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_FETCH)
75 else if (stage > STAGE_GETAUTH)
78 * We're checking for "lock busy", "unable to lock",
79 * "already locked", "wait a few minutes" etc. here.
80 * This indicates that we have to wait for the server to
81 * unwedge itself before we can poll again.
83 * PS_LOCKBUSY check empirically verified with two recent
84 * versions of the Berkeley popper; QPOP (version 2.2) and
85 * QUALCOMM Pop server derived from UCB (version 2.1.4-R3)
86 * These are caught by the case-indifferent "lock" check.
87 * The "wait" catches "mail storage services unavailable,
88 * wait a few minutes and try again" on the InterMail server.
90 * If these aren't picked up on correctly, fetchmail will
91 * think there is an authentication failure and wedge the
92 * connection in order to prevent futile polls.
96 else if (strstr(bufp,"lock")
97 || strstr(bufp,"Lock")
98 || strstr(bufp,"LOCK")
99 || strstr(bufp,"wait")
100 /* these are blessed by RFC 2449 */
101 || strstr(bufp,"[IN-USE]")||strstr(bufp,"[LOGIN-DELAY]"))
103 else if ((strstr(bufp,"Service")
104 || strstr(bufp,"service"))
105 && (strstr(bufp,"unavailable")))
110 * We always want to pass the user lock-busy messages, because
111 * they're red flags. Other stuff (like AUTH failures on non-
112 * RFC1734 servers) only if we're debugging.
114 if (*bufp && (ok == PS_LOCKBUSY || outlevel >= O_MONITOR))
115 report(stderr, "%s\n", bufp);
127 static int pop3_getauth(int sock, struct query *ctl, char *greeting)
128 /* apply for connection authorization */
135 #endif /* OPIE_ENABLE */
137 flag has_gssapi = FALSE;
138 #endif /* defined(GSSAPI) */
139 #if defined(KERBEROS_V4) || defined(KERBEROS_V5)
140 flag has_kerberos = FALSE;
141 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
142 flag has_cram = FALSE;
144 flag has_otp = FALSE;
145 #endif /* OPIE_ENABLE */
147 flag has_ssl = FALSE;
148 #endif /* SSL_ENABLE */
152 * This needs to catch both demon.co.uk and demon.net.
153 * If we see either, and we're in multidrop mode, try to use
154 * the SDPS *ENV extension.
156 if (!(ctl->server.sdps) && MULTIDROP(ctl) && strstr(greeting, "demon."))
157 ctl->server.sdps = TRUE;
158 #endif /* SDPS_ENABLE */
160 switch (ctl->server.protocol) {
163 /* CompuServe POP3 Servers as of 990730 want AUTH first for RPA */
164 if (strstr(ctl->remotename, "@compuserve.com"))
166 /* AUTH command should return a list of available mechanisms */
167 if (gen_transact(sock, "AUTH") == 0)
170 flag has_rpa = FALSE;
172 while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
176 if (strncasecmp(buffer, "rpa", 3) == 0)
179 if (has_rpa && !POP3_auth_rpa(ctl->remotename,
180 ctl->password, sock))
186 #endif /* RPA_ENABLE */
189 * CAPA command may return a list including available
190 * authentication mechanisms. if it doesn't, no harm done, we
191 * just fall back to a plain login. Note that this code
192 * latches the server's authentication type, so that in daemon mode
193 * the CAPA check only needs to be done once at start of run.
195 * If CAPA fails, then force the authentication method to PASSORD
196 * and repoll immediately.
198 * These authentication methods are blessed by RFC1734,
199 * describing the POP3 AUTHentication command.
201 if (ctl->server.authenticate == A_ANY)
203 ok = gen_transact(sock, "CAPA");
204 if (ok == PS_SUCCESS)
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"))
233 /* we are in STAGE_GETAUTH! */
234 else if (ok == PS_AUTHFAIL ||
235 /* Some servers directly close the socket. However, if we
236 * have already authenticated before, then a previous CAPA
237 * must have succeeded. In that case, treat this as a
238 * genuine socket error and do not change the auth method.
240 (ok == PS_SOCKET && !ctl->wehaveauthed))
242 ctl->server.authenticate = A_PASSWORD;
243 /* repoll immediately */
250 if (has_ssl && !ctl->use_ssl &&
252 ctl->server.service && (strcmp(ctl->server.service, "pop3s"))
253 #else /* INET6_ENABLE */
254 ctl->server.port != 995
255 #endif /* INET6_ENABLE */
260 realhost = ctl->server.via ? ctl->server.via : ctl->server.pollname; gen_transact(sock, "STLS");
261 if (SSLOpen(sock,ctl->sslcert,ctl->sslkey,ctl->sslproto,ctl->sslcertck, ctl->sslcertpath,ctl->sslfingerprint,realhost,ctl->server.pollname) == -1)
264 GT_("SSL connection failed.\n"));
268 #endif /* SSL_ENABLE */
271 * OK, we have an authentication type now.
273 #if defined(KERBEROS_V4)
275 * Servers doing KPOP have to go through a dummy login sequence
276 * rather than doing SASL.
280 ctl->server.service && (strcmp(ctl->server.service, KPOP_PORT)!=0)
281 #else /* INET6_ENABLE */
282 ctl->server.port != KPOP_PORT
283 #endif /* INET6_ENABLE */
284 && (ctl->server.authenticate == A_KERBEROS_V4
285 || ctl->server.authenticate == A_KERBEROS_V5
286 || ctl->server.authenticate == A_ANY))
288 ok = do_rfc1731(sock, "AUTH", ctl->server.truename);
289 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
292 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
296 (ctl->server.authenticate == A_GSSAPI ||
297 ctl->server.authenticate == A_ANY))
299 ok = do_gssauth(sock,"AUTH",ctl->server.truename,ctl->remotename);
300 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
303 #endif /* defined(GSSAPI) */
307 (ctl->server.authenticate == A_OTP ||
308 ctl->server.authenticate == A_ANY))
310 ok = do_otp(sock, "AUTH", ctl);
311 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
314 #endif /* OPIE_ENABLE */
317 (ctl->server.authenticate == A_CRAM_MD5 ||
318 ctl->server.authenticate == A_ANY))
320 ok = do_cram_md5(sock, "AUTH", ctl, NULL);
321 if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
325 /* ordinary validation, no one-time password or RPA */
326 gen_transact(sock, "USER %s", ctl->remotename);
327 strcpy(shroud, ctl->password);
328 ok = gen_transact(sock, "PASS %s", ctl->password);
333 /* build MD5 digest from greeting timestamp + password */
334 /* find start of timestamp */
335 for (start = greeting; *start != 0 && *start != '<'; start++)
339 GT_("Required APOP timestamp not found in greeting\n"));
343 /* find end of timestamp */
344 for (end = start; *end != 0 && *end != '>'; end++)
346 if (*end == 0 || end == start + 1) {
348 GT_("Timestamp syntax error in greeting\n"));
354 /* copy timestamp and password into digestion buffer */
355 xalloca(msg, char *, (end-start+1) + strlen(ctl->password) + 1);
357 strcat(msg,ctl->password);
359 strcpy(ctl->digest, MD5Digest((unsigned char *)msg));
361 ok = gen_transact(sock, "APOP %s %s", ctl->remotename, ctl->digest);
365 if ((ok = gen_transact(sock,"USER %s", ctl->remotename)) == 0)
366 ok = gen_transact(sock, "RPOP %s", ctl->password);
370 report(stderr, GT_("Undefined protocol request in POP3_auth\n"));
376 /* maybe we detected a lock-busy condition? */
377 if (ok == PS_LOCKBUSY)
378 report(stderr, GT_("lock busy! Is another session active?\n"));
384 * Empirical experience shows some server/OS combinations
385 * may need a brief pause even after any lockfiles on the
386 * server are released, to give the server time to finish
387 * copying back very large mailfolders from the temp-file...
388 * this is only ever an issue with extremely large mailboxes.
390 sleep(3); /* to be _really_ safe, probably need sleep(5)! */
392 /* we're peek-capable if use of TOP is enabled */
393 peek_capable = !(ctl->fetchall || ctl->keep);
399 static int pop3_gettopid( int sock, int num , char *id)
403 char buf [POPBUFSIZE+1];
404 sprintf( buf, "TOP %d 1", num );
405 if ((ok = gen_transact(sock, buf )) != 0)
408 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
412 if ( ! got_it && ! strncasecmp("Message-Id:", buf, 11 )) {
414 /* prevent stack overflows */
416 sscanf( buf+12, "%s", id);
422 static int pop3_slowuidl( int sock, struct query *ctl, int *countp, int *newp)
424 /* This approach tries to get the message headers from the
425 * remote hosts and compares the message-id to the already known
427 * + if the first message containes a new id, all messages on
428 * the server will be new
429 * + if the first is known, try to estimate the last known message
430 * on the server and check. If this works you know the total number
431 * of messages to get.
432 * + Otherwise run a binary search to determine the last known message
434 int ok, nolinear = 0;
435 int first_nr, list_len, try_id, try_nr, add_id;
439 if( (ok = pop3_gettopid( sock, 1, id )) != 0 )
442 if( ( first_nr = str_nr_in_list(&ctl->oldsaved, id) ) == -1 ) {
443 /* the first message is unknown -> all messages are new */
448 /* check where we expect the latest known message */
449 list_len = count_list( &ctl->oldsaved );
450 try_id = list_len - first_nr; /* -1 + 1 */
452 if( try_id <= *countp ) {
453 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
456 try_nr = str_nr_last_in_list(&ctl->oldsaved, id);
461 if( try_nr != list_len -1 ) {
462 /* some messages inbetween have been deleted... */
466 for( add_id = 1<<30; add_id > try_id-1; add_id >>= 1 )
468 for( ; add_id; add_id >>= 1 ) {
470 if( try_id - add_id <= 1 ) {
477 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
479 try_nr = str_nr_in_list(&ctl->oldsaved, id);
486 GT_("Messages inserted into list on server. Cannot handle this.\n"));
491 /* the first try_id messages are known -> copy them to the newsaved list */
492 for( num = first_nr; num < list_len; num++ )
494 struct idlist *new = save_str(&ctl->newsaved,
495 str_from_nr_list(&ctl->oldsaved, num),
497 new->val.status.num = num - first_nr + 1;
501 free_str_list(&ctl->oldsaved);
506 *newp = *countp - try_id;
510 static int pop3_getrange(int sock,
513 int *countp, int *newp, int *bytes)
514 /* get range of messages to be fetched */
517 char buf [POPBUFSIZE+1];
519 /* Ensure that the new list is properly empty */
520 ctl->newsaved = (struct idlist *)NULL;
523 /* Alain Knaff suggests this, but it's not RFC standard */
525 if ((ok = gen_transact(sock, "MBOX %s", folder)))
529 /* get the total message count */
530 gen_send(sock, "STAT");
531 ok = pop3_ok(sock, buf);
533 sscanf(buf,"%d %d", countp, bytes);
538 * Newer, RFC-1725-conformant POP servers may not have the LAST command.
539 * We work as hard as possible to hide this ugliness, but it makes
540 * counting new messages intrinsically quadratic in the worst case.
544 if (*countp > 0 && !ctl->fetchall)
548 if (!ctl->server.uidl) {
549 gen_send(sock, "LAST");
550 ok = pop3_ok(sock, buf);
555 if (sscanf(buf, "%d", &last) == 0)
557 report(stderr, GT_("protocol error\n"));
560 *newp = (*countp - last);
564 /* grab the mailbox's UID list */
565 if ((ok = gen_transact(sock, "UIDL")) != 0)
567 /* don't worry, yet! do it the slow way */
568 if((ok = pop3_slowuidl( sock, ctl, countp, newp))!=0)
570 report(stderr, GT_("protocol error while fetching UIDLs\n"));
579 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
583 else if (sscanf(buf, "%d %s", &num, id) == 2)
587 new = save_str(&ctl->newsaved, id, UID_UNSEEN);
588 new->val.status.num = num;
590 if (str_in_list(&ctl->oldsaved, id, FALSE)) {
591 new->val.status.mark = UID_SEEN;
592 str_set_mark(&ctl->oldsaved, id, UID_SEEN);
605 static int pop3_getsizes(int sock, int count, int *sizes)
606 /* capture the sizes of all messages */
610 if ((ok = gen_transact(sock, "LIST")) != 0)
614 char buf [POPBUFSIZE+1];
616 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
618 unsigned int num, size;
622 else if (sscanf(buf, "%u %u", &num, &size) == 2) {
623 if (num > 0 && num <= count)
624 sizes[num - 1] = size;
626 /* warn about possible attempt to induce buffer overrun */
627 report(stderr, "Warning: ignoring bogus data for message sizes returned by server.\n");
635 static int pop3_is_old(int sock, struct query *ctl, int num)
636 /* is the given message old? */
639 return (num <= last);
641 return (str_in_list(&ctl->oldsaved,
642 str_find(&ctl->newsaved, num), FALSE));
647 * We could use this to fetch headers only as we do for IMAP. The trouble
648 * is that there's no way to fetch the body only. So the following RETR
649 * would have to re-fetch the header. Enough messages have longer headers
650 * than bodies to make this a net loss.
652 static int pop_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
653 /* request headers of nth message */
656 char buf[POPBUFSIZE+1];
658 gen_send(sock, "TOP %d 0", number);
659 if ((ok = pop3_ok(sock, buf)) != 0)
662 *lenp = -1; /* we got sizes from the LIST response */
668 static int pop3_fetch(int sock, struct query *ctl, int number, int *lenp)
669 /* request nth message */
672 char buf[POPBUFSIZE+1];
676 * See http://www.demon.net/services/mail/sdps-tech.html
677 * for a description of what we're parsing here.
679 if (ctl->server.sdps)
683 sdps_envfrom = (char *)NULL;
684 sdps_envto = (char *)NULL;
685 gen_send(sock, "*ENV %d", number);
687 if (gen_recv(sock, buf, sizeof(buf)))
694 /* No need to wrap envelope from address */
695 sdps_envfrom = xmalloc(strlen(buf)+1);
696 strcpy(sdps_envfrom,buf);
699 /* Wrap address with To: <> so nxtaddr() likes it */
700 sdps_envto = xmalloc(strlen(buf)+7);
701 sprintf(sdps_envto,"To: <%s>",buf);
705 (!(buf[0] == '.' && (buf[1] == '\r' || buf[1] == '\n' || buf[1] == '\0')));
707 #endif /* SDPS_ENABLE */
710 * Though the POP RFCs don't document this fact, on almost every
711 * POP3 server I know of messages are marked "seen" only at the
712 * time the OK response to a RETR is issued.
714 * This means we can use TOP to fetch the message without setting its
715 * seen flag. This is good! It means that if the protocol exchange
716 * craps out during the message, it will still be marked `unseen' on
717 * the server. (Exception: in early 1999 SpryNet's POP3 servers were
718 * reported to mark messages seen on a TOP fetch.)
720 * However...*don't* do this if we're using keep to suppress deletion!
721 * In that case, marking the seen flag is the only way to prevent the
722 * message from being re-fetched on subsequent runs.
724 * Also use RETR if fetchall is on. This gives us a workaround
725 * for servers like usa.net's that bungle TOP. It's pretty
726 * harmless because fetchall guarantees that any message dropped
727 * by an interrupted RETR will be picked up on the next poll of the
730 * We take advantage here of the fact that, according to all the
731 * POP RFCs, "if the number of lines requested by the POP3 client
732 * is greater than than the number of lines in the body, then the
733 * POP3 server sends the entire message.").
735 * The line count passed (99999999) is the maximum value CompuServe will
736 * accept; it's much lower than the natural value 2147483646 (the maximum
737 * twos-complement signed 32-bit integer minus 1) */
738 if (ctl->keep || ctl->fetchall)
739 gen_send(sock, "RETR %d", number);
741 gen_send(sock, "TOP %d 99999999", number);
742 if ((ok = pop3_ok(sock, buf)) != 0)
745 *lenp = -1; /* we got sizes from the LIST response */
750 static int pop3_delete(int sock, struct query *ctl, int number)
751 /* delete a given message */
753 /* actually, mark for deletion -- doesn't happen until QUIT time */
754 return(gen_transact(sock, "DELE %d", number));
757 static int pop3_logout(int sock, struct query *ctl)
758 /* send logout command */
764 * We used to do this in case the server marks messages deleted when seen.
765 * (Yes, this has been reported, in the MercuryP/NLM server.
766 * It's even legal under RFC 1939 (section 8) as a site policy.)
767 * It interacted badly with UIDL, though. Thomas Zajic wrote:
768 * "Running 'fetchmail -F -v' and checking the logs, I found out
769 * that fetchmail did in fact flush my mailbox properly, but sent
770 * a RSET just before sending QUIT to log off. This caused the
771 * POP3 server to undo/forget about the previous DELEs, resetting
772 * my mailbox to its original (ie. unflushed) state. The
773 * ~/.fetchids file did get flushed though, so the next time
774 * fetchmail was run it saw all the old messages as new ones ..."
777 gen_transact(sock, "RSET");
778 #endif /* __UNUSED__ */
780 ok = gen_transact(sock, "QUIT");
793 const static struct method pop3 =
795 "POP3", /* Post Office Protocol v3 */
797 "pop3", /* standard POP3 port */
798 "pop3s", /* ssl POP3 port */
799 #else /* INET6_ENABLE */
800 110, /* standard POP3 port */
801 995, /* ssl POP3 port */
802 #endif /* INET6_ENABLE */
803 FALSE, /* this is not a tagged protocol */
804 TRUE, /* this uses a message delimiter */
805 pop3_ok, /* parse command response */
806 pop3_getauth, /* get authorization */
807 pop3_getrange, /* query range of messages */
808 pop3_getsizes, /* we can get a list of sizes */
809 pop3_is_old, /* how do we tell a message is old? */
810 pop3_fetch, /* request given message */
811 NULL, /* no way to fetch body alone */
812 NULL, /* no message trailer */
813 pop3_delete, /* how to delete a message */
814 pop3_logout, /* log out, we're done */
815 FALSE, /* no, we can't re-poll */
818 int doPOP3 (struct query *ctl)
819 /* retrieve messages using POP3 */
822 if (ctl->mailboxes->id) {
823 fprintf(stderr,GT_("Option --remote is not supported with POP3\n"));
827 peek_capable = !ctl->fetchall;
828 return(do_protocol(ctl, &pop3));
830 #endif /* POP3_ENABLE */
832 /* pop3.c ends here */