/* * imap.c -- IMAP2bis/IMAP4 protocol methods * * Copyright 1997 by Eric S. Raymond * For license terms, see the file COPYING in this directory. */ #include "config.h" #include "fetchmail.h" #include #include #include #include #if defined(STDC_HEADERS) #include #include #include #endif #include "socket.h" #include "i18n.h" /* imap_version values */ #define IMAP2 -1 /* IMAP2 or IMAP2BIS, RFC1176 */ #define IMAP4 0 /* IMAP4 rev 0, RFC1730 */ #define IMAP4rev1 1 /* IMAP4 rev 1, RFC2060 */ /* global variables: please reinitialize them explicitly for proper * working in daemon mode */ /* TODO: session variables to be initialized before server greeting */ static int preauth = FALSE; /* session variables initialized in capa_probe() or imap_getauth() */ static char capabilities[MSGBUFSIZE+1]; static int imap_version = IMAP4; static flag has_idle = FALSE; static int expunge_period = 1; static void clear_sessiondata(void) { /* must match defaults above */ preauth = FALSE; memset(capabilities, 0, sizeof(capabilities)); imap_version = IMAP4; has_idle = FALSE; expunge_period = 1; } /* the next ones need to be kept in synch - C89 does not consider strlen() * a const initializer */ const char *const capa_begin = " [CAPABILITY "; const unsigned capa_len = 13; /* mailbox variables initialized in imap_getrange() */ static int count = 0, oldcount = 0, recentcount = 0, unseen = 0, deletions = 0; static unsigned int startcount = 1; static int expunged = 0; static unsigned int *unseen_messages; /* for "IMAP> EXPUNGE" */ static int actual_deletions = 0; /* for "IMAP> IDLE" */ static int saved_timeout = 0, idle_timeout = 0; static time_t idle_start_time = 0; static int imap_setup(struct query *ctl) { (void)ctl; clear_sessiondata(); return PS_SUCCESS; } static int imap_cleanup(struct query *ctl) { (void)ctl; clear_sessiondata(); return PS_SUCCESS; } static void copy_capabilities(const char *buf) { strlcpy(capabilities, buf, sizeof(capabilities)); capabilities[strcspn(capabilities, "]")] = '\0'; /* truncate at ] */ /* UW-IMAP server 10.173 notifies in all caps, but RFC2060 says we should expect a response in mixed-case */ if (strstr(capabilities, "IMAP4REV1")) { imap_version = IMAP4rev1; /* RFC-3501 (2060) */ if (outlevel >= O_DEBUG) report(stdout, GT_("Protocol identified as IMAP4 rev 1\n")); } else if (strstr(capabilities, "IMAP4")) { imap_version = IMAP4; /* RFC-1730 */ if (outlevel >= O_DEBUG) report(stdout, GT_("Protocol identified as IMAP4 rev 0\n")); } else { imap_version = IMAP2; if (outlevel >= O_DEBUG) report(stdout, GT_("Protocol identified as IMAP2 or IMAP2BIS\n")); } /* * Handle idling. We depend on coming through here on startup * and after each timeout (including timeouts during idles). */ if (strstr(capabilities, "IDLE")) has_idle = TRUE; else has_idle = FALSE; if (outlevel >= O_VERBOSE) report(stdout, GT_("will idle after poll\n")); /* FIXME: rename this to can... idle for next release */ peek_capable = (imap_version >= IMAP4); } static int imap_untagged_response(int sock, const char *buf) /* interpret untagged status responses */ { /* For each individual check, use a BLANK before the word to avoid * confusion with the \Recent flag or similar */ if (stage == STAGE_GETAUTH && !strncmp(buf, "* CAPABILITY", 12)) { copy_capabilities(buf + 12); } else if (stage == STAGE_GETAUTH && !strncmp(buf, "* PREAUTH", 9)) { preauth = TRUE; } else if (stage != STAGE_LOGOUT && !strncmp(buf, "* BYE", 5)) { /* log the unexpected bye from server as we expect the * connection to be cut-off after this */ if (outlevel > O_SILENT) report(stderr, GT_("Received BYE response from IMAP server: %s\n"), buf + 5); return PS_SOCKET; /* tell caller to not touch the socket any longer. Note this is under stage != STAGE_LOGOUT, so when we are logging out properly, we will complete the protocol exchange. */ } else if (strstr(buf, " EXISTS")) { char *t; unsigned long u; errno = 0; u = strtoul(buf+2, &t, 10); /* * Don't trust the message count passed by the server. * Without this check, it might be possible to do a * DNS-spoofing attack that would pass back a ridiculous * count, and allocate a malloc area that would overlap * a portion of the stack. */ if (errno /* strtoul failed */ || t == buf+2 /* no valid data */ || u > (unsigned long)(INT_MAX/sizeof(int)) /* too large */) { report(stderr, GT_("bogus message count in \"%s\"!"), buf); return(PS_PROTOCOL); } count = u; /* safe as long as count <= INT_MAX - checked above */ if ((recentcount = count - oldcount) < 0) recentcount = 0; /* * Nasty kluge to handle RFC2177 IDLE. If we know we're idling * we can't wait for the tag matching the IDLE; we have to tell the * server the IDLE is finished by shipping back a DONE when we * see an EXISTS. Only after that will a tagged response be * shipped. The idling flag also gets cleared on a timeout. */ if (stage == STAGE_IDLE) { /* If IDLE isn't supported, we were only sending NOOPs anyway. */ if (has_idle) { /* we do our own write and report here to disable tagging */ SockWrite(sock, "DONE\r\n", 6); if (outlevel >= O_MONITOR) report(stdout, "IMAP> DONE\n"); } mytimeout = saved_timeout; stage = STAGE_GETRANGE; } } /* we now compute recentcount as a difference between * new and old EXISTS, hence disable RECENT check */ # if 0 else if (strstr(buf, " RECENT")) { /* fixme: use strto[u]l and error checking */ recentcount = atoi(buf+2); } # endif else if (strstr(buf, " EXPUNGE")) { unsigned long u; char *t; /* the response "* 10 EXPUNGE" means that the currently * tenth (i.e. only one) message has been deleted */ errno = 0; u = strtoul(buf+2, &t, 10); if (errno /* conversion error */ || t == buf+2 /* no number found */) { report(stderr, GT_("bogus EXPUNGE count in \"%s\"!"), buf); return PS_PROTOCOL; } if (u > 0) { if (count > 0) count--; if (oldcount > 0) oldcount--; /* We do expect an EXISTS response immediately * after this, so this updation of recentcount is * just a precaution! * XXX FIXME: per RFC 3501, 7.4.1. EXPUNGE Reponse * on Page 73, an EXISTS response is not required */ if ((recentcount = count - oldcount) < 0) recentcount = 0; actual_deletions++; } } /* * The server may decide to make the mailbox read-only, * which causes fetchmail to go into a endless loop * fetching the same message over and over again. * * However, for check_only, we use EXAMINE which will * mark the mailbox read-only as per the RFC. * * This checks for the condition and aborts if * the mailbox is read-only. * * See RFC 2060 section 6.3.1 (SELECT). * See RFC 2060 section 6.3.2 (EXAMINE). */ else if (stage == STAGE_GETRANGE && !check_only && strstr(buf, "[READ-ONLY]")) { return(PS_LOCKBUSY); } else { return(PS_UNTAGGED); } return(PS_SUCCESS); } static int imap_response(int sock, char *argbuf, struct RecvSplit *rs) /* parse command response */ { char buf[MSGBUFSIZE+1]; char *tmp; do { int ok; char *cp; if (rs) ok = gen_recv_split(sock, buf, sizeof(buf), rs); else ok = gen_recv(sock, buf, sizeof(buf)); if (ok != PS_SUCCESS) return(ok); /* all tokens in responses are caseblind */ for (cp = buf; *cp; cp++) if (islower((unsigned char)*cp)) *cp = toupper((unsigned char)*cp); /* FIXME: does not look for or handle command continuation requests, * i. e. the token "+" instead of tag or "*" */ /* untagged responses start with "* " */ if (buf[0] == '*' && buf[1] == ' ') { ok = imap_untagged_response(sock, buf); if (ok == PS_UNTAGGED) { if (argbuf && stage != STAGE_IDLE && tag[0] != '\0') { /* if there is an unmatched response, pass it back to * the calling function for further analysis. The * calling function should call imap_response() again * to read the remaining response */ strcpy(argbuf, buf); return(ok); } } else if (ok != PS_SUCCESS) return(ok); } /* on login, the server may volunteer new CAPABILITY information * with the tagged OK response, record it */ /* WARNING: this must match with what's in imap_getauth()! */ if (stage == STAGE_GETAUTH && (tmp = strstr(buf, capa_begin))) { copy_capabilities(tmp + capa_len); if (outlevel >= O_DEBUG) { report(stdout, GT_("found updated capabilities list\n")); } } if (stage == STAGE_IDLE) { /* reduce the timeout: servers may not reset their timeout * when they send some information asynchronously */ mytimeout = idle_timeout - (time((time_t *) NULL) - idle_start_time); if (mytimeout <= 0) return(PS_IDLETIMEOUT); } } while (tag[0] != '\0' && strncmp(buf, tag, strlen(tag))); if (tag[0] == '\0') { if (argbuf) strcpy(argbuf, buf); return(PS_SUCCESS); } else { char *cp; /* skip the tag */ for (cp = buf; !isspace((unsigned char)*cp); cp++) continue; while (isspace((unsigned char)*cp)) cp++; if (strncasecmp(cp, "OK", 2) == 0) { if (argbuf) strcpy(argbuf, cp); return(PS_SUCCESS); } else if (strncasecmp(cp, "BAD", 3) == 0) return(PS_ERROR); else if (strncasecmp(cp, "NO", 2) == 0) { if (stage == STAGE_GETAUTH) return(PS_AUTHFAIL); /* RFC2060, 6.2.2 */ else if (stage == STAGE_GETSIZES) return(PS_SUCCESS); /* see comments in imap_getpartialsizes() */ else return(PS_ERROR); } else return(PS_PROTOCOL); } } static int imap_ok(int sock, char *argbuf) /* parse command response */ { int ok; while ((ok = imap_response(sock, argbuf, NULL)) == PS_UNTAGGED) ; /* wait for the tagged response */ return(ok); } #ifdef NTLM_ENABLE #include "ntlm.h" /* * NTLM support by Grant Edwards. * * Handle MS-Exchange NTLM authentication method. This is the same * as the NTLM auth used by Samba for SMB related services. We just * encode the packets in base64 instead of sending them out via a * network interface. * * Much source (ntlm.h, smb*.c smb*.h) was borrowed from Samba. */ static int do_imap_ntlm(int sock, struct query *ctl) { int result; gen_send(sock, "AUTHENTICATE NTLM"); if ((result = ntlm_helper(sock, ctl, "IMAP"))) return result; result = imap_ok (sock, NULL); if (result == PS_SUCCESS) return PS_SUCCESS; else return PS_AUTHFAIL; } #endif /* NTLM */ static void imap_canonicalize(char *result, char *raw, size_t maxlen) /* encode an IMAP password as per RFC1730's quoting conventions */ { size_t i, j; j = 0; for (i = 0; i < strlen(raw) && i < maxlen; i++) { if ((raw[i] == '\\') || (raw[i] == '"')) result[j++] = '\\'; result[j++] = raw[i]; } result[j] = '\0'; } static int capa_probe(int sock, struct query *ctl) /* set capability variables from a CAPA probe */ { int err; (void)ctl; /* probe to see if we're running IMAP4 and can use RFC822.PEEK */ memset(capabilities, 0, sizeof capabilities); err = gen_transact(sock, "CAPABILITY"); /* if successful, copy_capabilities() will have handled it */ if (err == PS_ERROR) { /* this is OK for IMAP2 which did not support a CAPABILITY command */ err = PS_SUCCESS; } return err; } static int do_auth_external (int sock, const char *command, const char *name) /* do authentication "external" (authentication provided by client cert) */ { /* FIXME: not compliant with RFC 4422 (SASL) without RFC 4959 (SASL-IR)- * does not support the usual server challenge/response */ char buf[256]; if (!strstr(capabilities, "SASL-IR")) { report(stderr, GT_("server did not advertise SASL-IR extension but fetchmail's implementation requires it for AUTHENTICATE EXTERNAL\n")); return PS_AUTHFAIL; } if (name && name[0]) { size_t len = strlen(name); if (len64frombits(len) + 1 <= sizeof(buf)) /* +1: need to fit \0 byte */ to64frombits (buf, name, strlen(name), sizeof buf); else return PS_AUTHFAIL; /* buffer too small. */ } else { strcpy(buf, "="); } return gen_transact(sock, "%s EXTERNAL %s",command,buf); } /** apply for connection authorization, possibly executing STARTTLS */ static int imap_getauth(int sock, struct query *ctl, char *greeting) { int ok = 0; char *commonname; /* * Assumption: expunges are cheap, so we want to do them * after every message unless user said otherwise. */ if (NUM_SPECIFIED(ctl->expunge)) expunge_period = NUM_VALUE_OUT(ctl->expunge); else expunge_period = 1; /* check if imap_ok() has already parsed CAPABILITY from the greeting when * driver.c ran it on the server's greeting message - note this must match * with what's in imap_response()! */ if (!strstr(greeting, capa_begin)) { int err = capa_probe(sock, ctl); if (err) return err; } commonname = ctl->server.pollname; if (ctl->server.via) commonname = ctl->server.via; if (ctl->sslcommonname) commonname = ctl->sslcommonname; #ifdef SSL_ENABLE /* Defend against a PREAUTH-prevents-STARTTLS attack */ if (preauth && must_starttls(ctl)) { if (ctl->server.plugin && A_SSH == ctl->server.authenticate) { report(stderr, GT_("%s: configuration requires TLS, but STARTTLS is not permitted " "because of authenticated state (PREAUTH). Aborting connection. If your plugin is secure, you can defeat STARTTLS with --sslproto '' (see manual).\n"), commonname); } else { report(stderr, GT_("%s: configuration requires TLS, but STARTTLS is not permitted " "because of authenticated state (PREAUTH). Aborting connection. Server permitting, try --ssl instead (see manual).\n"), commonname); } preauth = FALSE; /* reset for the next session */ return PS_SOCKET; } if (maybe_starttls(ctl)) { if ((strstr(capabilities, "STARTTLS") && maybe_starttls(ctl)) || must_starttls(ctl)) /* if TLS is mandatory, ignore capabilities */ { /* Don't need to worry whether TLS is mandatory or * opportunistic unless SSLOpen() fails (see below). */ if (gen_transact(sock, "STARTTLS") == PS_SUCCESS && (set_timeout(mytimeout), SSLOpen(sock, ctl->sslcert, ctl->sslkey, ctl->sslproto, ctl->sslcertck, ctl->sslcertfile, ctl->sslcertpath, ctl->sslfingerprint, commonname, ctl->server.pollname, &ctl->remotename)) != -1) { if (outlevel >= O_VERBOSE) { report(stdout, GT_("%s: upgrade to TLS succeeded.\n"), commonname); } /* * RFC 2595 says this: * * "Once TLS has been started, the client MUST discard cached * information about server capabilities and SHOULD re-issue the * CAPABILITY command. This is necessary to protect against * man-in-the-middle attacks which alter the capabilities list prior * to STARTTLS. The server MAY advertise different capabilities * after STARTTLS." * * Now that we're confident in our TLS connection we can * guarantee a secure capability re-probe. */ clear_sessiondata(); if ((ok = capa_probe(sock, ctl))) { return ok; } } else if (must_starttls(ctl)) { /* Config required TLS but we couldn't guarantee it, so we must * stop. */ set_timeout(0); report(stderr, GT_("%s: upgrade to TLS failed.\n"), commonname); return PS_SOCKET; } else { set_timeout(0); if (outlevel >= O_VERBOSE) { report(stdout, GT_("%s: opportunistic upgrade to TLS failed, trying to continue\n"), commonname); } /* We don't know whether the connection is in a working state, so * test by issuing a NOOP. */ if (gen_transact(sock, "NOOP") != PS_SUCCESS) { /* Not usable. Empty sslproto to force an unencrypted * connection on the next attempt, and repoll. */ ctl->sslproto = xstrdup(""); return PS_REPOLL; } /* Usable. Proceed with authenticating insecurely. */ } } } else { if (strstr(capabilities, "STARTTLS") && outlevel >= O_VERBOSE) { report(stdout, GT_("%s: WARNING: server offered STARTTLS but sslproto '' given.\n"), commonname); } } #endif /* SSL_ENABLE */ /* * If either (a) we saw a PREAUTH token in the greeting, or * (b) the user specified ssh preauthentication, then we're done. */ if (preauth || ctl->server.authenticate == A_SSH) { preauth = FALSE; /* reset for the next session */ return(PS_SUCCESS); } /* * Time to authenticate the user. * Try the protocol variants that don't require passwords first. */ ok = PS_AUTHFAIL; /* formally, never read, but let's leave this in place as a safe default for future maintenance */ (void)ok; /* Yahoo hack - we'll just try ID if it was offered by the server, * and IGNORE errors. */ { char *tmp = strstr(capabilities, " ID"); if (tmp && !isalnum((unsigned char)tmp[3]) && strstr(ctl->server.via ? ctl->server.via : ctl->server.pollname, "yahoo.com")) { (void)gen_transact(sock, "ID (\"guid\" \"1\")"); } } if (ctl->server.authenticate == A_ANY || ctl->server.authenticate == A_EXTERNAL) { if (!strstr(capabilities, "AUTH=EXTERNAL")) { if (ctl->server.authenticate == A_EXTERNAL) { report(stderr, GT_("%s: --auth external requested but server does not advertise it.\n"), commonname); return PS_AUTHFAIL; } } else { int err = do_auth_external(sock, "AUTHENTICATE", ctl->remotename); if (err) { if (ctl->server.authenticate != A_ANY) return err; } else { return PS_SUCCESS; } } } #ifdef GSSAPI if (((ctl->server.authenticate == A_ANY && check_gss_creds("imap", ctl->server.truename) == PS_SUCCESS) || ctl->server.authenticate == A_GSSAPI) && strstr(capabilities, "AUTH=GSSAPI")) { if ((ok = do_gssauth(sock, "AUTHENTICATE", "imap", ctl->server.truename, ctl->remotename))) { if (ctl->server.authenticate != A_ANY) return ok; } else { return ok; } } #endif /* GSSAPI */ #ifdef KERBEROS_V4 if ((ctl->server.authenticate == A_ANY || ctl->server.authenticate == A_KERBEROS_V4 || ctl->server.authenticate == A_KERBEROS_V5) && strstr(capabilities, "AUTH=KERBEROS_V4")) { if ((ok = do_rfc1731(sock, "AUTHENTICATE", ctl->server.truename))) { /* SASL cancellation of authentication */ gen_send(sock, "*"); if(ctl->server.authenticate != A_ANY) return ok; } else return ok; } #endif /* KERBEROS_V4 */ /* * No such luck. OK, now try the variants that mask your password * in a challenge-response. */ if ((ctl->server.authenticate == A_ANY && strstr(capabilities, "AUTH=CRAM-MD5")) || ctl->server.authenticate == A_CRAM_MD5) { if ((ok = do_cram_md5 (sock, "AUTHENTICATE", ctl, NULL))) { if(ctl->server.authenticate != A_ANY) return ok; } else return ok; } #ifdef OPIE_ENABLE if ((ctl->server.authenticate == A_ANY || ctl->server.authenticate == A_OTP) && strstr(capabilities, "AUTH=X-OTP")) { if ((ok = do_otp(sock, "AUTHENTICATE", ctl))) { /* SASL cancellation of authentication */ gen_send(sock, "*"); if(ctl->server.authenticate != A_ANY) return ok; } else { return ok; } } #else if (ctl->server.authenticate == A_OTP) { report(stderr, GT_("Required OTP capability not compiled into fetchmail\n")); } #endif /* OPIE_ENABLE */ #ifdef NTLM_ENABLE if ((ctl->server.authenticate == A_ANY || ctl->server.authenticate == A_NTLM) && strstr (capabilities, "AUTH=NTLM")) { if ((ok = do_imap_ntlm(sock, ctl))) { if(ctl->server.authenticate != A_ANY) return ok; } else return(ok); } #else if (ctl->server.authenticate == A_NTLM) { report(stderr, GT_("Required NTLM capability not compiled into fetchmail\n")); } #endif /* NTLM_ENABLE */ /* * We're stuck with sending the password en clair. * Older fetchmail versions permitted overriding LOGINDISABLED, documenting * that it still works on some servers, but 6.4.22 disables this. */ if (ctl->server.authenticate == A_ANY || ctl->server.authenticate == A_PASSWORD) { if (strstr(capabilities, "LOGINDISABLED")) { if (ctl->server.authenticate == A_PASSWORD) { report(stderr, GT_("%s: --auth password requested but server forbids it (LOGINDISABLED).\n"), commonname); return PS_AUTHFAIL; } } else { /* these sizes guarantee no buffer overflow */ static char *remotename, *password; /* XXX FIXME: not thread-safe but dynamic buffer is leaky on timeout */ size_t rnl, pwl; rnl = 2 * strlen(ctl->remotename) + 1; pwl = 2 * strlen(ctl->password) + 1; if (remotename) xfree(remotename); remotename = (char *)xmalloc(rnl); if (password) xfree(password); password = (char *)xmalloc(pwl); imap_canonicalize(remotename, ctl->remotename, rnl); imap_canonicalize(password, ctl->password, pwl); snprintf(shroud, sizeof (shroud), "\"%s\"", password); ok = gen_transact(sock, "LOGIN \"%s\" \"%s\"", remotename, password); memset(shroud, 0x55, sizeof(shroud)); shroud[0] = '\0'; memset(password, 0x55, strlen(password)); xfree(password); xfree(remotename); return ok; /* this assumes that password is the last authentication method to try */ } } /* if we're here, we've run out of authentication methods */ report(stderr, GT_("%s: we've run out of authentication methods and cannot log in.\n"), commonname); return PS_AUTHFAIL; } static int internal_expunge(int sock) /* ship an expunge, resetting associated counters */ { int ok; actual_deletions = 0; if ((ok = gen_transact(sock, "EXPUNGE"))) return(ok); /* if there is a mismatch between the number of mails which should * have been expunged and the number of mails actually expunged, * another email client may be deleting mails. Quit here, * otherwise fetchmail gets out-of-sync with the imap server, * reports the wrong size to the SMTP server on MAIL FROM: and * triggers a "message ... was not the expected length" error on * every subsequent mail */ if (deletions > 0 && deletions != actual_deletions) { report(stderr, GT_("mail expunge mismatch (%d actual != %d expected)\n"), actual_deletions, deletions); deletions = 0; return(PS_ERROR); } expunged += deletions; deletions = 0; #ifdef IMAP_UID /* not used */ expunge_uids(ctl); #endif /* IMAP_UID */ return(PS_SUCCESS); } static int imap_idle(int sock) /* start an RFC2177 IDLE, or fake one if unsupported */ { int ok; saved_timeout = mytimeout; if (has_idle) { /* special timeout to terminate the IDLE and re-issue it * at least every 28 minutes: * (the server may have an inactivity timeout) */ mytimeout = idle_timeout = 1680; /* 28 min */ time(&idle_start_time); stage = STAGE_IDLE; /* enter IDLE mode */ ok = gen_transact(sock, "IDLE"); if (ok == PS_IDLETIMEOUT) { /* send "DONE" continuation */ SockWrite(sock, "DONE\r\n", 6); if (outlevel >= O_MONITOR) report(stdout, "IMAP> DONE\n"); /* reset stage and timeout here: we are not idling any more */ mytimeout = saved_timeout; stage = STAGE_GETRANGE; /* get OK IDLE message */ ok = imap_ok(sock, NULL); } } else { /* no idle support, fake it */ /* Note: stage and timeout have not been changed here as NOOP * does not idle */ ok = gen_transact(sock, "NOOP"); /* no error, but no new mail either */ if (ok == PS_SUCCESS && recentcount == 0) { /* There are some servers who do send new mail * notification out of the blue. This is in compliance * with RFC 2060 section 5.3. Wait for that with a low * timeout */ mytimeout = idle_timeout = 28; time(&idle_start_time); stage = STAGE_IDLE; /* We are waiting for notification; no tag needed */ tag[0] = '\0'; /* wait (briefly) for an unsolicited status update */ ok = imap_ok(sock, NULL); if (ok == PS_IDLETIMEOUT) { /* no notification came; ok */ ok = PS_SUCCESS; } } } /* restore normal timeout value */ set_timeout(0); mytimeout = saved_timeout; stage = STAGE_GETRANGE; return(ok); } static int imap_search(int sock, struct query *ctl, int count) /* search for unseen messages */ { int ok; char buf[MSGBUFSIZE+1], *cp; /* Don't count deleted messages. Enabled only for IMAP4 servers or * higher and only when keeping mails. This flag will have an * effect only when user has marked some unread mails for deletion * using another e-mail client. */ flag skipdeleted = (imap_version >= IMAP4) && ctl->keep; const char *undeleted; /* structure to keep the end portion of the incomplete response */ struct RecvSplit rs; /* startcount is higher than count so that if there are no * unseen messages, imap_getsizes() will not need to do * anything! */ startcount = count + 1; for (;;) { undeleted = (skipdeleted ? " UNDELETED" : ""); gen_send(sock, "SEARCH UNSEEN%s", undeleted); gen_recv_split_init("* SEARCH", &rs); while ((ok = imap_response(sock, buf, &rs)) == PS_UNTAGGED) { if ((cp = strstr(buf, "* SEARCH"))) { char *ep; cp += 8; /* skip "* SEARCH" */ while (*cp && unseen < count) { /* skip whitespace */ while (*cp && isspace((unsigned char)*cp)) cp++; if (*cp) { unsigned long um; errno = 0; um = strtoul(cp,&ep,10); if (errno == 0 && ep > cp && um <= INT_MAX && um <= (unsigned)count) { unseen_messages[unseen++] = um; if (outlevel >= O_DEBUG) report(stdout, GT_("%lu is unseen\n"), um); if (startcount > um) startcount = um; } cp = ep; } } } } if (ok != PS_ERROR) /* success or non-protocol error */ return(ok); /* there is a protocol error. try a different search command. */ if (skipdeleted) { /* retry with "SEARCH UNSEEN" */ skipdeleted = FALSE; continue; } /* try with "FETCH 1:n FLAGS" */ break; } if (count == 1) gen_send(sock, "FETCH %d FLAGS", count); else gen_send(sock, "FETCH %d:%d FLAGS", 1, count); while ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED) { unsigned int num; int consumed; /* expected response format: * IMAP< * 1 FETCH (FLAGS (\Seen)) * IMAP< * 2 FETCH (FLAGS (\Seen \Deleted)) * IMAP< * 3 FETCH (FLAGS ()) * IMAP< * 4 FETCH (FLAGS (\Recent)) * IMAP< * 5 FETCH (UID 10 FLAGS (\Recent)) */ if (unseen < count && sscanf(buf, "* %u %n", &num, &consumed) == 1 && 0 == strncasecmp(buf+consumed, "FETCH", 5) && isspace((unsigned char)buf[consumed+5]) && num >= 1 && num <= (unsigned)count && strstr(buf, "FLAGS ") && !strstr(buf, "\\SEEN") && !strstr(buf, "\\DELETED")) { unseen_messages[unseen++] = num; if (outlevel >= O_DEBUG) report(stdout, GT_("%u is unseen\n"), num); if (startcount > num) startcount = num; } } return(ok); } static int imap_getrange(int sock, struct query *ctl, const char *folder, int *countp, int *newp, int *bytes) /* get range of messages to be fetched */ { int ok; /* find out how many messages are waiting */ *bytes = -1; if (pass > 1) { /* deleted mails have already been expunged by * end_mailbox_poll(). * * recentcount is already set here by the last imap command which * returned EXISTS on detecting new mail. if recentcount is 0, wait * for new mail. * * this is a while loop because imap_idle() might return on other * mailbox changes also */ while (recentcount == 0 && ctl->idle && has_idle) { smtp_close(ctl, 1); ok = imap_idle(sock); if (ok) { report(stderr, GT_("re-poll failed\n")); return(ok); } } /* if recentcount is 0, return no mail */ if (recentcount == 0) count = 0; if (outlevel >= O_DEBUG) report(stdout, ngettext("%d message waiting after re-poll\n", "%d messages waiting after re-poll\n", count), count); } else { oldcount = count = 0; ok = gen_transact(sock, check_only ? "EXAMINE \"%s\"" : "SELECT \"%s\"", folder ? folder : "INBOX"); /* imap_ok returns PS_LOCKBUSY for READ-ONLY folders, * which we can safely use in fetchall keep only */ if (ok == PS_LOCKBUSY && ctl->fetchall && ctl-> keep) ok = 0; if (ok != 0) { report(stderr, GT_("mailbox selection failed\n")); return(ok); } else if (outlevel >= O_DEBUG) report(stdout, ngettext("%d message waiting after first poll\n", "%d messages waiting after first poll\n", count), count); /* * We should have an expunge here to * a) avoid fetching deleted mails during 'fetchall' * b) getting a wrong count of mails during 'no fetchall' */ if (!check_only && !ctl->keep && count > 0) { ok = internal_expunge(sock); if (ok) { report(stderr, GT_("expunge failed\n")); return(ok); } if (outlevel >= O_DEBUG) report(stdout, ngettext("%d message waiting after expunge\n", "%d messages waiting after expunge\n", count), count); } if (count == 0 && ctl->idle && has_idle) { /* no messages? then we may need to idle until we get some */ while (count == 0) { ok = imap_idle(sock); if (ok) { report(stderr, GT_("re-poll failed\n")); return(ok); } } if (outlevel >= O_DEBUG) report(stdout, ngettext("%d message waiting after re-poll\n", "%d messages waiting after re-poll\n", count), count); } } *countp = oldcount = count; recentcount = 0; startcount = 1; /* OK, now get a count of unseen messages and their indices */ if (!ctl->fetchall && count > 0) { if (unseen_messages) free(unseen_messages); unseen_messages = (unsigned int *)xmalloc(count * sizeof(unsigned int)); memset(unseen_messages, 0, count * sizeof(unsigned int)); unseen = 0; ok = imap_search(sock, ctl, count); if (ok != 0) { report(stderr, GT_("search for unseen messages failed\n")); return(ok); } if (outlevel >= O_DEBUG && unseen > 0) report(stdout, GT_("%u is first unseen\n"), startcount); } else unseen = -1; *newp = unseen; expunged = 0; deletions = 0; return(PS_SUCCESS); } static int imap_getpartialsizes(int sock, int first, int last, int *sizes) /* capture the sizes of messages #first-#last */ { char buf [MSGBUFSIZE+1]; int ok; /* * Some servers (as in, PMDF5.1-9.1 under OpenVMS 6.1) * won't accept 1:1 as valid set syntax. Some implementors * should be taken out and shot for excessive anality. * * Microsoft Exchange (brain-dead piece of crap that it is) * sometimes gets its knickers in a knot about bodiless messages. * You may see responses like this: * * fetchmail: IMAP> A0004 FETCH 1:9 RFC822.SIZE * fetchmail: IMAP< * 2 FETCH (RFC822.SIZE 1187) * fetchmail: IMAP< * 3 FETCH (RFC822.SIZE 3954) * fetchmail: IMAP< * 4 FETCH (RFC822.SIZE 1944) * fetchmail: IMAP< * 5 FETCH (RFC822.SIZE 2933) * fetchmail: IMAP< * 6 FETCH (RFC822.SIZE 1854) * fetchmail: IMAP< * 7 FETCH (RFC822.SIZE 34054) * fetchmail: IMAP< * 8 FETCH (RFC822.SIZE 5561) * fetchmail: IMAP< * 9 FETCH (RFC822.SIZE 1101) * fetchmail: IMAP< A0004 NO The requested item could not be found. * * This means message 1 has only headers. For kicks and grins * you can telnet in and look: * A003 FETCH 1 FULL * A003 NO The requested item could not be found. * A004 fetch 1 rfc822.header * A004 NO The requested item could not be found. * A006 FETCH 1 BODY * * 1 FETCH (BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 35 3)) * A006 OK FETCH completed. * * To get around this, we treat the final NO as success and count * on the fact that the sizes array has been preinitialized with a * known-bad size value. */ /* expunges change the fetch numbers */ first -= expunged; last -= expunged; if (last == first) gen_send(sock, "FETCH %d RFC822.SIZE", last); else if (last > first) gen_send(sock, "FETCH %d:%d RFC822.SIZE", first, last); else /* no unseen messages! */ return(PS_SUCCESS); while ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED) { unsigned int size; int num; int consumed; char *ptr; /* expected response formats: * IMAP> A0005 FETCH 1 RFC822.SIZE * IMAP< * 1 FETCH (RFC822.SIZE 1187) * IMAP< * 1 FETCH (UID 16 RFC822.SIZE 1447) */ if (sscanf(buf, "* %d %n", &num, &consumed) == 1 && 0 == strncasecmp(buf + consumed, "FETCH", 5) && isspace((unsigned char)buf[consumed + 5]) && (ptr = strstr(buf, "RFC822.SIZE ")) && sscanf(ptr, "RFC822.SIZE %u", &size) == 1) { if (num >= first && num <= last) sizes[num - first] = size; else report(stderr, GT_("Warning: ignoring bogus data for message sizes returned by the server.\n")); } } return(ok); } static int imap_getsizes(int sock, int count, int *sizes) /* capture the sizes of all messages */ { return imap_getpartialsizes(sock, 1, count, sizes); } static int imap_is_old(int sock, struct query *ctl, int number) /* is the given message old? */ { flag seen = TRUE; int i; (void)sock; (void)ctl; /* * Expunges change the fetch numbers, but unseen_messages contains * indices from before any expungees were done. So neither the * argument nor the values in message_sequence need to be decremented. */ seen = TRUE; for (i = 0; i < unseen; i++) if (unseen_messages[i] == (unsigned)number) { seen = FALSE; break; } return(seen); } #if 0 static char *skip_token(char *ptr) { while(isspace((unsigned char)*ptr)) ptr++; while(!isspace((unsigned char)*ptr) && !iscntrl((unsigned char)*ptr)) ptr++; while(isspace((unsigned char)*ptr)) ptr++; return(ptr); } #endif static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp) /* request headers of nth message */ { char buf [MSGBUFSIZE+1]; int num; int ok; char *ptr; (void)ctl; /* expunges change the fetch numbers */ number -= expunged; /* * This is blessed by RFC1176, RFC1730, RFC2060. * According to the RFCs, it should *not* set the \Seen flag. */ gen_send(sock, "FETCH %d RFC822.HEADER", number); /* looking for FETCH response */ if ((ok = imap_response(sock, buf, NULL)) == PS_UNTAGGED) { int consumed; /* expected response formats: * IMAP> A0006 FETCH 1 RFC822.HEADER * IMAP< * 1 FETCH (RFC822.HEADER {1360} * IMAP< * 1 FETCH (UID 16 RFC822.HEADER {1360} * IMAP< * 1 FETCH (UID 16 RFC822.SIZE 4029 RFC822.HEADER {1360} */ if (sscanf(buf, "* %d %n", &num, &consumed) == 1 && 0 == strncasecmp(buf + consumed, "FETCH", 5) && isspace((unsigned char)buf[5+consumed]) && num == number && (ptr = strstr(buf, "RFC822.HEADER")) && sscanf(ptr, "RFC822.HEADER {%d}%n", lenp, &consumed) == 1 && ptr[consumed-1] == '}') { return(PS_SUCCESS); } /* wait for a tagged response */ imap_ok (sock, 0); /* try to recover for some responses */ if (!strncmp(buf, "* NO", 4) || !strncmp(buf, "* BAD", 5) || strstr(buf, "FETCH ()")) { return(PS_TRANSIENT); } /* a response which does not match any of the above */ if (outlevel > O_SILENT) report(stderr, GT_("Incorrect FETCH response: %s.\n"), buf); return(PS_ERROR); } else if (ok == PS_SUCCESS) { /* an unexpected tagged response */ if (outlevel > O_SILENT) report(stderr, GT_("Incorrect FETCH response: %s.\n"), buf); return(PS_TRANSIENT); } return(ok); } static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp) /* request body of nth message */ { char buf [MSGBUFSIZE+1], *cp; int num; (void)ctl; /* expunges change the fetch numbers */ number -= expunged; /* * If we're using IMAP4, we can fetch the message without setting its * seen flag. This is good! It means that if the protocol exchange * craps out during the message, it will still be marked `unseen' on * the server. * * According to RFC2060, and Mark Crispin the IMAP maintainer, * FETCH %d BODY[TEXT] and RFC822.TEXT are "functionally * equivalent". However, we know of at least one server that * treats them differently in the presence of MIME attachments; * the latter form downloads the attachment, the former does not. * The server is InterChange, and the fool who implemented this * misfeature ought to be strung up by his thumbs. * * When I tried working around this by disabling use of the 4rev1 form, * I found that doing this breaks operation with M$ Exchange. * Annoyingly enough, Exchange's refusal to cope is technically legal * under RFC2062. Trust Microsoft, the Great Enemy of interoperability * standards, to find a way to make standards compliance irritating.... */ switch (imap_version) { case IMAP4rev1: /* RFC 2060 */ gen_send(sock, "FETCH %d BODY.PEEK[TEXT]", number); break; case IMAP4: /* RFC 1730 */ gen_send(sock, "FETCH %d RFC822.TEXT.PEEK", number); break; default: /* RFC 1176 */ gen_send(sock, "FETCH %d RFC822.TEXT", number); break; } /* looking for FETCH response */ do { int ok; if ((ok = gen_recv(sock, buf, sizeof(buf)))) return(ok); } while (!strstr(buf+4, "FETCH") || sscanf(buf+2, "%d", &num) != 1); if (num != number) return(PS_ERROR); /* Understand "NIL" as length => no body present * (MS Exchange, BerliOS Bug #11980) */ if (strstr(buf+10, "NIL)")) { *lenp = 0; return PS_SUCCESS; } /* Understand the empty string. Seen on Yahoo. */ /* XXX FIXME: we should be able to handle strings here. */ if (strstr(buf+10, "\"\")")) { *lenp = 0; return PS_SUCCESS; } /* * Try to extract a length from the FETCH response. RFC2060 requires * it to be present, but at least one IMAP server (Novell GroupWise) * botches this. The overflow check is needed because of a broken * server called dbmail that returns huge garbage lengths. */ if ((cp = strchr(buf, '{'))) { long l; char *t; errno = 0; ++ cp; l = strtol(cp, &t, 10); if (errno || t == cp || (t && !strchr(t, '}')) /* parse error */ || l < 0 || l > INT_MAX /* range check */) { *lenp = -1; } else { *lenp = l; } } else { *lenp = -1; /* missing length part in FETCH reponse */ } return PS_SUCCESS; } static int imap_trail(int sock, struct query *ctl, const char *tag) /* discard tail of FETCH response after reading message text */ { /* expunges change the fetch numbers */ /* number -= expunged; */ (void)ctl; (void)tag; return imap_ok(sock, NULL); } static int imap_delete(int sock, struct query *ctl, int number) /* set delete flag for given message */ { int ok; /* Select which flags to set on message deletion: */ static const char delflags[] = "\\Seen \\Deleted"; (void)ctl; /* expunges change the fetch numbers */ number -= expunged; /* * Use SILENT if possible as a minor throughput optimization. * Note: this has been dropped from IMAP4rev1. * * We set \Seen because there are some IMAP servers (notably HP * OpenMail and MS Exchange) do message-receipt DSNs, * but only when the seen bit gets set. * This is the appropriate time -- we get here right * after the local SMTP response that says delivery was * successful. */ if ((ok = gen_transact(sock, imap_version == IMAP4 ? "STORE %d +FLAGS.SILENT (%s)" : "STORE %d +FLAGS (%s)", number, delflags))) return(ok); else deletions++; /* * We do an expunge after expunge_period messages, rather than * just before quit, so that a line hit during a long session * won't result in lots of messages being fetched again during * the next session. */ if (NUM_NONZERO(expunge_period) && (deletions % expunge_period) == 0) { if ((ok = internal_expunge(sock))) return(ok); } return(PS_SUCCESS); } static int imap_mark_seen(int sock, struct query *ctl, int number) /* mark the given message as seen */ { (void)ctl; /* expunges change the message numbers */ number -= expunged; return(gen_transact(sock, imap_version == IMAP4 ? "STORE %d +FLAGS.SILENT (\\Seen)" : "STORE %d +FLAGS (\\Seen)", number)); } static int imap_end_mailbox_poll(int sock, struct query *ctl) /* cleanup mailbox before we idle or switch to another one */ { (void)ctl; if (deletions) internal_expunge(sock); return(PS_SUCCESS); } static int imap_logout(int sock, struct query *ctl) /* send logout command */ { (void)ctl; /* if any un-expunged deletions remain, ship an expunge now */ if (deletions) internal_expunge(sock); #ifdef USE_SEARCH /* Memory clean-up */ if (unseen_messages) free(unseen_messages); #endif /* USE_SEARCH */ return(gen_transact(sock, "LOGOUT")); } static const struct method imap = { "IMAP", /* Internet Message Access Protocol */ "imap", /* service (plain and TLS) */ "imaps", /* service (SSL) */ TRUE, /* this is a tagged protocol */ FALSE, /* no message delimiter */ imap_ok, /* parse command response */ imap_getauth, /* get authorization */ imap_getrange, /* query range of messages */ imap_getsizes, /* get sizes of messages (used for ESMTP SIZE option) */ imap_getpartialsizes, /* get sizes of subset of messages (used for ESMTP SIZE option) */ imap_is_old, /* no UID check */ imap_fetch_headers, /* request given message headers */ imap_fetch_body, /* request given message body */ imap_trail, /* eat message trailer */ imap_delete, /* delete the message */ imap_mark_seen, /* how to mark a message as seen */ imap_end_mailbox_poll, /* end-of-mailbox processing */ imap_logout, /* expunge and exit */ TRUE, /* yes, we can re-poll */ imap_setup, /* setup method */ imap_cleanup /* cleanup method */ }; int doIMAP(struct query *ctl) /* retrieve messages using IMAP Version 2bis or Version 4 */ { return(do_protocol(ctl, &imap)); } /* imap.c ends here */