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186463e7fa
curl/lib/socks.c
Daniel Stenberg d44896508c Curl_SOCKS4: minor code compression
2011-08-18 23:28:50 +02:00

719 lines
22 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "setup.h"
#if !defined(CURL_DISABLE_PROXY) || defined(USE_WINDOWS_SSPI)
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include "urldata.h"
#include "sendf.h"
#include "strequal.h"
#include "select.h"
#include "connect.h"
#include "timeval.h"
#include "socks.h"
/* The last #include file should be: */
#include "memdebug.h"
/*
* Helper read-from-socket functions. Does the same as Curl_read() but it
* blocks until all bytes amount of buffersize will be read. No more, no less.
*
* This is STUPID BLOCKING behaviour which we frown upon, but right now this
* is what we have...
*/
int Curl_blockread_all(struct connectdata *conn, /* connection data */
curl_socket_t sockfd, /* read from this socket */
char *buf, /* store read data here */
ssize_t buffersize, /* max amount to read */
ssize_t *n) /* amount bytes read */
{
ssize_t nread;
ssize_t allread = 0;
int result;
long timeleft;
*n = 0;
for(;;) {
timeleft = Curl_timeleft(conn->data, NULL, TRUE);
if(timeleft < 0) {
/* we already got the timeout */
result = CURLE_OPERATION_TIMEDOUT;
break;
}
if(Curl_socket_ready(sockfd, CURL_SOCKET_BAD, timeleft) <= 0) {
result = ~CURLE_OK;
break;
}
result = Curl_read_plain(sockfd, buf, buffersize, &nread);
if(CURLE_AGAIN == result)
continue;
else if(result)
break;
if(buffersize == nread) {
allread += nread;
*n = allread;
result = CURLE_OK;
break;
}
if(!nread) {
result = ~CURLE_OK;
break;
}
buffersize -= nread;
buf += nread;
allread += nread;
}
return result;
}
/*
* This function logs in to a SOCKS4 proxy and sends the specifics to the final
* destination server.
*
* Reference :
* http://socks.permeo.com/protocol/socks4.protocol
*
* Note :
* Set protocol4a=true for "SOCKS 4A (Simple Extension to SOCKS 4 Protocol)"
* Nonsupport "Identification Protocol (RFC1413)"
*/
CURLcode Curl_SOCKS4(const char *proxy_name,
const char *hostname,
int remote_port,
int sockindex,
struct connectdata *conn,
bool protocol4a)
{
#define SOCKS4REQLEN 262
unsigned char socksreq[SOCKS4REQLEN]; /* room for SOCKS4 request incl. user
id */
int result;
CURLcode code;
curl_socket_t sock = conn->sock[sockindex];
struct SessionHandle *data = conn->data;
if(Curl_timeleft(data, NULL, TRUE) < 0) {
/* time-out, bail out, go home */
failf(data, "Connection time-out");
return CURLE_OPERATION_TIMEDOUT;
}
curlx_nonblock(sock, FALSE);
/*
* Compose socks4 request
*
* Request format
*
* +----+----+----+----+----+----+----+----+----+----+....+----+
* | VN | CD | DSTPORT | DSTIP | USERID |NULL|
* +----+----+----+----+----+----+----+----+----+----+....+----+
* # of bytes: 1 1 2 4 variable 1
*/
socksreq[0] = 4; /* version (SOCKS4) */
socksreq[1] = 1; /* connect */
socksreq[2] = (unsigned char)((remote_port >> 8) & 0xff); /* PORT MSB */
socksreq[3] = (unsigned char)(remote_port & 0xff); /* PORT LSB */
/* DNS resolve only for SOCKS4, not SOCKS4a */
if(!protocol4a) {
struct Curl_dns_entry *dns;
Curl_addrinfo *hp=NULL;
int rc;
rc = Curl_resolv(conn, hostname, remote_port, &dns);
if(rc == CURLRESOLV_ERROR)
return CURLE_COULDNT_RESOLVE_PROXY;
if(rc == CURLRESOLV_PENDING)
/* ignores the return code, but 'dns' remains NULL on failure */
(void)Curl_resolver_wait_resolv(conn, &dns);
/*
* We cannot use 'hostent' as a struct that Curl_resolv() returns. It
* returns a Curl_addrinfo pointer that may not always look the same.
*/
if(dns)
hp=dns->addr;
if(hp) {
char buf[64];
unsigned short ip[4];
Curl_printable_address(hp, buf, sizeof(buf));
if(4 == sscanf( buf, "%hu.%hu.%hu.%hu",
&ip[0], &ip[1], &ip[2], &ip[3])) {
/* Set DSTIP */
socksreq[4] = (unsigned char)ip[0];
socksreq[5] = (unsigned char)ip[1];
socksreq[6] = (unsigned char)ip[2];
socksreq[7] = (unsigned char)ip[3];
}
else
hp = NULL; /* fail! */
Curl_resolv_unlock(data, dns); /* not used anymore from now on */
}
if(!hp) {
failf(data, "Failed to resolve \"%s\" for SOCKS4 connect.",
hostname);
return CURLE_COULDNT_RESOLVE_HOST;
}
}
/*
* This is currently not supporting "Identification Protocol (RFC1413)".
*/
socksreq[8] = 0; /* ensure empty userid is NUL-terminated */
if(proxy_name)
strlcat((char*)socksreq + 8, proxy_name, sizeof(socksreq) - 8);
/*
* Make connection
*/
{
ssize_t actualread;
ssize_t written;
ssize_t hostnamelen = 0;
int packetsize = 9 +
(int)strlen((char*)socksreq + 8); /* size including NUL */
/* If SOCKS4a, set special invalid IP address 0.0.0.x */
if(protocol4a) {
socksreq[4] = 0;
socksreq[5] = 0;
socksreq[6] = 0;
socksreq[7] = 1;
/* If still enough room in buffer, also append hostname */
hostnamelen = (ssize_t)strlen(hostname) + 1; /* length including NUL */
if(packetsize + hostnamelen <= SOCKS4REQLEN)
strcpy((char*)socksreq + packetsize, hostname);
else
hostnamelen = 0; /* Flag: hostname did not fit in buffer */
}
/* Send request */
code = Curl_write_plain(conn, sock, (char *)socksreq,
packetsize + hostnamelen,
&written);
if((code != CURLE_OK) || (written != packetsize + hostnamelen)) {
failf(data, "Failed to send SOCKS4 connect request.");
return CURLE_COULDNT_CONNECT;
}
if(protocol4a && hostnamelen == 0) {
/* SOCKS4a with very long hostname - send that name separately */
hostnamelen = (ssize_t)strlen(hostname) + 1;
code = Curl_write_plain(conn, sock, (char *)hostname, hostnamelen,
&written);
if((code != CURLE_OK) || (written != hostnamelen)) {
failf(data, "Failed to send SOCKS4 connect request.");
return CURLE_COULDNT_CONNECT;
}
}
packetsize = 8; /* receive data size */
/* Receive response */
result = Curl_blockread_all(conn, sock, (char *)socksreq, packetsize,
&actualread);
if((result != CURLE_OK) || (actualread != packetsize)) {
failf(data, "Failed to receive SOCKS4 connect request ack.");
return CURLE_COULDNT_CONNECT;
}
/*
* Response format
*
* +----+----+----+----+----+----+----+----+
* | VN | CD | DSTPORT | DSTIP |
* +----+----+----+----+----+----+----+----+
* # of bytes: 1 1 2 4
*
* VN is the version of the reply code and should be 0. CD is the result
* code with one of the following values:
*
* 90: request granted
* 91: request rejected or failed
* 92: request rejected because SOCKS server cannot connect to
* identd on the client
* 93: request rejected because the client program and identd
* report different user-ids
*/
/* wrong version ? */
if(socksreq[0] != 0) {
failf(data,
"SOCKS4 reply has wrong version, version should be 4.");
return CURLE_COULDNT_CONNECT;
}
/* Result */
switch(socksreq[1]) {
case 90:
infof(data, "SOCKS4%s request granted.\n", protocol4a?"a":"");
break;
case 91:
failf(data,
"Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
", request rejected or failed.",
(unsigned char)socksreq[4], (unsigned char)socksreq[5],
(unsigned char)socksreq[6], (unsigned char)socksreq[7],
((socksreq[8] << 8) | socksreq[9]),
socksreq[1]);
return CURLE_COULDNT_CONNECT;
case 92:
failf(data,
"Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
", request rejected because SOCKS server cannot connect to "
"identd on the client.",
(unsigned char)socksreq[4], (unsigned char)socksreq[5],
(unsigned char)socksreq[6], (unsigned char)socksreq[7],
((socksreq[8] << 8) | socksreq[9]),
socksreq[1]);
return CURLE_COULDNT_CONNECT;
case 93:
failf(data,
"Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
", request rejected because the client program and identd "
"report different user-ids.",
(unsigned char)socksreq[4], (unsigned char)socksreq[5],
(unsigned char)socksreq[6], (unsigned char)socksreq[7],
((socksreq[8] << 8) | socksreq[9]),
socksreq[1]);
return CURLE_COULDNT_CONNECT;
default:
failf(data,
"Can't complete SOCKS4 connection to %d.%d.%d.%d:%d. (%d)"
", Unknown.",
(unsigned char)socksreq[4], (unsigned char)socksreq[5],
(unsigned char)socksreq[6], (unsigned char)socksreq[7],
((socksreq[8] << 8) | socksreq[9]),
socksreq[1]);
return CURLE_COULDNT_CONNECT;
}
}
curlx_nonblock(sock, TRUE);
return CURLE_OK; /* Proxy was successful! */
}
/*
* This function logs in to a SOCKS5 proxy and sends the specifics to the final
* destination server.
*/
CURLcode Curl_SOCKS5(const char *proxy_name,
const char *proxy_password,
const char *hostname,
int remote_port,
int sockindex,
struct connectdata *conn)
{
/*
According to the RFC1928, section "6. Replies". This is what a SOCK5
replies:
+----+-----+-------+------+----------+----------+
|VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
+----+-----+-------+------+----------+----------+
| 1 | 1 | X'00' | 1 | Variable | 2 |
+----+-----+-------+------+----------+----------+
Where:
o VER protocol version: X'05'
o REP Reply field:
o X'00' succeeded
*/
unsigned char socksreq[600]; /* room for large user/pw (255 max each) */
ssize_t actualread;
ssize_t written;
int result;
CURLcode code;
curl_socket_t sock = conn->sock[sockindex];
struct SessionHandle *data = conn->data;
long timeout;
bool socks5_resolve_local = (bool)(conn->proxytype == CURLPROXY_SOCKS5);
const size_t hostname_len = strlen(hostname);
ssize_t packetsize = 0;
/* RFC1928 chapter 5 specifies max 255 chars for domain name in packet */
if(!socks5_resolve_local && hostname_len > 255) {
infof(conn->data,"SOCKS5: server resolving disabled for hostnames of "
"length > 255 [actual len=%zu]\n", hostname_len);
socks5_resolve_local = TRUE;
}
/* get timeout */
timeout = Curl_timeleft(data, NULL, TRUE);
if(timeout < 0) {
/* time-out, bail out, go home */
failf(data, "Connection time-out");
return CURLE_OPERATION_TIMEDOUT;
}
curlx_nonblock(sock, TRUE);
/* wait until socket gets connected */
result = Curl_socket_ready(CURL_SOCKET_BAD, sock, timeout);
if(-1 == result) {
failf(conn->data, "SOCKS5: no connection here");
return CURLE_COULDNT_CONNECT;
}
else if(0 == result) {
failf(conn->data, "SOCKS5: connection timeout");
return CURLE_OPERATION_TIMEDOUT;
}
if(result & CURL_CSELECT_ERR) {
failf(conn->data, "SOCKS5: error occurred during connection");
return CURLE_COULDNT_CONNECT;
}
socksreq[0] = 5; /* version */
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
socksreq[1] = (char)(proxy_name ? 3 : 2); /* number of methods (below) */
socksreq[2] = 0; /* no authentication */
socksreq[3] = 1; /* gssapi */
socksreq[4] = 2; /* username/password */
#else
socksreq[1] = (char)(proxy_name ? 2 : 1); /* number of methods (below) */
socksreq[2] = 0; /* no authentication */
socksreq[3] = 2; /* username/password */
#endif
curlx_nonblock(sock, FALSE);
code = Curl_write_plain(conn, sock, (char *)socksreq, (2 + (int)socksreq[1]),
&written);
if((code != CURLE_OK) || (written != (2 + (int)socksreq[1]))) {
failf(data, "Unable to send initial SOCKS5 request.");
return CURLE_COULDNT_CONNECT;
}
curlx_nonblock(sock, TRUE);
result = Curl_socket_ready(sock, CURL_SOCKET_BAD, timeout);
if(-1 == result) {
failf(conn->data, "SOCKS5 nothing to read");
return CURLE_COULDNT_CONNECT;
}
else if(0 == result) {
failf(conn->data, "SOCKS5 read timeout");
return CURLE_OPERATION_TIMEDOUT;
}
if(result & CURL_CSELECT_ERR) {
failf(conn->data, "SOCKS5 read error occurred");
return CURLE_RECV_ERROR;
}
curlx_nonblock(sock, FALSE);
result=Curl_blockread_all(conn, sock, (char *)socksreq, 2, &actualread);
if((result != CURLE_OK) || (actualread != 2)) {
failf(data, "Unable to receive initial SOCKS5 response.");
return CURLE_COULDNT_CONNECT;
}
if(socksreq[0] != 5) {
failf(data, "Received invalid version in initial SOCKS5 response.");
return CURLE_COULDNT_CONNECT;
}
if(socksreq[1] == 0) {
/* Nothing to do, no authentication needed */
;
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
else if(socksreq[1] == 1) {
code = Curl_SOCKS5_gssapi_negotiate(sockindex, conn);
if(code != CURLE_OK) {
failf(data, "Unable to negotiate SOCKS5 gssapi context.");
return CURLE_COULDNT_CONNECT;
}
}
#endif
else if(socksreq[1] == 2) {
/* Needs user name and password */
size_t userlen, pwlen;
int len;
if(proxy_name && proxy_password) {
userlen = strlen(proxy_name);
pwlen = strlen(proxy_password);
}
else {
userlen = 0;
pwlen = 0;
}
/* username/password request looks like
* +----+------+----------+------+----------+
* |VER | ULEN | UNAME | PLEN | PASSWD |
* +----+------+----------+------+----------+
* | 1 | 1 | 1 to 255 | 1 | 1 to 255 |
* +----+------+----------+------+----------+
*/
len = 0;
socksreq[len++] = 1; /* username/pw subnegotiation version */
socksreq[len++] = (unsigned char) userlen;
if(proxy_name && userlen)
memcpy(socksreq + len, proxy_name, userlen);
len += (int)userlen;
socksreq[len++] = (unsigned char) pwlen;
if(proxy_password && pwlen)
memcpy(socksreq + len, proxy_password, pwlen);
len += (int)pwlen;
code = Curl_write_plain(conn, sock, (char *)socksreq, len, &written);
if((code != CURLE_OK) || (len != written)) {
failf(data, "Failed to send SOCKS5 sub-negotiation request.");
return CURLE_COULDNT_CONNECT;
}
result=Curl_blockread_all(conn, sock, (char *)socksreq, 2, &actualread);
if((result != CURLE_OK) || (actualread != 2)) {
failf(data, "Unable to receive SOCKS5 sub-negotiation response.");
return CURLE_COULDNT_CONNECT;
}
/* ignore the first (VER) byte */
if(socksreq[1] != 0) { /* status */
failf(data, "User was rejected by the SOCKS5 server (%d %d).",
socksreq[0], socksreq[1]);
return CURLE_COULDNT_CONNECT;
}
/* Everything is good so far, user was authenticated! */
}
else {
/* error */
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(socksreq[1] == 255) {
#else
if(socksreq[1] == 1) {
failf(data,
"SOCKS5 GSSAPI per-message authentication is not supported.");
return CURLE_COULDNT_CONNECT;
}
else if(socksreq[1] == 255) {
#endif
if(!proxy_name || !*proxy_name) {
failf(data,
"No authentication method was acceptable. (It is quite likely"
" that the SOCKS5 server wanted a username/password, since none"
" was supplied to the server on this connection.)");
}
else {
failf(data, "No authentication method was acceptable.");
}
return CURLE_COULDNT_CONNECT;
}
else {
failf(data,
"Undocumented SOCKS5 mode attempted to be used by server.");
return CURLE_COULDNT_CONNECT;
}
}
/* Authentication is complete, now specify destination to the proxy */
socksreq[0] = 5; /* version (SOCKS5) */
socksreq[1] = 1; /* connect */
socksreq[2] = 0; /* must be zero */
if(!socks5_resolve_local) {
packetsize = (ssize_t)(5 + hostname_len + 2);
socksreq[3] = 3; /* ATYP: domain name = 3 */
socksreq[4] = (char) hostname_len; /* address length */
memcpy(&socksreq[5], hostname, hostname_len); /* address bytes w/o NULL */
/* PORT MSB */
socksreq[hostname_len+5] = (unsigned char)((remote_port >> 8) & 0xff);
/* PORT LSB */
socksreq[hostname_len+6] = (unsigned char)(remote_port & 0xff);
}
else {
struct Curl_dns_entry *dns;
Curl_addrinfo *hp=NULL;
int rc = Curl_resolv(conn, hostname, remote_port, &dns);
packetsize = 10;
socksreq[3] = 1; /* IPv4 = 1 */
if(rc == CURLRESOLV_ERROR)
return CURLE_COULDNT_RESOLVE_HOST;
if(rc == CURLRESOLV_PENDING) {
/* this requires that we're in "wait for resolve" state */
code = Curl_resolver_wait_resolv(conn, &dns);
if(code != CURLE_OK)
return code;
}
/*
* We cannot use 'hostent' as a struct that Curl_resolv() returns. It
* returns a Curl_addrinfo pointer that may not always look the same.
*/
if(dns)
hp=dns->addr;
if(hp) {
char buf[64];
unsigned short ip[4];
Curl_printable_address(hp, buf, sizeof(buf));
if(4 == sscanf( buf, "%hu.%hu.%hu.%hu",
&ip[0], &ip[1], &ip[2], &ip[3])) {
socksreq[4] = (unsigned char)ip[0];
socksreq[5] = (unsigned char)ip[1];
socksreq[6] = (unsigned char)ip[2];
socksreq[7] = (unsigned char)ip[3];
}
else
hp = NULL; /* fail! */
Curl_resolv_unlock(data, dns); /* not used anymore from now on */
}
if(!hp) {
failf(data, "Failed to resolve \"%s\" for SOCKS5 connect.",
hostname);
return CURLE_COULDNT_RESOLVE_HOST;
}
socksreq[8] = (unsigned char)((remote_port >> 8) & 0xff); /* PORT MSB */
socksreq[9] = (unsigned char)(remote_port & 0xff); /* PORT LSB */
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(conn->socks5_gssapi_enctype) {
failf(data, "SOCKS5 gssapi protection not yet implemented.");
}
else
#endif
code = Curl_write_plain(conn, sock, (char *)socksreq, packetsize,
&written);
if((code != CURLE_OK) || (written != packetsize)) {
failf(data, "Failed to send SOCKS5 connect request.");
return CURLE_COULDNT_CONNECT;
}
packetsize = 10; /* minimum packet size is 10 */
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(conn->socks5_gssapi_enctype) {
failf(data, "SOCKS5 gssapi protection not yet implemented.");
}
else
#endif
result = Curl_blockread_all(conn, sock, (char *)socksreq, packetsize,
&actualread);
if((result != CURLE_OK) || (actualread != packetsize)) {
failf(data, "Failed to receive SOCKS5 connect request ack.");
return CURLE_COULDNT_CONNECT;
}
if(socksreq[0] != 5) { /* version */
failf(data,
"SOCKS5 reply has wrong version, version should be 5.");
return CURLE_COULDNT_CONNECT;
}
if(socksreq[1] != 0) { /* Anything besides 0 is an error */
failf(data,
"Can't complete SOCKS5 connection to %d.%d.%d.%d:%d. (%d)",
(unsigned char)socksreq[4], (unsigned char)socksreq[5],
(unsigned char)socksreq[6], (unsigned char)socksreq[7],
((socksreq[8] << 8) | socksreq[9]),
socksreq[1]);
return CURLE_COULDNT_CONNECT;
}
/* Fix: in general, returned BND.ADDR is variable length parameter by RFC
1928, so the reply packet should be read until the end to avoid errors at
subsequent protocol level.
+----+-----+-------+------+----------+----------+
|VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
+----+-----+-------+------+----------+----------+
| 1 | 1 | X'00' | 1 | Variable | 2 |
+----+-----+-------+------+----------+----------+
ATYP:
o IP v4 address: X'01', BND.ADDR = 4 byte
o domain name: X'03', BND.ADDR = [ 1 byte length, string ]
o IP v6 address: X'04', BND.ADDR = 16 byte
*/
/* Calculate real packet size */
if(socksreq[3] == 3) {
/* domain name */
int addrlen = (int) socksreq[4];
packetsize = 5 + addrlen + 2;
}
else if(socksreq[3] == 4) {
/* IPv6 */
packetsize = 4 + 16 + 2;
}
/* At this point we already read first 10 bytes */
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(!conn->socks5_gssapi_enctype) {
/* decrypt_gssapi_blockread already read the whole packet */
#endif
if(packetsize > 10) {
packetsize -= 10;
result = Curl_blockread_all(conn, sock, (char *)&socksreq[10],
packetsize, &actualread);
if((result != CURLE_OK) || (actualread != packetsize)) {
failf(data, "Failed to receive SOCKS5 connect request ack.");
return CURLE_COULDNT_CONNECT;
}
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
}
#endif
curlx_nonblock(sock, TRUE);
return CURLE_OK; /* Proxy was successful! */
}
#endif /* CURL_DISABLE_PROXY */
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