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bug1666 - Pass-through support for SOCKS5 authentication

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If a SOCKS5 client insists on authentication, allow it to
negotiate a connection with Tor's SOCKS server successfully.
Any credentials the client provides are ignored.

This allows Tor to work with SOCKS5 clients that can only
support 'authenticated' connections.

Also add a bunch of basic unit tests for SOCKS4/4a/5 support
in buffers.c.
This commit is contained in:
Robert Hogan 2010-08-03 22:28:55 +01:00
parent a62b79dfc9
commit bf136b94de
6 changed files with 294 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
doc/spec/socks-extensions.txt
View File

@ -31,8 +31,9 @@ Tor's extensions to the SOCKS protocol
SOCKS5:
- The (SOCKS5) "UDP ASSOCIATE" command is not supported.
- IPv6 is not supported in CONNECT commands.
- Only the "NO AUTHENTICATION" (SOCKS5) authentication method [00] is
supported.
- The "NO AUTHENTICATION" (SOCKS5) authentication method [00] and the
"USERNAME/PASSWORD" (SOCKS5) authentication method [02] are both
supported. Any credentials passed in the latter are ignored.
2. Name lookup

64
src/or/buffers.c
View File

@ -1633,40 +1633,74 @@ parse_socks(const char *data, size_t datalen, socks_request_t *req,
uint8_t socksver;
enum {socks4, socks4a} socks4_prot = socks4a;
char *next, *startaddr;
unsigned char usernamelen, passlen;
struct in_addr in;
socksver = *data;
switch (socksver) { /* which version of socks? */
case 1: /* socks5: username/password authentication request */
usernamelen = (unsigned char)*(buf->head->data + 1);
if (buf->datalen < 2u + usernamelen)
return 0;
buf_pullup(buf, 2u + usernamelen + 1, 0);
passlen = (unsigned char)*(buf->head->data + 2u + usernamelen);
if (buf->datalen < 2u + usernamelen + 1u + passlen)
return 0;
if (buf->datalen > 2u + usernamelen + 1u + passlen) {
log_warn(LD_APP,
"socks5: Malformed username/password. Rejecting.");
return -1;
}
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 5;
req->reply[1] = 0; /* authentication successful */
buf_clear(buf);
log_debug(LD_APP,
"socks5: Accepted username/password without checking.");
return 0;
case 5: /* socks5 */
if (req->socks_version != 5) { /* we need to negotiate a method */
unsigned char nummethods = (unsigned char)*(data+1);
int r=0;
tor_assert(!req->socks_version);
if (datalen < 2u+nummethods) {
*want_length_out = 2u+nummethods;
return 0;
}
if (!nummethods || !memchr(data+2, 0, nummethods)) {
log_warn(LD_APP,
"socks5: offered methods don't include 'no auth'. "
"Rejecting.");
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 5;
req->reply[1] = '\xFF'; /* reject all methods */
buf_pullup(buf, 2u+nummethods, 0);
if (!nummethods)
return -1;
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 5; /* socks5 reply */
if (memchr(buf->head->data+2, SOCKS_NO_AUTH, nummethods)) {
req->reply[1] = SOCKS_NO_AUTH; /* tell client to use "none" auth
method */
req->socks_version = 5; /* remember we've already negotiated auth */
log_debug(LD_APP,"socks5: accepted method 0 (no authentication)");
r=0;
}else if (memchr(buf->head->data+2, SOCKS_USER_PASS,nummethods)) {
req->reply[1] = SOCKS_USER_PASS; /* tell client to use "user/pass"
auth method */
req->socks_version = 5; /* remember we've already negotiated auth */
log_debug(LD_APP,"socks5: accepted method 2 (username/password)");
r=0;
} else {
log_warn(LD_APP,
"socks5: offered methods don't include 'no auth' or "
"username/password. Rejecting.");
req->reply[1] = '\xFF'; /* reject all methods */
r=-1;
}
/* remove packet from buf. also remove any other extraneous
* bytes, to support broken socks clients. */
*drain_out = -1;
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 5; /* socks5 reply */
req->reply[1] = 0; /* tell client to use "none" auth method */
req->socks_version = 5; /* remember we've already negotiated auth */
log_debug(LD_APP,"socks5: accepted method 0");
return 0;
return r;
}
/* we know the method; read in the request */
log_debug(LD_APP,"socks5: checking request");
@ -1761,8 +1795,8 @@ parse_socks(const char *data, size_t datalen, socks_request_t *req,
}
tor_assert(0);
case 4: /* socks4 */
/* http://archive.socks.permeo.com/protocol/socks4.protocol */
/* http://archive.socks.permeo.com/protocol/socks4a.protocol */
/* http://ss5.sourceforge.net/socks4.protocol.txt */
/* http://ss5.sourceforge.net/socks4A.protocol.txt */
req->socks_version = 4;
if (datalen < SOCKS4_NETWORK_LEN) {/* basic info available? */

3
src/or/config.c
View File

@ -542,7 +542,6 @@ static int options_transition_affects_workers(or_options_t *old_options,
static int options_transition_affects_descriptor(or_options_t *old_options,
or_options_t *new_options);
static int check_nickname_list(const char *lst, const char *name, char **msg);
static void config_register_addressmaps(or_options_t *options);
static int parse_bridge_line(const char *line, int validate_only);
static int parse_dir_server_line(const char *line,
@ -4314,7 +4313,7 @@ get_torrc_fname(void)
/** Adjust the address map based on the MapAddress elements in the
* configuration <b>options</b>
*/
static void
void
config_register_addressmaps(or_options_t *options)
{
smartlist_t *elts;

2
src/or/config.h
View File

@ -76,5 +76,7 @@ uint32_t get_effective_bwburst(or_options_t *options);
or_options_t *options_new(void);
#endif
void config_register_addressmaps(or_options_t *options);
#endif

2
src/or/or.h
View File

@ -3067,6 +3067,8 @@ static INLINE void or_state_mark_dirty(or_state_t *state, time_t when)
#define MAX_SOCKS_REPLY_LEN 1024
#define MAX_SOCKS_ADDR_LEN 256
#define SOCKS_NO_AUTH 0x00
#define SOCKS_USER_PASS 0x02
/** Please open a TCP connection to this addr:port. */
#define SOCKS_COMMAND_CONNECT 0x01

237
src/test/test.c
View File

@ -197,6 +197,207 @@ free_pregenerated_keys(void)
}
}
/** Helper: Perform supported SOCKS 5 commands */
static void
test_buffers_socks4_unsupported_commands_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/* SOCKS 4 Send BIND [02] to IP address 2.2.2.2:4369 */
cp = "\x04\x02\x11\x11\x02\x02\x02\x02\x00";
write_to_buf(cp, 9, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == -1);
test_eq(4, socks->socks_version);
test_eq(0, socks->replylen); /* XXX: shouldn't tor reply? */
done:
;
}
/** Helper: Perform supported SOCKS 5 commands */
static void
test_buffers_socks4_supported_commands_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/* SOCKS 4 Send CONNECT [01] to IP address 2.2.2.2:4369 */
cp = "\x04\x01\x11\x11\x02\x02\x02\x02\x00";
write_to_buf(cp, 9, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == 1);
test_eq(4, socks->socks_version);
test_eq(0, socks->replylen); /* XXX: shouldn't tor reply? */
test_streq("2.2.2.2", socks->address);
test_eq(4369, socks->port);
/* SOCKS 4 Send CONNECT [01] to IP address 2.2.2.2:4369 with userid*/
cp = "\x04\x01\x11\x11\x02\x02\x02\x02\x02me\x00";
write_to_buf(cp, 12, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == 1);
test_eq(4, socks->socks_version);
test_eq(0, socks->replylen); /* XXX: shouldn't tor reply? */
test_streq("2.2.2.2", socks->address);
test_eq(4369, socks->port);
/* SOCKS 4a Send RESOLVE [F0] request for torproject.org:4369 */
cp = "\x04\xF0\x01\x01\x00\x00\x00\x02\x02me\x00tor.org\x00";
write_to_buf(cp, 20, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(4, socks->socks_version);
test_eq(0, socks->replylen); /* XXX: shouldn't tor reply? */
test_streq("tor.org", socks->address);
done:
;
}
/** Helper: Perform supported SOCKS 5 commands */
static void
test_buffers_socks5_unsupported_commands_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/* SOCKS 5 Send unsupported BIND [02] command */
cp = "\x05\x02\x00\x01\x02\x02\x02\x02\x01\x01";
write_to_buf(cp, 10, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == -1);
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]); /* XXX: shouldn't tor reply 'command
not supported' [07]? */
/* SOCKS 5 Send unsupported UDP_ASSOCIATE [03] command */
cp = "\x05\x03\x00\x01\x02\x02\x02\x02\x01\x01";
write_to_buf(cp, 10, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == -1);
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]); /* XXX: shouldn't tor reply 'command
not supported' [07]? */
done:
;
}
/** Helper: Perform supported SOCKS 5 commands */
static void
test_buffers_socks5_supported_commands_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/* SOCKS 5 Send CONNECT [01] to IP address 2.2.2.2:4369 */
cp = "\x05\x01\x00\x01\x02\x02\x02\x02\x11\x11";
write_to_buf(cp, 10, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == 1);
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
test_streq("2.2.2.2", socks->address);
test_eq(4369, socks->port);
/* SOCKS 5 Send CONNECT [01] to FQDN torproject.org:4369 */
cp = "\x05\x01\x00\x03\x07tor.org\x11\x11";
write_to_buf(cp, 14, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
test_streq("tor.org", socks->address);
test_eq(4369, socks->port);
/* SOCKS 5 Send RESOLVE [F0] request for torproject.org:4369 */
cp = "\x05\xF0\x00\x03\x07tor.org";
write_to_buf(cp, 14, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
test_streq("tor.org", socks->address);
/* SOCKS 5 Send RESOLVE_PTR [F1] for IP address 2.2.2.2 */
cp = "\x05\xF1\x00\x01\x02\x02\x02\x02";
write_to_buf(cp, 10, buf);
test_assert(fetch_from_buf_socks(buf, socks, get_options()->TestSocks,
get_options()->SafeSocks) == 1);
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
test_streq("2.2.2.2", socks->address);
done:
;
}
/** Helper: Perform SOCKS 5 authentication */
static void
test_buffers_socks5_no_authenticate_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/*SOCKS 5 No Authentication */
cp = "\x05\x01\x00";
write_to_buf(cp, 3, buf);
test_assert(!fetch_from_buf_socks(buf, socks,
get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(SOCKS_NO_AUTH, socks->reply[1]);
/*SOCKS 5 Send username/password anyway - pretend to be broken */
cp = "\x01\x02\x01\x01\x02\x01\x01";
write_to_buf(cp, 7, buf);
test_assert(!fetch_from_buf_socks(buf, socks,
get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
done:
;
}
/** Helper: Perform SOCKS 5 authentication */
static void
test_buffers_socks5_authenticate_helper(const char *cp, buf_t *buf,
socks_request_t *socks)
{
/* SOCKS 5 Negotiate username/password authentication */
cp = "\x05\x01\x02";
write_to_buf(cp, 3, buf);
test_assert(!fetch_from_buf_socks(buf, socks,
get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(SOCKS_USER_PASS, socks->reply[1]);
test_eq(5, socks->socks_version);
/* SOCKS 5 Send username/password */
cp = "\x01\x02me\x02me";
write_to_buf(cp, 7, buf);
test_assert(!fetch_from_buf_socks(buf, socks,
get_options()->TestSocks,
get_options()->SafeSocks));
test_eq(5, socks->socks_version);
test_eq(2, socks->replylen);
test_eq(5, socks->reply[0]);
test_eq(0, socks->reply[1]);
done:
;
}
/** Run unit tests for buffers.c */
static void
test_buffers(void)
@ -206,6 +407,7 @@ test_buffers(void)
buf_t *buf = NULL, *buf2 = NULL;
const char *cp;
socks_request_t *socks;
int j;
size_t r;
@ -363,6 +565,41 @@ test_buffers(void)
buf_free(buf);
buf = NULL;
/* Test fetch_from_buf_socks() */
buf = buf_new_with_capacity(256);
socks = tor_malloc_zero(sizeof(socks_request_t));;
config_register_addressmaps(get_options());
/* A SOCKS 5 client that only supports authentication */
test_buffers_socks5_authenticate_helper(cp, buf, socks);
test_buffers_socks5_supported_commands_helper(cp, buf, socks);
test_buffers_socks5_unsupported_commands_helper(cp, buf, socks);
tor_free(socks);
buf_free(buf);
buf = NULL;
buf = buf_new_with_capacity(256);
socks = tor_malloc_zero(sizeof(socks_request_t));;
/* A SOCKS 5 client that doesn't want authentication */
test_buffers_socks5_no_authenticate_helper(cp, buf, socks);
test_buffers_socks5_supported_commands_helper(cp, buf, socks);
test_buffers_socks5_unsupported_commands_helper(cp, buf, socks);
tor_free(socks);
buf_free(buf);
buf = NULL;
buf = buf_new_with_capacity(256);
socks = tor_malloc_zero(sizeof(socks_request_t));;
/* A SOCKS 4(a) client */
test_buffers_socks4_supported_commands_helper(cp, buf, socks);
test_buffers_socks4_unsupported_commands_helper(cp, buf, socks);
tor_free(socks);
buf_free(buf);
buf = NULL;
done:
if (buf)
buf_free(buf);