| /*************************************************************************** |
| * _ _ ____ _ |
| * Project ___| | | | _ \| | |
| * / __| | | | |_) | | |
| * | (__| |_| | _ <| |___ |
| * \___|\___/|_| \_\_____| |
| * |
| * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. |
| * Copyright (C) Markus Moeller, <markus_moeller@compuserve.com> |
| * |
| * 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. |
| * |
| * SPDX-License-Identifier: curl |
| * |
| ***************************************************************************/ |
| #include "curl_setup.h" |
| |
| #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_PROXY) |
| |
| #include "curl_gssapi.h" |
| #include "urldata.h" |
| #include "curl_trc.h" |
| #include "cfilters.h" |
| #include "connect.h" |
| #include "curlx/nonblock.h" |
| #include "socks.h" |
| #include "strdup.h" |
| |
| #if defined(__GNUC__) && defined(__APPLE__) |
| #pragma GCC diagnostic push |
| #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
| #endif |
| |
| #define MAX_GSS_LEN 1024 |
| |
| /* |
| * Helper GSS-API error functions. |
| */ |
| static int check_gss_err(struct Curl_easy *data, |
| OM_uint32 major_status, |
| OM_uint32 minor_status, |
| const char *function) |
| { |
| if(GSS_ERROR(major_status)) { |
| OM_uint32 maj_stat, min_stat; |
| OM_uint32 msg_ctx = 0; |
| gss_buffer_desc status_string = GSS_C_EMPTY_BUFFER; |
| struct dynbuf dbuf; |
| |
| curlx_dyn_init(&dbuf, MAX_GSS_LEN); |
| msg_ctx = 0; |
| while(!msg_ctx) { |
| /* convert major status code (GSS-API error) to text */ |
| maj_stat = gss_display_status(&min_stat, major_status, |
| GSS_C_GSS_CODE, |
| GSS_C_NULL_OID, |
| &msg_ctx, &status_string); |
| if(maj_stat == GSS_S_COMPLETE) { |
| if(curlx_dyn_addn(&dbuf, status_string.value, status_string.length)) |
| return 1; /* error */ |
| gss_release_buffer(&min_stat, &status_string); |
| break; |
| } |
| gss_release_buffer(&min_stat, &status_string); |
| } |
| if(curlx_dyn_addn(&dbuf, ".\n", 2)) |
| return 1; /* error */ |
| msg_ctx = 0; |
| while(!msg_ctx) { |
| /* convert minor status code (underlying routine error) to text */ |
| maj_stat = gss_display_status(&min_stat, minor_status, |
| GSS_C_MECH_CODE, |
| GSS_C_NULL_OID, |
| &msg_ctx, &status_string); |
| if(maj_stat == GSS_S_COMPLETE) { |
| if(curlx_dyn_addn(&dbuf, status_string.value, status_string.length)) |
| return 1; /* error */ |
| gss_release_buffer(&min_stat, &status_string); |
| break; |
| } |
| gss_release_buffer(&min_stat, &status_string); |
| } |
| failf(data, "GSS-API error: %s failed: %s", function, |
| curlx_dyn_ptr(&dbuf)); |
| curlx_dyn_free(&dbuf); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf, |
| struct Curl_easy *data) |
| { |
| struct connectdata *conn = cf->conn; |
| curl_socket_t sock = conn->sock[cf->sockindex]; |
| CURLcode code; |
| size_t actualread; |
| size_t nwritten; |
| int result; |
| OM_uint32 gss_major_status, gss_minor_status, gss_status; |
| OM_uint32 gss_ret_flags; |
| int gss_conf_state, gss_enc; |
| gss_buffer_desc service = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc gss_send_token = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc gss_recv_token = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc gss_w_token = GSS_C_EMPTY_BUFFER; |
| gss_buffer_desc *gss_token = GSS_C_NO_BUFFER; |
| gss_name_t server = GSS_C_NO_NAME; |
| gss_name_t gss_client_name = GSS_C_NO_NAME; |
| unsigned short us_length; |
| unsigned char socksreq[4]; /* room for GSS-API exchange header only */ |
| const char *serviceptr = data->set.str[STRING_PROXY_SERVICE_NAME] ? |
| data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd"; |
| const size_t serviceptr_length = strlen(serviceptr); |
| gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT; |
| |
| /* GSS-API request looks like |
| * +----+------+-----+----------------+ |
| * |VER | MTYP | LEN | TOKEN | |
| * +----+------+----------------------+ |
| * | 1 | 1 | 2 | up to 2^16 - 1 | |
| * +----+------+-----+----------------+ |
| */ |
| |
| /* prepare service name */ |
| if(strchr(serviceptr, '/')) { |
| service.length = serviceptr_length; |
| service.value = Curl_memdup(serviceptr, service.length); |
| if(!service.value) |
| return CURLE_OUT_OF_MEMORY; |
| |
| gss_major_status = gss_import_name(&gss_minor_status, &service, |
| (gss_OID)GSS_C_NULL_OID, &server); |
| } |
| else { |
| service.value = curlx_malloc(serviceptr_length + |
| strlen(conn->socks_proxy.host.name) + 2); |
| if(!service.value) |
| return CURLE_OUT_OF_MEMORY; |
| service.length = serviceptr_length + |
| strlen(conn->socks_proxy.host.name) + 1; |
| curl_msnprintf(service.value, service.length + 1, "%s@%s", |
| serviceptr, conn->socks_proxy.host.name); |
| |
| gss_major_status = gss_import_name(&gss_minor_status, &service, |
| GSS_C_NT_HOSTBASED_SERVICE, &server); |
| } |
| |
| Curl_safefree(service.value); |
| service.length = 0; |
| |
| if(check_gss_err(data, gss_major_status, |
| gss_minor_status, "gss_import_name()")) { |
| failf(data, "Failed to create service name."); |
| gss_release_name(&gss_status, &server); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| (void)curlx_nonblock(sock, FALSE); |
| |
| /* As long as we need to keep sending some context info, and there is no */ |
| /* errors, keep sending it... */ |
| for(;;) { |
| gss_major_status = Curl_gss_init_sec_context(data, |
| &gss_minor_status, |
| &gss_context, |
| server, |
| &Curl_krb5_mech_oid, |
| NULL, |
| gss_token, |
| &gss_send_token, |
| TRUE, |
| &gss_ret_flags); |
| |
| if(gss_token != GSS_C_NO_BUFFER) { |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| } |
| if(check_gss_err(data, gss_major_status, |
| gss_minor_status, "gss_init_sec_context") || |
| /* the size needs to fit in a 16 bit field */ |
| (gss_send_token.length > 0xffff)) { |
| gss_release_name(&gss_status, &server); |
| gss_release_buffer(&gss_status, &gss_send_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| failf(data, "Failed to initial GSS-API token."); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| if(gss_send_token.length) { |
| socksreq[0] = 1; /* GSS-API subnegotiation version */ |
| socksreq[1] = 1; /* authentication message type */ |
| us_length = htons((unsigned short)gss_send_token.length); |
| memcpy(socksreq + 2, &us_length, sizeof(short)); |
| |
| code = Curl_conn_cf_send(cf->next, data, socksreq, 4, FALSE, &nwritten); |
| if(code || (nwritten != 4)) { |
| failf(data, "Failed to send GSS-API authentication request."); |
| gss_release_name(&gss_status, &server); |
| gss_release_buffer(&gss_status, &gss_send_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| code = Curl_conn_cf_send(cf->next, data, |
| gss_send_token.value, |
| gss_send_token.length, FALSE, &nwritten); |
| if(code || (gss_send_token.length != nwritten)) { |
| failf(data, "Failed to send GSS-API authentication token."); |
| gss_release_name(&gss_status, &server); |
| gss_release_buffer(&gss_status, &gss_send_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| } |
| |
| gss_release_buffer(&gss_status, &gss_send_token); |
| if(gss_major_status != GSS_S_CONTINUE_NEEDED) |
| break; |
| |
| /* analyse response */ |
| |
| /* GSS-API response looks like |
| * +----+------+-----+----------------+ |
| * |VER | MTYP | LEN | TOKEN | |
| * +----+------+----------------------+ |
| * | 1 | 1 | 2 | up to 2^16 - 1 | |
| * +----+------+-----+----------------+ |
| */ |
| |
| result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread); |
| if(result || (actualread != 4)) { |
| failf(data, "Failed to receive GSS-API authentication response."); |
| gss_release_name(&gss_status, &server); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| /* ignore the first (VER) byte */ |
| if(socksreq[1] == 255) { /* status / message type */ |
| failf(data, "User was rejected by the SOCKS5 server (%d %d).", |
| socksreq[0], socksreq[1]); |
| gss_release_name(&gss_status, &server); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| if(socksreq[1] != 1) { /* status / message type */ |
| failf(data, "Invalid GSS-API authentication response type (%d %d).", |
| socksreq[0], socksreq[1]); |
| gss_release_name(&gss_status, &server); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| memcpy(&us_length, socksreq + 2, sizeof(short)); |
| us_length = ntohs(us_length); |
| |
| gss_recv_token.length = us_length; |
| gss_recv_token.value = curlx_malloc(gss_recv_token.length); |
| if(!gss_recv_token.value) { |
| failf(data, |
| "Could not allocate memory for GSS-API authentication " |
| "response token."); |
| gss_release_name(&gss_status, &server); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_OUT_OF_MEMORY; |
| } |
| |
| result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value, |
| gss_recv_token.length, &actualread); |
| |
| if(result || (actualread != us_length)) { |
| failf(data, "Failed to receive GSS-API authentication token."); |
| gss_release_name(&gss_status, &server); |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| gss_token = &gss_recv_token; |
| } |
| |
| gss_release_name(&gss_status, &server); |
| |
| /* Everything is good so far, user was authenticated! */ |
| gss_major_status = gss_inquire_context(&gss_minor_status, gss_context, |
| &gss_client_name, NULL, NULL, NULL, |
| NULL, NULL, NULL); |
| if(check_gss_err(data, gss_major_status, |
| gss_minor_status, "gss_inquire_context")) { |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| gss_release_name(&gss_status, &gss_client_name); |
| failf(data, "Failed to determine username."); |
| return CURLE_COULDNT_CONNECT; |
| } |
| gss_major_status = gss_display_name(&gss_minor_status, gss_client_name, |
| &gss_send_token, NULL); |
| if(check_gss_err(data, gss_major_status, |
| gss_minor_status, "gss_display_name")) { |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| gss_release_name(&gss_status, &gss_client_name); |
| gss_release_buffer(&gss_status, &gss_send_token); |
| failf(data, "Failed to determine username."); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| infof(data, "SOCKS5 server authenticated user %.*s with GSS-API.", |
| (int)gss_send_token.length, (char *)gss_send_token.value); |
| |
| gss_release_name(&gss_status, &gss_client_name); |
| gss_release_buffer(&gss_status, &gss_send_token); |
| |
| /* Do encryption */ |
| socksreq[0] = 1; /* GSS-API subnegotiation version */ |
| socksreq[1] = 2; /* encryption message type */ |
| |
| gss_enc = 0; /* no data protection */ |
| /* do confidentiality protection if supported */ |
| if(gss_ret_flags & GSS_C_CONF_FLAG) |
| gss_enc = 2; |
| /* else do integrity protection */ |
| else if(gss_ret_flags & GSS_C_INTEG_FLAG) |
| gss_enc = 1; |
| |
| infof(data, "SOCKS5 server supports GSS-API %s data protection.", |
| (gss_enc == 0) ? "no" : |
| ((gss_enc == 1) ? "integrity" : "confidentiality")); |
| |
| /* |
| * Sending the encryption type in clear seems wrong. It should be |
| * protected with gss_seal()/gss_wrap(). See RFC1961 extract below |
| * The NEC reference implementations on which this is based is |
| * therefore at fault |
| * |
| * +------+------+------+.......................+ |
| * + ver | mtyp | len | token | |
| * +------+------+------+.......................+ |
| * + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets | |
| * +------+------+------+.......................+ |
| * |
| * Where: |
| * |
| * - "ver" is the protocol version number, here 1 to represent the |
| * first version of the SOCKS/GSS-API protocol |
| * |
| * - "mtyp" is the message type, here 2 to represent a protection |
| * -level negotiation message |
| * |
| * - "len" is the length of the "token" field in octets |
| * |
| * - "token" is the GSS-API encapsulated protection level |
| * |
| * The token is produced by encapsulating an octet containing the |
| * required protection level using gss_seal()/gss_wrap() with conf_req |
| * set to FALSE. The token is verified using gss_unseal()/ |
| * gss_unwrap(). |
| * |
| */ |
| if(data->set.socks5_gssapi_nec) { |
| us_length = htons((short)1); |
| memcpy(socksreq + 2, &us_length, sizeof(short)); |
| } |
| else { |
| gss_send_token.length = 1; |
| gss_send_token.value = Curl_memdup(&gss_enc, gss_send_token.length); |
| if(!gss_send_token.value) { |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_OUT_OF_MEMORY; |
| } |
| |
| gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0, |
| GSS_C_QOP_DEFAULT, &gss_send_token, |
| &gss_conf_state, &gss_w_token); |
| |
| if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) { |
| Curl_safefree(gss_send_token.value); |
| gss_send_token.length = 0; |
| gss_release_buffer(&gss_status, &gss_w_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| failf(data, "Failed to wrap GSS-API encryption value into token."); |
| return CURLE_COULDNT_CONNECT; |
| } |
| Curl_safefree(gss_send_token.value); |
| gss_send_token.length = 0; |
| |
| us_length = htons((unsigned short)gss_w_token.length); |
| memcpy(socksreq + 2, &us_length, sizeof(short)); |
| } |
| |
| code = Curl_conn_cf_send(cf->next, data, socksreq, 4, FALSE, &nwritten); |
| if(code || (nwritten != 4)) { |
| failf(data, "Failed to send GSS-API encryption request."); |
| gss_release_buffer(&gss_status, &gss_w_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| if(data->set.socks5_gssapi_nec) { |
| memcpy(socksreq, &gss_enc, 1); |
| code = Curl_conn_cf_send(cf->next, data, socksreq, 1, FALSE, &nwritten); |
| if(code || (nwritten != 1)) { |
| failf(data, "Failed to send GSS-API encryption type."); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| } |
| else { |
| code = Curl_conn_cf_send(cf->next, data, gss_w_token.value, |
| gss_w_token.length, FALSE, &nwritten); |
| if(code || (gss_w_token.length != nwritten)) { |
| failf(data, "Failed to send GSS-API encryption type."); |
| gss_release_buffer(&gss_status, &gss_w_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| gss_release_buffer(&gss_status, &gss_w_token); |
| } |
| |
| result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread); |
| if(result || (actualread != 4)) { |
| failf(data, "Failed to receive GSS-API encryption response."); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| /* ignore the first (VER) byte */ |
| if(socksreq[1] == 255) { /* status / message type */ |
| failf(data, "User was rejected by the SOCKS5 server (%d %d).", |
| socksreq[0], socksreq[1]); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| if(socksreq[1] != 2) { /* status / message type */ |
| failf(data, "Invalid GSS-API encryption response type (%d %d).", |
| socksreq[0], socksreq[1]); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| memcpy(&us_length, socksreq + 2, sizeof(short)); |
| us_length = ntohs(us_length); |
| |
| gss_recv_token.length = us_length; |
| gss_recv_token.value = curlx_malloc(gss_recv_token.length); |
| if(!gss_recv_token.value) { |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_OUT_OF_MEMORY; |
| } |
| result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value, |
| gss_recv_token.length, &actualread); |
| |
| if(result || (actualread != us_length)) { |
| failf(data, "Failed to receive GSS-API encryption type."); |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| if(!data->set.socks5_gssapi_nec) { |
| gss_major_status = gss_unwrap(&gss_minor_status, gss_context, |
| &gss_recv_token, &gss_w_token, |
| 0, GSS_C_QOP_DEFAULT); |
| |
| if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) { |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| gss_release_buffer(&gss_status, &gss_w_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| failf(data, "Failed to unwrap GSS-API encryption value into token."); |
| return CURLE_COULDNT_CONNECT; |
| } |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| |
| if(gss_w_token.length != 1) { |
| failf(data, "Invalid GSS-API encryption response length (%zu).", |
| gss_w_token.length); |
| gss_release_buffer(&gss_status, &gss_w_token); |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| memcpy(socksreq, gss_w_token.value, gss_w_token.length); |
| gss_release_buffer(&gss_status, &gss_w_token); |
| } |
| else { |
| if(gss_recv_token.length != 1) { |
| failf(data, "Invalid GSS-API encryption response length (%zu).", |
| gss_recv_token.length); |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| return CURLE_COULDNT_CONNECT; |
| } |
| |
| memcpy(socksreq, gss_recv_token.value, gss_recv_token.length); |
| Curl_safefree(gss_recv_token.value); |
| gss_recv_token.length = 0; |
| } |
| |
| (void)curlx_nonblock(sock, TRUE); |
| |
| infof(data, "SOCKS5 access with%s protection granted.", |
| (socksreq[0] == 0) ? "out GSS-API data": |
| ((socksreq[0] == 1) ? " GSS-API integrity" : |
| " GSS-API confidentiality")); |
| |
| conn->socks5_gssapi_enctype = socksreq[0]; |
| if(socksreq[0] == 0) |
| Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL); |
| |
| return CURLE_OK; |
| } |
| |
| #if defined(__GNUC__) && defined(__APPLE__) |
| #pragma GCC diagnostic pop |
| #endif |
| |
| #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */ |
