1 /*
2  * Copyright (c) 2024 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/socket.h>
19 
20 #include <errno.h>
21 #include <poll.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <stdarg.h>
26 #include <getopt.h>
27 #include <err.h>
28 #include <pwd.h>
29 #include <netdb.h>
30 #include <time.h>
31 #include <unistd.h>
32 
33 #include "got_error.h"
34 
35 #include "got_lib_poll.h"
36 
37 #define SMTP_LINE_MAX	65535
38 
39 static int smtp_timeout = 60; /* in seconds */
40 static char smtp_buf[SMTP_LINE_MAX];
41 static size_t smtp_buflen;
42 
43 __dead static void
44 usage(void)
45 {
46 	fprintf(stderr, "usage: %s [-f sender] [-r responder] "
47 	    "[-s subject] [-h hostname] [-p port] recipient\n", getprogname());
48 	exit(1);
49 }
50 
51 static int
52 dial(const char *host, const char *port)
53 {
54 	struct addrinfo	 hints, *res, *res0;
55 	const char	*cause = NULL;
56 	int		 s, error, save_errno;
57 
58 	memset(&hints, 0, sizeof(hints));
59 	hints.ai_family = AF_UNSPEC;
60 	hints.ai_socktype = SOCK_STREAM;
61 	error = getaddrinfo(host, port, &hints, &res0);
62 	if (error)
63 		errx(1, "failed to resolve %s:%s: %s", host, port,
64 		    gai_strerror(error));
65 
66 	s = -1;
67 	for (res = res0; res; res = res->ai_next) {
68 		s = socket(res->ai_family, res->ai_socktype,
69 		    res->ai_protocol);
70 		if (s == -1) {
71 			cause = "socket";
72 			continue;
73 		}
74 
75 		if (connect(s, res->ai_addr, res->ai_addrlen) == -1) {
76 			cause = "connect";
77 			save_errno = errno;
78 			close(s);
79 			errno = save_errno;
80 			s = -1;
81 			continue;
82 		}
83 
84 		break;
85 	}
86 
87 	freeaddrinfo(res0);
88 	if (s == -1)
89 		err(1, "%s", cause);
90 	return s;
91 }
92 
93 static char *
94 set_default_fromaddr(void)
95 {
96 	struct passwd *pw = NULL;
97 	char *s;
98 	char hostname[255];
99 
100 	pw = getpwuid(getuid());
101 	if (pw == NULL) {
102 		errx(1, "my UID %d was not found in password database",
103 		    getuid());
104 	}
105 	
106 	if (gethostname(hostname, sizeof(hostname)) == -1)
107 		err(1, "gethostname");
108 
109 	if (asprintf(&s, "%s@%s", pw->pw_name, hostname) == -1)
110 		err(1, "asprintf");
111 
112 	return s;
113 }
114 
115 static int
116 read_smtp_code(int s, const char *code)
117 {
118 	const struct got_error *error;
119 	char	*endl;
120 	size_t	 linelen;
121 	ssize_t	 r;
122 
123 	for (;;) {
124 		endl = memmem(smtp_buf, smtp_buflen, "\r\n", 2);
125 		if (endl != NULL)
126 			break;
127 
128 		if (smtp_buflen == sizeof(smtp_buf))
129 			errx(1, "line too long");
130 
131 		error = got_poll_fd(s, POLLIN, smtp_timeout);
132 		if (error)
133 			errx(1, "poll: %s", error->msg);
134 
135 		r = read(s, smtp_buf + smtp_buflen,
136 		    sizeof(smtp_buf) - smtp_buflen);
137 		if (r == -1)
138 			err(1, "read");
139 		if (r == 0)
140 			errx(1, "unexpected EOF");
141 		smtp_buflen += r;
142 	}
143 
144 	linelen = endl - smtp_buf;
145 	if (linelen < 3)
146 		errx(1, "invalid SMTP response");
147 
148 	if (strncmp(code, smtp_buf, 3) != 0) {
149 		smtp_buf[3] = '\0';
150 		warnx("unexpected SMTP message code: %s", smtp_buf);
151 		return -1;
152 	}
153 
154 	/*
155 	 * Normally we would get just one reply, but the regress doesn't
156 	 * use a real SMTP server and queues all the replies upfront.
157 	 */
158 	linelen += 2;
159 	memmove(smtp_buf, smtp_buf + linelen, smtp_buflen - linelen);
160 	smtp_buflen -= linelen;
161 
162 	return 0;
163 }
164 
165 static int
166 send_smtp_msg(int s, const char *fmt, ...)
167 {
168 	const struct got_error *error;
169 	char buf[512];
170 	int len;
171 	va_list ap;
172 
173 	va_start(ap, fmt);
174 	len = vsnprintf(buf, sizeof(buf), fmt, ap);
175 	va_end(ap);
176 	if (len < 0) {
177 		warn("vsnprintf");
178 		return -1;
179 	}
180 	if (len >= sizeof(buf)) {
181 		warnx("%s: buffer too small for message '%s...'",
182 		    __func__, buf);
183 		return -1;
184 	}
185 
186 	error = got_poll_write_full(s, buf, len);
187 	if (error) {
188 		warnx("write: %s", error->msg);
189 		return -1;
190 	}
191 
192 	return 0;
193 }
194 
195 static char *
196 get_datestr(time_t *time, char *datebuf)
197 {
198 	struct tm mytm, *tm;
199 	char *p, *s;
200 
201 	tm = gmtime_r(time, &mytm);
202 	if (tm == NULL)
203 		return NULL;
204 	s = asctime_r(tm, datebuf);
205 	if (s == NULL)
206 		return NULL;
207 	p = strchr(s, '\n');
208 	if (p)
209 		*p = '\0';
210 	return s;
211 }
212 
213 static void
214 send_email(int s, const char *myfromaddr, const char *fromaddr,
215     const char *recipient, const char *replytoaddr,
216     const char *subject)
217 {
218 	const struct got_error *error;
219 	char *line = NULL;
220 	size_t linesize = 0;
221 	ssize_t linelen;
222 	time_t now;
223 	char datebuf[26];
224 	char *datestr;
225 
226 	now = time(NULL);
227 	datestr = get_datestr(&now, datebuf);
228 
229 	if (read_smtp_code(s, "220"))
230 		errx(1, "unexpected SMTP greeting received");
231 
232 	if (send_smtp_msg(s, "HELO localhost\r\n"))
233 		errx(1, "could not send HELO");
234 	if (read_smtp_code(s, "250"))
235 		errx(1, "unexpected SMTP response received");
236 
237 	if (send_smtp_msg(s, "MAIL FROM:<%s>\r\n", myfromaddr))
238 		errx(1, "could not send MAIL FROM");
239 	if (read_smtp_code(s, "250"))
240 		errx(1, "unexpected SMTP response received");
241 
242 	if (send_smtp_msg(s, "RCPT TO:<%s>\r\n", recipient))
243 		errx(1, "could not send MAIL FROM");
244 	if (read_smtp_code(s, "250"))
245 		errx(1, "unexpected SMTP response received");
246 
247 	if (send_smtp_msg(s, "DATA\r\n"))
248 		errx(1, "could not send MAIL FROM");
249 	if (read_smtp_code(s, "354"))
250 		errx(1, "unexpected SMTP response received");
251 
252 	if (send_smtp_msg(s, "From: %s\r\n", fromaddr))
253 		errx(1, "could not send From header");
254 	if (send_smtp_msg(s, "To: %s\r\n", recipient))
255 		errx(1, "could not send To header");
256 	if (replytoaddr) {
257 		if (send_smtp_msg(s, "Reply-To: %s\r\n", replytoaddr))
258 			errx(1, "could not send Reply-To header");
259 	}
260 	if (send_smtp_msg(s, "Date: %s +0000 (UTC)\r\n", datestr))
261 		errx(1, "could not send Date header");
262 
263 	if (send_smtp_msg(s, "Subject: %s\r\n", subject))
264 		errx(1, "could not send Subject header");
265 
266 	if (send_smtp_msg(s, "\r\n"))
267 		errx(1, "could not send body delimiter");
268 
269 	while ((linelen = getline(&line, &linesize, stdin)) != -1) {
270 		if (line[0] == '.') { /* dot stuffing */
271 			error = got_poll_write_full(s, ".", 1);
272 			if (error)
273 				errx(1, "write: %s", error->msg);
274 		}
275 		error = got_poll_write_full(s, line, linelen);
276 		if (error)
277 			errx(1, "write: %s", error->msg);
278 	}
279 
280 	if (send_smtp_msg(s, "\r\n.\r\n"))
281 		errx(1, "could not send data terminator");
282 	if (read_smtp_code(s, "250"))
283 		errx(1, "unexpected SMTP response received");
284 
285 	if (send_smtp_msg(s, "QUIT\r\n"))
286 		errx(1, "could not send QUIT");
287 
288 	if (read_smtp_code(s, "221"))
289 		errx(1, "unexpected SMTP response received");
290 
291 	close(s);
292 	free(line);
293 }
294 
295 int
296 main(int argc, char *argv[])
297 {
298 	char *default_fromaddr = NULL;
299 	const char *fromaddr = NULL, *recipient = NULL, *replytoaddr = NULL;
300 	const char *subject = "gotd notification";
301 	const char *hostname = "127.0.0.1";
302 	const char *port = "25";
303 	const char *errstr;
304 	char *timeoutstr;
305 	int ch, s;
306 
307 	while ((ch = getopt(argc, argv, "f:r:s:h:p:")) != -1) {
308 		switch (ch) {
309 		case 'h':
310 			hostname = optarg;
311 			break;
312 		case 'f':
313 			fromaddr = optarg;
314 			break;
315 		case 'p':
316 			port = optarg;
317 			break;
318 		case 'r':
319 			replytoaddr = optarg;
320 			break;
321 		case 's':
322 			subject = optarg;
323 			break;
324 		default:
325 			usage();
326 			/* NOTREACHED */
327 			break;
328 		}
329 	}
330 
331 	argc -= optind;
332 	argv += optind;
333 
334 	if (argc != 1)
335 		usage();
336 
337 	/* used by the regression test suite */
338 	timeoutstr = getenv("GOT_NOTIFY_EMAIL_TIMEOUT");
339 	if (timeoutstr) {
340 		smtp_timeout = strtonum(timeoutstr, 0, 600, &errstr); 
341 		if (errstr != NULL)
342 			errx(1, "timeout in seconds is %s: %s",
343 			    errstr, timeoutstr);
344 	}
345 
346 #ifndef PROFILE
347 	if (pledge("stdio dns inet getpw", NULL) == -1)
348 		err(1, "pledge");
349 #endif
350 	default_fromaddr = set_default_fromaddr();
351 
352 #ifndef PROFILE
353 	if (pledge("stdio dns inet", NULL) == -1)
354 		err(1, "pledge");
355 #endif
356 
357 	recipient = argv[0];
358 	if (fromaddr == NULL)
359 		fromaddr = default_fromaddr;
360 
361 	s = dial(hostname, port);
362 
363 #ifndef PROFILE
364 	if (pledge("stdio", NULL) == -1)
365 		err(1, "pledge");
366 #endif
367 
368 	send_email(s, default_fromaddr, fromaddr, recipient, replytoaddr,
369 	    subject);
370 
371 	free(default_fromaddr);
372 	return 0;
373 }