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 <malloc_np.h>
39#include <signal.h>
40#include <strings.h>
41#include <string.h>
42#include <syslog.h>
43#include <unistd.h>
44
45#include "dma.h"
46
47#define MAX_LINE_RFC822	999 /* 998 characters plus \n */
48
49void
50bounce(struct qitem *it, const char *reason)
51{
52	struct queue bounceq;
53	char line[1000];
54	size_t pos;
55	int error;
56
57	/* Don't bounce bounced mails */
58	if (it->sender[0] == 0) {
59		syslog(LOG_INFO, "can not bounce a bounce message, discarding");
60		exit(EX_SOFTWARE);
61	}
62
63	bzero(&bounceq, sizeof(bounceq));
64	LIST_INIT(&bounceq.queue);
65	bounceq.sender = "";
66	if (add_recp(&bounceq, it->sender, EXPAND_WILDCARD) != 0)
67		goto fail;
68
69	if (newspoolf(&bounceq) != 0)
70		goto fail;
71
72	syslog(LOG_ERR, "delivery failed, bouncing as %s", bounceq.id);
73	setlogident("%s", bounceq.id);
74
75	error = fprintf(bounceq.mailf,
76		"Received: from MAILER-DAEMON\n"
77		"\tid %s\n"
78		"\tby %s (%s on %s);\n"
79		"\t%s\n"
80		"X-Original-To: <%s>\n"
81		"From: MAILER-DAEMON <>\n"
82		"To: %s\n"
83		"Subject: Mail delivery failed\n"
84		"Message-Id: <%s@%s>\n"
85		"Date: %s\n"
86		"\n"
87		"This is the %s at %s.\n"
88		"\n"
89		"There was an error delivering your mail to <%s>.\n"
90		"\n"
91		"%s\n"
92		"\n"
93		"%s\n"
94		"\n",
95		bounceq.id,
96		hostname(), VERSION, systemhostname(),
97		rfc822date(),
98		it->addr,
99		it->sender,
100		bounceq.id, hostname(),
101		rfc822date(),
102		VERSION, hostname(),
103		it->addr,
104		reason,
105		config.features & FULLBOUNCE ?
106		    "Original message follows." :
107		    "Message headers follow.");
108	if (error < 0)
109		goto fail;
110
111	if (fseek(it->mailf, 0, SEEK_SET) != 0)
112		goto fail;
113	if (config.features & FULLBOUNCE) {
114		while ((pos = fread(line, 1, sizeof(line), it->mailf)) > 0) {
115			if (fwrite(line, 1, pos, bounceq.mailf) != pos)
116				goto fail;
117		}
118	} else {
119		while (!feof(it->mailf)) {
120			if (fgets(line, sizeof(line), it->mailf) == NULL)
121				break;
122			if (line[0] == '\n')
123				break;
124			if (fwrite(line, strlen(line), 1, bounceq.mailf) != 1)
125				goto fail;
126		}
127	}
128
129	if (linkspool(&bounceq) != 0)
130		goto fail;
131	/* bounce is safe */
132
133	delqueue(it);
134
135	run_queue(&bounceq);
136	/* NOTREACHED */
137
138fail:
139	syslog(LOG_CRIT, "error creating bounce: %m");
140	delqueue(it);
141	exit(EX_IOERR);
142}
143
144struct parse_state {
145	char addr[1000];
146	int pos;
147
148	enum {
149		NONE = 0,
150		START,
151		MAIN,
152		EOL,
153		QUIT
154	} state;
155	int comment;
156	int quote;
157	int brackets;
158	int esc;
159};
160
161/*
162 * Simplified RFC2822 header/address parsing.
163 * We copy escapes and quoted strings directly, since
164 * we have to pass them like this to the mail server anyways.
165 * XXX local addresses will need treatment
166 */
167static int
168parse_addrs(struct parse_state *ps, char *s, struct queue *queue)
169{
170	char *addr;
171
172again:
173	switch (ps->state) {
174	case NONE:
175		return (-1);
176
177	case START:
178		/* init our data */
179		bzero(ps, sizeof(*ps));
180
181		/* skip over header name */
182		while (*s != ':')
183			s++;
184		s++;
185		ps->state = MAIN;
186		break;
187
188	case MAIN:
189		/* all fine */
190		break;
191
192	case EOL:
193		switch (*s) {
194		case ' ':
195		case '\t':
196			ps->state = MAIN;
197			break;
198
199		default:
200			ps->state = QUIT;
201			if (ps->pos != 0)
202				goto newaddr;
203			return (0);
204		}
205		break;
206
207	case QUIT:
208		return (0);
209	}
210
211	for (; *s != 0; s++) {
212		if (ps->esc) {
213			ps->esc = 0;
214
215			switch (*s) {
216			case '\r':
217			case '\n':
218				goto err;
219
220			default:
221				goto copy;
222			}
223		}
224
225		if (ps->quote) {
226			switch (*s) {
227			case '"':
228				ps->quote = 0;
229				goto copy;
230
231			case '\\':
232				ps->esc = 1;
233				goto copy;
234
235			case '\r':
236			case '\n':
237				goto eol;
238
239			default:
240				goto copy;
241			}
242		}
243
244		switch (*s) {
245		case '(':
246			ps->comment++;
247			break;
248
249		case ')':
250			if (ps->comment)
251				ps->comment--;
252			else
253				goto err;
254			goto skip;
255
256		case '"':
257			ps->quote = 1;
258			goto copy;
259
260		case '\\':
261			ps->esc = 1;
262			goto copy;
263
264		case '\r':
265		case '\n':
266			goto eol;
267		}
268
269		if (ps->comment)
270			goto skip;
271
272		switch (*s) {
273		case ' ':
274		case '\t':
275			/* ignore whitespace */
276			goto skip;
277
278		case '<':
279			/* this is the real address now */
280			ps->brackets = 1;
281			ps->pos = 0;
282			goto skip;
283
284		case '>':
285			if (!ps->brackets)
286				goto err;
287			ps->brackets = 0;
288
289			s++;
290			goto newaddr;
291
292		case ':':
293			/* group - ignore */
294			ps->pos = 0;
295			goto skip;
296
297		case ',':
298		case ';':
299			/*
300			 * Next address, copy previous one.
301			 * However, we might be directly after
302			 * a <address>, or have two consecutive
303			 * commas.
304			 * Skip the comma unless there is
305			 * really something to copy.
306			 */
307			if (ps->pos == 0)
308				goto skip;
309			s++;
310			goto newaddr;
311
312		default:
313			goto copy;
314		}
315
316copy:
317		if (ps->comment)
318			goto skip;
319
320		if (ps->pos + 1 == sizeof(ps->addr))
321			goto err;
322		ps->addr[ps->pos++] = *s;
323
324skip:
325		;
326	}
327
328eol:
329	ps->state = EOL;
330	return (0);
331
332err:
333	ps->state = QUIT;
334	return (-1);
335
336newaddr:
337	ps->addr[ps->pos] = 0;
338	ps->pos = 0;
339	addr = strdup(ps->addr);
340	if (addr == NULL)
341		errlog(EX_SOFTWARE, "strdup");
342
343	if (add_recp(queue, addr, EXPAND_WILDCARD) != 0)
344		errlogx(EX_DATAERR, "invalid recipient `%s'", addr);
345
346	goto again;
347}
348
349static int
350writeline(struct queue *queue, const char *line, ssize_t linelen)
351{
352	ssize_t len;
353
354	while (linelen > 0) {
355		len = linelen;
356		if (linelen > MAX_LINE_RFC822) {
357			len = MAX_LINE_RFC822 - 10;
358		}
359
360		if (fwrite(line, len, 1, queue->mailf) != 1)
361			return (-1);
362
363		if (linelen <= MAX_LINE_RFC822)
364			break;
365
366		if (fwrite("\n", 1, 1, queue->mailf) != 1)
367			return (-1);
368
369		line += MAX_LINE_RFC822 - 10;
370		linelen = strlen(line);
371	}
372	return (0);
373}
374
375int
376readmail(struct queue *queue, int nodot, int recp_from_header)
377{
378	struct parse_state parse_state;
379	char *line = NULL;
380	ssize_t linelen;
381	size_t linecap = 0;
382	char newline[MAX_LINE_RFC822 + 1];
383	size_t error;
384	int had_headers = 0;
385	int had_from = 0;
386	int had_messagid = 0;
387	int had_date = 0;
388	int had_first_line = 0;
389	int had_last_line = 0;
390	int nocopy = 0;
391	int ret = -1;
392
393	parse_state.state = NONE;
394
395	error = fprintf(queue->mailf,
396		"Received: from %s (uid %d)\n"
397		"\t(envelope-from %s)\n"
398		"\tid %s\n"
399		"\tby %s (%s on %s);\n"
400		"\t%s\n",
401		username, useruid,
402		queue->sender,
403		queue->id,
404		hostname(), VERSION, systemhostname(),
405		rfc822date());
406	if ((ssize_t)error < 0)
407		return (-1);
408
409	while ((linelen = getline(&line, &linecap, stdin)) > 0) {
410		newline[0] = '\0';
411		if (had_last_line)
412			errlogx(EX_DATAERR, "bad mail input format:"
413				" from %s (uid %d) (envelope-from %s)",
414				username, useruid, queue->sender);
415		linelen = strlen(line);
416		if (linelen == 0 || line[linelen - 1] != '\n') {
417			/*
418			 * This line did not end with a newline character.
419			 * If we fix it, it better be the last line of
420			 * the file.
421			 */
422			if ((size_t)linelen + 1 > linecap) {
423				line = realloc(line, linelen + 2);
424				if (line == NULL)
425					errlogx(EX_SOFTWARE, "realloc");
426				linecap = malloc_usable_size(line);
427			}
428			line[linelen++] = '\n';
429			line[linelen] = 0;
430			had_last_line = 1;
431		}
432		if (!had_first_line) {
433			/*
434			 * Ignore a leading RFC-976 From_ or >From_ line mistakenly
435			 * inserted by some programs.
436			 */
437			if (strprefixcmp(line, "From ") == 0 || strprefixcmp(line, ">From ") == 0)
438				continue;
439			had_first_line = 1;
440		}
441		if (!had_headers) {
442			if (linelen > MAX_LINE_RFC822) {
443				/* XXX also split headers */
444				errlogx(EX_DATAERR, "bad mail input format:"
445				    " from %s (uid %d) (envelope-from %s)",
446				    username, useruid, queue->sender);
447			}
448			/*
449			 * Unless this is a continuation, switch of
450			 * the Bcc: nocopy flag.
451			 */
452			if (!(line[0] == ' ' || line[0] == '\t'))
453				nocopy = 0;
454
455			if (strprefixcmp(line, "Date:") == 0)
456				had_date = 1;
457			else if (strprefixcmp(line, "Message-Id:") == 0)
458				had_messagid = 1;
459			else if (strprefixcmp(line, "From:") == 0)
460				had_from = 1;
461			else if (strprefixcmp(line, "Bcc:") == 0)
462				nocopy = 1;
463
464			if (parse_state.state != NONE) {
465				if (parse_addrs(&parse_state, line, queue) < 0) {
466					errlogx(EX_DATAERR, "invalid address in header\n");
467					/* NOTREACHED */
468				}
469			}
470
471			if (recp_from_header && (
472					strprefixcmp(line, "To:") == 0 ||
473					strprefixcmp(line, "Cc:") == 0 ||
474					strprefixcmp(line, "Bcc:") == 0)) {
475				parse_state.state = START;
476				if (parse_addrs(&parse_state, line, queue) < 0) {
477					errlogx(EX_DATAERR, "invalid address in header\n");
478					/* NOTREACHED */
479				}
480			}
481		}
482
483		if (strcmp(line, "\n") == 0 && !had_headers) {
484			had_headers = 1;
485			while (!had_date || !had_messagid || !had_from) {
486				if (!had_date) {
487					had_date = 1;
488					snprintf(newline, sizeof(newline), "Date: %s\n", rfc822date());
489				} else if (!had_messagid) {
490					/* XXX msgid, assign earlier and log? */
491					had_messagid = 1;
492					snprintf(newline, sizeof(newline), "Message-Id: <%"PRIxMAX".%s.%"PRIxMAX"@%s>\n",
493						 (uintmax_t)time(NULL),
494						 queue->id,
495						 (uintmax_t)random(),
496						 hostname());
497				} else if (!had_from) {
498					had_from = 1;
499					snprintf(newline, sizeof(newline), "From: <%s>\n", queue->sender);
500				}
501				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
502					goto fail;
503			}
504			strlcpy(newline, "\n", sizeof(newline));
505		}
506		if (!nodot && linelen == 2 && line[0] == '.')
507			break;
508		if (!nocopy) {
509			if (newline[0]) {
510				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
511					goto fail;
512			} else {
513				if (writeline(queue, line, linelen) != 0)
514					goto fail;
515			}
516		}
517	}
518	if (ferror(stdin) == 0)
519		ret = 0;
520fail:
521	free(line);
522	return (ret);
523}
524