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-rw-r--r--svr-main.c347
1 files changed, 347 insertions, 0 deletions
diff --git a/svr-main.c b/svr-main.c
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+/*
+ * Dropbear - a SSH2 server
+ *
+ * Copyright (c) 2002,2003 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"
+
+static int listensockets(int *sock, int *maxfd);
+static void sigchld_handler(int dummy);
+static void sigsegv_handler(int);
+static void sigintterm_handler(int fish);
+
+static int childpipes[MAX_UNAUTH_CLIENTS];
+
+#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
+{
+
+ fd_set fds;
+ struct timeval seltimeout;
+ unsigned int i, j;
+ int val;
+ int maxsock = -1;
+ struct sockaddr remoteaddr;
+ int remoteaddrlen;
+ int listensocks[MAX_LISTEN_ADDR];
+ unsigned int listensockcount = 0;
+ FILE * pidfile;
+
+ int childsock;
+ pid_t childpid;
+ int childpipe[2];
+
+ struct sigaction sa_chld;
+
+ _dropbear_exit = svr_dropbear_exit;
+ _dropbear_log = svr_dropbear_log;
+
+ /* get commandline options */
+ svr_getopts(argc, argv);
+
+ /* 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 create background process: %s",
+ strerror(errno));
+ }
+ }
+
+#ifndef DISABLE_SYSLOG
+ if (svr_opts.usingsyslog) {
+ startsyslog();
+ }
+#endif
+
+ /* 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(DROPBEAR_PIDFILE, "w");
+ if (pidfile) {
+ fprintf(pidfile, "%d\n", getpid());
+ fclose(pidfile);
+ }
+
+ /* 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");
+ }
+
+ /* sockets to identify pre-authenticated clients */
+ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) {
+ childpipes[i] = -1;
+ }
+
+ /* Set up the listening sockets */
+ /* XXX XXX ports */
+ listensockcount = listensockets(listensocks, &maxsock);
+
+ /* 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(DROPBEAR_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 - 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)) {
+ close(childpipes[i]);
+ childpipes[i] = -1;
+ }
+ }
+
+ /* handle each socket which has something to say */
+ for (i = 0; i < listensockcount; i++) {
+ if (!FD_ISSET(listensocks[i], &fds))
+ continue;
+
+ /* child connection XXX - ip6 stuff here */
+ remoteaddrlen = sizeof(struct sockaddr_in);
+ childsock = accept(listensocks[i], &remoteaddr, &remoteaddrlen);
+
+ if (childsock < 0) {
+ /* accept failed */
+ continue;
+ }
+
+ /* check for max number of connections not authorised */
+ for (j = 0; j < MAX_UNAUTH_CLIENTS; j++) {
+ if (childpipes[j] < 0) {
+ break;
+ }
+ }
+
+ if (j == MAX_UNAUTH_CLIENTS) {
+ /* no free connections */
+ /* TODO - possibly log, though this would be an easy way
+ * to fill logs/disk */
+ close(childsock);
+ continue;
+ }
+
+ if (pipe(childpipe) < 0) {
+ TRACE(("error creating child pipe"));
+ close(childsock);
+ continue;
+ }
+
+ if ((childpid = fork()) == 0) {
+
+ /* child */
+ char * addrstring = NULL;
+#ifdef DEBUG_FORKGPROF
+ extern void _start(void), etext(void);
+ monstartup((u_long)&_start, (u_long)&etext);
+#endif /* DEBUG_FORKGPROF */
+
+ addrstring = getaddrstring(&remoteaddr);
+ dropbear_log(LOG_INFO, "Child connection from %s", addrstring);
+ m_free(addrstring);
+
+ if (setsid() < 0) {
+ dropbear_exit("setsid: %s", strerror(errno));
+ }
+
+ /* make sure we close sockets */
+ for (i = 0; i < listensockcount; i++) {
+ if (m_close(listensocks[i]) == DROPBEAR_FAILURE) {
+ dropbear_exit("Couldn't close socket");
+ }
+ }
+
+ if (m_close(childpipe[0]) == DROPBEAR_FAILURE) {
+ dropbear_exit("Couldn't close socket");
+ }
+
+ /* start the session */
+ svr_session(childsock, childpipe[1],
+ getaddrhostname(&remoteaddr));
+ /* don't return */
+ assert(0);
+ }
+
+ /* parent */
+ childpipes[j] = childpipe[0];
+ if (m_close(childpipe[1]) == DROPBEAR_FAILURE
+ || m_close(childsock) == DROPBEAR_FAILURE) {
+ dropbear_exit("Couldn't close socket");
+ }
+ }
+ } /* for(;;) loop */
+
+ /* don't reach here */
+ return -1;
+}
+#endif
+
+/* catch + reap zombie children */
+static void sigchld_handler(int fish) {
+ 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 fish) {
+ 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 fish) {
+
+ exitflag = 1;
+}
+
+/* Set up listening sockets for all the requested ports */
+static int listensockets(int *sock, int *maxfd) {
+
+ int listensock; /* listening fd */
+ struct sockaddr_in listen_addr;
+ struct linger linger;
+ unsigned int i;
+ int val;
+
+ for (i = 0; i < svr_opts.portcount; i++) {
+
+ /* iterate through all the sockets to listen on */
+ listensock = socket(PF_INET, SOCK_STREAM, 0);
+ if (listensock < 0) {
+ dropbear_exit("Failed to create socket");
+ }
+
+ val = 1;
+ /* set to reuse, quick timeout */
+ setsockopt(listensock, SOL_SOCKET, SO_REUSEADDR,
+ (void*) &val, sizeof(val));
+ linger.l_onoff = 1;
+ linger.l_linger = 5;
+ setsockopt(listensock, SOL_SOCKET, SO_LINGER,
+ (void*)&linger, sizeof(linger));
+
+ /* disable nagle */
+ setsockopt(listensock, IPPROTO_TCP, TCP_NODELAY,
+ (void*)&val, sizeof(val));
+
+ memset((void*)&listen_addr, 0x0, sizeof(listen_addr));
+ listen_addr.sin_family = AF_INET;
+ listen_addr.sin_port = htons(svr_opts.ports[i]);
+ listen_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+ memset(&(listen_addr.sin_zero), '\0', 8);
+
+ if (bind(listensock, (struct sockaddr *)&listen_addr,
+ sizeof(listen_addr)) < 0) {
+ dropbear_exit("Bind failed port %d", svr_opts.ports[i]);
+ }
+
+ /* listen */
+ if (listen(listensock, 20) < 0) { /* TODO set listen count */
+ dropbear_exit("Listen failed");
+ }
+
+ /* nonblock */
+ if (fcntl(listensock, F_SETFL, O_NONBLOCK) < 0) {
+ dropbear_exit("Failed to set non-blocking");
+ }
+
+ sock[i] = listensock;
+ *maxfd = MAX(listensock, *maxfd);
+ }
+
+ return svr_opts.portcount;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-02-22 23:09:23 +0000