]> andersk Git - openssh.git/blobdiff - session.c
remove acconfig.h
[openssh.git] / session.c
index 35e49c74eda252c919e03bd1eb771ffd9f5c9bd4..db8722f47ceb7f9cc0165ad743a1b3b36313adb8 100644 (file)
--- a/session.c
+++ b/session.c
@@ -9,7 +9,7 @@
  * called by a name other than "ssh" or "Secure Shell".
  *
  * SSH2 support by Markus Friedl.
- * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,7 +33,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.94 2001/06/23 15:12:20 itojun Exp $");
+RCSID("$OpenBSD: session.c,v 1.186 2005/07/25 11:59:40 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -42,7 +42,7 @@ RCSID("$OpenBSD: session.c,v 1.94 2001/06/23 15:12:20 itojun Exp $");
 #include "sshpty.h"
 #include "packet.h"
 #include "buffer.h"
-#include "mpaux.h"
+#include "match.h"
 #include "uidswap.h"
 #include "compat.h"
 #include "channels.h"
@@ -56,85 +56,38 @@ RCSID("$OpenBSD: session.c,v 1.94 2001/06/23 15:12:20 itojun Exp $");
 #include "serverloop.h"
 #include "canohost.h"
 #include "session.h"
+#include "kex.h"
+#include "monitor_wrap.h"
 
-#ifdef WITH_IRIX_PROJECT
-#include <proj.h>
-#endif /* WITH_IRIX_PROJECT */
-#ifdef WITH_IRIX_JOBS
-#include <sys/resource.h>
+#if defined(KRB5) && defined(USE_AFS)
+#include <kafs.h>
 #endif
-#ifdef WITH_IRIX_AUDIT
-#include <sat.h>
-#endif /* WITH_IRIX_AUDIT */
 
-#if defined(HAVE_USERSEC_H)
-#include <usersec.h>
+#ifdef GSSAPI
+#include "ssh-gss.h"
 #endif
 
-#ifdef HAVE_CYGWIN
-#include <windows.h>
-#include <sys/cygwin.h>
-#define is_winnt       (GetVersion() < 0x80000000)
-#endif
-
-/* AIX limits */
-#if defined(HAVE_GETUSERATTR) && !defined(S_UFSIZE_HARD) && defined(S_UFSIZE)
-# define S_UFSIZE_HARD  S_UFSIZE "_hard"
-# define S_UCPU_HARD  S_UCPU "_hard"
-# define S_UDATA_HARD  S_UDATA "_hard"
-# define S_USTACK_HARD  S_USTACK "_hard"
-# define S_URSS_HARD  S_URSS "_hard"
-# define S_UCORE_HARD  S_UCORE "_hard"
-# define S_UNOFILE_HARD        S_UNOFILE "_hard"
-#endif
-
-#ifdef _AIX
-# include <uinfo.h>
-#endif
-
-/* types */
-
-#define TTYSZ 64
-typedef struct Session Session;
-struct Session {
-       int     used;
-       int     self;
-       struct  passwd *pw;
-       pid_t   pid;
-       /* tty */
-       char    *term;
-       int     ptyfd, ttyfd, ptymaster;
-       int     row, col, xpixel, ypixel;
-       char    tty[TTYSZ];
-       /* X11 */
-       char    *display;
-       int     screen;
-       char    *auth_proto;
-       char    *auth_data;
-       int     single_connection;
-       /* proto 2 */
-       int     chanid;
-       int     is_subsystem;
-};
-
 /* func */
 
 Session *session_new(void);
-void  session_set_fds(Session *, int, int, int);
-static void   session_pty_cleanup(void *);
-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 *);
-void  do_login(Session *, const char *);
-void  do_child(Session *, const char *);
+void   session_set_fds(Session *, 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 *);
+void   do_login(Session *, const char *);
+#ifdef LOGIN_NEEDS_UTMPX
+static void    do_pre_login(Session *s);
+#endif
+void   do_child(Session *, const char *);
 void   do_motd(void);
+int    check_quietlogin(Session *, const char *);
 
 static void do_authenticated1(Authctxt *);
 static void do_authenticated2(Authctxt *);
-static void session_close(Session *);
+
 static int session_pty_req(Session *);
 
 /* import */
@@ -145,6 +98,7 @@ 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;
@@ -153,18 +107,108 @@ const char *original_command = NULL;
 #define MAX_SESSIONS 10
 Session        sessions[MAX_SESSIONS];
 
-#ifdef WITH_AIXAUTHENTICATE
-/* AIX's lastlogin message, set in auth1.c */
-char *aixloginmsg;
-#endif /* WITH_AIXAUTHENTICATE */
-
 #ifdef HAVE_LOGIN_CAP
-static login_cap_t *lc;
+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;
+
+/* removes the agent forwarding socket */
+
+static void
+auth_sock_cleanup_proc(struct passwd *pw)
+{
+       if (auth_sock_name != NULL) {
+               temporarily_use_uid(pw);
+               unlink(auth_sock_name);
+               rmdir(auth_sock_dir);
+               auth_sock_name = NULL;
+               restore_uid();
+       }
+}
+
+static int
+auth_input_request_forwarding(struct passwd * pw)
+{
+       Channel *nc;
+       int sock;
+       struct sockaddr_un sunaddr;
+
+       if (auth_sock_name != NULL) {
+               error("authentication forwarding requested twice.");
+               return 0;
+       }
+
+       /* Temporarily drop privileged uid for mkdir/bind. */
+       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-XXXXXXXXXX", MAXPATHLEN);
+
+       /* 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;
+       }
+       snprintf(auth_sock_name, MAXPATHLEN, "%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));
+
+       /* 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));
+
+       /* Restore the privileged uid. */
+       restore_uid();
+
+       /* Start listening on the socket. */
+       if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
+               packet_disconnect("listen: %.100s", strerror(errno));
+
+       /* Allocate a channel for the authentication agent socket. */
+       nc = channel_new("auth socket",
+           SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
+           CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
+           0, "auth socket", 1);
+       strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
+       return 1;
+}
+
+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)
 {
+       setproctitle("%s", authctxt->pw->pw_name);
+
        /*
         * Cancel the alarm we set to limit the time taken for
         * authentication.
@@ -174,18 +218,6 @@ do_authenticated(Authctxt *authctxt)
                close(startup_pipe);
                startup_pipe = -1;
        }
-#if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
-       if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
-               error("unable to get login class");
-               return;
-       }
-#ifdef BSD_AUTH
-       if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
-               packet_disconnect("Approval failure for %s",
-                   authctxt->pw->pw_name);
-       }
-#endif
-#endif
        /* setup the channel layer */
        if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
                channel_permit_all_opens();
@@ -195,9 +227,7 @@ do_authenticated(Authctxt *authctxt)
        else
                do_authenticated1(authctxt);
 
-       /* remove agent socket */
-       if (auth_get_socket_name())
-               auth_sock_cleanup_proc(authctxt->pw);
+       do_cleanup(authctxt);
 }
 
 /*
@@ -211,11 +241,16 @@ do_authenticated1(Authctxt *authctxt)
 {
        Session *s;
        char *command;
-       int success, type, plen, screen_flag;
-       int compression_level = 0, enable_compression_after_reply = 0;
-       u_int proto_len, data_len, dlen;
+       int success, type, screen_flag;
+       int enable_compression_after_reply = 0;
+       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;
 
        /*
@@ -226,16 +261,20 @@ do_authenticated1(Authctxt *authctxt)
                success = 0;
 
                /* Get a packet from the client. */
-               type = packet_read(&plen);
+               type = packet_read();
 
                /* Process the packet. */
                switch (type) {
                case SSH_CMSG_REQUEST_COMPRESSION:
-                       packet_integrity_check(plen, 4, type);
                        compression_level = packet_get_int();
+                       packet_check_eom();
                        if (compression_level < 1 || compression_level > 9) {
-                               packet_send_debug("Received illegal compression level %d.",
-                                    compression_level);
+                               packet_send_debug("Received invalid compression level %d.",
+                                   compression_level);
+                               break;
+                       }
+                       if (options.compression == COMP_NONE) {
+                               debug2("compression disabled");
                                break;
                        }
                        /* Enable compression after we have responded with SUCCESS. */
@@ -263,7 +302,7 @@ do_authenticated1(Authctxt *authctxt)
                        } else {
                                s->screen = 0;
                        }
-                       packet_done();
+                       packet_check_eom();
                        success = session_setup_x11fwd(s);
                        if (!success) {
                                xfree(s->auth_proto);
@@ -311,7 +350,7 @@ do_authenticated1(Authctxt *authctxt)
                        } else {
                                do_exec(s, NULL);
                        }
-                       packet_done();
+                       packet_check_eom();
                        session_close(s);
                        return;
 
@@ -320,7 +359,7 @@ 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();
@@ -342,7 +381,7 @@ do_authenticated1(Authctxt *authctxt)
 void
 do_exec_no_pty(Session *s, const char *command)
 {
-       int pid;
+       pid_t pid;
 
 #ifdef USE_PIPES
        int pin[2], pout[2], perr[2];
@@ -364,12 +403,14 @@ do_exec_no_pty(Session *s, const char *command)
        session_proctitle(s);
 
 #if defined(USE_PAM)
-       do_pam_session(s->pw->pw_name, NULL);
-       do_pam_setcred(1);
+       if (options.use_pam && !use_privsep)
+               do_pam_setcred(1);
 #endif /* USE_PAM */
 
        /* Fork the child. */
        if ((pid = fork()) == 0) {
+               is_child = 1;
+
                /* Child.  Reinitialize the log since the pid has changed. */
                log_init(__progname, options.log_level, options.log_facility, log_stderr);
 
@@ -417,10 +458,17 @@ do_exec_no_pty(Session *s, const char *command)
                        perror("dup2 stderr");
 #endif /* USE_PIPES */
 
+#ifdef _UNICOS
+               cray_init_job(s->pw); /* set up cray jid and tmpdir */
+#endif
+
                /* Do processing for the child (exec command etc). */
                do_child(s, command);
                /* NOTREACHED */
        }
+#ifdef _UNICOS
+       signal(WJSIGNAL, cray_job_termination_handler);
+#endif /* _UNICOS */
 #ifdef HAVE_CYGWIN
        if (is_winnt)
                cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
@@ -437,7 +485,11 @@ 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]);
        } else {
                /* Enter the interactive session. */
                server_loop(pid, pin[1], pout[0], perr[0]);
@@ -448,6 +500,13 @@ do_exec_no_pty(Session *s, const char *command)
        close(inout[0]);
        close(err[0]);
 
+       /*
+        * 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);
+
        /*
         * Enter the interactive session.  Note: server_loop must be able to
         * handle the case that fdin and fdout are the same.
@@ -479,40 +538,44 @@ do_exec_pty(Session *s, const char *command)
        ttyfd = s->ttyfd;
 
 #if defined(USE_PAM)
-       do_pam_session(s->pw->pw_name, s->tty);
-       do_pam_setcred(1);
+       if (options.use_pam) {
+               do_pam_set_tty(s->tty);
+               if (!use_privsep)
+                       do_pam_setcred(1);
+       }
 #endif
 
        /* Fork the child. */
        if ((pid = fork()) == 0) {
+               is_child = 1;
+
                /* Child.  Reinitialize the log because the pid has changed. */
                log_init(__progname, options.log_level, options.log_facility, log_stderr);
-
                /* Close the master side of the pseudo tty. */
                close(ptyfd);
 
                /* Make the pseudo tty our controlling tty. */
                pty_make_controlling_tty(&ttyfd, s->tty);
 
-               /* Redirect stdin from the pseudo tty. */
-               if (dup2(ttyfd, fileno(stdin)) < 0)
-                       error("dup2 stdin failed: %.100s", strerror(errno));
-
-               /* Redirect stdout to the pseudo tty. */
-               if (dup2(ttyfd, fileno(stdout)) < 0)
-                       error("dup2 stdin failed: %.100s", strerror(errno));
-
-               /* Redirect stderr to the pseudo tty. */
-               if (dup2(ttyfd, fileno(stderr)) < 0)
-                       error("dup2 stdin failed: %.100s", strerror(errno));
+               /* Redirect stdin/stdout/stderr from the pseudo tty. */
+               if (dup2(ttyfd, 0) < 0)
+                       error("dup2 stdin: %s", strerror(errno));
+               if (dup2(ttyfd, 1) < 0)
+                       error("dup2 stdout: %s", strerror(errno));
+               if (dup2(ttyfd, 2) < 0)
+                       error("dup2 stderr: %s", strerror(errno));
 
                /* Close the extra descriptor for the pseudo tty. */
                close(ttyfd);
 
                /* record login, etc. similar to login(1) */
 #ifndef HAVE_OSF_SIA
-               if (!(options.use_login && command == NULL))
+               if (!(options.use_login && command == NULL)) {
+#ifdef _UNICOS
+                       cray_init_job(s->pw); /* set up cray jid and tmpdir */
+#endif /* _UNICOS */
                        do_login(s, command);
+               }
 # ifdef LOGIN_NEEDS_UTMPX
                else
                        do_pre_login(s);
@@ -523,6 +586,9 @@ do_exec_pty(Session *s, const char *command)
                do_child(s, command);
                /* NOTREACHED */
        }
+#ifdef _UNICOS
+       signal(WJSIGNAL, cray_job_termination_handler);
+#endif /* _UNICOS */
 #ifdef HAVE_CYGWIN
        if (is_winnt)
                cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
@@ -560,7 +626,7 @@ do_exec_pty(Session *s, const char *command)
 }
 
 #ifdef LOGIN_NEEDS_UTMPX
-void
+static void
 do_pre_login(Session *s)
 {
        socklen_t fromlen;
@@ -572,18 +638,18 @@ do_pre_login(Session *s)
         * 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);
                }
        }
 
        record_utmp_only(pid, s->tty, s->pw->pw_name,
-           get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
-           (struct sockaddr *)&from);
+           get_remote_name_or_ip(utmp_len, options.use_dns),
+           (struct sockaddr *)&from, fromlen);
 }
 #endif
 
@@ -600,47 +666,39 @@ do_exec(Session *s, const char *command)
                debug("Forced command '%.900s'", command);
        }
 
+#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);
        else
                do_exec_no_pty(s, command);
 
        original_command = NULL;
-}
 
-/*
- * Check for quiet login, either .hushlogin or command given.
- */
-static int
-check_quietlogin(Session *s, const char *command)
-{
-       char buf[256];
-       struct passwd * pw = s->pw;
-       struct stat st;
-
-       /* Return 1 if .hushlogin exists or a command given. */
-       if (command != NULL)
-               return 1;
-       snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
-#ifdef HAVE_LOGIN_CAP
-       if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
-               return 1;
-#else
-       if (stat(buf, &st) >= 0)
-               return 1;
-#endif
-       return 0;
+       /*
+        * 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);
 }
 
 /* administrative, login(1)-like work */
 void
 do_login(Session *s, const char *command)
 {
-       char *time_string;
-       char hostname[MAXHOSTNAMELEN];
        socklen_t fromlen;
        struct sockaddr_storage from;
-       time_t last_login_time;
        struct passwd * pw = s->pw;
        pid_t pid = getpid();
 
@@ -649,59 +707,39 @@ 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);
                }
        }
 
-       /* Get the time and hostname when the user last logged in. */
-       if (options.print_lastlog) {
-               hostname[0] = '\0';
-               last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
-                   hostname, sizeof(hostname));
-       }
-
        /* Record that there was a login on that tty from the remote host. */
-       record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
-           get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
-           (struct sockaddr *)&from);
+       if (!use_privsep)
+               record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
+                   get_remote_name_or_ip(utmp_len,
+                   options.use_dns),
+                   (struct sockaddr *)&from, fromlen);
 
 #ifdef USE_PAM
        /*
         * 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 */
-
-       if (options.print_lastlog && last_login_time != 0) {
-               time_string = ctime(&last_login_time);
-               if (strchr(time_string, '\n'))
-                       *strchr(time_string, '\n') = 0;
-               if (strcmp(hostname, "") == 0)
-                       printf("Last login: %s\r\n", time_string);
-               else
-                       printf("Last login: %s from %s\r\n", time_string, hostname);
-       }
+       display_loginmsg();
 
        do_motd();
 }
@@ -730,16 +768,52 @@ do_motd(void)
        }
 }
 
+
+/*
+ * Check for quiet login, either .hushlogin or command given.
+ */
+int
+check_quietlogin(Session *s, const char *command)
+{
+       char buf[256];
+       struct passwd *pw = s->pw;
+       struct stat st;
+
+       /* Return 1 if .hushlogin exists or a command given. */
+       if (command != NULL)
+               return 1;
+       snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
+#ifdef HAVE_LOGIN_CAP
+       if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
+               return 1;
+#else
+       if (stat(buf, &st) >= 0)
+               return 1;
+#endif
+       return 0;
+}
+
 /*
  * Sets the value of the given variable in the environment.  If the variable
  * already exists, its value is overriden.
  */
-static void
+void
 child_set_env(char ***envp, u_int *envsizep, const char *name,
-             const char *value)
+       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
@@ -756,9 +830,13 @@ child_set_env(char ***envp, u_int *envsizep, const char *name,
                xfree(env[i]);
        } else {
                /* New variable.  Expand if necessary. */
-               if (i >= (*envsizep) - 1) {
-                       (*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;
@@ -777,17 +855,20 @@ child_set_env(char ***envp, u_int *envsizep, const char *name,
  */
 static void
 read_environment_file(char ***env, u_int *envsize,
-                     const char *filename)
+       const char *filename)
 {
        FILE *f;
        char buf[4096];
        char *cp, *value;
+       u_int lineno = 0;
 
        f = fopen(filename, "r");
        if (!f)
                return;
 
        while (fgets(buf, sizeof(buf), f)) {
+               if (++lineno > 1000)
+                       fatal("Too many lines in environment file %s", filename);
                for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
                        ;
                if (!*cp || *cp == '#' || *cp == '\n')
@@ -796,7 +877,8 @@ read_environment_file(char ***env, u_int *envsize,
                        *strchr(cp, '\n') = '\0';
                value = strchr(cp, '=');
                if (value == NULL) {
-                       fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
+                       fprintf(stderr, "Bad line %u in %.100s\n", lineno,
+                           filename);
                        continue;
                }
                /*
@@ -810,400 +892,195 @@ read_environment_file(char ***env, u_int *envsize,
        fclose(f);
 }
 
-#ifdef USE_PAM
+#ifdef HAVE_ETC_DEFAULT_LOGIN
 /*
- * Sets any environment variables which have been specified by PAM
+ * Return named variable from specified environment, or NULL if not present.
  */
-void do_pam_environment(char ***env, int *envsize)
+static char *
+child_get_env(char **env, const char *name)
 {
-       char *equals, var_name[512], var_val[512];
-       char **pam_env;
        int i;
+       size_t len;
 
-       if ((pam_env = fetch_pam_environment()) == NULL)
-               return;
+       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;
+}
 
-       for(i = 0; pam_env[i] != NULL; i++) {
-               if ((equals = strstr(pam_env[i], "=")) == NULL)
-                       continue;
+/*
+ * 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 (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
-                       memset(var_name, '\0', sizeof(var_name));
-                       memset(var_val, '\0', sizeof(var_val));
+       if (tmpenv == NULL)
+               return;
 
-                       strncpy(var_name, pam_env[i], equals - pam_env[i]);
-                       strcpy(var_val, equals + 1);
+       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);
 
-                       debug3("PAM environment: %s=%s", var_name, var_val);
+       if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
+               if (sscanf(var, "%5lo", &mask) == 1)
+                       umask((mode_t)mask);
 
-                       child_set_env(env, envsize, var_name, var_val);
-               }
-       }
+       for (i = 0; tmpenv[i] != NULL; i++)
+               xfree(tmpenv[i]);
+       xfree(tmpenv);
 }
-#endif /* USE_PAM */
+#endif /* HAVE_ETC_DEFAULT_LOGIN */
 
-#ifdef HAVE_CYGWIN
-void copy_environment(char ***env, int *envsize)
+void
+copy_environment(char **source, char ***env, u_int *envsize)
 {
-       char *equals, var_name[512], var_val[512];
+       char *var_name, *var_val;
        int i;
 
-       for(i = 0; environ[i] != NULL; i++) {
-               if ((equals = strstr(environ[i], "=")) == NULL)
-                       continue;
-
-               if (strlen(environ[i]) < (sizeof(var_name) - 1)) {
-                       memset(var_name, '\0', sizeof(var_name));
-                       memset(var_val, '\0', sizeof(var_val));
+       if (source == NULL)
+               return;
 
-                       strncpy(var_name, environ[i], equals - environ[i]);
-                       strcpy(var_val, equals + 1);
+       for(i = 0; source[i] != NULL; i++) {
+               var_name = xstrdup(source[i]);
+               if ((var_val = strstr(var_name, "=")) == NULL) {
+                       xfree(var_name);
+                       continue;
+               }
+               *var_val++ = '\0';
 
-                       debug3("Copy environment: %s=%s", var_name, var_val);
+               debug3("Copy environment: %s=%s", var_name, var_val);
+               child_set_env(env, envsize, var_name, var_val);
 
-                       child_set_env(env, envsize, var_name, var_val);
-               }
+               xfree(var_name);
        }
 }
-#endif
 
-#if defined(HAVE_GETUSERATTR)
-/*
- * AIX-specific login initialisation
- */
-void set_limit(char *user, char *soft, char *hard, int resource, int mult)
+static char **
+do_setup_env(Session *s, const char *shell)
 {
-       struct rlimit rlim;
-       int slim, hlim;
-
-       getrlimit(resource, &rlim);
-
-       slim = 0;
-       if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
-               if (slim < 0) {
-                       rlim.rlim_cur = RLIM_INFINITY;
-               } else if (slim != 0) {
-                       /* See the wackiness below */
-                       if (rlim.rlim_cur == slim * mult)
-                               slim = 0;
-                       else
-                               rlim.rlim_cur = slim * mult;
-               }
-       }
+       char buf[256];
+       u_int i, envsize;
+       char **env, *laddr, *path = NULL;
+       struct passwd *pw = s->pw;
 
-       hlim = 0;
-       if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
-               if (hlim < 0) {
-                       rlim.rlim_max = RLIM_INFINITY;
-               } else if (hlim != 0) {
-                       rlim.rlim_max = hlim * mult;
-               }
-       }
+       /* Initialize the environment. */
+       envsize = 100;
+       env = xmalloc(envsize * sizeof(char *));
+       env[0] = NULL;
 
+#ifdef HAVE_CYGWIN
        /*
-        * XXX For cpu and fsize the soft limit is set to the hard limit
-        * if the hard limit is left at its default value and the soft limit
-        * is changed from its default value, either by requesting it
-        * (slim == 0) or by setting it to the current default.  At least
-        * that's how rlogind does it.  If you're confused you're not alone.
-        * Bug or feature? AIX 4.3.1.2
+        * The Windows environment contains some setting which are
+        * important for a running system. They must not be dropped.
         */
-       if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
-           && hlim == 0 && slim != 0)
-               rlim.rlim_max = rlim.rlim_cur;
-       /* A specified hard limit limits the soft limit */
-       else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
-               rlim.rlim_cur = rlim.rlim_max;
-       /* A soft limit can increase a hard limit */
-       else if (rlim.rlim_cur > rlim.rlim_max)
-               rlim.rlim_max = rlim.rlim_cur;
-
-       if (setrlimit(resource, &rlim) != 0)
-               error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
-}
+       {
+               char **p;
 
-void set_limits_from_userattr(char *user)
-{
-       int mask;
-       char buf[16];
-
-       set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
-       set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
-       set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
-       set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
-       set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
-       set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
-#if defined(S_UNOFILE)
-       set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
+               p = fetch_windows_environment();
+               copy_environment(p, &env, &envsize);
+               free_windows_environment(p);
+       }
 #endif
 
-       if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
-               /* Convert decimal to octal */
-               (void) snprintf(buf, sizeof(buf), "%d", mask);
-               if (sscanf(buf, "%o", &mask) == 1)
-                       umask(mask);
-       }
-}
-#endif /* defined(HAVE_GETUSERATTR) */
+#ifdef GSSAPI
+       /* Allow any GSSAPI methods that we've used to alter
+        * the childs environment as they see fit
+        */
+       ssh_gssapi_do_child(&env, &envsize);
+#endif
 
-/*
- * 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.
- */
-void
-do_child(Session *s, const char *command)
-{
-       const char *shell, *hostname = NULL, *cp = NULL;
-       struct passwd * pw = s->pw;
-       char buf[256];
-       char cmd[1024];
-       FILE *f = NULL;
-       u_int envsize, i;
-       char **env;
-       extern char **environ;
-       struct stat st;
-       char *argv[10];
-       int do_xauth;
-#ifdef WITH_IRIX_PROJECT
-       prid_t projid;
-#endif /* WITH_IRIX_PROJECT */
-#ifdef WITH_IRIX_JOBS
-       jid_t jid = 0;
-#else
-#ifdef WITH_IRIX_ARRAY
-       int jid = 0;
-#endif /* WITH_IRIX_ARRAY */
-#endif /* WITH_IRIX_JOBS */
+       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);
 
-       do_xauth =
-           s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
+               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)
+                       child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
+               else
+                       child_set_env(&env, &envsize, "PATH", getenv("PATH"));
+#else /* HAVE_LOGIN_CAP */
+# ifndef HAVE_CYGWIN
+               /*
+                * There's no standard path on Windows. The path contains
+                * important components pointing to the system directories,
+                * needed for loading shared libraries. So the path better
+                * remains intact here.
+                */
+#  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 */
 
-       /* remove hostkey from the child's memory */
-       destroy_sensitive_data();
+               snprintf(buf, sizeof buf, "%.200s/%.50s",
+                        _PATH_MAILDIR, pw->pw_name);
+               child_set_env(&env, &envsize, "MAIL", buf);
 
-       /* login(1) is only called if we execute the login shell */
-       if (options.use_login && command != NULL)
-               options.use_login = 0;
+               /* Normal systems set SHELL by default. */
+               child_set_env(&env, &envsize, "SHELL", shell);
+       }
+       if (getenv("TZ"))
+               child_set_env(&env, &envsize, "TZ", getenv("TZ"));
 
-#if !defined(USE_PAM) && !defined(HAVE_OSF_SIA)
+       /* Set custom environment options from RSA authentication. */
        if (!options.use_login) {
-# ifdef HAVE_LOGIN_CAP
-               if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
-                       f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
-                           _PATH_NOLOGIN), "r");
-# else /* HAVE_LOGIN_CAP */
-               if (pw->pw_uid)
-                       f = fopen(_PATH_NOLOGIN, "r");
-# endif /* HAVE_LOGIN_CAP */
-               if (f) {
-                       /* /etc/nologin exists.  Print its contents and exit. */
-                       while (fgets(buf, sizeof(buf), f))
-                               fputs(buf, stderr);
-                       fclose(f);
-                       exit(254);
+               while (custom_environment) {
+                       struct envstring *ce = custom_environment;
+                       char *str = ce->s;
+
+                       for (i = 0; str[i] != '=' && str[i]; i++)
+                               ;
+                       if (str[i] == '=') {
+                               str[i] = 0;
+                               child_set_env(&env, &envsize, str, str + i + 1);
+                       }
+                       custom_environment = ce->next;
+                       xfree(ce->s);
+                       xfree(ce);
                }
        }
-#endif /* USE_PAM || HAVE_OSF_SIA */
-
-       /* Set login name, uid, gid, and groups. */
-       /* Login(1) does this as well, and it needs uid 0 for the "-h"
-          switch, so we let login(1) to this for us. */
-       if (!options.use_login) {
-#ifdef HAVE_OSF_SIA
-               session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
-               if (!check_quietlogin(s, command))
-                       do_motd();
-#else /* HAVE_OSF_SIA */
-#ifdef HAVE_CYGWIN
-               if (is_winnt) {
-#else
-               if (getuid() == 0 || geteuid() == 0) {
-#endif
-# ifdef HAVE_GETUSERATTR
-                       set_limits_from_userattr(pw->pw_name);
-# endif /* HAVE_GETUSERATTR */
-# ifdef HAVE_LOGIN_CAP
-                       if (setusercontext(lc, pw, pw->pw_uid,
-                           (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
-                               perror("unable to set user context");
-                               exit(1);
-                       }
-# else /* HAVE_LOGIN_CAP */
-#if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
-                       /* Sets login uid for accounting */
-                       if (getluid() == -1 && setluid(pw->pw_uid) == -1)
-                               error("setluid: %s", strerror(errno));
-#endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
-
-                       if (setlogin(pw->pw_name) < 0)
-                               error("setlogin failed: %s", strerror(errno));
-                       if (setgid(pw->pw_gid) < 0) {
-                               perror("setgid");
-                               exit(1);
-                       }
-                       /* Initialize the group list. */
-                       if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
-                               perror("initgroups");
-                               exit(1);
-                       }
-                       endgrent();
-#  ifdef USE_PAM
-                       /*
-                        * 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);
-#  endif /* USE_PAM */
-#  ifdef WITH_IRIX_JOBS
-                       jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
-                       if (jid == -1) {
-                               fatal("Failed to create job container: %.100s",
-                                     strerror(errno));
-                       }
-#  endif /* WITH_IRIX_JOBS */
-#  ifdef WITH_IRIX_ARRAY
-                       /* initialize array session */
-                       if (jid == 0) {
-                               if (newarraysess() != 0)
-                                       fatal("Failed to set up new array session: %.100s",
-                                             strerror(errno));
-                       }
-#  endif /* WITH_IRIX_ARRAY */
-#  ifdef WITH_IRIX_PROJECT
-                       /* initialize irix project info */
-                       if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
-                         debug("Failed to get project id, using projid 0");
-                         projid = 0;
-                       }
-                       if (setprid(projid))
-                         fatal("Failed to initialize project %d for %s: %.100s",
-                               (int)projid, pw->pw_name, strerror(errno));
-#  endif /* WITH_IRIX_PROJECT */
-#ifdef WITH_IRIX_AUDIT
-                       if (sysconf(_SC_AUDIT)) {
-                               debug("Setting sat id to %d", (int) pw->pw_uid);
-                               if (satsetid(pw->pw_uid))
-                                       debug("error setting satid: %.100s", strerror(errno));
-                       }
-#endif /* WITH_IRIX_AUDIT */
-
-#ifdef _AIX
-                       /*
-                        * AIX has a "usrinfo" area where logname and
-                        * other stuff is stored - a few applications
-                        * actually use this and die if it's not set
-                        */
-                       if (s->ttyfd == -1)
-                               s->tty[0] = '\0';
-                       cp = xmalloc(22 + strlen(s->tty) + 
-                           2 * strlen(pw->pw_name));
-                       i = sprintf(cp, "LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
-                           pw->pw_name, 0, pw->pw_name, 0, s->tty, 0, 0);
-                       if (usrinfo(SETUINFO, cp, i) == -1)
-                               fatal("Couldn't set usrinfo: %s", 
-                                   strerror(errno));
-                       debug3("AIX/UsrInfo: set len %d", i);
-                       xfree(cp);
-#endif
-
-                       /* Permanently switch to the desired uid. */
-                       permanently_set_uid(pw);
-# endif /* HAVE_LOGIN_CAP */
-               }
-#endif /* HAVE_OSF_SIA */
-
-#ifdef HAVE_CYGWIN
-               if (is_winnt)
-#endif
-               if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
-                       fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
-       }
-       /*
-        * 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;
-#ifdef HAVE_LOGIN_CAP
-       shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
-#endif
-
-#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 */
-
-       /* Initialize the environment. */
-       envsize = 100;
-       env = xmalloc(envsize * sizeof(char *));
-       env[0] = NULL;
-
-#ifdef HAVE_CYGWIN
-       /*
-        * The Windows environment contains some setting which are
-        * important for a running system. They must not be dropped.
-        */
-       copy_environment(&env, &envsize);
-#endif
-
-       if (!options.use_login) {
-               /* Set basic environment. */
-               child_set_env(&env, &envsize, "USER", pw->pw_name);
-               child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
-               child_set_env(&env, &envsize, "HOME", pw->pw_dir);
-#ifdef HAVE_LOGIN_CAP
-               (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
-               child_set_env(&env, &envsize, "PATH", getenv("PATH"));
-#else /* HAVE_LOGIN_CAP */
-# ifndef HAVE_CYGWIN
-               /*
-                * There's no standard path on Windows. The path contains
-                * important components pointing to the system directories,
-                * needed for loading shared libraries. So the path better
-                * remains intact here.
-                */
-               child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
-# endif /* HAVE_CYGWIN */
-#endif /* HAVE_LOGIN_CAP */
-
-               snprintf(buf, sizeof buf, "%.200s/%.50s",
-                        _PATH_MAILDIR, pw->pw_name);
-               child_set_env(&env, &envsize, "MAIL", buf);
-
-               /* Normal systems set SHELL by default. */
-               child_set_env(&env, &envsize, "SHELL", shell);
-       }
-       if (getenv("TZ"))
-               child_set_env(&env, &envsize, "TZ", getenv("TZ"));
-
-       /* Set custom environment options from RSA authentication. */
-       while (custom_environment) {
-               struct envstring *ce = custom_environment;
-               char *s = ce->s;
-               int i;
-               for (i = 0; s[i] != '=' && s[i]; i++);
-               if (s[i] == '=') {
-                       s[i] = 0;
-                       child_set_env(&env, &envsize, s, s + i + 1);
-               }
-               custom_environment = ce->next;
-               xfree(ce->s);
-               xfree(ce);
-       }
 
+       /* SSH_CLIENT deprecated */
        snprintf(buf, sizeof buf, "%.50s %d %d",
-                get_remote_ipaddr(), get_remote_port(), get_local_port());
+           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(), laddr, get_local_port());
+       xfree(laddr);
+       child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
+
        if (s->ttyfd != -1)
                child_set_env(&env, &envsize, "SSH_TTY", s->tty);
        if (s->term)
@@ -1214,36 +1091,63 @@ do_child(Session *s, const char *command)
                child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
                    original_command);
 
-#ifdef _AIX
-       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 _UNICOS
+       if (cray_tmpdir[0] != '\0')
+               child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
+#endif /* _UNICOS */
 
-#ifdef KRB4
+       /*
+        * 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.
+        */
        {
-               extern char *ticket;
+               char *cp;
 
-               if (ticket)
-                       child_set_env(&env, &envsize, "KRBTKFILE", ticket);
+               if ((cp = getenv("KRB5CCNAME")) != NULL)
+                       child_set_env(&env, &envsize, "KRB5CCNAME", cp);
        }
-#endif /* KRB4 */
 
+#ifdef _AIX
+       {
+               char *cp;
+
+               if ((cp = getenv("AUTHSTATE")) != NULL)
+                       child_set_env(&env, &envsize, "AUTHSTATE", cp);
+               read_environment_file(&env, &envsize, "/etc/environment");
+       }
+#endif
+#ifdef KRB5
+       if (s->authctxt->krb5_ccname)
+               child_set_env(&env, &envsize, "KRB5CCNAME",
+                   s->authctxt->krb5_ccname);
+#endif
 #ifdef USE_PAM
-       /* Pull in any environment variables that may have been set by PAM. */
-       do_pam_environment(&env, &envsize);
+       /*
+        * 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);
+       }
 #endif /* USE_PAM */
 
-       if (auth_get_socket_name() != NULL)
+       if (auth_sock_name != NULL)
                child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
-                             auth_get_socket_name());
+                   auth_sock_name);
 
        /* read $HOME/.ssh/environment. */
-       if (!options.use_login) {
+       if (options.permit_user_env && !options.use_login) {
                snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
-                   pw->pw_dir);
+                   strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
                read_environment_file(&env, &envsize, buf);
        }
        if (debug_flag) {
@@ -1252,17 +1156,249 @@ do_child(Session *s, const char *command)
                for (i = 0; env[i]; i++)
                        fprintf(stderr, "  %.200s\n", env[i]);
        }
-       /* we have to stash the hostname before we close our socket. */
-       if (options.use_login)
-               hostname = get_remote_name_or_ip(utmp_len,
-                   options.reverse_mapping_check);
-       /*
-        * Close the connection descriptors; note that this is the child, and
-        * the server will still have the socket open, and it is important
-        * that we do not shutdown it.  Note that the descriptors cannot be
-        * closed before building the environment, as we call
-        * get_remote_ipaddr there.
-        */
+       return env;
+}
+
+/*
+ * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
+ * first in this order).
+ */
+static void
+do_rc_files(Session *s, const char *shell)
+{
+       FILE *f = NULL;
+       char cmd[1024];
+       int do_xauth;
+       struct stat st;
+
+       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)) {
+               snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
+                   shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
+               if (debug_flag)
+                       fprintf(stderr, "Running %s\n", cmd);
+               f = popen(cmd, "w");
+               if (f) {
+                       if (do_xauth)
+                               fprintf(f, "%s %s\n", s->auth_proto,
+                                   s->auth_data);
+                       pclose(f);
+               } else
+                       fprintf(stderr, "Could not run %s\n",
+                           _PATH_SSH_USER_RC);
+       } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
+               if (debug_flag)
+                       fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
+                           _PATH_SSH_SYSTEM_RC);
+               f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
+               if (f) {
+                       if (do_xauth)
+                               fprintf(f, "%s %s\n", s->auth_proto,
+                                   s->auth_data);
+                       pclose(f);
+               } else
+                       fprintf(stderr, "Could not run %s\n",
+                           _PATH_SSH_SYSTEM_RC);
+       } else if (do_xauth && options.xauth_location != NULL) {
+               /* Add authority data to .Xauthority if appropriate. */
+               if (debug_flag) {
+                       fprintf(stderr,
+                           "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);
+               }
+               snprintf(cmd, sizeof cmd, "%s -q -",
+                   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);
+                       pclose(f);
+               } else {
+                       fprintf(stderr, "Could not run %s\n",
+                           cmd);
+               }
+       }
+}
+
+static void
+do_nologin(struct passwd *pw)
+{
+       FILE *f = NULL;
+       char buf[1024];
+
+#ifdef HAVE_LOGIN_CAP
+       if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
+               f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
+                   _PATH_NOLOGIN), "r");
+#else
+       if (pw->pw_uid)
+               f = fopen(_PATH_NOLOGIN, "r");
+#endif
+       if (f) {
+               /* /etc/nologin exists.  Print its contents and exit. */
+               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);
+       }
+}
+
+/* Set login name, uid, gid, and groups. */
+void
+do_setusercontext(struct passwd *pw)
+{
+#ifndef HAVE_CYGWIN
+       if (getuid() == 0 || geteuid() == 0)
+#endif /* HAVE_CYGWIN */
+       {
+
+#ifdef HAVE_SETPCRED
+               if (setpcred(pw->pw_name, (char **)NULL) == -1)
+                       fatal("Failed to set process credentials");
+#endif /* HAVE_SETPCRED */
+#ifdef HAVE_LOGIN_CAP
+# ifdef __bsdi__
+               setpgid(0, 0);
+# endif
+#ifdef GSSAPI
+               if (options.gss_authentication) {
+                       temporarily_use_uid(pw);
+                       ssh_gssapi_storecreds();
+                       restore_uid();
+               }
+#endif
+# ifdef USE_PAM
+               if (options.use_pam) {
+                       do_pam_session();
+                       do_pam_setcred(0);
+               }
+# endif /* USE_PAM */
+               if (setusercontext(lc, pw, pw->pw_uid,
+                   (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
+                       perror("unable to set user context");
+                       exit(1);
+               }
+#else
+# if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
+               /* Sets login uid for accounting */
+               if (getluid() == -1 && setluid(pw->pw_uid) == -1)
+                       error("setluid: %s", strerror(errno));
+# endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
+
+               if (setlogin(pw->pw_name) < 0)
+                       error("setlogin failed: %s", strerror(errno));
+               if (setgid(pw->pw_gid) < 0) {
+                       perror("setgid");
+                       exit(1);
+               }
+               /* Initialize the group list. */
+               if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
+                       perror("initgroups");
+                       exit(1);
+               }
+               endgrent();
+#ifdef GSSAPI
+               if (options.gss_authentication) {
+                       temporarily_use_uid(pw);
+                       ssh_gssapi_storecreds();
+                       restore_uid();
+               }
+#endif
+# ifdef USE_PAM
+               /*
+                * PAM credentials may take the form of supplementary groups.
+                * These will have been wiped by the above initgroups() call.
+                * Reestablish them here.
+                */
+               if (options.use_pam) {
+                       do_pam_session();
+                       do_pam_setcred(0);
+               }
+# 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) */
+# ifdef _AIX
+               aix_usrinfo(pw);
+# endif /* _AIX */
+#if defined(HAVE_LIBIAF)  &&  !defined(BROKEN_LIBIAF)
+               if (set_id(pw->pw_name) != 0) {
+                       exit(1);
+               }
+#endif /* HAVE_LIBIAF  && !BROKEN_LIBIAF */
+               /* Permanently switch to the desired uid. */
+               permanently_set_uid(pw);
+#endif
+       }
+
+#ifdef HAVE_CYGWIN
+       if (is_winnt)
+#endif
+       if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
+               fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
+}
+
+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
+launch_login(struct passwd *pw, const char *hostname)
+{
+       /* Launch login(1). */
+
+       execl(LOGIN_PROGRAM, "login", "-h", hostname,
+#ifdef xxxLOGIN_NEEDS_TERM
+                   (s->term ? s->term : "unknown"),
+#endif /* LOGIN_NEEDS_TERM */
+#ifdef LOGIN_NO_ENDOPT
+           "-p", "-f", pw->pw_name, (char *)NULL);
+#else
+           "-p", "-f", "--", pw->pw_name, (char *)NULL);
+#endif
+
+       /* Login couldn't be executed, die. */
+
+       perror("login");
+       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 {
@@ -1290,164 +1426,191 @@ do_child(Session *s, const char *command)
         */
        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.
+ */
+void
+do_child(Session *s, const char *command)
+{
+       extern char **environ;
+       char **env;
+       char *argv[10];
+       const char *shell, *shell0, *hostname = NULL;
+       struct passwd *pw = s->pw;
+
+       /* 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;
+
+#ifdef _UNICOS
+       cray_setup(pw->pw_uid, pw->pw_name, command);
+#endif /* _UNICOS */
+
+       /*
+        * Login(1) does this as well, and it needs uid 0 for the "-h"
+        * switch, so we let login(1) to this for us.
+        */
+       if (!options.use_login) {
+#ifdef HAVE_OSF_SIA
+               session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
+               if (!check_quietlogin(s, command))
+                       do_motd();
+#else /* HAVE_OSF_SIA */
+               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);
 
-       /* 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));
 #ifdef HAVE_LOGIN_CAP
-               if (login_getcapbool(lc, "requirehome", 0))
-                       exit(1);
+       shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
 #endif
-       }
 
+       /* we have to stash the hostname before we close our socket. */
+       if (options.use_login)
+               hostname = get_remote_name_or_ip(utmp_len,
+                   options.use_dns);
        /*
-        * Must take new environment into use so that .ssh/rc, /etc/sshrc and
-        * xauth are run in the proper environment.
+        * Close the connection descriptors; note that this is the child, and
+        * the server will still have the socket open, and it is important
+        * that we do not shutdown it.  Note that the descriptors cannot be
+        * closed before building the environment, as we call
+        * get_remote_ipaddr there.
+        */
+       child_close_fds();
+
+       /*
+        * Must take new environment into use so that .ssh/rc,
+        * /etc/ssh/sshrc and xauth are run in the proper environment.
         */
        environ = env;
 
+#if defined(KRB5) && defined(USE_AFS)
        /*
-        * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
-        * in this order).
+        * 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.
         */
-       if (!options.use_login) {
-               /* ignore _PATH_SSH_USER_RC for subsystems */
-               if (!s->is_subsystem && (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)
-                               fprintf(stderr, "Running %s\n", cmd);
-                       f = popen(cmd, "w");
-                       if (f) {
-                               if (do_xauth)
-                                       fprintf(f, "%s %s\n", s->auth_proto,
-                                           s->auth_data);
-                               pclose(f);
-                       } else
-                               fprintf(stderr, "Could not run %s\n",
-                                   _PATH_SSH_USER_RC);
-               } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
-                       if (debug_flag)
-                               fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
-                                   _PATH_SSH_SYSTEM_RC);
-                       f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
-                       if (f) {
-                               if (do_xauth)
-                                       fprintf(f, "%s %s\n", s->auth_proto,
-                                           s->auth_data);
-                               pclose(f);
-                       } else
-                               fprintf(stderr, "Could not run %s\n",
-                                   _PATH_SSH_SYSTEM_RC);
-               } else if (do_xauth && options.xauth_location != NULL) {
-                       /* Add authority data to .Xauthority if appropriate. */
-                       char *screen = strchr(s->display, ':');
-
-                       if (debug_flag) {
-                               fprintf(stderr,
-                                   "Running %.100s add "
-                                   "%.100s %.100s %.100s\n",
-                                   options.xauth_location, s->display,
-                                   s->auth_proto, s->auth_data);
-                               if (screen != NULL)
-                                       fprintf(stderr,
-                                           "Adding %.*s/unix%s %s %s\n",
-                                           (int)(screen - s->display),
-                                           s->display, screen,
-                                           s->auth_proto, s->auth_data);
-                       }
-                       snprintf(cmd, sizeof cmd, "%s -q -",
-                           options.xauth_location);
-                       f = popen(cmd, "w");
-                       if (f) {
-                               fprintf(f, "add %s %s %s\n", s->display,
-                                   s->auth_proto, s->auth_data);
-                               if (screen != NULL)
-                                       fprintf(f, "add %.*s/unix%s %s %s\n",
-                                           (int)(screen - s->display),
-                                           s->display, screen,
-                                           s->auth_proto,
-                                           s->auth_data);
-                               pclose(f);
-                       } else {
-                               fprintf(stderr, "Could not run %s\n",
-                                   cmd);
-                       }
-               }
-               /* Get the last component of the shell name. */
-               cp = strrchr(shell, '/');
-               if (cp)
-                       cp++;
-               else
-                       cp = shell;
+
+       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
+
+       /* 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));
+#ifdef HAVE_LOGIN_CAP
+               if (login_getcapbool(lc, "requirehome", 0))
+                       exit(1);
+#endif
        }
 
+       if (!options.use_login)
+               do_rc_files(s, shell);
+
        /* restore SIGPIPE for child */
        signal(SIGPIPE,  SIG_DFL);
 
+       if (options.use_login) {
+               launch_login(pw, hostname);
+               /* NEVERREACHED */
+       }
+
+       /* Get the last component of the shell name. */
+       if ((shell0 = strrchr(shell, '/')) != NULL)
+               shell0++;
+       else
+               shell0 = shell;
+
        /*
         * If we have no command, execute the shell.  In this case, the shell
         * name to be passed in argv[0] is preceded by '-' to indicate that
         * this is a login shell.
         */
        if (!command) {
-               if (!options.use_login) {
-                       char buf[256];
+               char argv0[256];
 
-                       /*
-                        * Check for mail if we have a tty and it was enabled
-                        * in server options.
-                        */
-                       if (s->ttyfd != -1 && options.check_mail) {
-                               char *mailbox;
-                               struct stat mailstat;
-
-                               mailbox = getenv("MAIL");
-                               if (mailbox != NULL) {
-                                       if (stat(mailbox, &mailstat) != 0 ||
-                                           mailstat.st_size == 0)
-                                               printf("No mail.\n");
-                                       else if (mailstat.st_mtime < mailstat.st_atime)
-                                               printf("You have mail.\n");
-                                       else
-                                               printf("You have new mail.\n");
-                               }
-                       }
-                       /* Start the shell.  Set initial character to '-'. */
-                       buf[0] = '-';
-                       strncpy(buf + 1, cp, sizeof(buf) - 1);
-                       buf[sizeof(buf) - 1] = 0;
-
-                       /* Execute the shell. */
-                       argv[0] = buf;
-                       argv[1] = NULL;
-                       execve(shell, argv, env);
+               /* Start the shell.  Set initial character to '-'. */
+               argv0[0] = '-';
 
-                       /* Executing the shell failed. */
+               if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
+                   >= sizeof(argv0) - 1) {
+                       errno = EINVAL;
                        perror(shell);
                        exit(1);
+               }
 
-               } else {
-                       /* Launch login(1). */
-
-                       execl(LOGIN_PROGRAM, "login", "-h", hostname,
-#ifdef LOGIN_NEEDS_TERM
-                            s->term? s->term : "unknown",
-#endif
-                            "-p", "-f", "--", pw->pw_name, NULL);
-
-                       /* Login couldn't be executed, die. */
+               /* Execute the shell. */
+               argv[0] = argv0;
+               argv[1] = NULL;
+               execve(shell, argv, env);
 
-                       perror("login");
-                       exit(1);
-               }
+               /* Executing the shell failed. */
+               perror(shell);
+               exit(1);
        }
        /*
         * Execute the command using the user's shell.  This uses the -c
         * option to execute the command.
         */
-       argv[0] = (char *) cp;
+       argv[0] = (char *) shell0;
        argv[1] = "-c";
        argv[2] = (char *) command;
        argv[3] = NULL;
@@ -1463,12 +1626,12 @@ session_new(void)
        static int did_init = 0;
        if (!did_init) {
                debug("session_new: init");
-               for(i = 0; i < MAX_SESSIONS; i++) {
+               for (i = 0; i < MAX_SESSIONS; i++) {
                        sessions[i].used = 0;
                }
                did_init = 1;
        }
-       for(i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < MAX_SESSIONS; i++) {
                Session *s = &sessions[i];
                if (! s->used) {
                        memset(s, 0, sizeof(*s));
@@ -1477,6 +1640,7 @@ session_new(void)
                        s->ttyfd = -1;
                        s->used = 1;
                        s->self = i;
+                       s->x11_chanids = NULL;
                        debug("session_new: session %d", i);
                        return s;
                }
@@ -1488,19 +1652,19 @@ static void
 session_dump(void)
 {
        int i;
-       for(i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < MAX_SESSIONS; i++) {
                Session *s = &sessions[i];
-               debug("dump: used %d session %d %p channel %d pid %d",
+               debug("dump: used %d session %d %p channel %d pid %ld",
                    s->used,
                    s->self,
                    s,
                    s->chanid,
-                   s->pid);
+                   (long)s->pid);
        }
 }
 
 int
-session_open(int chanid)
+session_open(Authctxt *authctxt, int chanid)
 {
        Session *s = session_new();
        debug("session_open: channel %d", chanid);
@@ -1508,19 +1672,36 @@ session_open(int chanid)
                error("no more sessions");
                return 0;
        }
-       s->pw = auth_get_user();
-       if (s->pw == NULL)
+       s->authctxt = authctxt;
+       s->pw = authctxt->pw;
+       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;
        return 1;
 }
 
+Session *
+session_by_tty(char *tty)
+{
+       int i;
+       for (i = 0; i < MAX_SESSIONS; 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);
+                       return s;
+               }
+       }
+       debug("session_by_tty: unknown tty %.100s", tty);
+       session_dump();
+       return NULL;
+}
+
 static Session *
 session_by_channel(int id)
 {
        int i;
-       for(i = 0; i < MAX_SESSIONS; i++) {
+       for (i = 0; i < MAX_SESSIONS; i++) {
                Session *s = &sessions[i];
                if (s->used && s->chanid == id) {
                        debug("session_by_channel: session %d channel %d", i, id);
@@ -1532,17 +1713,40 @@ session_by_channel(int id)
        return NULL;
 }
 
+static Session *
+session_by_x11_channel(int id)
+{
+       int i, j;
+
+       for (i = 0; i < MAX_SESSIONS; 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 %d", pid);
-       for(i = 0; i < MAX_SESSIONS; i++) {
+       debug("session_by_pid: pid %ld", (long)pid);
+       for (i = 0; i < MAX_SESSIONS; i++) {
                Session *s = &sessions[i];
                if (s->used && s->pid == pid)
                        return s;
        }
-       error("session_by_pid: unknown pid %d", pid);
+       error("session_by_pid: unknown pid %ld", (long)pid);
        session_dump();
        return NULL;
 }
@@ -1554,7 +1758,7 @@ session_window_change_req(Session *s)
        s->row = packet_get_int();
        s->xpixel = packet_get_int();
        s->ypixel = packet_get_int();
-       packet_done();
+       packet_check_eom();
        pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
        return 1;
 }
@@ -1593,7 +1797,7 @@ session_pty_req(Session *s)
 
        /* Allocate a pty and open it. */
        debug("Allocating pty.");
-       if (!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;
@@ -1609,17 +1813,13 @@ 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);
-       pty_setowner(s->pw, s->tty);
+       if (!use_privsep)
+               pty_setowner(s->pw, s->tty);
 
        /* Set window size from the packet. */
        pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
 
-       packet_done();
+       packet_check_eom();
        session_proctitle(s);
        return 1;
 }
@@ -1627,25 +1827,34 @@ session_pty_req(Session *s)
 static int
 session_subsystem_req(Session *s)
 {
+       struct stat st;
        u_int len;
        int success = 0;
-       char *subsys = packet_get_string(&len);
-       int i;
+       char *cmd, *subsys = packet_get_string(&len);
+       u_int i;
 
-       packet_done();
-       log("subsystem request for %s", subsys);
+       packet_check_eom();
+       logit("subsystem request for %.100s", subsys);
 
        for (i = 0; i < options.num_subsystems; i++) {
-               if(strcmp(subsys, options.subsystem_name[i]) == 0) {
-                       debug("subsystem: exec() %s", options.subsystem_command[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,
+                                   strerror(errno));
+                               break;
+                       }
+                       debug("subsystem: exec() %s", cmd);
                        s->is_subsystem = 1;
-                       do_exec_no_pty(s, options.subsystem_command[i]);
+                       do_exec(s, cmd);
                        success = 1;
+                       break;
                }
        }
 
        if (!success)
-               log("subsystem request for %s failed, subsystem not found", subsys);
+               logit("subsystem request for %.100s failed, subsystem not found",
+                   subsys);
 
        xfree(subsys);
        return success;
@@ -1656,11 +1865,16 @@ session_x11_req(Session *s)
 {
        int success;
 
+       if (s->auth_proto != NULL || s->auth_data != NULL) {
+               error("session_x11_req: session %d: "
+                   "x11 fowarding 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);
        s->screen = packet_get_int();
-       packet_done();
+       packet_check_eom();
 
        success = session_setup_x11fwd(s);
        if (!success) {
@@ -1675,7 +1889,7 @@ session_x11_req(Session *s)
 static int
 session_shell_req(Session *s)
 {
-       packet_done();
+       packet_check_eom();
        do_exec(s, NULL);
        return 1;
 }
@@ -1685,17 +1899,65 @@ session_exec_req(Session *s)
 {
        u_int len;
        char *command = packet_get_string(&len);
-       packet_done();
+       packet_check_eom();
        do_exec(s, command);
        xfree(command);
        return 1;
 }
 
+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, sizeof(*s->env) *
+                           (s->num_env + 1));
+                       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_done();
+       packet_check_eom();
        if (no_agent_forwarding_flag) {
                debug("session_auth_agent_req: no_agent_forwarding_flag");
                return 0;
@@ -1708,28 +1970,18 @@ session_auth_agent_req(Session *s)
        }
 }
 
-void
-session_input_channel_req(int id, void *arg)
+int
+session_input_channel_req(Channel *c, const char *rtype)
 {
-       u_int len;
-       int reply;
        int success = 0;
-       char *rtype;
        Session *s;
-       Channel *c;
-
-       rtype = packet_get_string(&len);
-       reply = packet_get_char();
 
-       s = session_by_channel(id);
-       if (s == NULL)
-               fatal("session_input_channel_req: channel %d: no session", id);
-       c = channel_lookup(id);
-       if (c == NULL)
-               fatal("session_input_channel_req: channel %d: bad channel", id);
-
-       debug("session_input_channel_req: session %d channel %d request %s reply %d",
-           s->self, id, rtype, reply);
+       if ((s = session_by_channel(c->self)) == NULL) {
+               logit("session_input_channel_req: no session %d req %.100s",
+                   c->self, rtype);
+               return 0;
+       }
+       debug("session_input_channel_req: session %d req %s", s->self, rtype);
 
        /*
         * a session is in LARVAL state until a shell, a command
@@ -1748,19 +2000,17 @@ session_input_channel_req(int id, void *arg)
                        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);
        }
 
-       if (reply) {
-               packet_start(success ?
-                   SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
-               packet_put_int(c->remote_id);
-               packet_send();
-       }
-       xfree(rtype);
+       return success;
 }
 
 void
@@ -1777,18 +2027,17 @@ session_set_fds(Session *s, int fdin, int fdout, int fderr)
        channel_set_fds(s->chanid,
            fdout, fdin, fderr,
            fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
-           1);
+           1,
+           CHAN_SES_WINDOW_DEFAULT);
 }
 
 /*
  * Function to perform pty cleanup. Also called if we get aborted abnormally
  * (e.g., due to a dropped connection).
  */
-static void
-session_pty_cleanup(void *session)
+void
+session_pty_cleanup2(Session *s)
 {
-       Session *s = session;
-
        if (s == NULL) {
                error("session_pty_cleanup: no session");
                return;
@@ -1800,10 +2049,11 @@ session_pty_cleanup(void *session)
 
        /* Record that the user has logged out. */
        if (s->pid != 0)
-               record_logout(s->pid, s->tty);
+               record_logout(s->pid, s->tty, s->pw->pw_name);
 
        /* Release the pseudo-tty. */
-       pty_release(s->tty);
+       if (getuid() == 0)
+               pty_release(s->tty);
 
        /*
         * Close the server side of the socket pairs.  We must do this after
@@ -1811,31 +2061,114 @@ session_pty_cleanup(void *session)
         * while we're still cleaning up.
         */
        if (close(s->ptymaster) < 0)
-               error("close(s->ptymaster): %s", strerror(errno));
+               error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
+
+       /* unlink pty from session */
+       s->ttyfd = -1;
+}
+
+void
+session_pty_cleanup(Session *s)
+{
+       PRIVSEP(session_pty_cleanup2(s));
+}
+
+static char *
+sig2name(int sig)
+{
+#define SSH_SIG(x) if (sig == SIG ## x) return #x
+       SSH_SIG(ABRT);
+       SSH_SIG(ALRM);
+       SSH_SIG(FPE);
+       SSH_SIG(HUP);
+       SSH_SIG(ILL);
+       SSH_SIG(INT);
+       SSH_SIG(KILL);
+       SSH_SIG(PIPE);
+       SSH_SIG(QUIT);
+       SSH_SIG(SEGV);
+       SSH_SIG(TERM);
+       SSH_SIG(USR1);
+       SSH_SIG(USR2);
+#undef SSH_SIG
+       return "SIG@openssh.com";
+}
+
+static void
+session_close_x11(int id)
+{
+       Channel *c;
+
+       if ((c = channel_lookup(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)
 {
        Channel *c;
-       if (s == NULL)
-               fatal("session_close: no session");
-       c = channel_lookup(s->chanid);
-       if (c == NULL)
+       u_int i;
+
+       if ((c = channel_lookup(s->chanid)) == NULL)
                fatal("session_exit_message: session %d: no channel %d",
                    s->self, s->chanid);
-       debug("session_exit_message: session %d channel %d pid %d",
-           s->self, s->chanid, s->pid);
+       debug("session_exit_message: session %d channel %d pid %ld",
+           s->self, s->chanid, (long)s->pid);
 
        if (WIFEXITED(status)) {
-               channel_request_start(s->chanid,
-                   "exit-status", 0);
+               channel_request_start(s->chanid, "exit-status", 0);
                packet_put_int(WEXITSTATUS(status));
                packet_send();
        } else if (WIFSIGNALED(status)) {
-               channel_request_start(s->chanid,
-                   "exit-signal", 0);
-               packet_put_int(WTERMSIG(status));
+               channel_request_start(s->chanid, "exit-signal", 0);
+               packet_put_cstring(sig2name(WTERMSIG(status)));
 #ifdef WCOREDUMP
                packet_put_char(WCOREDUMP(status));
 #else /* WCOREDUMP */
@@ -1861,25 +2194,43 @@ session_exit_message(Session *s, int status)
        if (c->ostate != CHAN_OUTPUT_CLOSED)
                chan_write_failed(c);
        s->chanid = -1;
+
+       /* 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;
+               }
+       }
 }
 
-static void
+void
 session_close(Session *s)
 {
-       debug("session_close: session %d pid %d", s->self, s->pid);
-       if (s->ttyfd != -1) {
-               fatal_remove_cleanup(session_pty_cleanup, (void *)s);
+       u_int i;
+
+       debug("session_close: session %d pid %ld", s->self, (long)s->pid);
+       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;
+       for (i = 0; i < s->num_env; i++) {
+               xfree(s->env[i].name);
+               xfree(s->env[i].val);
+       }
+       if (s->env != NULL)
+               xfree(s->env);
        session_proctitle(s);
 }
 
@@ -1888,7 +2239,8 @@ session_close_by_pid(pid_t pid, int status)
 {
        Session *s = session_by_pid(pid);
        if (s == NULL) {
-               debug("session_close_by_pid: no session for pid %d", pid);
+               debug("session_close_by_pid: no session for pid %ld",
+                   (long)pid);
                return;
        }
        if (s->chanid != -1)
@@ -1904,23 +2256,41 @@ void
 session_close_by_channel(int id, void *arg)
 {
        Session *s = session_by_channel(id);
+
        if (s == NULL) {
-               debug("session_close_by_channel: no session for channel %d", id);
+               debug("session_close_by_channel: no session for id %d", id);
                return;
        }
-       /* disconnect channel */
+       debug("session_close_by_channel: channel %d child %ld",
+           id, (long)s->pid);
+       if (s->pid != 0) {
+               debug("session_close_by_channel: channel %d: has child", id);
+               /*
+                * delay detach of session, but release pty, since
+                * the fd's to the child are already closed
+                */
+               if (s->ttyfd != -1)
+                       session_pty_cleanup(s);
+               return;
+       }
+       /* detach by removing callback */
        channel_cancel_cleanup(s->chanid);
        s->chanid = -1;
+       session_close(s);
+}
 
-       debug("session_close_by_channel: channel %d kill %d", id, s->pid);
-       if (s->pid == 0) {
-               /* close session immediately */
-               session_close(s);
-       } else {
-               /* notify child, delay session cleanup */
-               if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
-                       error("session_close_by_channel: kill %d: %s",
-                           s->pid, strerror(errno));
+void
+session_destroy_all(void (*closefunc)(Session *))
+{
+       int i;
+       for (i = 0; i < MAX_SESSIONS; i++) {
+               Session *s = &sessions[i];
+               if (s->used) {
+                       if (closefunc != NULL)
+                               closefunc(s);
+                       else
+                               session_close(s);
+               }
        }
 }
 
@@ -1929,13 +2299,22 @@ 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 < MAX_SESSIONS; 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')
@@ -1956,6 +2335,9 @@ int
 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.");
@@ -1979,16 +2361,106 @@ session_setup_x11fwd(Session *s)
                debug("X11 display already set.");
                return 0;
        }
-       s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
-       if (s->display == NULL) {
+       if (x11_create_display_inet(options.x11_display_offset,
+           options.x11_use_localhost, s->single_connection,
+           &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);
+       }
+
+       /* Set up a suitable value for the DISPLAY variable. */
+       if (gethostname(hostname, sizeof(hostname)) < 0)
+               fatal("gethostname: %.100s", strerror(errno));
+       /*
+        * auth_display must be used as the displayname when the
+        * authorization entry is added with xauth(1).  This will be
+        * different than the DISPLAY string for localhost displays.
+        */
+       if (options.x11_use_localhost) {
+               snprintf(display, sizeof display, "localhost:%u.%u",
+                   s->display_number, s->screen);
+               snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
+                   s->display_number, s->screen);
+               s->display = xstrdup(display);
+               s->auth_display = xstrdup(auth_display);
+       } else {
+#ifdef IPADDR_IN_DISPLAY
+               struct hostent *he;
+               struct in_addr my_addr;
+
+               he = gethostbyname(hostname);
+               if (he == NULL) {
+                       error("Can't get IP address for X11 DISPLAY.");
+                       packet_send_debug("Can't get IP address for X11 DISPLAY.");
+                       return 0;
+               }
+               memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
+               snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
+                   s->display_number, s->screen);
+#else
+               snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
+                   s->display_number, s->screen);
+#endif
+               s->display = xstrdup(display);
+               s->auth_display = xstrdup(display);
+       }
+
        return 1;
 }
 
 static void
 do_authenticated2(Authctxt *authctxt)
 {
-       server_loop2();
+       server_loop2(authctxt);
+}
+
+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 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
+
+#ifdef USE_PAM
+       if (options.use_pam) {
+               sshpam_cleanup();
+               sshpam_thread_cleanup();
+       }
+#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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