2 * imap.c -- IMAP2bis/IMAP4 protocol methods
4 * Copyright 1997 by Eric S. Raymond
5 * For license terms, see the file COPYING in this directory.
12 #if defined(STDC_HEADERS)
15 #include "fetchmail.h"
21 #endif /* OPIE_ENABLE */
23 #ifndef strstr /* glibc-2.1 declares this as a macro */
24 extern char *strstr(); /* needed on sysV68 R3V7.1. */
27 /* imap_version values */
28 #define IMAP2 -1 /* IMAP2 or IMAP2BIS, RFC1176 */
29 #define IMAP4 0 /* IMAP4 rev 0, RFC1730 */
30 #define IMAP4rev1 1 /* IMAP4 rev 1, RFC2060 */
32 static int count, unseen, deletions, imap_version, preauth;
33 static int expunged, expunge_period, saved_timeout;
35 static char capabilities[MSGBUFSIZE+1];
36 static unsigned int *unseen_messages;
38 int imap_ok(int sock, char *argbuf)
39 /* parse command response */
41 char buf[MSGBUFSIZE+1];
47 if ((ok = gen_recv(sock, buf, sizeof(buf))))
50 /* all tokens in responses are caseblind */
51 for (cp = buf; *cp; cp++)
55 /* interpret untagged status responses */
56 if (strstr(buf, "* CAPABILITY"))
57 strncpy(capabilities, buf + 12, sizeof(capabilities));
58 else if (strstr(buf, "EXISTS"))
62 * Nasty kluge to handle RFC2177 IDLE. If we know we're idling
63 * we can't wait for the tag matching the IDLE; we have to tell the
64 * server the IDLE is finished by shipping back a DONE when we
65 * see an EXISTS. Only after that will a tagged response be
66 * shipped. The idling flag also gets cleared on a timeout.
68 if (stage == STAGE_IDLE)
70 /* we do our own write and report here to disable tagging */
71 SockWrite(sock, "DONE\r\n", 6);
72 if (outlevel >= O_MONITOR)
73 report(stdout, "IMAP> DONE\n");
75 mytimeout = saved_timeout;
79 else if (strstr(buf, "PREAUTH"))
82 * The server may decide to make the mailbox read-only,
83 * which causes fetchmail to go into a endless loop
84 * fetching the same message over and over again.
86 * However, for check_only, we use EXAMINE which will
87 * mark the mailbox read-only as per the RFC.
89 * This checks for the condition and aborts if
90 * the mailbox is read-only.
92 * See RFC 2060 section 6.3.1 (SELECT).
93 * See RFC 2060 section 6.3.2 (EXAMINE).
95 else if (!check_only && strstr(buf, "[READ-ONLY]"))
98 (tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));
111 for (cp = buf; !isspace(*cp); cp++)
116 if (strncmp(cp, "OK", 2) == 0)
122 else if (strncmp(cp, "BAD", 3) == 0)
124 else if (strncmp(cp, "NO", 2) == 0)
126 if (stage == STAGE_GETAUTH)
127 return(PS_AUTHFAIL); /* RFC2060, 6.2.2 */
139 static tSmbNtlmAuthRequest request;
140 static tSmbNtlmAuthChallenge challenge;
141 static tSmbNtlmAuthResponse response;
144 * NTLM support by Grant Edwards.
146 * Handle MS-Exchange NTLM authentication method. This is the same
147 * as the NTLM auth used by Samba for SMB related services. We just
148 * encode the packets in base64 instead of sending them out via a
151 * Much source (ntlm.h, smb*.c smb*.h) was borrowed from Samba.
154 static int do_imap_ntlm(int sock, struct query *ctl)
159 gen_send(sock, "AUTHENTICATE NTLM");
161 if ((result = gen_recv(sock, msgbuf, sizeof msgbuf)))
164 if (msgbuf[0] != '+')
167 buildSmbNtlmAuthRequest(&request,ctl->remotename,NULL);
169 if (outlevel >= O_DEBUG)
170 dumpSmbNtlmAuthRequest(stdout, &request);
172 memset(msgbuf,0,sizeof msgbuf);
173 to64frombits (msgbuf, (unsigned char*)&request, SmbLength(&request));
175 if (outlevel >= O_MONITOR)
176 report(stdout, "IMAP> %s\n", msgbuf);
178 strcat(msgbuf,"\r\n");
179 SockWrite (sock, msgbuf, strlen (msgbuf));
181 if ((gen_recv(sock, msgbuf, sizeof msgbuf)))
184 len = from64tobits ((unsigned char*)&challenge, msgbuf);
186 if (outlevel >= O_DEBUG)
187 dumpSmbNtlmAuthChallenge(stdout, &challenge);
189 buildSmbNtlmAuthResponse(&challenge, &response,ctl->remotename,ctl->password);
191 if (outlevel >= O_DEBUG)
192 dumpSmbNtlmAuthResponse(stdout, &response);
194 memset(msgbuf,0,sizeof msgbuf);
195 to64frombits (msgbuf, (unsigned char*)&response, SmbLength(&response));
197 if (outlevel >= O_MONITOR)
198 report(stdout, "IMAP> %s\n", msgbuf);
200 strcat(msgbuf,"\r\n");
201 SockWrite (sock, msgbuf, strlen (msgbuf));
203 if ((result = gen_recv (sock, msgbuf, sizeof msgbuf)))
206 if (strstr (msgbuf, "OK"))
213 int imap_canonicalize(char *result, char *raw, int maxlen)
214 /* encode an IMAP password as per RFC1730's quoting conventions */
219 for (i = 0; i < strlen(raw) && i < maxlen; i++)
221 if ((raw[i] == '\\') || (raw[i] == '"'))
223 result[j++] = raw[i];
230 int imap_getauth(int sock, struct query *ctl, char *greeting)
231 /* apply for connection authorization */
235 /* probe to see if we're running IMAP4 and can use RFC822.PEEK */
236 capabilities[0] = '\0';
237 if ((ok = gen_transact(sock, "CAPABILITY")) == PS_SUCCESS)
239 /* UW-IMAP server 10.173 notifies in all caps */
240 if (strstr(capabilities, "IMAP4REV1"))
242 imap_version = IMAP4rev1;
243 if (outlevel >= O_DEBUG)
244 report(stdout, _("Protocol identified as IMAP4 rev 1\n"));
248 imap_version = IMAP4;
249 if (outlevel >= O_DEBUG)
250 report(stdout, _("Protocol identified as IMAP4 rev 0\n"));
253 else if (ok == PS_ERROR)
255 imap_version = IMAP2;
256 if (outlevel >= O_DEBUG)
257 report(stdout, _("Protocol identified as IMAP2 or IMAP2BIS\n"));
262 peek_capable = (imap_version >= IMAP4);
265 * Assumption: expunges are cheap, so we want to do them
266 * after every message unless user said otherwise.
268 if (NUM_SPECIFIED(ctl->expunge))
269 expunge_period = NUM_VALUE_OUT(ctl->expunge);
274 * Handle idling. We depend on coming through here on startup
275 * and after each timeout (including timeouts during idles).
277 if (strstr(capabilities, "IDLE") && ctl->idle)
280 if (outlevel >= O_VERBOSE)
281 report(stdout, _("will idle after poll\n"));
285 * If either (a) we saw a PREAUTH token in the greeting, or
286 * (b) the user specified ssh preauthentication, then we're done.
288 if (preauth || ctl->server.authenticate == A_SSH)
290 preauth = FALSE; /* reset for the next session */
295 * Time to authenticate the user.
296 * Try the protocol variants that don't require passwords first.
299 if ((ctl->server.authenticate == A_ANY
300 || ctl->server.authenticate==A_GSSAPI)
301 && strstr(capabilities, "AUTH=GSSAPI"))
302 return(do_gssauth(sock, "AUTHENTICATE", ctl->server.truename, ctl->remotename));
306 if ((ctl->server.authenticate == A_ANY
307 || ctl->server.authenticate==A_KERBEROS_V4
308 || ctl->server.authenticate==A_KERBEROS_V5)
309 && strstr(capabilities, "AUTH=KERBEROS_V4"))
311 if ((ok = do_rfc1731(sock, "AUTHENTICATE", ctl->server.truename)))
312 /* SASL cancellation of authentication */
316 #endif /* KERBEROS_V4 */
319 * No such luck. OK, now try the variants that mask your password
320 * in a challenge-response.
323 if ((ctl->server.authenticate == A_ANY
324 || ctl->server.authenticate==A_CRAM_MD5)
325 && strstr(capabilities, "AUTH=CRAM-MD5"))
327 if ((ok = do_cram_md5 (sock, "AUTHENTICATE", ctl)))
328 /* SASL cancellation of authentication */
334 if ((ctl->server.authenticate == A_ANY
335 || ctl->server.authenticate==A_OTP)
336 && strstr(capabilities, "AUTH=X-OTP"))
337 return(do_otp(sock, "AUTHENTICATE", ctl));
339 if (ctl->server.authenticate==A_NTLM)
342 _("Required OTP capability not compiled into fetchmail\n"));
345 #endif /* OPIE_ENABLE */
348 if ((ctl->server.authenticate == A_ANY
349 || ctl->server.authenticate==A_NTLM)
350 && strstr (capabilities, "AUTH=NTLM"))
351 return(do_imap_ntlm(sock, ctl));
353 if (ctl->server.authenticate==A_NTLM)
356 _("Required NTLM capability not compiled into fetchmail\n"));
359 #endif /* NTLM_ENABLE */
361 #ifdef __UNUSED__ /* The Cyrus IMAP4rev1 server chokes on this */
362 /* this handles either AUTH=LOGIN or AUTH-LOGIN */
363 if ((imap_version >= IMAP4rev1) && (!strstr(capabilities, "LOGIN")))
366 _("Required LOGIN capability not supported by server\n"));
369 #endif /* __UNUSED__ */
371 /* we're stuck with sending the password en clair */
373 /* these sizes guarantee no buffer overflow */
374 char remotename[NAMELEN*2+1], password[PASSWORDLEN*2+1];
376 imap_canonicalize(remotename, ctl->remotename, NAMELEN);
377 imap_canonicalize(password, ctl->password, PASSWORDLEN);
378 ok = gen_transact(sock, "LOGIN \"%s\" \"%s\"", remotename, password);
387 static int internal_expunge(int sock)
388 /* ship an expunge, resetting associated counters */
392 if ((ok = gen_transact(sock, "EXPUNGE")))
395 expunged += deletions;
398 #ifdef IMAP_UID /* not used */
400 #endif /* IMAP_UID */
405 static int imap_idle(int sock)
406 /* start an RFC2177 IDLE */
409 saved_timeout = mytimeout;
412 return (gen_transact(sock, "IDLE"));
415 static int imap_getrange(int sock,
418 int *countp, int *newp, int *bytes)
419 /* get range of messages to be fetched */
422 char buf[MSGBUFSIZE+1], *cp;
424 /* find out how many messages are waiting */
430 * We have to have an expunge here, otherwise the re-poll will
431 * infinite-loop picking up un-expunged messages -- unless the
432 * expunge period is one and we've been nuking each message
433 * just after deletion.
436 if (deletions && expunge_period != 1)
437 ok = internal_expunge(sock);
440 ok = imap_idle(sock);
441 if (ok || gen_transact(sock, "NOOP"))
443 report(stderr, _("re-poll failed\n"));
446 else if (count == -1) /* no EXISTS response to NOOP/IDLE */
450 if (outlevel >= O_DEBUG)
451 report(stdout, _("%d messages waiting after re-poll\n"), count);
455 ok = gen_transact(sock,
456 check_only ? "EXAMINE \"%s\"" : "SELECT \"%s\"",
457 folder ? folder : "INBOX");
460 report(stderr, _("mailbox selection failed\n"));
463 else if (outlevel >= O_DEBUG)
464 report(stdout, _("%d messages waiting after first poll\n"), count);
466 /* no messages? then we may need to idle until we get some */
467 if (count == 0 && do_idle)
473 /* OK, now get a count of unseen messages and their indices */
474 if (!ctl->fetchall && count > 0)
477 free(unseen_messages);
478 unseen_messages = xmalloc(count * sizeof(unsigned int));
479 memset(unseen_messages, 0, count * sizeof(unsigned int));
482 gen_send(sock, "SEARCH UNSEEN");
484 ok = gen_recv(sock, buf, sizeof(buf));
487 report(stderr, _("search for unseen messages failed\n"));
490 else if ((cp = strstr(buf, "* SEARCH")))
494 cp += 8; /* skip "* SEARCH" */
496 while (*cp && unseen < count)
498 /* skip whitespace */
499 while (*cp && isspace(*cp))
504 * Message numbers are between 1 and 2^32 inclusive,
505 * so unsigned int is large enough.
507 unseen_messages[unseen]=(unsigned int)strtol(cp,&ep,10);
509 if (outlevel >= O_DEBUG)
512 unseen_messages[unseen]);
520 (tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));
529 static int imap_getsizes(int sock, int count, int *sizes)
530 /* capture the sizes of all messages */
532 char buf [MSGBUFSIZE+1];
535 * Some servers (as in, PMDF5.1-9.1 under OpenVMS 6.1)
536 * won't accept 1:1 as valid set syntax. Some implementors
537 * should be taken out and shot for excessive anality.
539 * Microsoft Exchange (brain-dead piece of crap that it is)
540 * sometimes gets its knickers in a knot about bodiless messages.
541 * You may see responses like this:
543 * fetchmail: IMAP> A0004 FETCH 1:9 RFC822.SIZE
544 * fetchmail: IMAP< * 2 FETCH (RFC822.SIZE 1187)
545 * fetchmail: IMAP< * 3 FETCH (RFC822.SIZE 3954)
546 * fetchmail: IMAP< * 4 FETCH (RFC822.SIZE 1944)
547 * fetchmail: IMAP< * 5 FETCH (RFC822.SIZE 2933)
548 * fetchmail: IMAP< * 6 FETCH (RFC822.SIZE 1854)
549 * fetchmail: IMAP< * 7 FETCH (RFC822.SIZE 34054)
550 * fetchmail: IMAP< * 8 FETCH (RFC822.SIZE 5561)
551 * fetchmail: IMAP< * 9 FETCH (RFC822.SIZE 1101)
552 * fetchmail: IMAP< A0004 NO The requested item could not be found.
554 * This means message 1 has only headers. For kicks and grins
555 * you can telnet in and look:
557 * A003 NO The requested item could not be found.
558 * A004 fetch 1 rfc822.header
559 * A004 NO The requested item could not be found.
561 * * 1 FETCH (BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 35 3))
562 * A006 OK FETCH completed.
564 * To get around this, we terminate the read loop on a NO and count
565 * on the fact that the sizes array has been preinitialized with a
566 * known-bad size value.
569 gen_send(sock, "FETCH 1 RFC822.SIZE", count);
571 gen_send(sock, "FETCH 1:%d RFC822.SIZE", count);
576 if ((ok = gen_recv(sock, buf, sizeof(buf))))
578 else if (strstr(buf, "OK") || strstr(buf, "NO"))
580 else if (sscanf(buf, "* %d FETCH (RFC822.SIZE %d)", &num, &size) == 2)
581 sizes[num - 1] = size;
587 static int imap_is_old(int sock, struct query *ctl, int number)
588 /* is the given message old? */
594 * Expunges change the fetch numbers, but unseen_messages contains
595 * indices from before any expungees were done. So neither the
596 * argument nor the values in message_sequence need to be decremented.
600 for (i = 0; i < unseen; i++)
601 if (unseen_messages[i] == number)
610 static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
611 /* request headers of nth message */
613 char buf [MSGBUFSIZE+1];
616 /* expunges change the fetch numbers */
620 * This is blessed by RFC1176, RFC1730, RFC2060.
621 * According to the RFCs, it should *not* set the \Seen flag.
623 gen_send(sock, "FETCH %d RFC822.HEADER", number);
625 /* looking for FETCH response */
629 if ((ok = gen_recv(sock, buf, sizeof(buf))))
632 (sscanf(buf+2, "%d FETCH (%*s {%d}", &num, lenp) != 2);
640 static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
641 /* request body of nth message */
643 char buf [MSGBUFSIZE+1], *cp;
646 /* expunges change the fetch numbers */
650 * If we're using IMAP4, we can fetch the message without setting its
651 * seen flag. This is good! It means that if the protocol exchange
652 * craps out during the message, it will still be marked `unseen' on
655 * However...*don't* do this if we're using keep to suppress deletion!
656 * In that case, marking the seen flag is the only way to prevent the
657 * message from being re-fetched on subsequent runs (and according
658 * to RFC2060 p.43 this fetch should set Seen as a side effect).
660 * According to RFC2060, and Mark Crispin the IMAP maintainer,
661 * FETCH %d BODY[TEXT] and RFC822.TEXT are "functionally
662 * equivalent". However, we know of at least one server that
663 * treats them differently in the presence of MIME attachments;
664 * the latter form downloads the attachment, the former does not.
665 * The server is InterChange, and the fool who implemented this
666 * misfeature ought to be strung up by his thumbs.
668 * When I tried working around this by disabling use of the 4rev1 form,
669 * I found that doing this breaks operation with M$ Exchange.
670 * Annoyingly enough, Exchange's refusal to cope is technically legal
671 * under RFC2062. Trust Microsoft, the Great Enemy of interoperability
672 * standards, to find a way to make standards compliance irritating....
674 switch (imap_version)
676 case IMAP4rev1: /* RFC 2060 */
678 gen_send(sock, "FETCH %d BODY.PEEK[TEXT]", number);
680 gen_send(sock, "FETCH %d BODY[TEXT]", number);
683 case IMAP4: /* RFC 1730 */
685 gen_send(sock, "FETCH %d RFC822.TEXT.PEEK", number);
687 gen_send(sock, "FETCH %d RFC822.TEXT", number);
690 default: /* RFC 1176 */
691 gen_send(sock, "FETCH %d RFC822.TEXT", number);
695 /* looking for FETCH response */
699 if ((ok = gen_recv(sock, buf, sizeof(buf))))
702 (!strstr(buf+4, "FETCH") || sscanf(buf+2, "%d", &num) != 1);
708 * Try to extract a length from the FETCH response. RFC2060 requires
709 * it to be present, but at least one IMAP server (Novell GroupWise)
712 if ((cp = strchr(buf, '{')))
713 *lenp = atoi(cp + 1);
715 *lenp = -1; /* missing length part in FETCH reponse */
720 static int imap_trail(int sock, struct query *ctl, int number)
721 /* discard tail of FETCH response after reading message text */
723 /* expunges change the fetch numbers */
724 /* number -= expunged; */
728 char buf[MSGBUFSIZE+1];
731 if ((ok = gen_recv(sock, buf, sizeof(buf))))
734 /* UW IMAP returns "OK FETCH", Cyrus returns "OK Completed" */
735 if (strstr(buf, "OK"))
740 * Any IMAP server that fails to set Seen on a BODY[TEXT]
741 * fetch violates RFC2060 p.43 (top). This becomes an issue
742 * when keep is on, because seen messages aren't deleted and
743 * get refetched on each poll. As a workaround, if keep is on
744 * we can set the Seen flag explicitly.
746 * This code isn't used yet because we don't know of any IMAP
747 * servers broken in this way.
750 if ((ok = gen_transact(sock,
751 imap_version == IMAP4
752 ? "STORE %d +FLAGS.SILENT (\\Seen)"
753 : "STORE %d +FLAGS (\\Seen)",
756 #endif /* __UNUSED__ */
762 static int imap_delete(int sock, struct query *ctl, int number)
763 /* set delete flag for given message */
767 /* expunges change the fetch numbers */
771 * Use SILENT if possible as a minor throughput optimization.
772 * Note: this has been dropped from IMAP4rev1.
774 * We set Seen because there are some IMAP servers (notably HP
775 * OpenMail) that do message-receipt DSNs, but only when the seen
776 * bit is set. This is the appropriate time -- we get here right
777 * after the local SMTP response that says delivery was
780 if ((ok = gen_transact(sock,
781 imap_version == IMAP4
782 ? "STORE %d +FLAGS.SILENT (\\Seen \\Deleted)"
783 : "STORE %d +FLAGS (\\Seen \\Deleted)",
790 * We do an expunge after expunge_period messages, rather than
791 * just before quit, so that a line hit during a long session
792 * won't result in lots of messages being fetched again during
795 if (NUM_NONZERO(expunge_period) && (deletions % expunge_period) == 0)
796 internal_expunge(sock);
801 static int imap_logout(int sock, struct query *ctl)
802 /* send logout command */
804 /* if any un-expunged deletions remain, ship an expunge now */
806 internal_expunge(sock);
809 /* Memory clean-up */
811 free(unseen_messages);
812 #endif /* USE_SEARCH */
814 return(gen_transact(sock, "LOGOUT"));
817 const static struct method imap =
819 "IMAP", /* Internet Message Access Protocol */
823 #else /* INET6_ENABLE */
824 143, /* standard IMAP2bis/IMAP4 port */
825 993, /* ssl IMAP2bis/IMAP4 port */
826 #endif /* INET6_ENABLE */
827 TRUE, /* this is a tagged protocol */
828 FALSE, /* no message delimiter */
829 imap_ok, /* parse command response */
830 imap_canonicalize, /* deal with embedded slashes and spaces */
831 imap_getauth, /* get authorization */
832 imap_getrange, /* query range of messages */
833 imap_getsizes, /* get sizes of messages (used for ESMTP SIZE option) */
834 imap_is_old, /* no UID check */
835 imap_fetch_headers, /* request given message headers */
836 imap_fetch_body, /* request given message body */
837 imap_trail, /* eat message trailer */
838 imap_delete, /* delete the message */
839 imap_logout, /* expunge and exit */
840 TRUE, /* yes, we can re-poll */
843 int doIMAP(struct query *ctl)
844 /* retrieve messages using IMAP Version 2bis or Version 4 */
846 return(do_protocol(ctl, &imap));
849 /* imap.c ends here */