341 lines
9.6 KiB
C
341 lines
9.6 KiB
C
/* $OpenBSD: socks.c,v 1.19 2011/02/12 15:54:18 okan Exp $ */
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/*
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* Copyright (c) 1999 Niklas Hallqvist. All rights reserved.
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* Copyright (c) 2004, 2005 Damien Miller. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <err.h>
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#include <errno.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <resolv.h>
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#include <readpassphrase.h>
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#include "atomicio.h"
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#define SOCKS_PORT "1080"
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#define HTTP_PROXY_PORT "3128"
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#define HTTP_MAXHDRS 64
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#define SOCKS_V5 5
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#define SOCKS_V4 4
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#define SOCKS_NOAUTH 0
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#define SOCKS_NOMETHOD 0xff
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#define SOCKS_CONNECT 1
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#define SOCKS_IPV4 1
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#define SOCKS_DOMAIN 3
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#define SOCKS_IPV6 4
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int remote_connect(const char *, const char *, struct addrinfo);
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int socks_connect(const char *, const char *, struct addrinfo,
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const char *, const char *, struct addrinfo, int,
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const char *);
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static int
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decode_addrport(const char *h, const char *p, struct sockaddr *addr,
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socklen_t addrlen, int v4only, int numeric)
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{
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int r;
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struct addrinfo hints, *res;
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bzero(&hints, sizeof(hints));
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hints.ai_family = v4only ? PF_INET : PF_UNSPEC;
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hints.ai_flags = numeric ? AI_NUMERICHOST : 0;
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hints.ai_socktype = SOCK_STREAM;
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r = getaddrinfo(h, p, &hints, &res);
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/* Don't fatal when attempting to convert a numeric address */
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if (r != 0) {
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if (!numeric) {
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errx(1, "getaddrinfo(\"%.64s\", \"%.64s\"): %s", h, p,
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gai_strerror(r));
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}
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return (-1);
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}
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if (addrlen < res->ai_addrlen) {
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freeaddrinfo(res);
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errx(1, "internal error: addrlen < res->ai_addrlen");
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}
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memcpy(addr, res->ai_addr, res->ai_addrlen);
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freeaddrinfo(res);
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return (0);
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}
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static int
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proxy_read_line(int fd, char *buf, size_t bufsz)
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{
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size_t off;
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for(off = 0;;) {
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if (off >= bufsz)
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errx(1, "proxy read too long");
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if (atomicio(read, fd, buf + off, 1) != 1)
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err(1, "proxy read");
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/* Skip CR */
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if (buf[off] == '\r')
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continue;
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if (buf[off] == '\n') {
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buf[off] = '\0';
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break;
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}
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off++;
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}
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return (off);
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}
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static const char *
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getproxypass(const char *proxyuser, const char *proxyhost)
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{
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char prompt[512];
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static char pw[256];
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snprintf(prompt, sizeof(prompt), "Proxy password for %s@%s: ",
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proxyuser, proxyhost);
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if (readpassphrase(prompt, pw, sizeof(pw), RPP_REQUIRE_TTY) == NULL)
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errx(1, "Unable to read proxy passphrase");
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return (pw);
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}
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int
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socks_connect(const char *host, const char *port,
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struct addrinfo hints __attribute__ ((__unused__)),
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const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
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int socksv, const char *proxyuser)
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{
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int proxyfd, r, authretry = 0;
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size_t hlen, wlen;
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unsigned char buf[1024];
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size_t cnt;
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struct sockaddr_storage addr;
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struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
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struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
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in_port_t serverport;
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const char *proxypass = NULL;
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if (proxyport == NULL)
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proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
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/* Abuse API to lookup port */
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if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
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sizeof(addr), 1, 1) == -1)
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errx(1, "unknown port \"%.64s\"", port);
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serverport = in4->sin_port;
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again:
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if (authretry++ > 3)
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errx(1, "Too many authentication failures");
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proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
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if (proxyfd < 0)
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return (-1);
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if (socksv == 5) {
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if (decode_addrport(host, port, (struct sockaddr *)&addr,
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sizeof(addr), 0, 1) == -1)
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addr.ss_family = 0; /* used in switch below */
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/* Version 5, one method: no authentication */
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buf[0] = SOCKS_V5;
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buf[1] = 1;
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buf[2] = SOCKS_NOAUTH;
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cnt = atomicio(vwrite, proxyfd, buf, 3);
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if (cnt != 3)
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err(1, "write failed (%zu/3)", cnt);
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cnt = atomicio(read, proxyfd, buf, 2);
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if (cnt != 2)
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err(1, "read failed (%zu/3)", cnt);
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if (buf[1] == SOCKS_NOMETHOD)
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errx(1, "authentication method negotiation failed");
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switch (addr.ss_family) {
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case 0:
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/* Version 5, connect: domain name */
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/* Max domain name length is 255 bytes */
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hlen = strlen(host);
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if (hlen > 255)
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errx(1, "host name too long for SOCKS5");
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buf[0] = SOCKS_V5;
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buf[1] = SOCKS_CONNECT;
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buf[2] = 0;
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buf[3] = SOCKS_DOMAIN;
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buf[4] = hlen;
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memcpy(buf + 5, host, hlen);
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memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
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wlen = 7 + hlen;
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break;
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case AF_INET:
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/* Version 5, connect: IPv4 address */
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buf[0] = SOCKS_V5;
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buf[1] = SOCKS_CONNECT;
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buf[2] = 0;
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buf[3] = SOCKS_IPV4;
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memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
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memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
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wlen = 10;
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break;
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case AF_INET6:
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/* Version 5, connect: IPv6 address */
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buf[0] = SOCKS_V5;
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buf[1] = SOCKS_CONNECT;
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buf[2] = 0;
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buf[3] = SOCKS_IPV6;
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memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
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memcpy(buf + 20, &in6->sin6_port,
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sizeof in6->sin6_port);
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wlen = 22;
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break;
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default:
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errx(1, "internal error: silly AF");
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}
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cnt = atomicio(vwrite, proxyfd, buf, wlen);
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if (cnt != wlen)
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err(1, "write failed (%zu/%zu)", cnt, wlen);
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cnt = atomicio(read, proxyfd, buf, 4);
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if (cnt != 4)
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err(1, "read failed (%zu/4)", cnt);
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if (buf[1] != 0)
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errx(1, "connection failed, SOCKS error %d", buf[1]);
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switch (buf[3]) {
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case SOCKS_IPV4:
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cnt = atomicio(read, proxyfd, buf + 4, 6);
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if (cnt != 6)
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err(1, "read failed (%zd/6)", cnt);
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break;
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case SOCKS_IPV6:
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cnt = atomicio(read, proxyfd, buf + 4, 18);
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if (cnt != 18)
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err(1, "read failed (%zd/18)", cnt);
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break;
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default:
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errx(1, "connection failed, unsupported address type");
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}
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} else if (socksv == 4) {
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/* This will exit on lookup failure */
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decode_addrport(host, port, (struct sockaddr *)&addr,
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sizeof(addr), 1, 0);
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/* Version 4 */
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buf[0] = SOCKS_V4;
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buf[1] = SOCKS_CONNECT; /* connect */
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memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
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memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
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buf[8] = 0; /* empty username */
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wlen = 9;
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cnt = atomicio(vwrite, proxyfd, buf, wlen);
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if (cnt != wlen)
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err(1, "write failed (%zu/%zu)", cnt, wlen);
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cnt = atomicio(read, proxyfd, buf, 8);
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if (cnt != 8)
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err(1, "read failed (%zu/8)", cnt);
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if (buf[1] != 90)
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errx(1, "connection failed, SOCKS error %d", buf[1]);
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} else if (socksv == -1) {
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/* HTTP proxy CONNECT */
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/* Disallow bad chars in hostname */
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if (strcspn(host, "\r\n\t []:") != strlen(host))
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errx(1, "Invalid hostname");
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/* Try to be sane about numeric IPv6 addresses */
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if (strchr(host, ':') != NULL) {
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r = snprintf(buf, sizeof(buf),
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"CONNECT [%s]:%d HTTP/1.0\r\n",
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host, ntohs(serverport));
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} else {
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r = snprintf(buf, sizeof(buf),
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"CONNECT %s:%d HTTP/1.0\r\n",
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host, ntohs(serverport));
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}
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if (r == -1 || (size_t)r >= sizeof(buf))
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errx(1, "hostname too long");
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r = strlen(buf);
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cnt = atomicio(vwrite, proxyfd, buf, r);
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if (cnt != r)
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err(1, "write failed (%zu/%d)", cnt, r);
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if (authretry > 1) {
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char resp[1024];
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proxypass = getproxypass(proxyuser, proxyhost);
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r = snprintf(buf, sizeof(buf), "%s:%s",
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proxyuser, proxypass);
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if (r == -1 || (size_t)r >= sizeof(buf) ||
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b64_ntop(buf, strlen(buf), resp,
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sizeof(resp)) == -1)
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errx(1, "Proxy username/password too long");
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r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
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"Basic %s\r\n", resp);
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if (r == -1 || (size_t)r >= sizeof(buf))
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errx(1, "Proxy auth response too long");
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r = strlen(buf);
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if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != r)
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err(1, "write failed (%zu/%d)", cnt, r);
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}
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/* Terminate headers */
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if ((r = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
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err(1, "write failed (2/%d)", r);
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/* Read status reply */
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proxy_read_line(proxyfd, buf, sizeof(buf));
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if (proxyuser != NULL &&
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strncmp(buf, "HTTP/1.0 407 ", 12) == 0) {
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if (authretry > 1) {
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fprintf(stderr, "Proxy authentication "
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"failed\n");
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}
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close(proxyfd);
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goto again;
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} else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
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strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
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errx(1, "Proxy error: \"%s\"", buf);
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/* Headers continue until we hit an empty line */
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for (r = 0; r < HTTP_MAXHDRS; r++) {
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proxy_read_line(proxyfd, buf, sizeof(buf));
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if (*buf == '\0')
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break;
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}
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if (*buf != '\0')
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errx(1, "Too many proxy headers received");
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} else
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errx(1, "Unknown proxy protocol %d", socksv);
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return (proxyfd);
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}
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