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Make a distinction between truncated message and expecting more messages

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This commit is contained in:
rl1987
2018-05-22 16:28:15 +02:00
committed by Nick Mathewson
parent fb105404f2
commit 01cf3007b5
1 changed files with 107 additions and 97 deletions
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src/or/proto_socks.c
+107 -97
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@@ -17,12 +17,23 @@
#include "trunnel/socks5.h"
#include "or/socks_request_st.h"
typedef enum {
SOCKS_RESULT_INVALID = -1,
SOCKS_RESULT_TRUNCATED = 0,
SOCKS_RESULT_DONE = 1,
SOCKS_RESULT_MORE_EXPECTED = 2,
} socks_result_t;
static void socks_request_set_socks5_error(socks_request_t *req,
socks5_reply_status_t reason);
static int parse_socks(const char *data, size_t datalen, socks_request_t *req,
int log_sockstype, int safe_socks, size_t *drain_out,
size_t *want_length_out);
static socks_result_t parse_socks(const char *data,
size_t datalen,
socks_request_t *req,
int log_sockstype,
int safe_socks,
size_t *drain_out,
size_t *want_length_out);
static int parse_socks_client(const uint8_t *data, size_t datalen,
int state, char **reason,
ssize_t *drain_out);
@@ -86,13 +97,13 @@ socks_request_free_(socks_request_t *req)
tor_free(req);
}
static int
static socks_result_t
parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
size_t datalen, int *is_socks4a, size_t *drain_out)
{
// http://ss5.sourceforge.net/socks4.protocol.txt
// http://ss5.sourceforge.net/socks4A.protocol.txt
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
tor_addr_t destaddr;
tor_assert(is_socks4a);
@@ -110,13 +121,13 @@ parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
if (parsed == -1) {
log_warn(LD_APP, "socks4: parsing failed - invalid request.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
} else if (parsed == -2) {
res = 0;
res = SOCKS_RESULT_TRUNCATED;
if (datalen > 1024) { // XXX
log_warn(LD_APP, "socks4: parsing failed - invalid request.");
res = -1;
res = SOCKS_RESULT_INVALID;
}
goto end;
}
@@ -133,7 +144,7 @@ parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
if ((!req->port && req->command != SOCKS_COMMAND_RESOLVE) ||
dest_ip == 0) {
log_warn(LD_APP, "socks4: Port or DestIP is zero. Rejecting.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -144,7 +155,7 @@ parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
if (username && usernamelen) {
if (usernamelen > MAX_SOCKS_MESSAGE_LEN) {
log_warn(LD_APP, "Socks4 user name too long; rejecting.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -168,7 +179,7 @@ parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
strlcpy(req->address, trunnel_hostname, sizeof(req->address));
} else {
log_warn(LD_APP, "socks4: Destaddr too long. Rejecting.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
} else {
@@ -176,7 +187,7 @@ parse_socks4_request(const uint8_t *raw_data, socks_request_t *req,
if (!tor_addr_to_str(req->address, &destaddr,
MAX_SOCKS_ADDR_LEN, 0)) {
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
}
@@ -205,7 +216,7 @@ process_socks4_request(const socks_request_t *req, int is_socks4a,
log_unsafe_socks_warning(4, req->address, req->port, safe_socks);
if (safe_socks)
return -1;
return SOCKS_RESULT_INVALID;
}
if (req->command != SOCKS_COMMAND_CONNECT &&
@@ -214,7 +225,7 @@ process_socks4_request(const socks_request_t *req, int is_socks4a,
* socks4.) */
log_warn(LD_APP, "socks4: command %d not recognized. Rejecting.",
req->command);
return -1;
return SOCKS_RESULT_INVALID;
}
if (is_socks4a) {
@@ -230,18 +241,18 @@ process_socks4_request(const socks_request_t *req, int is_socks4a,
"Your application (using socks4 to port %d) gave Tor "
"a malformed hostname: %s. Rejecting the connection.",
req->port, escaped_safe_str_client(req->address));
return -1;
return SOCKS_RESULT_INVALID;
}
return 1;
return SOCKS_RESULT_DONE;
}
static int
static socks_result_t
parse_socks5_methods_request(const uint8_t *raw_data, socks_request_t *req,
size_t datalen, int *have_user_pass,
int *have_no_auth, size_t *drain_out)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
socks5_client_version_t *trunnel_req;
ssize_t parsed = socks5_client_version_parse(&trunnel_req, raw_data,
@@ -258,14 +269,14 @@ parse_socks5_methods_request(const uint8_t *raw_data, socks_request_t *req,
if (parsed == -1) {
log_warn(LD_APP, "socks5: parsing failed - invalid version "
"id/method selection message.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
} else if (parsed == -2) {
res = 0;
res = SOCKS_RESULT_TRUNCATED;
if (datalen > 1024) { // XXX
log_warn(LD_APP, "socks5: parsing failed - invalid version "
"id/method selection message.");
res = -1;
res = SOCKS_RESULT_INVALID;
}
goto end;
}
@@ -275,7 +286,7 @@ parse_socks5_methods_request(const uint8_t *raw_data, socks_request_t *req,
size_t n_methods = (size_t)socks5_client_version_get_n_methods(trunnel_req);
if (n_methods == 0) {
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -299,11 +310,11 @@ parse_socks5_methods_request(const uint8_t *raw_data, socks_request_t *req,
return res;
}
static int
static socks_result_t
process_socks5_methods_request(socks_request_t *req, int have_user_pass,
int have_no_auth)
{
int res = 0;
socks_result_t res = SOCKS_RESULT_DONE;
socks5_server_method_t *trunnel_resp = socks5_server_method_new();
socks5_server_method_set_version(trunnel_resp, 5);
@@ -328,14 +339,14 @@ process_socks5_methods_request(socks_request_t *req, int have_user_pass,
"socks5: offered methods don't include 'no auth' or "
"username/password. Rejecting.");
socks5_server_method_set_method(trunnel_resp, 0xFF); // reject all
res = -1;
res = SOCKS_RESULT_INVALID;
}
const char *errmsg = socks5_server_method_check(trunnel_resp);
if (errmsg) {
log_warn(LD_APP, "socks5: method selection validation failed: %s",
errmsg);
res = -1;
res = SOCKS_RESULT_INVALID;
} else {
ssize_t encoded =
socks5_server_method_encode(req->reply, sizeof(req->reply),
@@ -343,7 +354,7 @@ process_socks5_methods_request(socks_request_t *req, int have_user_pass,
if (encoded < 0) {
log_warn(LD_APP, "socks5: method selection encoding failed");
res = -1;
res = SOCKS_RESULT_INVALID;
} else {
req->replylen = (size_t)encoded;
}
@@ -353,11 +364,11 @@ process_socks5_methods_request(socks_request_t *req, int have_user_pass,
return res;
}
static int
static socks_result_t
parse_socks5_userpass_auth(const uint8_t *raw_data, socks_request_t *req,
size_t datalen, size_t *drain_out)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
socks5_client_userpass_auth_t *trunnel_req = NULL;
ssize_t parsed = socks5_client_userpass_auth_parse(&trunnel_req, raw_data,
datalen);
@@ -367,10 +378,10 @@ parse_socks5_userpass_auth(const uint8_t *raw_data, socks_request_t *req,
if (parsed == -1) {
log_warn(LD_APP, "socks5: parsing failed - invalid user/pass "
"authentication message.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
} else if (parsed == -2) {
res = 0;
res = SOCKS_RESULT_TRUNCATED;
goto end;
}
@@ -405,21 +416,21 @@ parse_socks5_userpass_auth(const uint8_t *raw_data, socks_request_t *req,
return res;
}
static int
static socks_result_t
process_socks5_userpass_auth(socks_request_t *req)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
socks5_server_userpass_auth_t *trunnel_resp =
socks5_server_userpass_auth_new();
if (req->socks_version != 5) {
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
if (req->auth_type != SOCKS_USER_PASS &&
req->auth_type != SOCKS_NO_AUTH) {
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -430,7 +441,7 @@ process_socks5_userpass_auth(socks_request_t *req)
if (errmsg) {
log_warn(LD_APP, "socks5: server userpass auth validation failed: %s",
errmsg);
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -440,7 +451,7 @@ process_socks5_userpass_auth(socks_request_t *req)
if (encoded < 0) {
log_warn(LD_APP, "socks5: server userpass auth encoding failed");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -451,21 +462,21 @@ process_socks5_userpass_auth(socks_request_t *req)
return res;
}
static int
static socks_result_t
parse_socks5_client_request(const uint8_t *raw_data, socks_request_t *req,
size_t datalen, size_t *drain_out)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
tor_addr_t destaddr;
socks5_client_request_t *trunnel_req = NULL;
ssize_t parsed =
socks5_client_request_parse(&trunnel_req, raw_data, datalen);
if (parsed == -1) {
log_warn(LD_APP, "socks5: parsing failed - invalid client request");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
} else if (parsed == -2) {
res = 0;
res = SOCKS_RESULT_TRUNCATED;
goto end;
}
@@ -473,7 +484,7 @@ parse_socks5_client_request(const uint8_t *raw_data, socks_request_t *req,
*drain_out = (size_t)parsed;
if (socks5_client_request_get_version(trunnel_req) != 5) {
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -517,18 +528,18 @@ parse_socks5_client_request(const uint8_t *raw_data, socks_request_t *req,
return res;
}
static int
static socks_result_t
process_socks5_client_request(socks_request_t *req,
int log_sockstype,
int safe_socks)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
if (req->command != SOCKS_COMMAND_CONNECT &&
req->command != SOCKS_COMMAND_RESOLVE &&
req->command != SOCKS_COMMAND_RESOLVE_PTR) {
socks_request_set_socks5_error(req,SOCKS5_COMMAND_NOT_SUPPORTED);
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -539,7 +550,7 @@ process_socks5_client_request(socks_request_t *req,
log_warn(LD_APP, "socks5 received RESOLVE_PTR command with "
"hostname type. Rejecting.");
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -551,7 +562,7 @@ process_socks5_client_request(socks_request_t *req,
"a malformed hostname: %s. Rejecting the connection.",
req->port, escaped_safe_str_client(req->address));
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
@@ -561,7 +572,7 @@ process_socks5_client_request(socks_request_t *req,
log_unsafe_socks_warning(5, req->address, req->port, safe_socks);
if (safe_socks) {
socks_request_set_socks5_error(req, SOCKS5_NOT_ALLOWED);
res = -1;
res = SOCKS_RESULT_INVALID;
goto end;
}
}
@@ -577,12 +588,12 @@ process_socks5_client_request(socks_request_t *req,
return res;
}
static int
static socks_result_t
handle_socks_message(const uint8_t *raw_data, size_t datalen,
socks_request_t *req, int log_sockstype,
int safe_socks, size_t *drain_out)
{
int res = 1;
socks_result_t res = SOCKS_RESULT_DONE;
uint8_t socks_version = raw_data[0];
@@ -596,25 +607,20 @@ handle_socks_message(const uint8_t *raw_data, size_t datalen,
}
int is_socks4a = 0;
int parse_status =
parse_socks4_request((const uint8_t *)raw_data, req, datalen,
&is_socks4a, drain_out);
res = parse_socks4_request((const uint8_t *)raw_data, req, datalen,
&is_socks4a, drain_out);
if (parse_status != 1) {
res = parse_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
int process_status = process_socks4_request(req, is_socks4a,
log_sockstype,
safe_socks);
res = process_socks4_request(req, is_socks4a,log_sockstype,
safe_socks);
if (process_status != 1) {
res = process_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
res = 1;
goto end;
} else if (socks_version == 5) {
if (datalen < 2) { /* version and another byte */
@@ -624,68 +630,58 @@ handle_socks_message(const uint8_t *raw_data, size_t datalen,
/* RFC1929 SOCKS5 username/password subnegotiation. */
if (!req->got_auth && (raw_data[0] == 1 ||
req->auth_type == SOCKS_USER_PASS)) {
int parse_status = parse_socks5_userpass_auth(raw_data, req, datalen,
drain_out);
res = parse_socks5_userpass_auth(raw_data, req, datalen,
drain_out);
if (parse_status != 1) {
res = parse_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
int process_status = process_socks5_userpass_auth(req);
if (process_status != 1) {
res = process_status;
res = process_socks5_userpass_auth(req);
if (res != SOCKS_RESULT_DONE) {
goto end;
}
res = 0;
res = SOCKS_RESULT_MORE_EXPECTED;
goto end;
} else if (req->socks_version != 5) {
int have_user_pass, have_no_auth;
int parse_status = parse_socks5_methods_request(raw_data,
req,
datalen,
&have_user_pass,
&have_no_auth,
drain_out);
res = parse_socks5_methods_request(raw_data, req, datalen,
&have_user_pass,
&have_no_auth,
drain_out);
if (parse_status != 1) {
res = parse_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
int process_status = process_socks5_methods_request(req,
have_user_pass,
have_no_auth);
res = process_socks5_methods_request(req, have_user_pass,
have_no_auth);
if (process_status == -1) {
res = process_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
res = 0;
res = SOCKS_RESULT_MORE_EXPECTED;
goto end;
} else {
int parse_status = parse_socks5_client_request(raw_data, req,
datalen, drain_out);
if (parse_status != 1) {
res = parse_socks5_client_request(raw_data, req,
datalen, drain_out);
if (res != SOCKS_RESULT_DONE) {
socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR);
res = parse_status;
goto end;
}
int process_status = process_socks5_client_request(req,
log_sockstype,
safe_socks);
res = process_socks5_client_request(req, log_sockstype,
safe_socks);
if (process_status != 1) {
res = process_status;
if (res != SOCKS_RESULT_DONE) {
goto end;
}
}
} else {
*drain_out = datalen;
res = -1;
res = SOCKS_RESULT_INVALID;
}
end:
@@ -726,6 +722,7 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
size_t n_drain;
size_t want_length = 128;
const char *head = NULL;
socks_result_t socks_res;
if (buf_datalen(buf) < 2) { /* version and another byte */
res = 0;
@@ -739,13 +736,26 @@ fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
tor_assert(head && datalen >= 2);
want_length = 0;
res = parse_socks(head, datalen, req, log_sockstype,
safe_socks, &n_drain, &want_length);
socks_res = parse_socks(head, datalen, req, log_sockstype,
safe_socks, &n_drain, &want_length);
if (res == -1)
if (socks_res == SOCKS_RESULT_INVALID)
buf_clear(buf);
else if (n_drain > 0)
else if (socks_res != SOCKS_RESULT_TRUNCATED && n_drain > 0)
buf_drain(buf, n_drain);
switch (socks_res) {
case SOCKS_RESULT_INVALID:
res = -1;
break;
case SOCKS_RESULT_DONE:
res = 1;
break;
case SOCKS_RESULT_TRUNCATED:
case SOCKS_RESULT_MORE_EXPECTED:
res = 0;
break;
}
} while (res == 0 && head && buf_datalen(buf) >= 2);
end: