Annotation of src/usr.bin/nc/socks.c, Revision 1.20
1.20 ! espie 1: /* $OpenBSD: socks.c,v 1.19 2011/02/12 15:54:18 okan 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:
1.1 jakob 125: int
1.10 otto 126: socks_connect(const char *host, const char *port,
127: struct addrinfo hints __attribute__ ((__unused__)),
128: const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
1.16 djm 129: int socksv, const char *proxyuser)
1.1 jakob 130: {
1.16 djm 131: int proxyfd, r, authretry = 0;
1.14 djm 132: size_t hlen, wlen;
1.9 djm 133: unsigned char buf[1024];
1.15 avsm 134: size_t cnt;
1.14 djm 135: struct sockaddr_storage addr;
136: struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
137: struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
1.1 jakob 138: in_port_t serverport;
1.16 djm 139: const char *proxypass = NULL;
1.1 jakob 140:
1.9 djm 141: if (proxyport == NULL)
142: proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
143:
1.14 djm 144: /* Abuse API to lookup port */
145: if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
146: sizeof(addr), 1, 1) == -1)
147: errx(1, "unknown port \"%.64s\"", port);
148: serverport = in4->sin_port;
1.1 jakob 149:
1.16 djm 150: again:
151: if (authretry++ > 3)
152: errx(1, "Too many authentication failures");
153:
154: proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
155:
156: if (proxyfd < 0)
157: return (-1);
158:
1.5 markus 159: if (socksv == 5) {
1.14 djm 160: if (decode_addrport(host, port, (struct sockaddr *)&addr,
161: sizeof(addr), 0, 1) == -1)
162: addr.ss_family = 0; /* used in switch below */
163:
1.5 markus 164: /* Version 5, one method: no authentication */
165: buf[0] = SOCKS_V5;
166: buf[1] = 1;
167: buf[2] = SOCKS_NOAUTH;
1.15 avsm 168: cnt = atomicio(vwrite, proxyfd, buf, 3);
1.5 markus 169: if (cnt != 3)
1.18 nicm 170: err(1, "write failed (%zu/3)", cnt);
1.15 avsm 171:
172: cnt = atomicio(read, proxyfd, buf, 2);
173: if (cnt != 2)
1.18 nicm 174: err(1, "read failed (%zu/3)", cnt);
1.5 markus 175:
176: if (buf[1] == SOCKS_NOMETHOD)
1.11 djm 177: errx(1, "authentication method negotiation failed");
1.5 markus 178:
1.14 djm 179: switch (addr.ss_family) {
180: case 0:
181: /* Version 5, connect: domain name */
182:
183: /* Max domain name length is 255 bytes */
184: hlen = strlen(host);
185: if (hlen > 255)
186: errx(1, "host name too long for SOCKS5");
187: buf[0] = SOCKS_V5;
188: buf[1] = SOCKS_CONNECT;
189: buf[2] = 0;
190: buf[3] = SOCKS_DOMAIN;
191: buf[4] = hlen;
192: memcpy(buf + 5, host, hlen);
193: memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
194: wlen = 7 + hlen;
195: break;
196: case AF_INET:
197: /* Version 5, connect: IPv4 address */
198: buf[0] = SOCKS_V5;
199: buf[1] = SOCKS_CONNECT;
200: buf[2] = 0;
201: buf[3] = SOCKS_IPV4;
202: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
203: memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
204: wlen = 10;
205: break;
206: case AF_INET6:
207: /* Version 5, connect: IPv6 address */
208: buf[0] = SOCKS_V5;
209: buf[1] = SOCKS_CONNECT;
210: buf[2] = 0;
211: buf[3] = SOCKS_IPV6;
212: memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
213: memcpy(buf + 20, &in6->sin6_port,
214: sizeof in6->sin6_port);
215: wlen = 22;
216: break;
217: default:
218: errx(1, "internal error: silly AF");
219: }
1.5 markus 220:
1.15 avsm 221: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 222: if (cnt != wlen)
1.18 nicm 223: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 224:
1.19 okan 225: cnt = atomicio(read, proxyfd, buf, 4);
226: if (cnt != 4)
227: err(1, "read failed (%zu/4)", cnt);
1.5 markus 228: if (buf[1] != 0)
1.11 djm 229: errx(1, "connection failed, SOCKS error %d", buf[1]);
1.19 okan 230: switch (buf[3]) {
231: case SOCKS_IPV4:
232: cnt = atomicio(read, proxyfd, buf + 4, 6);
233: if (cnt != 6)
1.20 ! espie 234: err(1, "read failed (%zu/6)", cnt);
1.19 okan 235: break;
236: case SOCKS_IPV6:
237: cnt = atomicio(read, proxyfd, buf + 4, 18);
238: if (cnt != 18)
1.20 ! espie 239: err(1, "read failed (%zu/18)", cnt);
1.19 okan 240: break;
241: default:
242: errx(1, "connection failed, unsupported address type");
243: }
1.9 djm 244: } else if (socksv == 4) {
1.14 djm 245: /* This will exit on lookup failure */
246: decode_addrport(host, port, (struct sockaddr *)&addr,
247: sizeof(addr), 1, 0);
248:
1.5 markus 249: /* Version 4 */
250: buf[0] = SOCKS_V4;
251: buf[1] = SOCKS_CONNECT; /* connect */
1.14 djm 252: memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
253: memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
1.5 markus 254: buf[8] = 0; /* empty username */
1.14 djm 255: wlen = 9;
1.5 markus 256:
1.15 avsm 257: cnt = atomicio(vwrite, proxyfd, buf, wlen);
1.14 djm 258: if (cnt != wlen)
1.18 nicm 259: err(1, "write failed (%zu/%zu)", cnt, wlen);
1.5 markus 260:
1.14 djm 261: cnt = atomicio(read, proxyfd, buf, 8);
1.5 markus 262: if (cnt != 8)
1.18 nicm 263: err(1, "read failed (%zu/8)", cnt);
1.5 markus 264: if (buf[1] != 90)
1.11 djm 265: errx(1, "connection failed, SOCKS error %d", buf[1]);
1.9 djm 266: } else if (socksv == -1) {
267: /* HTTP proxy CONNECT */
268:
269: /* Disallow bad chars in hostname */
270: if (strcspn(host, "\r\n\t []:") != strlen(host))
1.11 djm 271: errx(1, "Invalid hostname");
1.9 djm 272:
273: /* Try to be sane about numeric IPv6 addresses */
274: if (strchr(host, ':') != NULL) {
275: r = snprintf(buf, sizeof(buf),
1.16 djm 276: "CONNECT [%s]:%d HTTP/1.0\r\n",
1.9 djm 277: host, ntohs(serverport));
278: } else {
279: r = snprintf(buf, sizeof(buf),
1.16 djm 280: "CONNECT %s:%d HTTP/1.0\r\n",
1.9 djm 281: host, ntohs(serverport));
282: }
1.10 otto 283: if (r == -1 || (size_t)r >= sizeof(buf))
1.11 djm 284: errx(1, "hostname too long");
1.9 djm 285: r = strlen(buf);
286:
1.15 avsm 287: cnt = atomicio(vwrite, proxyfd, buf, r);
1.9 djm 288: if (cnt != r)
1.18 nicm 289: err(1, "write failed (%zu/%d)", cnt, r);
1.9 djm 290:
1.16 djm 291: if (authretry > 1) {
292: char resp[1024];
293:
294: proxypass = getproxypass(proxyuser, proxyhost);
295: r = snprintf(buf, sizeof(buf), "%s:%s",
296: proxyuser, proxypass);
297: if (r == -1 || (size_t)r >= sizeof(buf) ||
298: b64_ntop(buf, strlen(buf), resp,
299: sizeof(resp)) == -1)
300: errx(1, "Proxy username/password too long");
301: r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
302: "Basic %s\r\n", resp);
303: if (r == -1 || (size_t)r >= sizeof(buf))
304: errx(1, "Proxy auth response too long");
305: r = strlen(buf);
306: if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != r)
1.18 nicm 307: err(1, "write failed (%zu/%d)", cnt, r);
1.16 djm 308: }
309:
310: /* Terminate headers */
311: if ((r = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
312: err(1, "write failed (2/%d)", r);
313:
314: /* Read status reply */
315: proxy_read_line(proxyfd, buf, sizeof(buf));
316: if (proxyuser != NULL &&
317: strncmp(buf, "HTTP/1.0 407 ", 12) == 0) {
318: if (authretry > 1) {
319: fprintf(stderr, "Proxy authentication "
320: "failed\n");
321: }
322: close(proxyfd);
323: goto again;
1.17 ray 324: } else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
325: strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
1.16 djm 326: errx(1, "Proxy error: \"%s\"", buf);
327:
328: /* Headers continue until we hit an empty line */
1.9 djm 329: for (r = 0; r < HTTP_MAXHDRS; r++) {
330: proxy_read_line(proxyfd, buf, sizeof(buf));
331: if (*buf == '\0')
332: break;
333: }
1.16 djm 334: if (*buf != '\0')
335: errx(1, "Too many proxy headers received");
1.9 djm 336: } else
1.11 djm 337: errx(1, "Unknown proxy protocol %d", socksv);
1.1 jakob 338:
1.11 djm 339: return (proxyfd);
1.1 jakob 340: }
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