commit 83af6d6149bb589be01a14b1d800614c1beb9f18 Author: rl1987 rl1987@sdf.lonestar.org Date: Tue Sep 11 21:42:38 2018 +0300

tor-resolve: Use trunnel code for SOCKS5 request generation --- src/tools/tor-resolve.c | 158 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 122 insertions(+), 36 deletions(-)

diff --git a/src/tools/tor-resolve.c b/src/tools/tor-resolve.c index 4ba372b66..c255a7112 100644 --- a/src/tools/tor-resolve.c +++ b/src/tools/tor-resolve.c @@ -107,6 +107,123 @@ build_socks4a_resolve_request(uint8_t **out, 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. */ @@ -117,51 +234,20 @@ build_socks_resolve_request(uint8_t **out, 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) { 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