16 op 		cmsg->cmsg_level = SOL_SOCKET;
119 881a9dd9 2021-01-16 op 		cmsg->cmsg_type = SCM_RIGHTS;
120 881a9dd9 2021-01-16 op 		*(int*)CMSG_DATA(cmsg) = d;
121 881a9dd9 2021-01-16 op 	} else
122 881a9dd9 2021-01-16 op 		result = 0;
123 881a9dd9 2021-01-16 op 
124 881a9dd9 2021-01-16 op 	vec.iov_base = &result;
125 881a9dd9 2021-01-16 op 	vec.iov_len = sizeof(int);
126 881a9dd9 2021-01-16 op 	msg.msg_iov = &vec;
127 881a9dd9 2021-01-16 op 	msg.msg_iovlen = 1;
128 881a9dd9 2021-01-16 op 
129 881a9dd9 2021-01-16 op 	if ((n = sendmsg(fd, &msg, 0)) == -1 || n != sizeof(int)) {
130 881a9dd9 2021-01-16 op                 fprintf(stderr, "sendmsg: got %zu but wanted %zu: (errno) %s",
131 881a9dd9 2021-01-16 op 		    n, sizeof(int), strerror(errno));
132 881a9dd9 2021-01-16 op 		return 0;
133 881a9dd9 2021-01-16 op 	}
134 881a9dd9 2021-01-16 op 	return 1;
135 881a9dd9 2021-01-16 op }
136 881a9dd9 2021-01-16 op 
137 881a9dd9 2021-01-16 op /* receive a descriptor via fd */
138 881a9dd9 2021-01-16 op int
139 881a9dd9 2021-01-16 op recv_fd(int fd)
140 881a9dd9 2021-01-16 op {
141 881a9dd9 2021-01-16 op 	struct msghdr msg;
142 881a9dd9 2021-01-16 op 	union {
143 881a9dd9 2021-01-16 op 		struct cmsghdr hdr;
144 881a9dd9 2021-01-16 op 		char buf[CMSG_SPACE(sizeof(int))];
145 881a9dd9 2021-01-16 op 	} cmsgbuf;
146 881a9dd9 2021-01-16 op 	struct cmsghdr *cmsg;
147 881a9dd9 2021-01-16 op 	struct iovec vec;
148 881a9dd9 2021-01-16 op 	ssize_t n;
149 881a9dd9 2021-01-16 op 	int result;
150 881a9dd9 2021-01-16 op 
151 881a9dd9 2021-01-16 op 	memset(&msg, 0, sizeof(msg));
152 881a9dd9 2021-01-16 op 	vec.iov_base = &result;
153 881a9dd9 2021-01-16 op 	vec.iov_len = sizeof(int);
154 881a9dd9 2021-01-16 op 	msg.msg_iov = &vec;
155 881a9dd9 2021-01-16 op 	msg.msg_iovlen = 1;
156 881a9dd9 2021-01-16 op 	msg.msg_control = &cmsgbuf.buf;
157 881a9dd9 2021-01-16 op 	msg.msg_controllen = sizeof(cmsgbuf.buf);
158 881a9dd9 2021-01-16 op 
159 881a9dd9 2021-01-16 op 	if ((n = recvmsg(fd, &msg, 0)) != sizeof(int)) {
160 881a9dd9 2021-01-16 op 		fprintf(stderr, "read %zu bytes bu wanted %zu\n", n, sizeof(int));
161 881a9dd9 2021-01-16 op 		return -1;
162 881a9dd9 2021-01-16 op 	}
163 881a9dd9 2021-01-16 op 
164 881a9dd9 2021-01-16 op 	if (result) {
165 881a9dd9 2021-01-16 op 		cmsg = CMSG_FIRSTHDR(&msg);
166 881a9dd9 2021-01-16 op 		if (cmsg == NULL || cmsg->cmsg_type != SCM_RIGHTS)
167 881a9dd9 2021-01-16 op 			return -1;
168 881a9dd9 2021-01-16 op 		return (*(int *)CMSG_DATA(cmsg));
169 881a9dd9 2021-01-16 op 	} else
170 881a9dd9 2021-01-16 op 		return -1;
171 881a9dd9 2021-01-16 op }
172 881a9dd9 2021-01-16 op 
173 881a9dd9 2021-01-16 op static inline void
174 881a9dd9 2021-01-16 op safe_setenv(const char *name, const char *val)
175 881a9dd9 2021-01-16 op {
176 881a9dd9 2021-01-16 op 	if (val == NULL)
177 881a9dd9 2021-01-16 op 		val = "";
178 881a9dd9 2021-01-16 op 	setenv(name, val, 1);
179 881a9dd9 2021-01-16 op }
180 881a9dd9 2021-01-16 op 
181 881a9dd9 2021-01-16 op /* fd or -1 on error */
182 881a9dd9 2021-01-16 op static int
183 881a9dd9 2021-01-16 op launch_cgi(const char *spath, const char *relpath, const char *query,
184 881a9dd9 2021-01-16 op     const char *addr, const char *ruser, const char *cissuer, const char *chash,
185 881a9dd9 2021-01-16 op     struct vhost *vhost)
186 881a9dd9 2021-01-16 op {
187 881a9dd9 2021-01-16 op 	int p[2];		/* read end, write end */
188 881a9dd9 2021-01-16 op 
189 881a9dd9 2021-01-16 op 	if (pipe2(p, O_NONBLOCK) == -1)
190 881a9dd9 2021-01-16 op 		return -1;
191 881a9dd9 2021-01-16 op 
192 881a9dd9 2021-01-16 op 	switch (fork()) {
193 881a9dd9 2021-01-16 op 	case -1:
194 881a9dd9 2021-01-16 op 		return -1;
195 881a9dd9 2021-01-16 op 
196 881a9dd9 2021-01-16 op 	case 0: {		/* child */
197 881a9dd9 2021-01-16 op 		char *portno, *ex, *requri;
198 881a9dd9 2021-01-16 op 		char *argv[] = { NULL, NULL, NULL };
199 881a9dd9 2021-01-16 op 
200 881a9dd9 2021-01-16 op 		close(p[0]);
201 881a9dd9 2021-01-16 op 		if (dup2(p[1], 1) == -1)
202 881a9dd9 2021-01-16 op 			goto childerr;
203 881a9dd9 2021-01-16 op 
204 881a9dd9 2021-01-16 op 		if (asprintf(&portno, "%d", conf.port) == -1)
205 881a9dd9 2021-01-16 op 			goto childerr;
206 881a9dd9 2021-01-16 op 
207 881a9dd9 2021-01-16 op 		if (asprintf(&ex, "%s/%s", vhost->dir, spath) == -1)
208 881a9dd9 2021-01-16 op 			goto childerr;
209 881a9dd9 2021-01-16 op 
210 881a9dd9 2021-01-16 op 		if (asprintf(&requri, "%s%s%s", spath,
211 568a09c2 2021-01-18 op 		    (relpath != NULL && *relpath == '\0') ? "" : "/",
212 568a09c2 2021-01-18 op 		    (relpath != NULL ? relpath : "")) == -1)
213 881a9dd9 2021-01-16 op 			goto childerr;
214 881a9dd9 2021-01-16 op 
215 881a9dd9 2021-01-16 op 		argv[0] = argv[1] = ex;
216 881a9dd9 2021-01-16 op 
217 881a9dd9 2021-01-16 op 		safe_setenv("GATEWAY_INTERFACE", "CGI/1.1");
218 28ec6178 2021-01-24 op 		safe_setenv("SERVER_PROTOCOL", "GEMINI");
219 881a9dd9 2021-01-16 op 		safe_setenv("SERVER_SOFTWARE", "gmid");
220 881a9dd9 2021-01-16 op 		safe_setenv("SERVER_PORT", portno);
221 881a9dd9 2021-01-16 op 
222 881a9dd9 2021-01-16 op 		if (!strcmp(vhost->domain, "*"))
223 881a9dd9 2021-01-16 op 			safe_setenv("SERVER_NAME", vhost->domain);
224 881a9dd9 2021-01-16 op 
225 881a9dd9 2021-01-16 op 		safe_setenv("SCRIPT_NAME", spath);
226 881a9dd9 2021-01-16 op 		safe_setenv("SCRIPT_EXECUTABLE", ex);
227 881a9dd9 2021-01-16 op 		safe_setenv("REQUEST_URI", requri);
228 881a9dd9 2021-01-16 op 		safe_setenv("REQUEST_RELATIVE", relpath);
229 881a9dd9 2021-01-16 op 		safe_setenv("QUERY_STRING", query);
230 881a9dd9 2021-01-16 op 		safe_setenv("REMOTE_HOST", addr);
231 881a9dd9 2021-01-16 op 		safe_setenv("REMOTE_ADDR", addr);
232 881a9dd9 2021-01-16 op 		safe_setenv("DOCUMENT_ROOT", vhost->dir);
233 881a9dd9 2021-01-16 op 
234 881a9dd9 2021-01-16 op 		if (ruser != NULL) {
235 881a9dd9 2021-01-16 op 			safe_setenv("AUTH_TYPE", "Certificate");
236 881a9dd9 2021-01-16 op 			safe_setenv("REMOTE_USER", ruser);
237 881a9dd9 2021-01-16 op 			safe_setenv("TLS_CLIENT_ISSUER", cissuer);
238 881a9dd9 2021-01-16 op 			safe_setenv("TLS_CLIENT_HASH", chash);
239 881a9dd9 2021-01-16 op 		}
240 05748e49 2021-01-24 op 
241 0baf6bed 2021-01-24 op 		fchdir(vhost->dirfd);
242 881a9dd9 2021-01-16 op 
243 881a9dd9 2021-01-16 op 		execvp(ex, argv);
244 881a9dd9 2021-01-16 op 		goto childerr;
245 881a9dd9 2021-01-16 op 	}
246 881a9dd9 2021-01-16 op 
247 881a9dd9 2021-01-16 op 	default:
248 881a9dd9 2021-01-16 op 		close(p[1]);
249 881a9dd9 2021-01-16 op 		return p[0];
250 881a9dd9 2021-01-16 op 	}
251 881a9dd9 2021-01-16 op 
252 881a9dd9 2021-01-16 op childerr:
253 881a9dd9 2021-01-16 op 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
254 881a9dd9 2021-01-16 op 	_exit(1);
255 881a9dd9 2021-01-16 op }
256 881a9dd9 2021-01-16 op 
257 881a9dd9 2021-01-16 op int
258 881a9dd9 2021-01-16 op executor_main(int fd)
259 881a9dd9 2021-01-16 op {
260 881a9dd9 2021-01-16 op 	char *spath, *relpath, *query, *addr, *ruser, *cissuer, *chash;
261 881a9dd9 2021-01-16 op         struct vhost *vhost;
262 881a9dd9 2021-01-16 op 	int d;
263 881a9dd9 2021-01-16 op 
264 881a9dd9 2021-01-16 op #ifdef __OpenBSD__
265 881a9dd9 2021-01-16 op 	pledge("stdio sendfd proc exec", NULL);
266 881a9dd9 2021-01-16 op #endif
267 881a9dd9 2021-01-16 op 
268 881a9dd9 2021-01-16 op 	for (;;) {
269 881a9dd9 2021-01-16 op 		if (!recv_string(fd, &spath)
270 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &relpath)
271 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &query)
272 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &addr)
273 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &ruser)
274 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &cissuer)
275 881a9dd9 2021-01-16 op 		    || !recv_string(fd, &chash)
276 881a9dd9 2021-01-16 op 		    || !recv_vhost(fd, &vhost))
277 881a9dd9 2021-01-16 op 			break;
278 881a9dd9 2021-01-16 op 
279 881a9dd9 2021-01-16 op 		d = launch_cgi(spath, relpath, query,
280 881a9dd9 2021-01-16 op 		    addr, ruser, cissuer, chash, vhost);
281 881a9dd9 2021-01-16 op 		if (!send_fd(fd, d))
282 881a9dd9 2021-01-16 op 			break;
283 710a71b2 2021-01-19 op 		close(d);
284 881a9dd9 2021-01-16 op 
285 881a9dd9 2021-01-16 op 		free(spath);
286 881a9dd9 2021-01-16 op 		free(relpath);
287 881a9dd9 2021-01-16 op 		free(query);
288 881a9dd9 2021-01-16 op 		free(addr);
289 881a9dd9 2021-01-16 op 		free(ruser);
290 881a9dd9 2021-01-16 op 		free(cissuer);
291 881a9dd9 2021-01-16 op 		free(chash);
292 881a9dd9 2021-01-16 op 	}
293 881a9dd9 2021-01-16 op 
294 881a9dd9 2021-01-16 op 	/* kill all process in my group.  This means the listener and
295 881a9dd9 2021-01-16 op 	 * every pending CGI script. */
296 881a9dd9 2021-01-16 op 	kill(0, SIGINT);
297 881a9dd9 2021-01-16 op 	return 1;
298 881a9dd9 2021-01-16 op }