Commit ce174152 authored by Devon Kearns's avatar Devon Kearns

Imported Upstream version 0.5.2

parents
Olivier Dembour <olivier.dembour@hsc.fr>
Contributors :
Nicolas Collignon <collignon@hsc.fr>
This diff is collapsed.
Version 0.5.2
Removal of left OpenSSL includes
Version 0.5.1
Remove OpenSSL library due to GPL conflicts
- Add specific PolarSSL hmac functions in dns2tcp
- No more external library needed
Kill child when authentication fails
Remove useless '=' padding
Version 0.5
Typo fixed in config file :
resource is know correctly written (with one 's')
Client now compiles and works under Windows (by Nicolas Collignon)
find the first DNS if server not specified
add --disable-{client,server} option in Makefile
Request type are now independant (TXT, KEY)
Add a client authentication (identification)
Fix bind problem and typo (Thanks Taylor R Campbell)
Server now put the AA flag in reply (Thanks Taylor R Campbell)
Client can execute command (for reverse connection)
dns2tcpc can be used as a proxy (like ProxyCommand for SSH)
pid file can be defined in the config file (patch from Michael Scherer)
Version 0.4.3
Fix buffer overflow and error in dns_decode (John Lampe)
Fix drop privileges problems (Solar Designer)
Add limit to prevent fork() (Idea from Solar Designer)
Version 0.4.2
Suppressed
Version 0.4.1
Fix buffer overflow in dns_decode
Fix bind Problem (thanks Taylor R Campbell)
Fix compilation problem in FreeBSD
Version 0.4
Typo fixed in README, manpages
64 bits architectures now working
Fix bind on 0.0.0.0 in server (Thanks Charlie Von Metzradt)
client more reliable
Version 0.3
public release
Basic Installation
==================
These are generic installation instructions.
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(useful mainly for debugging `configure').
If you need to do unusual things to compile the package, please try
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Compilers and Options
=====================
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CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
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env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
Compiling For Multiple Architectures
====================================
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==================
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=================
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package recognizes.
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find the X include and library files automatically, but if it doesn't,
you can use the `configure' options `--x-includes=DIR' and
`--x-libraries=DIR' to specify their locations.
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==========================
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CPU-COMPANY-SYSTEM
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use the `--target=TYPE' option to select the type of system they will
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system on which you are compiling the package.
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================
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you can create a site shell script called `config.site' that gives
default values for variables like `CC', `cache_file', and `prefix'.
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`CONFIG_SITE' environment variable to the location of the site script.
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==================
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`--help'
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messages will still be shown).
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# $Id: Makefile.am,v 1.3.4.1 2010/05/18 15:35:47 dembour Exp $
SUBDIRS = $(DIRECTORIES) man
DIST_SUBDIRS = $(DIRECTORIES) man
EXTRA_DIST = common
dist-hook:
rm -rf `find $(distdir)/ -name CVS`
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---------- [ Note ] ----------
Dns2tcp is a tool for relaying TCP connections over DNS. There is only
a simple identification mecanism but no encryption : DNS encapsulation
must be considered as an unsecure and anonymous transport
layer. Resources should be public external services like ssh,
ssltunnel ...
----------[ Examples ]----------
Client:
------
View list of available connection.
$ dns2tcpc -z dns2tcp.hsc.fr -k <my-key> <dns_server>
Available connection(s) :
ssh-gw
ssh6-home
ssl-tunnel
$
Line based connection to a remote ssl-tunnel host :
$ dns2tcpc -r ssl-tunnel -l 4430 -k <my-key> -z dns2tcp._hsc.fr <dns_server>
listening on port 4430
...
File configuration :
$ cat > ~/.dns2tcprc << EOF
domain = dns2tcp.hsc.fr
resource = ssl-tunnel
local_port = 4430
debug_level = 1
key = whateveryouwant
server = the_dns_server # or scan /etc/resolv.conf
EOF
$ dns2tcpc
Server :
-------
File configuration :
$ cat > ~/.dns2tcpdrc << EOF
listen = x.x.x.x
port = 53
user = nobody
key = whateveryouwant
chroot = /var/empty/dns2tcp/
domain = dns2tcp.hsc.fr
resources = ssh:127.0.0.1:22 , smtp:127.0.0.1:25,
pop3:10.0.0.1:110, ssh2:[fe80::1664]:22
EOF
$ ./dns2tcpd -F -d 1
----------[ Known Bugs ]----------
DNS desynchronisation
dns2tcpd server not supported on Windows
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bin_PROGRAMS = dns2tcpc
INCLUDES = -I./includes/ -I../common/includes
CLEANFILES= *~ *.~ \#*
EXTRA_DIST = includes dns2tcprc
dns2tcpc_SOURCES = \
../common/hmac_sha1.c \
select.c \
../common/crc16.c \
rr.c \
../common/mycrypto.c \
command.c \
session.c \
../common/config.c \
queue.c \
client.c \
../common/list.c \
../common/myrand.c \
auth.c \
../common/dns.c \
../common/mystrnlen.c \
requests.c \
../common/memdump.c \
../common/base64.c \
socket.c \
options.c \
main.c
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/*
** Copyright (C) 2006 Olivier DEMBOUR
** $Id: auth.c,v 1.19.4.3 2010/01/06 12:50:40 dembour Exp $
**
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with This program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdio.h>
#include "client.h"
#include "dns.h"
#include "myerror.h"
#include "list.h"
#include "requests.h"
#include "socket.h"
#include "base64.h"
#include "myrand.h"
#include "session.h"
#include "myerror.h"
#include "debug.h"
#include "rr.h"
/**
* @brief ask and list remote resource available
* @param[in] conf configuration
* @retval 0 on success
* @retval -1 on error
**/
int list_resources(t_conf *conf)
{
char domain[MAX_DNS_LEN + 1];
char buffer[MAX_DNS_LEN + 1];
int len;
uint16_t id, session_id;
t_request request;
uint32_t count = 0;
uint8_t compress;
if (!((session_id = create_session(conf))))
return (-1);
if (create_simple_req(conf, &request, RESOURCE, (char *)&domain, session_id))
return (-1);
DPRINTF(1, "Requesting resource\n");
if ((id = send_query(conf, &request)) == 0)
return (-1);
if (!(request.len = get_simple_reply(conf, (char *)&request.req_data, id)))
return (-1);
printf("Available connection(s) : \n");
while ((len = request.request_functions->rr_decode_next_reply(&request, (char *)&buffer, MAX_DNS_LEN , count++)))
{
buffer[len] = 0;
printf("\t%s\n", &buffer[PACKET_LEN]);
}
compress = query_is_compressed((char *)&(request.req_data), request.len);
printf("\nNote : Compression %s available !\n", compress ? "SEEMS" : "NOT");
return (0);
}
/**
* @brief connect to a specific ressource
* @param[in] conf configuration
* @param[in] session_id session identifier
* @retval 0 on success
* @retval 1 on error
**/
uint16_t connect_resource(t_conf *conf, uint16_t session_id)
{
char domain[MAX_DNS_LEN + 1];
char *resource;
char buffer[MAX_DNS_LEN + 1];
int len;
t_request request;
t_packet *packet;
if (create_simple_req(conf, &request, CONNECT, (char *)&domain, session_id))
return(-1);
resource = &request.req_data[PACKET_LEN];
DPRINTF(1, "Connect to resource \"%s\"\n", conf->resource);
strncpy(resource, conf->resource, sizeof(request.req_data) - PACKET_LEN - 1);
request.len = PACKET_LEN + strlen(conf->resource);
if ((len = transceive_query(conf, &request, (char *)&buffer, sizeof(buffer)-1 )) == -1)
return (1);
buffer[len] = 0;
packet = (t_packet *)&buffer;
if (packet->type != OK)
fprintf(stderr, "Error : %s\n", (char *) (packet+1));
return (packet->type != OK);
}
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/*
** Copyright (C) 2006 Olivier DEMBOUR
** $Id: command.c,v 1.4.4.4 2010/06/01 15:25:29 collignon Exp $
**
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with This program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _WIN32
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#else
#include "mywin32.h"
#endif
#include <signal.h>
#include <stdlib.h>
#include <errno.h>
#include "myerror.h"
#include "list.h"
#include "client.h"
#include "debug.h"
#define IS_SEPARATOR(c) ((c == ' ') || (c == '\t') || (c == '\n'))
#define MAX_ARG_SIZE 64
#ifndef _WIN32
/**
* @brief find numbers of arguments
* @param[in] cmdline command to execute
* @retval numbers of arguments
**/
int count_arg(char *cmdline)
{
int i = 0;
while (*cmdline)
if (IS_SEPARATOR(*cmdline++))
i++;
return (i);
}
/**
* @brief convert command line into argv
* @param[in] line command line
* @param[in] argv table
**/
void line_to_argv(char *line, char **argv)
{
int i = 0;
if (!IS_SEPARATOR(*line))
argv[i++] = line;
while (*line)
{
while ((*line) && (!IS_SEPARATOR(*line)))
line++;
while ((*line) && (IS_SEPARATOR(*line)))
*line++ = 0;
argv[i++] = *line? line: 0;
}
}
/**
* @brief create a process, add it into client list
* @param[in] conf configuration
* @retval 0 on success
* @retval -1 on error
**/
int create_process(t_conf *conf)
{
int from_child[2];
int to_child[2];
int status;
pid_t pid;
if ((pipe(from_child) == -1) || (pipe(to_child) == -1))
{
perror("pipe");
exit(-1);
}
pid = fork();
if (!pid)
{
char *argv[MAX_ARG_SIZE];
line_to_argv(conf->cmdline, argv);
if (count_arg(conf->cmdline) > MAX_ARG_SIZE)
{
fprintf(stderr, "Arg size > MAX_ARG_SIZE\n");
exit (-1);
}
if (dup2(to_child[0], STDIN_FILENO) == -1)
return (-1);
if (dup2(from_child[1], STDOUT_FILENO) == -1)
return (-1);
if (dup2(from_child[1], STDERR_FILENO) == -1)
return (-1);
close(from_child[0]);
close(to_child[0]);
execv(argv[0],argv);
fprintf(stderr, "execv error (%d) for '%s'\n", errno, conf->cmdline);
exit(1);
}
DPRINTF(1, "Executing %s (Pid %d)\n", conf->cmdline, (int)pid);
close(from_child[1]);
close(to_child[0]);
if (add_client(conf, from_child[0], to_child[1] , pid))
{
/* BUGFIX: child process not killed if auth has failed (with -e) */
kill(pid, SIGKILL);
waitpid(-1, &status, WNOHANG);
close(from_child[0]); close(to_child[1]);
return (-1);
}
return (0);
}
#else
/*
* Windows pipe handling simply *SUX*
* It doesn't seem possible to perform asynchronous I/O on anonymous pipes.
* ReadFile() will block if there is no pending data. We don't want to use
* any additional thread.
* So we have to use named pipe... nasty ugly trick ...
*/
static int create_pipe(HANDLE *rfd, HANDLE *wfd, int async_read, SECURITY_ATTRIBUTES *attr)
{
char name[128];
sprintf(name, "\\\\.\\pipe\\win-sux-no-async-anon-pipe-%lu-%i",
GetCurrentProcessId(), rand());
DPRINTF(2, "using pipe %s\n", name);
*rfd = CreateNamedPipe(name,
PIPE_ACCESS_INBOUND|(async_read ? FILE_FLAG_OVERLAPPED : 0),
PIPE_TYPE_BYTE|PIPE_WAIT, 2, 4096, 4096,
5000 /*msec*/, attr);
if (*rfd == INVALID_HANDLE_VALUE)
{
MYERROR("error: failed to create pipe\n");
return -1;
}
*wfd = CreateFile(name, GENERIC_WRITE, 0, attr,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (*wfd == INVALID_HANDLE_VALUE) {
MYERROR("error: failed to create pipe\n");
CloseHandle(*rfd);
return -1;
}
return 0;
}
int create_process(t_conf *conf)
{
BOOL res;
HANDLE stdin_child, stdin_parent, stdout_parent, stdout_child, stderr_child;
DWORD pid;
SECURITY_ATTRIBUTES sattr;
PROCESS_INFORMATION pi;
STARTUPINFO si;
ZeroMemory(&sattr, sizeof(sattr));
ZeroMemory(&pi, sizeof(pi));
ZeroMemory(&si, sizeof(si));
sattr.nLength = sizeof(sattr);
sattr.bInheritHandle = TRUE;
// stdin pipe
if (create_pipe(&stdin_child, &stdin_parent, 0, &sattr))
return -1;
// stdout pipe
if (create_pipe(&stdout_parent, &stdout_child, 1, &sattr))
{
CloseHandle(stdin_child);
CloseHandle(stdin_parent);
return -1;
}
// stderr pipe
if (!DuplicateHandle(GetCurrentProcess(), stdout_child,
GetCurrentProcess(), &stderr_child,
0, TRUE, DUPLICATE_SAME_ACCESS))
{
MYERROR("error: failed to duplicate pipe handle\n");
CloseHandle(stdin_child);
CloseHandle(stdin_parent);
CloseHandle(stdout_child);
CloseHandle(stdout_parent);
return -1;
}
SetHandleInformation(stdin_parent, HANDLE_FLAG_INHERIT, 0);
SetHandleInformation(stdout_parent, HANDLE_FLAG_INHERIT, 0);
si.cb = sizeof(si);
si.dwFlags = STARTF_USESTDHANDLES;
si.hStdInput = stdin_child;
si.hStdOutput = stdout_child;
si.hStdError = stderr_child;
//FIXME print error
res = CreateProcess(NULL, conf->cmdline, NULL, NULL, TRUE, 0,
NULL, NULL, &si, &pi);
CloseHandle(stdin_child);
CloseHandle(stdout_child);
CloseHandle(stderr_child);
if (!res)
{
MYERROR("error: failed to create process (%lu)\n", GetLastError());
CloseHandle(stdin_parent);
CloseHandle(stdout_parent);
return -1;
}
pid = GetProcessId(pi.hProcess);
CloseHandle(pi.hThread);
DPRINTF(3, "===============================\n");
DPRINTF(3, "pipes: %lx/%lx\n", (long)stdin_parent, (long)stdout_parent);
DPRINTF(3, "proc: %lx\n", (long)pi.hProcess);
DPRINTF(3, "===============================\n");
if (add_client(conf, (socket_t)stdout_parent,
(socket_t)stdin_parent, pi.hProcess))
{
CloseHandle(stdin_parent);