1 #include "common.h"
2 #include <ctype.h>
3 #include <plumb.h>
4 #include <libsec.h>
5 #include <auth.h>
6 #include <thread.h>
7 #include "dat.h"
8 
9 #pragma varargck type "M" uchar*
10 #pragma varargck argpos pop3cmd 2
11 
12 typedef struct Pop Pop;
13 struct Pop {
14 	char *freep;	// free this to free the strings below
15 
16 	char *host;
17 	char *user;
18 	char *port;
19 
20 	int ppop;
21 	int refreshtime;
22 	int debug;
23 	int pipeline;
24 	int encrypted;
25 	int needtls;
26 	int notls;
27 	int needssl;
28 
29 	// open network connection
30 	Biobuf bin;
31 	Biobuf bout;
32 	int fd;
33 	char *lastline;	// from Brdstr
34 
35 	Thumbprint *thumb;
36 };
37 
38 char*
39 geterrstr(void)
40 {
41 	static char err[64];
42 
43 	err[0] = '\0';
44 	errstr(err, sizeof(err));
45 	return err;
46 }
47 
48 //
49 // get pop3 response line , without worrying
50 // about multiline responses; the clients
51 // will deal with that.
52 //
53 static int
54 isokay(char *s)
55 {
56 	return s!=nil && strncmp(s, "+OK", 3)==0;
57 }
58 
59 static void
60 pop3cmd(Pop *pop, char *fmt, ...)
61 {
62 	char buf[128], *p;
63 	va_list va;
64 
65 	va_start(va, fmt);
66 	vseprint(buf, buf+sizeof(buf), fmt, va);
67 	va_end(va);
68 
69 	p = buf+strlen(buf);
70 	if(p > (buf+sizeof(buf)-3))
71 		sysfatal("pop3 command too long");
72 
73 	if(pop->debug)
74 		fprint(2, "<- %s\n", buf);
75 	strcpy(p, "\r\n");
76 	Bwrite(&pop->bout, buf, strlen(buf));
77 	Bflush(&pop->bout);
78 }
79 
80 static char*
81 pop3resp(Pop *pop)
82 {
83 	char *s;
84 	char *p;
85 
86 	alarm(60*1000);
87 	if((s = Brdstr(&pop->bin, '\n', 0)) == nil){
88 		close(pop->fd);
89 		pop->fd = -1;
90 		alarm(0);
91 		return "unexpected eof";
92 	}
93 	alarm(0);
94 
95 	p = s+strlen(s)-1;
96 	while(p >= s && (*p == '\r' || *p == '\n'))
97 		*p-- = '\0';
98 
99 	if(pop->debug)
100 		fprint(2, "-> %s\n", s);
101 	free(pop->lastline);
102 	pop->lastline = s;
103 	return s;
104 }
105 
106 #if 0 /* jpc */
107 static int
108 pop3log(char *fmt, ...)
109 {
110 	va_list ap;
111 
112 	va_start(ap,fmt);
113 	syslog(0, "/sys/log/pop3", fmt, ap);
114 	va_end(ap);
115 	return 0;
116 }
117 #endif
118 
119 static char*
120 pop3pushtls(Pop *pop)
121 {
122 	int fd;
123 	uchar digest[SHA1dlen];
124 	TLSconn conn;
125 
126 	memset(&conn, 0, sizeof conn);
127 	// conn.trace = pop3log;
128 	fd = tlsClient(pop->fd, &conn);
129 	if(fd < 0)
130 		return "tls error";
131 	if(conn.cert==nil || conn.certlen <= 0){
132 		close(fd);
133 		return "server did not provide TLS certificate";
134 	}
135 	sha1(conn.cert, conn.certlen, digest, nil);
136 	if(!pop->thumb || !okThumbprint(digest, pop->thumb)){
137 		fmtinstall('H', encodefmt);
138 		close(fd);
139 		free(conn.cert);
140 		fprint(2, "upas/fs pop3: server certificate %.*H not recognized\n", SHA1dlen, digest);
141 		return "bad server certificate";
142 	}
143 	free(conn.cert);
144 	close(pop->fd);
145 	pop->fd = fd;
146 	pop->encrypted = 1;
147 	Binit(&pop->bin, pop->fd, OREAD);
148 	Binit(&pop->bout, pop->fd, OWRITE);
149 	return nil;
150 }
151 
152 //
153 // get capability list, possibly start tls
154 //
155 static char*
156 pop3capa(Pop *pop)
157 {
158 	char *s;
159 	int hastls;
160 
161 	pop3cmd(pop, "CAPA");
162 	if(!isokay(pop3resp(pop)))
163 		return nil;
164 
165 	hastls = 0;
166 	for(;;){
167 		s = pop3resp(pop);
168 		if(strcmp(s, ".") == 0 || strcmp(s, "unexpected eof") == 0)
169 			break;
170 		if(strcmp(s, "STLS") == 0)
171 			hastls = 1;
172 		if(strcmp(s, "PIPELINING") == 0)
173 			pop->pipeline = 1;
174 	}
175 
176 	if(hastls && !pop->notls){
177 		pop3cmd(pop, "STLS");
178 		if(!isokay(s = pop3resp(pop)))
179 			return s;
180 		if((s = pop3pushtls(pop)) != nil)
181 			return s;
182 	}
183 	return nil;
184 }
185 
186 //
187 // log in using APOP if possible, password if allowed by user
188 //
189 static char*
190 pop3login(Pop *pop)
191 {
192 	int n;
193 	char *s, *p, *q;
194 	char ubuf[128], user[128];
195 	char buf[500];
196 	UserPasswd *up;
197 
198 	s = pop3resp(pop);
199 	if(!isokay(s))
200 		return "error in initial handshake";
201 
202 	if(pop->user)
203 		snprint(ubuf, sizeof ubuf, " user=%q", pop->user);
204 	else
205 		ubuf[0] = '\0';
206 
207 	// look for apop banner
208 	if(pop->ppop==0 && (p = strchr(s, '<')) && (q = strchr(p+1, '>'))) {
209 		*++q = '\0';
210 		if((n=auth_respond(p, q-p, user, sizeof user, buf, sizeof buf, auth_getkey, "proto=apop role=client server=%q%s",
211 			pop->host, ubuf)) < 0)
212 			return "factotum failed";
213 		if(user[0]=='\0')
214 			return "factotum did not return a user name";
215 
216 		if(s = pop3capa(pop))
217 			return s;
218 
219 		pop3cmd(pop, "APOP %s %.*s", user, n, buf);
220 		if(!isokay(s = pop3resp(pop)))
221 			return s;
222 
223 		return nil;
224 	} else {
225 		if(pop->ppop == 0)
226 			return "no APOP hdr from server";
227 
228 		if(s = pop3capa(pop))
229 			return s;
230 
231 		if(pop->needtls && !pop->encrypted)
232 			return "could not negotiate TLS";
233 
234 		up = auth_getuserpasswd(auth_getkey, "role=client proto=pass service=pop dom=%q%s",
235 			pop->host, ubuf);
236 		/* up = auth_getuserpasswd(auth_getkey, "proto=pass service=pop dom=%q%s",
237 			pop->host, ubuf); jpc */
238 		if(up == nil)
239 			return "no usable keys found";
240 
241 		pop3cmd(pop, "USER %s", up->user);
242 		if(!isokay(s = pop3resp(pop))){
243 			free(up);
244 			return s;
245 		}
246 		pop3cmd(pop, "PASS %s", up->passwd);
247 		free(up);
248 		if(!isokay(s = pop3resp(pop)))
249 			return s;
250 
251 		return nil;
252 	}
253 }
254 
255 //
256 // dial and handshake with pop server
257 //
258 static char*
259 pop3dial(Pop *pop)
260 {
261 	char *err;
262 
263 	if((pop->fd = dial(netmkaddr(pop->host, "net", pop->needssl ? "pop3s" : "pop3"), 0, 0, 0)) < 0)
264 		return geterrstr();
265 
266 	if(pop->needssl){
267 		if((err = pop3pushtls(pop)) != nil)
268 			return err;
269 	}else{
270 		Binit(&pop->bin, pop->fd, OREAD);
271 		Binit(&pop->bout, pop->fd, OWRITE);
272 	}
273 
274 	if(err = pop3login(pop)) {
275 		close(pop->fd);
276 		return err;
277 	}
278 
279 	return nil;
280 }
281 
282 //
283 // close connection
284 //
285 static void
286 pop3hangup(Pop *pop)
287 {
288 	pop3cmd(pop, "QUIT");
289 	pop3resp(pop);
290 	close(pop->fd);
291 }
292 
293 //
294 // download a single message
295 //
296 static char*
297 pop3download(Pop *pop, Message *m)
298 {
299 	char *s, *f[3], *wp, *ep;
300 	char sdigest[SHA1dlen*2+1];
301 	int i, l, sz;
302 
303 	if(!pop->pipeline)
304 		pop3cmd(pop, "LIST %d", m->mesgno);
305 	if(!isokay(s = pop3resp(pop)))
306 		return s;
307 
308 	if(tokenize(s, f, 3) != 3)
309 		return "syntax error in LIST response";
310 
311 	if(atoi(f[1]) != m->mesgno)
312 		return "out of sync with pop3 server";
313 
314 	sz = atoi(f[2])+200;	/* 200 because the plan9 pop3 server lies */
315 	if(sz == 0)
316 		return "invalid size in LIST response";
317 
318 	m->start = wp = emalloc(sz+1);
319 	ep = wp+sz;
320 
321 	if(!pop->pipeline)
322 		pop3cmd(pop, "RETR %d", m->mesgno);
323 	if(!isokay(s = pop3resp(pop))) {
324 		m->start = nil;
325 		free(wp);
326 		return s;
327 	}
328 
329 	s = nil;
330 	while(wp <= ep) {
331 		s = pop3resp(pop);
332 		if(strcmp(s, "unexpected eof") == 0) {
333 			free(m->start);
334 			m->start = nil;
335 			return "unexpected end of conversation";
336 		}
337 		if(strcmp(s, ".") == 0)
338 			break;
339 
340 		l = strlen(s)+1;
341 		if(s[0] == '.') {
342 			s++;
343 			l--;
344 		}
345 		/*
346 		 * grow by 10%/200bytes - some servers
347 		 *  lie about message sizes
348 		 */
349 		if(wp+l > ep) {
350 			int pos = wp - m->start;
351 			sz += ((sz / 10) < 200)? 200: sz/10;
352 			m->start = erealloc(m->start, sz+1);
353 			wp = m->start+pos;
354 			ep = m->start+sz;
355 		}
356 		memmove(wp, s, l-1);
357 		wp[l-1] = '\n';
358 		wp += l;
359 	}
360 
361 	if(s == nil || strcmp(s, ".") != 0)
362 		return "out of sync with pop3 server";
363 
364 	m->end = wp;
365 
366 	// make sure there's a trailing null
367 	// (helps in body searches)
368 	*m->end = 0;
369 	m->bend = m->rbend = m->end;
370 	m->header = m->start;
371 
372 	// digest message
373 	sha1((uchar*)m->start, m->end - m->start, m->digest, nil);
374 	for(i = 0; i < SHA1dlen; i++)
375 		sprint(sdigest+2*i, "%2.2ux", m->digest[i]);
376 	m->sdigest = s_copy(sdigest);
377 
378 	return nil;
379 }
380 
381 //
382 // check for new messages on pop server
383 // UIDL is not required by RFC 1939, but 
384 // netscape requires it, so almost every server supports it.
385 // we'll use it to make our lives easier.
386 //
387 static char*
388 pop3read(Pop *pop, Mailbox *mb, int doplumb)
389 {
390 	char *s, *p, *uidl, *f[2];
391 	int mesgno, ignore, nnew;
392 	Message *m, *next, **l;
393 
394 	// Some POP servers disallow UIDL if the maildrop is empty.
395 	pop3cmd(pop, "STAT");
396 	if(!isokay(s = pop3resp(pop)))
397 		return s;
398 
399 	// fetch message listing; note messages to grab
400 	l = &mb->root->part;
401 	if(strncmp(s, "+OK 0 ", 6) != 0) {
402 		pop3cmd(pop, "UIDL");
403 		if(!isokay(s = pop3resp(pop)))
404 			return s;
405 
406 		for(;;){
407 			p = pop3resp(pop);
408 			if(strcmp(p, ".") == 0 || strcmp(p, "unexpected eof") == 0)
409 				break;
410 
411 			if(tokenize(p, f, 2) != 2)
412 				continue;
413 
414 			mesgno = atoi(f[0]);
415 			uidl = f[1];
416 			if(strlen(uidl) > 75)	// RFC 1939 says 70 characters max
417 				continue;
418 
419 			ignore = 0;
420 			while(*l != nil) {
421 				if(strcmp((*l)->uidl, uidl) == 0) {
422 					// matches mail we already have, note mesgno for deletion
423 					(*l)->mesgno = mesgno;
424 					ignore = 1;
425 					l = &(*l)->next;
426 					break;
427 				} else {
428 					// old mail no longer in box mark deleted
429 					if(doplumb)
430 						mailplumb(mb, *l, 1);
431 					(*l)->inmbox = 0;
432 					(*l)->deleted = 1;
433 					l = &(*l)->next;
434 				}
435 			}
436 			if(ignore)
437 				continue;
438 
439 			m = newmessage(mb->root);
440 			m->mallocd = 1;
441 			m->inmbox = 1;
442 			m->mesgno = mesgno;
443 			strcpy(m->uidl, uidl);
444 
445 			// chain in; will fill in message later
446 			*l = m;
447 			l = &m->next;
448 		}
449 	}
450 
451 	// whatever is left has been removed from the mbox, mark as deleted
452 	while(*l != nil) {
453 		if(doplumb)
454 			mailplumb(mb, *l, 1);
455 		(*l)->inmbox = 0;
456 		(*l)->deleted = 1;
457 		l = &(*l)->next;
458 	}
459 
460 	// download new messages
461 	nnew = 0;
462 	if(pop->pipeline){
463 		switch(rfork(RFPROC|RFMEM)){
464 		case -1:
465 			fprint(2, "rfork: %r\n");
466 			pop->pipeline = 0;
467 
468 		default:
469 			break;
470 
471 		case 0:
472 			for(m = mb->root->part; m != nil; m = m->next){
473 				if(m->start != nil)
474 					continue;
475 				Bprint(&pop->bout, "LIST %d\r\nRETR %d\r\n", m->mesgno, m->mesgno);
476 			}
477 			Bflush(&pop->bout);
478 			threadexits(nil);
479 			/* _exits(nil); jpc */
480 		}
481 	}
482 
483 	for(m = mb->root->part; m != nil; m = next) {
484 		next = m->next;
485 
486 		if(m->start != nil)
487 			continue;
488 
489 		if(s = pop3download(pop, m)) {
490 			// message disappeared? unchain
491 			fprint(2, "download %d: %s\n", m->mesgno, s);
492 			delmessage(mb, m);
493 			mb->root->subname--;
494 			continue;
495 		}
496 		nnew++;
497 		parse(m, 0, mb, 1);
498 
499 		if(doplumb)
500 			mailplumb(mb, m, 0);
501 	}
502 	if(pop->pipeline)
503 		waitpid();
504 
505 	if(nnew || mb->vers == 0) {
506 		mb->vers++;
507 		henter(PATH(0, Qtop), mb->name,
508 			(Qid){PATH(mb->id, Qmbox), mb->vers, QTDIR}, nil, mb);
509 	}
510 
511 	return nil;	
512 }
513 
514 //
515 // delete marked messages
516 //
517 static void
518 pop3purge(Pop *pop, Mailbox *mb)
519 {
520 	Message *m, *next;
521 
522 	if(pop->pipeline){
523 		switch(rfork(RFPROC|RFMEM)){
524 		case -1:
525 			fprint(2, "rfork: %r\n");
526 			pop->pipeline = 0;
527 
528 		default:
529 			break;
530 
531 		case 0:
532 			for(m = mb->root->part; m != nil; m = next){
533 				next = m->next;
534 				if(m->deleted && m->refs == 0){
535 					if(m->inmbox)
536 						Bprint(&pop->bout, "DELE %d\r\n", m->mesgno);
537 				}
538 			}
539 			Bflush(&pop->bout);
540 			/* _exits(nil); jpc */
541 			threadexits(nil);
542 		}
543 	}
544 	for(m = mb->root->part; m != nil; m = next) {
545 		next = m->next;
546 		if(m->deleted && m->refs == 0) {
547 			if(m->inmbox) {
548 				if(!pop->pipeline)
549 					pop3cmd(pop, "DELE %d", m->mesgno);
550 				if(isokay(pop3resp(pop)))
551 					delmessage(mb, m);
552 			} else
553 				delmessage(mb, m);
554 		}
555 	}
556 }
557 
558 
559 // connect to pop3 server, sync mailbox
560 static char*
561 pop3sync(Mailbox *mb, int doplumb)
562 {
563 	char *err;
564 	Pop *pop;
565 
566 	pop = mb->aux;
567 
568 	if(err = pop3dial(pop)) {
569 		mb->waketime = time(0) + pop->refreshtime;
570 		return err;
571 	}
572 
573 	if((err = pop3read(pop, mb, doplumb)) == nil){
574 		pop3purge(pop, mb);
575 		mb->d->atime = mb->d->mtime = time(0);
576 	}
577 	pop3hangup(pop);
578 	mb->waketime = time(0) + pop->refreshtime;
579 	return err;
580 }
581 
582 static char Epop3ctl[] = "bad pop3 control message";
583 
584 static char*
585 pop3ctl(Mailbox *mb, int argc, char **argv)
586 {
587 	int n;
588 	Pop *pop;
589 	char *m, *me;
590 
591 	pop = mb->aux;
592 	if(argc < 1)
593 		return Epop3ctl;
594 
595 	if(argc==1 && strcmp(argv[0], "debug")==0){
596 		pop->debug = 1;
597 		return nil;
598 	}
599 
600 	if(argc==1 && strcmp(argv[0], "nodebug")==0){
601 		pop->debug = 0;
602 		return nil;
603 	}
604 
605 	if(argc==1 && strcmp(argv[0], "thumbprint")==0){
606 		if(pop->thumb)
607 			freeThumbprints(pop->thumb);
608 		/* pop->thumb = initThumbprints("/sys/lib/tls/mail", "/sys/lib/tls/mail.exclude"); jpc */
609 		m = unsharp("#9/sys/lib/tls/mail");
610 		me = unsharp("#9/sys/lib/tls/mail.exclude");
611 		pop->thumb = initThumbprints(m, me);
612 	}
613 	if(strcmp(argv[0], "refresh")==0){
614 		if(argc==1){
615 			pop->refreshtime = 60;
616 			return nil;
617 		}
618 		if(argc==2){
619 			n = atoi(argv[1]);
620 			if(n < 15)
621 				return Epop3ctl;
622 			pop->refreshtime = n;
623 			return nil;
624 		}
625 	}
626 
627 	return Epop3ctl;
628 }
629 
630 // free extra memory associated with mb
631 static void
632 pop3close(Mailbox *mb)
633 {
634 	Pop *pop;
635 
636 	pop = mb->aux;
637 	free(pop->freep);
638 	free(pop);
639 }
640 
641 //
642 // open mailboxes of the form /pop/host/user or /apop/host/user
643 //
644 char*
645 pop3mbox(Mailbox *mb, char *path)
646 {
647 	char *f[10];
648 	int nf, apop, ppop, popssl, apopssl, apoptls, popnotls, apopnotls, poptls;
649 	Pop *pop;
650 	char *m, *me;
651 
652 	quotefmtinstall();
653 	popssl = strncmp(path, "/pops/", 6) == 0;
654 	apopssl = strncmp(path, "/apops/", 7) == 0;
655 	poptls = strncmp(path, "/poptls/", 8) == 0;
656 	popnotls = strncmp(path, "/popnotls/", 10) == 0;
657 	ppop = popssl || poptls || popnotls || strncmp(path, "/pop/", 5) == 0;
658 	apoptls = strncmp(path, "/apoptls/", 9) == 0;
659 	apopnotls = strncmp(path, "/apopnotls/", 11) == 0;
660 	apop = apopssl || apoptls || apopnotls || strncmp(path, "/apop/", 6) == 0;
661 
662 	if(!ppop && !apop)
663 		return Enotme;
664 
665 	path = strdup(path);
666 	if(path == nil)
667 		return "out of memory";
668 
669 	nf = getfields(path, f, nelem(f), 0, "/");
670 	if(nf != 3 && nf != 4) {
671 		free(path);
672 		return "bad pop3 path syntax /[a]pop[tls|ssl]/system[/user]";
673 	}
674 
675 	pop = emalloc(sizeof(*pop));
676 	pop->freep = path;
677 	pop->host = f[2];
678 	if(nf < 4)
679 		pop->user = nil;
680 	else
681 		pop->user = f[3];
682 	pop->ppop = ppop;
683 	pop->needssl = popssl || apopssl;
684 	pop->needtls = poptls || apoptls;
685 	pop->refreshtime = 60;
686 	pop->notls = popnotls || apopnotls;
687 	/* pop->thumb = initThumbprints("/sys/lib/tls/mail", "/sys/lib/tls/mail.exclude"); jpc */
688 		m = unsharp("#9/sys/lib/tls/mail");
689 		me = unsharp("#9/sys/lib/tls/mail.exclude");
690 		pop->thumb = initThumbprints(m, me);
691 
692 	mb->aux = pop;
693 	mb->sync = pop3sync;
694 	mb->close = pop3close;
695 	mb->ctl = pop3ctl;
696 	mb->d = emalloc(sizeof(*mb->d));
697 
698 	return nil;
699 }
700