]> andersk Git - openssh.git/blobdiff - sshd.c
- (djm) Merged big SCO portability patch from Tim Rice
[openssh.git] / sshd.c
diff --git a/sshd.c b/sshd.c
index cc6bee96a9c101ba3aa1a570e3ab82ecc1c4c4d7..7fed51c4257d437414b70b6db392b078e22bac63 100644 (file)
--- a/sshd.c
+++ b/sshd.c
@@ -2,19 +2,45 @@
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
- * Created: Fri Mar 17 17:09:28 1995 ylo
- * This program is the ssh daemon.  It listens for connections from clients, and
- * performs authentication, executes use commands or shell, and forwards
+ * This program is the ssh daemon.  It listens for connections from clients,
+ * and performs authentication, executes use commands or shell, and forwards
  * information to/from the application to the user client over an encrypted
- * connection.  This can also handle forwarding of X11, TCP/IP, and authentication
- * agent connections.
+ * connection.  This can also handle forwarding of X11, TCP/IP, and
+ * authentication agent connections.
  *
- * SSH2 implementation,
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ * SSH2 implementation:
+ *
+ * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.105 2000/04/14 10:30:33 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.128 2000/09/17 15:38:59 markus Exp $");
 
 #include "xmalloc.h"
 #include "rsa.h"
@@ -29,26 +55,18 @@ RCSID("$OpenBSD: sshd.c,v 1.105 2000/04/14 10:30:33 markus Exp $");
 #include "buffer.h"
 
 #include "ssh2.h"
-#ifdef HAVE_OPENSSL
-# include <openssl/dh.h>
-# include <openssl/bn.h>
-# include <openssl/hmac.h>
-# include <openssl/dsa.h>
-# include <openssl/rsa.h>
-#endif
-#ifdef HAVE_SSL
-# include <ssl/dh.h>
-# include <ssl/bn.h>
-# include <ssl/hmac.h>
-# include <ssl/dsa.h>
-# include <ssl/rsa.h>
-#endif
+#include <openssl/dh.h>
+#include <openssl/bn.h>
+#include <openssl/hmac.h>
 #include "kex.h"
+#include <openssl/dsa.h>
+#include <openssl/rsa.h>
 #include "key.h"
 #include "dsa.h"
 
 #include "auth.h"
 #include "myproposal.h"
+#include "authfile.h"
 
 #ifdef LIBWRAP
 #include <tcpd.h>
@@ -96,6 +114,7 @@ char *av0;
 
 /* Saved arguments to main(). */
 char **saved_argv;
+int saved_argc;
 
 /*
  * The sockets that the server is listening; this is used in the SIGHUP
@@ -121,8 +140,9 @@ char *server_version_string = NULL;
  * not very useful.  Currently, memory locking is not implemented.
  */
 struct {
-       RSA *private_key;        /* Private part of server key. */
+       RSA *private_key;        /* Private part of empheral server key. */
        RSA *host_key;           /* Private part of host key. */
+       Key *dsa_host_key;       /* Private DSA host key. */
 } sensitive_data;
 
 /*
@@ -141,6 +161,13 @@ RSA *public_key;
 /* session identifier, used by RSA-auth */
 unsigned char session_id[16];
 
+/* same for ssh2 */
+unsigned char *session_id2 = NULL;
+int session_id2_len = 0;
+
+/* record remote hostname or ip */
+unsigned int utmp_len = MAXHOSTNAMELEN;
+
 /* Prototypes for various functions defined later in this file. */
 void do_ssh1_kex();
 void do_ssh2_kex();
@@ -193,6 +220,7 @@ sigterm_handler(int sig)
 {
        log("Received signal %d; terminating.", sig);
        close_listen_socks();
+       unlink(options.pid_file);
        exit(255);
 }
 
@@ -233,6 +261,7 @@ grace_alarm_handler(int sig)
  * Thus there should be no concurrency control/asynchronous execution
  * problems.
  */
+/* XXX do we really want this work to be done in a signal handler ? -m */
 void
 key_regeneration_alarm(int sig)
 {
@@ -263,21 +292,6 @@ key_regeneration_alarm(int sig)
        errno = save_errno;
 }
 
-char *
-chop(char *s)
-{
-       char *t = s;
-       while (*t) {
-               if(*t == '\n' || *t == '\r') {
-                       *t = '\0';
-                       return s;
-               }
-               t++;
-       }
-       return s;
-
-}
-
 void
 sshd_exchange_identification(int sock_in, int sock_out)
 {
@@ -312,7 +326,7 @@ sshd_exchange_identification(int sock_in, int sock_out)
 
                /* Read other side\'s version identification. */
                for (i = 0; i < sizeof(buf) - 1; i++) {
-                       if (read(sock_in, &buf[i], 1) != 1) {
+                       if (atomicio(read, sock_in, &buf[i], 1) != 1) {
                                log("Did not receive ident string from %s.", get_remote_ipaddr());
                                fatal_cleanup();
                        }
@@ -353,23 +367,24 @@ sshd_exchange_identification(int sock_in, int sock_out)
        mismatch = 0;
        switch(remote_major) {
        case 1:
+               if (remote_minor == 99) {
+                       if (options.protocol & SSH_PROTO_2)
+                               enable_compat20();
+                       else
+                               mismatch = 1;
+                       break;
+               }
                if (!(options.protocol & SSH_PROTO_1)) {
                        mismatch = 1;
                        break;
                }
                if (remote_minor < 3) {
-                       packet_disconnect("Your ssh version is too old and"
+                       packet_disconnect("Your ssh version is too old and "
                            "is no longer supported.  Please install a newer version.");
                } else if (remote_minor == 3) {
                        /* note that this disables agent-forwarding */
                        enable_compat13();
                }
-               if (remote_minor == 99) {
-                       if (options.protocol & SSH_PROTO_2)
-                               enable_compat20();
-                       else
-                               mismatch = 1;
-               }
                break;
        case 2:
                if (options.protocol & SSH_PROTO_2) {
@@ -395,8 +410,57 @@ sshd_exchange_identification(int sock_in, int sock_out)
                    server_version_string, client_version_string);
                fatal_cleanup();
        }
+       if (compat20)
+               packet_set_ssh2_format();
+}
+
+
+void
+destroy_sensitive_data(void)
+{
+       /* Destroy the private and public keys.  They will no longer be needed. */
+       if (public_key)
+               RSA_free(public_key);
+       if (sensitive_data.private_key)
+               RSA_free(sensitive_data.private_key);
+       if (sensitive_data.host_key)
+               RSA_free(sensitive_data.host_key);
+       if (sensitive_data.dsa_host_key != NULL)
+               key_free(sensitive_data.dsa_host_key);
 }
 
+/*
+ * returns 1 if connection should be dropped, 0 otherwise.
+ * dropping starts at connection #max_startups_begin with a probability
+ * of (max_startups_rate/100). the probability increases linearly until
+ * all connections are dropped for startups > max_startups
+ */
+int
+drop_connection(int startups)
+{
+       double p, r;
+
+       if (startups < options.max_startups_begin)
+               return 0;
+       if (startups >= options.max_startups)
+               return 1;
+       if (options.max_startups_rate == 100)
+               return 1;
+
+       p  = 100 - options.max_startups_rate;
+       p *= startups - options.max_startups_begin;
+       p /= (double) (options.max_startups - options.max_startups_begin);
+       p += options.max_startups_rate;
+       p /= 100.0;
+       r = arc4random() / (double) UINT_MAX;
+
+       debug("drop_connection: p %g, r %g", p, r);
+       return (r < p) ? 1 : 0;
+}
+
+int *startup_pipes = NULL;     /* options.max_startup sized array of fd ints */
+int startup_pipe;              /* in child */
+
 /*
  * Main program for the daemon.
  */
@@ -405,21 +469,26 @@ main(int ac, char **av)
 {
        extern char *optarg;
        extern int optind;
-       int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
+       int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
+       pid_t pid;
        socklen_t fromlen;
-       int silentrsa = 0;
+       int silent = 0;
        fd_set *fdset;
        struct sockaddr_storage from;
        const char *remote_ip;
        int remote_port;
-       char *comment;
        FILE *f;
        struct linger linger;
        struct addrinfo *ai;
        char ntop[NI_MAXHOST], strport[NI_MAXSERV];
        int listen_sock, maxfd;
+       int startup_p[2];
+       int startups = 0;
+
+       init_rng();
 
        /* Save argv[0]. */
+       saved_argc = ac;
        saved_argv = av;
        if (strchr(av[0], '/'))
                av0 = strrchr(av[0], '/') + 1;
@@ -430,7 +499,7 @@ main(int ac, char **av)
        initialize_server_options(&options);
 
        /* Parse command-line arguments. */
-       while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
+       while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:diqQ46")) != EOF) {
                switch (opt) {
                case '4':
                        IPv4or6 = AF_INET;
@@ -442,14 +511,21 @@ main(int ac, char **av)
                        config_file_name = optarg;
                        break;
                case 'd':
-                       debug_flag = 1;
-                       options.log_level = SYSLOG_LEVEL_DEBUG;
+                       if (0 == debug_flag) {
+                               debug_flag = 1;
+                               options.log_level = SYSLOG_LEVEL_DEBUG1;
+                       } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
+                               options.log_level++;
+                       } else {
+                               fprintf(stderr, "Too high debugging level.\n");
+                               exit(1);
+                       }
                        break;
                case 'i':
                        inetd_flag = 1;
                        break;
                case 'Q':
-                       silentrsa = 1;
+                       silent = 1;
                        break;
                case 'q':
                        options.log_level = SYSLOG_LEVEL_QUIET;
@@ -459,8 +535,10 @@ main(int ac, char **av)
                        break;
                case 'p':
                        options.ports_from_cmdline = 1;
-                       if (options.num_ports >= MAX_PORTS)
-                               fatal("too many ports.\n");
+                       if (options.num_ports >= MAX_PORTS) {
+                               fprintf(stderr, "too many ports.\n");
+                               exit(1);
+                       }
                        options.ports[options.num_ports++] = atoi(optarg);
                        break;
                case 'g':
@@ -477,13 +555,16 @@ main(int ac, char **av)
                        /* only makes sense with inetd_flag, i.e. no listen() */
                        inetd_flag = 1;
                        break;
+               case 'u':
+                       utmp_len = atoi(optarg);
+                       break;
                case '?':
                default:
                        fprintf(stderr, "sshd version %s\n", SSH_VERSION);
                        fprintf(stderr, "Usage: %s [options]\n", av0);
                        fprintf(stderr, "Options:\n");
                        fprintf(stderr, "  -f file    Configuration file (default %s)\n", SERVER_CONFIG_FILE);
-                       fprintf(stderr, "  -d         Debugging mode\n");
+                       fprintf(stderr, "  -d         Debugging mode (multiple -d means more debugging)\n");
                        fprintf(stderr, "  -i         Started from inetd\n");
                        fprintf(stderr, "  -q         Quiet (no logging)\n");
                        fprintf(stderr, "  -p port    Listen on the specified port (default: 22)\n");
@@ -492,6 +573,7 @@ main(int ac, char **av)
                        fprintf(stderr, "  -b bits    Size of server RSA key (default: 768 bits)\n");
                        fprintf(stderr, "  -h file    File from which to read host key (default: %s)\n",
                            HOST_KEY_FILE);
+                       fprintf(stderr, "  -u len     Maximum hostname length for utmp recording\n");
                        fprintf(stderr, "  -4         Use IPv4 only\n");
                        fprintf(stderr, "  -6         Use IPv6 only\n");
                        exit(1);
@@ -505,27 +587,14 @@ main(int ac, char **av)
        log_init(av0,
            options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
            options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
-           !inetd_flag);
+           !silent && !inetd_flag);
 
-       /* check if RSA support exists */
-       if (rsa_alive() == 0) {
-               if (silentrsa == 0)
-                       printf("sshd: no RSA support in libssl and libcrypto -- exiting.  See ssl(8)\n");
-               log("no RSA support in libssl and libcrypto -- exiting.  See ssl(8)");
-               exit(1);
-       }
        /* Read server configuration options from the configuration file. */
        read_server_config(&options, config_file_name);
 
        /* Fill in default values for those options not explicitly set. */
        fill_default_server_options(&options);
 
-       /* Check certain values for sanity. */
-       if (options.server_key_bits < 512 ||
-           options.server_key_bits > 32768) {
-               fprintf(stderr, "Bad server key size.\n");
-               exit(1);
-       }
        /* Check that there are no remaining arguments. */
        if (optind < ac) {
                fprintf(stderr, "Extra argument %s.\n", av[optind]);
@@ -534,26 +603,84 @@ main(int ac, char **av)
 
        debug("sshd version %.100s", SSH_VERSION);
 
-       sensitive_data.host_key = RSA_new();
-       errno = 0;
-       /* Load the host key.  It must have empty passphrase. */
-       if (!load_private_key(options.host_key_file, "",
-                             sensitive_data.host_key, &comment)) {
-               error("Could not load host key: %.200s: %.100s",
-                     options.host_key_file, strerror(errno));
+       sensitive_data.dsa_host_key = NULL;
+       sensitive_data.host_key = NULL;
+
+       /* check if RSA support exists */
+       if ((options.protocol & SSH_PROTO_1) &&
+           rsa_alive() == 0) {
+               log("no RSA support in libssl and libcrypto.  See ssl(8)");
+               log("Disabling protocol version 1");
+               options.protocol &= ~SSH_PROTO_1;
+       }
+       /* Load the RSA/DSA host key.  It must have empty passphrase. */
+       if (options.protocol & SSH_PROTO_1) {
+               Key k;
+               sensitive_data.host_key = RSA_new();
+               k.type = KEY_RSA;
+               k.rsa = sensitive_data.host_key;
+               errno = 0;
+               if (!load_private_key(options.host_key_file, "", &k, NULL)) {
+                       error("Could not load host key: %.200s: %.100s",
+                           options.host_key_file, strerror(errno));
+                       log("Disabling protocol version 1");
+                       options.protocol &= ~SSH_PROTO_1;
+               }
+               k.rsa = NULL;
+       }
+       if (options.protocol & SSH_PROTO_2) {
+               sensitive_data.dsa_host_key = key_new(KEY_DSA);
+               if (!load_private_key(options.host_dsa_key_file, "", sensitive_data.dsa_host_key, NULL)) {
+
+                       error("Could not load DSA host key: %.200s", options.host_dsa_key_file);
+                       log("Disabling protocol version 2");
+                       options.protocol &= ~SSH_PROTO_2;
+               }
+       }
+       if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
+               if (silent == 0)
+                       fprintf(stderr, "sshd: no hostkeys available -- exiting.\n");
+               log("sshd: no hostkeys available -- exiting.\n");
                exit(1);
        }
-       xfree(comment);
 
-       /* Initialize the log (it is reinitialized below in case we
-          forked). */
+       /* Check certain values for sanity. */
+       if (options.protocol & SSH_PROTO_1) {
+               if (options.server_key_bits < 512 ||
+                   options.server_key_bits > 32768) {
+                       fprintf(stderr, "Bad server key size.\n");
+                       exit(1);
+               }
+               /*
+                * Check that server and host key lengths differ sufficiently. This
+                * is necessary to make double encryption work with rsaref. Oh, I
+                * hate software patents. I dont know if this can go? Niels
+                */
+               if (options.server_key_bits >
+                   BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
+                   options.server_key_bits <
+                   BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
+                       options.server_key_bits =
+                           BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
+                       debug("Forcing server key to %d bits to make it differ from host key.",
+                           options.server_key_bits);
+               }
+       }
+
+#ifdef HAVE_SCO_PROTECTED_PW
+       (void) set_auth_parameters(ac, av);
+#endif
+
+       /* Initialize the log (it is reinitialized below in case we forked). */
        if (debug_flag && !inetd_flag)
                log_stderr = 1;
        log_init(av0, options.log_level, options.log_facility, log_stderr);
 
-       /* If not in debugging mode, and not started from inetd,
-          disconnect from the controlling terminal, and fork.  The
-          original process exits. */
+       /*
+        * If not in debugging mode, and not started from inetd, disconnect
+        * from the controlling terminal, and fork.  The original process
+        * exits.
+        */
        if (!debug_flag && !inetd_flag) {
 #ifdef TIOCNOTTY
                int fd;
@@ -573,18 +700,6 @@ main(int ac, char **av)
        /* Reinitialize the log (because of the fork above). */
        log_init(av0, options.log_level, options.log_facility, log_stderr);
 
-       /* Check that server and host key lengths differ sufficiently.
-          This is necessary to make double encryption work with rsaref.
-          Oh, I hate software patents. I dont know if this can go? Niels */
-       if (options.server_key_bits >
-       BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
-           options.server_key_bits <
-       BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
-               options.server_key_bits =
-                       BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
-               debug("Forcing server key to %d bits to make it differ from host key.",
-                     options.server_key_bits);
-       }
        /* Do not display messages to stdout in RSA code. */
        rsa_set_verbose(0);
 
@@ -602,20 +717,23 @@ main(int ac, char **av)
                s2 = dup(s1);
                sock_in = dup(0);
                sock_out = dup(1);
-               /* We intentionally do not close the descriptors 0, 1, and 2
-                  as our code for setting the descriptors won\'t work
-                  if ttyfd happens to be one of those. */
+               startup_pipe = -1;
+               /*
+                * We intentionally do not close the descriptors 0, 1, and 2
+                * as our code for setting the descriptors won\'t work if
+                * ttyfd happens to be one of those.
+                */
                debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
 
-               public_key = RSA_new();
-               sensitive_data.private_key = RSA_new();
-
-               /* XXX check options.protocol */
-               log("Generating %d bit RSA key.", options.server_key_bits);
-               rsa_generate_key(sensitive_data.private_key, public_key,
-                                options.server_key_bits);
-               arc4random_stir();
-               log("RSA key generation complete.");
+               if (options.protocol & SSH_PROTO_1) {
+                       public_key = RSA_new();
+                       sensitive_data.private_key = RSA_new();
+                       log("Generating %d bit RSA key.", options.server_key_bits);
+                       rsa_generate_key(sensitive_data.private_key, public_key,
+                           options.server_key_bits);
+                       arc4random_stir();
+                       log("RSA key generation complete.");
+               }
        } else {
                for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
                        if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
@@ -686,28 +804,30 @@ main(int ac, char **av)
                         * fail if there already is a daemon, and this will
                         * overwrite any old pid in the file.
                         */
-                       f = fopen(SSH_DAEMON_PID_FILE, "w");
+                       f = fopen(options.pid_file, "wb");
                        if (f) {
                                fprintf(f, "%u\n", (unsigned int) getpid());
                                fclose(f);
                        }
                }
+               if (options.protocol & SSH_PROTO_1) {
+                       public_key = RSA_new();
+                       sensitive_data.private_key = RSA_new();
 
-               public_key = RSA_new();
-               sensitive_data.private_key = RSA_new();
-
-               log("Generating %d bit RSA key.", options.server_key_bits);
-               rsa_generate_key(sensitive_data.private_key, public_key,
-                                options.server_key_bits);
-               arc4random_stir();
-               log("RSA key generation complete.");
+                       log("Generating %d bit RSA key.", options.server_key_bits);
+                       rsa_generate_key(sensitive_data.private_key, public_key,
+                           options.server_key_bits);
+                       arc4random_stir();
+                       log("RSA key generation complete.");
 
-               /* Schedule server key regeneration alarm. */
-               signal(SIGALRM, key_regeneration_alarm);
-               alarm(options.key_regeneration_time);
+                       /* Schedule server key regeneration alarm. */
+                       signal(SIGALRM, key_regeneration_alarm);
+                       alarm(options.key_regeneration_time);
+               }
 
                /* Arrange to restart on SIGHUP.  The handler needs listen_sock. */
                signal(SIGHUP, sighup_handler);
+
                signal(SIGTERM, sigterm_handler);
                signal(SIGQUIT, sigterm_handler);
 
@@ -715,12 +835,15 @@ main(int ac, char **av)
                signal(SIGCHLD, main_sigchld_handler);
 
                /* setup fd set for listen */
+               fdset = NULL;
                maxfd = 0;
                for (i = 0; i < num_listen_socks; i++)
                        if (listen_socks[i] > maxfd)
                                maxfd = listen_socks[i];
-               fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
-               fdset = (fd_set *)xmalloc(fdsetsz);
+               /* pipes connected to unauthenticated childs */
+               startup_pipes = xmalloc(options.max_startups * sizeof(int));
+               for (i = 0; i < options.max_startups; i++)
+                       startup_pipes[i] = -1;
 
                /*
                 * Stay listening for connections until the system crashes or
@@ -729,80 +852,130 @@ main(int ac, char **av)
                for (;;) {
                        if (received_sighup)
                                sighup_restart();
-                       /* Wait in select until there is a connection. */
+                       if (fdset != NULL)
+                               xfree(fdset);
+                       fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
+                       fdset = (fd_set *)xmalloc(fdsetsz);
                        memset(fdset, 0, fdsetsz);
+
                        for (i = 0; i < num_listen_socks; i++)
                                FD_SET(listen_socks[i], fdset);
+                       for (i = 0; i < options.max_startups; i++)
+                               if (startup_pipes[i] != -1)
+                                       FD_SET(startup_pipes[i], fdset);
+
+                       /* Wait in select until there is a connection. */
                        if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
                                if (errno != EINTR)
                                        error("select: %.100s", strerror(errno));
                                continue;
                        }
+                       for (i = 0; i < options.max_startups; i++)
+                               if (startup_pipes[i] != -1 &&
+                                   FD_ISSET(startup_pipes[i], fdset)) {
+                                       /*
+                                        * the read end of the pipe is ready
+                                        * if the child has closed the pipe
+                                        * after successfull authentication
+                                        * or if the child has died
+                                        */
+                                       close(startup_pipes[i]);
+                                       startup_pipes[i] = -1;
+                                       startups--;
+                               }
                        for (i = 0; i < num_listen_socks; i++) {
                                if (!FD_ISSET(listen_socks[i], fdset))
                                        continue;
-                       fromlen = sizeof(from);
-                       newsock = accept(listen_socks[i], (struct sockaddr *)&from,
-                           &fromlen);
-                       if (newsock < 0) {
-                               if (errno != EINTR && errno != EWOULDBLOCK)
-                                       error("accept: %.100s", strerror(errno));
-                               continue;
-                       }
-                       if (fcntl(newsock, F_SETFL, 0) < 0) {
-                               error("newsock del O_NONBLOCK: %s", strerror(errno));
-                               continue;
-                       }
-                       /*
-                        * Got connection.  Fork a child to handle it, unless
-                        * we are in debugging mode.
-                        */
-                       if (debug_flag) {
-                               /*
-                                * In debugging mode.  Close the listening
-                                * socket, and start processing the
-                                * connection without forking.
-                                */
-                               debug("Server will not fork when running in debugging mode.");
-                               close_listen_socks();
-                               sock_in = newsock;
-                               sock_out = newsock;
-                               pid = getpid();
-                               break;
-                       } else {
+                               fromlen = sizeof(from);
+                               newsock = accept(listen_socks[i], (struct sockaddr *)&from,
+                                   &fromlen);
+                               if (newsock < 0) {
+                                       if (errno != EINTR && errno != EWOULDBLOCK)
+                                               error("accept: %.100s", strerror(errno));
+                                       continue;
+                               }
+                               if (fcntl(newsock, F_SETFL, 0) < 0) {
+                                       error("newsock del O_NONBLOCK: %s", strerror(errno));
+                                       continue;
+                               }
+                               if (drop_connection(startups) == 1) {
+                                       debug("drop connection #%d", startups);
+                                       close(newsock);
+                                       continue;
+                               }
+                               if (pipe(startup_p) == -1) {
+                                       close(newsock);
+                                       continue;
+                               }
+
+                               for (j = 0; j < options.max_startups; j++)
+                                       if (startup_pipes[j] == -1) {
+                                               startup_pipes[j] = startup_p[0];
+                                               if (maxfd < startup_p[0])
+                                                       maxfd = startup_p[0];
+                                               startups++;
+                                               break;
+                                       }
+                               
                                /*
-                                * Normal production daemon.  Fork, and have
-                                * the child process the connection. The
-                                * parent continues listening.
+                                * Got connection.  Fork a child to handle it, unless
+                                * we are in debugging mode.
                                 */
-                               if ((pid = fork()) == 0) {
+                               if (debug_flag) {
                                        /*
-                                        * Child.  Close the listening socket, and start using the
-                                        * accepted socket.  Reinitialize logging (since our pid has
-                                        * changed).  We break out of the loop to handle the connection.
+                                        * In debugging mode.  Close the listening
+                                        * socket, and start processing the
+                                        * connection without forking.
                                         */
+                                       debug("Server will not fork when running in debugging mode.");
                                        close_listen_socks();
                                        sock_in = newsock;
                                        sock_out = newsock;
-                                       log_init(av0, options.log_level, options.log_facility, log_stderr);
+                                       startup_pipe = -1;
+                                       pid = getpid();
                                        break;
+                               } else {
+                                       /*
+                                        * Normal production daemon.  Fork, and have
+                                        * the child process the connection. The
+                                        * parent continues listening.
+                                        */
+                                       if ((pid = fork()) == 0) {
+                                               /*
+                                                * Child.  Close the listening and max_startup
+                                                * sockets.  Start using the accepted socket.
+                                                * Reinitialize logging (since our pid has
+                                                * changed).  We break out of the loop to handle
+                                                * the connection.
+                                                */
+                                               startup_pipe = startup_p[1];
+                                               for (j = 0; j < options.max_startups; j++)
+                                                       if (startup_pipes[j] != -1)
+                                                               close(startup_pipes[j]);
+                                               close_listen_socks();
+                                               sock_in = newsock;
+                                               sock_out = newsock;
+                                               log_init(av0, options.log_level, options.log_facility, log_stderr);
+                                               break;
+                                       }
                                }
-                       }
 
-                       /* Parent.  Stay in the loop. */
-                       if (pid < 0)
-                               error("fork: %.100s", strerror(errno));
-                       else
-                               debug("Forked child %d.", pid);
+                               /* Parent.  Stay in the loop. */
+                               if (pid < 0)
+                                       error("fork: %.100s", strerror(errno));
+                               else
+                                       debug("Forked child %d.", pid);
 
-                       /* Mark that the key has been used (it was "given" to the child). */
-                       key_used = 1;
+                               close(startup_p[1]);
 
-                       arc4random_stir();
+                               /* Mark that the key has been used (it was "given" to the child). */
+                               key_used = 1;
+
+                               arc4random_stir();
 
-                       /* Close the new socket (the child is now taking care of it). */
-                       close(newsock);
-                       } /* for (i = 0; i < num_listen_socks; i++) */
+                               /* Close the new socket (the child is now taking care of it). */
+                               close(newsock);
+                       }
                        /* child process check (or debug mode) */
                        if (num_listen_socks < 0)
                                break;
@@ -822,6 +995,7 @@ main(int ac, char **av)
        signal(SIGTERM, SIG_DFL);
        signal(SIGQUIT, SIG_DFL);
        signal(SIGCHLD, SIG_DFL);
+       signal(SIGINT, SIG_DFL);
 
        /*
         * Set socket options for the connection.  We want the socket to
@@ -1077,9 +1251,7 @@ do_ssh1_kex()
                           sensitive_data.private_key->n);
 
        /* Destroy the private and public keys.  They will no longer be needed. */
-       RSA_free(public_key);
-       RSA_free(sensitive_data.private_key);
-       RSA_free(sensitive_data.host_key);
+       destroy_sensitive_data();
 
        /*
         * Extract session key from the decrypted integer.  The key is in the
@@ -1127,7 +1299,6 @@ do_ssh2_kex()
        int payload_len, dlen;
        int slen;
        unsigned int klen, kout;
-       char *ptr;
        unsigned char *signature = NULL;
        unsigned char *server_host_key_blob = NULL;
        unsigned int sbloblen;
@@ -1138,9 +1309,7 @@ do_ssh2_kex()
        unsigned char *kbuf;
        unsigned char *hash;
        Kex *kex;
-       Key *server_host_key;
        char *cprop[PROPOSAL_MAX];
-       char *sprop[PROPOSAL_MAX];
 
 /* KEXINIT */
 
@@ -1148,46 +1317,15 @@ do_ssh2_kex()
                myproposal[PROPOSAL_ENC_ALGS_CTOS] =
                myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
        }
-
-       debug("Sending KEX init.");
-
-       for (i = 0; i < PROPOSAL_MAX; i++)
-               sprop[i] = xstrdup(myproposal[i]);
-       server_kexinit = kex_init(sprop);
-       packet_start(SSH2_MSG_KEXINIT);
-       packet_put_raw(buffer_ptr(server_kexinit), buffer_len(server_kexinit)); 
-       packet_send();
-       packet_write_wait();
-
-       debug("done");
-
-       packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
-
-       /*
-        * save raw KEXINIT payload in buffer. this is used during
-        * computation of the session_id and the session keys.
-        */
+       server_kexinit = kex_init(myproposal);
        client_kexinit = xmalloc(sizeof(*client_kexinit));
        buffer_init(client_kexinit);
-       ptr = packet_get_raw(&payload_len);
-       buffer_append(client_kexinit, ptr, payload_len);
-
-       /* skip cookie */
-       for (i = 0; i < 16; i++)
-               (void) packet_get_char();
-       /* save kex init proposal strings */
-       for (i = 0; i < PROPOSAL_MAX; i++) {
-               cprop[i] = packet_get_string(NULL);
-               debug("got kexinit string: %s", cprop[i]);
-       }
 
-       i = (int) packet_get_char();
-       debug("first kex follow == %d", i);
-       i = packet_get_int();
-       debug("reserved == %d", i);
-
-       debug("done read kexinit");
-       kex = kex_choose_conf(cprop, sprop, 1);
+       /* algorithm negotiation */
+       kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
+       kex = kex_choose_conf(cprop, myproposal, 1);
+       for (i = 0; i < PROPOSAL_MAX; i++)
+               xfree(cprop[i]);
 
 /* KEXDH */
 
@@ -1202,7 +1340,7 @@ do_ssh2_kex()
 
 #ifdef DEBUG_KEXDH
        fprintf(stderr, "\ndh_client_pub= ");
-       bignum_print(dh_client_pub);
+       BN_print_fp(stderr, dh_client_pub);
        fprintf(stderr, "\n");
        debug("bits %d", BN_num_bits(dh_client_pub));
 #endif
@@ -1212,12 +1350,13 @@ do_ssh2_kex()
 
 #ifdef DEBUG_KEXDH
        fprintf(stderr, "\np= ");
-       bignum_print(dh->p);
+       BN_print_fp(stderr, dh->p);
        fprintf(stderr, "\ng= ");
-       bignum_print(dh->g);
+       bn_print(dh->g);
        fprintf(stderr, "\npub= ");
-       bignum_print(dh->pub_key);
+       BN_print_fp(stderr, dh->pub_key);
        fprintf(stderr, "\n");
+        DHparams_print_fp(stderr, dh);
 #endif
        if (!dh_pub_is_valid(dh, dh_client_pub))
                packet_disconnect("bad client public DH value");
@@ -1239,8 +1378,8 @@ do_ssh2_kex()
        memset(kbuf, 0, klen);
        xfree(kbuf);
 
-       server_host_key = dsa_get_serverkey(options.dsa_key_file);
-       dsa_make_serverkey_blob(server_host_key, &server_host_key_blob, &sbloblen);
+       /* XXX precompute? */
+       dsa_make_key_blob(sensitive_data.dsa_host_key, &server_host_key_blob, &sbloblen);
 
        /* calc H */                    /* XXX depends on 'kex' */
        hash = kex_hash(
@@ -1263,17 +1402,26 @@ do_ssh2_kex()
                fprintf(stderr, "%02x", (hash[i])&0xff);
        fprintf(stderr, "\n");
 #endif
+       /* save session id := H */
+       /* XXX hashlen depends on KEX */
+       session_id2_len = 20;
+       session_id2 = xmalloc(session_id2_len);
+       memcpy(session_id2, hash, session_id2_len);
+
        /* sign H */
-       dsa_sign(server_host_key, &signature, &slen, hash, 20);
-               /* hashlen depends on KEX */
-       key_free(server_host_key);
+       /* XXX hashlen depends on KEX */
+       dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20);
+
+       destroy_sensitive_data();
 
        /* send server hostkey, DH pubkey 'f' and singed H */
        packet_start(SSH2_MSG_KEXDH_REPLY);
        packet_put_string((char *)server_host_key_blob, sbloblen);
-       packet_put_bignum2(dh->pub_key);        // f
+       packet_put_bignum2(dh->pub_key);        /* f */
        packet_put_string((char *)signature, slen);
        packet_send();
+       xfree(signature);
+       xfree(server_host_key_blob);
        packet_write_wait();
 
        kex_derive_keys(kex, hash, shared_secret);
This page took 0.085174 seconds and 4 git commands to generate.