Annotation of src/usr.bin/nc/socks.c, Revision 1.29
1.29 ! benno 1: /* $OpenBSD: socks.c,v 1.28 2019/07/03 03:24:02 deraadt 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:
1.27 mestre 68: memset(&hints, 0, sizeof(hints));
1.14 djm 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:
1.25 deraadt 112: static void
113: getproxypass(const char *proxyuser, const char *proxyhost,
114: char *pw, size_t pwlen)
1.16 djm 115: {
116: char prompt[512];
117:
118: snprintf(prompt, sizeof(prompt), "Proxy password for %s@%s: ",
119: proxyuser, proxyhost);
1.25 deraadt 120: if (readpassphrase(prompt, pw, pwlen, RPP_REQUIRE_TTY) == NULL)
1.16 djm 121: errx(1, "Unable to read proxy passphrase");
122: }
123:
1.22 mmcc 124: /*
125: * Error strings adapted from the generally accepted SOCKSv4 spec:
126: *
127: * http://ftp.icm.edu.pl/packages/socks/socks4/SOCKS4.protocol
128: */
129: static const char *
130: socks4_strerror(int e)
131: {
132: switch (e) {
133: case 90:
134: return "Succeeded";
135: case 91:
136: return "Request rejected or failed";
137: case 92:
138: return "SOCKS server cannot connect to identd on the client";
139: case 93:
140: return "Client program and identd report different user-ids";
141: default:
142: return "Unknown error";
143: }
144: }
145:
146: /*
147: * Error strings taken almost directly from RFC 1928.
148: */
149: static const char *
150: socks5_strerror(int e)
151: {
152: switch (e) {
153: case 0:
154: return "Succeeded";
155: case 1:
156: return "General SOCKS server failure";
157: case 2:
158: return "Connection not allowed by ruleset";
159: case 3:
160: return "Network unreachable";
161: case 4:
162: return "Host unreachable";
163: case 5:
164: return "Connection refused";
165: case 6:
166: return "TTL expired";
167: case 7:
168: return "Command not supported";
169: case 8:
170: return "Address type not supported";
171: default:
172: return "Unknown error";
173: }
174: }
175:
1.1 jakob 176: int
1.10 otto 177: socks_connect(const char *host, const char *port,
178: struct addrinfo hints __attribute__ ((__unused__)),
179: const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
1.16 djm 180: int socksv, const char *proxyuser)
1.1 jakob 181: {
1.16 djm 182: int proxyfd, r, authretry = 0;
1.14 djm 183: size_t hlen, wlen;
1.9 djm 184: unsigned char buf[1024];
1.15 avsm 185: size_t cnt;
1.14 djm 186: struct sockaddr_storage addr;
187: struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
188: struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
1.1 jakob 189: in_port_t serverport;
190:
1.9 djm 191: if (proxyport == NULL)
192: proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
193:
1.14 djm 194: /* Abuse API to lookup port */
195: if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
196: sizeof(addr), 1, 1) == -1)
197: errx(1, "unknown port \"%.64s\"", port);
198: serverport = in4->sin_port;
1.1 jakob 199:
1.16 djm 200: again:
201: if (authretry++ > 3)
202: errx(1, "Too many authentication failures");
203:
204: proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
205:
206: if (proxyfd < 0)
207: return (-1);
208:
1.5 markus 209: if (socksv == 5) {
1.14 djm 210: if (decode_addrport(host, port, (struct sockaddr *)&addr,
211: sizeof(addr), 0, 1) == -1)
212: addr.ss_family = 0; /* used in switch below */
213:
1.5 markus 214: /* Version 5, one method: no authentication */
215: buf[0] = SOCKS_V5;
216: buf[1] = 1;
217: buf[2] = SOCKS_NOAUTH;
1.15 avsm 218: cnt = atomicio(vwrite, proxyfd, buf, 3);
1.5 markus 219: if (cnt != 3)
1.18 nicm 220: err(1, "write failed (%zu/3)", cnt);
1.15 avsm 221:
222: cnt = atomicio(read, proxyfd, buf, 2);
223: if (cnt != 2)
1.18 nicm 224: err(1, "read failed (%zu/3)", cnt);
1.5 markus 225:
226: if (buf[1] == SOCKS_NOMETHOD)
1.11 djm 227: errx(1, "authentication method negotiation failed");
1.5 markus 228:
1.14 djm 229: switch (addr.ss_family) {
230: case 0:
231: /* Version 5, connect: domain name */
232:
233: /* Max domain name length is 255 bytes */
234: hlen = strlen(host);
235: if (hlen > 255)
236: errx(1, "host name too long for SOCKS5");
237: buf[0] = SOCKS_V5;
238: buf[1] = SOCKS_CONNECT;
239: buf[2] = 0;
240: buf[3] = SOCKS_DOMAIN;
241: buf[4] = hlen;
1.24 deraadt 242: memcpy(buf + 5, host, hlen);
1.14 djm 243: memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
244: wlen = 7 + hlen;
245: break;
246: case AF_INET:
247: /* Version 5, connect: IPv4 address */
248: buf[0] = SOCKS_V5;
249: buf[1] = SOCKS_CONNECT;
250: buf[2] = 0;
251: buf[3] = SOCKS_IPV4;
252: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
253: memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
254: wlen = 10;
255: break;
256: case AF_INET6:
257: /* Version 5, connect: IPv6 address */
258: buf[0] = SOCKS_V5;
259: buf[1] = SOCKS_CONNECT;
260: buf[2] = 0;
261: buf[3] = SOCKS_IPV6;
262: memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
263: memcpy(buf + 20, &in6->sin6_port,
264: sizeof in6->sin6_port);
265: wlen = 22;
266: break;
267: default:
268: errx(1, "internal error: silly AF");
269: }
1.5 markus 270:
1.15 avsm 271: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 272: if (cnt != wlen)
1.18 nicm 273: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 274:
1.19 okan 275: cnt = atomicio(read, proxyfd, buf, 4);
276: if (cnt != 4)
277: err(1, "read failed (%zu/4)", cnt);
1.22 mmcc 278: if (buf[1] != 0) {
1.23 mmcc 279: errx(1, "connection failed, SOCKSv5 error: %s",
1.22 mmcc 280: socks5_strerror(buf[1]));
281: }
1.19 okan 282: switch (buf[3]) {
283: case SOCKS_IPV4:
284: cnt = atomicio(read, proxyfd, buf + 4, 6);
285: if (cnt != 6)
1.20 espie 286: err(1, "read failed (%zu/6)", cnt);
1.19 okan 287: break;
288: case SOCKS_IPV6:
289: cnt = atomicio(read, proxyfd, buf + 4, 18);
290: if (cnt != 18)
1.20 espie 291: err(1, "read failed (%zu/18)", cnt);
1.19 okan 292: break;
293: default:
294: errx(1, "connection failed, unsupported address type");
295: }
1.9 djm 296: } else if (socksv == 4) {
1.14 djm 297: /* This will exit on lookup failure */
298: decode_addrport(host, port, (struct sockaddr *)&addr,
299: sizeof(addr), 1, 0);
300:
1.5 markus 301: /* Version 4 */
302: buf[0] = SOCKS_V4;
303: buf[1] = SOCKS_CONNECT; /* connect */
1.14 djm 304: memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
305: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
1.5 markus 306: buf[8] = 0; /* empty username */
1.14 djm 307: wlen = 9;
1.5 markus 308:
1.15 avsm 309: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 310: if (cnt != wlen)
1.18 nicm 311: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 312:
1.14 djm 313: cnt = atomicio(read, proxyfd, buf, 8);
1.5 markus 314: if (cnt != 8)
1.18 nicm 315: err(1, "read failed (%zu/8)", cnt);
1.22 mmcc 316: if (buf[1] != 90) {
1.23 mmcc 317: errx(1, "connection failed, SOCKSv4 error: %s",
1.22 mmcc 318: socks4_strerror(buf[1]));
319: }
1.9 djm 320: } else if (socksv == -1) {
321: /* HTTP proxy CONNECT */
322:
323: /* Disallow bad chars in hostname */
324: if (strcspn(host, "\r\n\t []:") != strlen(host))
1.11 djm 325: errx(1, "Invalid hostname");
1.9 djm 326:
327: /* Try to be sane about numeric IPv6 addresses */
328: if (strchr(host, ':') != NULL) {
329: r = snprintf(buf, sizeof(buf),
1.16 djm 330: "CONNECT [%s]:%d HTTP/1.0\r\n",
1.9 djm 331: host, ntohs(serverport));
332: } else {
333: r = snprintf(buf, sizeof(buf),
1.16 djm 334: "CONNECT %s:%d HTTP/1.0\r\n",
1.9 djm 335: host, ntohs(serverport));
336: }
1.28 deraadt 337: if (r < 0 || (size_t)r >= sizeof(buf))
1.11 djm 338: errx(1, "hostname too long");
1.9 djm 339: r = strlen(buf);
340:
1.15 avsm 341: cnt = atomicio(vwrite, proxyfd, buf, r);
1.9 djm 342: if (cnt != r)
1.18 nicm 343: err(1, "write failed (%zu/%d)", cnt, r);
1.9 djm 344:
1.16 djm 345: if (authretry > 1) {
1.25 deraadt 346: char proxypass[256];
1.16 djm 347: char resp[1024];
348:
1.25 deraadt 349: getproxypass(proxyuser, proxyhost,
350: proxypass, sizeof proxypass);
1.16 djm 351: r = snprintf(buf, sizeof(buf), "%s:%s",
352: proxyuser, proxypass);
1.25 deraadt 353: explicit_bzero(proxypass, sizeof proxypass);
1.16 djm 354: if (r == -1 || (size_t)r >= sizeof(buf) ||
355: b64_ntop(buf, strlen(buf), resp,
356: sizeof(resp)) == -1)
357: errx(1, "Proxy username/password too long");
358: r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
359: "Basic %s\r\n", resp);
1.28 deraadt 360: if (r < 0 || (size_t)r >= sizeof(buf))
1.16 djm 361: errx(1, "Proxy auth response too long");
362: r = strlen(buf);
363: if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != r)
1.18 nicm 364: err(1, "write failed (%zu/%d)", cnt, r);
1.25 deraadt 365: explicit_bzero(proxypass, sizeof proxypass);
366: explicit_bzero(buf, sizeof buf);
1.16 djm 367: }
368:
369: /* Terminate headers */
1.21 tobias 370: if ((cnt = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
371: err(1, "write failed (%zu/2)", cnt);
1.16 djm 372:
373: /* Read status reply */
374: proxy_read_line(proxyfd, buf, sizeof(buf));
375: if (proxyuser != NULL &&
1.29 ! benno 376: (strncmp(buf, "HTTP/1.0 407 ", 12) == 0 ||
! 377: strncmp(buf, "HTTP/1.1 407 ", 12) == 0)) {
1.16 djm 378: if (authretry > 1) {
379: fprintf(stderr, "Proxy authentication "
380: "failed\n");
381: }
382: close(proxyfd);
383: goto again;
1.17 ray 384: } else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
385: strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
1.16 djm 386: errx(1, "Proxy error: \"%s\"", buf);
387:
388: /* Headers continue until we hit an empty line */
1.9 djm 389: for (r = 0; r < HTTP_MAXHDRS; r++) {
390: proxy_read_line(proxyfd, buf, sizeof(buf));
391: if (*buf == '\0')
392: break;
393: }
1.16 djm 394: if (*buf != '\0')
395: errx(1, "Too many proxy headers received");
1.9 djm 396: } else
1.11 djm 397: errx(1, "Unknown proxy protocol %d", socksv);
1.1 jakob 398:
1.11 djm 399: return (proxyfd);
1.1 jakob 400: }
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