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+
+/***************************************************************************
+ * nmap_ftp.cc -- Nmap's FTP routines used for FTP bounce scan (-b)
+ * *
+ ***********************IMPORTANT NMAP LICENSE TERMS************************
+ *
+ * The Nmap Security Scanner is (C) 1996-2023 Nmap Software LLC ("The Nmap
+ * Project"). Nmap is also a registered trademark of the Nmap Project.
+ *
+ * This program is distributed under the terms of the Nmap Public Source
+ * License (NPSL). The exact license text applying to a particular Nmap
+ * release or source code control revision is contained in the LICENSE
+ * file distributed with that version of Nmap or source code control
+ * revision. More Nmap copyright/legal information is available from
+ * https://nmap.org/book/man-legal.html, and further information on the
+ * NPSL license itself can be found at https://nmap.org/npsl/ . This
+ * header summarizes some key points from the Nmap license, but is no
+ * substitute for the actual license text.
+ *
+ * Nmap is generally free for end users to download and use themselves,
+ * including commercial use. It is available from https://nmap.org.
+ *
+ * The Nmap license generally prohibits companies from using and
+ * redistributing Nmap in commercial products, but we sell a special Nmap
+ * OEM Edition with a more permissive license and special features for
+ * this purpose. See https://nmap.org/oem/
+ *
+ * If you have received a written Nmap license agreement or contract
+ * stating terms other than these (such as an Nmap OEM license), you may
+ * choose to use and redistribute Nmap under those terms instead.
+ *
+ * The official Nmap Windows builds include the Npcap software
+ * (https://npcap.com) for packet capture and transmission. It is under
+ * separate license terms which forbid redistribution without special
+ * permission. So the official Nmap Windows builds may not be redistributed
+ * without special permission (such as an Nmap OEM license).
+ *
+ * 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 submit your changes as a Github PR
+ * or by email to the dev@nmap.org mailing list for possible incorporation into
+ * the main distribution. Unless you specify otherwise, it is understood that
+ * you are offering us very broad rights to use your submissions as described in
+ * the Nmap Public Source License Contributor Agreement. This is important
+ * because we fund the project by selling licenses with various terms, and also
+ * because the inability to relicense code has caused devastating problems for
+ * other Free Software projects (such as KDE and NASM).
+ *
+ * The free version of Nmap 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. Warranties,
+ * indemnification and commercial support are all available through the
+ * Npcap OEM program--see https://nmap.org/oem/
+ *
+ ***************************************************************************/
+
+/* $Id$ */
+#include "nmap.h"
+#include "nmap_ftp.h"
+#include "output.h"
+#include "NmapOps.h"
+#include "nmap_error.h"
+#include "tcpip.h"
+#include "Target.h"
+#include "nmap_tty.h"
+extern NmapOps o;
+
+struct ftpinfo get_default_ftpinfo(void) {
+#if (defined(IN_ADDR_DEEPSTRUCT) || defined(SOLARIS))
+ /* Note that struct in_addr in solaris is 3 levels deep just to store an
+ * unsigned int! */
+ struct ftpinfo ftp = { FTPUSER, FTPPASS, "", { { { 0 } } } , 21, 0};
+#else
+ struct ftpinfo ftp = { FTPUSER, FTPPASS, "", { 0 }, 21, 0};
+#endif
+ return ftp;
+}
+
+/* parse a URL stype ftp string of the form user:pass@server:portno */
+int parse_bounce_argument(struct ftpinfo *ftp, char *url) {
+ char *p = url, *q, *s;
+
+ if ((q = strrchr(url, '@'))) { /* we have user and/or pass */
+ *q++ = '\0';
+
+ if ((s = strchr(p, ':'))) { /* we have user AND pass */
+ *s++ = '\0';
+ strncpy(ftp->pass, s, 255);
+ } else { /* we ONLY have user */
+ log_write(LOG_STDOUT, "Assuming %s is a username, and using the default password: %s\n",
+ p, ftp->pass);
+ }
+
+ strncpy(ftp->user, p, 63);
+ } else {
+ q = url;
+ }
+
+ /* q points to beginning of server name */
+ if ((s = strchr(q, ':'))) { /* we have portno */
+ *s++ = '\0';
+ ftp->port = atoi(s);
+ }
+
+ strncpy(ftp->server_name, q, FQDN_LEN+1);
+
+ ftp->user[63] = ftp->pass[255] = ftp->server_name[FQDN_LEN] = 0;
+
+ return 1;
+}
+
+int ftp_anon_connect(struct ftpinfo *ftp) {
+ int sd;
+ struct sockaddr_in sock;
+ int res;
+ char recvbuf[2048];
+ char command[512];
+
+ if (o.verbose || o.debugging)
+ log_write(LOG_STDOUT, "Attempting connection to ftp://%s:%s@%s:%i\n",
+ ftp->user, ftp->pass, ftp->server_name, ftp->port);
+
+ if ((sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
+ gh_perror("Couldn't create %s socket", __func__);
+ return 0;
+ }
+ socket_bindtodevice(sd, o.device);
+
+ sock.sin_family = AF_INET;
+ sock.sin_addr.s_addr = ftp->server.s_addr;
+ sock.sin_port = htons(ftp->port);
+ res = connect(sd, (struct sockaddr *) &sock, sizeof(struct sockaddr_in));
+ if (res < 0)
+ fatal("Your FTP bounce proxy server won't talk to us!");
+ if (o.verbose || o.debugging)
+ log_write(LOG_STDOUT, "Connected:");
+ while ((res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 7, NULL)) > 0) {
+ if (o.debugging || o.verbose) {
+ recvbuf[res] = '\0';
+ log_write(LOG_STDOUT, "%s", recvbuf);
+ }
+ }
+ if (res < 0)
+ pfatal("recv problem from FTP bounce server");
+
+ Snprintf(command, 511, "USER %s\r\n", ftp->user);
+
+ send(sd, command, strlen(command), 0);
+ res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 12, NULL);
+ if (res <= 0)
+ pfatal("recv problem from FTP bounce server");
+ recvbuf[res] = '\0';
+ if (o.debugging)
+ log_write(LOG_STDOUT, "sent username, received: %s", recvbuf);
+ if (recvbuf[0] == '5')
+ fatal("Your FTP bounce server doesn't like the username \"%s\"", ftp->user);
+
+ if (!strncmp(recvbuf, "230", 3)) {
+ // 230 User logged in
+ // No need to send PASS
+ if (o.verbose)
+ log_write(LOG_STDOUT, "Login credentials accepted by FTP server!\n");
+ ftp->sd = sd;
+ return sd;
+ }
+ Snprintf(command, 511, "PASS %s\r\n", ftp->pass);
+
+ send(sd, command, strlen(command), 0);
+ res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 12, NULL);
+ if (res < 0)
+ pfatal("recv problem from FTP bounce server");
+ if (!res) {
+ error("Timeout from bounce server ...");
+ } else {
+ recvbuf[res] = '\0';
+ if (o.debugging)
+ log_write(LOG_STDOUT, "sent password, received: %s", recvbuf);
+ if (recvbuf[0] == '5')
+ fatal("Your FTP bounce server refused login combo (%s/%s)", ftp->user, ftp->pass);
+ }
+ while ((res = recvtime(sd, recvbuf, sizeof(recvbuf) - 1, 2, NULL)) > 0) {
+ if (o.debugging) {
+ recvbuf[res] = '\0';
+ log_write(LOG_STDOUT, "%s", recvbuf);
+ }
+ }
+ if (res < 0)
+ pfatal("recv problem from FTP bounce server");
+ if (o.verbose)
+ log_write(LOG_STDOUT, "Login credentials accepted by FTP server!\n");
+
+ ftp->sd = sd;
+ return sd;
+}
+
+/* FTP bounce attack scan. This function is rather lame and should be
+ rewritten. But I don't think it is used much anyway. If I'm going to
+ allow FTP bounce scan, I should really allow SOCKS proxy scan. */
+void bounce_scan(Target *target, u16 *portarray, int numports,
+ struct ftpinfo *ftp) {
+ o.current_scantype = BOUNCE_SCAN;
+
+ ScanProgressMeter *SPM;
+ int res , sd = ftp->sd, i = 0;
+ const char *t = (const char *)target->v4hostip();
+ int retriesleft = FTP_RETRIES;
+ char recvbuf[2048];
+ char targetstr[20];
+ char command[512];
+ unsigned short portno, p1, p2;
+ int timedout;
+ bool privok = false;
+
+ if (numports == 0)
+ return; /* nothing to scan for */
+
+ Snprintf(targetstr, 20, "%d,%d,%d,%d,", UC(t[0]), UC(t[1]), UC(t[2]), UC(t[3]));
+
+ SPM = new ScanProgressMeter(scantype2str(BOUNCE_SCAN));
+ for (i = 0; i < numports; i++) {
+
+ /* Check for timeout */
+ if (target->timedOut(NULL)) {
+ Snprintf(recvbuf, sizeof(recvbuf), "Target timed out");
+ SPM->endTask(NULL, recvbuf);
+ delete SPM;
+ return;
+ }
+
+ portno = htons(portarray[i]);
+ p1 = ((unsigned char *) &portno)[0];
+ p2 = ((unsigned char *) &portno)[1];
+ Snprintf(command, 512, "PORT %s%i,%i\r\n", targetstr, p1, p2);
+ if (o.debugging)
+ log_write(LOG_STDOUT, "Attempting command: %s", command);
+ if (send(sd, command, strlen(command), 0) < 0 ) {
+ gh_perror("send in %s", __func__);
+ if (retriesleft) {
+ if (o.verbose || o.debugging)
+ log_write(LOG_STDOUT, "Our FTP proxy server hung up on us! retrying\n");
+ retriesleft--;
+ close(sd);
+ ftp->sd = ftp_anon_connect(ftp);
+ if (ftp->sd < 0) {
+ Snprintf(recvbuf, sizeof(recvbuf), "Error connecting");
+ SPM->endTask(NULL, recvbuf);
+ delete SPM;
+ return;
+ }
+ sd = ftp->sd;
+ i--;
+ } else {
+ error("Our socket descriptor is dead and we are out of retries. Giving up.");
+ close(sd);
+ ftp->sd = -1;
+ Snprintf(recvbuf, sizeof(recvbuf), "Max retries exceeded");
+ SPM->endTask(NULL, recvbuf);
+ delete SPM;
+ return;
+ }
+ } else { /* Our send is good */
+ res = recvtime(sd, recvbuf, 2048, 15, NULL);
+ if (res <= 0) {
+ perror("recv problem from FTP bounce server");
+ } else { /* our recv is good */
+ recvbuf[res] = '\0';
+ if (o.debugging)
+ log_write(LOG_STDOUT, "result of port query on port %i: %s",
+ portarray[i], recvbuf);
+ if (recvbuf[0] == '5' && !privok) {
+ if (portarray[i] > 1023) {
+ fatal("Your FTP bounce server sucks, it won't let us feed bogus ports!");
+ } else {
+ error("Your FTP bounce server doesn't allow privileged ports, skipping them.");
+ while (i < numports && portarray[i] < 1024) i++;
+ if (i >= numports) {
+ fatal("And you didn't want to scan any unprivileged ports. Giving up.");
+ }
+ }
+ } else { /* Not an error message */
+ if (portarray[i] < 1024) {
+ privok = true;
+ }
+ if (send(sd, "LIST\r\n", 6, 0) > 0 ) {
+ res = recvtime(sd, recvbuf, 2048, 12, &timedout);
+ if (res < 0) {
+ perror("recv problem from FTP bounce server");
+ } else if (res == 0) {
+ recvbuf[res] = '\0';
+ if (timedout)
+ target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_FILTERED);
+ else target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_CLOSED);
+ } else {
+ recvbuf[res] = '\0';
+ if (o.debugging)
+ log_write(LOG_STDOUT, "result of LIST: %s", recvbuf);
+ if (!strncmp(recvbuf, "500", 3)) {
+ /* oh dear, we are not aligned properly */
+ if (o.verbose || o.debugging)
+ error("FTP command misalignment detected ... correcting.");
+ res = recvtime(sd, recvbuf, 2048, 10, NULL);
+ }
+ if (recvbuf[0] == '1') {
+ res = recvtime(sd, recvbuf, 2048, 10, &timedout);
+ if (res < 0)
+ perror("recv problem from FTP bounce server");
+ else if (timedout || res == 0) {
+ // Timed out waiting for LIST to complete; probably filtered.
+ if(send(sd, "ABOR\r\n", 6, 0) > 0) {
+ target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_FILTERED);
+ }
+ // Get response and discard
+ res = recvtime(sd, recvbuf, 2048, 10, &timedout);
+ recvbuf[0] = '\0';
+ goto nextport;
+ }
+ else {
+ recvbuf[res] = '\0';
+ if (o.debugging)
+ log_write(LOG_STDOUT, "nxt line: %s", recvbuf);
+ if (recvbuf[0] == '4' && recvbuf[1] == '2' && recvbuf[2] == '6') {
+ target->ports.forgetPort(portarray[i], IPPROTO_TCP);
+ if (o.debugging || o.verbose)
+ log_write(LOG_STDOUT, "Changed my mind about port %i\n", portarray[i]);
+ }
+ }
+ }
+ if (recvbuf[0] == '2') {
+ target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_OPEN);
+ } else {
+ /* This means the port is closed ... */
+ target->ports.setPortState(portarray[i], IPPROTO_TCP, PORT_CLOSED);
+ }
+ }
+ }
+ }
+ }
+ }
+ nextport:
+ if (SPM->mayBePrinted(NULL)) {
+ SPM->printStatsIfNecessary((double) i / numports, NULL);
+ }
+ else if (keyWasPressed()) {
+ SPM->printStats((double) i / numports, NULL);
+ log_flush(LOG_STDOUT);
+ }
+ }
+
+ Snprintf(recvbuf, sizeof(recvbuf), "%d total ports", numports);
+ SPM->endTask(NULL, recvbuf);
+ delete SPM;
+ return;
+}
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