1/*
2 * Copyright (c) 2008-2014, Simon Schubert <2@0x2c.org>.
3 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
4 *
5 * This code is derived from software contributed to The DragonFly Project
6 * by Simon Schubert <2@0x2c.org>.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in
16 *    the documentation and/or other materials provided with the
17 *    distribution.
18 * 3. Neither the name of The DragonFly Project nor the names of its
19 *    contributors may be used to endorse or promote products derived
20 *    from this software without specific, prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <errno.h>
37#include <inttypes.h>
38#include <signal.h>
39#include <string.h>
40#include <syslog.h>
41#include <unistd.h>
42
43#include "dma.h"
44
45#define MAX_LINE_RFC822	1000
46
47void
48bounce(struct qitem *it, const char *reason)
49{
50	struct queue bounceq;
51	char line[1000];
52	size_t pos;
53	int error;
54
55	/* Don't bounce bounced mails */
56	if (it->sender[0] == 0) {
57		syslog(LOG_INFO, "can not bounce a bounce message, discarding");
58		exit(EX_SOFTWARE);
59	}
60
61	bzero(&bounceq, sizeof(bounceq));
62	LIST_INIT(&bounceq.queue);
63	bounceq.sender = "";
64	if (add_recp(&bounceq, it->sender, EXPAND_WILDCARD) != 0)
65		goto fail;
66
67	if (newspoolf(&bounceq) != 0)
68		goto fail;
69
70	syslog(LOG_ERR, "delivery failed, bouncing as %s", bounceq.id);
71	setlogident("%s", bounceq.id);
72
73	error = fprintf(bounceq.mailf,
74		"Received: from MAILER-DAEMON\n"
75		"\tid %s\n"
76		"\tby %s (%s);\n"
77		"\t%s\n"
78		"X-Original-To: <%s>\n"
79		"From: MAILER-DAEMON <>\n"
80		"To: %s\n"
81		"Subject: Mail delivery failed\n"
82		"Message-Id: <%s@%s>\n"
83		"Date: %s\n"
84		"\n"
85		"This is the %s at %s.\n"
86		"\n"
87		"There was an error delivering your mail to <%s>.\n"
88		"\n"
89		"%s\n"
90		"\n"
91		"%s\n"
92		"\n",
93		bounceq.id,
94		hostname(), VERSION,
95		rfc822date(),
96		it->addr,
97		it->sender,
98		bounceq.id, hostname(),
99		rfc822date(),
100		VERSION, hostname(),
101		it->addr,
102		reason,
103		config.features & FULLBOUNCE ?
104		    "Original message follows." :
105		    "Message headers follow.");
106	if (error < 0)
107		goto fail;
108
109	if (fseek(it->mailf, 0, SEEK_SET) != 0)
110		goto fail;
111	if (config.features & FULLBOUNCE) {
112		while ((pos = fread(line, 1, sizeof(line), it->mailf)) > 0) {
113			if (fwrite(line, 1, pos, bounceq.mailf) != pos)
114				goto fail;
115		}
116	} else {
117		while (!feof(it->mailf)) {
118			if (fgets(line, sizeof(line), it->mailf) == NULL)
119				break;
120			if (line[0] == '\n')
121				break;
122			if (fwrite(line, strlen(line), 1, bounceq.mailf) != 1)
123				goto fail;
124		}
125	}
126
127	if (linkspool(&bounceq) != 0)
128		goto fail;
129	/* bounce is safe */
130
131	delqueue(it);
132
133	run_queue(&bounceq);
134	/* NOTREACHED */
135
136fail:
137	syslog(LOG_CRIT, "error creating bounce: %m");
138	delqueue(it);
139	exit(EX_IOERR);
140}
141
142struct parse_state {
143	char addr[1000];
144	int pos;
145
146	enum {
147		NONE = 0,
148		START,
149		MAIN,
150		EOL,
151		QUIT
152	} state;
153	int comment;
154	int quote;
155	int brackets;
156	int esc;
157};
158
159/*
160 * Simplified RFC2822 header/address parsing.
161 * We copy escapes and quoted strings directly, since
162 * we have to pass them like this to the mail server anyways.
163 * XXX local addresses will need treatment
164 */
165static int
166parse_addrs(struct parse_state *ps, char *s, struct queue *queue)
167{
168	char *addr;
169
170again:
171	switch (ps->state) {
172	case NONE:
173		return (-1);
174
175	case START:
176		/* init our data */
177		bzero(ps, sizeof(*ps));
178
179		/* skip over header name */
180		while (*s != ':')
181			s++;
182		s++;
183		ps->state = MAIN;
184		break;
185
186	case MAIN:
187		/* all fine */
188		break;
189
190	case EOL:
191		switch (*s) {
192		case ' ':
193		case '\t':
194			s++;
195			/* continue */
196			break;
197
198		default:
199			ps->state = QUIT;
200			if (ps->pos != 0)
201				goto newaddr;
202			return (0);
203		}
204
205	case QUIT:
206		return (0);
207	}
208
209	for (; *s != 0; s++) {
210		if (ps->esc) {
211			ps->esc = 0;
212
213			switch (*s) {
214			case '\r':
215			case '\n':
216				goto err;
217
218			default:
219				goto copy;
220			}
221		}
222
223		if (ps->quote) {
224			switch (*s) {
225			case '"':
226				ps->quote = 0;
227				goto copy;
228
229			case '\\':
230				ps->esc = 1;
231				goto copy;
232
233			case '\r':
234			case '\n':
235				goto eol;
236
237			default:
238				goto copy;
239			}
240		}
241
242		switch (*s) {
243		case '(':
244			ps->comment++;
245			break;
246
247		case ')':
248			if (ps->comment)
249				ps->comment--;
250			else
251				goto err;
252			goto skip;
253
254		case '"':
255			ps->quote = 1;
256			goto copy;
257
258		case '\\':
259			ps->esc = 1;
260			goto copy;
261
262		case '\r':
263		case '\n':
264			goto eol;
265		}
266
267		if (ps->comment)
268			goto skip;
269
270		switch (*s) {
271		case ' ':
272		case '\t':
273			/* ignore whitespace */
274			goto skip;
275
276		case '<':
277			/* this is the real address now */
278			ps->brackets = 1;
279			ps->pos = 0;
280			goto skip;
281
282		case '>':
283			if (!ps->brackets)
284				goto err;
285			ps->brackets = 0;
286
287			s++;
288			goto newaddr;
289
290		case ':':
291			/* group - ignore */
292			ps->pos = 0;
293			goto skip;
294
295		case ',':
296		case ';':
297			/*
298			 * Next address, copy previous one.
299			 * However, we might be directly after
300			 * a <address>, or have two consecutive
301			 * commas.
302			 * Skip the comma unless there is
303			 * really something to copy.
304			 */
305			if (ps->pos == 0)
306				goto skip;
307			s++;
308			goto newaddr;
309
310		default:
311			goto copy;
312		}
313
314copy:
315		if (ps->comment)
316			goto skip;
317
318		if (ps->pos + 1 == sizeof(ps->addr))
319			goto err;
320		ps->addr[ps->pos++] = *s;
321
322skip:
323		;
324	}
325
326eol:
327	ps->state = EOL;
328	return (0);
329
330err:
331	ps->state = QUIT;
332	return (-1);
333
334newaddr:
335	ps->addr[ps->pos] = 0;
336	ps->pos = 0;
337	addr = strdup(ps->addr);
338	if (addr == NULL)
339		errlog(EX_SOFTWARE, "strdup");
340
341	if (add_recp(queue, addr, EXPAND_WILDCARD) != 0)
342		errlogx(EX_DATAERR, "invalid recipient `%s'", addr);
343
344	goto again;
345}
346
347static int
348writeline(struct queue *queue, const char *line, ssize_t linelen)
349{
350	ssize_t len;
351
352	while (linelen > 0) {
353		len = linelen;
354		if (linelen > MAX_LINE_RFC822) {
355			len = MAX_LINE_RFC822 - 10;
356		}
357
358		if (fwrite(line, len, 1, queue->mailf) != 1)
359			return (-1);
360
361		if (linelen <= MAX_LINE_RFC822)
362			break;
363
364		if (fwrite("\n", 1, 1, queue->mailf) != 1)
365			return (-1);
366
367		line += MAX_LINE_RFC822 - 10;
368		linelen = strlen(line);
369	}
370	return (0);
371}
372
373int
374readmail(struct queue *queue, int nodot, int recp_from_header)
375{
376	struct parse_state parse_state;
377	char *line = NULL;
378	ssize_t linelen;
379	size_t linecap = 0;
380	char newline[MAX_LINE_RFC822];
381	size_t error;
382	int had_headers = 0;
383	int had_from = 0;
384	int had_messagid = 0;
385	int had_date = 0;
386	int nocopy = 0;
387	int ret = -1;
388
389	parse_state.state = NONE;
390
391	error = fprintf(queue->mailf,
392		"Received: from %s (uid %d)\n"
393		"\t(envelope-from %s)\n"
394		"\tid %s\n"
395		"\tby %s (%s);\n"
396		"\t%s\n",
397		username, useruid,
398		queue->sender,
399		queue->id,
400		hostname(), VERSION,
401		rfc822date());
402	if ((ssize_t)error < 0)
403		return (-1);
404
405	while (!feof(stdin)) {
406		newline[0] = '\0';
407		if ((linelen = getline(&line, &linecap, stdin)) <= 0)
408			break;
409
410		if (!had_headers) {
411			if (linelen > MAX_LINE_RFC822) {
412				/* XXX also split headers */
413				errlogx(EX_DATAERR, "bad mail input format:"
414				    " from %s (uid %d) (envelope-from %s)",
415				    username, useruid, queue->sender);
416			}
417			/*
418			 * Unless this is a continuation, switch of
419			 * the Bcc: nocopy flag.
420			 */
421			if (!(line[0] == ' ' || line[0] == '\t'))
422				nocopy = 0;
423
424			if (strprefixcmp(line, "Date:") == 0)
425				had_date = 1;
426			else if (strprefixcmp(line, "Message-Id:") == 0)
427				had_messagid = 1;
428			else if (strprefixcmp(line, "From:") == 0)
429				had_from = 1;
430			else if (strprefixcmp(line, "Bcc:") == 0)
431				nocopy = 1;
432
433			if (parse_state.state != NONE) {
434				if (parse_addrs(&parse_state, line, queue) < 0) {
435					errlogx(EX_DATAERR, "invalid address in header\n");
436					/* NOTREACHED */
437				}
438			}
439
440			if (recp_from_header && (
441					strprefixcmp(line, "To:") == 0 ||
442					strprefixcmp(line, "Cc:") == 0 ||
443					strprefixcmp(line, "Bcc:") == 0)) {
444				parse_state.state = START;
445				if (parse_addrs(&parse_state, line, queue) < 0) {
446					errlogx(EX_DATAERR, "invalid address in header\n");
447					/* NOTREACHED */
448				}
449			}
450		}
451
452		if (strcmp(line, "\n") == 0 && !had_headers) {
453			had_headers = 1;
454			while (!had_date || !had_messagid || !had_from) {
455				if (!had_date) {
456					had_date = 1;
457					snprintf(newline, sizeof(newline), "Date: %s\n", rfc822date());
458				} else if (!had_messagid) {
459					/* XXX msgid, assign earlier and log? */
460					had_messagid = 1;
461					snprintf(newline, sizeof(newline), "Message-Id: <%"PRIxMAX".%s.%"PRIxMAX"@%s>\n",
462						 (uintmax_t)time(NULL),
463						 queue->id,
464						 (uintmax_t)random(),
465						 hostname());
466				} else if (!had_from) {
467					had_from = 1;
468					snprintf(newline, sizeof(newline), "From: <%s>\n", queue->sender);
469				}
470				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
471					goto fail;
472			}
473			strlcpy(newline, "\n", sizeof(newline));
474		}
475		if (!nodot && linelen == 2 && line[0] == '.')
476			break;
477		if (!nocopy) {
478			if (newline[0]) {
479				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
480					goto fail;
481			} else {
482				if (writeline(queue, line, linelen) != 0)
483					goto fail;
484			}
485		}
486	}
487
488	ret = 0;
489fail:
490	free(line);
491	return (ret);
492}
493