/* Mixmaster version 2.9 -- (C) 1999 - 2003 Anonymizer Inc. and others.
Mixmaster may be redistributed and modified under certain conditions.
This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
ANY KIND, either express or implied. See the file COPYRIGHT for
details.
Process remailer messages
$Id: rem.c 665 2003-11-09 01:47:32Z rabbi $ */
#include "mix3.h"
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef POSIX
#include <unistd.h>
#else /* end of POSIX */
#include <io.h>
#endif /* else if not POSIX */
#ifndef _MSC_VER
#include <dirent.h>
#endif /* not _MSC_VER */
#include <assert.h>
int blockrequest(BUFFER *message);
#define REQUESTHELP 100
#define REQUESTSTATS 101
#define REQUESTKEY 200
#define REQUESTCONF 201
#define REQUESTOPKEY 202
#define BLOCKREQUEST 666
#define DISABLED 99
#define CPUNKMSG 1
#define MIXMSG 2
int mix_decrypt(BUFFER *message)
{
int type = 0;
BUFFER *field, *content;
BUFFER *to, *subject, *replyto, *reply;
FILE *f;
BUFFER *block;
int err = 0;
int quoted_printable = 0; /* is this message quoted printable encoded */
mix_init(NULL);
field = buf_new();
content = buf_new();
to = buf_new();
replyto = buf_new();
reply = buf_new();
block = buf_new();
subject = buf_new();
buf_sets(subject, "Subject: Re: your mail");
buf_rewind(message);
f = mix_openfile(SOURCEBLOCK, "r");
if (f != NULL) {
buf_read(block, f);
fclose(f);
}
for (;;) {
err = buf_getheader(message, field, content);
if (err == 1) {
/* "::" marks for additional header lines */
while (buf_lookahead(message, field) == 1)
buf_getheader(message, field, content);
if (isline(field, HDRMARK))
continue;
else
goto hdrend;
}
if (err == -1)
goto hdrend;
if ((bufieq(field, "from") || bufieq(field, "sender") || bufieq(field,"received")) &&
doblock(content, block, 1) != 0)
goto end;
if (bufieq(field, "to"))
buf_cat(to, content);
else if (bufieq(field, "from") && replyto->length == 0)
/* reply to From address if no Reply-To header present */
buf_set(replyto, content);
else if (bufieq(field, "reply-to"))
buf_set(replyto, content);
else if (MIX && bufieq(field, "remailer-type") &&
bufileft(content, "mixmaster"))
type = MIXMSG;
else if (bufieq(field, "subject")) {
if (bufieq(content, "help") || bufieq(content, "remailer-help"))
type = REQUESTHELP;
else if (bufieq(content, "remailer-stats"))
type = REQUESTSTATS;
else if (bufieq(content, "remailer-key"))
type = REQUESTKEY;
else if (bufieq(content, "remailer-adminkey"))
type = REQUESTOPKEY;
else if (bufieq(content, "remailer-conf"))
type = REQUESTCONF;
else if (bufileft(content, "destination-block"))
type = BLOCKREQUEST;
else {
buf_sets(subject, "Subject: ");
if (!bufileft(content, "re:"))
buf_appends(subject, "Re: ");
buf_cat(subject, content);
}
} else if (bufieq(field, "test-to") || bufieq(field, "encrypted") ||
bufieq(field, "anon-to") ||
bufieq(field, "request-remailing-to") ||
bufieq(field, "remail-to") || bufieq(field, "anon-post-to") ||
bufieq(field, "post-to") || bufieq(field, "anon-send-to") ||
bufieq(field, "send-to") || bufieq(field, "remix-to") ||
bufieq(field, "encrypt-to"))
type = CPUNKMSG;
else if (bufieq(field, "content-transfer-encoding")
&& bufieq(content, "quoted-printable")) {
quoted_printable = 1;
}
}
hdrend:
if (quoted_printable)
qp_decode_message(message);
if (type > 0 && REMAIL == 0)
type = DISABLED;
switch (type) {
case REQUESTHELP:
if (sendinfofile(HELPFILE, NULL, replyto, NULL) == -1)
errlog(WARNING, "No help file available.\n");
break;
case REQUESTKEY:
err = key(reply);
if (err == 0)
err = sendmail(reply, REMAILERNAME, replyto);
break;
case REQUESTOPKEY:
err = adminkey(reply);
if (err == 0)
err = sendmail(reply, REMAILERNAME, replyto);
break;
case REQUESTSTATS:
err = stats(reply);
if (err == 0)
err = sendmail(reply, REMAILERNAME, replyto);
break;
case REQUESTCONF:
err = conf(reply);
if (err == 0)
err = sendmail(reply, REMAILERNAME, replyto);
break;
case CPUNKMSG:
err = t1_decrypt(message);
if (err != 0) {
errlog(LOG, "Invalid type 1 message from %b\n", replyto);
sendinfofile(USAGEFILE, USAGELOG, replyto, NULL);
logmail(err == -2 ? MAILUSAGE : MAILERROR, message);
}
break;
case MIXMSG:
err = t2_decrypt(message);
if (err == -1) {
errlog(LOG, "Invalid type 2 message from %b\n", replyto);
sendinfofile(USAGEFILE, USAGELOG, replyto, NULL);
logmail(MAILERROR, message);
}
break;
case BLOCKREQUEST:
blockrequest(message);
logmail(MAILBLOCK, message);
break;
case DISABLED:
errlog(ERRORMSG, "Remailer is disabled.\n");
buf_sets(reply, "Subject: remailer error\n\nThe remailer is disabled.\n");
sendmail(reply, REMAILERNAME, replyto);
logmail(MAILERROR, message);
break;
default:
if (strifind
(replyto->data, "mailer-daemon")) {
errlog(LOG, "Bounce mail from %b\n", replyto);
logmail(MAILBOUNCE, message);
} else if (bufifind(to, REMAILERADDR) && blockrequest(message))
logmail(MAILBLOCK, message);
else if (!AUTOREPLY)
logmail(MAILBOX, message);
else if (bufifind(to, REMAILERADDR)) {
errlog(LOG, "Non-remailer message from %b\n", replyto);
sendinfofile(USAGEFILE, USAGELOG, replyto, NULL);
logmail(MAILUSAGE, message);
} else if (bufifind(to, COMPLAINTS)) {
errlog(WARNING, "Abuse complaint from %b\n", replyto);
sendinfofile(ABUSEFILE, NULL, replyto, subject);
logmail(MAILABUSE, message);
} else if (ANONADDR[0] && bufifind(to, ANONADDR)) {
errlog(LOG, "Reply to anonymous message from %b\n", replyto);
sendinfofile(REPLYFILE, NULL, replyto, subject);
logmail(MAILANON, message);
} else {
errlog(DEBUGINFO, "Mail from %b\n", replyto);
logmail(MAILBOX, message);
}
err = 1;
}
end:
buf_free(field);
buf_free(content);
buf_free(to);
buf_free(replyto);
buf_free(reply);
buf_free(block);
buf_free(subject);
return (err);
}
int t2_decrypt(BUFFER *in)
{
int err = 0;
BUFFER *msg;
msg = buf_new();
do {
err = mix_dearmor(in, msg);
if (err != -1) {
if (v3_magic(msg->data))
err = mix3_decrypt(msg);
else
err = mix2_decrypt(msg);
}
}
while (in->ptr + 1000 < in->length); /* accept several packets in one message */
buf_free(msg);
return (err);
}
int mix_pool(BUFFER *msg, int type, long latent)
{
char path[PATHMAX], pathtmp[PATHMAX];
FILE *f;
int err = -1;
f = pool_new(latent > 0 ? "lat" : "msg", pathtmp, path);
if (f != NULL) {
if (latent > 0)
fprintf(f, "%d %ld\n", type, latent + time(NULL));
else
fprintf(f, "%d 0\n", type);
err = buf_write_sync(msg, f);
}
if (err == 0) {
rename(pathtmp, path);
errlog(DEBUGINFO, "Added message to pool.\n");
}
return (err);
}
int pool_packetfile(char *fname, BUFFER *mid, int packetnum)
/* create a filename */
{
#ifdef SHORTNAMES
sprintf(fname, "%s%cp%02x%02x%02x%01x.%02x", POOLDIR, DIRSEP,
mid->data[0], mid->data[1], mid->data[2], mid->data[3] & 15,
packetnum);
#else /* end of SHORTNAMES */
sprintf(fname, "%s%cp%02x%02x%02x%02x%02x%02x%01x", POOLDIR, DIRSEP,
packetnum, mid->data[0], mid->data[1], mid->data[2], mid->data[3],
mid->data[4], mid->data[5] & 15);
#endif /* else if not SHORTNAMES */
return (0);
}
void pool_packetexp(void)
{
char *path;
DIR *d;
struct dirent *e;
struct stat sb;
d = opendir(POOLDIR);
errlog(DEBUGINFO, "Checking for old parts.\n");
if (d != NULL)
for (;;) {
e = readdir(d);
if (e == NULL)
break;
if (e->d_name[0] == 'p' || e->d_name[0] == 'e' || e->d_name[0] == 't') {
path=malloc(strlen(POOLDIR)+strlen(e->d_name)+strlen(DIRSEPSTR)+1);
if (path) {
strcpy(path, POOLDIR);
strcat(path, DIRSEPSTR);
strcat(path, e->d_name);
if (stat(path, &sb) == 0 && time(NULL) - sb.st_mtime > PACKETEXP) {
if (e->d_name[0] == 'p') {
errlog(NOTICE, "Expiring incomplete partial message %s.\n",
e->d_name);
}
else if (e->d_name[0] == 'e') {
errlog(NOTICE, "Expiring old error message %s.\n",
e->d_name);
}
else if (e->d_name[0] == 't') {
errlog(NOTICE, "Expiring moldy temporary message %s.\n",
e->d_name);
}
unlink(path);
}
free(path);
}
}
}
closedir(d);
}
void logmail(char *mailbox, BUFFER *message)
{
time_t t;
struct tm *tc;
char line[LINELEN];
/* mailbox is "|program", "user@host", "stdout" or "filename" */
buf_rewind(message);
if (mailbox[0] == '\0') /* default action */
mailbox = MAILBOX;
if (strieq(mailbox, "stdout"))
buf_write(message, stdout);
else if (mailbox[0] == '|') {
FILE *p;
errlog(DEBUGINFO, "Piping message to %s.\n", mailbox + 1);
p = openpipe(mailbox + 1);
if (p != NULL) {
buf_write(message, p);
closepipe(p);
}
} else if (strchr(mailbox, '@')) {
BUFFER *field, *content;
field = buf_new();
content = buf_new();
while (buf_getheader(message, field, content) == 0)
if (bufieq(field, "x-loop") && bufifind(content, REMAILERADDR)) {
errlog(WARNING, "Loop detected! Message not sent to %s.\n", mailbox);
goto isloop;
}
buf_sets(content, mailbox);
sendmail_loop(message, NULL, content);
isloop:
buf_free(field);
buf_free(content);
} else {
FILE *mbox;
mbox = mix_openfile(mailbox, "a");
if (mbox == NULL) {
errlog(ERRORMSG, "Can't write to mail folder %s\n", mailbox);
return;
}
lock(mbox);
if (!bufileft(message, "From ")) {
t = time(NULL);
tc = localtime(&t);
strftime(line, LINELEN, "From Mixmaster %a %b %d %H:%M:%S %Y\n", tc);
fprintf(mbox, line);
}
buf_write(message, mbox);
fprintf(mbox, "\n\n");
unlock(mbox);
fclose(mbox);
}
}
int blockrequest(BUFFER *message)
{
int request = 0, num, i;
BUFFER *from, *line, *field, *content, *addr, *remailer_addr, *copy_addr;
REMAILER remailer[MAXREM];
FILE *f;
char *destblklst = (char *)malloc( strlen(DESTBLOCK)+1 );
char *destblk;
from = buf_new();
line = buf_new();
field = buf_new();
content = buf_new();
addr = buf_new();
remailer_addr = buf_new();
copy_addr = buf_new();
if (destblklst == NULL) {
errlog(ERRORMSG, "Can't malloc %n bytes for destblklst.\n", strlen(DESTBLOCK)+1);
goto end;
};
buf_rewind(message);
while (buf_getheader(message, field, content) == 0)
if (bufieq(field, "from"))
buf_set(from, content);
else if (bufieq(field, "subject"))
buf_cat(message, content);
/* Append the subject to the message body so destination block requests
in the subject line work too (we process the body a few lines down) */
while (buf_getline(message, line) != -1)
if (bufifind(line, "destination-block")) {
buf_clear(addr);
request = 1;
{
int c = 0;
while (!strileft(line->data + line->ptr, "block"))
line->ptr++;
while (c != ' ' && c != -1)
c = tolower(buf_getc(line));
while (c == ' ')
c = buf_getc(line);
if (c != -1)
do {
buf_appendc(addr, c);
c = buf_getc(line);
} while (c > ' ');
}
if (addr->length == 0) {
rfc822_addr (from, addr);
buf_chop(addr);
}
/* Check whether somebody wants us to block ourselves */
buf_set(copy_addr, addr);
buf_sets(remailer_addr, REMAILERADDR);
if (doblock(remailer_addr, copy_addr, 1)) {
errlog(LOG, "Ignoring blocking request for %b from %b.\n", addr, from);
request = 2;
goto end;
}
/* Check if some evil person tries to block a known type II remailer */
num = mix2_rlist(remailer);
for (i = 0; i < num; i++) {
buf_sets(remailer_addr, remailer[i].addr);
if (doblock(remailer_addr, copy_addr, 1)) {
errlog(LOG, "Ignoring blocking request for %b from %b.\n", addr, from);
request = 2;
goto end;
}
}
/* Check if some evil person tries to block a known type I remailer */
num = t1_rlist(remailer);
for (i = 0; i < num; i++) {
buf_sets(remailer_addr, remailer[i].addr);
if (doblock(remailer_addr, copy_addr, 1)) {
errlog(LOG, "Ignoring blocking request for %b from %b.\n", addr, from);
request = 2;
goto end;
}
}
if (buf_ieq(addr, from))
errlog(NOTICE, "Blocking request for %b\n", addr);
else
errlog(NOTICE, "Blocking request for %b from %b\n", addr, from);
if (AUTOBLOCK) {
buf_clear(line);
rfc822_addr(addr, line);
if (line->length == 0) {
errlog(LOG, "Nothing to block after rfc822_addr().\n");
} else
if (bufleft(line, "/")) {
errlog(LOG, "Ignoring blocking request: %b is a regex.\n", addr);
} else {
if (strchr(line->data, '@') && strchr(strchr(line->data, '@'), '.')) {
strcpy( destblklst, DESTBLOCK );
destblk = strtok( destblklst, " " );
f = mix_openfile( destblk, "a" );
if (f != NULL) {
lock(f);
buf_chop(line);
sendinfofile(BLOCKFILE, NULL, line, NULL);
if (line->length) {
fprintf(f, "%s\n", line->data);
} else
errlog(NOTICE, "%b already blocked.\n", addr);
unlock(f);
fclose(f);
} else
errlog(ERRORMSG, "Can't write to %s.\n", DESTBLOCK);
} else
errlog(WARNING, "Invalid address not added to %s: %b\n", DESTBLOCK,
addr);
}
}
}
end:
free( destblklst );
buf_free(from);
buf_free(line);
buf_free(field);
buf_free(content);
buf_free(addr);
buf_free(remailer_addr);
buf_free(copy_addr);
return (request);
}
int idexp(void)
{
FILE *f;
BUFFER *b;
long now, then;
LOCK *i;
idlog_t idbuf;
long fpi = sizeof(idlog_t), fpo = sizeof(idlog_t);
if (IDEXP == 0)
return (0);
b = buf_new();
f = mix_openfile(IDLOG, "rb+");
if (f == NULL)
return (-1);
i = lockfile(IDLOG);
now = time(NULL);
if (fread(&idbuf, 1, sizeof(idlog_t), f) != sizeof(idlog_t)) { /* replace first line */
fclose(f);
unlockfile(i);
return (-1);
}
then = idbuf.time;
memset(idbuf.id,0,sizeof(idbuf.id));
idbuf.time = now - IDEXP;
fseek(f,0,SEEK_SET);
fwrite(&idbuf,1,sizeof(idlog_t),f);
fseek(f,fpi,SEEK_SET); /* this fseek does nothing, but MSVC CRT happilly reads past EOF (!!!) if we do not fseek here :-/ */
while (fread(&idbuf, 1, sizeof(idlog_t), f) == sizeof(idlog_t)) {
fpi+=sizeof(idlog_t);
then = idbuf.time;
if (now - then < IDEXP &&
now - then > - SECONDSPERDAY * 180 )
/* also expire packets that are dated more than half a year in the future.
* That way we get rid of invalid packets introduced by the switch to a
* binary id.log. */
{
fseek(f,fpo,SEEK_SET);
fwrite(&idbuf,1,sizeof(idlog_t),f);
fpo += sizeof(idlog_t);
fseek(f,fpi,SEEK_SET);
}
}
#ifdef _MSC_VER
chsize(fileno(f),fpo);
#else /* end of _MSC_VER */
ftruncate(fileno(f),fpo);
#endif /* else if not _MSC_VER */
fclose(f);
unlockfile(i);
buf_free(b);
return (0);
}
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