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-rw-r--r--usr.bin/nc/socks.c400
1 files changed, 400 insertions, 0 deletions
diff --git a/usr.bin/nc/socks.c b/usr.bin/nc/socks.c
new file mode 100644
index 0000000..9766be7
--- /dev/null
+++ b/usr.bin/nc/socks.c
@@ -0,0 +1,400 @@
+/* $OpenBSD: socks.c,v 1.30 2019/11/04 17:33:28 millert Exp $ */
+
+/*
+ * Copyright (c) 1999 Niklas Hallqvist. All rights reserved.
+ * Copyright (c) 2004, 2005 Damien Miller. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <err.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <resolv.h>
+#include <readpassphrase.h>
+#include "atomicio.h"
+
+#define SOCKS_PORT "1080"
+#define HTTP_PROXY_PORT "3128"
+#define HTTP_MAXHDRS 64
+#define SOCKS_V5 5
+#define SOCKS_V4 4
+#define SOCKS_NOAUTH 0
+#define SOCKS_NOMETHOD 0xff
+#define SOCKS_CONNECT 1
+#define SOCKS_IPV4 1
+#define SOCKS_DOMAIN 3
+#define SOCKS_IPV6 4
+
+int remote_connect(const char *, const char *, struct addrinfo, char *);
+int socks_connect(const char *, const char *, struct addrinfo,
+ const char *, const char *, struct addrinfo, int,
+ const char *);
+
+static int
+decode_addrport(const char *h, const char *p, struct sockaddr *addr,
+ socklen_t addrlen, int v4only, int numeric)
+{
+ int r;
+ struct addrinfo hints, *res;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = v4only ? PF_INET : PF_UNSPEC;
+ hints.ai_flags = numeric ? AI_NUMERICHOST : 0;
+ hints.ai_socktype = SOCK_STREAM;
+ r = getaddrinfo(h, p, &hints, &res);
+ /* Don't fatal when attempting to convert a numeric address */
+ if (r != 0) {
+ if (!numeric) {
+ errx(1, "getaddrinfo(\"%.64s\", \"%.64s\"): %s", h, p,
+ gai_strerror(r));
+ }
+ return (-1);
+ }
+ if (addrlen < res->ai_addrlen) {
+ freeaddrinfo(res);
+ errx(1, "internal error: addrlen < res->ai_addrlen");
+ }
+ memcpy(addr, res->ai_addr, res->ai_addrlen);
+ freeaddrinfo(res);
+ return (0);
+}
+
+static int
+proxy_read_line(int fd, char *buf, size_t bufsz)
+{
+ size_t off;
+
+ for(off = 0;;) {
+ if (off >= bufsz)
+ errx(1, "proxy read too long");
+ if (atomicio(read, fd, buf + off, 1) != 1)
+ err(1, "proxy read");
+ /* Skip CR */
+ if (buf[off] == '\r')
+ continue;
+ if (buf[off] == '\n') {
+ buf[off] = '\0';
+ break;
+ }
+ off++;
+ }
+ return (off);
+}
+
+static void
+getproxypass(const char *proxyuser, const char *proxyhost,
+ char *pw, size_t pwlen)
+{
+ char prompt[512];
+
+ snprintf(prompt, sizeof(prompt), "Proxy password for %s@%s: ",
+ proxyuser, proxyhost);
+ if (readpassphrase(prompt, pw, pwlen, RPP_REQUIRE_TTY) == NULL)
+ errx(1, "Unable to read proxy passphrase");
+}
+
+/*
+ * Error strings adapted from the generally accepted SOCKSv4 spec:
+ *
+ * http://ftp.icm.edu.pl/packages/socks/socks4/SOCKS4.protocol
+ */
+static const char *
+socks4_strerror(int e)
+{
+ switch (e) {
+ case 90:
+ return "Succeeded";
+ case 91:
+ return "Request rejected or failed";
+ case 92:
+ return "SOCKS server cannot connect to identd on the client";
+ case 93:
+ return "Client program and identd report different user-ids";
+ default:
+ return "Unknown error";
+ }
+}
+
+/*
+ * Error strings taken almost directly from RFC 1928.
+ */
+static const char *
+socks5_strerror(int e)
+{
+ switch (e) {
+ case 0:
+ return "Succeeded";
+ case 1:
+ return "General SOCKS server failure";
+ case 2:
+ return "Connection not allowed by ruleset";
+ case 3:
+ return "Network unreachable";
+ case 4:
+ return "Host unreachable";
+ case 5:
+ return "Connection refused";
+ case 6:
+ return "TTL expired";
+ case 7:
+ return "Command not supported";
+ case 8:
+ return "Address type not supported";
+ default:
+ return "Unknown error";
+ }
+}
+
+int
+socks_connect(const char *host, const char *port,
+ struct addrinfo hints __attribute__ ((__unused__)),
+ const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
+ int socksv, const char *proxyuser)
+{
+ int proxyfd, r, authretry = 0;
+ size_t hlen, wlen;
+ unsigned char buf[1024];
+ size_t cnt;
+ struct sockaddr_storage addr;
+ struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
+ struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
+ in_port_t serverport;
+
+ if (proxyport == NULL)
+ proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
+
+ /* Abuse API to lookup port */
+ if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
+ sizeof(addr), 1, 1) == -1)
+ errx(1, "unknown port \"%.64s\"", port);
+ serverport = in4->sin_port;
+
+ again:
+ if (authretry++ > 3)
+ errx(1, "Too many authentication failures");
+
+ proxyfd = remote_connect(proxyhost, proxyport, proxyhints, NULL);
+
+ if (proxyfd < 0)
+ return (-1);
+
+ if (socksv == 5) {
+ if (decode_addrport(host, port, (struct sockaddr *)&addr,
+ sizeof(addr), 0, 1) == -1)
+ addr.ss_family = 0; /* used in switch below */
+
+ /* Version 5, one method: no authentication */
+ buf[0] = SOCKS_V5;
+ buf[1] = 1;
+ buf[2] = SOCKS_NOAUTH;
+ cnt = atomicio(vwrite, proxyfd, buf, 3);
+ if (cnt != 3)
+ err(1, "write failed (%zu/3)", cnt);
+
+ cnt = atomicio(read, proxyfd, buf, 2);
+ if (cnt != 2)
+ err(1, "read failed (%zu/3)", cnt);
+
+ if (buf[1] == SOCKS_NOMETHOD)
+ errx(1, "authentication method negotiation failed");
+
+ switch (addr.ss_family) {
+ case 0:
+ /* Version 5, connect: domain name */
+
+ /* Max domain name length is 255 bytes */
+ hlen = strlen(host);
+ if (hlen > 255)
+ errx(1, "host name too long for SOCKS5");
+ buf[0] = SOCKS_V5;
+ buf[1] = SOCKS_CONNECT;
+ buf[2] = 0;
+ buf[3] = SOCKS_DOMAIN;
+ buf[4] = hlen;
+ memcpy(buf + 5, host, hlen);
+ memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
+ wlen = 7 + hlen;
+ break;
+ case AF_INET:
+ /* Version 5, connect: IPv4 address */
+ buf[0] = SOCKS_V5;
+ buf[1] = SOCKS_CONNECT;
+ buf[2] = 0;
+ buf[3] = SOCKS_IPV4;
+ memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
+ memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
+ wlen = 10;
+ break;
+ case AF_INET6:
+ /* Version 5, connect: IPv6 address */
+ buf[0] = SOCKS_V5;
+ buf[1] = SOCKS_CONNECT;
+ buf[2] = 0;
+ buf[3] = SOCKS_IPV6;
+ memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
+ memcpy(buf + 20, &in6->sin6_port,
+ sizeof in6->sin6_port);
+ wlen = 22;
+ break;
+ default:
+ errx(1, "internal error: silly AF");
+ }
+
+ cnt = atomicio(vwrite, proxyfd, buf, wlen);
+ if (cnt != wlen)
+ err(1, "write failed (%zu/%zu)", cnt, wlen);
+
+ cnt = atomicio(read, proxyfd, buf, 4);
+ if (cnt != 4)
+ err(1, "read failed (%zu/4)", cnt);
+ if (buf[1] != 0) {
+ errx(1, "connection failed, SOCKSv5 error: %s",
+ socks5_strerror(buf[1]));
+ }
+ switch (buf[3]) {
+ case SOCKS_IPV4:
+ cnt = atomicio(read, proxyfd, buf + 4, 6);
+ if (cnt != 6)
+ err(1, "read failed (%zu/6)", cnt);
+ break;
+ case SOCKS_IPV6:
+ cnt = atomicio(read, proxyfd, buf + 4, 18);
+ if (cnt != 18)
+ err(1, "read failed (%zu/18)", cnt);
+ break;
+ default:
+ errx(1, "connection failed, unsupported address type");
+ }
+ } else if (socksv == 4) {
+ /* This will exit on lookup failure */
+ decode_addrport(host, port, (struct sockaddr *)&addr,
+ sizeof(addr), 1, 0);
+
+ /* Version 4 */
+ buf[0] = SOCKS_V4;
+ buf[1] = SOCKS_CONNECT; /* connect */
+ memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
+ memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
+ buf[8] = 0; /* empty username */
+ wlen = 9;
+
+ cnt = atomicio(vwrite, proxyfd, buf, wlen);
+ if (cnt != wlen)
+ err(1, "write failed (%zu/%zu)", cnt, wlen);
+
+ cnt = atomicio(read, proxyfd, buf, 8);
+ if (cnt != 8)
+ err(1, "read failed (%zu/8)", cnt);
+ if (buf[1] != 90) {
+ errx(1, "connection failed, SOCKSv4 error: %s",
+ socks4_strerror(buf[1]));
+ }
+ } else if (socksv == -1) {
+ /* HTTP proxy CONNECT */
+
+ /* Disallow bad chars in hostname */
+ if (strcspn(host, "\r\n\t []:") != strlen(host))
+ errx(1, "Invalid hostname");
+
+ /* Try to be sane about numeric IPv6 addresses */
+ if (strchr(host, ':') != NULL) {
+ r = snprintf(buf, sizeof(buf),
+ "CONNECT [%s]:%d HTTP/1.0\r\n",
+ host, ntohs(serverport));
+ } else {
+ r = snprintf(buf, sizeof(buf),
+ "CONNECT %s:%d HTTP/1.0\r\n",
+ host, ntohs(serverport));
+ }
+ if (r < 0 || (size_t)r >= sizeof(buf))
+ errx(1, "hostname too long");
+ r = strlen(buf);
+
+ cnt = atomicio(vwrite, proxyfd, buf, r);
+ if (cnt != r)
+ err(1, "write failed (%zu/%d)", cnt, r);
+
+ if (authretry > 1) {
+ char proxypass[256];
+ char resp[1024];
+
+ getproxypass(proxyuser, proxyhost,
+ proxypass, sizeof proxypass);
+ r = snprintf(buf, sizeof(buf), "%s:%s",
+ proxyuser, proxypass);
+ explicit_bzero(proxypass, sizeof proxypass);
+ if (r == -1 || (size_t)r >= sizeof(buf) ||
+ b64_ntop(buf, strlen(buf), resp,
+ sizeof(resp)) == -1)
+ errx(1, "Proxy username/password too long");
+ r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
+ "Basic %s\r\n", resp);
+ if (r < 0 || (size_t)r >= sizeof(buf))
+ errx(1, "Proxy auth response too long");
+ r = strlen(buf);
+ if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != r)
+ err(1, "write failed (%zu/%d)", cnt, r);
+ explicit_bzero(proxypass, sizeof proxypass);
+ explicit_bzero(buf, sizeof buf);
+ }
+
+ /* Terminate headers */
+ if ((cnt = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
+ err(1, "write failed (%zu/2)", cnt);
+
+ /* Read status reply */
+ proxy_read_line(proxyfd, buf, sizeof(buf));
+ if (proxyuser != NULL &&
+ (strncmp(buf, "HTTP/1.0 407 ", 12) == 0 ||
+ strncmp(buf, "HTTP/1.1 407 ", 12) == 0)) {
+ if (authretry > 1) {
+ fprintf(stderr, "Proxy authentication "
+ "failed\n");
+ }
+ close(proxyfd);
+ goto again;
+ } else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
+ strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
+ errx(1, "Proxy error: \"%s\"", buf);
+
+ /* Headers continue until we hit an empty line */
+ for (r = 0; r < HTTP_MAXHDRS; r++) {
+ proxy_read_line(proxyfd, buf, sizeof(buf));
+ if (*buf == '\0')
+ break;
+ }
+ if (*buf != '\0')
+ errx(1, "Too many proxy headers received");
+ } else
+ errx(1, "Unknown proxy protocol %d", socksv);
+
+ return (proxyfd);
+}
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