From 0d47952611198ef6b1163f366dc03922d20b1475 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 09:42:04 +0200 Subject: Adding upstream version 7.94+git20230807.3be01efb1+dfsg. Signed-off-by: Daniel Baumann --- nsock/src/proxy_socks4.c | 241 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 241 insertions(+) create mode 100644 nsock/src/proxy_socks4.c (limited to 'nsock/src/proxy_socks4.c') diff --git a/nsock/src/proxy_socks4.c b/nsock/src/proxy_socks4.c new file mode 100644 index 0000000..c88ca38 --- /dev/null +++ b/nsock/src/proxy_socks4.c @@ -0,0 +1,241 @@ +/*************************************************************************** + * proxy_socks4.c -- SOCKS4 proxying. * + * * + ***********************IMPORTANT NSOCK LICENSE TERMS*********************** + * + * The nsock parallel socket event library is (C) 1999-2023 Nmap Software 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, Nmap Software LLC may be willing to sell alternative + * licenses (contact sales@nmap.com ). + * + * As a special exception to the GPL terms, Nmap Software 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 (Nmap Software 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 + +#include "nsock.h" +#include "nsock_internal.h" +#include "nsock_log.h" + +#include + +#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, AF_INET); + 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, +}; + -- cgit v1.2.3