diff options
Diffstat (limited to 'src/tools/tor-resolve.c')
| -rw-r--r-- | src/tools/tor-resolve.c | 402 |
1 files changed, 298 insertions, 104 deletions
diff --git a/src/tools/tor-resolve.c b/src/tools/tor-resolve.c index 6a84abe557..e6d6bddcdb 100644 --- a/src/tools/tor-resolve.c +++ b/src/tools/tor-resolve.c @@ -1,5 +1,5 @@ /* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson - * Copyright (c) 2007-2019, The Tor Project, Inc. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ /* See LICENSE for licensing information */ @@ -15,6 +15,7 @@ #include "lib/string/util_string.h" #include "lib/net/socks5_status.h" +#include "trunnel/socks5.h" #include <stdio.h> #include <stdlib.h> @@ -44,73 +45,211 @@ #define RESPONSE_LEN_4 8 #define log_sock_error(act, _s) \ - STMT_BEGIN log_fn(LOG_ERR, LD_NET, "Error while %s: %s", act, \ - tor_socket_strerror(tor_socket_errno(_s))); STMT_END + STMT_BEGIN \ + log_fn(LOG_ERR, LD_NET, "Error while %s: %s", act, \ + tor_socket_strerror(tor_socket_errno(_s))); \ + STMT_END static void usage(void) ATTR_NORETURN; +/** + * Set <b>out</b> to a pointer to newly allocated buffer containing + * SOCKS4a RESOLVE request with <b>username</b> and <b>hostname</b>. + * Return number of bytes in the buffer if succeeded or -1 if failed. + */ +static ssize_t +build_socks4a_resolve_request(uint8_t **out, + const char *username, + const char *hostname) +{ + tor_assert(out); + tor_assert(username); + tor_assert(hostname); + + const char *errmsg = NULL; + uint8_t *output = NULL; + socks4_client_request_t *rq = socks4_client_request_new(); + + socks4_client_request_set_version(rq, 4); + socks4_client_request_set_command(rq, CMD_RESOLVE); + socks4_client_request_set_port(rq, 0); + socks4_client_request_set_addr(rq, 0x00000001u); + socks4_client_request_set_username(rq, username); + socks4_client_request_set_socks4a_addr_hostname(rq, hostname); + + errmsg = socks4_client_request_check(rq); + if (errmsg) { + goto cleanup; + } + + ssize_t encoded_len = socks4_client_request_encoded_len(rq); + if (encoded_len <= 0) { + errmsg = "socks4_client_request_encoded_len failed"; + goto cleanup; + } + + output = tor_malloc(encoded_len); + memset(output, 0, encoded_len); + + encoded_len = socks4_client_request_encode(output, encoded_len, rq); + if (encoded_len <= 0) { + errmsg = "socks4_client_request_encode failed"; + goto cleanup; + } + + *out = output; + + cleanup: + socks4_client_request_free(rq); + if (errmsg) { + log_err(LD_NET, "build_socks4a_resolve_request failed: %s", errmsg); + *out = NULL; + tor_free(output); + } + return errmsg ? -1 : encoded_len; +} + +#define SOCKS5_ATYPE_HOSTNAME 0x03 +#define SOCKS5_ATYPE_IPV4 0x01 +#define SOCKS5_ATYPE_IPV6 0x04 + +/** + * Set <b>out</b> to pointer to newly allocated buffer containing + * SOCKS5 RESOLVE/RESOLVE_PTR request with given <b>hostname<b>. + * Generate a reverse request if <b>reverse</b> is true. + * Return the number of bytes in the buffer if succeeded or -1 if failed. + */ +static ssize_t +build_socks5_resolve_request(uint8_t **out, + const char *hostname, + int reverse) +{ + const char *errmsg = NULL; + uint8_t *outbuf = NULL; + int is_ip_address; + tor_addr_t addr; + size_t addrlen; + int ipv6; + is_ip_address = tor_addr_parse(&addr, hostname) != -1; + if (!is_ip_address && reverse) { + log_err(LD_GENERAL, "Tried to do a reverse lookup on a non-IP!"); + return -1; + } + ipv6 = reverse && tor_addr_family(&addr) == AF_INET6; + addrlen = reverse ? (ipv6 ? 16 : 4) : 1 + strlen(hostname); + if (addrlen > UINT8_MAX) { + log_err(LD_GENERAL, "Hostname is too long!"); + return -1; + } + + socks5_client_request_t *rq = socks5_client_request_new(); + + socks5_client_request_set_version(rq, 5); + /* RESOLVE_PTR or RESOLVE */ + socks5_client_request_set_command(rq, reverse ? CMD_RESOLVE_PTR : + CMD_RESOLVE); + socks5_client_request_set_reserved(rq, 0); + + uint8_t atype = SOCKS5_ATYPE_HOSTNAME; + if (reverse) + atype = ipv6 ? SOCKS5_ATYPE_IPV6 : SOCKS5_ATYPE_IPV4; + + socks5_client_request_set_atype(rq, atype); + + switch (atype) { + case SOCKS5_ATYPE_IPV4: { + socks5_client_request_set_dest_addr_ipv4(rq, + tor_addr_to_ipv4h(&addr)); + } break; + case SOCKS5_ATYPE_IPV6: { + uint8_t *ipv6_array = + socks5_client_request_getarray_dest_addr_ipv6(rq); + + tor_assert(ipv6_array); + + memcpy(ipv6_array, tor_addr_to_in6_addr8(&addr), 16); + } break; + + case SOCKS5_ATYPE_HOSTNAME: { + domainname_t *dn = domainname_new(); + domainname_set_len(dn, addrlen - 1); + domainname_setlen_name(dn, addrlen - 1); + char *dn_buf = domainname_getarray_name(dn); + memcpy(dn_buf, hostname, addrlen - 1); + + errmsg = domainname_check(dn); + + if (errmsg) { + domainname_free(dn); + goto cleanup; + } else { + socks5_client_request_set_dest_addr_domainname(rq, dn); + } + } break; + default: + tor_assert_unreached(); + break; + } + + socks5_client_request_set_dest_port(rq, 0); + + errmsg = socks5_client_request_check(rq); + if (errmsg) { + goto cleanup; + } + + ssize_t encoded_len = socks5_client_request_encoded_len(rq); + if (encoded_len < 0) { + errmsg = "Cannot predict encoded length"; + goto cleanup; + } + + outbuf = tor_malloc(encoded_len); + memset(outbuf, 0, encoded_len); + + encoded_len = socks5_client_request_encode(outbuf, encoded_len, rq); + if (encoded_len < 0) { + errmsg = "encoding failed"; + goto cleanup; + } + + *out = outbuf; + + cleanup: + socks5_client_request_free(rq); + if (errmsg) { + tor_free(outbuf); + log_err(LD_NET, "build_socks5_resolve_request failed with error: %s", + errmsg); + } + + return errmsg ? -1 : encoded_len; +} + /** Set *<b>out</b> to a newly allocated SOCKS4a resolve request with * <b>username</b> and <b>hostname</b> as provided. Return the number * of bytes in the request. */ static ssize_t -build_socks_resolve_request(char **out, +build_socks_resolve_request(uint8_t **out, const char *username, const char *hostname, int reverse, int version) { - size_t len = 0; tor_assert(out); tor_assert(username); tor_assert(hostname); + tor_assert(version == 4 || version == 5); + if (version == 4) { - len = 8 + strlen(username) + 1 + strlen(hostname) + 1; - *out = tor_malloc(len); - (*out)[0] = 4; /* SOCKS version 4 */ - (*out)[1] = '\xF0'; /* Command: resolve. */ - set_uint16((*out)+2, htons(0)); /* port: 0. */ - set_uint32((*out)+4, htonl(0x00000001u)); /* addr: 0.0.0.1 */ - memcpy((*out)+8, username, strlen(username)+1); - memcpy((*out)+8+strlen(username)+1, hostname, strlen(hostname)+1); + return build_socks4a_resolve_request(out, username, hostname); } else if (version == 5) { - int is_ip_address; - tor_addr_t addr; - size_t addrlen; - int ipv6; - is_ip_address = tor_addr_parse(&addr, hostname) != -1; - if (!is_ip_address && reverse) { - log_err(LD_GENERAL, "Tried to do a reverse lookup on a non-IP!"); - return -1; - } - ipv6 = reverse && tor_addr_family(&addr) == AF_INET6; - addrlen = reverse ? (ipv6 ? 16 : 4) : 1 + strlen(hostname); - if (addrlen > UINT8_MAX) { - log_err(LD_GENERAL, "Hostname is too long!"); - return -1; - } - len = 6 + addrlen; - *out = tor_malloc(len); - (*out)[0] = 5; /* SOCKS version 5 */ - (*out)[1] = reverse ? '\xF1' : '\xF0'; /* RESOLVE_PTR or RESOLVE */ - (*out)[2] = 0; /* reserved. */ - if (reverse) { - (*out)[3] = ipv6 ? 4 : 1; - if (ipv6) - memcpy((*out)+4, tor_addr_to_in6_addr8(&addr), 16); - else - set_uint32((*out)+4, tor_addr_to_ipv4n(&addr)); - } else { - (*out)[3] = 3; - (*out)[4] = (char)(uint8_t)(addrlen - 1); - memcpy((*out)+5, hostname, addrlen - 1); - } - set_uint16((*out)+4+addrlen, 0); /* port */ - } else { - tor_assert(0); + return build_socks5_resolve_request(out, hostname, reverse); } - return len; + tor_assert_unreached(); + return -1; } static void @@ -134,34 +273,50 @@ parse_socks4a_resolve_response(const char *hostname, const char *response, size_t len, tor_addr_t *addr_out) { + int result = 0; uint8_t status; tor_assert(response); tor_assert(addr_out); - if (len < RESPONSE_LEN_4) { + socks4_server_reply_t *reply; + + ssize_t parsed = socks4_server_reply_parse(&reply, + (const uint8_t *)response, + len); + + if (parsed == -1) { + log_warn(LD_PROTOCOL, "Failed parsing SOCKS4a response"); + result = -1; goto cleanup; + } + + if (parsed == -2) { log_warn(LD_PROTOCOL,"Truncated socks response."); - return -1; + result = -1; goto cleanup; } - if (((uint8_t)response[0])!=0) { /* version: 0 */ + + if (socks4_server_reply_get_version(reply) != 0) { /* version: 0 */ log_warn(LD_PROTOCOL,"Nonzero version in socks response: bad format."); - return -1; + result = -1; goto cleanup; } - status = (uint8_t)response[1]; - if (get_uint16(response+2)!=0) { /* port: 0 */ + if (socks4_server_reply_get_port(reply) != 0) { /* port: 0 */ log_warn(LD_PROTOCOL,"Nonzero port in socks response: bad format."); - return -1; + result = -1; goto cleanup; } + status = socks4_server_reply_get_status(reply); if (status != 90) { log_warn(LD_NET,"Got status response '%d': socks request failed.", status); if (!strcasecmpend(hostname, ".onion")) { onion_warning(hostname); - return -1; + result = -1; goto cleanup; } - return -1; + result = -1; goto cleanup; } - tor_addr_from_ipv4n(addr_out, get_uint32(response+4)); - return 0; + tor_addr_from_ipv4h(addr_out, socks4_server_reply_get_addr(reply)); + + cleanup: + socks4_server_reply_free(reply); + return result; } /* It would be nice to let someone know what SOCKS5 issue a user may have */ @@ -205,7 +360,7 @@ do_resolve(const char *hostname, int s = -1; struct sockaddr_storage ss; socklen_t socklen; - char *req = NULL; + uint8_t *req = NULL; ssize_t len = 0; tor_assert(hostname); @@ -230,23 +385,58 @@ do_resolve(const char *hostname, } if (version == 5) { - char method_buf[2]; - if (write_all_to_socket(s, "\x05\x01\x00", 3) != 3) { + socks5_client_version_t *v = socks5_client_version_new(); + + socks5_client_version_set_version(v, 5); + socks5_client_version_set_n_methods(v, 1); + socks5_client_version_setlen_methods(v, 1); + socks5_client_version_set_methods(v, 0, 0x00); + + tor_assert(!socks5_client_version_check(v)); + ssize_t encoded_len = socks5_client_version_encoded_len(v); + tor_assert(encoded_len > 0); + + uint8_t *buf = tor_malloc(encoded_len); + encoded_len = socks5_client_version_encode(buf, encoded_len, v); + tor_assert(encoded_len > 0); + + socks5_client_version_free(v); + + if (write_all_to_socket(s, (const char *)buf, + encoded_len) != encoded_len) { log_err(LD_NET, "Error sending SOCKS5 method list."); + tor_free(buf); + goto err; } - if (read_all_from_socket(s, method_buf, 2) != 2) { + + tor_free(buf); + + uint8_t method_buf[2]; + + if (read_all_from_socket(s, (char *)method_buf, 2) != 2) { log_err(LD_NET, "Error reading SOCKS5 methods."); goto err; } - if (method_buf[0] != '\x05') { - log_err(LD_NET, "Unrecognized socks version: %u", - (unsigned)method_buf[0]); + + socks5_server_method_t *m; + ssize_t parsed = socks5_server_method_parse(&m, method_buf, + sizeof(method_buf)); + + if (parsed < 2) { + log_err(LD_NET, "Failed to parse SOCKS5 method selection " + "message"); + socks5_server_method_free(m); goto err; } - if (method_buf[1] != '\x00') { + + uint8_t method = socks5_server_method_get_method(m); + + socks5_server_method_free(m); + + if (method != 0x00) { log_err(LD_NET, "Unrecognized socks authentication method: %u", - (unsigned)method_buf[1]); + (unsigned)method); goto err; } } @@ -257,7 +447,7 @@ do_resolve(const char *hostname, tor_assert(!req); goto err; } - if (write_all_to_socket(s, req, len) != len) { + if (write_all_to_socket(s, (const char *)req, len) != len) { log_sock_error("sending SOCKS request", s); tor_free(req); goto err; @@ -276,55 +466,59 @@ do_resolve(const char *hostname, goto err; } } else { - char reply_buf[16]; - if (read_all_from_socket(s, reply_buf, 4) != 4) { - log_err(LD_NET, "Error reading SOCKS5 response."); + uint8_t reply_buf[512]; + + len = read_all_from_socket(s, (char *)reply_buf, + sizeof(reply_buf)); + + socks5_server_reply_t *reply; + + ssize_t parsed = socks5_server_reply_parse(&reply, + reply_buf, + len); + if (parsed == -1) { + log_err(LD_NET, "Failed parsing SOCKS5 response"); goto err; } - if (reply_buf[0] != 5) { - log_err(LD_NET, "Bad SOCKS5 reply version."); + + if (parsed == -2) { + log_err(LD_NET, "Truncated SOCKS5 response"); goto err; } + /* Give a user some useful feedback about SOCKS5 errors */ - if (reply_buf[1] != 0) { + uint8_t reply_field = socks5_server_reply_get_reply(reply); + if (reply_field != 0) { log_warn(LD_NET,"Got SOCKS5 status response '%u': %s", - (unsigned)reply_buf[1], - socks5_reason_to_string(reply_buf[1])); - if (reply_buf[1] == 4 && !strcasecmpend(hostname, ".onion")) { + (unsigned)reply_field, + socks5_reason_to_string(reply_field)); + if (reply_field == 4 && !strcasecmpend(hostname, ".onion")) { onion_warning(hostname); } + + socks5_server_reply_free(reply); goto err; } - if (reply_buf[3] == 1) { + + uint8_t atype = socks5_server_reply_get_atype(reply); + + if (atype == SOCKS5_ATYPE_IPV4) { /* IPv4 address */ - if (read_all_from_socket(s, reply_buf, 4) != 4) { - log_err(LD_NET, "Error reading address in socks5 response."); - goto err; - } - tor_addr_from_ipv4n(result_addr, get_uint32(reply_buf)); - } else if (reply_buf[3] == 4) { + tor_addr_from_ipv4h(result_addr, + socks5_server_reply_get_bind_addr_ipv4(reply)); + } else if (atype == SOCKS5_ATYPE_IPV6) { /* IPv6 address */ - if (read_all_from_socket(s, reply_buf, 16) != 16) { - log_err(LD_NET, "Error reading address in socks5 response."); - goto err; - } - tor_addr_from_ipv6_bytes(result_addr, reply_buf); - } else if (reply_buf[3] == 3) { + tor_addr_from_ipv6_bytes(result_addr, + socks5_server_reply_getarray_bind_addr_ipv6(reply)); + } else if (atype == SOCKS5_ATYPE_HOSTNAME) { /* Domain name */ - size_t result_len; - if (read_all_from_socket(s, reply_buf, 1) != 1) { - log_err(LD_NET, "Error reading address_length in socks5 response."); - goto err; - } - result_len = *(uint8_t*)(reply_buf); - *result_hostname = tor_malloc(result_len+1); - if (read_all_from_socket(s, *result_hostname, result_len) - != (int) result_len) { - log_err(LD_NET, "Error reading hostname in socks5 response."); - goto err; - } - (*result_hostname)[result_len] = '\0'; + domainname_t *dn = + socks5_server_reply_get_bind_addr_domainname(reply); + + *result_hostname = tor_strdup(domainname_getstr_name(dn)); } + + socks5_server_reply_free(reply); } tor_close_socket(s); |