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 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)
54 if (*bufp == '+' || *bufp == '-')
59 while (isalpha(*bufp))
65 if (strcmp(buf,"+OK") == 0)
69 #endif /* OPIE_ENABLE */
72 else if (strncmp(buf,"-ERR", 4) == 0)
74 if (stage > STAGE_GETAUTH)
77 * We're checking for "lock busy", "unable to lock",
78 * "already locked", "wait a few minutes" etc. here.
79 * This indicates that we have to wait for the server to
80 * unwedge itself before we can poll again.
82 * PS_LOCKBUSY check empirically verified with two recent
83 * versions of the Berkeley popper; QPOP (version 2.2) and
84 * QUALCOMM Pop server derived from UCB (version 2.1.4-R3)
85 * These are caught by the case-indifferent "lock" check.
86 * The "wait" catches "mail storage services unavailable,
87 * wait a few minutes and try again" on the InterMail server.
89 * If these aren't picked up on correctly, fetchmail will
90 * think there is an authentication failure and wedge the
91 * connection in order to prevent futile polls.
95 else if (strstr(bufp,"lock")
96 || strstr(bufp,"Lock")
97 || strstr(bufp,"LOCK")
98 || strstr(bufp,"wait")
99 /* these are blessed by RFC 2449 */
100 || strstr(bufp,"[IN-USE]")||strstr(bufp,"[LOGIN-DELAY]"))
105 report(stderr, "%s\n", bufp);
117 int pop3_getauth(int sock, struct query *ctl, char *greeting)
118 /* apply for connection authorization */
125 #endif /* OPIE_ENABLE */
129 * This needs to catch both demon.co.uk and demon.net.
130 * If we see either, and we're in multidrop mode, try to use
131 * the SDPS *ENV extension.
133 if (!(ctl->server.sdps) && MULTIDROP(ctl) && strstr(greeting, "demon."))
134 ctl->server.sdps = TRUE;
135 #endif /* SDPS_ENABLE */
138 * In theory, we ought to probe with CAPA here (RFC 2449).
139 * But AFAIK this commpand is not widely implemented, and
140 * we have our own tests for optional commands, and it seems
141 * vanishingly unlikely that the RFC 2449 extended responses
142 * [IN-USE] and [LOGIN-DELAY] will ever be accidentally spoofed.
143 * So we'll not bother, and save ourselves the overhead.
146 switch (ctl->server.protocol) {
149 /* CompuServe POP3 Servers as of 990730 want AUTH first for RPA */
150 if (strstr(ctl->remotename, "@compuserve.com"))
152 /* AUTH command should return a list of available mechanisms */
153 if (gen_transact(sock, "AUTH") == 0)
156 flag has_rpa = FALSE;
158 while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
162 if (strncasecmp(buffer, "rpa", 3) == 0)
165 if (has_rpa && !POP3_auth_rpa(ctl->remotename,
166 ctl->password, sock))
172 #endif /* RPA_ENABLE */
175 /* see RFC1938: A One-Time Password System */
176 if (challenge = strstr(lastok, "otp-")) {
177 char response[OPIE_RESPONSE_MAX+1];
180 i = opiegenerator(challenge, !strcmp(ctl->password, "opie") ? "" : ctl->password, response);
181 if ((i == -2) && !run.poll_interval) {
182 char secret[OPIE_SECRET_MAX+1];
183 fprintf(stderr, _("Secret pass phrase: "));
184 if (opiereadpass(secret, sizeof(secret), 0))
185 i = opiegenerator(challenge, secret, response);
186 memset(secret, 0, sizeof(secret));
194 ok = gen_transact(sock, "PASS %s", response);
197 #endif /* OPIE_ENABLE */
200 * AUTH command may return a list of available mechanisms.
201 * if it doesn't, no harm done.
203 * APOP was introduced in RFC 1450, and POP3 AUTH not until
204 * RFC1734. So the < check is an easy way to prevent AUTH from
205 * being sent to the more primitive POP3 servers dating from
206 * RFC 1081 and RFC 1225, which seem more likely to choke on
207 * it. This certainly catches IMAP-2000's POP3 gateway.
209 * These authentication methods are blessed by RFC1734,
210 * describing the POP3 AUTHentication command.
212 if (strchr(greeting, '<') && gen_transact(sock, "AUTH") == 0)
216 flag has_gssapi = FALSE;
217 #endif /* defined(GSSAPI) */
218 #if defined(KERBEROS_V4) || defined(KERBEROS_V5)
219 flag has_kerberos = FALSE;
220 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
221 flag has_cram = FALSE;
223 flag has_opie = FALSE;
224 #endif /* OPIE_ENABLE */
226 /* determine what authentication methods we have available */
227 while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
232 if (strncasecmp(buffer, "GSSAPI", 8) == 0)
234 #endif /* defined(GSSAPI) */
235 #if defined(KERBEROS_V4) || defined(KERBEROS_V5)
236 if (strncasecmp(buffer, "KERBEROS_V4", 8) == 0)
238 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
239 if (strncasecmp(buffer, "CRAM-MD5", 8) == 0)
242 if (strncasecmp(buffer, "X-OTP", 8) == 0)
244 #endif /* OPIE_ENABLE */
249 return(do_gssauth(sock, "AUTH",
250 ctl->server.truename, ctl->remotename));
251 #endif /* defined(GSSAPI) */
252 #if defined(KERBEROS_V4) || defined(KERBEROS_V5)
254 return(do_rfc1731(sock, "AUTH", ctl->server.truename));
255 #endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
257 return(do_cram_md5(sock, "AUTH", ctl));
260 do_otp(sock, "AUTH", ctl)
261 #endif /* OPIE_ENABLE */
264 /* ordinary validation, no one-time password or RPA */
265 gen_transact(sock, "USER %s", ctl->remotename);
266 ok = gen_transact(sock, "PASS %s", ctl->password);
270 /* build MD5 digest from greeting timestamp + password */
271 /* find start of timestamp */
272 for (start = greeting; *start != 0 && *start != '<'; start++)
276 _("Required APOP timestamp not found in greeting\n"));
280 /* find end of timestamp */
281 for (end = start; *end != 0 && *end != '>'; end++)
283 if (*end == 0 || end == start + 1) {
285 _("Timestamp syntax error in greeting\n"));
291 /* copy timestamp and password into digestion buffer */
292 xalloca(msg, char *, (end-start+1) + strlen(ctl->password) + 1);
294 strcat(msg,ctl->password);
296 strcpy(ctl->digest, MD5Digest((unsigned char *)msg));
298 ok = gen_transact(sock, "APOP %s %s", ctl->remotename, ctl->digest);
302 if ((ok = gen_transact(sock,"USER %s", ctl->remotename)) == 0)
303 ok = gen_transact(sock, "RPOP %s", ctl->password);
307 report(stderr, _("Undefined protocol request in POP3_auth\n"));
313 /* maybe we detected a lock-busy condition? */
314 if (ok == PS_LOCKBUSY)
315 report(stderr, _("lock busy! Is another session active?\n"));
321 * Empirical experience shows some server/OS combinations
322 * may need a brief pause even after any lockfiles on the
323 * server are released, to give the server time to finish
324 * copying back very large mailfolders from the temp-file...
325 * this is only ever an issue with extremely large mailboxes.
327 sleep(3); /* to be _really_ safe, probably need sleep(5)! */
329 /* we're peek-capable if use of TOP is enabled */
330 peek_capable = !(ctl->fetchall || ctl->keep);
337 pop3_gettopid( int sock, int num , char *id)
341 char buf [POPBUFSIZE+1];
342 sprintf( buf, "TOP %d 1", num );
343 if ((ok = gen_transact(sock, buf )) != 0)
346 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
350 if ( ! got_it && ! strncasecmp("Message-Id:", buf, 11 )) {
352 /* prevent stack overflows */
354 sscanf( buf+12, "%s", id);
361 pop3_slowuidl( int sock, struct query *ctl, int *countp, int *newp)
363 /* This approach tries to get the message headers from the
364 * remote hosts and compares the message-id to the already known
366 * + if the first message containes a new id, all messages on
367 * the server will be new
368 * + if the first is known, try to estimate the last known message
369 * on the server and check. If this works you know the total number
370 * of messages to get.
371 * + Otherwise run a binary search to determine the last known message
373 int ok, nolinear = 0;
374 int first_nr, list_len, try_id, try_nr, add_id;
378 if( (ok = pop3_gettopid( sock, 1, id )) != 0 )
381 if( ( first_nr = str_nr_in_list(&ctl->oldsaved, id) ) == -1 ) {
382 /* the first message is unknown -> all messages are new */
387 /* check where we expect the latest known message */
388 list_len = count_list( &ctl->oldsaved );
389 try_id = list_len - first_nr; /* -1 + 1 */
391 if( try_id <= *countp ) {
392 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
395 try_nr = str_nr_last_in_list(&ctl->oldsaved, id);
400 if( try_nr != list_len -1 ) {
401 /* some messages inbetween have been deleted... */
405 for( add_id = 1<<30; add_id > try_id-1; add_id >>= 1 )
407 for( ; add_id; add_id >>= 1 ) {
409 if( try_id - add_id <= 1 ) {
416 if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
418 try_nr = str_nr_in_list(&ctl->oldsaved, id);
425 _("Messages inserted into list on server. Cannot handle this.\n"));
430 /* the first try_id messages are known -> copy them to the newsaved list */
431 for( num = first_nr; num < list_len; num++ )
433 struct idlist *new = save_str(&ctl->newsaved,
434 str_from_nr_list(&ctl->oldsaved, num),
436 new->val.status.num = num - first_nr + 1;
440 free_str_list(&ctl->oldsaved);
445 *newp = *countp - try_id;
449 static int pop3_getrange(int sock,
452 int *countp, int *newp, int *bytes)
453 /* get range of messages to be fetched */
456 char buf [POPBUFSIZE+1];
458 /* Ensure that the new list is properly empty */
459 ctl->newsaved = (struct idlist *)NULL;
462 /* Alain Knaff suggests this, but it's not RFC standard */
464 if ((ok = gen_transact(sock, "MBOX %s", folder)))
468 /* get the total message count */
469 gen_send(sock, "STAT");
470 ok = pop3_ok(sock, buf);
472 sscanf(buf,"%d %d", countp, bytes);
477 * Newer, RFC-1725-conformant POP servers may not have the LAST command.
478 * We work as hard as possible to hide this ugliness, but it makes
479 * counting new messages intrinsically quadratic in the worst case.
483 if (*countp > 0 && !ctl->fetchall)
487 if (!ctl->server.uidl) {
488 gen_send(sock, "LAST");
489 ok = pop3_ok(sock, buf);
494 if (sscanf(buf, "%d", &last) == 0)
496 report(stderr, _("protocol error\n"));
499 *newp = (*countp - last);
503 /* grab the mailbox's UID list */
504 if ((ok = gen_transact(sock, "UIDL")) != 0)
506 /* don't worry, yet! do it the slow way */
507 if((ok = pop3_slowuidl( sock, ctl, countp, newp))!=0)
509 report(stderr, _("protocol error while fetching UIDLs\n"));
518 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
522 else if (sscanf(buf, "%d %s", &num, id) == 2)
526 new = save_str(&ctl->newsaved, id, UID_UNSEEN);
527 new->val.status.num = num;
529 if (str_in_list(&ctl->oldsaved, id, FALSE)) {
530 new->val.status.mark = UID_SEEN;
531 str_set_mark(&ctl->oldsaved, id, UID_SEEN);
544 static int pop3_getsizes(int sock, int count, int *sizes)
545 /* capture the sizes of all messages */
549 if ((ok = gen_transact(sock, "LIST")) != 0)
553 char buf [POPBUFSIZE+1];
555 while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
561 else if (sscanf(buf, "%d %d", &num, &size) == 2)
562 sizes[num - 1] = size;
569 static int pop3_is_old(int sock, struct query *ctl, int num)
570 /* is the given message old? */
573 return (num <= last);
575 return (str_in_list(&ctl->oldsaved,
576 str_find(&ctl->newsaved, num), FALSE));
581 * We could use this to fetch headers only as we do for IMAP. The trouble
582 * is that there's no way to fetch the body only. So the following RETR
583 * would have to re-fetch the header. Enough messages have longer headers
584 * than bodies to make this a net loss.
586 static int pop_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
587 /* request headers of nth message */
590 char buf[POPBUFSIZE+1];
592 gen_send(sock, "TOP %d 0", number);
593 if ((ok = pop3_ok(sock, buf)) != 0)
596 *lenp = -1; /* we got sizes from the LIST response */
602 static int pop3_fetch(int sock, struct query *ctl, int number, int *lenp)
603 /* request nth message */
606 char buf[POPBUFSIZE+1];
610 * See http://www.demon.net/services/mail/sdps-tech.html
611 * for a description of what we're parsing here.
613 if (ctl->server.sdps)
617 sdps_envfrom = (char *)NULL;
618 sdps_envto = (char *)NULL;
619 gen_send(sock, "*ENV %d", number);
621 if (gen_recv(sock, buf, sizeof(buf)))
628 /* No need to wrap envelope from address */
629 sdps_envfrom = xmalloc(strlen(buf)+1);
630 strcpy(sdps_envfrom,buf);
633 /* Wrap address with To: <> so nxtaddr() likes it */
634 sdps_envto = xmalloc(strlen(buf)+7);
635 sprintf(sdps_envto,"To: <%s>",buf);
639 (!(buf[0] == '.' && (buf[1] == '\r' || buf[1] == '\n' || buf[1] == '\0')));
641 #endif /* SDPS_ENABLE */
644 * Though the POP RFCs don't document this fact, on almost every
645 * POP3 server I know of messages are marked "seen" only at the
646 * time the OK response to a RETR is issued.
648 * This means we can use TOP to fetch the message without setting its
649 * seen flag. This is good! It means that if the protocol exchange
650 * craps out during the message, it will still be marked `unseen' on
651 * the server. (Exception: in early 1999 SpryNet's POP3 servers were
652 * reported to mark messages seen on a TOP fetch.)
654 * However...*don't* do this if we're using keep to suppress deletion!
655 * In that case, marking the seen flag is the only way to prevent the
656 * message from being re-fetched on subsequent runs.
658 * Also use RETR if fetchall is on. This gives us a workaround
659 * for servers like usa.net's that bungle TOP. It's pretty
660 * harmless because fetchall guarantees that any message dropped
661 * by an interrupted RETR will be picked up on the next poll of the
664 * We take advantage here of the fact that, according to all the
665 * POP RFCs, "if the number of lines requested by the POP3 client
666 * is greater than than the number of lines in the body, then the
667 * POP3 server sends the entire message.").
669 * The line count passed (99999999) is the maximum value CompuServe will
670 * accept; it's much lower than the natural value 2147483646 (the maximum
671 * twos-complement signed 32-bit integer minus 1) */
672 if (ctl->keep || ctl->fetchall)
673 gen_send(sock, "RETR %d", number);
675 gen_send(sock, "TOP %d 99999999", number);
676 if ((ok = pop3_ok(sock, buf)) != 0)
679 *lenp = -1; /* we got sizes from the LIST response */
684 static int pop3_delete(int sock, struct query *ctl, int number)
685 /* delete a given message */
687 /* actually, mark for deletion -- doesn't happen until QUIT time */
688 return(gen_transact(sock, "DELE %d", number));
691 static int pop3_logout(int sock, struct query *ctl)
692 /* send logout command */
696 ok = gen_transact(sock, "QUIT");
709 const static struct method pop3 =
711 "POP3", /* Post Office Protocol v3 */
713 "pop3", /* standard POP3 port */
714 "pop3s", /* ssl POP3 port */
715 #else /* INET6_ENABLE */
716 110, /* standard POP3 port */
717 995, /* ssl POP3 port */
718 #endif /* INET6_ENABLE */
719 FALSE, /* this is not a tagged protocol */
720 TRUE, /* this uses a message delimiter */
721 pop3_ok, /* parse command response */
722 NULL, /* no password canonicalization */
723 pop3_getauth, /* get authorization */
724 pop3_getrange, /* query range of messages */
725 pop3_getsizes, /* we can get a list of sizes */
726 pop3_is_old, /* how do we tell a message is old? */
727 pop3_fetch, /* request given message */
728 NULL, /* no way to fetch body alone */
729 NULL, /* no message trailer */
730 pop3_delete, /* how to delete a message */
731 pop3_logout, /* log out, we're done */
732 FALSE, /* no, we can't re-poll */
735 int doPOP3 (struct query *ctl)
736 /* retrieve messages using POP3 */
739 if (ctl->mailboxes->id) {
740 fprintf(stderr,_("Option --remote is not supported with POP3\n"));
744 peek_capable = !ctl->fetchall;
745 return(do_protocol(ctl, &pop3));
747 #endif /* POP3_ENABLE */
749 /* pop3.c ends here */