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Code Issues Releases Wiki Activity
c79e428940
curl/lib/socks.c
Daniel Stenberg f0e8160545
socks4: fix host resolve regression 
1. The socks4 state machine was broken in the host resolving phase

2. The code now insists on IPv4-only when using SOCKS4 as the protocol
only supports that.

Regression from #4907 and 4a4b63d, shipped in 7.69.0

Reported-by: amishmm on github
Bug: https://github.com/curl/curl/issues/5053#issuecomment-596191594
Closes #5061
2020-03-08 22:51:47 +01:00

980 lines
30 KiB
C
Raw Blame History

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, 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 https://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 "curl_setup.h"
#if !defined(CURL_DISABLE_PROXY)
#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 "select.h"
#include "connect.h"
#include "timeval.h"
#include "socks.h"
#include "multiif.h" /* for getsock macros */
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
/*
* 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 behavior. Only used by the SOCKS GSSAPI functions.
*/
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 = 0;
ssize_t allread = 0;
int result;
*n = 0;
for(;;) {
timediff_t timeleft = Curl_timeleft(conn->data, NULL, TRUE);
if(timeleft < 0) {
/* we already got the timeout */
result = CURLE_OPERATION_TIMEDOUT;
break;
}
if(SOCKET_READABLE(sockfd, timeleft) <= 0) {
result = ~CURLE_OK;
break;
}
result = Curl_read_plain(sockfd, buf, buffersize, &nread);
if(CURLE_AGAIN == result)
continue;
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;
}
#endif
#ifndef DEBUGBUILD
#define sxstate(x,y) socksstate(x,y)
#else
#define sxstate(x,y) socksstate(x,y, __LINE__)
#endif
/* always use this function to change state, to make debugging easier */
static void socksstate(struct connectdata *conn,
enum connect_t state
#ifdef DEBUGBUILD
, int lineno
#endif
)
{
enum connect_t oldstate = conn->cnnct.state;
#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
/* synced with the state list in urldata.h */
static const char * const statename[] = {
"INIT",
"SOCKS_INIT",
"SOCKS_SEND",
"SOCKS_READ_INIT",
"SOCKS_READ",
"GSSAPI_INIT",
"AUTH_INIT",
"AUTH_SEND",
"AUTH_READ",
"REQ_INIT",
"RESOLVING",
"RESOLVED",
"RESOLVE_REMOTE",
"REQ_SEND",
"REQ_SENDING",
"REQ_READ",
"REQ_READ_MORE",
"DONE"
};
#endif
if(oldstate == state)
/* don't bother when the new state is the same as the old state */
return;
conn->cnnct.state = state;
#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
infof(conn->data,
"SXSTATE: %s => %s conn %p; line %d\n",
statename[oldstate], statename[conn->cnnct.state], conn,
lineno);
#endif
}
int Curl_SOCKS_getsock(struct connectdata *conn, curl_socket_t *sock,
int sockindex)
{
int rc = 0;
sock[0] = conn->sock[sockindex];
switch(conn->cnnct.state) {
case CONNECT_RESOLVING:
case CONNECT_SOCKS_READ:
case CONNECT_AUTH_READ:
case CONNECT_REQ_READ:
case CONNECT_REQ_READ_MORE:
rc = GETSOCK_READSOCK(0);
break;
default:
rc = GETSOCK_WRITESOCK(0);
break;
}
return rc;
}
/*
* This function logs in to a SOCKS4 proxy and sends the specifics to the final
* destination server.
*
* Reference :
* https://www.openssh.com/txt/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_user,
const char *hostname,
int remote_port,
int sockindex,
struct connectdata *conn,
bool *done)
{
const bool protocol4a =
(conn->socks_proxy.proxytype == CURLPROXY_SOCKS4A) ? TRUE : FALSE;
unsigned char *socksreq = &conn->cnnct.socksreq[0];
CURLcode result;
curl_socket_t sockfd = conn->sock[sockindex];
struct Curl_easy *data = conn->data;
struct connstate *sx = &conn->cnnct;
struct Curl_dns_entry *dns = NULL;
ssize_t actualread;
ssize_t written;
if(!SOCKS_STATE(sx->state) && !*done)
sxstate(conn, CONNECT_SOCKS_INIT);
switch(sx->state) {
case CONNECT_SOCKS_INIT:
/* SOCKS4 can only do IPv4, insist! */
conn->ip_version = CURL_IPRESOLVE_V4;
if(conn->bits.httpproxy)
infof(conn->data, "SOCKS4%s: connecting to HTTP proxy %s port %d\n",
protocol4a ? "a" : "", hostname, remote_port);
infof(data, "SOCKS4 communication to %s:%d\n", hostname, remote_port);
/*
* 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) {
enum resolve_t rc =
Curl_resolv(conn, hostname, remote_port, FALSE, &dns);
if(rc == CURLRESOLV_ERROR)
return CURLE_COULDNT_RESOLVE_PROXY;
else if(rc == CURLRESOLV_PENDING) {
sxstate(conn, CONNECT_RESOLVING);
infof(data, "SOCKS4 non-blocking resolve of %s\n", hostname);
return CURLE_OK;
}
sxstate(conn, CONNECT_RESOLVED);
goto CONNECT_RESOLVED;
}
/* socks4a doesn't resolve anything locally */
sxstate(conn, CONNECT_REQ_INIT);
goto CONNECT_REQ_INIT;
case CONNECT_RESOLVING:
/* check if we have the name resolved by now */
dns = Curl_fetch_addr(conn, hostname, (int)conn->port);
if(dns) {
#ifdef CURLRES_ASYNCH
conn->async.dns = dns;
conn->async.done = TRUE;
#endif
infof(data, "Hostname '%s' was found\n", hostname);
sxstate(conn, CONNECT_RESOLVED);
}
else {
result = Curl_resolv_check(data->conn, &dns);
if(!dns)
return result;
}
/* FALLTHROUGH */
CONNECT_RESOLVED:
case CONNECT_RESOLVED: {
Curl_addrinfo *hp = NULL;
char buf[64];
/*
* 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) {
Curl_printable_address(hp, buf, sizeof(buf));
if(hp->ai_family == AF_INET) {
struct sockaddr_in *saddr_in;
saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
socksreq[4] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[0];
socksreq[5] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[1];
socksreq[6] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[2];
socksreq[7] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[3];
infof(data, "SOCKS4 connect to IPv4 %s (locally resolved)\n", buf);
}
else {
hp = NULL; /* fail! */
failf(data, "SOCKS4 connection to %s not supported\n", buf);
}
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;
}
}
/* FALLTHROUGH */
CONNECT_REQ_INIT:
case CONNECT_REQ_INIT:
/*
* This is currently not supporting "Identification Protocol (RFC1413)".
*/
socksreq[8] = 0; /* ensure empty userid is NUL-terminated */
if(proxy_user) {
size_t plen = strlen(proxy_user);
if(plen >= sizeof(sx->socksreq) - 8) {
failf(data, "Too long SOCKS proxy name, can't use!\n");
return CURLE_COULDNT_CONNECT;
}
/* copy the proxy name WITH trailing zero */
memcpy(socksreq + 8, proxy_user, plen + 1);
}
/*
* Make connection
*/
{
ssize_t packetsize = 9 +
strlen((char *)socksreq + 8); /* size including NUL */
/* If SOCKS4a, set special invalid IP address 0.0.0.x */
if(protocol4a) {
ssize_t hostnamelen = 0;
socksreq[4] = 0;
socksreq[5] = 0;
socksreq[6] = 0;
socksreq[7] = 1;
/* append hostname */
hostnamelen = (ssize_t)strlen(hostname) + 1; /* length including NUL */
if(hostnamelen <= 255)
strcpy((char *)socksreq + packetsize, hostname);
else {
failf(data, "SOCKS4: too long host name");
return CURLE_COULDNT_CONNECT;
}
packetsize += hostnamelen;
}
sx->outp = socksreq;
sx->outstanding = packetsize;
sxstate(conn, CONNECT_REQ_SENDING);
}
/* FALLTHROUGH */
case CONNECT_REQ_SENDING:
/* Send request */
result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
sx->outstanding, &written);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Failed to send SOCKS4 connect request.");
return CURLE_COULDNT_CONNECT;
}
if(written != sx->outstanding) {
/* not done, remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLE_OK;
}
/* done sending! */
sx->outstanding = 8; /* receive data size */
sx->outp = socksreq;
sxstate(conn, CONNECT_SOCKS_READ);
/* FALLTHROUGH */
case CONNECT_SOCKS_READ:
/* Receive response */
result = Curl_read_plain(sockfd, (char *)sx->outp,
sx->outstanding, &actualread);
if(result && (CURLE_AGAIN != result)) {
failf(data, "SOCKS4: Failed receiving connect request ack: %s",
curl_easy_strerror(result));
return CURLE_COULDNT_CONNECT;
}
else if(actualread != sx->outstanding) {
/* remain in reading state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLE_OK;
}
sxstate(conn, CONNECT_DONE);
break;
default: /* lots of unused states in SOCKS4 */
break;
}
/*
* 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 0.");
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],
(((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
(unsigned char)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],
(((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
(unsigned char)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],
(((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
(unsigned char)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],
(((unsigned char)socksreq[2] << 8) | (unsigned char)socksreq[3]),
(unsigned char)socksreq[1]);
return CURLE_COULDNT_CONNECT;
}
*done = 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_user,
const char *proxy_password,
const char *hostname,
int remote_port,
int sockindex,
struct connectdata *conn,
bool *done)
{
/*
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 = &conn->cnnct.socksreq[0];
char dest[256] = "unknown"; /* printable hostname:port */
int idx;
ssize_t actualread;
ssize_t written;
CURLcode result;
curl_socket_t sockfd = conn->sock[sockindex];
struct Curl_easy *data = conn->data;
bool socks5_resolve_local =
(conn->socks_proxy.proxytype == CURLPROXY_SOCKS5) ? TRUE : FALSE;
const size_t hostname_len = strlen(hostname);
ssize_t len = 0;
const unsigned long auth = data->set.socks5auth;
bool allow_gssapi = FALSE;
struct connstate *sx = &conn->cnnct;
struct Curl_dns_entry *dns = NULL;
if(!SOCKS_STATE(sx->state) && !*done)
sxstate(conn, CONNECT_SOCKS_INIT);
switch(sx->state) {
case CONNECT_SOCKS_INIT:
if(conn->bits.httpproxy)
infof(conn->data, "SOCKS5: connecting to HTTP proxy %s port %d\n",
hostname, remote_port);
/* 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;
}
if(auth & ~(CURLAUTH_BASIC | CURLAUTH_GSSAPI))
infof(conn->data,
"warning: unsupported value passed to CURLOPT_SOCKS5_AUTH: %lu\n",
auth);
if(!(auth & CURLAUTH_BASIC))
/* disable username/password auth */
proxy_user = NULL;
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(auth & CURLAUTH_GSSAPI)
allow_gssapi = TRUE;
#endif
idx = 0;
socksreq[idx++] = 5; /* version */
idx++; /* number of authentication methods */
socksreq[idx++] = 0; /* no authentication */
if(allow_gssapi)
socksreq[idx++] = 1; /* GSS-API */
if(proxy_user)
socksreq[idx++] = 2; /* username/password */
/* write the number of authentication methods */
socksreq[1] = (unsigned char) (idx - 2);
result = Curl_write_plain(conn, sockfd, (char *)socksreq, idx, &written);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Unable to send initial SOCKS5 request.");
return CURLE_COULDNT_CONNECT;
}
if(written != idx) {
sxstate(conn, CONNECT_SOCKS_SEND);
sx->outstanding = idx - written;
sx->outp = &socksreq[written];
return CURLE_OK;
}
sxstate(conn, CONNECT_SOCKS_READ);
goto CONNECT_SOCKS_READ_INIT;
case CONNECT_SOCKS_SEND:
result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
sx->outstanding, &written);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Unable to send initial SOCKS5 request.");
return CURLE_COULDNT_CONNECT;
}
if(written != sx->outstanding) {
/* not done, remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLE_OK;
}
/* FALLTHROUGH */
CONNECT_SOCKS_READ_INIT:
case CONNECT_SOCKS_READ_INIT:
sx->outstanding = 2; /* expect two bytes */
sx->outp = socksreq; /* store it here */
/* FALLTHROUGH */
case CONNECT_SOCKS_READ:
result = Curl_read_plain(sockfd, (char *)sx->outp,
sx->outstanding, &actualread);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Unable to receive initial SOCKS5 response.");
return CURLE_COULDNT_CONNECT;
}
else if(actualread != sx->outstanding) {
/* remain in reading state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLE_OK;
}
else if(socksreq[0] != 5) {
failf(data, "Received invalid version in initial SOCKS5 response.");
return CURLE_COULDNT_CONNECT;
}
else if(socksreq[1] == 0) {
/* DONE! No authentication needed. Send request. */
sxstate(conn, CONNECT_REQ_INIT);
goto CONNECT_REQ_INIT;
}
else if(socksreq[1] == 2) {
/* regular name + password authentication */
sxstate(conn, CONNECT_AUTH_INIT);
goto CONNECT_AUTH_INIT;
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
else if(allow_gssapi && (socksreq[1] == 1)) {
sxstate(conn, CONNECT_GSSAPI_INIT);
result = Curl_SOCKS5_gssapi_negotiate(sockindex, conn);
if(result) {
failf(data, "Unable to negotiate SOCKS5 GSS-API context.");
return CURLE_COULDNT_CONNECT;
}
}
#endif
else {
/* error */
if(!allow_gssapi && (socksreq[1] == 1)) {
failf(data,
"SOCKS5 GSSAPI per-message authentication is not supported.");
return CURLE_COULDNT_CONNECT;
}
else if(socksreq[1] == 255) {
failf(data, "No authentication method was acceptable.");
return CURLE_COULDNT_CONNECT;
}
failf(data,
"Undocumented SOCKS5 mode attempted to be used by server.");
return CURLE_COULDNT_CONNECT;
}
break;
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
case CONNECT_GSSAPI_INIT:
/* GSSAPI stuff done non-blocking */
break;
#endif
default: /* do nothing! */
break;
CONNECT_AUTH_INIT:
case CONNECT_AUTH_INIT: {
/* Needs user name and password */
size_t proxy_user_len, proxy_password_len;
if(proxy_user && proxy_password) {
proxy_user_len = strlen(proxy_user);
proxy_password_len = strlen(proxy_password);
}
else {
proxy_user_len = 0;
proxy_password_len = 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) proxy_user_len;
if(proxy_user && proxy_user_len) {
/* the length must fit in a single byte */
if(proxy_user_len >= 255) {
failf(data, "Excessive user name length for proxy auth");
return CURLE_BAD_FUNCTION_ARGUMENT;
}
memcpy(socksreq + len, proxy_user, proxy_user_len);
}
len += proxy_user_len;
socksreq[len++] = (unsigned char) proxy_password_len;
if(proxy_password && proxy_password_len) {
/* the length must fit in a single byte */
if(proxy_password_len > 255) {
failf(data, "Excessive password length for proxy auth");
return CURLE_BAD_FUNCTION_ARGUMENT;
}
memcpy(socksreq + len, proxy_password, proxy_password_len);
}
len += proxy_password_len;
sxstate(conn, CONNECT_AUTH_SEND);
sx->outstanding = len;
sx->outp = socksreq;
}
/* FALLTHROUGH */
case CONNECT_AUTH_SEND:
result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
sx->outstanding, &written);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Failed to send SOCKS5 sub-negotiation request.");
return CURLE_COULDNT_CONNECT;
}
if(sx->outstanding != written) {
/* remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLE_OK;
}
sx->outp = socksreq;
sx->outstanding = 2;
sxstate(conn, CONNECT_AUTH_READ);
/* FALLTHROUGH */
case CONNECT_AUTH_READ:
result = Curl_read_plain(sockfd, (char *)sx->outp,
sx->outstanding, &actualread);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Unable to receive SOCKS5 sub-negotiation response.");
return CURLE_COULDNT_CONNECT;
}
if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLE_OK;
}
/* 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! */
sxstate(conn, CONNECT_REQ_INIT);
/* FALLTHROUGH */
CONNECT_REQ_INIT:
case CONNECT_REQ_INIT:
if(socks5_resolve_local) {
enum resolve_t rc = Curl_resolv(conn, hostname, remote_port,
FALSE, &dns);
if(rc == CURLRESOLV_ERROR)
return CURLE_COULDNT_RESOLVE_HOST;
if(rc == CURLRESOLV_PENDING) {
sxstate(conn, CONNECT_RESOLVING);
return CURLE_OK;
}
sxstate(conn, CONNECT_RESOLVED);
goto CONNECT_RESOLVED;
}
goto CONNECT_RESOLVE_REMOTE;
case CONNECT_RESOLVING:
/* check if we have the name resolved by now */
dns = Curl_fetch_addr(conn, hostname, (int)conn->port);
if(dns) {
#ifdef CURLRES_ASYNCH
conn->async.dns = dns;
conn->async.done = TRUE;
#endif
infof(data, "SOCKS5: hostname '%s' found\n", hostname);
}
if(!dns) {
result = Curl_resolv_check(data->conn, &dns);
if(!dns)
return result;
}
/* FALLTHROUGH */
CONNECT_RESOLVED:
case CONNECT_RESOLVED: {
Curl_addrinfo *hp = NULL;
if(dns)
hp = dns->addr;
if(!hp) {
failf(data, "Failed to resolve \"%s\" for SOCKS5 connect.",
hostname);
return CURLE_COULDNT_RESOLVE_HOST;
}
if(Curl_printable_address(hp, dest, sizeof(dest))) {
size_t destlen = strlen(dest);
msnprintf(dest + destlen, sizeof(dest) - destlen, ":%d", remote_port);
}
else {
strcpy(dest, "unknown");
}
len = 0;
socksreq[len++] = 5; /* version (SOCKS5) */
socksreq[len++] = 1; /* connect */
socksreq[len++] = 0; /* must be zero */
if(hp->ai_family == AF_INET) {
int i;
struct sockaddr_in *saddr_in;
socksreq[len++] = 1; /* ATYP: IPv4 = 1 */
saddr_in = (struct sockaddr_in *)(void *)hp->ai_addr;
for(i = 0; i < 4; i++) {
socksreq[len++] = ((unsigned char *)&saddr_in->sin_addr.s_addr)[i];
}
infof(data, "SOCKS5 connect to IPv4 %s (locally resolved)\n", dest);
}
#ifdef ENABLE_IPV6
else if(hp->ai_family == AF_INET6) {
int i;
struct sockaddr_in6 *saddr_in6;
socksreq[len++] = 4; /* ATYP: IPv6 = 4 */
saddr_in6 = (struct sockaddr_in6 *)(void *)hp->ai_addr;
for(i = 0; i < 16; i++) {
socksreq[len++] =
((unsigned char *)&saddr_in6->sin6_addr.s6_addr)[i];
}
infof(data, "SOCKS5 connect to IPv6 %s (locally resolved)\n", dest);
}
#endif
else {
hp = NULL; /* fail! */
failf(data, "SOCKS5 connection to %s not supported\n", dest);
}
Curl_resolv_unlock(data, dns); /* not used anymore from now on */
goto CONNECT_REQ_SEND;
}
CONNECT_RESOLVE_REMOTE:
case CONNECT_RESOLVE_REMOTE:
/* Authentication is complete, now specify destination to the proxy */
len = 0;
socksreq[len++] = 5; /* version (SOCKS5) */
socksreq[len++] = 1; /* connect */
socksreq[len++] = 0; /* must be zero */
if(!socks5_resolve_local) {
socksreq[len++] = 3; /* ATYP: domain name = 3 */
socksreq[len++] = (char) hostname_len; /* one byte address length */
memcpy(&socksreq[len], hostname, hostname_len); /* address w/o NULL */
len += hostname_len;
infof(data, "SOCKS5 connect to %s:%d (remotely resolved)\n",
hostname, remote_port);
}
/* FALLTHROUGH */
CONNECT_REQ_SEND:
case CONNECT_REQ_SEND:
/* PORT MSB */
socksreq[len++] = (unsigned char)((remote_port >> 8) & 0xff);
/* PORT LSB */
socksreq[len++] = (unsigned char)(remote_port & 0xff);
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(conn->socks5_gssapi_enctype) {
failf(data, "SOCKS5 GSS-API protection not yet implemented.");
return CURLE_COULDNT_CONNECT;
}
#endif
sx->outp = socksreq;
sx->outstanding = len;
sxstate(conn, CONNECT_REQ_SENDING);
/* FALLTHROUGH */
case CONNECT_REQ_SENDING:
result = Curl_write_plain(conn, sockfd, (char *)sx->outp,
sx->outstanding, &written);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Failed to send SOCKS5 connect request.");
return CURLE_COULDNT_CONNECT;
}
if(sx->outstanding != written) {
/* remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLE_OK;
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(conn->socks5_gssapi_enctype) {
failf(data, "SOCKS5 GSS-API protection not yet implemented.");
return CURLE_COULDNT_CONNECT;
}
#endif
sx->outstanding = 10; /* minimum packet size is 10 */
sx->outp = socksreq;
sxstate(conn, CONNECT_REQ_READ);
/* FALLTHROUGH */
case CONNECT_REQ_READ:
result = Curl_read_plain(sockfd, (char *)sx->outp,
sx->outstanding, &actualread);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Failed to receive SOCKS5 connect request ack.");
return CURLE_COULDNT_CONNECT;
}
else if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLE_OK;
}
if(socksreq[0] != 5) { /* version */
failf(data,
"SOCKS5 reply has wrong version, version should be 5.");
return CURLE_COULDNT_CONNECT;
}
else if(socksreq[1] != 0) { /* Anything besides 0 is an error */
failf(data, "Can't complete SOCKS5 connection to %s. (%d)",
hostname, (unsigned char)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];
len = 5 + addrlen + 2;
}
else if(socksreq[3] == 4) {
/* IPv6 */
len = 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(len > 10) {
sx->outstanding = len - 10; /* get the rest */
sx->outp = &socksreq[10];
sxstate(conn, CONNECT_REQ_READ_MORE);
}
else {
sxstate(conn, CONNECT_DONE);
break;
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
}
#endif
/* FALLTHROUGH */
case CONNECT_REQ_READ_MORE:
result = Curl_read_plain(sockfd, (char *)sx->outp,
sx->outstanding, &actualread);
if(result && (CURLE_AGAIN != result)) {
failf(data, "Failed to receive SOCKS5 connect request ack.");
return CURLE_COULDNT_CONNECT;
}
if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLE_OK;
}
sxstate(conn, CONNECT_DONE);
}
infof(data, "SOCKS5 request granted.\n");
*done = TRUE;
return CURLE_OK; /* Proxy was successful! */
}
#endif /* CURL_DISABLE_PROXY */
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