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-rw-r--r--svr-main.c420
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diff --git a/svr-main.c b/svr-main.c
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+/*
+ * Dropbear - a SSH2 server
+ *
+ * Copyright (c) 2002-2006 Matt Johnston
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "dbutil.h"
+#include "session.h"
+#include "buffer.h"
+#include "signkey.h"
+#include "runopts.h"
+#include "random.h"
+
+static size_t listensockets(int *sock, size_t sockcount, int *maxfd);
+static void sigchld_handler(int dummy);
+static void sigsegv_handler(int);
+static void sigintterm_handler(int fish);
+#ifdef INETD_MODE
+static void main_inetd();
+#endif
+#ifdef NON_INETD_MODE
+static void main_noinetd();
+#endif
+static void commonsetup();
+
+#if defined(DBMULTI_dropbear) || !defined(DROPBEAR_MULTI)
+#if defined(DBMULTI_dropbear) && defined(DROPBEAR_MULTI)
+int dropbear_main(int argc, char ** argv)
+#else
+int main(int argc, char ** argv)
+#endif
+{
+ _dropbear_exit = svr_dropbear_exit;
+ _dropbear_log = svr_dropbear_log;
+
+ /* get commandline options */
+ svr_getopts(argc, argv);
+
+#ifdef INETD_MODE
+ /* service program mode */
+ if (svr_opts.inetdmode) {
+ main_inetd();
+ /* notreached */
+ }
+#endif
+
+#ifdef NON_INETD_MODE
+ main_noinetd();
+ /* notreached */
+#endif
+
+ dropbear_exit("Compiled without normal mode, can't run without -i\n");
+ return -1;
+}
+#endif
+
+#ifdef INETD_MODE
+static void main_inetd() {
+
+ struct sockaddr_storage remoteaddr;
+ socklen_t remoteaddrlen;
+ char * addrstring = NULL;
+
+ /* Set up handlers, syslog, seed random */
+ commonsetup();
+
+ remoteaddrlen = sizeof(remoteaddr);
+ if (getpeername(0, (struct sockaddr*)&remoteaddr, &remoteaddrlen) < 0) {
+ dropbear_exit("Unable to getpeername: %s", strerror(errno));
+ }
+
+ /* In case our inetd was lax in logging source addresses */
+ addrstring = getaddrstring(&remoteaddr, 1);
+ dropbear_log(LOG_INFO, "Child connection from %s", addrstring);
+
+ /* Don't check the return value - it may just fail since inetd has
+ * already done setsid() after forking (xinetd on Darwin appears to do
+ * this */
+ setsid();
+
+ /* Start service program
+ * -1 is a dummy childpipe, just something we can close() without
+ * mattering. */
+ svr_session(0, -1, getaddrhostname(&remoteaddr), addrstring);
+
+ /* notreached */
+}
+#endif /* INETD_MODE */
+
+#ifdef NON_INETD_MODE
+void main_noinetd() {
+ fd_set fds;
+ struct timeval seltimeout;
+ unsigned int i, j;
+ int val;
+ int maxsock = -1;
+ int listensocks[MAX_LISTEN_ADDR];
+ size_t listensockcount = 0;
+ FILE *pidfile = NULL;
+
+ int childpipes[MAX_UNAUTH_CLIENTS];
+ char * preauth_addrs[MAX_UNAUTH_CLIENTS];
+
+ int childsock;
+ int childpipe[2];
+
+ // Note: commonsetup() must happen before we daemon()ise. Otherwise
+ // daemon() will chdir("/"), and we won't be able to find local-dir hostkeys.
+ commonsetup();
+
+ /* fork */
+ if (svr_opts.forkbg) {
+ int closefds = 0;
+#ifndef DEBUG_TRACE
+ if (!svr_opts.usingsyslog) {
+ closefds = 1;
+ }
+#endif
+ if (daemon(0, closefds) < 0) {
+ dropbear_exit("Failed to daemonize: %s", strerror(errno));
+ }
+ }
+
+ /* should be done after syslog is working */
+ if (svr_opts.forkbg) {
+ dropbear_log(LOG_INFO, "Running in background");
+ } else {
+ dropbear_log(LOG_INFO, "Not forking");
+ }
+
+ /* create a PID file so that we can be killed easily */
+ pidfile = fopen(svr_opts.pidfile, "w");
+ if (pidfile) {
+ fprintf(pidfile, "%d\n", getpid());
+ fclose(pidfile);
+ }
+
+ /* sockets to identify pre-authenticated clients */
+ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) {
+ childpipes[i] = -1;
+ }
+ bzero(preauth_addrs, sizeof(preauth_addrs));
+
+ /* Set up the listening sockets */
+ listensockcount = listensockets(listensocks, MAX_LISTEN_ADDR, &maxsock);
+ if (listensockcount == 0)
+ {
+ dropbear_exit("No listening ports available.");
+ }
+
+ /* incoming connection select loop */
+ for(;;) {
+
+ FD_ZERO(&fds);
+
+ seltimeout.tv_sec = 60;
+ seltimeout.tv_usec = 0;
+
+ /* listening sockets */
+ for (i = 0; i < listensockcount; i++) {
+ FD_SET(listensocks[i], &fds);
+ }
+
+ /* pre-authentication clients */
+ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) {
+ if (childpipes[i] >= 0) {
+ FD_SET(childpipes[i], &fds);
+ maxsock = MAX(maxsock, childpipes[i]);
+ }
+ }
+
+ val = select(maxsock+1, &fds, NULL, NULL, &seltimeout);
+
+ if (exitflag) {
+ unlink(svr_opts.pidfile);
+ dropbear_exit("Terminated by signal");
+ }
+
+ if (val == 0) {
+ /* timeout reached */
+ continue;
+ }
+
+ if (val < 0) {
+ if (errno == EINTR) {
+ continue;
+ }
+ dropbear_exit("Listening socket error");
+ }
+
+ /* close fds which have been authed or closed - svr-auth.c handles
+ * closing the auth sockets on success */
+ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) {
+ if (childpipes[i] >= 0 && FD_ISSET(childpipes[i], &fds)) {
+ m_close(childpipes[i]);
+ childpipes[i] = -1;
+ m_free(preauth_addrs[i]);
+ }
+ }
+
+ /* handle each socket which has something to say */
+ for (i = 0; i < listensockcount; i++) {
+
+ struct sockaddr_storage remoteaddr;
+ socklen_t remoteaddrlen = 0;
+ size_t num_unauthed_for_addr = 0;
+ size_t num_unauthed_total = 0;
+ char * remote_addr_str = NULL;
+ pid_t fork_ret = 0;
+ size_t conn_idx = 0;
+
+ if (!FD_ISSET(listensocks[i], &fds))
+ continue;
+
+ remoteaddrlen = sizeof(remoteaddr);
+ childsock = accept(listensocks[i],
+ (struct sockaddr*)&remoteaddr, &remoteaddrlen);
+
+ if (childsock < 0) {
+ /* accept failed */
+ continue;
+ }
+
+ /* Limit the number of unauthenticated connections per IP */
+ remote_addr_str = getaddrstring(&remoteaddr, 0);
+
+ num_unauthed_for_addr = 0;
+ num_unauthed_total = 0;
+ for (j = 0; j < MAX_UNAUTH_CLIENTS; j++) {
+ if (childpipes[j] >= 0) {
+ num_unauthed_total++;
+ if (strcmp(remote_addr_str, preauth_addrs[j]) == 0) {
+ num_unauthed_for_addr++;
+ }
+ } else {
+ /* a free slot */
+ conn_idx = j;
+ }
+ }
+
+ if (num_unauthed_total >= MAX_UNAUTH_CLIENTS
+ || num_unauthed_for_addr >= MAX_UNAUTH_PER_IP) {
+ goto out;
+ }
+
+ if (pipe(childpipe) < 0) {
+ TRACE(("error creating child pipe"))
+ goto out;
+ }
+
+ fork_ret = fork();
+ if (fork_ret < 0) {
+ dropbear_log(LOG_WARNING, "error forking: %s", strerror(errno));
+ goto out;
+
+ } else if (fork_ret > 0) {
+
+ /* parent */
+ childpipes[conn_idx] = childpipe[0];
+ m_close(childpipe[1]);
+ preauth_addrs[conn_idx] = remote_addr_str;
+ remote_addr_str = NULL;
+
+ } else {
+
+ /* child */
+ char * addrstring = NULL;
+#ifdef DEBUG_FORKGPROF
+ extern void _start(void), etext(void);
+ monstartup((u_long)&_start, (u_long)&etext);
+#endif /* DEBUG_FORKGPROF */
+
+ m_free(remote_addr_str);
+ addrstring = getaddrstring(&remoteaddr, 1);
+ dropbear_log(LOG_INFO, "Child connection from %s", addrstring);
+
+ if (setsid() < 0) {
+ dropbear_exit("setsid: %s", strerror(errno));
+ }
+
+ /* make sure we close sockets */
+ for (i = 0; i < listensockcount; i++) {
+ m_close(listensocks[i]);
+ }
+
+ m_close(childpipe[0]);
+
+ /* start the session */
+ svr_session(childsock, childpipe[1],
+ getaddrhostname(&remoteaddr),
+ addrstring);
+ /* don't return */
+ dropbear_assert(0);
+ }
+
+out:
+ /* This section is important for the parent too */
+ m_close(childsock);
+ if (remote_addr_str) {
+ m_free(remote_addr_str);
+ }
+ }
+ } /* for(;;) loop */
+
+ /* don't reach here */
+}
+#endif /* NON_INETD_MODE */
+
+
+/* catch + reap zombie children */
+static void sigchld_handler(int UNUSED(unused)) {
+ struct sigaction sa_chld;
+
+ while(waitpid(-1, NULL, WNOHANG) > 0);
+
+ sa_chld.sa_handler = sigchld_handler;
+ sa_chld.sa_flags = SA_NOCLDSTOP;
+ if (sigaction(SIGCHLD, &sa_chld, NULL) < 0) {
+ dropbear_exit("signal() error");
+ }
+}
+
+/* catch any segvs */
+static void sigsegv_handler(int UNUSED(unused)) {
+ fprintf(stderr, "Aiee, segfault! You should probably report "
+ "this as a bug to the developer\n");
+ exit(EXIT_FAILURE);
+}
+
+/* catch ctrl-c or sigterm */
+static void sigintterm_handler(int UNUSED(unused)) {
+
+ exitflag = 1;
+}
+
+/* Things used by inetd and non-inetd modes */
+static void commonsetup() {
+
+ struct sigaction sa_chld;
+#ifndef DISABLE_SYSLOG
+ if (svr_opts.usingsyslog) {
+ startsyslog();
+ }
+#endif
+
+ /* set up cleanup handler */
+ if (signal(SIGINT, sigintterm_handler) == SIG_ERR ||
+#ifndef DEBUG_VALGRIND
+ signal(SIGTERM, sigintterm_handler) == SIG_ERR ||
+#endif
+ signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
+ dropbear_exit("signal() error");
+ }
+
+ /* catch and reap zombie children */
+ sa_chld.sa_handler = sigchld_handler;
+ sa_chld.sa_flags = SA_NOCLDSTOP;
+ if (sigaction(SIGCHLD, &sa_chld, NULL) < 0) {
+ dropbear_exit("signal() error");
+ }
+ if (signal(SIGSEGV, sigsegv_handler) == SIG_ERR) {
+ dropbear_exit("signal() error");
+ }
+
+ /* Now we can setup the hostkeys - needs to be after logging is on,
+ * otherwise we might end up blatting error messages to the socket */
+ loadhostkeys();
+
+ seedrandom();
+}
+
+/* Set up listening sockets for all the requested ports */
+static size_t listensockets(int *sock, size_t sockcount, int *maxfd) {
+
+ unsigned int i;
+ char* errstring = NULL;
+ size_t sockpos = 0;
+ int nsock;
+
+ TRACE(("listensockets: %d to try\n", svr_opts.portcount))
+
+ for (i = 0; i < svr_opts.portcount; i++) {
+
+ TRACE(("listening on '%s'", svr_opts.ports[i]))
+
+ nsock = dropbear_listen("", svr_opts.ports[i], &sock[sockpos],
+ sockcount - sockpos,
+ &errstring, maxfd);
+
+ if (nsock < 0) {
+ dropbear_log(LOG_WARNING, "Failed listening on '%s': %s",
+ svr_opts.ports[i], errstring);
+ m_free(errstring);
+ continue;
+ }
+
+ sockpos += nsock;
+
+ }
+ return sockpos;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-04 04:27:21 +0000