/*************************************************************************** * ncat_connect.c -- Ncat connect mode. * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2015 Insecure.Com LLC. Nmap is * * also a registered trademark of Insecure.Com LLC. This program is free * * software; you may redistribute and/or modify it under the terms of the * * GNU General Public License as published by the Free Software * * Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE CLARIFICATIONS * * AND EXCEPTIONS DESCRIBED HEREIN. This guarantees your right to use, * * modify, and redistribute this software under certain conditions. If * * you wish to embed Nmap technology into proprietary software, we sell * * alternative licenses (contact sales@nmap.com). Dozens of software * * vendors already license Nmap technology such as host discovery, port * * scanning, OS detection, version detection, and the Nmap Scripting * * Engine. * * * * Note that the GPL places important restrictions on "derivative works", * * yet it does not provide a detailed definition of that term. To avoid * * misunderstandings, we interpret that term as broadly as copyright law * * allows. For example, we consider an application to constitute a * * derivative work for the purpose of this license if it does any of the * * following with any software or content covered by this license * * ("Covered Software"): * * * * o Integrates source code from Covered Software. * * * * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db * * or nmap-service-probes. * * * * o Is designed specifically to execute Covered Software and parse the * * results (as opposed to typical shell or execution-menu apps, which will * * execute anything you tell them to). * * * * o Includes Covered Software in a proprietary executable installer. The * * installers produced by InstallShield are an example of this. Including * * Nmap with other software in compressed or archival form does not * * trigger this provision, provided appropriate open source decompression * * or de-archiving software is widely available for no charge. For the * * purposes of this license, an installer is considered to include Covered * * Software even if it actually retrieves a copy of Covered Software from * * another source during runtime (such as by downloading it from the * * Internet). * * * * o Links (statically or dynamically) to a library which does any of the * * above. * * * * o Executes a helper program, module, or script to do any of the above. * * * * This list is not exclusive, but is meant to clarify our interpretation * * of derived works with some common examples. Other people may interpret * * the plain GPL differently, so we consider this a special exception to * * the GPL that we apply to Covered Software. Works which meet any of * * these conditions must conform to all of the terms of this license, * * particularly including the GPL Section 3 requirements of providing * * source code and allowing free redistribution of the work as a whole. * * * * As another special exception to the GPL terms, Insecure.Com LLC grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. * * * * Any redistribution of Covered Software, including any derived works, * * must obey and carry forward all of the terms of this license, including * * obeying all GPL rules and restrictions. For example, source code of * * the whole work must be provided and free redistribution must be * * allowed. All GPL references to "this License", are to be treated as * * including the terms and conditions of this license text as well. * * * * Because this license imposes special exceptions to the GPL, Covered * * Work may not be combined (even as part of a larger work) with plain GPL * * software. The terms, conditions, and exceptions of this license must * * be included as well. This license is incompatible with some other open * * source licenses as well. In some cases we can relicense portions of * * Nmap or grant special permissions to use it in other open source * * software. Please contact fyodor@nmap.org with any such requests. * * Similarly, we don't incorporate incompatible open source software into * * Covered Software without special permission from the copyright holders. * * * * If you have any questions about the licensing restrictions on using * * Nmap in other works, are happy to help. As mentioned above, we also * * offer alternative license to integrate Nmap into proprietary * * applications and appliances. These contracts have been sold to dozens * * of software vendors, and generally include a perpetual license as well * * as providing for priority support and updates. They also fund the * * continued development of Nmap. Please email sales@nmap.com for further * * information. * * * * If you have received a written license agreement or contract for * * Covered Software stating terms other than these, you may choose to use * * and redistribute Covered Software under those terms instead of these. * * * * Source is provided to this software because we believe users have a * * right to know exactly what a program is going to do before they run it. * * This also allows you to audit the software for security holes. * * * * Source code also allows you to port Nmap to new platforms, fix bugs, * * and add new features. You are highly encouraged to send your changes * * to the dev@nmap.org mailing list for possible incorporation into the * * main distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, or checking them into the Nmap * * source code repository, it is understood (unless you specify otherwise) * * that you are offering the Nmap Project (Insecure.Com LLC) the * * unlimited, non-exclusive right to reuse, modify, and relicense the * * code. Nmap will always be available Open Source, but this is important * * because the inability to relicense code has caused devastating problems * * for other Free Software projects (such as KDE and NASM). We also * * occasionally relicense the code to third parties as discussed above. * * If you wish to specify special license conditions of your * * contributions, just say so when you send them. * * * * This program is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap * * license file for more details (it's in a COPYING file included with * * Nmap, and also available from https://svn.nmap.org/nmap/COPYING) * * * ***************************************************************************/ /* $Id$ */ #include "base64.h" #include "nsock.h" #include "ncat.h" #include "util.h" #include "sys_wrap.h" #include "nbase.h" #include "http.h" #ifndef WIN32 #include #include #endif #include #include #include #ifdef HAVE_OPENSSL #include #include #endif #ifdef WIN32 /* Define missing constant for shutdown(2). * See: * http://msdn.microsoft.com/en-us/library/windows/desktop/ms740481%28v=vs.85%29.aspx */ #define SHUT_WR SD_SEND #endif struct conn_state { nsock_iod sock_nsi; nsock_iod stdin_nsi; nsock_event_id idle_timer_event_id; int crlf_state; }; static struct conn_state cs = { NULL, NULL, 0, 0 }; static void connect_handler(nsock_pool nsp, nsock_event evt, void *data); static void post_connect(nsock_pool nsp, nsock_iod iod); static void read_stdin_handler(nsock_pool nsp, nsock_event evt, void *data); static void read_socket_handler(nsock_pool nsp, nsock_event evt, void *data); static void write_socket_handler(nsock_pool nsp, nsock_event evt, void *data); static void idle_timer_handler(nsock_pool nsp, nsock_event evt, void *data); static void refresh_idle_timer(nsock_pool nsp); #ifdef HAVE_OPENSSL /* This callback is called for every certificate in a chain. ok is true if OpenSSL's internal verification has verified the certificate. We don't change anything about the verification, we only need access to the certificates to provide diagnostics. */ static int verify_callback(int ok, X509_STORE_CTX *store) { X509 *cert = X509_STORE_CTX_get_current_cert(store); int err = X509_STORE_CTX_get_error(store); /* Print the subject, issuer, and fingerprint depending on the verbosity level. */ if ((!ok && o.verbose) || o.debug > 1) { char digest_buf[SHA1_STRING_LENGTH + 1]; char *fp; loguser("Subject: "); X509_NAME_print_ex_fp(stderr, X509_get_subject_name(cert), 0, XN_FLAG_COMPAT); loguser_noprefix("\n"); loguser("Issuer: "); X509_NAME_print_ex_fp(stderr, X509_get_issuer_name(cert), 0, XN_FLAG_COMPAT); loguser_noprefix("\n"); fp = ssl_cert_fp_str_sha1(cert, digest_buf, sizeof(digest_buf)); ncat_assert(fp == digest_buf); loguser("SHA-1 fingerprint: %s\n", digest_buf); } if (!ok && o.verbose) { loguser("Certificate verification failed (%s).\n", X509_verify_cert_error_string(err)); } return ok; } static void set_ssl_ctx_options(SSL_CTX *ctx) { if (o.ssltrustfile == NULL) { ssl_load_default_ca_certs(ctx); } else { if (o.debug) logdebug("Using trusted CA certificates from %s.\n", o.ssltrustfile); if (SSL_CTX_load_verify_locations(ctx, o.ssltrustfile, NULL) != 1) { bye("Could not load trusted certificates from %s.\n%s", o.ssltrustfile, ERR_error_string(ERR_get_error(), NULL)); } } if (o.sslverify) { SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, verify_callback); } else { /* Still check verification status and report it */ SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, verify_callback); if (o.ssl && o.debug) logdebug("Not doing certificate verification.\n"); } if (o.sslcert != NULL && o.sslkey != NULL) { if (SSL_CTX_use_certificate_file(ctx, o.sslcert, SSL_FILETYPE_PEM) != 1) bye("SSL_CTX_use_certificate_file(): %s.", ERR_error_string(ERR_get_error(), NULL)); if (SSL_CTX_use_PrivateKey_file(ctx, o.sslkey, SSL_FILETYPE_PEM) != 1) bye("SSL_CTX_use_Privatekey_file(): %s.", ERR_error_string(ERR_get_error(), NULL)); } else { if ((o.sslcert == NULL) != (o.sslkey == NULL)) bye("The --ssl-key and --ssl-cert options must be used together."); } } #endif /* Depending on verbosity, print a message that a connection was established. */ static void connect_report(nsock_iod nsi) { union sockaddr_u peer; zmem(&peer, sizeof(peer.storage)); nsock_iod_get_communication_info(nsi, NULL, NULL, NULL, &peer.sockaddr, sizeof(peer.storage)); if (o.verbose) { #ifdef HAVE_OPENSSL if (nsock_iod_check_ssl(nsi)) { X509 *cert; X509_NAME *subject; char digest_buf[SHA1_STRING_LENGTH + 1]; char *fp; loguser("SSL connection to %s:%hu.", inet_socktop(&peer), nsock_iod_get_peerport(nsi)); cert = SSL_get_peer_certificate((SSL *)nsock_iod_get_ssl(nsi)); ncat_assert(cert != NULL); subject = X509_get_subject_name(cert); if (subject != NULL) { char buf[256]; int n; n = X509_NAME_get_text_by_NID(subject, NID_organizationName, buf, sizeof(buf)); if (n >= 0 && n <= sizeof(buf) - 1) loguser_noprefix(" %s", buf); } loguser_noprefix("\n"); fp = ssl_cert_fp_str_sha1(cert, digest_buf, sizeof(digest_buf)); ncat_assert(fp == digest_buf); loguser("SHA-1 fingerprint: %s\n", digest_buf); } else { #if HAVE_SYS_UN_H if (peer.sockaddr.sa_family == AF_UNIX) loguser("Connected to %s.\n", peer.un.sun_path); else #endif loguser("Connected to %s:%hu.\n", inet_socktop(&peer), nsock_iod_get_peerport(nsi)); } #else #if HAVE_SYS_UN_H if (peer.sockaddr.sa_family == AF_UNIX) loguser("Connected to %s.\n", peer.un.sun_path); else #endif loguser("Connected to %s:%hu.\n", inet_socktop(&peer), nsock_iod_get_peerport(nsi)); #endif } } /* Just like inet_socktop, but it puts IPv6 addresses in square brackets. */ static const char *sock_to_url(char *host_str, unsigned short port) { static char buf[512]; switch(getaddrfamily(host_str)) { case -1: case 1: Snprintf(buf, sizeof(buf), "%s:%hu", host_str, port); break; case 2: Snprintf(buf, sizeof(buf), "[%s]:%hu]", host_str, port); } return buf; } static int append_connect_request_line(char **buf, size_t *size, size_t *offset, char* host_str,unsigned short port) { return strbuf_sprintf(buf, size, offset, "CONNECT %s HTTP/1.0\r\n", sock_to_url(host_str,port)); } static char *http_connect_request(char* host_str, unsigned short port, int *n) { char *buf = NULL; size_t size = 0, offset = 0; append_connect_request_line(&buf, &size, &offset, host_str, port); strbuf_append_str(&buf, &size, &offset, "\r\n"); *n = offset; return buf; } static char *http_connect_request_auth(char* host_str, unsigned short port, int *n, struct http_challenge *challenge) { char *buf = NULL; size_t size = 0, offset = 0; append_connect_request_line(&buf, &size, &offset, host_str, port); strbuf_append_str(&buf, &size, &offset, "Proxy-Authorization:"); if (challenge->scheme == AUTH_BASIC) { char *auth_str; auth_str = b64enc((unsigned char *) o.proxy_auth, strlen(o.proxy_auth)); strbuf_sprintf(&buf, &size, &offset, " Basic %s\r\n", auth_str); free(auth_str); #if HAVE_HTTP_DIGEST } else if (challenge->scheme == AUTH_DIGEST) { char *proxy_auth; char *username, *password; char *response_hdr; /* Split up the proxy auth argument. */ proxy_auth = Strdup(o.proxy_auth); username = strtok(proxy_auth, ":"); password = strtok(NULL, ":"); if (password == NULL) { free(proxy_auth); return NULL; } response_hdr = http_digest_proxy_authorization(challenge, username, password, "CONNECT", sock_to_url(o.target,o.portno)); if (response_hdr == NULL) { free(proxy_auth); return NULL; } strbuf_append_str(&buf, &size, &offset, response_hdr); free(proxy_auth); free(response_hdr); #endif } else { bye("Unknown authentication type."); } strbuf_append_str(&buf, &size, &offset, "\r\n"); *n = offset; return buf; } /* Return a usable socket descriptor after proxy negotiation, or -1 on any error. If any bytes are received through the proxy after negotiation, they are written to stdout. */ static int do_proxy_http(void) { struct socket_buffer sockbuf; char *request; char *status_line, *header; char *remainder; size_t len; int sd, code; int n; sd = do_connect(SOCK_STREAM); if (sd == -1) { loguser("Proxy connection failed: %s.\n", socket_strerror(socket_errno())); return -1; } status_line = NULL; header = NULL; /* First try a request with no authentication. */ request = http_connect_request(o.target,o.portno, &n); if (send(sd, request, n, 0) < 0) { loguser("Error sending proxy request: %s.\n", socket_strerror(socket_errno())); free(request); return -1; } free(request); socket_buffer_init(&sockbuf, sd); if (http_read_status_line(&sockbuf, &status_line) != 0) { loguser("Error reading proxy response Status-Line.\n"); goto bail; } code = http_parse_status_line_code(status_line); if (o.debug) logdebug("Proxy returned status code %d.\n", code); free(status_line); status_line = NULL; if (http_read_header(&sockbuf, &header) != 0) { loguser("Error reading proxy response header.\n"); goto bail; } if (code == 407 && o.proxy_auth != NULL) { struct http_header *h; struct http_challenge challenge; close(sd); sd = -1; if (http_parse_header(&h, header) != 0) { loguser("Error parsing proxy response header.\n"); goto bail; } free(header); header = NULL; if (http_header_get_proxy_challenge(h, &challenge) == NULL) { loguser("Error getting Proxy-Authenticate challenge.\n"); http_header_free(h); goto bail; } http_header_free(h); sd = do_connect(SOCK_STREAM); if (sd == -1) { loguser("Proxy reconnection failed: %s.\n", socket_strerror(socket_errno())); goto bail; } request = http_connect_request_auth(o.target,o.portno, &n, &challenge); if (request == NULL) { loguser("Error building Proxy-Authorization header.\n"); http_challenge_free(&challenge); goto bail; } if (o.debug) logdebug("Reconnection header:\n%s", request); if (send(sd, request, n, 0) < 0) { loguser("Error sending proxy request: %s.\n", socket_strerror(socket_errno())); free(request); http_challenge_free(&challenge); goto bail; } free(request); http_challenge_free(&challenge); socket_buffer_init(&sockbuf, sd); if (http_read_status_line(&sockbuf, &status_line) != 0) { loguser("Error reading proxy response Status-Line.\n"); goto bail; } code = http_parse_status_line_code(status_line); if (o.debug) logdebug("Proxy returned status code %d.\n", code); free(status_line); status_line = NULL; if (http_read_header(&sockbuf, &header) != 0) { loguser("Error reading proxy response header.\n"); goto bail; } } free(header); header = NULL; if (code != 200) { loguser("Proxy returned status code %d.\n", code); return -1; } remainder = socket_buffer_remainder(&sockbuf, &len); Write(STDOUT_FILENO, remainder, len); return sd; bail: if (sd != -1) close(sd); if (status_line != NULL) free(status_line); if (header != NULL) free(header); return -1; } /* SOCKS4a support * Return a usable socket descriptor after * proxy negotiation, or -1 on any error. */ static int do_proxy_socks4(void) { struct socket_buffer stateful_buf; struct socks4_data socks4msg; char socksbuf[8]; int sd,len = 9; sd = do_connect(SOCK_STREAM); if (sd == -1) { loguser("Proxy connection failed: %s.\n", socket_strerror(socket_errno())); return sd; } socket_buffer_init(&stateful_buf, sd); if (o.verbose) { loguser("Connected to proxy %s:%hu\n", inet_socktop(&targetss), inet_port(&targetss)); } /* Fill the socks4_data struct */ zmem(&socks4msg, sizeof(socks4msg)); socks4msg.version = SOCKS4_VERSION; socks4msg.type = SOCKS_CONNECT; socks4msg.port = htons(o.portno); switch(getaddrfamily(o.target)) { case 1: // IPv4 address family socks4msg.address = inet_addr(o.target); if (o.proxy_auth){ memcpy(socks4msg.data, o.proxy_auth, strlen(o.proxy_auth)); len += strlen(o.proxy_auth); } break; case 2: // IPv6 address family loguser("Error: IPv6 addresses are not supported with Socks4.\n"); close(sd); return -1; case -1: // fqdn socks4msg.address = inet_addr("0.0.0.1"); if (strlen(o.target) > SOCKS_BUFF_SIZE-2) { loguser("Error: host name is too long.\n"); close(sd); return -1; } if (o.proxy_auth){ if (strlen(o.target)+strlen(o.proxy_auth) > SOCKS_BUFF_SIZE-2) { loguser("Error: host name and username are too long.\n"); close(sd); return -1; } Strncpy(socks4msg.data,o.proxy_auth,sizeof(socks4msg.data)); len += strlen(o.proxy_auth); } memcpy(socks4msg.data+(len-8), o.target, strlen(o.target)); len += strlen(o.target)+1; } if (send(sd, (char *) &socks4msg, len, 0) < 0) { loguser("Error: sending proxy request: %s.\n", socket_strerror(socket_errno())); close(sd); return -1; } /* The size of the socks4 response is 8 bytes. So read exactly 8 bytes from the buffer */ if (socket_buffer_readcount(&stateful_buf, socksbuf, 8) < 0) { loguser("Error: short response from proxy.\n"); close(sd); return -1; } if (sd != -1 && socksbuf[1] != SOCKS4_CONN_ACC) { loguser("Proxy connection failed.\n"); close(sd); return -1; } return sd; } /* SOCKS5 support * Return a usable socket descriptor after * proxy negotiation, or -1 on any error. */ static int do_proxy_socks5(void) { struct socket_buffer stateful_buf; struct socks5_connect socks5msg; uint32_t inetaddr; char inet6addr[16]; unsigned short proxyport = htons(o.portno); char socksbuf[8]; int sd,len,lenfqdn; struct socks5_request socks5msg2; struct socks5_auth socks5auth; char *proxy_auth; char *username; char *password; sd = do_connect(SOCK_STREAM); if (sd == -1) { loguser("Proxy connection failed: %s.\n", socket_strerror(socket_errno())); return sd; } socket_buffer_init(&stateful_buf, sd); if (o.verbose) { loguser("Connected to proxy %s:%hu\n", inet_socktop(&targetss), inet_port(&targetss)); } zmem(&socks5msg,sizeof(socks5msg)); socks5msg.ver = SOCKS5_VERSION; socks5msg.nmethods = 1; socks5msg.methods[0] = SOCKS5_AUTH_NONE; len = 3; if (o.proxy_auth){ socks5msg.nmethods ++; socks5msg.methods[1] = SOCKS5_AUTH_USERPASS; len ++; } if (send(sd, (char *) &socks5msg, len, 0) < 0) { loguser("Error: proxy request: %s.\n", socket_strerror(socket_errno())); close(sd); return -1; } /* first response just two bytes, version and auth method */ if (socket_buffer_readcount(&stateful_buf, socksbuf, 2) < 0) { loguser("Error: malformed first response from proxy.\n"); close(sd); return -1; } if (socksbuf[0] != 5){ loguser("Error: got wrong server version in response.\n"); close(sd); return -1; } switch(socksbuf[1]) { case SOCKS5_AUTH_NONE: if (o.verbose) loguser("No authentication needed.\n"); break; case SOCKS5_AUTH_GSSAPI: loguser("GSSAPI authentication method not supported.\n"); close(sd); return -1; case SOCKS5_AUTH_USERPASS: if (o.verbose) loguser("Doing username and password authentication.\n"); if(!o.proxy_auth){ loguser("Error: proxy requested to do authentication, but no credentials were provided.\n"); close(sd); return -1; } if (strlen(o.proxy_auth) > SOCKS_BUFF_SIZE-2){ loguser("Error: username and password are too long to fit into buffer.\n"); close(sd); return -1; } /* Split up the proxy auth argument. */ proxy_auth = Strdup(o.proxy_auth); username = strtok(proxy_auth, ":"); password = strtok(NULL, ":"); if (password == NULL || username == NULL) { free(proxy_auth); loguser("Error: empty username or password.\n"); close(sd); return -1; } /* * For username/password authentication the client's authentication request is * field 1: version number, 1 byte (must be 0x01 -- version of subnegotiation) * field 2: username length, 1 byte * field 3: username * field 4: password length, 1 byte * field 5: password * * Server response for username/password authentication: * field 1: version, 1 byte * field 2: status code, 1 byte. * 0x00 = success * any other value = failure, connection must be closed */ socks5auth.ver = 1; socks5auth.data[0] = strlen(username); memcpy(socks5auth.data+1,username,strlen(username)); len = 2 + strlen(username); // (version + strlen) + username socks5auth.data[len-1]=strlen(password); memcpy(socks5auth.data+len,password,strlen(password)); len += 1 + strlen(password); if (send(sd, (char *) &socks5auth, len, 0) < 0) { loguser("Error: sending proxy authentication.\n"); close(sd); return -1; } if (socket_buffer_readcount(&stateful_buf, socksbuf, 2) < 0) { loguser("Error: malformed proxy authentication response.\n"); close(sd); return -1; } if (socksbuf[0] != 1 || socksbuf[1] != 0) { loguser("Error: authentication failed.\n"); close(sd); return -1; } break; default: loguser("Error - can't choose any authentication method.\n"); close(sd); return -1; } zmem(&socks5msg2,sizeof(socks5msg2)); socks5msg2.ver = SOCKS5_VERSION; socks5msg2.cmd = SOCKS_CONNECT; socks5msg2.rsv = 0; switch(getaddrfamily(o.target)) { case 1: // IPv4 address family socks5msg2.atyp = SOCKS5_ATYP_IPv4; inetaddr = inet_addr(o.target); memcpy(socks5msg2.dst, &inetaddr, 4); len = 4; break; case 2: // IPv6 address family socks5msg2.atyp = SOCKS5_ATYP_IPv6; inet_pton(AF_INET6,o.target,&inet6addr); memcpy(socks5msg2.dst, inet6addr,16); len = 16; break; case -1: // FQDN socks5msg2.atyp = SOCKS5_ATYP_NAME; lenfqdn=strlen(o.target); if (lenfqdn > SOCKS_BUFF_SIZE-5){ loguser("Error: host name too long.\n"); close(sd); return -1; } socks5msg2.dst[0]=lenfqdn; memcpy(socks5msg2.dst+1,o.target,lenfqdn); len = 1 + lenfqdn; } memcpy(socks5msg2.dst+len, &proxyport, sizeof(proxyport)); len += 2 + 1 + 3; if (len > sizeof(socks5msg2)){ loguser("Error: address information too large.\n"); close(sd); return -1; } if (send(sd, (char *) &socks5msg2, len, 0) < 0) { loguser("Error: sending proxy request: %s.\n", socket_strerror(socket_errno())); close(sd); return -1; } /* TODO just two bytes for now, need to read more for bind */ if (socket_buffer_readcount(&stateful_buf, socksbuf, 2) < 0) { loguser("Error: malformed second response from proxy.\n"); close(sd); return -1; } switch(socksbuf[1]) { case 0: if (o.verbose) loguser("connection succeeded.\n"); break; case 1: loguser("Error: general SOCKS server failure.\n"); close(sd); return -1; case 2: loguser("Error: connection not allowed by ruleset.\n"); close(sd); return -1; case 3: loguser("Error: Network unreachable.\n"); close(sd); return -1; case 4: loguser("Error: Host unreachable.\n"); close(sd); return -1; case 5: loguser("Error: Connection refused.\n"); close(sd); return -1; case 6: loguser("Error: TTL expired.\n"); close(sd); return -1; case 7: loguser("Error: Command not supported.\n"); close(sd); return -1; case 8: loguser("Error: Address type not supported.\n"); close(sd); return -1; default: loguser("Error: unassigned value in the reply.\n"); close(sd); return -1; } return(sd); } int ncat_connect(void) { nsock_pool mypool; int rc; /* Unless explicitly asked not to do so, ncat uses the * fallback nsock engine to maximize compatibility between * operating systems and the different use cases. */ if (!o.nsock_engine) nsock_set_default_engine("select"); /* Create an nsock pool */ if ((mypool = nsock_pool_new(NULL)) == NULL) bye("Failed to create nsock_pool."); if (o.debug >= 6) nsock_set_loglevel(NSOCK_LOG_DBG_ALL); else if (o.debug >= 3) nsock_set_loglevel(NSOCK_LOG_DBG); else if (o.debug >= 1) nsock_set_loglevel(NSOCK_LOG_INFO); else nsock_set_loglevel(NSOCK_LOG_ERROR); /* Allow connections to broadcast addresses. */ nsock_pool_set_broadcast(mypool, 1); #ifdef HAVE_OPENSSL set_ssl_ctx_options((SSL_CTX *) nsock_pool_ssl_init(mypool, 0)); #endif if (!o.proxytype) { /* A non-proxy connection. Create an iod for a new socket. */ cs.sock_nsi = nsock_iod_new(mypool, NULL); if (cs.sock_nsi == NULL) bye("Failed to create nsock_iod."); if (nsock_iod_set_hostname(cs.sock_nsi, o.target) == -1) bye("Failed to set hostname on iod."); #if HAVE_SYS_UN_H /* For DGRAM UNIX socket we have to use source socket */ if (o.af == AF_UNIX && o.proto == IPPROTO_UDP) { if (srcaddr.storage.ss_family != AF_UNIX) { char *tmp_name = NULL; #if HAVE_MKSTEMP char *tmpdir = getenv("TMPDIR"); size_t size=0, offset=0; strbuf_sprintf(&tmp_name, &size, &offset, "%s/ncat.XXXXXX", tmpdir ? tmpdir : "/tmp"); if (mkstemp(tmp_name) == -1) { bye("Failed to create name for temporary DGRAM source Unix domain socket (mkstemp)."); } unlink(tmp_name); #else /* If no source socket was specified, we have to create temporary one. */ if ((tmp_name = tempnam(NULL, "ncat.")) == NULL) bye("Failed to create name for temporary DGRAM source Unix domain socket (tempnam)."); #endif srcaddr.un.sun_family = AF_UNIX; strncpy(srcaddr.un.sun_path, tmp_name, sizeof(srcaddr.un.sun_path)); free (tmp_name); } nsock_iod_set_localaddr(cs.sock_nsi, &srcaddr.storage, SUN_LEN((struct sockaddr_un *)&srcaddr.storage)); if (o.verbose) loguser("[%s] used as source DGRAM Unix domain socket.\n", srcaddr.un.sun_path); } else #endif switch (srcaddr.storage.ss_family) { case AF_UNSPEC: break; case AF_INET: nsock_iod_set_localaddr(cs.sock_nsi, &srcaddr.storage, sizeof(srcaddr.in)); break; #ifdef AF_INET6 case AF_INET6: nsock_iod_set_localaddr(cs.sock_nsi, &srcaddr.storage, sizeof(srcaddr.in6)); break; #endif #if HAVE_SYS_UN_H case AF_UNIX: nsock_iod_set_localaddr(cs.sock_nsi, &srcaddr.storage, SUN_LEN((struct sockaddr_un *)&srcaddr.storage)); break; #endif default: nsock_iod_set_localaddr(cs.sock_nsi, &srcaddr.storage, sizeof(srcaddr.storage)); break; } if (o.numsrcrtes) { unsigned char *ipopts = NULL; size_t ipoptslen = 0; if (o.af != AF_INET) bye("Sorry, -g can only currently be used with IPv4."); ipopts = buildsrcrte(targetss.in.sin_addr, o.srcrtes, o.numsrcrtes, o.srcrteptr, &ipoptslen); nsock_iod_set_ipoptions(cs.sock_nsi, ipopts, ipoptslen); free(ipopts); /* Nsock has its own copy */ } #if HAVE_SYS_UN_H if (o.af == AF_UNIX) { if (o.proto == IPPROTO_UDP) { nsock_connect_unixsock_datagram(mypool, cs.sock_nsi, connect_handler, NULL, &targetss.sockaddr, SUN_LEN((struct sockaddr_un *)&targetss.sockaddr)); } else { nsock_connect_unixsock_stream(mypool, cs.sock_nsi, connect_handler, o.conntimeout, NULL, &targetss.sockaddr, SUN_LEN((struct sockaddr_un *)&targetss.sockaddr)); } } else #endif if (o.proto == IPPROTO_UDP) { nsock_connect_udp(mypool, cs.sock_nsi, connect_handler, NULL, &targetss.sockaddr, targetsslen, inet_port(&targetss)); } #ifdef HAVE_OPENSSL else if (o.proto == IPPROTO_SCTP && o.ssl) { nsock_connect_ssl(mypool, cs.sock_nsi, connect_handler, o.conntimeout, NULL, &targetss.sockaddr, targetsslen, IPPROTO_SCTP, inet_port(&targetss), NULL); } #endif else if (o.proto == IPPROTO_SCTP) { nsock_connect_sctp(mypool, cs.sock_nsi, connect_handler, o.conntimeout, NULL, &targetss.sockaddr, targetsslen, inet_port(&targetss)); } #ifdef HAVE_OPENSSL else if (o.ssl) { nsock_connect_ssl(mypool, cs.sock_nsi, connect_handler, o.conntimeout, NULL, &targetss.sockaddr, targetsslen, IPPROTO_TCP, inet_port(&targetss), NULL); } #endif else { nsock_connect_tcp(mypool, cs.sock_nsi, connect_handler, o.conntimeout, NULL, &targetss.sockaddr, targetsslen, inet_port(&targetss)); } } else { /* A proxy connection. */ static int connect_socket; if (strcmp(o.proxytype, "http") == 0) { connect_socket = do_proxy_http(); } else if (strcmp(o.proxytype, "socks4") == 0) { connect_socket = do_proxy_socks4(); } else if (strcmp(o.proxytype, "socks5") == 0) { connect_socket = do_proxy_socks5(); } if (connect_socket == -1) return 1; /* Clear out whatever is left in the socket buffer which may be already sent by proxy server along with http response headers. */ //line = socket_buffer_remainder(&stateful_buf, &n); /* Write the leftover data to stdout. */ //Write(STDOUT_FILENO, line, n); /* Once the proxy negotiation is done, Nsock takes control of the socket. */ cs.sock_nsi = nsock_iod_new2(mypool, connect_socket, NULL); /* Create IOD for nsp->stdin */ if ((cs.stdin_nsi = nsock_iod_new2(mypool, 0, NULL)) == NULL) bye("Failed to create stdin nsiod."); post_connect(mypool, cs.sock_nsi); } /* connect */ rc = nsock_loop(mypool, -1); if (o.verbose) { struct timeval end_time; double time; gettimeofday(&end_time, NULL); time = TIMEVAL_MSEC_SUBTRACT(end_time, start_time) / 1000.0; loguser("%lu bytes sent, %lu bytes received in %.2f seconds.\n", nsock_iod_get_write_count(cs.sock_nsi), nsock_iod_get_read_count(cs.sock_nsi), time); } #if HAVE_SYS_UN_H if (o.af == AF_UNIX && o.proto == IPPROTO_UDP) { if (o.verbose) loguser("Deleting source DGRAM Unix domain socket. [%s]\n", srcaddr.un.sun_path); unlink(srcaddr.un.sun_path); } #endif nsock_pool_delete(mypool); return rc == NSOCK_LOOP_ERROR ? 1 : 0; } static void connect_handler(nsock_pool nsp, nsock_event evt, void *data) { enum nse_status status = nse_status(evt); enum nse_type type = nse_type(evt); ncat_assert(type == NSE_TYPE_CONNECT || type == NSE_TYPE_CONNECT_SSL); if (status == NSE_STATUS_ERROR) { loguser("%s.\n", socket_strerror(nse_errorcode(evt))); exit(1); } else if (status == NSE_STATUS_TIMEOUT) { loguser("%s.\n", socket_strerror(ETIMEDOUT)); exit(1); } else { ncat_assert(status == NSE_STATUS_SUCCESS); } #ifdef HAVE_OPENSSL if (nsock_iod_check_ssl(cs.sock_nsi)) { /* Check the domain name. ssl_post_connect_check prints an error message if appropriate. */ if (!ssl_post_connect_check((SSL *)nsock_iod_get_ssl(cs.sock_nsi), o.target)) bye("Certificate verification error."); } #endif connect_report(cs.sock_nsi); /* Create IOD for nsp->stdin */ if ((cs.stdin_nsi = nsock_iod_new2(nsp, 0, NULL)) == NULL) bye("Failed to create stdin nsiod."); post_connect(nsp, nse_iod(evt)); } /* Handle --exec if appropriate, otherwise start the initial read events and set the idle timeout. */ static void post_connect(nsock_pool nsp, nsock_iod iod) { /* Command to execute. */ if (o.cmdexec) { struct fdinfo info; info.fd = nsock_iod_get_sd(iod); #ifdef HAVE_OPENSSL info.ssl = (SSL *)nsock_iod_get_ssl(iod); #endif /* Convert Nsock's non-blocking socket to an ordinary blocking one. It's possible for a program to write fast enough that it will get an EAGAIN on write on a non-blocking socket. */ block_socket(info.fd); netexec(&info, o.cmdexec); } /* Start the initial reads. */ if (!o.sendonly) nsock_read(nsp, cs.sock_nsi, read_socket_handler, -1, NULL); if (!o.recvonly) nsock_readbytes(nsp, cs.stdin_nsi, read_stdin_handler, -1, NULL, 0); /* The --idle-timeout option says to exit after a certain period of inactivity. We start a timer here and reset it on every read event; see refresh_idle_timer. */ if (o.idletimeout > 0) { cs.idle_timer_event_id = nsock_timer_create(nsp, idle_timer_handler, o.idletimeout, NULL); } } static void read_stdin_handler(nsock_pool nsp, nsock_event evt, void *data) { enum nse_status status = nse_status(evt); enum nse_type type = nse_type(evt); char *buf, *tmp = NULL; int nbytes; ncat_assert(type == NSE_TYPE_READ); if (status == NSE_STATUS_EOF) { shutdown(nsock_iod_get_sd(cs.sock_nsi), SHUT_WR); /* In --send-only mode or non-TCP mode, exit after EOF on stdin. */ if (o.proto != IPPROTO_TCP || (o.proto == IPPROTO_TCP && o.sendonly)) nsock_loop_quit(nsp); return; } else if (status == NSE_STATUS_ERROR) { loguser("%s.\n", socket_strerror(nse_errorcode(evt))); exit(1); } else if (status == NSE_STATUS_TIMEOUT) { loguser("%s.\n", socket_strerror(ETIMEDOUT)); exit(1); } else if (status == NSE_STATUS_CANCELLED || status == NSE_STATUS_KILL) { return; } else { ncat_assert(status == NSE_STATUS_SUCCESS); } buf = nse_readbuf(evt, &nbytes); /* read from stdin */ if (o.linedelay) ncat_delay_timer(o.linedelay); if (o.crlf) { if (fix_line_endings(buf, &nbytes, &tmp, &cs.crlf_state)) buf = tmp; } nsock_write(nsp, cs.sock_nsi, write_socket_handler, -1, NULL, buf, nbytes); ncat_log_send(buf, nbytes); if (tmp) free(tmp); refresh_idle_timer(nsp); } static void read_socket_handler(nsock_pool nsp, nsock_event evt, void *data) { enum nse_status status = nse_status(evt); enum nse_type type = nse_type(evt); char *buf; int nbytes; ncat_assert(type == NSE_TYPE_READ); if (status == NSE_STATUS_EOF) { Close(STDOUT_FILENO); /* In --recv-only mode or non-TCP mode, exit after EOF on the socket. */ if (o.proto != IPPROTO_TCP || (o.proto == IPPROTO_TCP && o.recvonly)) nsock_loop_quit(nsp); return; } else if (status == NSE_STATUS_ERROR) { loguser("%s.\n", socket_strerror(nse_errorcode(evt))); exit(1); } else if (status == NSE_STATUS_TIMEOUT) { loguser("%s.\n", socket_strerror(ETIMEDOUT)); exit(1); } else if (status == NSE_STATUS_CANCELLED || status == NSE_STATUS_KILL) { return; } else { ncat_assert(status == NSE_STATUS_SUCCESS); } buf = nse_readbuf(evt, &nbytes); if (o.linedelay) ncat_delay_timer(o.linedelay); if (o.telnet) dotelnet(nsock_iod_get_sd(nse_iod(evt)), (unsigned char *) buf, nbytes); /* Write socket data to stdout */ Write(STDOUT_FILENO, buf, nbytes); ncat_log_recv(buf, nbytes); nsock_readbytes(nsp, cs.sock_nsi, read_socket_handler, -1, NULL, 0); refresh_idle_timer(nsp); } static void write_socket_handler(nsock_pool nsp, nsock_event evt, void *data) { enum nse_status status = nse_status(evt); enum nse_type type = nse_type(evt); ncat_assert(type == NSE_TYPE_WRITE); if (status == NSE_STATUS_ERROR) { loguser("%s.\n", socket_strerror(nse_errorcode(evt))); exit(1); } else if (status == NSE_STATUS_TIMEOUT) { loguser("%s.\n", socket_strerror(ETIMEDOUT)); exit(1); } else if (status == NSE_STATUS_CANCELLED || status == NSE_STATUS_KILL) { return; } else { ncat_assert(status == NSE_STATUS_SUCCESS); } /* The write to the socket was successful. Allow reading more from stdin now. */ nsock_readbytes(nsp, cs.stdin_nsi, read_stdin_handler, -1, NULL, 0); } static void idle_timer_handler(nsock_pool nsp, nsock_event evt, void *data) { enum nse_status status = nse_status(evt); enum nse_type type = nse_type(evt); ncat_assert(type == NSE_TYPE_TIMER); if (status == NSE_STATUS_CANCELLED || status == NSE_STATUS_KILL) return; ncat_assert(status == NSE_STATUS_SUCCESS); loguser("Idle timeout expired (%d ms).\n", o.idletimeout); exit(1); } static void refresh_idle_timer(nsock_pool nsp) { if (o.idletimeout <= 0) return; nsock_event_cancel(nsp, cs.idle_timer_event_id, 0); cs.idle_timer_event_id = nsock_timer_create(nsp, idle_timer_handler, o.idletimeout, NULL); }