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curl/lib/socks.c
Daniel Stenberg 0b60d3685e
socks: check for DNS entries with the right port number 
The resolve call is done with the right port number, but the subsequent
check used the wrong one, which then could find a previous resolve which
would return and leave the fresh resolve "incomplete" and leaking
memory.

Fixes #6247
Closes #6253
2020-11-26 22:29:34 +01:00

1032 lines
32 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.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 timeout_ms = Curl_timeleft(conn->data, NULL, TRUE);
if(timeout_ms < 0) {
/* we already got the timeout */
result = CURLE_OPERATION_TIMEDOUT;
break;
}
if(!timeout_ms)
timeout_ms = TIMEDIFF_T_MAX;
if(SOCKET_READABLE(sockfd, timeout_ms) <= 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)"
*/
CURLproxycode 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 CURLPX_RESOLVE_HOST;
else if(rc == CURLRESOLV_PENDING) {
sxstate(conn, CONNECT_RESOLVING);
infof(data, "SOCKS4 non-blocking resolve of %s\n", hostname);
return CURLPX_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) {
if(result)
return CURLPX_RESOLVE_HOST;
return CURLPX_OK;
}
}
/* FALLTHROUGH */
CONNECT_RESOLVED:
case CONNECT_RESOLVED: {
struct 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 CURLPX_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 user name, can't use!\n");
return CURLPX_LONG_USER;
}
/* copy the proxy name WITH trailing zero */
memcpy(socksreq + 8, proxy_user, plen + 1);
}
/*
* Make connection
*/
{
size_t packetsize = 9 +
strlen((char *)socksreq + 8); /* size including NUL */
/* If SOCKS4a, set special invalid IP address 0.0.0.x */
if(protocol4a) {
size_t hostnamelen = 0;
socksreq[4] = 0;
socksreq[5] = 0;
socksreq[6] = 0;
socksreq[7] = 1;
/* append hostname */
hostnamelen = strlen(hostname) + 1; /* length including NUL */
if(hostnamelen <= 255)
strcpy((char *)socksreq + packetsize, hostname);
else {
failf(data, "SOCKS4: too long host name");
return CURLPX_LONG_HOSTNAME;
}
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 CURLPX_SEND_CONNECT;
}
if(written != sx->outstanding) {
/* not done, remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLPX_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 CURLPX_RECV_CONNECT;
}
else if(!result && !actualread) {
/* connection closed */
failf(data, "connection to proxy closed");
return CURLPX_CLOSED;
}
else if(actualread != sx->outstanding) {
/* remain in reading state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLPX_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 CURLPX_BAD_VERSION;
}
/* 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 CURLPX_REQUEST_FAILED;
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 CURLPX_IDENTD;
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 CURLPX_IDENTD_DIFFER;
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 CURLPX_UNKNOWN_FAIL;
}
*done = TRUE;
return CURLPX_OK; /* Proxy was successful! */
}
/*
* This function logs in to a SOCKS5 proxy and sends the specifics to the final
* destination server.
*/
CURLproxycode 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 CURLPX_SEND_CONNECT;
}
if(written != idx) {
sxstate(conn, CONNECT_SOCKS_SEND);
sx->outstanding = idx - written;
sx->outp = &socksreq[written];
return CURLPX_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 CURLPX_SEND_CONNECT;
}
if(written != sx->outstanding) {
/* not done, remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLPX_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 CURLPX_RECV_CONNECT;
}
else if(!result && !actualread) {
/* connection closed */
failf(data, "Connection to proxy closed");
return CURLPX_CLOSED;
}
else if(actualread != sx->outstanding) {
/* remain in reading state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLPX_OK;
}
else if(socksreq[0] != 5) {
failf(data, "Received invalid version in initial SOCKS5 response.");
return CURLPX_BAD_VERSION;
}
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 CURLPX_GSSAPI;
}
}
#endif
else {
/* error */
if(!allow_gssapi && (socksreq[1] == 1)) {
failf(data,
"SOCKS5 GSSAPI per-message authentication is not supported.");
return CURLPX_GSSAPI_PERMSG;
}
else if(socksreq[1] == 255) {
failf(data, "No authentication method was acceptable.");
return CURLPX_NO_AUTH;
}
}
failf(data,
"Undocumented SOCKS5 mode attempted to be used by server.");
return CURLPX_UNKNOWN_MODE;
#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 CURLPX_LONG_USER;
}
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 CURLPX_LONG_PASSWD;
}
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 CURLPX_SEND_AUTH;
}
if(sx->outstanding != written) {
/* remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLPX_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 CURLPX_RECV_AUTH;
}
else if(!result && !actualread) {
/* connection closed */
failf(data, "connection to proxy closed");
return CURLPX_CLOSED;
}
else if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLPX_OK;
}
/* ignore the first (VER) byte */
else if(socksreq[1] != 0) { /* status */
failf(data, "User was rejected by the SOCKS5 server (%d %d).",
socksreq[0], socksreq[1]);
return CURLPX_USER_REJECTED;
}
/* 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 CURLPX_RESOLVE_HOST;
if(rc == CURLRESOLV_PENDING) {
sxstate(conn, CONNECT_RESOLVING);
return CURLPX_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, remote_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) {
if(result)
return CURLPX_RESOLVE_HOST;
return CURLPX_OK;
}
}
/* FALLTHROUGH */
CONNECT_RESOLVED:
case CONNECT_RESOLVED: {
struct Curl_addrinfo *hp = NULL;
size_t destlen;
if(dns)
hp = dns->addr;
if(!hp) {
failf(data, "Failed to resolve \"%s\" for SOCKS5 connect.",
hostname);
return CURLPX_RESOLVE_HOST;
}
Curl_printable_address(hp, dest, sizeof(dest));
destlen = strlen(dest);
msnprintf(dest + destlen, sizeof(dest) - destlen, ":%d", remote_port);
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 CURLPX_GSSAPI_PROTECTION;
}
#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 CURLPX_SEND_REQUEST;
}
if(sx->outstanding != written) {
/* remain in state */
sx->outstanding -= written;
sx->outp += written;
return CURLPX_OK;
}
#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
if(conn->socks5_gssapi_enctype) {
failf(data, "SOCKS5 GSS-API protection not yet implemented.");
return CURLPX_GSSAPI_PROTECTION;
}
#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 CURLPX_RECV_REQACK;
}
else if(!result && !actualread) {
/* connection closed */
failf(data, "connection to proxy closed");
return CURLPX_CLOSED;
}
else if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLPX_OK;
}
if(socksreq[0] != 5) { /* version */
failf(data,
"SOCKS5 reply has wrong version, version should be 5.");
return CURLPX_BAD_VERSION;
}
else if(socksreq[1] != 0) { /* Anything besides 0 is an error */
CURLproxycode rc = CURLPX_REPLY_UNASSIGNED;
int code = socksreq[1];
failf(data, "Can't complete SOCKS5 connection to %s. (%d)",
hostname, (unsigned char)socksreq[1]);
if(code < 9) {
/* RFC 1928 section 6 lists: */
static const CURLproxycode lookup[] = {
CURLPX_OK,
CURLPX_REPLY_GENERAL_SERVER_FAILURE,
CURLPX_REPLY_NOT_ALLOWED,
CURLPX_REPLY_NETWORK_UNREACHABLE,
CURLPX_REPLY_HOST_UNREACHABLE,
CURLPX_REPLY_CONNECTION_REFUSED,
CURLPX_REPLY_TTL_EXPIRED,
CURLPX_REPLY_COMMAND_NOT_SUPPORTED,
CURLPX_REPLY_ADDRESS_TYPE_NOT_SUPPORTED,
};
rc = lookup[code];
}
return rc;
}
/* 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;
}
else if(socksreq[3] == 1) {
len = 4 + 4 + 2;
}
else {
failf(data, "SOCKS5 reply has wrong address type.");
return CURLPX_BAD_ADDRESS_TYPE;
}
/* 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 CURLPX_RECV_ADDRESS;
}
else if(!result && !actualread) {
/* connection closed */
failf(data, "connection to proxy closed");
return CURLPX_CLOSED;
}
else if(actualread != sx->outstanding) {
/* remain in state */
sx->outstanding -= actualread;
sx->outp += actualread;
return CURLPX_OK;
}
sxstate(conn, CONNECT_DONE);
}
infof(data, "SOCKS5 request granted.\n");
*done = TRUE;
return CURLPX_OK; /* Proxy was successful! */
}
#endif /* CURL_DISABLE_PROXY */
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