/*
* pop3.c -- POP3 protocol methods
*
* Copyright 1998 by Eric S. Raymond.
* For license terms, see the file COPYING in this directory.
*/
#include "config.h"
#ifdef POP3_ENABLE
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if defined(STDC_HEADERS)
#include <stdlib.h>
#endif
#include "fetchmail.h"
#include "socket.h"
#include "i18n.h"
#if OPIE_ENABLE
#include <opie.h>
#endif /* OPIE_ENABLE */
#ifndef strstr /* glibc-2.1 declares this as a macro */
extern char *strstr(); /* needed on sysV68 R3V7.1. */
#endif /* strstr */
static int last;
#ifdef SDPS_ENABLE
char *sdps_envfrom;
char *sdps_envto;
#endif /* SDPS_ENABLE */
#if OPIE_ENABLE
static char lastok[POPBUFSIZE+1];
#endif /* OPIE_ENABLE */
#define DOTLINE(s) (s[0] == '.' && (s[1]=='\r'||s[1]=='\n'||s[1]=='\0'))
static int pop3_ok (int sock, char *argbuf)
/* parse command response */
{
int ok;
char buf [POPBUFSIZE+1];
char *bufp;
if ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{ bufp = buf;
if (*bufp == '+' || *bufp == '-')
bufp++;
else
return(PS_PROTOCOL);
while (isalpha(*bufp))
bufp++;
if (*bufp)
*(bufp++) = '\0';
if (strcmp(buf,"+OK") == 0)
{
#if OPIE_ENABLE
strcpy(lastok, bufp);
#endif /* OPIE_ENABLE */
ok = 0;
}
else if (strncmp(buf,"-ERR", 4) == 0)
{
if (stage > STAGE_GETAUTH)
ok = PS_PROTOCOL;
/*
* We're checking for "lock busy", "unable to lock",
* "already locked", "wait a few minutes" etc. here.
* This indicates that we have to wait for the server to
* unwedge itself before we can poll again.
*
* PS_LOCKBUSY check empirically verified with two recent
* versions of the Berkeley popper; QPOP (version 2.2) and
* QUALCOMM Pop server derived from UCB (version 2.1.4-R3)
* These are caught by the case-indifferent "lock" check.
* The "wait" catches "mail storage services unavailable,
* wait a few minutes and try again" on the InterMail server.
*
* If these aren't picked up on correctly, fetchmail will
* think there is an authentication failure and wedge the
* connection in order to prevent futile polls.
*
* Gad, what a kluge.
*/
else if (strstr(bufp,"lock")
|| strstr(bufp,"Lock")
|| strstr(bufp,"LOCK")
|| strstr(bufp,"wait")
/* these are blessed by RFC 2449 */
|| strstr(bufp,"[IN-USE]")||strstr(bufp,"[LOGIN-DELAY]"))
ok = PS_LOCKBUSY;
else if ((strstr(bufp,"Service")
|| strstr(bufp,"service"))
&& (strstr(bufp,"unavailable")))
ok = PS_SERVBUSY;
else
ok = PS_AUTHFAIL;
/*
* We always want to pass the user lock-busy messages, because
* they're red flags. Other stuff (like AUTH failures on non-
* RFC1734 servers) only if we're debugging.
*/
if (*bufp && (ok == PS_LOCKBUSY || outlevel >= O_MONITOR))
report(stderr, "%s\n", bufp);
}
else
ok = PS_PROTOCOL;
if (argbuf != NULL)
strcpy(argbuf,bufp);
}
return(ok);
}
static int pop3_getauth(int sock, struct query *ctl, char *greeting)
/* apply for connection authorization */
{
int ok;
char *start,*end;
char *msg;
#if OPIE_ENABLE
char *challenge;
#endif /* OPIE_ENABLE */
#if defined(GSSAPI)
flag has_gssapi = FALSE;
#endif /* defined(GSSAPI) */
#if defined(KERBEROS_V4) || defined(KERBEROS_V5)
flag has_kerberos = FALSE;
#endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
flag has_cram = FALSE;
#ifdef OPIE_ENABLE
flag has_otp = FALSE;
#endif /* OPIE_ENABLE */
#ifdef SDPS_ENABLE
/*
* This needs to catch both demon.co.uk and demon.net.
* If we see either, and we're in multidrop mode, try to use
* the SDPS *ENV extension.
*/
if (!(ctl->server.sdps) && MULTIDROP(ctl) && strstr(greeting, "demon."))
ctl->server.sdps = TRUE;
#endif /* SDPS_ENABLE */
switch (ctl->server.protocol) {
case P_POP3:
#ifdef RPA_ENABLE
/* CompuServe POP3 Servers as of 990730 want AUTH first for RPA */
if (strstr(ctl->remotename, "@compuserve.com"))
{
/* AUTH command should return a list of available mechanisms */
if (gen_transact(sock, "AUTH") == 0)
{
char buffer[10];
flag has_rpa = FALSE;
while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
{
if (DOTLINE(buffer))
break;
if (strncasecmp(buffer, "rpa", 3) == 0)
has_rpa = TRUE;
}
if (has_rpa && !POP3_auth_rpa(ctl->remotename,
ctl->password, sock))
return(PS_SUCCESS);
}
return(PS_AUTHFAIL);
}
#endif /* RPA_ENABLE */
/*
* CAPA command may return a list including available
* authentication mechanisms. if it doesn't, no harm done, we
* just fall back to a plain login. Note that this code
* latches the server's authentication type, so that in daemon mode
* the CAPA check only needs to be done once at start of run.
*
* APOP was introduced in RFC 1450, and CAPA not until
* RFC2449. So the < check is an easy way to prevent CAPA from
* being sent to the more primitive POP3 servers dating from
* RFC 1081 and RFC 1225, which seem more likely to choke on
* it. This certainly catches IMAP-2000's POP3 gateway.
*
* These authentication methods are blessed by RFC1734,
* describing the POP3 AUTHentication command.
*/
if (ctl->server.authenticate == A_ANY
&& strchr(greeting, '<')
&& gen_transact(sock, "CAPA") == 0)
{
char buffer[64];
/* determine what authentication methods we have available */
while ((ok = gen_recv(sock, buffer, sizeof(buffer))) == 0)
{
if (DOTLINE(buffer))
break;
#if defined(GSSAPI)
if (strstr(buffer, "GSSAPI"))
has_gssapi = TRUE;
#endif /* defined(GSSAPI) */
#if defined(KERBEROS_V4)
if (strstr(buffer, "KERBEROS_V4"))
has_kerberos = TRUE;
#endif /* defined(KERBEROS_V4) */
#ifdef OPIE_ENABLE
if (strstr(buffer, "X-OTP"))
has_otp = TRUE;
#endif /* OPIE_ENABLE */
if (strstr(buffer, "CRAM-MD5"))
has_cram = TRUE;
}
}
/*
* OK, we have an authentication type now.
*/
#if defined(KERBEROS_V4)
/*
* Servers doing KPOP have to go through a dummy login sequence
* rather than doing SASL.
*/
if (has_kerberos &&
#if INET6_ENABLE
ctl->server.service && (strcmp(ctl->server.service, KPOP_PORT)!=0)
#else /* INET6_ENABLE */
ctl->server.port != KPOP_PORT
#endif /* INET6_ENABLE */
&& (ctl->server.authenticate == A_KERBEROS_V4
|| ctl->server.authenticate == A_KERBEROS_V5
|| ctl->server.authenticate == A_ANY))
{
ok = do_rfc1731(sock, "AUTH", ctl->server.truename);
if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
break;
}
#endif /* defined(KERBEROS_V4) || defined(KERBEROS_V5) */
#if defined(GSSAPI)
if (has_gssapi &&
(ctl->server.authenticate == A_GSSAPI ||
ctl->server.authenticate == A_ANY))
{
ok = do_gssauth(sock,"AUTH",ctl->server.truename,ctl->remotename);
if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
break;
}
#endif /* defined(GSSAPI) */
#ifdef OPIE_ENABLE
if (has_otp &&
(ctl->server.authenticate == A_OTP ||
ctl->server.authenticate == A_ANY))
{
ok = do_otp(sock, "AUTH", ctl);
if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
break;
}
#endif /* OPIE_ENABLE */
if (has_cram &&
(ctl->server.authenticate == A_CRAM_MD5 ||
ctl->server.authenticate == A_ANY))
{
ok = do_cram_md5(sock, "AUTH", ctl);
if (ok == PS_SUCCESS || ctl->server.authenticate != A_ANY)
break;
}
/* ordinary validation, no one-time password or RPA */
gen_transact(sock, "USER %s", ctl->remotename);
strcpy(shroud, ctl->password);
ok = gen_transact(sock, "PASS %s", ctl->password);
shroud[0] = '\0';
break;
case P_APOP:
/* build MD5 digest from greeting timestamp + password */
/* find start of timestamp */
for (start = greeting; *start != 0 && *start != '<'; start++)
continue;
if (*start == 0) {
report(stderr,
_("Required APOP timestamp not found in greeting\n"));
return(PS_AUTHFAIL);
}
/* find end of timestamp */
for (end = start; *end != 0 && *end != '>'; end++)
continue;
if (*end == 0 || end == start + 1) {
report(stderr,
_("Timestamp syntax error in greeting\n"));
return(PS_AUTHFAIL);
}
else
*++end = '\0';
/* copy timestamp and password into digestion buffer */
xalloca(msg, char *, (end-start+1) + strlen(ctl->password) + 1);
strcpy(msg,start);
strcat(msg,ctl->password);
strcpy(ctl->digest, MD5Digest((unsigned char *)msg));
ok = gen_transact(sock, "APOP %s %s", ctl->remotename, ctl->digest);
break;
case P_RPOP:
if ((ok = gen_transact(sock,"USER %s", ctl->remotename)) == 0)
ok = gen_transact(sock, "RPOP %s", ctl->password);
break;
default:
report(stderr, _("Undefined protocol request in POP3_auth\n"));
ok = PS_ERROR;
}
if (ok != 0)
{
/* maybe we detected a lock-busy condition? */
if (ok == PS_LOCKBUSY)
report(stderr, _("lock busy! Is another session active?\n"));
return(ok);
}
/*
* Empirical experience shows some server/OS combinations
* may need a brief pause even after any lockfiles on the
* server are released, to give the server time to finish
* copying back very large mailfolders from the temp-file...
* this is only ever an issue with extremely large mailboxes.
*/
sleep(3); /* to be _really_ safe, probably need sleep(5)! */
/* we're peek-capable if use of TOP is enabled */
peek_capable = !(ctl->fetchall || ctl->keep);
/* we're approved */
return(PS_SUCCESS);
}
static int pop3_gettopid( int sock, int num , char *id)
{
int ok;
int got_it;
char buf [POPBUFSIZE+1];
sprintf( buf, "TOP %d 1", num );
if ((ok = gen_transact(sock, buf )) != 0)
return ok;
got_it = 0;
while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{
if (DOTLINE(buf))
break;
if ( ! got_it && ! strncasecmp("Message-Id:", buf, 11 )) {
got_it = 1;
/* prevent stack overflows */
buf[IDLEN+12] = 0;
sscanf( buf+12, "%s", id);
}
}
return 0;
}
static int pop3_slowuidl( int sock, struct query *ctl, int *countp, int *newp)
{
/* This approach tries to get the message headers from the
* remote hosts and compares the message-id to the already known
* ones:
* + if the first message containes a new id, all messages on
* the server will be new
* + if the first is known, try to estimate the last known message
* on the server and check. If this works you know the total number
* of messages to get.
* + Otherwise run a binary search to determine the last known message
*/
int ok, nolinear = 0;
int first_nr, list_len, try_id, try_nr, add_id;
int num;
char id [IDLEN+1];
if( (ok = pop3_gettopid( sock, 1, id )) != 0 )
return ok;
if( ( first_nr = str_nr_in_list(&ctl->oldsaved, id) ) == -1 ) {
/* the first message is unknown -> all messages are new */
*newp = *countp;
return 0;
}
/* check where we expect the latest known message */
list_len = count_list( &ctl->oldsaved );
try_id = list_len - first_nr; /* -1 + 1 */
if( try_id > 1 ) {
if( try_id <= *countp ) {
if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
return ok;
try_nr = str_nr_last_in_list(&ctl->oldsaved, id);
} else {
try_id = *countp+1;
try_nr = -1;
}
if( try_nr != list_len -1 ) {
/* some messages inbetween have been deleted... */
if( try_nr == -1 ) {
nolinear = 1;
for( add_id = 1<<30; add_id > try_id-1; add_id >>= 1 )
;
for( ; add_id; add_id >>= 1 ) {
if( try_nr == -1 ) {
if( try_id - add_id <= 1 ) {
continue;
}
try_id -= add_id;
} else
try_id += add_id;
if( (ok = pop3_gettopid( sock, try_id, id )) != 0 )
return ok;
try_nr = str_nr_in_list(&ctl->oldsaved, id);
}
if( try_nr == -1 ) {
try_id--;
}
} else {
report(stderr,
_("Messages inserted into list on server. Cannot handle this.\n"));
return -1;
}
}
}
/* the first try_id messages are known -> copy them to the newsaved list */
for( num = first_nr; num < list_len; num++ )
{
struct idlist *new = save_str(&ctl->newsaved,
str_from_nr_list(&ctl->oldsaved, num),
UID_UNSEEN);
new->val.status.num = num - first_nr + 1;
}
if( nolinear ) {
free_str_list(&ctl->oldsaved);
ctl->oldsaved = 0;
last = try_id;
}
*newp = *countp - try_id;
return 0;
}
static int pop3_getrange(int sock,
struct query *ctl,
const char *folder,
int *countp, int *newp, int *bytes)
/* get range of messages to be fetched */
{
int ok;
char buf [POPBUFSIZE+1];
/* Ensure that the new list is properly empty */
ctl->newsaved = (struct idlist *)NULL;
#ifdef MBOX
/* Alain Knaff suggests this, but it's not RFC standard */
if (folder)
if ((ok = gen_transact(sock, "MBOX %s", folder)))
return ok;
#endif /* MBOX */
/* get the total message count */
gen_send(sock, "STAT");
ok = pop3_ok(sock, buf);
if (ok == 0)
sscanf(buf,"%d %d", countp, bytes);
else
return(ok);
/*
* Newer, RFC-1725-conformant POP servers may not have the LAST command.
* We work as hard as possible to hide this ugliness, but it makes
* counting new messages intrinsically quadratic in the worst case.
*/
last = 0;
*newp = -1;
if (*countp > 0 && !ctl->fetchall)
{
char id [IDLEN+1];
if (!ctl->server.uidl) {
gen_send(sock, "LAST");
ok = pop3_ok(sock, buf);
} else
ok = 1;
if (ok == 0)
{
if (sscanf(buf, "%d", &last) == 0)
{
report(stderr, _("protocol error\n"));
return(PS_ERROR);
}
*newp = (*countp - last);
}
else
{
/* grab the mailbox's UID list */
if ((ok = gen_transact(sock, "UIDL")) != 0)
{
/* don't worry, yet! do it the slow way */
if((ok = pop3_slowuidl( sock, ctl, countp, newp))!=0)
{
report(stderr, _("protocol error while fetching UIDLs\n"));
return(PS_ERROR);
}
}
else
{
int num;
*newp = 0;
while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{
if (DOTLINE(buf))
break;
else if (sscanf(buf, "%d %s", &num, id) == 2)
{
struct idlist *new;
new = save_str(&ctl->newsaved, id, UID_UNSEEN);
new->val.status.num = num;
if (str_in_list(&ctl->oldsaved, id, FALSE)) {
new->val.status.mark = UID_SEEN;
str_set_mark(&ctl->oldsaved, id, UID_SEEN);
}
else
(*newp)++;
}
}
}
}
}
return(PS_SUCCESS);
}
static int pop3_getsizes(int sock, int count, int *sizes)
/* capture the sizes of all messages */
{
int ok;
if ((ok = gen_transact(sock, "LIST")) != 0)
return(ok);
else
{
char buf [POPBUFSIZE+1];
while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{
int num, size;
if (DOTLINE(buf))
break;
else if (sscanf(buf, "%d %d", &num, &size) == 2)
sizes[num - 1] = size;
}
return(ok);
}
}
static int pop3_is_old(int sock, struct query *ctl, int num)
/* is the given message old? */
{
if (!ctl->oldsaved)
return (num <= last);
else
return (str_in_list(&ctl->oldsaved,
str_find(&ctl->newsaved, num), FALSE));
}
#ifdef UNUSED
/*
* We could use this to fetch headers only as we do for IMAP. The trouble
* is that there's no way to fetch the body only. So the following RETR
* would have to re-fetch the header. Enough messages have longer headers
* than bodies to make this a net loss.
*/
static int pop_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
/* request headers of nth message */
{
int ok;
char buf[POPBUFSIZE+1];
gen_send(sock, "TOP %d 0", number);
if ((ok = pop3_ok(sock, buf)) != 0)
return(ok);
*lenp = -1; /* we got sizes from the LIST response */
return(PS_SUCCESS);
}
#endif /* UNUSED */
static int pop3_fetch(int sock, struct query *ctl, int number, int *lenp)
/* request nth message */
{
int ok;
char buf[POPBUFSIZE+1];
#ifdef SDPS_ENABLE
/*
* See http://www.demon.net/services/mail/sdps-tech.html
* for a description of what we're parsing here.
*/
if (ctl->server.sdps)
{
int linecount = 0;
sdps_envfrom = (char *)NULL;
sdps_envto = (char *)NULL;
gen_send(sock, "*ENV %d", number);
do {
if (gen_recv(sock, buf, sizeof(buf)))
{
break;
}
linecount++;
switch (linecount) {
case 4:
/* No need to wrap envelope from address */
sdps_envfrom = xmalloc(strlen(buf)+1);
strcpy(sdps_envfrom,buf);
break;
case 5:
/* Wrap address with To: <> so nxtaddr() likes it */
sdps_envto = xmalloc(strlen(buf)+7);
sprintf(sdps_envto,"To: <%s>",buf);
break;
}
} while
(!(buf[0] == '.' && (buf[1] == '\r' || buf[1] == '\n' || buf[1] == '\0')));
}
#endif /* SDPS_ENABLE */
/*
* Though the POP RFCs don't document this fact, on almost every
* POP3 server I know of messages are marked "seen" only at the
* time the OK response to a RETR is issued.
*
* This means we can use TOP to 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. (Exception: in early 1999 SpryNet's POP3 servers were
* reported to mark messages seen on a TOP fetch.)
*
* However...*don't* do this if we're using keep to suppress deletion!
* In that case, marking the seen flag is the only way to prevent the
* message from being re-fetched on subsequent runs.
*
* Also use RETR if fetchall is on. This gives us a workaround
* for servers like usa.net's that bungle TOP. It's pretty
* harmless because fetchall guarantees that any message dropped
* by an interrupted RETR will be picked up on the next poll of the
* site.
*
* We take advantage here of the fact that, according to all the
* POP RFCs, "if the number of lines requested by the POP3 client
* is greater than than the number of lines in the body, then the
* POP3 server sends the entire message.").
*
* The line count passed (99999999) is the maximum value CompuServe will
* accept; it's much lower than the natural value 2147483646 (the maximum
* twos-complement signed 32-bit integer minus 1) */
if (ctl->keep || ctl->fetchall)
gen_send(sock, "RETR %d", number);
else
gen_send(sock, "TOP %d 99999999", number);
if ((ok = pop3_ok(sock, buf)) != 0)
return(ok);
*lenp = -1; /* we got sizes from the LIST response */
return(PS_SUCCESS);
}
static int pop3_delete(int sock, struct query *ctl, int number)
/* delete a given message */
{
/* actually, mark for deletion -- doesn't happen until QUIT time */
return(gen_transact(sock, "DELE %d", number));
}
static int pop3_logout(int sock, struct query *ctl)
/* send logout command */
{
int ok;
ok = gen_transact(sock, "QUIT");
if (!ok)
expunge_uids(ctl);
if (ctl->lastid)
{
free(ctl->lastid);
ctl->lastid = NULL;
}
return(ok);
}
const static struct method pop3 =
{
"POP3", /* Post Office Protocol v3 */
#if INET6_ENABLE
"pop3", /* standard POP3 port */
"pop3s", /* ssl POP3 port */
#else /* INET6_ENABLE */
110, /* standard POP3 port */
995, /* ssl POP3 port */
#endif /* INET6_ENABLE */
FALSE, /* this is not a tagged protocol */
TRUE, /* this uses a message delimiter */
pop3_ok, /* parse command response */
pop3_getauth, /* get authorization */
pop3_getrange, /* query range of messages */
pop3_getsizes, /* we can get a list of sizes */
pop3_is_old, /* how do we tell a message is old? */
pop3_fetch, /* request given message */
NULL, /* no way to fetch body alone */
NULL, /* no message trailer */
pop3_delete, /* how to delete a message */
pop3_logout, /* log out, we're done */
FALSE, /* no, we can't re-poll */
};
int doPOP3 (struct query *ctl)
/* retrieve messages using POP3 */
{
#ifndef MBOX
if (ctl->mailboxes->id) {
fprintf(stderr,_("Option --remote is not supported with POP3\n"));
return(PS_SYNTAX);
}
#endif /* MBOX */
peek_capable = !ctl->fetchall;
return(do_protocol(ctl, &pop3));
}
#endif /* POP3_ENABLE */
/* pop3.c ends here */