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nmap/nsock/src/proxy_socks4.c
dmiller 6e33d6ac3c Bump date in copyright headers
2016-04-04 15:38:44 +00:00

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/***************************************************************************
* proxy_socks4.c -- SOCKS4 proxying. *
* *
***********************IMPORTANT NSOCK LICENSE TERMS***********************
* *
* The nsock parallel socket event library is (C) 1999-2016 Insecure.Com *
* LLC This library is free software; you may redistribute and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; Version 2. This guarantees *
* your right to use, modify, and redistribute this software under certain *
* conditions. If this license is unacceptable to you, Insecure.Com LLC *
* may be willing to sell alternative licenses (contact *
* sales@insecure.com ). *
* *
* As a special exception to the GPL terms, Insecure.Com LLC grants *
* permission to link the code of this program with any version of the *
* OpenSSL library which is distributed under a license identical to that *
* listed in the included docs/licenses/OpenSSL.txt file, and distribute *
* linked combinations including the two. You must obey the GNU GPL in all *
* respects for all of the code used other than OpenSSL. If you modify *
* this file, you may extend this exception to your version of the file, *
* but you are not obligated to do so. *
* *
* If you received these files with a written license agreement stating *
* terms other than the (GPL) terms above, then that alternative license *
* agreement takes precedence over this comment. *
* *
* Source is provided to this software because we believe users have a *
* right to know exactly what a program is going to do before they run it. *
* This also allows you to audit the software for security holes. *
* *
* Source code also allows you to port Nmap to new platforms, fix bugs, *
* and add new features. You are highly encouraged to send your changes *
* to the dev@nmap.org mailing list for possible incorporation into the *
* main distribution. By sending these changes to Fyodor or one of the *
* Insecure.Org development mailing lists, or checking them into the Nmap *
* source code repository, it is understood (unless you specify otherwise) *
* that you are offering the Nmap Project (Insecure.Com LLC) the *
* unlimited, non-exclusive right to reuse, modify, and relicense the *
* code. Nmap will always be available Open Source, but this is important *
* because the inability to relicense code has caused devastating problems *
* for other Free Software projects (such as KDE and NASM). We also *
* occasionally relicense the code to third parties as discussed above. *
* If you wish to specify special license conditions of your *
* contributions, just say so when you send them. *
* *
* 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 v2.0 for more details *
* (http://www.gnu.org/licenses/gpl-2.0.html). *
* *
***************************************************************************/
/* $Id $ */
#define _GNU_SOURCE
#include <stdio.h>
#include "nsock.h"
#include "nsock_internal.h"
#include "nsock_log.h"
#include <string.h>
#define DEFAULT_PROXY_PORT_SOCKS4 1080
extern struct timeval nsock_tod;
extern const struct proxy_spec ProxySpecSocks4;
struct socks4_data {
uint8_t version;
uint8_t type;
uint16_t port;
uint32_t address;
uint8_t null;
} __attribute__((packed));
static int proxy_socks4_node_new(struct proxy_node **node, const struct uri *uri) {
int rc;
struct proxy_node *proxy;
proxy = (struct proxy_node *)safe_zalloc(sizeof(struct proxy_node));
proxy->spec = &ProxySpecSocks4;
rc = proxy_resolve(uri->host, (struct sockaddr *)&proxy->ss, &proxy->sslen);
if (rc < 0)
goto err_out;
if (proxy->ss.ss_family != AF_INET) {
rc = -1;
goto err_out;
}
if (uri->port == -1)
proxy->port = DEFAULT_PROXY_PORT_SOCKS4;
else
proxy->port = (unsigned short)uri->port;
rc = asprintf(&proxy->nodestr, "socks4://%s:%d", uri->host, proxy->port);
if (rc < 0) {
/* asprintf() failed for some reason but this is not a disaster (yet).
* Set nodestr to NULL and try to keep on going. */
proxy->nodestr = NULL;
}
rc = 1;
err_out:
if (rc < 0) {
free(proxy);
proxy = NULL;
}
*node = proxy;
return rc;
}
static void proxy_socks4_node_delete(struct proxy_node *node) {
if (!node)
return;
free(node->nodestr);
free(node);
}
static inline void socks4_data_init(struct socks4_data *socks4,
struct sockaddr_storage *ss, size_t sslen,
unsigned short port) {
struct sockaddr_in *sin = (struct sockaddr_in *)ss;
memset(socks4, 0x00, sizeof(struct socks4_data));
socks4->version = 4;
socks4->type = 1;
socks4->port = htons(port);
assert(ss->ss_family == AF_INET);
socks4->address = sin->sin_addr.s_addr;
}
static int handle_state_initial(struct npool *nsp, struct nevent *nse, void *udata) {
struct proxy_chain_context *px_ctx = nse->iod->px_ctx;
struct sockaddr_storage *ss;
size_t sslen;
unsigned short port;
struct proxy_node *next;
struct socks4_data socks4;
int timeout;
px_ctx->px_state = PROXY_STATE_SOCKS4_TCP_CONNECTED;
next = proxy_ctx_node_next(px_ctx);
if (next) {
ss = &next->ss;
sslen = next->sslen;
port = next->port;
} else {
ss = &px_ctx->target_ss;
sslen = px_ctx->target_sslen;
port = px_ctx->target_port;
}
socks4_data_init(&socks4, ss, sslen, port);
timeout = TIMEVAL_MSEC_SUBTRACT(nse->timeout, nsock_tod);
nsock_write(nsp, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch, timeout, udata,
(char *)&socks4, sizeof(socks4));
nsock_readbytes(nsp, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch, timeout,
udata, 8);
return 0;
}
static int handle_state_tcp_connected(struct npool *nsp, struct nevent *nse, void *udata) {
struct proxy_chain_context *px_ctx = nse->iod->px_ctx;
char *res;
int reslen;
res = nse_readbuf(nse, &reslen);
if (!(reslen == 8 && res[1] == 90)) {
struct proxy_node *node = px_ctx->px_current;
nsock_log_debug("Ignoring invalid socks4 reply from proxy %s",
node->nodestr);
return -EINVAL;
}
px_ctx->px_state = PROXY_STATE_SOCKS4_TUNNEL_ESTABLISHED;
if (proxy_ctx_node_next(px_ctx) == NULL) {
forward_event(nsp, nse, udata);
} else {
px_ctx->px_current = proxy_ctx_node_next(px_ctx);
px_ctx->px_state = PROXY_STATE_INITIAL;
nsock_proxy_ev_dispatch(nsp, nse, udata);
}
return 0;
}
static void proxy_socks4_handler(nsock_pool nspool, nsock_event nsevent, void *udata) {
int rc = 0;
struct npool *nsp = (struct npool *)nspool;
struct nevent *nse = (struct nevent *)nsevent;
switch (nse->iod->px_ctx->px_state) {
case PROXY_STATE_INITIAL:
rc = handle_state_initial(nsp, nse, udata);
break;
case PROXY_STATE_SOCKS4_TCP_CONNECTED:
if (nse->type == NSE_TYPE_READ)
rc = handle_state_tcp_connected(nsp, nse, udata);
break;
case PROXY_STATE_SOCKS4_TUNNEL_ESTABLISHED:
forward_event(nsp, nse, udata);
break;
default:
fatal("Invalid proxy state!");
}
if (rc) {
nse->status = NSE_STATUS_PROXYERROR;
forward_event(nsp, nse, udata);
}
}
/* ---- PROXY DEFINITION ---- */
static const struct proxy_op ProxyOpsSocks4 = {
proxy_socks4_node_new,
proxy_socks4_node_delete,
proxy_socks4_handler,
};
const struct proxy_spec ProxySpecSocks4 = {
"socks4://",
PROXY_TYPE_SOCKS4,
&ProxyOpsSocks4,
};
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