]> andersk Git - gssapi-openssh.git/blobdiff - openssh/session.c
merged OpenSSH 5.3p1 to trunk
[gssapi-openssh.git] / openssh / session.c
index a23ae9dbc47269d3b590bc97e575b392de5e2330..52a8a0be53c7e2cd5f298650555350e5f5c0118b 100644 (file)
@@ -1,3 +1,4 @@
+/* $OpenBSD: session.c,v 1.246 2009/04/17 19:23:06 stevesk Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.150 2002/09/16 19:55:33 stevesk Exp $");
 
+#include <sys/types.h>
+#include <sys/param.h>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <grp.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "openbsd-compat/sys-queue.h"
+#include "xmalloc.h"
 #include "ssh.h"
 #include "ssh1.h"
 #include "ssh2.h"
-#include "xmalloc.h"
 #include "sshpty.h"
 #include "packet.h"
 #include "buffer.h"
-#include "mpaux.h"
+#include "match.h"
 #include "uidswap.h"
 #include "compat.h"
 #include "channels.h"
-#include "bufaux.h"
+#include "key.h"
+#include "cipher.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "hostfile.h"
 #include "auth.h"
 #include "auth-options.h"
 #include "pathnames.h"
@@ -55,29 +85,32 @@ RCSID("$OpenBSD: session.c,v 1.150 2002/09/16 19:55:33 stevesk Exp $");
 #include "sshlogin.h"
 #include "serverloop.h"
 #include "canohost.h"
+#include "misc.h"
 #include "session.h"
+#include "kex.h"
 #include "monitor_wrap.h"
+#include "sftp.h"
 
-#ifdef GSSAPI
-#include "ssh-gss.h"
+#if defined(KRB5) && defined(USE_AFS)
+#include <kafs.h>
 #endif
 
-#ifdef HAVE_CYGWIN
-#include <windows.h>
-#include <sys/cygwin.h>
-#define is_winnt       (GetVersion() < 0x80000000)
-#endif
+#define IS_INTERNAL_SFTP(c) \
+       (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
+        (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
+         c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
+         c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
 
 /* func */
 
 Session *session_new(void);
-void   session_set_fds(Session *, int, int, int);
-void   session_pty_cleanup(void *);
+void   session_set_fds(Session *, int, int, int, int);
+void   session_pty_cleanup(Session *);
 void   session_proctitle(Session *);
 int    session_setup_x11fwd(Session *);
-void   do_exec_pty(Session *, const char *);
-void   do_exec_no_pty(Session *, const char *);
-void   do_exec(Session *, const char *);
+int    do_exec_pty(Session *, const char *);
+int    do_exec_no_pty(Session *, const char *);
+int    do_exec(Session *, const char *);
 void   do_login(Session *, const char *);
 #ifdef LOGIN_NEEDS_UTMPX
 static void    do_pre_login(Session *s);
@@ -91,6 +124,11 @@ static void do_authenticated2(Authctxt *);
 
 static int session_pty_req(Session *);
 
+#ifdef SESSION_HOOKS
+static void execute_session_hook(char* prog, Authctxt *authctxt,
+                                 int startup, int save);
+#endif
+
 /* import */
 extern ServerOptions options;
 extern char *__progname;
@@ -99,22 +137,26 @@ extern int debug_flag;
 extern u_int utmp_len;
 extern int startup_pipe;
 extern void destroy_sensitive_data(void);
+extern Buffer loginmsg;
 
 /* original command from peer. */
 const char *original_command = NULL;
 
 /* data */
-#define MAX_SESSIONS 10
-Session        sessions[MAX_SESSIONS];
+static int sessions_first_unused = -1;
+static int sessions_nalloc = 0;
+static Session *sessions = NULL;
 
-#ifdef WITH_AIXAUTHENTICATE
-char *aixloginmsg;
-#endif /* WITH_AIXAUTHENTICATE */
+#define SUBSYSTEM_NONE         0
+#define SUBSYSTEM_EXT          1
+#define SUBSYSTEM_INT_SFTP     2
 
 #ifdef HAVE_LOGIN_CAP
 login_cap_t *lc;
 #endif
 
+static int is_child = 0;
+
 /* Name and directory of socket for authentication agent forwarding. */
 static char *auth_sock_name = NULL;
 static char *auth_sock_dir = NULL;
@@ -122,10 +164,8 @@ static char *auth_sock_dir = NULL;
 /* removes the agent forwarding socket */
 
 static void
-auth_sock_cleanup_proc(void *_pw)
+auth_sock_cleanup_proc(struct passwd *pw)
 {
-       struct passwd *pw = _pw;
-
        if (auth_sock_name != NULL) {
                temporarily_use_uid(pw);
                unlink(auth_sock_name);
@@ -139,7 +179,7 @@ static int
 auth_input_request_forwarding(struct passwd * pw)
 {
        Channel *nc;
-       int sock;
+       int sock = -1;
        struct sockaddr_un sunaddr;
 
        if (auth_sock_name != NULL) {
@@ -151,69 +191,86 @@ auth_input_request_forwarding(struct passwd * pw)
        temporarily_use_uid(pw);
 
        /* Allocate a buffer for the socket name, and format the name. */
-       auth_sock_name = xmalloc(MAXPATHLEN);
-       auth_sock_dir = xmalloc(MAXPATHLEN);
-       strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
+       auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
 
        /* Create private directory for socket */
        if (mkdtemp(auth_sock_dir) == NULL) {
                packet_send_debug("Agent forwarding disabled: "
                    "mkdtemp() failed: %.100s", strerror(errno));
                restore_uid();
-               xfree(auth_sock_name);
                xfree(auth_sock_dir);
-               auth_sock_name = NULL;
                auth_sock_dir = NULL;
-               return 0;
+               goto authsock_err;
        }
-       snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
-                auth_sock_dir, (long) getpid());
 
-       /* delete agent socket on fatal() */
-       fatal_add_cleanup(auth_sock_cleanup_proc, pw);
+       xasprintf(&auth_sock_name, "%s/agent.%ld",
+           auth_sock_dir, (long) getpid());
 
        /* Create the socket. */
        sock = socket(AF_UNIX, SOCK_STREAM, 0);
-       if (sock < 0)
-               packet_disconnect("socket: %.100s", strerror(errno));
+       if (sock < 0) {
+               error("socket: %.100s", strerror(errno));
+               restore_uid();
+               goto authsock_err;
+       }
 
        /* Bind it to the name. */
        memset(&sunaddr, 0, sizeof(sunaddr));
        sunaddr.sun_family = AF_UNIX;
        strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
 
-       if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
-               packet_disconnect("bind: %.100s", strerror(errno));
+       if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
+               error("bind: %.100s", strerror(errno));
+               restore_uid();
+               goto authsock_err;
+       }
 
        /* Restore the privileged uid. */
        restore_uid();
 
        /* Start listening on the socket. */
-       if (listen(sock, 5) < 0)
-               packet_disconnect("listen: %.100s", strerror(errno));
+       if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
+               error("listen: %.100s", strerror(errno));
+               goto authsock_err;
+       }
 
        /* Allocate a channel for the authentication agent socket. */
+       /* this shouldn't matter if its hpn or not - cjr */
        nc = channel_new("auth socket",
            SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
            CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
-           0, xstrdup("auth socket"), 1);
-       strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
+           0, "auth socket", 1);
+       nc->path = xstrdup(auth_sock_name);
        return 1;
+
+ authsock_err:
+       if (auth_sock_name != NULL)
+               xfree(auth_sock_name);
+       if (auth_sock_dir != NULL) {
+               rmdir(auth_sock_dir);
+               xfree(auth_sock_dir);
+       }
+       if (sock != -1)
+               close(sock);
+       auth_sock_name = NULL;
+       auth_sock_dir = NULL;
+       return 0;
 }
 
+static void
+display_loginmsg(void)
+{
+       if (buffer_len(&loginmsg) > 0) {
+               buffer_append(&loginmsg, "\0", 1);
+               printf("%s", (char *)buffer_ptr(&loginmsg));
+               buffer_clear(&loginmsg);
+       }
+}
 
 void
 do_authenticated(Authctxt *authctxt)
 {
-       /*
-        * Cancel the alarm we set to limit the time taken for
-        * authentication.
-        */
-       alarm(0);
-       if (startup_pipe != -1) {
-               close(startup_pipe);
-               startup_pipe = -1;
-       }
+       setproctitle("%s", authctxt->pw->pw_name);
 
        /* setup the channel layer */
        if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
@@ -224,17 +281,22 @@ do_authenticated(Authctxt *authctxt)
        else
                do_authenticated1(authctxt);
 
-       /* remove agent socket */
-       if (auth_sock_name != NULL)
-               auth_sock_cleanup_proc(authctxt->pw);
-#ifdef KRB4
-       if (options.kerberos_ticket_cleanup)
-               krb4_cleanup_proc(authctxt);
-#endif
-#ifdef KRB5
-       if (options.kerberos_ticket_cleanup)
-               krb5_cleanup_proc(authctxt);
+#ifdef SESSION_HOOKS
+        if (options.session_hooks_allow &&
+            options.session_hooks_shutdown_cmd)
+        {
+            execute_session_hook(options.session_hooks_shutdown_cmd,
+                                 authctxt,
+                                 /* startup = */ 0, /* save = */ 0);
+
+            if (authctxt->session_env_file)
+            {
+                free(authctxt->session_env_file);
+            }
+        }
 #endif
+
+       do_cleanup(authctxt);
 }
 
 /*
@@ -253,6 +315,10 @@ do_authenticated1(Authctxt *authctxt)
        u_int proto_len, data_len, dlen, compression_level = 0;
 
        s = session_new();
+       if (s == NULL) {
+               error("no more sessions");
+               return;
+       }
        s->authctxt = authctxt;
        s->pw = authctxt->pw;
 
@@ -272,11 +338,11 @@ do_authenticated1(Authctxt *authctxt)
                        compression_level = packet_get_int();
                        packet_check_eom();
                        if (compression_level < 1 || compression_level > 9) {
-                               packet_send_debug("Received illegal compression level %d.",
+                               packet_send_debug("Received invalid compression level %d.",
                                    compression_level);
                                break;
                        }
-                       if (!options.compression) {
+                       if (options.compression == COMP_NONE) {
                                debug2("compression disabled");
                                break;
                        }
@@ -316,7 +382,8 @@ do_authenticated1(Authctxt *authctxt)
                        break;
 
                case SSH_CMSG_AGENT_REQUEST_FORWARDING:
-                       if (no_agent_forwarding_flag || compat13) {
+                       if (!options.allow_agent_forwarding ||
+                           no_agent_forwarding_flag || compat13) {
                                debug("Authentication agent forwarding not permitted for this authentication.");
                                break;
                        }
@@ -334,7 +401,11 @@ do_authenticated1(Authctxt *authctxt)
                                break;
                        }
                        debug("Received TCP/IP port forwarding request.");
-                       channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
+                       if (channel_input_port_forward_request(s->pw->pw_uid == 0,
+                             options.gateway_ports) < 0) {
+                               debug("Port forwarding failed.");
+                               break;
+                       }
                        success = 1;
                        break;
 
@@ -343,67 +414,19 @@ do_authenticated1(Authctxt *authctxt)
                                success = 1;
                        break;
 
-#if defined(AFS) || defined(KRB5)
-               case SSH_CMSG_HAVE_KERBEROS_TGT:
-                       if (!options.kerberos_tgt_passing) {
-                               verbose("Kerberos TGT passing disabled.");
-                       } else {
-                               char *kdata = packet_get_string(&dlen);
-                               packet_check_eom();
-
-                               /* XXX - 0x41, see creds_to_radix version */
-                               if (kdata[0] != 0x41) {
-#ifdef KRB5
-                                       krb5_data tgt;
-                                       tgt.data = kdata;
-                                       tgt.length = dlen;
-
-                                       if (auth_krb5_tgt(s->authctxt, &tgt))
-                                               success = 1;
-                                       else
-                                               verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
-#endif /* KRB5 */
-                               } else {
-#ifdef AFS
-                                       if (auth_krb4_tgt(s->authctxt, kdata))
-                                               success = 1;
-                                       else
-                                               verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
-#endif /* AFS */
-                               }
-                               xfree(kdata);
-                       }
-                       break;
-#endif /* AFS || KRB5 */
-
-#ifdef AFS
-               case SSH_CMSG_HAVE_AFS_TOKEN:
-                       if (!options.afs_token_passing || !k_hasafs()) {
-                               verbose("AFS token passing disabled.");
-                       } else {
-                               /* Accept AFS token. */
-                               char *token = packet_get_string(&dlen);
-                               packet_check_eom();
-
-                               if (auth_afs_token(s->authctxt, token))
-                                       success = 1;
-                               else
-                                       verbose("AFS token refused for %.100s",
-                                           s->authctxt->user);
-                               xfree(token);
-                       }
-                       break;
-#endif /* AFS */
-
                case SSH_CMSG_EXEC_SHELL:
                case SSH_CMSG_EXEC_CMD:
                        if (type == SSH_CMSG_EXEC_CMD) {
                                command = packet_get_string(&dlen);
                                debug("Exec command '%.500s'", command);
-                               do_exec(s, command);
+                               if (do_exec(s, command) != 0)
+                                       packet_disconnect(
+                                           "command execution failed");
                                xfree(command);
                        } else {
-                               do_exec(s, NULL);
+                               if (do_exec(s, NULL) != 0)
+                                       packet_disconnect(
+                                           "shell execution failed");
                        }
                        packet_check_eom();
                        session_close(s);
@@ -414,7 +437,7 @@ do_authenticated1(Authctxt *authctxt)
                         * Any unknown messages in this phase are ignored,
                         * and a failure message is returned.
                         */
-                       log("Unknown packet type received after authentication: %d", type);
+                       logit("Unknown packet type received after authentication: %d", type);
                }
                packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
                packet_send();
@@ -428,55 +451,84 @@ do_authenticated1(Authctxt *authctxt)
        }
 }
 
+#define USE_PIPES
 /*
  * This is called to fork and execute a command when we have no tty.  This
  * will call do_child from the child, and server_loop from the parent after
  * setting up file descriptors and such.
  */
-void
+int
 do_exec_no_pty(Session *s, const char *command)
 {
        pid_t pid;
 
 #ifdef USE_PIPES
        int pin[2], pout[2], perr[2];
+
        /* Allocate pipes for communicating with the program. */
-       if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
-               packet_disconnect("Could not create pipes: %.100s",
-                                 strerror(errno));
-#else /* USE_PIPES */
+       if (pipe(pin) < 0) {
+               error("%s: pipe in: %.100s", __func__, strerror(errno));
+               return -1;
+       }
+       if (pipe(pout) < 0) {
+               error("%s: pipe out: %.100s", __func__, strerror(errno));
+               close(pin[0]);
+               close(pin[1]);
+               return -1;
+       }
+       if (pipe(perr) < 0) {
+               error("%s: pipe err: %.100s", __func__, strerror(errno));
+               close(pin[0]);
+               close(pin[1]);
+               close(pout[0]);
+               close(pout[1]);
+               return -1;
+       }
+#else
        int inout[2], err[2];
+
        /* Uses socket pairs to communicate with the program. */
-       if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
-           socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
-               packet_disconnect("Could not create socket pairs: %.100s",
-                                 strerror(errno));
-#endif /* USE_PIPES */
+       if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
+               error("%s: socketpair #1: %.100s", __func__, strerror(errno));
+               return -1;
+       }
+       if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
+               error("%s: socketpair #2: %.100s", __func__, strerror(errno));
+               close(inout[0]);
+               close(inout[1]);
+               return -1;
+       }
+#endif
+
        if (s == NULL)
                fatal("do_exec_no_pty: no session");
 
        session_proctitle(s);
 
-#if defined(GSSAPI)
-       temporarily_use_uid(s->pw);
-       ssh_gssapi_storecreds();
-       restore_uid();
-#endif
-
-#if defined(USE_PAM)
-       do_pam_session(s->pw->pw_name, NULL);
-       do_pam_setcred(1);
-       if (is_pam_password_change_required())
-               packet_disconnect("Password change required but no "
-                   "TTY available");
-#endif /* USE_PAM */
-
        /* Fork the child. */
-       if ((pid = fork()) == 0) {
-               fatal_remove_all_cleanups();
+       switch ((pid = fork())) {
+       case -1:
+               error("%s: fork: %.100s", __func__, strerror(errno));
+#ifdef USE_PIPES
+               close(pin[0]);
+               close(pin[1]);
+               close(pout[0]);
+               close(pout[1]);
+               close(perr[0]);
+               close(perr[1]);
+#else
+               close(inout[0]);
+               close(inout[1]);
+               close(err[0]);
+               close(err[1]);
+#endif
+               return -1;
+       case 0:
+               is_child = 1;
 
                /* Child.  Reinitialize the log since the pid has changed. */
-               log_init(__progname, options.log_level, options.log_facility, log_stderr);
+               log_init(__progname, options.log_level,
+                   options.log_facility, log_stderr);
 
                /*
                 * Create a new session and process group since the 4.4BSD
@@ -506,7 +558,7 @@ do_exec_no_pty(Session *s, const char *command)
                if (dup2(perr[1], 2) < 0)
                        perror("dup2 stderr");
                close(perr[1]);
-#else /* USE_PIPES */
+#else
                /*
                 * Redirect stdin, stdout, and stderr.  Stdin and stdout will
                 * use the same socket, as some programs (particularly rdist)
@@ -516,11 +568,14 @@ do_exec_no_pty(Session *s, const char *command)
                close(err[1]);
                if (dup2(inout[0], 0) < 0)      /* stdin */
                        perror("dup2 stdin");
-               if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
+               if (dup2(inout[0], 1) < 0)      /* stdout (same as stdin) */
                        perror("dup2 stdout");
+               close(inout[0]);
                if (dup2(err[0], 2) < 0)        /* stderr */
                        perror("dup2 stderr");
-#endif /* USE_PIPES */
+               close(err[0]);
+#endif
+
 
 #ifdef _UNICOS
                cray_init_job(s->pw); /* set up cray jid and tmpdir */
@@ -529,19 +584,28 @@ do_exec_no_pty(Session *s, const char *command)
                /* Do processing for the child (exec command etc). */
                do_child(s, command);
                /* NOTREACHED */
+       default:
+               break;
        }
+
 #ifdef _UNICOS
        signal(WJSIGNAL, cray_job_termination_handler);
 #endif /* _UNICOS */
 #ifdef HAVE_CYGWIN
-       if (is_winnt)
-               cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
+       cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 #endif
-       if (pid < 0)
-               packet_disconnect("fork failed: %.100s", strerror(errno));
+
        s->pid = pid;
        /* Set interactive/non-interactive mode. */
        packet_set_interactive(s->display != NULL);
+
+       /*
+        * Clear loginmsg, since it's the child's responsibility to display
+        * it to the user, otherwise multiple sessions may accumulate
+        * multiple copies of the login messages.
+        */
+       buffer_clear(&loginmsg);
+
 #ifdef USE_PIPES
        /* We are the parent.  Close the child sides of the pipes. */
        close(pin[0]);
@@ -549,13 +613,17 @@ do_exec_no_pty(Session *s, const char *command)
        close(perr[1]);
 
        if (compat20) {
-               session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
+               if (s->is_subsystem) {
+                       close(perr[0]);
+                       perr[0] = -1;
+               }
+               session_set_fds(s, pin[1], pout[0], perr[0], 0);
        } else {
                /* Enter the interactive session. */
                server_loop(pid, pin[1], pout[0], perr[0]);
                /* server_loop has closed pin[1], pout[0], and perr[0]. */
        }
-#else /* USE_PIPES */
+#else
        /* We are the parent.  Close the child sides of the socket pairs. */
        close(inout[0]);
        close(err[0]);
@@ -565,12 +633,16 @@ do_exec_no_pty(Session *s, const char *command)
         * handle the case that fdin and fdout are the same.
         */
        if (compat20) {
-               session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
+               session_set_fds(s, inout[1], inout[1],
+                   s->is_subsystem ? -1 : err[1], 0);
+               if (s->is_subsystem)
+                       close(err[1]);
        } else {
                server_loop(pid, inout[1], inout[1], err[1]);
                /* server_loop has closed inout[1] and err[1]. */
        }
-#endif /* USE_PIPES */
+#endif
+       return 0;
 }
 
 /*
@@ -579,7 +651,7 @@ do_exec_no_pty(Session *s, const char *command)
  * setting up file descriptors, controlling tty, updating wtmp, utmp,
  * lastlog, and other such operations.
  */
-void
+int
 do_exec_pty(Session *s, const char *command)
 {
        int fdout, ptyfd, ttyfd, ptymaster;
@@ -590,23 +662,46 @@ do_exec_pty(Session *s, const char *command)
        ptyfd = s->ptyfd;
        ttyfd = s->ttyfd;
 
-#if defined(GSSAPI)
-       temporarily_use_uid(s->pw);
-       ssh_gssapi_storecreds();
-       restore_uid();
-#endif
-
-#if defined(USE_PAM)
-       do_pam_session(s->pw->pw_name, s->tty);
-       do_pam_setcred(1);
-#endif
+       /*
+        * Create another descriptor of the pty master side for use as the
+        * standard input.  We could use the original descriptor, but this
+        * simplifies code in server_loop.  The descriptor is bidirectional.
+        * Do this before forking (and cleanup in the child) so as to
+        * detect and gracefully fail out-of-fd conditions.
+        */
+       if ((fdout = dup(ptyfd)) < 0) {
+               error("%s: dup #1: %s", __func__, strerror(errno));
+               close(ttyfd);
+               close(ptyfd);
+               return -1;
+       }
+       /* we keep a reference to the pty master */
+       if ((ptymaster = dup(ptyfd)) < 0) {
+               error("%s: dup #2: %s", __func__, strerror(errno));
+               close(ttyfd);
+               close(ptyfd);
+               close(fdout);
+               return -1;
+       }
 
        /* Fork the child. */
-       if ((pid = fork()) == 0) {
-               fatal_remove_all_cleanups();
+       switch ((pid = fork())) {
+       case -1:
+               error("%s: fork: %.100s", __func__, strerror(errno));
+               close(fdout);
+               close(ptymaster);
+               close(ttyfd);
+               close(ptyfd);
+               return -1;
+       case 0:
+               is_child = 1;
+
+               close(fdout);
+               close(ptymaster);
 
                /* Child.  Reinitialize the log because the pid has changed. */
-               log_init(__progname, options.log_level, options.log_facility, log_stderr);
+               log_init(__progname, options.log_level,
+                   options.log_facility, log_stderr);
                /* Close the master side of the pseudo tty. */
                close(ptyfd);
 
@@ -637,48 +732,38 @@ do_exec_pty(Session *s, const char *command)
                        do_pre_login(s);
 # endif
 #endif
-
-               /* Do common processing for the child, such as execing the command. */
+               /*
+                * Do common processing for the child, such as execing
+                * the command.
+                */
                do_child(s, command);
                /* NOTREACHED */
+       default:
+               break;
        }
+
 #ifdef _UNICOS
        signal(WJSIGNAL, cray_job_termination_handler);
 #endif /* _UNICOS */
 #ifdef HAVE_CYGWIN
-       if (is_winnt)
-               cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
+       cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 #endif
-       if (pid < 0)
-               packet_disconnect("fork failed: %.100s", strerror(errno));
+
        s->pid = pid;
 
        /* Parent.  Close the slave side of the pseudo tty. */
        close(ttyfd);
 
-       /*
-        * Create another descriptor of the pty master side for use as the
-        * standard input.  We could use the original descriptor, but this
-        * simplifies code in server_loop.  The descriptor is bidirectional.
-        */
-       fdout = dup(ptyfd);
-       if (fdout < 0)
-               packet_disconnect("dup #1 failed: %.100s", strerror(errno));
-
-       /* we keep a reference to the pty master */
-       ptymaster = dup(ptyfd);
-       if (ptymaster < 0)
-               packet_disconnect("dup #2 failed: %.100s", strerror(errno));
-       s->ptymaster = ptymaster;
-
        /* Enter interactive session. */
+       s->ptymaster = ptymaster;
        packet_set_interactive(1);
        if (compat20) {
-               session_set_fds(s, ptyfd, fdout, -1);
+               session_set_fds(s, ptyfd, fdout, -1, 1);
        } else {
                server_loop(pid, ptyfd, fdout, -1);
                /* server_loop _has_ closed ptyfd and fdout. */
        }
+       return 0;
 }
 
 #ifdef LOGIN_NEEDS_UTMPX
@@ -697,15 +782,15 @@ do_pre_login(Session *s)
        fromlen = sizeof(from);
        if (packet_connection_is_on_socket()) {
                if (getpeername(packet_get_connection_in(),
-                   (struct sockaddr *) & from, &fromlen) < 0) {
+                   (struct sockaddr *)&from, &fromlen) < 0) {
                        debug("getpeername: %.100s", strerror(errno));
-                       fatal_cleanup();
+                       cleanup_exit(255);
                }
        }
 
        record_utmp_only(pid, s->tty, s->pw->pw_name,
-           get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
-           (struct sockaddr *)&from);
+           get_remote_name_or_ip(utmp_len, options.use_dns),
+           (struct sockaddr *)&from, fromlen);
 }
 #endif
 
@@ -713,29 +798,81 @@ do_pre_login(Session *s)
  * This is called to fork and execute a command.  If another command is
  * to be forced, execute that instead.
  */
-void
+int
 do_exec(Session *s, const char *command)
 {
-       if (forced_command) {
+       int ret;
+
+       if (options.adm_forced_command) {
+               original_command = command;
+               command = options.adm_forced_command;
+               if (IS_INTERNAL_SFTP(command))
+                       s->is_subsystem = SUBSYSTEM_INT_SFTP;
+               else if (s->is_subsystem)
+                       s->is_subsystem = SUBSYSTEM_EXT;
+               debug("Forced command (config) '%.900s'", command);
+       } else if (forced_command) {
                original_command = command;
                command = forced_command;
-               debug("Forced command '%.900s'", command);
+               if (IS_INTERNAL_SFTP(command))
+                       s->is_subsystem = SUBSYSTEM_INT_SFTP;
+               else if (s->is_subsystem)
+                       s->is_subsystem = SUBSYSTEM_EXT;
+               debug("Forced command (key option) '%.900s'", command);
+       }
+
+#if defined(SESSION_HOOKS)
+       if (options.session_hooks_allow &&
+           (options.session_hooks_startup_cmd ||
+            options.session_hooks_shutdown_cmd))
+       {
+               char env_file[1000];
+               struct stat st;
+               do
+               {
+                       snprintf(env_file,
+                                sizeof(env_file),
+                                "/tmp/ssh_env_%d%d%d",
+                                getuid(),
+                                getpid(),
+                                rand());
+               } while (stat(env_file, &st)==0);
+               s->authctxt->session_env_file = strdup(env_file);
        }
+#endif
+
+#ifdef SSH_AUDIT_EVENTS
+       if (command != NULL)
+               PRIVSEP(audit_run_command(command));
+       else if (s->ttyfd == -1) {
+               char *shell = s->pw->pw_shell;
 
+               if (shell[0] == '\0')   /* empty shell means /bin/sh */
+                       shell =_PATH_BSHELL;
+               PRIVSEP(audit_run_command(shell));
+       }
+#endif
        if (s->ttyfd != -1)
-               do_exec_pty(s, command);
+               ret = do_exec_pty(s, command);
        else
-               do_exec_no_pty(s, command);
+               ret = do_exec_no_pty(s, command);
 
        original_command = NULL;
-}
 
+       /*
+        * Clear loginmsg: it's the child's responsibility to display
+        * it to the user, otherwise multiple sessions may accumulate
+        * multiple copies of the login messages.
+        */
+       buffer_clear(&loginmsg);
+
+       return ret;
+}
 
 /* administrative, login(1)-like work */
 void
 do_login(Session *s, const char *command)
 {
-       char *time_string;
        socklen_t fromlen;
        struct sockaddr_storage from;
        struct passwd * pw = s->pw;
@@ -746,12 +883,12 @@ do_login(Session *s, const char *command)
         * the address be 0.0.0.0.
         */
        memset(&from, 0, sizeof(from));
+       fromlen = sizeof(from);
        if (packet_connection_is_on_socket()) {
-               fromlen = sizeof(from);
                if (getpeername(packet_get_connection_in(),
-                   (struct sockaddr *) & from, &fromlen) < 0) {
+                   (struct sockaddr *)&from, &fromlen) < 0) {
                        debug("getpeername: %.100s", strerror(errno));
-                       fatal_cleanup();
+                       cleanup_exit(255);
                }
        }
 
@@ -759,7 +896,7 @@ do_login(Session *s, const char *command)
        if (!use_privsep)
                record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
                    get_remote_name_or_ip(utmp_len,
-                   options.verify_reverse_mapping),
+                   options.use_dns),
                    (struct sockaddr *)&from, fromlen);
 
 #ifdef USE_PAM
@@ -767,36 +904,18 @@ do_login(Session *s, const char *command)
         * If password change is needed, do it now.
         * This needs to occur before the ~/.hushlogin check.
         */
-       if (is_pam_password_change_required()) {
-               print_pam_messages();
+       if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
+               display_loginmsg();
                do_pam_chauthtok();
+               s->authctxt->force_pwchange = 0;
+               /* XXX - signal [net] parent to enable forwardings */
        }
 #endif
 
        if (check_quietlogin(s, command))
                return;
 
-#ifdef USE_PAM
-       if (!is_pam_password_change_required())
-               print_pam_messages();
-#endif /* USE_PAM */
-#ifdef WITH_AIXAUTHENTICATE
-       if (aixloginmsg && *aixloginmsg)
-               printf("%s\n", aixloginmsg);
-#endif /* WITH_AIXAUTHENTICATE */
-
-#ifndef NO_SSH_LASTLOG
-       if (options.print_lastlog && s->last_login_time != 0) {
-               time_string = ctime(&s->last_login_time);
-               if (strchr(time_string, '\n'))
-                       *strchr(time_string, '\n') = 0;
-               if (strcmp(s->hostname, "") == 0)
-                       printf("Last login: %s\r\n", time_string);
-               else
-                       printf("Last login: %s from %s\r\n", time_string,
-                           s->hostname);
-       }
-#endif /* NO_SSH_LASTLOG */
+       display_loginmsg();
 
        do_motd();
 }
@@ -852,14 +971,25 @@ check_quietlogin(Session *s, const char *command)
 
 /*
  * Sets the value of the given variable in the environment.  If the variable
- * already exists, its value is overriden.
+ * already exists, its value is overridden.
  */
 void
 child_set_env(char ***envp, u_int *envsizep, const char *name,
        const char *value)
 {
-       u_int i, namelen;
        char **env;
+       u_int envsize;
+       u_int i, namelen;
+
+       /*
+        * If we're passed an uninitialized list, allocate a single null
+        * entry before continuing.
+        */
+       if (*envp == NULL && *envsizep == 0) {
+               *envp = xmalloc(sizeof(char *));
+               *envp[0] = NULL;
+               *envsizep = 1;
+       }
 
        /*
         * Find the slot where the value should be stored.  If the variable
@@ -876,12 +1006,13 @@ child_set_env(char ***envp, u_int *envsizep, const char *name,
                xfree(env[i]);
        } else {
                /* New variable.  Expand if necessary. */
-               if (i >= (*envsizep) - 1) {
-                       if (*envsizep >= 1000)
-                               fatal("child_set_env: too many env vars,"
-                                   " skipping: %.100s", name);
-                       (*envsizep) += 50;
-                       env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
+               envsize = *envsizep;
+               if (i >= envsize - 1) {
+                       if (envsize >= 1000)
+                               fatal("child_set_env: too many env vars");
+                       envsize += 50;
+                       env = (*envp) = xrealloc(env, envsize, sizeof(char *));
+                       *envsizep = envsize;
                }
                /* Need to set the NULL pointer at end of array beyond the new slot. */
                env[i + 1] = NULL;
@@ -918,8 +1049,9 @@ read_environment_file(char ***env, u_int *envsize,
                        ;
                if (!*cp || *cp == '#' || *cp == '\n')
                        continue;
-               if (strchr(cp, '\n'))
-                       *strchr(cp, '\n') = '\0';
+
+               cp[strcspn(cp, "\n")] = '\0';
+
                value = strchr(cp, '=');
                if (value == NULL) {
                        fprintf(stderr, "Bad line %u in %.100s\n", lineno,
@@ -937,7 +1069,174 @@ read_environment_file(char ***env, u_int *envsize,
        fclose(f);
 }
 
-void copy_environment(char **source, char ***env, u_int *envsize)
+#ifdef SESSION_HOOKS
+#define SSH_SESSION_ENV_FILE "SSH_SESSION_ENV_FILE"
+
+typedef enum { no_op, execute, clear_env, restore_env,
+               read_env, save_or_rm_env } session_action_t;
+
+static session_action_t action_order[2][5] = {
+    { clear_env, read_env, execute, save_or_rm_env, restore_env }, /*shutdown*/
+    { execute, read_env, save_or_rm_env, no_op, no_op }            /*startup */
+};
+
+static
+void execute_session_hook(char* prog, Authctxt *authctxt,
+                          int startup, int save)
+{
+    extern char **environ;
+
+    struct stat  st;
+    char         **saved_env, **tmpenv;
+    char         *env_file = authctxt->session_env_file;
+    int          i, status = 0;
+
+    for (i=0; i<5; i++)
+    {
+        switch (action_order[startup][i])
+        {
+          case no_op:
+            break;
+
+          case execute:
+            {
+                FILE* fp;
+                char  buf[1000];
+
+                snprintf(buf,
+                         sizeof(buf),
+                         "%s -c '%s'",
+                         authctxt->pw->pw_shell,
+                         prog);
+
+                debug("executing session hook: [%s]", buf);
+                setenv(SSH_SESSION_ENV_FILE, env_file, /* overwrite = */ 1);
+
+                /* flusing is recommended in the popen(3) man page, to avoid
+                   intermingling of output */
+                fflush(stdout);
+                fflush(stderr);
+                if ((fp=popen(buf, "w")) == NULL)
+                {
+                    perror("Unable to run session hook");
+                    return;
+                }
+                status = pclose(fp);
+                debug2("session hook executed, status=%d", status);
+                unsetenv(SSH_SESSION_ENV_FILE);
+            }
+            break;
+
+          case clear_env:
+            saved_env = environ;
+            tmpenv = (char**) malloc(sizeof(char*));
+            tmpenv[0] = NULL;
+            environ = tmpenv;
+            break;
+
+          case restore_env:
+            environ = saved_env;
+            free(tmpenv);
+            break;
+
+          case read_env:
+            if (status==0 && stat(env_file, &st)==0)
+            {
+                int envsize = 0;
+
+                debug("reading environment from %s", env_file);
+                while (environ[envsize++]) ;
+                read_environment_file(&environ, &envsize, env_file);
+            }
+            break;
+
+          case save_or_rm_env:
+            if (status==0 && save)
+            {
+                FILE* fp;
+                int    envcount=0;
+
+                debug2("saving environment to %s", env_file);
+                if ((fp = fopen(env_file, "w")) == NULL) /* hmm: file perms? */
+                {
+                    perror("Unable to save session hook info");
+                }
+                while (environ[envcount])
+                {
+                    fprintf(fp, "%s\n", environ[envcount++]);
+                }
+                fflush(fp);
+                fclose(fp);
+            }
+            else if (stat(env_file, &st)==0)
+            {
+                debug2("removing environment file %s", env_file);
+                remove(env_file);
+            }
+            break;
+        }
+    }
+
+}
+#endif
+
+#ifdef HAVE_ETC_DEFAULT_LOGIN
+/*
+ * Return named variable from specified environment, or NULL if not present.
+ */
+static char *
+child_get_env(char **env, const char *name)
+{
+       int i;
+       size_t len;
+
+       len = strlen(name);
+       for (i=0; env[i] != NULL; i++)
+               if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
+                       return(env[i] + len + 1);
+       return NULL;
+}
+
+/*
+ * Read /etc/default/login.
+ * We pick up the PATH (or SUPATH for root) and UMASK.
+ */
+static void
+read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
+{
+       char **tmpenv = NULL, *var;
+       u_int i, tmpenvsize = 0;
+       u_long mask;
+
+       /*
+        * We don't want to copy the whole file to the child's environment,
+        * so we use a temporary environment and copy the variables we're
+        * interested in.
+        */
+       read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
+
+       if (tmpenv == NULL)
+               return;
+
+       if (uid == 0)
+               var = child_get_env(tmpenv, "SUPATH");
+       else
+               var = child_get_env(tmpenv, "PATH");
+       if (var != NULL)
+               child_set_env(env, envsize, "PATH", var);
+
+       if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
+               if (sscanf(var, "%5lo", &mask) == 1)
+                       umask((mode_t)mask);
+
+       for (i = 0; tmpenv[i] != NULL; i++)
+               xfree(tmpenv[i]);
+       xfree(tmpenv);
+}
+#endif /* HAVE_ETC_DEFAULT_LOGIN */
+
+void
+copy_environment(char **source, char ***env, u_int *envsize)
 {
        char *var_name, *var_val;
        int i;
@@ -955,7 +1254,7 @@ void copy_environment(char **source, char ***env, u_int *envsize)
 
                debug3("Copy environment: %s=%s", var_name, var_val);
                child_set_env(env, envsize, var_name, var_val);
-               
+
                xfree(var_name);
        }
 }
@@ -965,12 +1264,15 @@ do_setup_env(Session *s, const char *shell)
 {
        char buf[256];
        u_int i, envsize;
-       char **env;
+       char **env, *laddr;
        struct passwd *pw = s->pw;
+#if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
+       char *path = NULL;
+#endif
 
        /* Initialize the environment. */
        envsize = 100;
-       env = xmalloc(envsize * sizeof(char *));
+       env = xcalloc(envsize, sizeof(char *));
        env[0] = NULL;
 
 #ifdef HAVE_CYGWIN
@@ -978,20 +1280,33 @@ do_setup_env(Session *s, const char *shell)
         * The Windows environment contains some setting which are
         * important for a running system. They must not be dropped.
         */
-       copy_environment(environ, &env, &envsize);
+       {
+               char **p;
+
+               p = fetch_windows_environment();
+               copy_environment(p, &env, &envsize);
+               free_windows_environment(p);
+       }
 #endif
 
 #ifdef GSSAPI
-       /* Allow any GSSAPI methods that we've used to alter 
+       /* Allow any GSSAPI methods that we've used to alter
         * the childs environment as they see fit
         */
-       ssh_gssapi_do_child(&env,&envsize);
+       ssh_gssapi_do_child(&env, &envsize);
 #endif
 
        if (!options.use_login) {
                /* Set basic environment. */
+               for (i = 0; i < s->num_env; i++)
+                       child_set_env(&env, &envsize, s->env[i].name,
+                           s->env[i].val);
+
                child_set_env(&env, &envsize, "USER", pw->pw_name);
                child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
+#ifdef _AIX
+               child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
+#endif
                child_set_env(&env, &envsize, "HOME", pw->pw_dir);
 #ifdef HAVE_LOGIN_CAP
                if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
@@ -1006,12 +1321,15 @@ do_setup_env(Session *s, const char *shell)
                 * needed for loading shared libraries. So the path better
                 * remains intact here.
                 */
-#  ifdef SUPERUSER_PATH
-               child_set_env(&env, &envsize, "PATH", 
-                   s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH);
-#  else 
-               child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
-#  endif /* SUPERUSER_PATH */
+#  ifdef HAVE_ETC_DEFAULT_LOGIN
+               read_etc_default_login(&env, &envsize, pw->pw_uid);
+               path = child_get_env(env, "PATH");
+#  endif /* HAVE_ETC_DEFAULT_LOGIN */
+               if (path == NULL || *path == '\0') {
+                       child_set_env(&env, &envsize, "PATH",
+                           s->pw->pw_uid == 0 ?
+                               SUPERUSER_PATH : _PATH_STDPATH);
+               }
 # endif /* HAVE_CYGWIN */
 #endif /* HAVE_LOGIN_CAP */
 
@@ -1025,6 +1343,23 @@ do_setup_env(Session *s, const char *shell)
        if (getenv("TZ"))
                child_set_env(&env, &envsize, "TZ", getenv("TZ"));
 
+#ifdef GSI /* GSI shared libs typically installed in non-system locations. */
+       {
+               char *cp;
+
+               if ((cp = getenv("LD_LIBRARY_PATH")) != NULL)
+                       child_set_env(&env, &envsize, "LD_LIBRARY_PATH", cp);
+               if ((cp = getenv("LIBPATH")) != NULL)
+                       child_set_env(&env, &envsize, "LIBPATH", cp);
+               if ((cp = getenv("SHLIB_PATH")) != NULL)
+                       child_set_env(&env, &envsize, "SHLIB_PATH", cp);
+               if ((cp = getenv("LD_LIBRARYN32_PATH")) != NULL)
+                       child_set_env(&env, &envsize, "LD_LIBRARYN32_PATH",cp);
+               if ((cp = getenv("LD_LIBRARY64_PATH")) != NULL)
+                       child_set_env(&env, &envsize, "LD_LIBRARY64_PATH",cp);
+       }
+#endif
+
        /* Set custom environment options from RSA authentication. */
        if (!options.use_login) {
                while (custom_environment) {
@@ -1048,9 +1383,10 @@ do_setup_env(Session *s, const char *shell)
            get_remote_ipaddr(), get_remote_port(), get_local_port());
        child_set_env(&env, &envsize, "SSH_CLIENT", buf);
 
+       laddr = get_local_ipaddr(packet_get_connection_in());
        snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
-           get_remote_ipaddr(), get_remote_port(),
-           get_local_ipaddr(packet_get_connection_in()), get_local_port());
+           get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
+       xfree(laddr);
        child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
 
        if (s->ttyfd != -1)
@@ -1068,35 +1404,44 @@ do_setup_env(Session *s, const char *shell)
                child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
 #endif /* _UNICOS */
 
+       /*
+        * Since we clear KRB5CCNAME at startup, if it's set now then it
+        * must have been set by a native authentication method (eg AIX or
+        * SIA), so copy it to the child.
+        */
+       {
+               char *cp;
+
+               if ((cp = getenv("KRB5CCNAME")) != NULL)
+                       child_set_env(&env, &envsize, "KRB5CCNAME", cp);
+       }
+
 #ifdef _AIX
        {
                char *cp;
 
                if ((cp = getenv("AUTHSTATE")) != NULL)
                        child_set_env(&env, &envsize, "AUTHSTATE", cp);
-               if ((cp = getenv("KRB5CCNAME")) != NULL)
-                       child_set_env(&env, &envsize, "KRB5CCNAME", cp);
                read_environment_file(&env, &envsize, "/etc/environment");
        }
 #endif
-#ifdef KRB4
-       if (s->authctxt->krb4_ticket_file)
-               child_set_env(&env, &envsize, "KRBTKFILE",
-                   s->authctxt->krb4_ticket_file);
-#endif
 #ifdef KRB5
-       if (s->authctxt->krb5_ticket_file)
+       if (s->authctxt->krb5_ccname)
                child_set_env(&env, &envsize, "KRB5CCNAME",
-                   s->authctxt->krb5_ticket_file);
+                   s->authctxt->krb5_ccname);
 #endif
 #ifdef USE_PAM
        /*
         * Pull in any environment variables that may have
         * been set by PAM.
         */
-       {
+       if (options.use_pam) {
                char **p;
 
+               p = fetch_pam_child_environment();
+               copy_environment(p, &env, &envsize);
+               free_pam_environment(p);
+
                p = fetch_pam_environment();
                copy_environment(p, &env, &envsize);
                free_pam_environment(p);
@@ -1137,8 +1482,9 @@ do_rc_files(Session *s, const char *shell)
        do_xauth =
            s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
 
-       /* ignore _PATH_SSH_USER_RC for subsystems */
-       if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
+       /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
+       if (!s->is_subsystem && options.adm_forced_command == NULL &&
+           !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
                snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
                    shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
                if (debug_flag)
@@ -1169,8 +1515,10 @@ do_rc_files(Session *s, const char *shell)
                /* Add authority data to .Xauthority if appropriate. */
                if (debug_flag) {
                        fprintf(stderr,
-                           "Running %.500s add "
-                           "%.100s %.100s %.100s\n",
+                           "Running %.500s remove %.100s\n",
+                           options.xauth_location, s->auth_display);
+                       fprintf(stderr,
+                           "%.500s add %.100s %.100s %.100s\n",
                            options.xauth_location, s->auth_display,
                            s->auth_proto, s->auth_data);
                }
@@ -1178,6 +1526,8 @@ do_rc_files(Session *s, const char *shell)
                    options.xauth_location);
                f = popen(cmd, "w");
                if (f) {
+                       fprintf(f, "remove %s\n",
+                           s->auth_display);
                        fprintf(f, "add %s %s %s\n",
                            s->auth_display, s->auth_proto,
                            s->auth_data);
@@ -1205,33 +1555,97 @@ do_nologin(struct passwd *pw)
 #endif
        if (f) {
                /* /etc/nologin exists.  Print its contents and exit. */
-               log("User %.100s not allowed because %s exists",
+               logit("User %.100s not allowed because %s exists",
                    pw->pw_name, _PATH_NOLOGIN);
                while (fgets(buf, sizeof(buf), f))
                        fputs(buf, stderr);
                fclose(f);
+               fflush(NULL);
                exit(254);
        }
 }
 
+/*
+ * Chroot into a directory after checking it for safety: all path components
+ * must be root-owned directories with strict permissions.
+ */
+static void
+safely_chroot(const char *path, uid_t uid)
+{
+       const char *cp;
+       char component[MAXPATHLEN];
+       struct stat st;
+
+       if (*path != '/')
+               fatal("chroot path does not begin at root");
+       if (strlen(path) >= sizeof(component))
+               fatal("chroot path too long");
+
+       /*
+        * Descend the path, checking that each component is a
+        * root-owned directory with strict permissions.
+        */
+       for (cp = path; cp != NULL;) {
+               if ((cp = strchr(cp, '/')) == NULL)
+                       strlcpy(component, path, sizeof(component));
+               else {
+                       cp++;
+                       memcpy(component, path, cp - path);
+                       component[cp - path] = '\0';
+               }
+       
+               debug3("%s: checking '%s'", __func__, component);
+
+               if (stat(component, &st) != 0)
+                       fatal("%s: stat(\"%s\"): %s", __func__,
+                           component, strerror(errno));
+               if (st.st_uid != 0 || (st.st_mode & 022) != 0)
+                       fatal("bad ownership or modes for chroot "
+                           "directory %s\"%s\"", 
+                           cp == NULL ? "" : "component ", component);
+               if (!S_ISDIR(st.st_mode))
+                       fatal("chroot path %s\"%s\" is not a directory",
+                           cp == NULL ? "" : "component ", component);
+
+       }
+
+       if (chdir(path) == -1)
+               fatal("Unable to chdir to chroot path \"%s\": "
+                   "%s", path, strerror(errno));
+       if (chroot(path) == -1)
+               fatal("chroot(\"%s\"): %s", path, strerror(errno));
+       if (chdir("/") == -1)
+               fatal("%s: chdir(/) after chroot: %s",
+                   __func__, strerror(errno));
+       verbose("Changed root directory to \"%s\"", path);
+}
+
 /* Set login name, uid, gid, and groups. */
 void
 do_setusercontext(struct passwd *pw)
 {
-#ifdef HAVE_CYGWIN
-       if (is_winnt) {
-#else /* HAVE_CYGWIN */
-       if (getuid() == 0 || geteuid() == 0) {
+       char *chroot_path, *tmp;
+
+#ifdef WITH_SELINUX
+       /* Cache selinux status for later use */
+       (void)ssh_selinux_enabled();
+#endif
+
+#ifndef HAVE_CYGWIN
+       if (getuid() == 0 || geteuid() == 0)
 #endif /* HAVE_CYGWIN */
-#ifdef HAVE_SETPCRED
-               setpcred(pw->pw_name);
-#endif /* HAVE_SETPCRED */
+       {
 #ifdef HAVE_LOGIN_CAP
 # ifdef __bsdi__
                setpgid(0, 0);
 # endif
+# ifdef USE_PAM
+               if (options.use_pam) {
+                       do_pam_setcred(use_privsep);
+               }
+# endif /* USE_PAM */
                if (setusercontext(lc, pw, pw->pw_uid,
-                   (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
+                   (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
                        perror("unable to set user context");
                        exit(1);
                }
@@ -1256,24 +1670,81 @@ do_setusercontext(struct passwd *pw)
                endgrent();
 # ifdef USE_PAM
                /*
-                * PAM credentials may take the form of supplementary groups. 
+                * PAM credentials may take the form of supplementary groups.
                 * These will have been wiped by the above initgroups() call.
                 * Reestablish them here.
                 */
-               do_pam_setcred(0);
+               if (options.use_pam) {
+                       do_pam_setcred(use_privsep);
+               }
 # endif /* USE_PAM */
 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
                irix_setusercontext(pw);
-#  endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
+# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
 # ifdef _AIX
                aix_usrinfo(pw);
 # endif /* _AIX */
+# ifdef USE_LIBIAF
+               if (set_id(pw->pw_name) != 0) {
+                       exit(1);
+               }
+# endif /* USE_LIBIAF */
+#endif
+
+               if (options.chroot_directory != NULL &&
+                   strcasecmp(options.chroot_directory, "none") != 0) {
+                        tmp = tilde_expand_filename(options.chroot_directory,
+                           pw->pw_uid);
+                       chroot_path = percent_expand(tmp, "h", pw->pw_dir,
+                           "u", pw->pw_name, (char *)NULL);
+                       safely_chroot(chroot_path, pw->pw_uid);
+                       free(tmp);
+                       free(chroot_path);
+               }
+
+#ifdef HAVE_SETPCRED
+               if (setpcred(pw->pw_name, (char **)NULL) == -1)
+                       fatal("Failed to set process credentials");
+#endif /* HAVE_SETPCRED */
+#ifdef HAVE_LOGIN_CAP
+               if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
+                       perror("unable to set user context (setuser)");
+                       exit(1);
+               }
+#else
                /* Permanently switch to the desired uid. */
                permanently_set_uid(pw);
 #endif
        }
+
        if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
                fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
+
+#ifdef WITH_SELINUX
+       ssh_selinux_setup_exec_context(pw->pw_name);
+#endif
+}
+
+static void
+do_pwchange(Session *s)
+{
+       fflush(NULL);
+       fprintf(stderr, "WARNING: Your password has expired.\n");
+       if (s->ttyfd != -1) {
+               fprintf(stderr,
+                   "You must change your password now and login again!\n");
+#ifdef PASSWD_NEEDS_USERNAME
+               execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
+                   (char *)NULL);
+#else
+               execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
+#endif
+               perror("passwd");
+       } else {
+               fprintf(stderr,
+                   "Password change required but no TTY available.\n");
+       }
+       exit(1);
 }
 
 static void
@@ -1297,20 +1768,55 @@ launch_login(struct passwd *pw, const char *hostname)
        exit(1);
 }
 
+static void
+child_close_fds(void)
+{
+       int i;
+
+       if (packet_get_connection_in() == packet_get_connection_out())
+               close(packet_get_connection_in());
+       else {
+               close(packet_get_connection_in());
+               close(packet_get_connection_out());
+       }
+       /*
+        * Close all descriptors related to channels.  They will still remain
+        * open in the parent.
+        */
+       /* XXX better use close-on-exec? -markus */
+       channel_close_all();
+
+       /*
+        * Close any extra file descriptors.  Note that there may still be
+        * descriptors left by system functions.  They will be closed later.
+        */
+       endpwent();
+
+       /*
+        * Close any extra open file descriptors so that we don't have them
+        * hanging around in clients.  Note that we want to do this after
+        * initgroups, because at least on Solaris 2.3 it leaves file
+        * descriptors open.
+        */
+       for (i = 3; i < 64; i++)
+               close(i);
+}
+
 /*
  * Performs common processing for the child, such as setting up the
  * environment, closing extra file descriptors, setting the user and group
  * ids, and executing the command or shell.
  */
+#define ARGV_MAX 10
 void
 do_child(Session *s, const char *command)
 {
        extern char **environ;
        char **env;
-       char *argv[10];
+       char *argv[ARGV_MAX];
        const char *shell, *shell0, *hostname = NULL;
        struct passwd *pw = s->pw;
-       u_int i;
+       int r = 0;
 
 #ifdef AFS_KRB5
 /* Default place to look for aklog. */
@@ -1327,6 +1833,14 @@ do_child(Session *s, const char *command)
        /* remove hostkey from the child's memory */
        destroy_sensitive_data();
 
+       /* Force a password change */
+       if (s->authctxt->force_pwchange) {
+               do_setusercontext(pw);
+               child_close_fds();
+               do_pwchange(s);
+               exit(1);
+       }
+
        /* login(1) is only called if we execute the login shell */
        if (options.use_login && command != NULL)
                options.use_login = 0;
@@ -1341,30 +1855,52 @@ do_child(Session *s, const char *command)
         */
        if (!options.use_login) {
 #ifdef HAVE_OSF_SIA
-               session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
+               session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
                if (!check_quietlogin(s, command))
                        do_motd();
 #else /* HAVE_OSF_SIA */
-               do_nologin(pw);
+               /* When PAM is enabled we rely on it to do the nologin check */
+               if (!options.use_pam)
+                       do_nologin(pw);
                do_setusercontext(pw);
+               /*
+                * PAM session modules in do_setusercontext may have
+                * generated messages, so if this in an interactive
+                * login then display them too.
+                */
+               if (!check_quietlogin(s, command))
+                       display_loginmsg();
 #endif /* HAVE_OSF_SIA */
        }
 
+#ifdef USE_PAM
+       if (options.use_pam && !options.use_login && !is_pam_session_open()) {
+               debug3("PAM session not opened, exiting");
+               display_loginmsg();
+               exit(254);
+       }
+#endif
+
        /*
         * Get the shell from the password data.  An empty shell field is
         * legal, and means /bin/sh.
         */
        shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
+
+       /*
+        * Make sure $SHELL points to the shell from the password file,
+        * even if shell is overridden from login.conf
+        */
+       env = do_setup_env(s, shell);
+
 #ifdef HAVE_LOGIN_CAP
        shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
 #endif
 
-       env = do_setup_env(s, shell);
-
        /* we have to stash the hostname before we close our socket. */
        if (options.use_login)
                hostname = get_remote_name_or_ip(utmp_len,
-                   options.verify_reverse_mapping);
+                   options.use_dns);
        /*
         * Close the connection descriptors; note that this is the child, and
         * the server will still have the socket open, and it is important
@@ -1372,39 +1908,39 @@ do_child(Session *s, const char *command)
         * closed before building the environment, as we call
         * get_remote_ipaddr there.
         */
-       if (packet_get_connection_in() == packet_get_connection_out())
-               close(packet_get_connection_in());
-       else {
-               close(packet_get_connection_in());
-               close(packet_get_connection_out());
-       }
-       /*
-        * Close all descriptors related to channels.  They will still remain
-        * open in the parent.
-        */
-       /* XXX better use close-on-exec? -markus */
-       channel_close_all();
+       child_close_fds();
 
        /*
-        * Close any extra file descriptors.  Note that there may still be
-        * descriptors left by system functions.  They will be closed later.
+        * Must take new environment into use so that .ssh/rc,
+        * /etc/ssh/sshrc and xauth are run in the proper environment.
         */
-       endpwent();
+       environ = env;
 
+#if defined(KRB5) && defined(USE_AFS)
        /*
-        * Close any extra open file descriptors so that we don\'t have them
-        * hanging around in clients.  Note that we want to do this after
-        * initgroups, because at least on Solaris 2.3 it leaves file
-        * descriptors open.
+        * At this point, we check to see if AFS is active and if we have
+        * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
+        * if we can (and need to) extend the ticket into an AFS token. If
+        * we don't do this, we run into potential problems if the user's
+        * home directory is in AFS and it's not world-readable.
         */
-       for (i = 3; i < 64; i++)
-               close(i);
 
-       /*
-        * Must take new environment into use so that .ssh/rc,
-        * /etc/ssh/sshrc and xauth are run in the proper environment.
-        */
-       environ = env;
+       if (options.kerberos_get_afs_token && k_hasafs() &&
+           (s->authctxt->krb5_ctx != NULL)) {
+               char cell[64];
+
+               debug("Getting AFS token");
+
+               k_setpag();
+
+               if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
+                       krb5_afslog(s->authctxt->krb5_ctx,
+                           s->authctxt->krb5_fwd_ccache, cell, NULL);
+
+               krb5_afslog_home(s->authctxt->krb5_ctx,
+                   s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
+       }
+#endif
 
 #ifdef AFS_KRB5
 
@@ -1430,33 +1966,54 @@ do_child(Session *s, const char *command)
        }
 #endif /* AFS_KRB5 */
 
-#ifdef AFS
-       /* Try to get AFS tokens for the local cell. */
-       if (k_hasafs()) {
-               char cell[64];
-
-               if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
-                       krb_afslog(cell, 0);
-
-               krb_afslog(0, 0);
-       }
-#endif /* AFS */
+#ifdef SESSION_HOOKS
+        if (options.session_hooks_allow &&
+            options.session_hooks_startup_cmd)
+        {
+            execute_session_hook(options.session_hooks_startup_cmd,
+                                 s->authctxt,
+                                 /* startup = */ 1,
+                                 options.session_hooks_shutdown_cmd != NULL);
+        }
+#endif
 
-       /* Change current directory to the user\'s home directory. */
+       /* Change current directory to the user's home directory. */
        if (chdir(pw->pw_dir) < 0) {
-               fprintf(stderr, "Could not chdir to home directory %s: %s\n",
-                   pw->pw_dir, strerror(errno));
+               /* Suppress missing homedir warning for chroot case */
 #ifdef HAVE_LOGIN_CAP
-               if (login_getcapbool(lc, "requirehome", 0))
-                       exit(1);
+               r = login_getcapbool(lc, "requirehome", 0);
 #endif
+               if (r || options.chroot_directory == NULL)
+                       fprintf(stderr, "Could not chdir to home "
+                           "directory %s: %s\n", pw->pw_dir,
+                           strerror(errno));
+               if (r)
+                       exit(1);
        }
 
+       closefrom(STDERR_FILENO + 1);
+
        if (!options.use_login)
                do_rc_files(s, shell);
 
        /* restore SIGPIPE for child */
-       signal(SIGPIPE,  SIG_DFL);
+       signal(SIGPIPE, SIG_DFL);
+
+       if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
+               extern int optind, optreset;
+               int i;
+               char *p, *args;
+
+               setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
+               args = xstrdup(command ? command : "sftp-server");
+               for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
+                       if (i < ARGV_MAX - 1)
+                               argv[i++] = p;
+               argv[i] = NULL;
+               optind = optreset = 1;
+               __progname = argv[0];
+               exit(sftp_server_main(i, argv, s->pw));
+       }
 
        if (options.use_login) {
                launch_login(pw, hostname);
@@ -1490,7 +2047,7 @@ do_child(Session *s, const char *command)
                /* Execute the shell. */
                argv[0] = argv0;
                argv[1] = NULL;
-               execve(shell, argv, env);
+               execve(shell, argv, environ);
 
                /* Executing the shell failed. */
                perror(shell);
@@ -1504,47 +2061,84 @@ do_child(Session *s, const char *command)
        argv[1] = "-c";
        argv[2] = (char *) command;
        argv[3] = NULL;
-       execve(shell, argv, env);
+       execve(shell, argv, environ);
        perror(shell);
        exit(1);
 }
 
+void
+session_unused(int id)
+{
+       debug3("%s: session id %d unused", __func__, id);
+       if (id >= options.max_sessions ||
+           id >= sessions_nalloc) {
+               fatal("%s: insane session id %d (max %d nalloc %d)",
+                   __func__, id, options.max_sessions, sessions_nalloc);
+       }
+       bzero(&sessions[id], sizeof(*sessions));
+       sessions[id].self = id;
+       sessions[id].used = 0;
+       sessions[id].chanid = -1;
+       sessions[id].ptyfd = -1;
+       sessions[id].ttyfd = -1;
+       sessions[id].ptymaster = -1;
+       sessions[id].x11_chanids = NULL;
+       sessions[id].next_unused = sessions_first_unused;
+       sessions_first_unused = id;
+}
+
 Session *
 session_new(void)
 {
-       int i;
-       static int did_init = 0;
-       if (!did_init) {
-               debug("session_new: init");
-               for (i = 0; i < MAX_SESSIONS; i++) {
-                       sessions[i].used = 0;
+       Session *s, *tmp;
+
+       if (sessions_first_unused == -1) {
+               if (sessions_nalloc >= options.max_sessions)
+                       return NULL;
+               debug2("%s: allocate (allocated %d max %d)",
+                   __func__, sessions_nalloc, options.max_sessions);
+               tmp = xrealloc(sessions, sessions_nalloc + 1,
+                   sizeof(*sessions));
+               if (tmp == NULL) {
+                       error("%s: cannot allocate %d sessions",
+                           __func__, sessions_nalloc + 1);
+                       return NULL;
                }
-               did_init = 1;
+               sessions = tmp;
+               session_unused(sessions_nalloc++);
        }
-       for (i = 0; i < MAX_SESSIONS; i++) {
-               Session *s = &sessions[i];
-               if (! s->used) {
-                       memset(s, 0, sizeof(*s));
-                       s->chanid = -1;
-                       s->ptyfd = -1;
-                       s->ttyfd = -1;
-                       s->used = 1;
-                       s->self = i;
-                       debug("session_new: session %d", i);
-                       return s;
-               }
+
+       if (sessions_first_unused >= sessions_nalloc ||
+           sessions_first_unused < 0) {
+               fatal("%s: insane first_unused %d max %d nalloc %d",
+                   __func__, sessions_first_unused, options.max_sessions,
+                   sessions_nalloc);
        }
-       return NULL;
+
+       s = &sessions[sessions_first_unused];
+       if (s->used) {
+               fatal("%s: session %d already used",
+                   __func__, sessions_first_unused);
+       }
+       sessions_first_unused = s->next_unused;
+       s->used = 1;
+       s->next_unused = -1;
+       debug("session_new: session %d", s->self);
+
+       return s;
 }
 
 static void
 session_dump(void)
 {
        int i;
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
-               debug("dump: used %d session %d %p channel %d pid %ld",
+
+               debug("dump: used %d next_unused %d session %d %p "
+                   "channel %d pid %ld",
                    s->used,
+                   s->next_unused,
                    s->self,
                    s,
                    s->chanid,
@@ -1563,7 +2157,7 @@ session_open(Authctxt *authctxt, int chanid)
        }
        s->authctxt = authctxt;
        s->pw = authctxt->pw;
-       if (s->pw == NULL)
+       if (s->pw == NULL || !authctxt->valid)
                fatal("no user for session %d", s->self);
        debug("session_open: session %d: link with channel %d", s->self, chanid);
        s->chanid = chanid;
@@ -1574,7 +2168,7 @@ Session *
 session_by_tty(char *tty)
 {
        int i;
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
                if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
                        debug("session_by_tty: session %d tty %s", i, tty);
@@ -1590,10 +2184,11 @@ static Session *
 session_by_channel(int id)
 {
        int i;
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
                if (s->used && s->chanid == id) {
-                       debug("session_by_channel: session %d channel %d", i, id);
+                       debug("session_by_channel: session %d channel %d",
+                           i, id);
                        return s;
                }
        }
@@ -1602,12 +2197,35 @@ session_by_channel(int id)
        return NULL;
 }
 
+static Session *
+session_by_x11_channel(int id)
+{
+       int i, j;
+
+       for (i = 0; i < sessions_nalloc; i++) {
+               Session *s = &sessions[i];
+
+               if (s->x11_chanids == NULL || !s->used)
+                       continue;
+               for (j = 0; s->x11_chanids[j] != -1; j++) {
+                       if (s->x11_chanids[j] == id) {
+                               debug("session_by_x11_channel: session %d "
+                                   "channel %d", s->self, id);
+                               return s;
+                       }
+               }
+       }
+       debug("session_by_x11_channel: unknown channel %d", id);
+       session_dump();
+       return NULL;
+}
+
 static Session *
 session_by_pid(pid_t pid)
 {
        int i;
        debug("session_by_pid: pid %ld", (long)pid);
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
                if (s->used && s->pid == pid)
                        return s;
@@ -1643,12 +2261,6 @@ session_pty_req(Session *s)
                packet_disconnect("Protocol error: you already have a pty.");
                return 0;
        }
-       /* Get the time and hostname when the user last logged in. */
-       if (options.print_lastlog) {
-               s->hostname[0] = '\0';
-               s->last_login_time = get_last_login_time(s->pw->pw_uid,
-                   s->pw->pw_name, s->hostname, sizeof(s->hostname));
-       }
 
        s->term = packet_get_string(&len);
 
@@ -1669,7 +2281,8 @@ session_pty_req(Session *s)
 
        /* Allocate a pty and open it. */
        debug("Allocating pty.");
-       if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
+       if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
+           sizeof(s->tty)))) {
                if (s->term)
                        xfree(s->term);
                s->term = NULL;
@@ -1685,11 +2298,6 @@ session_pty_req(Session *s)
                n_bytes = packet_remaining();
        tty_parse_modes(s->ttyfd, &n_bytes);
 
-       /*
-        * Add a cleanup function to clear the utmp entry and record logout
-        * time in case we call fatal() (e.g., the connection gets closed).
-        */
-       fatal_add_cleanup(session_pty_cleanup, (void *)s);
        if (!use_privsep)
                pty_setowner(s->pw, s->tty);
 
@@ -1707,30 +2315,33 @@ session_subsystem_req(Session *s)
        struct stat st;
        u_int len;
        int success = 0;
-       char *cmd, *subsys = packet_get_string(&len);
-       int i;
+       char *prog, *cmd, *subsys = packet_get_string(&len);
+       u_int i;
 
        packet_check_eom();
-       log("subsystem request for %.100s", subsys);
+       logit("subsystem request for %.100s", subsys);
 
        for (i = 0; i < options.num_subsystems; i++) {
                if (strcmp(subsys, options.subsystem_name[i]) == 0) {
-                       cmd = options.subsystem_command[i];
-                       if (stat(cmd, &st) < 0) {
-                               error("subsystem: cannot stat %s: %s", cmd,
+                       prog = options.subsystem_command[i];
+                       cmd = options.subsystem_args[i];
+                       if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
+                               s->is_subsystem = SUBSYSTEM_INT_SFTP;
+                       } else if (stat(prog, &st) < 0) {
+                               error("subsystem: cannot stat %s: %s", prog,
                                    strerror(errno));
                                break;
+                       } else {
+                               s->is_subsystem = SUBSYSTEM_EXT;
                        }
                        debug("subsystem: exec() %s", cmd);
-                       s->is_subsystem = 1;
-                       do_exec(s, cmd);
-                       success = 1;
+                       success = do_exec(s, cmd) == 0;
                        break;
                }
        }
 
        if (!success)
-               log("subsystem request for %.100s failed, subsystem not found",
+               logit("subsystem request for %.100s failed, subsystem not found",
                    subsys);
 
        xfree(subsys);
@@ -1742,6 +2353,11 @@ session_x11_req(Session *s)
 {
        int success;
 
+       if (s->auth_proto != NULL || s->auth_data != NULL) {
+               error("session_x11_req: session %d: "
+                   "x11 forwarding already active", s->self);
+               return 0;
+       }
        s->single_connection = packet_get_char();
        s->auth_proto = packet_get_string(NULL);
        s->auth_data = packet_get_string(NULL);
@@ -1762,27 +2378,74 @@ static int
 session_shell_req(Session *s)
 {
        packet_check_eom();
-       do_exec(s, NULL);
-       return 1;
+       return do_exec(s, NULL) == 0;
 }
 
 static int
 session_exec_req(Session *s)
 {
-       u_int len;
+       u_int len, success;
+
        char *command = packet_get_string(&len);
        packet_check_eom();
-       do_exec(s, command);
+       success = do_exec(s, command) == 0;
        xfree(command);
+       return success;
+}
+
+static int
+session_break_req(Session *s)
+{
+
+       packet_get_int();       /* ignored */
+       packet_check_eom();
+
+       if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
+               return 0;
        return 1;
 }
 
+static int
+session_env_req(Session *s)
+{
+       char *name, *val;
+       u_int name_len, val_len, i;
+
+       name = packet_get_string(&name_len);
+       val = packet_get_string(&val_len);
+       packet_check_eom();
+
+       /* Don't set too many environment variables */
+       if (s->num_env > 128) {
+               debug2("Ignoring env request %s: too many env vars", name);
+               goto fail;
+       }
+
+       for (i = 0; i < options.num_accept_env; i++) {
+               if (match_pattern(name, options.accept_env[i])) {
+                       debug2("Setting env %d: %s=%s", s->num_env, name, val);
+                       s->env = xrealloc(s->env, s->num_env + 1,
+                           sizeof(*s->env));
+                       s->env[s->num_env].name = name;
+                       s->env[s->num_env].val = val;
+                       s->num_env++;
+                       return (1);
+               }
+       }
+       debug2("Ignoring env request %s: disallowed name", name);
+
+ fail:
+       xfree(name);
+       xfree(val);
+       return (0);
+}
+
 static int
 session_auth_agent_req(Session *s)
 {
        static int called = 0;
        packet_check_eom();
-       if (no_agent_forwarding_flag) {
+       if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
                debug("session_auth_agent_req: no_agent_forwarding_flag");
                return 0;
        }
@@ -1801,7 +2464,7 @@ session_input_channel_req(Channel *c, const char *rtype)
        Session *s;
 
        if ((s = session_by_channel(c->self)) == NULL) {
-               log("session_input_channel_req: no session %d req %.100s",
+               logit("session_input_channel_req: no session %d req %.100s",
                    c->self, rtype);
                return 0;
        }
@@ -1817,23 +2480,28 @@ session_input_channel_req(Channel *c, const char *rtype)
                } else if (strcmp(rtype, "exec") == 0) {
                        success = session_exec_req(s);
                } else if (strcmp(rtype, "pty-req") == 0) {
-                       success =  session_pty_req(s);
+                       success = session_pty_req(s);
                } else if (strcmp(rtype, "x11-req") == 0) {
                        success = session_x11_req(s);
                } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
                        success = session_auth_agent_req(s);
                } else if (strcmp(rtype, "subsystem") == 0) {
                        success = session_subsystem_req(s);
+               } else if (strcmp(rtype, "env") == 0) {
+                       success = session_env_req(s);
                }
        }
        if (strcmp(rtype, "window-change") == 0) {
                success = session_window_change_req(s);
+       } else if (strcmp(rtype, "break") == 0) {
+               success = session_break_req(s);
        }
+
        return success;
 }
 
 void
-session_set_fds(Session *s, int fdin, int fdout, int fderr)
+session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
 {
        if (!compat20)
                fatal("session_set_fds: called for proto != 2.0");
@@ -1843,11 +2511,16 @@ session_set_fds(Session *s, int fdin, int fdout, int fderr)
         */
        if (s->chanid == -1)
                fatal("no channel for session %d", s->self);
+       if (options.hpn_disabled)
        channel_set_fds(s->chanid,
            fdout, fdin, fderr,
            fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
-           1,
-           CHAN_SES_WINDOW_DEFAULT);
+           1, is_tty, CHAN_SES_WINDOW_DEFAULT);
+       else 
+               channel_set_fds(s->chanid,
+                   fdout, fdin, fderr,
+                   fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
+                   1, is_tty, options.hpn_buffer_size);
 }
 
 /*
@@ -1855,10 +2528,8 @@ session_set_fds(Session *s, int fdin, int fdout, int fderr)
  * (e.g., due to a dropped connection).
  */
 void
-session_pty_cleanup2(void *session)
+session_pty_cleanup2(Session *s)
 {
-       Session *s = session;
-
        if (s == NULL) {
                error("session_pty_cleanup: no session");
                return;
@@ -1881,17 +2552,18 @@ session_pty_cleanup2(void *session)
         * the pty cleanup, so that another process doesn't get this pty
         * while we're still cleaning up.
         */
-       if (close(s->ptymaster) < 0)
-               error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
+       if (s->ptymaster != -1 && close(s->ptymaster) < 0)
+               error("close(s->ptymaster/%d): %s",
+                   s->ptymaster, strerror(errno));
 
        /* unlink pty from session */
        s->ttyfd = -1;
 }
 
 void
-session_pty_cleanup(void *session)
+session_pty_cleanup(Session *s)
 {
-       PRIVSEP(session_pty_cleanup2(session));
+       PRIVSEP(session_pty_cleanup2(s));
 }
 
 static char *
@@ -1915,6 +2587,62 @@ sig2name(int sig)
        return "SIG@openssh.com";
 }
 
+static void
+session_close_x11(int id)
+{
+       Channel *c;
+
+       if ((c = channel_by_id(id)) == NULL) {
+               debug("session_close_x11: x11 channel %d missing", id);
+       } else {
+               /* Detach X11 listener */
+               debug("session_close_x11: detach x11 channel %d", id);
+               channel_cancel_cleanup(id);
+               if (c->ostate != CHAN_OUTPUT_CLOSED)
+                       chan_mark_dead(c);
+       }
+}
+
+static void
+session_close_single_x11(int id, void *arg)
+{
+       Session *s;
+       u_int i;
+
+       debug3("session_close_single_x11: channel %d", id);
+       channel_cancel_cleanup(id);
+       if ((s = session_by_x11_channel(id)) == NULL)
+               fatal("session_close_single_x11: no x11 channel %d", id);
+       for (i = 0; s->x11_chanids[i] != -1; i++) {
+               debug("session_close_single_x11: session %d: "
+                   "closing channel %d", s->self, s->x11_chanids[i]);
+               /*
+                * The channel "id" is already closing, but make sure we
+                * close all of its siblings.
+                */
+               if (s->x11_chanids[i] != id)
+                       session_close_x11(s->x11_chanids[i]);
+       }
+       xfree(s->x11_chanids);
+       s->x11_chanids = NULL;
+       if (s->display) {
+               xfree(s->display);
+               s->display = NULL;
+       }
+       if (s->auth_proto) {
+               xfree(s->auth_proto);
+               s->auth_proto = NULL;
+       }
+       if (s->auth_data) {
+               xfree(s->auth_data);
+               s->auth_data = NULL;
+       }
+       if (s->auth_display) {
+               xfree(s->auth_display);
+               s->auth_display = NULL;
+       }
+}
+
 static void
 session_exit_message(Session *s, int status)
 {
@@ -1934,7 +2662,7 @@ session_exit_message(Session *s, int status)
                channel_request_start(s->chanid, "exit-signal", 0);
                packet_put_cstring(sig2name(WTERMSIG(status)));
 #ifdef WCOREDUMP
-               packet_put_char(WCOREDUMP(status));
+               packet_put_char(WCOREDUMP(status)? 1 : 0);
 #else /* WCOREDUMP */
                packet_put_char(0);
 #endif /* WCOREDUMP */
@@ -1948,7 +2676,14 @@ session_exit_message(Session *s, int status)
 
        /* disconnect channel */
        debug("session_exit_message: release channel %d", s->chanid);
-       channel_cancel_cleanup(s->chanid);
+
+       /*
+        * Adjust cleanup callback attachment to send close messages when
+        * the channel gets EOF. The session will be then be closed
+        * by session_close_by_channel when the childs close their fds.
+        */
+       channel_register_cleanup(c->self, session_close_by_channel, 1);
+
        /*
         * emulate a write failure with 'chan_write_failed', nobody will be
         * interested in data we write.
@@ -1957,29 +2692,37 @@ session_exit_message(Session *s, int status)
         */
        if (c->ostate != CHAN_OUTPUT_CLOSED)
                chan_write_failed(c);
-       s->chanid = -1;
 }
 
 void
 session_close(Session *s)
 {
+       u_int i;
+
        debug("session_close: session %d pid %ld", s->self, (long)s->pid);
-       if (s->ttyfd != -1) {
-               fatal_remove_cleanup(session_pty_cleanup, (void *)s);
+       if (s->ttyfd != -1)
                session_pty_cleanup(s);
-       }
        if (s->term)
                xfree(s->term);
        if (s->display)
                xfree(s->display);
+       if (s->x11_chanids)
+               xfree(s->x11_chanids);
        if (s->auth_display)
                xfree(s->auth_display);
        if (s->auth_data)
                xfree(s->auth_data);
        if (s->auth_proto)
                xfree(s->auth_proto);
-       s->used = 0;
+       if (s->env != NULL) {
+               for (i = 0; i < s->num_env; i++) {
+                       xfree(s->env[i].name);
+                       xfree(s->env[i].val);
+               }
+               xfree(s->env);
+       }
        session_proctitle(s);
+       session_unused(s->self);
 }
 
 void
@@ -1993,7 +2736,9 @@ session_close_by_pid(pid_t pid, int status)
        }
        if (s->chanid != -1)
                session_exit_message(s, status);
-       session_close(s);
+       if (s->ttyfd != -1)
+               session_pty_cleanup(s);
+       s->pid = 0;
 }
 
 /*
@@ -2004,6 +2749,8 @@ void
 session_close_by_channel(int id, void *arg)
 {
        Session *s = session_by_channel(id);
+       u_int i;
+
        if (s == NULL) {
                debug("session_close_by_channel: no session for id %d", id);
                return;
@@ -2016,14 +2763,21 @@ session_close_by_channel(int id, void *arg)
                 * delay detach of session, but release pty, since
                 * the fd's to the child are already closed
                 */
-               if (s->ttyfd != -1) {
-                       fatal_remove_cleanup(session_pty_cleanup, (void *)s);
+               if (s->ttyfd != -1)
                        session_pty_cleanup(s);
-               }
                return;
        }
        /* detach by removing callback */
        channel_cancel_cleanup(s->chanid);
+
+       /* Close any X11 listeners associated with this session */
+       if (s->x11_chanids != NULL) {
+               for (i = 0; s->x11_chanids[i] != -1; i++) {
+                       session_close_x11(s->x11_chanids[i]);
+                       s->x11_chanids[i] = -1;
+               }
+       }
+
        s->chanid = -1;
        session_close(s);
 }
@@ -2032,7 +2786,7 @@ void
 session_destroy_all(void (*closefunc)(Session *))
 {
        int i;
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
                if (s->used) {
                        if (closefunc != NULL)
@@ -2048,13 +2802,22 @@ session_tty_list(void)
 {
        static char buf[1024];
        int i;
+       char *cp;
+
        buf[0] = '\0';
-       for (i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < sessions_nalloc; i++) {
                Session *s = &sessions[i];
                if (s->used && s->ttyfd != -1) {
+
+                       if (strncmp(s->tty, "/dev/", 5) != 0) {
+                               cp = strrchr(s->tty, '/');
+                               cp = (cp == NULL) ? s->tty : cp + 1;
+                       } else
+                               cp = s->tty + 5;
+
                        if (buf[0] != '\0')
                                strlcat(buf, ",", sizeof buf);
-                       strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
+                       strlcat(buf, cp, sizeof buf);
                }
        }
        if (buf[0] == '\0')
@@ -2077,6 +2840,7 @@ session_setup_x11fwd(Session *s)
        struct stat st;
        char display[512], auth_display[512];
        char hostname[MAXHOSTNAMELEN];
+       u_int i;
 
        if (no_x11_forwarding_flag) {
                packet_send_debug("X11 forwarding disabled in user configuration file.");
@@ -2102,10 +2866,14 @@ session_setup_x11fwd(Session *s)
        }
        if (x11_create_display_inet(options.x11_display_offset,
            options.x11_use_localhost, s->single_connection,
-           &s->display_number) == -1) {
+           &s->display_number, &s->x11_chanids) == -1) {
                debug("x11_create_display_inet failed.");
                return 0;
        }
+       for (i = 0; s->x11_chanids[i] != -1; i++) {
+               channel_register_cleanup(s->x11_chanids[i],
+                   session_close_single_x11, 0);
+       }
 
        /* Set up a suitable value for the DISPLAY variable. */
        if (gethostname(hostname, sizeof(hostname)) < 0)
@@ -2151,7 +2919,55 @@ static void
 do_authenticated2(Authctxt *authctxt)
 {
        server_loop2(authctxt);
-#if defined(GSSAPI)
-       ssh_gssapi_cleanup_creds(NULL);
+}
+
+void
+do_cleanup(Authctxt *authctxt)
+{
+       static int called = 0;
+
+       debug("do_cleanup");
+
+       /* no cleanup if we're in the child for login shell */
+       if (is_child)
+               return;
+
+       /* avoid double cleanup */
+       if (called)
+               return;
+       called = 1;
+
+       if (authctxt == NULL)
+               return;
+
+#ifdef USE_PAM
+       if (options.use_pam) {
+               sshpam_cleanup();
+               sshpam_thread_cleanup();
+       }
+#endif
+
+       if (!authctxt->authenticated)
+               return;
+
+#ifdef KRB5
+       if (options.kerberos_ticket_cleanup &&
+           authctxt->krb5_ctx)
+               krb5_cleanup_proc(authctxt);
 #endif
+
+#ifdef GSSAPI
+       if (compat20 && options.gss_cleanup_creds)
+               ssh_gssapi_cleanup_creds();
+#endif
+
+       /* remove agent socket */
+       auth_sock_cleanup_proc(authctxt->pw);
+
+       /*
+        * Cleanup ptys/utmp only if privsep is disabled,
+        * or if running in monitor.
+        */
+       if (!use_privsep || mm_is_monitor())
+               session_destroy_all(session_pty_cleanup2);
 }
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