2 * pop3.c -- POP3 protocol methods
4 * Copyright 1998 by Eric S. Raymond.
5 * For license terms, see the file COPYING in this directory.
13 #if defined(HAVE_UNISTD_H)
16 #if defined(STDC_HEADERS)
20 #include "fetchmail.h"
26 #endif /* OPIE_ENABLE */
28 #ifndef strstr /* glibc-2.1 declares this as a macro */
29 extern char *strstr(); /* needed on sysV68 R3V7.1. */
36 #endif /* SDPS_ENABLE */
39 static char lastok[POPBUFSIZE+1];
40 #endif /* OPIE_ENABLE */
42 #define DOTLINE(s) (s[0] == '.' && (s[1]=='\r'||s[1]=='\n'||s[1]=='\0'))
44 static int pop3_ok (int sock, char *argbuf)
45 /* parse command response */
48 char buf [POPBUFSIZE+1];
51 if ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
53 if (*bufp == '+' || *bufp == '-')
58 while (isalpha(*bufp))
64 if (strcmp(buf,"+OK") == 0)
68 #endif /* OPIE_ENABLE */
71 else if (strncmp(buf,"-ERR", 4) == 0)
73 if (stage > STAGE_GETAUTH)
76 * We're checking for "lock busy", "unable to lock",
77 * "already locked", "wait a few minutes" etc. here.
78 * This indicates that we have to wait for the server to
79 * unwedge itself before we can poll again.
81 * PS_LOCKBUSY check empirically verified with two recent
82 * versions of the Berkeley popper; QPOP (version 2.2) and
83 * QUALCOMM Pop server derived from UCB (version 2.1.4-R3)
84 * These are caught by the case-indifferent "lock" check.
85 * The "wait" catches "mail storage services unavailable,
86 * wait a few minutes and try again" on the InterMail server.
88 * If these aren't picked up on correctly, fetchmail will
89 * think there is an authentication failure and wedge the
90 * connection in order to prevent futile polls.
94 else if (strstr(bufp,"lock")
95 || strstr(bufp,"Lock")
96 || strstr(bufp,"LOCK")
97 || strstr(bufp,"wait")
98 /* these are blessed by RFC 2449 */
99 || strstr(bufp,"[IN-USE]")||strstr(bufp,"[LOGIN-DELAY]"))
101 else if ((strstr(bufp,"Service")
102 || strstr(bufp,"service"))
103 && (strstr(bufp,"unavailable")))
108 * We always want to pass the user lock-busy messages, because
109 * they're red flags. Other stuff (like AUTH failures on non-
110 * RFC1734 servers) only if we're debugging.
112 if (*bufp && (ok == PS_LOCKBUSY || outlevel >= O_MONITOR))
113 report(stderr, "%s\n", bufp);
125 static int pop3_getauth(int sock, struct query *ctl, char *greeting)
126 /* apply for connection authorization */
133 #endif /* OPIE_ENABLE */
135 flag has_gssapi = FALSE;
136 #endif /* defined(GSSAPI) */
137 #if defined(KERBEROS_V4) || defined(KERBEROS_V5)
138 flag has_kerberos = FALSE;
139 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
140 flag has_cram = FALSE;
142 flag has_otp = FALSE;
143 #endif /* OPIE_ENABLE */
145 flag has_ssl = FALSE;
146 #endif /* SSL_ENABLE */
150 * This needs to catch both demon.co.uk and demon.net.
151 * If we see either, and we're in multidrop mode, try to use
152 * the SDPS *ENV extension.
154 if (!(ctl->server.sdps) && MULTIDROP(ctl) && strstr(greeting, "demon."))
155 ctl->server.sdps = TRUE;
156 #endif /* SDPS_ENABLE */
158 switch (ctl->server.protocol) {
161 /* CompuServe POP3 Servers as of 990730 want AUTH first for RPA */
162 if (strstr(ctl->remotename, "@compuserve.com"))
164 /* AUTH command should return a list of available mechanisms */
165 if (gen_transact(sock, "AUTH") == 0)
168 flag has_rpa = FALSE;
170 while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
174 if (strncasecmp(buffer, "rpa", 3) == 0)
177 if (has_rpa && !POP3_auth_rpa(ctl->remotename,
178 ctl->password, sock))
184 #endif /* RPA_ENABLE */
187 * CAPA command may return a list including available
188 * authentication mechanisms. if it doesn't, no harm done, we
189 * just fall back to a plain login. Note that this code
190 * latches the server's authentication type, so that in daemon mode
191 * the CAPA check only needs to be done once at start of run.
193 * APOP was introduced in RFC 1450, and CAPA not until
194 * RFC2449. So the < check is an easy way to prevent CAPA from
195 * being sent to the more primitive POP3 servers dating from
196 * RFC 1081 and RFC 1225, which seem more likely to choke on
197 * it. This certainly catches IMAP-2000's POP3 gateway.
199 * These authentication methods are blessed by RFC1734,
200 * describing the POP3 AUTHentication command.
202 if (ctl->server.authenticate == A_ANY
203 && strchr(greeting, '<')
204 && gen_transact(sock, "CAPA") == 0)
208 /* determine what authentication methods we have available */
209 while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
214 if (strstr(buffer, "STLS"))
216 #endif /* SSL_ENABLE */
218 if (strstr(buffer, "GSSAPI"))
220 #endif /* defined(GSSAPI) */
221 #if defined(KERBEROS_V4)
222 if (strstr(buffer, "KERBEROS_V4"))
224 #endif /* defined(KERBEROS_V4) */
226 if (strstr(buffer, "X-OTP"))
228 #endif /* OPIE_ENABLE */
229 if (strstr(buffer, "CRAM-MD5"))
235 if (has_ssl && !ctl->use_ssl &&
237 ctl->server.service && (strcmp(ctl->server.service, "pop3s"))
238 #else /* INET6_ENABLE */
239 ctl->server.port != 995
240 #endif /* INET6_ENABLE */
245 realhost = ctl->server.via ? ctl->server.via : ctl->server.pollname; gen_transact(sock, "STLS");
246 if (SSLOpen(sock,ctl->sslcert,ctl->sslkey,ctl->sslproto,ctl->sslcertck, ctl->sslcertpath,ctl->sslfingerprint,realhost,ctl->server.pollname) == -1)
249 GT_("SSL connection failed.\n"));
253 #endif /* SSL_ENABLE */
256 * OK, we have an authentication type now.
258 #if defined(KERBEROS_V4)
260 * Servers doing KPOP have to go through a dummy login sequence
261 * rather than doing SASL.
265 ctl->server.service && (strcmp(ctl->server.service, KPOP_PORT)!=0)
266 #else /* INET6_ENABLE */
267 ctl->server.port != KPOP_PORT
268 #endif /* INET6_ENABLE */
269 && (ctl->server.authenticate == A_KERBEROS_V4
270 || ctl->server.authenticate == A_KERBEROS_V5
271 || ctl->server.authenticate == A_ANY))
273 ok = do_rfc1731(sock, "AUTH", ctl->server.truename);
274 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
277 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
281 (ctl->server.authenticate == A_GSSAPI ||
282 ctl->server.authenticate == A_ANY))
284 ok = do_gssauth(sock,"AUTH",ctl->server.truename,ctl->remotename);
285 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
288 #endif /* defined(GSSAPI) */
292 (ctl->server.authenticate == A_OTP ||
293 ctl->server.authenticate == A_ANY))
295 ok = do_otp(sock, "AUTH", ctl);
296 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
299 #endif /* OPIE_ENABLE */
302 (ctl->server.authenticate == A_CRAM_MD5 ||
303 ctl->server.authenticate == A_ANY))
305 ok = do_cram_md5(sock, "AUTH", ctl, NULL);
306 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
310 /* ordinary validation, no one-time password or RPA */
311 gen_transact(sock, "USER %s", ctl->remotename);
312 strcpy(shroud, ctl->password);
313 ok = gen_transact(sock, "PASS %s", ctl->password);
318 /* build MD5 digest from greeting timestamp + password */
319 /* find start of timestamp */
320 for (start = greeting; *start != 0 && *start != '<'; start++)
324 GT_("Required APOP timestamp not found in greeting\n"));
328 /* find end of timestamp */
329 for (end = start; *end != 0 && *end != '>'; end++)
331 if (*end == 0 || end == start + 1) {
333 GT_("Timestamp syntax error in greeting\n"));
339 /* copy timestamp and password into digestion buffer */
340 xalloca(msg, char *, (end-start+1) + strlen(ctl->password) + 1);
342 strcat(msg,ctl->password);
344 strcpy(ctl->digest, MD5Digest((unsigned char *)msg));
346 ok = gen_transact(sock, "APOP %s %s", ctl->remotename, ctl->digest);
350 if ((ok = gen_transact(sock,"USER %s", ctl->remotename)) == 0)
351 ok = gen_transact(sock, "RPOP %s", ctl->password);
355 report(stderr, GT_("Undefined protocol request in POP3_auth\n"));
361 /* maybe we detected a lock-busy condition? */
362 if (ok == PS_LOCKBUSY)
363 report(stderr, GT_("lock busy! Is another session active?\n"));
369 * Empirical experience shows some server/OS combinations
370 * may need a brief pause even after any lockfiles on the
371 * server are released, to give the server time to finish
372 * copying back very large mailfolders from the temp-file...
373 * this is only ever an issue with extremely large mailboxes.
375 sleep(3); /* to be _really_ safe, probably need sleep(5)! */
377 /* we're peek-capable if use of TOP is enabled */
378 peek_capable = !(ctl->fetchall || ctl->keep);
384 static int pop3_gettopid( int sock, int num , char *id)
388 char buf [POPBUFSIZE+1];
389 sprintf( buf, "TOP %d 1", num );
390 if ((ok = gen_transact(sock, buf )) != 0)
393 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
397 if ( ! got_it && ! strncasecmp("Message-Id:", buf, 11 )) {
399 /* prevent stack overflows */
401 sscanf( buf+12, "%s", id);
407 static int pop3_slowuidl( int sock, struct query *ctl, int *countp, int *newp)
409 /* This approach tries to get the message headers from the
410 * remote hosts and compares the message-id to the already known
412 * + if the first message containes a new id, all messages on
413 * the server will be new
414 * + if the first is known, try to estimate the last known message
415 * on the server and check. If this works you know the total number
416 * of messages to get.
417 * + Otherwise run a binary search to determine the last known message
419 int ok, nolinear = 0;
420 int first_nr, list_len, try_id, try_nr, add_id;
424 if( (ok = pop3_gettopid( sock, 1, id )) != 0 )
427 if( ( first_nr = str_nr_in_list(&ctl->oldsaved, id) ) == -1 ) {
428 /* the first message is unknown -> all messages are new */
433 /* check where we expect the latest known message */
434 list_len = count_list( &ctl->oldsaved );
435 try_id = list_len - first_nr; /* -1 + 1 */
437 if( try_id <= *countp ) {
438 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
441 try_nr = str_nr_last_in_list(&ctl->oldsaved, id);
446 if( try_nr != list_len -1 ) {
447 /* some messages inbetween have been deleted... */
451 for( add_id = 1<<30; add_id > try_id-1; add_id >>= 1 )
453 for( ; add_id; add_id >>= 1 ) {
455 if( try_id - add_id <= 1 ) {
462 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
464 try_nr = str_nr_in_list(&ctl->oldsaved, id);
471 GT_("Messages inserted into list on server. Cannot handle this.\n"));
476 /* the first try_id messages are known -> copy them to the newsaved list */
477 for( num = first_nr; num < list_len; num++ )
479 struct idlist *new = save_str(&ctl->newsaved,
480 str_from_nr_list(&ctl->oldsaved, num),
482 new->val.status.num = num - first_nr + 1;
486 free_str_list(&ctl->oldsaved);
491 *newp = *countp - try_id;
495 static int pop3_getrange(int sock,
498 int *countp, int *newp, int *bytes)
499 /* get range of messages to be fetched */
502 char buf [POPBUFSIZE+1];
504 /* Ensure that the new list is properly empty */
505 ctl->newsaved = (struct idlist *)NULL;
508 /* Alain Knaff suggests this, but it's not RFC standard */
510 if ((ok = gen_transact(sock, "MBOX %s", folder)))
514 /* get the total message count */
515 gen_send(sock, "STAT");
516 ok = pop3_ok(sock, buf);
518 sscanf(buf,"%d %d", countp, bytes);
523 * Newer, RFC-1725-conformant POP servers may not have the LAST command.
524 * We work as hard as possible to hide this ugliness, but it makes
525 * counting new messages intrinsically quadratic in the worst case.
529 if (*countp > 0 && !ctl->fetchall)
533 if (!ctl->server.uidl) {
534 gen_send(sock, "LAST");
535 ok = pop3_ok(sock, buf);
540 if (sscanf(buf, "%d", &last) == 0)
542 report(stderr, GT_("protocol error\n"));
545 *newp = (*countp - last);
549 /* grab the mailbox's UID list */
550 if ((ok = gen_transact(sock, "UIDL")) != 0)
552 /* don't worry, yet! do it the slow way */
553 if((ok = pop3_slowuidl( sock, ctl, countp, newp))!=0)
555 report(stderr, GT_("protocol error while fetching UIDLs\n"));
564 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
568 else if (sscanf(buf, "%d %s", &num, id) == 2)
572 new = save_str(&ctl->newsaved, id, UID_UNSEEN);
573 new->val.status.num = num;
575 if (str_in_list(&ctl->oldsaved, id, FALSE)) {
576 new->val.status.mark = UID_SEEN;
577 str_set_mark(&ctl->oldsaved, id, UID_SEEN);
590 static int pop3_getsizes(int sock, int count, int *sizes)
591 /* capture the sizes of all messages */
595 if ((ok = gen_transact(sock, "LIST")) != 0)
599 char buf [POPBUFSIZE+1];
601 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
603 unsigned int num, size;
607 else if (sscanf(buf, "%u %u", &num, &size) == 2) {
608 if (num > 0 && num <= count)
609 sizes[num - 1] = size;
611 /* warn about possible attempt to induce buffer overrun */
612 report(stderr, "Warning: ignoring bogus data for message sizes returned by server.\n");
620 static int pop3_is_old(int sock, struct query *ctl, int num)
621 /* is the given message old? */
624 return (num <= last);
626 return (str_in_list(&ctl->oldsaved,
627 str_find(&ctl->newsaved, num), FALSE));
632 * We could use this to fetch headers only as we do for IMAP. The trouble
633 * is that there's no way to fetch the body only. So the following RETR
634 * would have to re-fetch the header. Enough messages have longer headers
635 * than bodies to make this a net loss.
637 static int pop_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
638 /* request headers of nth message */
641 char buf[POPBUFSIZE+1];
643 gen_send(sock, "TOP %d 0", number);
644 if ((ok = pop3_ok(sock, buf)) != 0)
647 *lenp = -1; /* we got sizes from the LIST response */
653 static int pop3_fetch(int sock, struct query *ctl, int number, int *lenp)
654 /* request nth message */
657 char buf[POPBUFSIZE+1];
661 * See http://www.demon.net/services/mail/sdps-tech.html
662 * for a description of what we're parsing here.
664 if (ctl->server.sdps)
668 sdps_envfrom = (char *)NULL;
669 sdps_envto = (char *)NULL;
670 gen_send(sock, "*ENV %d", number);
672 if (gen_recv(sock, buf, sizeof(buf)))
679 /* No need to wrap envelope from address */
680 sdps_envfrom = xmalloc(strlen(buf)+1);
681 strcpy(sdps_envfrom,buf);
684 /* Wrap address with To: <> so nxtaddr() likes it */
685 sdps_envto = xmalloc(strlen(buf)+7);
686 sprintf(sdps_envto,"To: <%s>",buf);
690 (!(buf[0] == '.' && (buf[1] == '\r' || buf[1] == '\n' || buf[1] == '\0')));
692 #endif /* SDPS_ENABLE */
695 * Though the POP RFCs don't document this fact, on almost every
696 * POP3 server I know of messages are marked "seen" only at the
697 * time the OK response to a RETR is issued.
699 * This means we can use TOP to fetch the message without setting its
700 * seen flag. This is good! It means that if the protocol exchange
701 * craps out during the message, it will still be marked `unseen' on
702 * the server. (Exception: in early 1999 SpryNet's POP3 servers were
703 * reported to mark messages seen on a TOP fetch.)
705 * However...*don't* do this if we're using keep to suppress deletion!
706 * In that case, marking the seen flag is the only way to prevent the
707 * message from being re-fetched on subsequent runs.
709 * Also use RETR if fetchall is on. This gives us a workaround
710 * for servers like usa.net's that bungle TOP. It's pretty
711 * harmless because fetchall guarantees that any message dropped
712 * by an interrupted RETR will be picked up on the next poll of the
715 * We take advantage here of the fact that, according to all the
716 * POP RFCs, "if the number of lines requested by the POP3 client
717 * is greater than than the number of lines in the body, then the
718 * POP3 server sends the entire message.").
720 * The line count passed (99999999) is the maximum value CompuServe will
721 * accept; it's much lower than the natural value 2147483646 (the maximum
722 * twos-complement signed 32-bit integer minus 1) */
723 if (ctl->keep || ctl->fetchall)
724 gen_send(sock, "RETR %d", number);
726 gen_send(sock, "TOP %d 99999999", number);
727 if ((ok = pop3_ok(sock, buf)) != 0)
730 *lenp = -1; /* we got sizes from the LIST response */
735 static int pop3_delete(int sock, struct query *ctl, int number)
736 /* delete a given message */
738 /* actually, mark for deletion -- doesn't happen until QUIT time */
739 return(gen_transact(sock, "DELE %d", number));
742 static int pop3_logout(int sock, struct query *ctl)
743 /* send logout command */
749 * We used to do this in case the server marks messages deleted when seen.
750 * (Yes, this has been reported, in the MercuryP/NLM server.
751 * It's even legal under RFC 1939 (section 8) as a site policy.)
752 * It interacted badly with UIDL, though. Thomas Zajic wrote:
753 * "Running 'fetchmail -F -v' and checking the logs, I found out
754 * that fetchmail did in fact flush my mailbox properly, but sent
755 * a RSET just before sending QUIT to log off. This caused the
756 * POP3 server to undo/forget about the previous DELEs, resetting
757 * my mailbox to its original (ie. unflushed) state. The
758 * ~/.fetchids file did get flushed though, so the next time
759 * fetchmail was run it saw all the old messages as new ones ..."
762 gen_transact(sock, "RSET");
763 #endif /* __UNUSED__ */
765 ok = gen_transact(sock, "QUIT");
778 const static struct method pop3 =
780 "POP3", /* Post Office Protocol v3 */
782 "pop3", /* standard POP3 port */
783 "pop3s", /* ssl POP3 port */
784 #else /* INET6_ENABLE */
785 110, /* standard POP3 port */
786 995, /* ssl POP3 port */
787 #endif /* INET6_ENABLE */
788 FALSE, /* this is not a tagged protocol */
789 TRUE, /* this uses a message delimiter */
790 pop3_ok, /* parse command response */
791 pop3_getauth, /* get authorization */
792 pop3_getrange, /* query range of messages */
793 pop3_getsizes, /* we can get a list of sizes */
794 pop3_is_old, /* how do we tell a message is old? */
795 pop3_fetch, /* request given message */
796 NULL, /* no way to fetch body alone */
797 NULL, /* no message trailer */
798 pop3_delete, /* how to delete a message */
799 pop3_logout, /* log out, we're done */
800 FALSE, /* no, we can't re-poll */
803 int doPOP3 (struct query *ctl)
804 /* retrieve messages using POP3 */
807 if (ctl->mailboxes->id) {
808 fprintf(stderr,GT_("Option --remote is not supported with POP3\n"));
812 peek_capable = !ctl->fetchall;
813 return(do_protocol(ctl, &pop3));
815 #endif /* POP3_ENABLE */
817 /* pop3.c ends here */