X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/1c59025848be8ebfcd37d2ba3dbf73600643675d..cd744742c3efb60d9791f485ce57956223e4aaa0:/session.c diff --git a/session.c b/session.c index 7a064ad5..af2e7199 100644 --- a/session.c +++ b/session.c @@ -33,7 +33,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: session.c,v 1.159 2003/07/22 13:35:22 markus Exp $"); +RCSID("$OpenBSD: session.c,v 1.172 2004/01/30 09:48:57 markus Exp $"); #include "ssh.h" #include "ssh1.h" @@ -58,17 +58,19 @@ RCSID("$OpenBSD: session.c,v 1.159 2003/07/22 13:35:22 markus Exp $"); #include "session.h" #include "monitor_wrap.h" -#ifdef HAVE_CYGWIN -#include -#include -#define is_winnt (GetVersion() < 0x80000000) +#if defined(KRB5) && defined(USE_AFS) +#include +#endif + +#ifdef GSSAPI +#include "ssh-gss.h" #endif /* func */ Session *session_new(void); void session_set_fds(Session *, int, int, int); -void session_pty_cleanup(void *); +void session_pty_cleanup(Session *); void session_proctitle(Session *); int session_setup_x11fwd(Session *); void do_exec_pty(Session *, const char *); @@ -108,6 +110,8 @@ Session sessions[MAX_SESSIONS]; 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; @@ -115,10 +119,8 @@ static char *auth_sock_dir = NULL; /* removes the agent forwarding socket */ static void -auth_sock_cleanup_proc(void *_pw) +auth_sock_cleanup_proc(struct passwd *pw) { - struct passwd *pw = _pw; - if (auth_sock_name != NULL) { temporarily_use_uid(pw); unlink(auth_sock_name); @@ -146,7 +148,7 @@ auth_input_request_forwarding(struct passwd * pw) /* Allocate a buffer for the socket name, and format the name. */ auth_sock_name = xmalloc(MAXPATHLEN); auth_sock_dir = xmalloc(MAXPATHLEN); - strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); + strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); /* Create private directory for socket */ if (mkdtemp(auth_sock_dir) == NULL) { @@ -162,9 +164,6 @@ auth_input_request_forwarding(struct passwd * pw) snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld", auth_sock_dir, (long) getpid()); - /* delete agent socket on fatal() */ - fatal_add_cleanup(auth_sock_cleanup_proc, pw); - /* Create the socket. */ sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) @@ -182,7 +181,7 @@ auth_input_request_forwarding(struct passwd * pw) restore_uid(); /* Start listening on the socket. */ - if (listen(sock, 5) < 0) + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) packet_disconnect("listen: %.100s", strerror(errno)); /* Allocate a channel for the authentication agent socket. */ @@ -194,6 +193,15 @@ auth_input_request_forwarding(struct passwd * pw) return 1; } +static void +display_loginmsg(void) +{ + if (buffer_len(&loginmsg) > 0) { + buffer_append(&loginmsg, "\0", 1); + printf("%s\n", (char *)buffer_ptr(&loginmsg)); + buffer_clear(&loginmsg); + } +} void do_authenticated(Authctxt *authctxt) @@ -209,7 +217,6 @@ do_authenticated(Authctxt *authctxt) close(startup_pipe); startup_pipe = -1; } - /* setup the channel layer */ if (!no_port_forwarding_flag && options.allow_tcp_forwarding) channel_permit_all_opens(); @@ -219,13 +226,7 @@ do_authenticated(Authctxt *authctxt) else do_authenticated1(authctxt); - /* remove agent socket */ - if (auth_sock_name != NULL) - auth_sock_cleanup_proc(authctxt->pw); -#ifdef KRB5 - if (options.kerberos_ticket_cleanup) - krb5_cleanup_proc(authctxt); -#endif + do_cleanup(authctxt); } /* @@ -334,30 +335,6 @@ do_authenticated1(Authctxt *authctxt) success = 1; break; -#ifdef KRB5 - case SSH_CMSG_HAVE_KERBEROS_TGT: - if (!options.kerberos_tgt_passing) { - verbose("Kerberos TGT passing disabled."); - } else { - char *kdata = packet_get_string(&dlen); - packet_check_eom(); - - /* XXX - 0x41, used for AFS */ - if (kdata[0] != 0x41) { - krb5_data tgt; - tgt.data = kdata; - tgt.length = dlen; - - if (auth_krb5_tgt(s->authctxt, &tgt)) - success = 1; - else - verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user); - } - xfree(kdata); - } - break; -#endif - case SSH_CMSG_EXEC_SHELL: case SSH_CMSG_EXEC_CMD: if (type == SSH_CMSG_EXEC_CMD) { @@ -421,18 +398,13 @@ do_exec_no_pty(Session *s, const char *command) session_proctitle(s); #if defined(USE_PAM) - if (options.use_pam) { - do_pam_session(s->pw->pw_name, NULL); + if (options.use_pam && !use_privsep) do_pam_setcred(1); - if (is_pam_password_change_required()) - packet_disconnect("Password change required but no " - "TTY available"); - } #endif /* USE_PAM */ /* Fork the child. */ if ((pid = fork()) == 0) { - fatal_remove_all_cleanups(); + is_child = 1; /* Child. Reinitialize the log since the pid has changed. */ log_init(__progname, options.log_level, options.log_facility, log_stderr); @@ -551,14 +523,15 @@ do_exec_pty(Session *s, const char *command) #if defined(USE_PAM) if (options.use_pam) { - do_pam_session(s->pw->pw_name, s->tty); - do_pam_setcred(1); + do_pam_set_tty(s->tty); + if (!use_privsep) + do_pam_setcred(1); } #endif /* Fork the child. */ if ((pid = fork()) == 0) { - fatal_remove_all_cleanups(); + is_child = 1; /* Child. Reinitialize the log because the pid has changed. */ log_init(__progname, options.log_level, options.log_facility, log_stderr); @@ -654,7 +627,7 @@ do_pre_login(Session *s) if (getpeername(packet_get_connection_in(), (struct sockaddr *) & from, &fromlen) < 0) { debug("getpeername: %.100s", strerror(errno)); - fatal_cleanup(); + cleanup_exit(255); } } @@ -677,6 +650,14 @@ do_exec(Session *s, const char *command) debug("Forced command '%.900s'", command); } +#ifdef GSSAPI + if (options.gss_authentication) { + temporarily_use_uid(s->pw); + ssh_gssapi_storecreds(); + restore_uid(); + } +#endif + if (s->ttyfd != -1) do_exec_pty(s, command); else @@ -706,7 +687,7 @@ do_login(Session *s, const char *command) if (getpeername(packet_get_connection_in(), (struct sockaddr *) & from, &fromlen) < 0) { debug("getpeername: %.100s", strerror(errno)); - fatal_cleanup(); + cleanup_exit(255); } } @@ -722,26 +703,18 @@ do_login(Session *s, const char *command) * If password change is needed, do it now. * This needs to occur before the ~/.hushlogin check. */ - if (options.use_pam && 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 (options.use_pam && !is_pam_password_change_required()) - print_pam_messages(); -#endif /* USE_PAM */ - - /* display post-login message */ - if (buffer_len(&loginmsg) > 0) { - buffer_append(&loginmsg, "\0", 1); - printf("%s\n", (char *)buffer_ptr(&loginmsg)); - } - buffer_free(&loginmsg); + display_loginmsg(); #ifndef NO_SSH_LASTLOG if (options.print_lastlog && s->last_login_time != 0) { @@ -812,12 +785,23 @@ check_quietlogin(Session *s, const char *command) * Sets the value of the given variable in the environment. If the variable * already exists, its value is overriden. */ -static void +void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value) { - u_int i, namelen; char **env; + u_int envsize; + u_int i, namelen; + + /* + * If we're passed an uninitialized list, allocate a single null + * entry before continuing. + */ + if (*envp == NULL && *envsizep == 0) { + *envp = xmalloc(sizeof(char *)); + *envp[0] = NULL; + *envsizep = 1; + } /* * Find the slot where the value should be stored. If the variable @@ -834,12 +818,13 @@ child_set_env(char ***envp, u_int *envsizep, const char *name, xfree(env[i]); } else { /* New variable. Expand if necessary. */ - if (i >= (*envsizep) - 1) { - if (*envsizep >= 1000) - fatal("child_set_env: too many env vars," - " skipping: %.100s", name); - (*envsizep) += 50; - env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); + envsize = *envsizep; + if (i >= envsize - 1) { + if (envsize >= 1000) + fatal("child_set_env: too many env vars"); + envsize += 50; + env = (*envp) = xrealloc(env, envsize * sizeof(char *)); + *envsizep = envsize; } /* Need to set the NULL pointer at end of array beyond the new slot. */ env[i + 1] = NULL; @@ -895,6 +880,61 @@ read_environment_file(char ***env, u_int *envsize, fclose(f); } +#ifdef HAVE_ETC_DEFAULT_LOGIN +/* + * Return named variable from specified environment, or NULL if not present. + */ +static char * +child_get_env(char **env, const char *name) +{ + int i; + size_t len; + + len = strlen(name); + for (i=0; env[i] != NULL; i++) + if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') + return(env[i] + len + 1); + return NULL; +} + +/* + * Read /etc/default/login. + * We pick up the PATH (or SUPATH for root) and UMASK. + */ +static void +read_etc_default_login(char ***env, u_int *envsize, uid_t uid) +{ + char **tmpenv = NULL, *var; + u_int i, tmpenvsize = 0; + u_long mask; + + /* + * We don't want to copy the whole file to the child's environment, + * so we use a temporary environment and copy the variables we're + * interested in. + */ + read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); + + if (tmpenv == NULL) + return; + + if (uid == 0) + var = child_get_env(tmpenv, "SUPATH"); + else + var = child_get_env(tmpenv, "PATH"); + if (var != NULL) + child_set_env(env, envsize, "PATH", var); + + if ((var = child_get_env(tmpenv, "UMASK")) != NULL) + if (sscanf(var, "%5lo", &mask) == 1) + umask((mode_t)mask); + + for (i = 0; tmpenv[i] != NULL; i++) + xfree(tmpenv[i]); + xfree(tmpenv); +} +#endif /* HAVE_ETC_DEFAULT_LOGIN */ + void copy_environment(char **source, char ***env, u_int *envsize) { char *var_name, *var_val; @@ -913,7 +953,7 @@ void copy_environment(char **source, char ***env, u_int *envsize) debug3("Copy environment: %s=%s", var_name, var_val); child_set_env(env, envsize, var_name, var_val); - + xfree(var_name); } } @@ -923,7 +963,7 @@ do_setup_env(Session *s, const char *shell) { char buf[256]; u_int i, envsize; - char **env, *laddr; + char **env, *laddr, *path = NULL; struct passwd *pw = s->pw; /* Initialize the environment. */ @@ -939,6 +979,13 @@ do_setup_env(Session *s, const char *shell) copy_environment(environ, &env, &envsize); #endif +#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 + if (!options.use_login) { /* Set basic environment. */ child_set_env(&env, &envsize, "USER", pw->pw_name); @@ -960,12 +1007,15 @@ do_setup_env(Session *s, const char *shell) * needed for loading shared libraries. So the path better * remains intact here. */ -# ifdef SUPERUSER_PATH - child_set_env(&env, &envsize, "PATH", - s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH); -# else - child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); -# endif /* SUPERUSER_PATH */ +# ifdef HAVE_ETC_DEFAULT_LOGIN + read_etc_default_login(&env, &envsize, pw->pw_uid); + path = child_get_env(env, "PATH"); +# endif /* HAVE_ETC_DEFAULT_LOGIN */ + if (path == NULL || *path == '\0') { + child_set_env(&env, &envsize, "PATH", + s->pw->pw_uid == 0 ? + SUPERUSER_PATH : _PATH_STDPATH); + } # endif /* HAVE_CYGWIN */ #endif /* HAVE_LOGIN_CAP */ @@ -1045,8 +1095,13 @@ do_setup_env(Session *s, const char *shell) * been set by PAM. */ if (options.use_pam) { - char **p = fetch_pam_environment(); + 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); } @@ -1119,7 +1174,7 @@ do_rc_files(Session *s, const char *shell) if (debug_flag) { fprintf(stderr, "Running %.500s remove %.100s\n", - options.xauth_location, s->auth_display); + options.xauth_location, s->auth_display); fprintf(stderr, "%.500s add %.100s %.100s %.100s\n", options.xauth_location, s->auth_display, @@ -1185,6 +1240,12 @@ do_setusercontext(struct passwd *pw) # ifdef __bsdi__ setpgid(0, 0); # 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"); @@ -1211,12 +1272,14 @@ do_setusercontext(struct passwd *pw) endgrent(); # ifdef USE_PAM /* - * PAM credentials may take the form of supplementary groups. + * PAM credentials may take the form of supplementary groups. * These will have been wiped by the above initgroups() call. * Reestablish them here. */ - if (options.use_pam) + 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); @@ -1236,6 +1299,22 @@ do_setusercontext(struct passwd *pw) fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); } +static void +do_pwchange(Session *s) +{ + fprintf(stderr, "WARNING: Your password has expired.\n"); + if (s->ttyfd != -1) { + fprintf(stderr, + "You must change your password now and login again!\n"); + execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); + 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) { @@ -1257,6 +1336,40 @@ launch_login(struct passwd *pw, const char *hostname) exit(1); } +static void +child_close_fds(void) +{ + int i; + + if (packet_get_connection_in() == packet_get_connection_out()) + close(packet_get_connection_in()); + else { + close(packet_get_connection_in()); + close(packet_get_connection_out()); + } + /* + * Close all descriptors related to channels. They will still remain + * open in the parent. + */ + /* XXX better use close-on-exec? -markus */ + channel_close_all(); + + /* + * Close any extra file descriptors. Note that there may still be + * descriptors left by system functions. They will be closed later. + */ + endpwent(); + + /* + * Close any extra open file descriptors so that we don\'t have them + * hanging around in clients. Note that we want to do this after + * initgroups, because at least on Solaris 2.3 it leaves file + * descriptors open. + */ + for (i = 3; i < 64; i++) + close(i); +} + /* * Performs common processing for the child, such as setting up the * environment, closing extra file descriptors, setting the user and group @@ -1270,11 +1383,18 @@ do_child(Session *s, const char *command) char *argv[10]; const char *shell, *shell0, *hostname = NULL; struct passwd *pw = s->pw; - u_int i; /* 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; @@ -1325,39 +1445,39 @@ do_child(Session *s, const char *command) * closed before building the environment, as we call * get_remote_ipaddr there. */ - if (packet_get_connection_in() == packet_get_connection_out()) - close(packet_get_connection_in()); - else { - close(packet_get_connection_in()); - close(packet_get_connection_out()); - } - /* - * Close all descriptors related to channels. They will still remain - * open in the parent. - */ - /* XXX better use close-on-exec? -markus */ - channel_close_all(); + child_close_fds(); /* - * Close any extra file descriptors. Note that there may still be - * descriptors left by system functions. They will be closed later. + * Must take new environment into use so that .ssh/rc, + * /etc/ssh/sshrc and xauth are run in the proper environment. */ - endpwent(); + environ = env; +#if defined(KRB5) && defined(USE_AFS) /* - * Close any extra open file descriptors so that we don\'t have them - * hanging around in clients. Note that we want to do this after - * initgroups, because at least on Solaris 2.3 it leaves file - * descriptors open. + * At this point, we check to see if AFS is active and if we have + * a valid Kerberos 5 TGT. If so, it seems like a good idea to see + * if we can (and need to) extend the ticket into an AFS token. If + * we don't do this, we run into potential problems if the user's + * home directory is in AFS and it's not world-readable. */ - for (i = 3; i < 64; i++) - close(i); - /* - * Must take new environment into use so that .ssh/rc, - * /etc/ssh/sshrc and xauth are run in the proper environment. - */ - environ = env; + if (options.kerberos_get_afs_token && k_hasafs() && + (s->authctxt->krb5_ctx != NULL)) { + char cell[64]; + + debug("Getting AFS token"); + + k_setpag(); + + if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) + krb5_afslog(s->authctxt->krb5_ctx, + s->authctxt->krb5_fwd_ccache, cell, NULL); + + krb5_afslog_home(s->authctxt->krb5_ctx, + s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); + } +#endif /* Change current directory to the user\'s home directory. */ if (chdir(pw->pw_dir) < 0) { @@ -1480,7 +1600,7 @@ session_open(Authctxt *authctxt, int chanid) } s->authctxt = authctxt; s->pw = authctxt->pw; - if (s->pw == NULL) + if (s->pw == NULL || !authctxt->valid) fatal("no user for session %d", s->self); debug("session_open: session %d: link with channel %d", s->self, chanid); s->chanid = chanid; @@ -1602,11 +1722,6 @@ session_pty_req(Session *s) n_bytes = packet_remaining(); tty_parse_modes(s->ttyfd, &n_bytes); - /* - * Add a cleanup function to clear the utmp entry and record logout - * time in case we call fatal() (e.g., the connection gets closed). - */ - fatal_add_cleanup(session_pty_cleanup, (void *)s); if (!use_privsep) pty_setowner(s->pw, s->tty); @@ -1699,18 +1814,12 @@ session_break_req(Session *s) { u_int break_length; - break_length = packet_get_int(); + break_length = packet_get_int(); /* ignored */ packet_check_eom(); - if (s->ttyfd == -1) + if (s->ttyfd == -1 || + tcsendbreak(s->ttyfd, 0) < 0) return 0; - /* we will sleep from 500ms to 3000ms */ - break_length = MIN(break_length, 3000); - break_length = MAX(break_length, 500); - ioctl(s->ttyfd, TIOCSBRK, NULL); - /* should we care about EINTR? */ - usleep(break_length * 1000); - ioctl(s->ttyfd, TIOCCBRK, NULL); return 1; } @@ -1794,10 +1903,8 @@ session_set_fds(Session *s, int fdin, int fdout, int fderr) * (e.g., due to a dropped connection). */ void -session_pty_cleanup2(void *session) +session_pty_cleanup2(Session *s) { - Session *s = session; - if (s == NULL) { error("session_pty_cleanup: no session"); return; @@ -1828,9 +1935,9 @@ session_pty_cleanup2(void *session) } void -session_pty_cleanup(void *session) +session_pty_cleanup(Session *s) { - PRIVSEP(session_pty_cleanup2(session)); + PRIVSEP(session_pty_cleanup2(s)); } static char * @@ -1903,10 +2010,8 @@ void session_close(Session *s) { debug("session_close: session %d pid %ld", s->self, (long)s->pid); - if (s->ttyfd != -1) { - fatal_remove_cleanup(session_pty_cleanup, (void *)s); + if (s->ttyfd != -1) session_pty_cleanup(s); - } if (s->term) xfree(s->term); if (s->display) @@ -1955,10 +2060,8 @@ session_close_by_channel(int id, void *arg) * delay detach of session, but release pty, since * the fd's to the child are already closed */ - if (s->ttyfd != -1) { - fatal_remove_cleanup(session_pty_cleanup, (void *)s); + if (s->ttyfd != -1) session_pty_cleanup(s); - } return; } /* detach by removing callback */ @@ -1993,13 +2096,13 @@ session_tty_list(void) 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, cp, sizeof buf); @@ -2100,3 +2203,50 @@ do_authenticated2(Authctxt *authctxt) { 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); +}