Annotation of src/usr.bin/nc/socks.c, Revision 1.22
1.22 ! mmcc 1: /* $OpenBSD: socks.c,v 1.21 2015/03/26 21:19:51 tobias Exp $ */
1.1 jakob 2:
3: /*
4: * Copyright (c) 1999 Niklas Hallqvist. All rights reserved.
1.14 djm 5: * Copyright (c) 2004, 2005 Damien Miller. All rights reserved.
1.1 jakob 6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: *
16: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26: */
27:
28: #include <sys/types.h>
29: #include <sys/socket.h>
30: #include <netinet/in.h>
31: #include <arpa/inet.h>
32:
33: #include <err.h>
1.9 djm 34: #include <errno.h>
1.1 jakob 35: #include <netdb.h>
36: #include <stdio.h>
37: #include <stdlib.h>
38: #include <string.h>
39: #include <unistd.h>
1.16 djm 40: #include <resolv.h>
41: #include <readpassphrase.h>
1.15 avsm 42: #include "atomicio.h"
1.1 jakob 43:
44: #define SOCKS_PORT "1080"
1.9 djm 45: #define HTTP_PROXY_PORT "3128"
46: #define HTTP_MAXHDRS 64
1.5 markus 47: #define SOCKS_V5 5
48: #define SOCKS_V4 4
1.1 jakob 49: #define SOCKS_NOAUTH 0
50: #define SOCKS_NOMETHOD 0xff
51: #define SOCKS_CONNECT 1
52: #define SOCKS_IPV4 1
1.14 djm 53: #define SOCKS_DOMAIN 3
54: #define SOCKS_IPV6 4
1.9 djm 55:
1.10 otto 56: int remote_connect(const char *, const char *, struct addrinfo);
1.16 djm 57: int socks_connect(const char *, const char *, struct addrinfo,
58: const char *, const char *, struct addrinfo, int,
59: const char *);
1.1 jakob 60:
1.14 djm 61: static int
62: decode_addrport(const char *h, const char *p, struct sockaddr *addr,
63: socklen_t addrlen, int v4only, int numeric)
1.1 jakob 64: {
1.14 djm 65: int r;
66: struct addrinfo hints, *res;
1.1 jakob 67:
1.14 djm 68: bzero(&hints, sizeof(hints));
69: hints.ai_family = v4only ? PF_INET : PF_UNSPEC;
70: hints.ai_flags = numeric ? AI_NUMERICHOST : 0;
71: hints.ai_socktype = SOCK_STREAM;
72: r = getaddrinfo(h, p, &hints, &res);
73: /* Don't fatal when attempting to convert a numeric address */
74: if (r != 0) {
75: if (!numeric) {
76: errx(1, "getaddrinfo(\"%.64s\", \"%.64s\"): %s", h, p,
77: gai_strerror(r));
78: }
79: return (-1);
80: }
81: if (addrlen < res->ai_addrlen) {
82: freeaddrinfo(res);
83: errx(1, "internal error: addrlen < res->ai_addrlen");
1.1 jakob 84: }
1.14 djm 85: memcpy(addr, res->ai_addr, res->ai_addrlen);
86: freeaddrinfo(res);
87: return (0);
1.1 jakob 88: }
89:
1.9 djm 90: static int
1.15 avsm 91: proxy_read_line(int fd, char *buf, size_t bufsz)
1.9 djm 92: {
1.15 avsm 93: size_t off;
1.9 djm 94:
95: for(off = 0;;) {
96: if (off >= bufsz)
97: errx(1, "proxy read too long");
1.15 avsm 98: if (atomicio(read, fd, buf + off, 1) != 1)
1.9 djm 99: err(1, "proxy read");
100: /* Skip CR */
101: if (buf[off] == '\r')
102: continue;
103: if (buf[off] == '\n') {
104: buf[off] = '\0';
105: break;
106: }
107: off++;
108: }
109: return (off);
110: }
111:
1.16 djm 112: static const char *
113: getproxypass(const char *proxyuser, const char *proxyhost)
114: {
115: char prompt[512];
116: static char pw[256];
117:
118: snprintf(prompt, sizeof(prompt), "Proxy password for %s@%s: ",
119: proxyuser, proxyhost);
120: if (readpassphrase(prompt, pw, sizeof(pw), RPP_REQUIRE_TTY) == NULL)
121: errx(1, "Unable to read proxy passphrase");
122: return (pw);
123: }
124:
1.22 ! mmcc 125: /*
! 126: * Error strings adapted from the generally accepted SOCKSv4 spec:
! 127: *
! 128: * http://ftp.icm.edu.pl/packages/socks/socks4/SOCKS4.protocol
! 129: */
! 130: static const char *
! 131: socks4_strerror(int e)
! 132: {
! 133: switch (e) {
! 134: case 90:
! 135: return "Succeeded";
! 136: case 91:
! 137: return "Request rejected or failed";
! 138: case 92:
! 139: return "SOCKS server cannot connect to identd on the client";
! 140: case 93:
! 141: return "Client program and identd report different user-ids";
! 142: default:
! 143: return "Unknown error";
! 144: }
! 145: }
! 146:
! 147: /*
! 148: * Error strings taken almost directly from RFC 1928.
! 149: */
! 150: static const char *
! 151: socks5_strerror(int e)
! 152: {
! 153: switch (e) {
! 154: case 0:
! 155: return "Succeeded";
! 156: case 1:
! 157: return "General SOCKS server failure";
! 158: case 2:
! 159: return "Connection not allowed by ruleset";
! 160: case 3:
! 161: return "Network unreachable";
! 162: case 4:
! 163: return "Host unreachable";
! 164: case 5:
! 165: return "Connection refused";
! 166: case 6:
! 167: return "TTL expired";
! 168: case 7:
! 169: return "Command not supported";
! 170: case 8:
! 171: return "Address type not supported";
! 172: default:
! 173: return "Unknown error";
! 174: }
! 175: }
! 176:
1.1 jakob 177: int
1.10 otto 178: socks_connect(const char *host, const char *port,
179: struct addrinfo hints __attribute__ ((__unused__)),
180: const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
1.16 djm 181: int socksv, const char *proxyuser)
1.1 jakob 182: {
1.16 djm 183: int proxyfd, r, authretry = 0;
1.14 djm 184: size_t hlen, wlen;
1.9 djm 185: unsigned char buf[1024];
1.15 avsm 186: size_t cnt;
1.14 djm 187: struct sockaddr_storage addr;
188: struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
189: struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
1.1 jakob 190: in_port_t serverport;
1.16 djm 191: const char *proxypass = NULL;
1.1 jakob 192:
1.9 djm 193: if (proxyport == NULL)
194: proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
195:
1.14 djm 196: /* Abuse API to lookup port */
197: if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
198: sizeof(addr), 1, 1) == -1)
199: errx(1, "unknown port \"%.64s\"", port);
200: serverport = in4->sin_port;
1.1 jakob 201:
1.16 djm 202: again:
203: if (authretry++ > 3)
204: errx(1, "Too many authentication failures");
205:
206: proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
207:
208: if (proxyfd < 0)
209: return (-1);
210:
1.5 markus 211: if (socksv == 5) {
1.14 djm 212: if (decode_addrport(host, port, (struct sockaddr *)&addr,
213: sizeof(addr), 0, 1) == -1)
214: addr.ss_family = 0; /* used in switch below */
215:
1.5 markus 216: /* Version 5, one method: no authentication */
217: buf[0] = SOCKS_V5;
218: buf[1] = 1;
219: buf[2] = SOCKS_NOAUTH;
1.15 avsm 220: cnt = atomicio(vwrite, proxyfd, buf, 3);
1.5 markus 221: if (cnt != 3)
1.18 nicm 222: err(1, "write failed (%zu/3)", cnt);
1.15 avsm 223:
224: cnt = atomicio(read, proxyfd, buf, 2);
225: if (cnt != 2)
1.18 nicm 226: err(1, "read failed (%zu/3)", cnt);
1.5 markus 227:
228: if (buf[1] == SOCKS_NOMETHOD)
1.11 djm 229: errx(1, "authentication method negotiation failed");
1.5 markus 230:
1.14 djm 231: switch (addr.ss_family) {
232: case 0:
233: /* Version 5, connect: domain name */
234:
235: /* Max domain name length is 255 bytes */
236: hlen = strlen(host);
237: if (hlen > 255)
238: errx(1, "host name too long for SOCKS5");
239: buf[0] = SOCKS_V5;
240: buf[1] = SOCKS_CONNECT;
241: buf[2] = 0;
242: buf[3] = SOCKS_DOMAIN;
243: buf[4] = hlen;
244: memcpy(buf + 5, host, hlen);
245: memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
246: wlen = 7 + hlen;
247: break;
248: case AF_INET:
249: /* Version 5, connect: IPv4 address */
250: buf[0] = SOCKS_V5;
251: buf[1] = SOCKS_CONNECT;
252: buf[2] = 0;
253: buf[3] = SOCKS_IPV4;
254: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
255: memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
256: wlen = 10;
257: break;
258: case AF_INET6:
259: /* Version 5, connect: IPv6 address */
260: buf[0] = SOCKS_V5;
261: buf[1] = SOCKS_CONNECT;
262: buf[2] = 0;
263: buf[3] = SOCKS_IPV6;
264: memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
265: memcpy(buf + 20, &in6->sin6_port,
266: sizeof in6->sin6_port);
267: wlen = 22;
268: break;
269: default:
270: errx(1, "internal error: silly AF");
271: }
1.5 markus 272:
1.15 avsm 273: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 274: if (cnt != wlen)
1.18 nicm 275: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 276:
1.19 okan 277: cnt = atomicio(read, proxyfd, buf, 4);
278: if (cnt != 4)
279: err(1, "read failed (%zu/4)", cnt);
1.22 ! mmcc 280: if (buf[1] != 0) {
! 281: errx(1, "connection failed, SOCKS error: %s",
! 282: socks5_strerror(buf[1]));
! 283: }
1.19 okan 284: switch (buf[3]) {
285: case SOCKS_IPV4:
286: cnt = atomicio(read, proxyfd, buf + 4, 6);
287: if (cnt != 6)
1.20 espie 288: err(1, "read failed (%zu/6)", cnt);
1.19 okan 289: break;
290: case SOCKS_IPV6:
291: cnt = atomicio(read, proxyfd, buf + 4, 18);
292: if (cnt != 18)
1.20 espie 293: err(1, "read failed (%zu/18)", cnt);
1.19 okan 294: break;
295: default:
296: errx(1, "connection failed, unsupported address type");
297: }
1.9 djm 298: } else if (socksv == 4) {
1.14 djm 299: /* This will exit on lookup failure */
300: decode_addrport(host, port, (struct sockaddr *)&addr,
301: sizeof(addr), 1, 0);
302:
1.5 markus 303: /* Version 4 */
304: buf[0] = SOCKS_V4;
305: buf[1] = SOCKS_CONNECT; /* connect */
1.14 djm 306: memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
307: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
1.5 markus 308: buf[8] = 0; /* empty username */
1.14 djm 309: wlen = 9;
1.5 markus 310:
1.15 avsm 311: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 312: if (cnt != wlen)
1.18 nicm 313: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 314:
1.14 djm 315: cnt = atomicio(read, proxyfd, buf, 8);
1.5 markus 316: if (cnt != 8)
1.18 nicm 317: err(1, "read failed (%zu/8)", cnt);
1.22 ! mmcc 318: if (buf[1] != 90) {
! 319: errx(1, "connection failed, SOCKS error: %s",
! 320: socks4_strerror(buf[1]));
! 321: }
1.9 djm 322: } else if (socksv == -1) {
323: /* HTTP proxy CONNECT */
324:
325: /* Disallow bad chars in hostname */
326: if (strcspn(host, "\r\n\t []:") != strlen(host))
1.11 djm 327: errx(1, "Invalid hostname");
1.9 djm 328:
329: /* Try to be sane about numeric IPv6 addresses */
330: if (strchr(host, ':') != NULL) {
331: r = snprintf(buf, sizeof(buf),
1.16 djm 332: "CONNECT [%s]:%d HTTP/1.0\r\n",
1.9 djm 333: host, ntohs(serverport));
334: } else {
335: r = snprintf(buf, sizeof(buf),
1.16 djm 336: "CONNECT %s:%d HTTP/1.0\r\n",
1.9 djm 337: host, ntohs(serverport));
338: }
1.10 otto 339: if (r == -1 || (size_t)r >= sizeof(buf))
1.11 djm 340: errx(1, "hostname too long");
1.9 djm 341: r = strlen(buf);
342:
1.15 avsm 343: cnt = atomicio(vwrite, proxyfd, buf, r);
1.9 djm 344: if (cnt != r)
1.18 nicm 345: err(1, "write failed (%zu/%d)", cnt, r);
1.9 djm 346:
1.16 djm 347: if (authretry > 1) {
348: char resp[1024];
349:
350: proxypass = getproxypass(proxyuser, proxyhost);
351: r = snprintf(buf, sizeof(buf), "%s:%s",
352: proxyuser, proxypass);
353: if (r == -1 || (size_t)r >= sizeof(buf) ||
354: b64_ntop(buf, strlen(buf), resp,
355: sizeof(resp)) == -1)
356: errx(1, "Proxy username/password too long");
357: r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
358: "Basic %s\r\n", resp);
359: if (r == -1 || (size_t)r >= sizeof(buf))
360: errx(1, "Proxy auth response too long");
361: r = strlen(buf);
362: if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != r)
1.18 nicm 363: err(1, "write failed (%zu/%d)", cnt, r);
1.16 djm 364: }
365:
366: /* Terminate headers */
1.21 tobias 367: if ((cnt = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
368: err(1, "write failed (%zu/2)", cnt);
1.16 djm 369:
370: /* Read status reply */
371: proxy_read_line(proxyfd, buf, sizeof(buf));
372: if (proxyuser != NULL &&
373: strncmp(buf, "HTTP/1.0 407 ", 12) == 0) {
374: if (authretry > 1) {
375: fprintf(stderr, "Proxy authentication "
376: "failed\n");
377: }
378: close(proxyfd);
379: goto again;
1.17 ray 380: } else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
381: strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
1.16 djm 382: errx(1, "Proxy error: \"%s\"", buf);
383:
384: /* Headers continue until we hit an empty line */
1.9 djm 385: for (r = 0; r < HTTP_MAXHDRS; r++) {
386: proxy_read_line(proxyfd, buf, sizeof(buf));
387: if (*buf == '\0')
388: break;
389: }
1.16 djm 390: if (*buf != '\0')
391: errx(1, "Too many proxy headers received");
1.9 djm 392: } else
1.11 djm 393: errx(1, "Unknown proxy protocol %d", socksv);
1.1 jakob 394:
1.11 djm 395: return (proxyfd);
1.1 jakob 396: }
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