X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/2a67a1d1a1e9867dc02bfb7671508537b29eebd1..6dc60241a6a563c6e5c214c7dae931aa452bb4b2:/openssh/session.c diff --git a/openssh/session.c b/openssh/session.c index e460dbc..b06bf38 100644 --- a/openssh/session.c +++ b/openssh/session.c @@ -1,3 +1,4 @@ +/* $OpenBSD: session.c,v 1.245 2009/01/22 09:46:01 djm Exp $ */ /* * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved @@ -33,20 +34,49 @@ */ #include "includes.h" -RCSID("$OpenBSD: session.c,v 1.154 2003/03/05 22:33:43 markus Exp $"); +#include +#include +#ifdef HAVE_SYS_STAT_H +# include +#endif +#include +#include +#include + +#include + +#include +#include +#ifdef HAVE_PATHS_H +#include +#endif +#include +#include +#include +#include +#include +#include +#include + +#include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" #include "ssh.h" #include "ssh1.h" #include "ssh2.h" -#include "xmalloc.h" #include "sshpty.h" #include "packet.h" #include "buffer.h" -#include "mpaux.h" +#include "match.h" #include "uidswap.h" #include "compat.h" #include "channels.h" -#include "bufaux.h" +#include "key.h" +#include "cipher.h" +#ifdef GSSAPI +#include "ssh-gss.h" +#endif +#include "hostfile.h" #include "auth.h" #include "auth-options.h" #include "pathnames.h" @@ -55,29 +85,32 @@ RCSID("$OpenBSD: session.c,v 1.154 2003/03/05 22:33:43 markus Exp $"); #include "sshlogin.h" #include "serverloop.h" #include "canohost.h" +#include "misc.h" #include "session.h" +#include "kex.h" #include "monitor_wrap.h" +#include "sftp.h" -#ifdef GSSAPI -#include "ssh-gss.h" +#if defined(KRB5) && defined(USE_AFS) +#include #endif -#ifdef HAVE_CYGWIN -#include -#include -#define is_winnt (GetVersion() < 0x80000000) -#endif +#define IS_INTERNAL_SFTP(c) \ + (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ + (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ + c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ + c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) /* func */ Session *session_new(void); -void session_set_fds(Session *, int, int, int); -void session_pty_cleanup(void *); +void session_set_fds(Session *, int, int, int, int); +void session_pty_cleanup(Session *); void session_proctitle(Session *); int session_setup_x11fwd(Session *); -void do_exec_pty(Session *, const char *); -void do_exec_no_pty(Session *, const char *); -void do_exec(Session *, const char *); +int do_exec_pty(Session *, const char *); +int do_exec_no_pty(Session *, const char *); +int do_exec(Session *, const char *); void do_login(Session *, const char *); #ifdef LOGIN_NEEDS_UTMPX static void do_pre_login(Session *s); @@ -104,22 +137,26 @@ extern int debug_flag; extern u_int utmp_len; extern int startup_pipe; extern void destroy_sensitive_data(void); +extern Buffer loginmsg; /* original command from peer. */ const char *original_command = NULL; /* data */ -#define MAX_SESSIONS 10 -Session sessions[MAX_SESSIONS]; +static int sessions_first_unused = -1; +static int sessions_nalloc = 0; +static Session *sessions = NULL; -#ifdef WITH_AIXAUTHENTICATE -char *aixloginmsg; -#endif /* WITH_AIXAUTHENTICATE */ +#define SUBSYSTEM_NONE 0 +#define SUBSYSTEM_EXT 1 +#define SUBSYSTEM_INT_SFTP 2 #ifdef HAVE_LOGIN_CAP login_cap_t *lc; #endif +static int is_child = 0; + /* Name and directory of socket for authentication agent forwarding. */ static char *auth_sock_name = NULL; static char *auth_sock_dir = NULL; @@ -127,10 +164,8 @@ static char *auth_sock_dir = NULL; /* removes the agent forwarding socket */ static void -auth_sock_cleanup_proc(void *_pw) +auth_sock_cleanup_proc(struct passwd *pw) { - struct passwd *pw = _pw; - if (auth_sock_name != NULL) { temporarily_use_uid(pw); unlink(auth_sock_name); @@ -144,7 +179,7 @@ static int auth_input_request_forwarding(struct passwd * pw) { Channel *nc; - int sock; + int sock = -1; struct sockaddr_un sunaddr; if (auth_sock_name != NULL) { @@ -156,72 +191,87 @@ auth_input_request_forwarding(struct passwd * pw) temporarily_use_uid(pw); /* Allocate a buffer for the socket name, and format the name. */ - auth_sock_name = xmalloc(MAXPATHLEN); - auth_sock_dir = xmalloc(MAXPATHLEN); - strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); + auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); /* Create private directory for socket */ if (mkdtemp(auth_sock_dir) == NULL) { packet_send_debug("Agent forwarding disabled: " "mkdtemp() failed: %.100s", strerror(errno)); restore_uid(); - xfree(auth_sock_name); xfree(auth_sock_dir); - auth_sock_name = NULL; auth_sock_dir = NULL; - return 0; + goto authsock_err; } - snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld", - auth_sock_dir, (long) getpid()); - /* delete agent socket on fatal() */ - fatal_add_cleanup(auth_sock_cleanup_proc, pw); + xasprintf(&auth_sock_name, "%s/agent.%ld", + auth_sock_dir, (long) getpid()); /* Create the socket. */ sock = socket(AF_UNIX, SOCK_STREAM, 0); - if (sock < 0) - packet_disconnect("socket: %.100s", strerror(errno)); + if (sock < 0) { + error("socket: %.100s", strerror(errno)); + restore_uid(); + goto authsock_err; + } /* Bind it to the name. */ memset(&sunaddr, 0, sizeof(sunaddr)); sunaddr.sun_family = AF_UNIX; strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); - if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) - packet_disconnect("bind: %.100s", strerror(errno)); + if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { + error("bind: %.100s", strerror(errno)); + restore_uid(); + goto authsock_err; + } /* Restore the privileged uid. */ restore_uid(); /* Start listening on the socket. */ - if (listen(sock, 5) < 0) - packet_disconnect("listen: %.100s", strerror(errno)); + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { + error("listen: %.100s", strerror(errno)); + goto authsock_err; + } /* Allocate a channel for the authentication agent socket. */ + /* this shouldn't matter if its hpn or not - cjr */ nc = channel_new("auth socket", SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, - 0, xstrdup("auth socket"), 1); - strlcpy(nc->path, auth_sock_name, sizeof(nc->path)); + 0, "auth socket", 1); + nc->path = xstrdup(auth_sock_name); return 1; + + authsock_err: + if (auth_sock_name != NULL) + xfree(auth_sock_name); + if (auth_sock_dir != NULL) { + rmdir(auth_sock_dir); + xfree(auth_sock_dir); + } + if (sock != -1) + close(sock); + auth_sock_name = NULL; + auth_sock_dir = NULL; + return 0; } +static void +display_loginmsg(void) +{ + if (buffer_len(&loginmsg) > 0) { + buffer_append(&loginmsg, "\0", 1); + printf("%s", (char *)buffer_ptr(&loginmsg)); + buffer_clear(&loginmsg); + } +} void do_authenticated(Authctxt *authctxt) { setproctitle("%s", authctxt->pw->pw_name); - /* - * Cancel the alarm we set to limit the time taken for - * authentication. - */ - alarm(0); - if (startup_pipe != -1) { - close(startup_pipe); - startup_pipe = -1; - } - /* setup the channel layer */ if (!no_port_forwarding_flag && options.allow_tcp_forwarding) channel_permit_all_opens(); @@ -231,10 +281,6 @@ do_authenticated(Authctxt *authctxt) else do_authenticated1(authctxt); - /* remove agent socket */ - if (auth_sock_name != NULL) - auth_sock_cleanup_proc(authctxt->pw); - #ifdef SESSION_HOOKS if (options.session_hooks_allow && options.session_hooks_shutdown_cmd) @@ -249,14 +295,8 @@ do_authenticated(Authctxt *authctxt) } } #endif -#ifdef KRB4 - if (options.kerberos_ticket_cleanup) - krb4_cleanup_proc(authctxt); -#endif -#ifdef KRB5 - if (options.kerberos_ticket_cleanup) - krb5_cleanup_proc(authctxt); -#endif + + do_cleanup(authctxt); } /* @@ -275,6 +315,10 @@ do_authenticated1(Authctxt *authctxt) u_int proto_len, data_len, dlen, compression_level = 0; s = session_new(); + if (s == NULL) { + error("no more sessions"); + return; + } s->authctxt = authctxt; s->pw = authctxt->pw; @@ -294,11 +338,11 @@ do_authenticated1(Authctxt *authctxt) compression_level = packet_get_int(); packet_check_eom(); if (compression_level < 1 || compression_level > 9) { - packet_send_debug("Received illegal compression level %d.", + packet_send_debug("Received invalid compression level %d.", compression_level); break; } - if (!options.compression) { + if (options.compression == COMP_NONE) { debug2("compression disabled"); break; } @@ -338,7 +382,8 @@ do_authenticated1(Authctxt *authctxt) break; case SSH_CMSG_AGENT_REQUEST_FORWARDING: - if (no_agent_forwarding_flag || compat13) { + if (!options.allow_agent_forwarding || + no_agent_forwarding_flag || compat13) { debug("Authentication agent forwarding not permitted for this authentication."); break; } @@ -356,7 +401,11 @@ do_authenticated1(Authctxt *authctxt) break; } debug("Received TCP/IP port forwarding request."); - channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports); + if (channel_input_port_forward_request(s->pw->pw_uid == 0, + options.gateway_ports) < 0) { + debug("Port forwarding failed."); + break; + } success = 1; break; @@ -365,67 +414,19 @@ do_authenticated1(Authctxt *authctxt) success = 1; break; -#if defined(AFS) || defined(KRB5) - case SSH_CMSG_HAVE_KERBEROS_TGT: - if (!options.kerberos_tgt_passing) { - verbose("Kerberos TGT passing disabled."); - } else { - char *kdata = packet_get_string(&dlen); - packet_check_eom(); - - /* XXX - 0x41, see creds_to_radix version */ - if (kdata[0] != 0x41) { -#ifdef KRB5 - krb5_data tgt; - tgt.data = kdata; - tgt.length = dlen; - - if (auth_krb5_tgt(s->authctxt, &tgt)) - success = 1; - else - verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user); -#endif /* KRB5 */ - } else { -#ifdef AFS - if (auth_krb4_tgt(s->authctxt, kdata)) - success = 1; - else - verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user); -#endif /* AFS */ - } - xfree(kdata); - } - break; -#endif /* AFS || KRB5 */ - -#ifdef AFS - case SSH_CMSG_HAVE_AFS_TOKEN: - if (!options.afs_token_passing || !k_hasafs()) { - verbose("AFS token passing disabled."); - } else { - /* Accept AFS token. */ - char *token = packet_get_string(&dlen); - packet_check_eom(); - - if (auth_afs_token(s->authctxt, token)) - success = 1; - else - verbose("AFS token refused for %.100s", - s->authctxt->user); - xfree(token); - } - break; -#endif /* AFS */ - case SSH_CMSG_EXEC_SHELL: case SSH_CMSG_EXEC_CMD: if (type == SSH_CMSG_EXEC_CMD) { command = packet_get_string(&dlen); debug("Exec command '%.500s'", command); - do_exec(s, command); + if (do_exec(s, command) != 0) + packet_disconnect( + "command execution failed"); xfree(command); } else { - do_exec(s, NULL); + if (do_exec(s, NULL) != 0) + packet_disconnect( + "shell execution failed"); } packet_check_eom(); session_close(s); @@ -436,7 +437,7 @@ do_authenticated1(Authctxt *authctxt) * Any unknown messages in this phase are ignored, * and a failure message is returned. */ - log("Unknown packet type received after authentication: %d", type); + logit("Unknown packet type received after authentication: %d", type); } packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); packet_send(); @@ -450,55 +451,84 @@ do_authenticated1(Authctxt *authctxt) } } +#define USE_PIPES /* * This is called to fork and execute a command when we have no tty. This * will call do_child from the child, and server_loop from the parent after * setting up file descriptors and such. */ -void +int do_exec_no_pty(Session *s, const char *command) { pid_t pid; #ifdef USE_PIPES int pin[2], pout[2], perr[2]; + /* Allocate pipes for communicating with the program. */ - if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) - packet_disconnect("Could not create pipes: %.100s", - strerror(errno)); -#else /* USE_PIPES */ + if (pipe(pin) < 0) { + error("%s: pipe in: %.100s", __func__, strerror(errno)); + return -1; + } + if (pipe(pout) < 0) { + error("%s: pipe out: %.100s", __func__, strerror(errno)); + close(pin[0]); + close(pin[1]); + return -1; + } + if (pipe(perr) < 0) { + error("%s: pipe err: %.100s", __func__, strerror(errno)); + close(pin[0]); + close(pin[1]); + close(pout[0]); + close(pout[1]); + return -1; + } +#else int inout[2], err[2]; + /* Uses socket pairs to communicate with the program. */ - if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || - socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) - packet_disconnect("Could not create socket pairs: %.100s", - strerror(errno)); -#endif /* USE_PIPES */ + if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { + error("%s: socketpair #1: %.100s", __func__, strerror(errno)); + return -1; + } + if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { + error("%s: socketpair #2: %.100s", __func__, strerror(errno)); + close(inout[0]); + close(inout[1]); + return -1; + } +#endif + if (s == NULL) fatal("do_exec_no_pty: no session"); session_proctitle(s); -#if defined(GSSAPI) - temporarily_use_uid(s->pw); - ssh_gssapi_storecreds(); - restore_uid(); -#endif - -#if defined(USE_PAM) - do_pam_session(s->pw->pw_name, NULL); - do_pam_setcred(1); - if (is_pam_password_change_required()) - packet_disconnect("Password change required but no " - "TTY available"); -#endif /* USE_PAM */ - /* Fork the child. */ - if ((pid = fork()) == 0) { - fatal_remove_all_cleanups(); + switch ((pid = fork())) { + case -1: + error("%s: fork: %.100s", __func__, strerror(errno)); +#ifdef USE_PIPES + close(pin[0]); + close(pin[1]); + close(pout[0]); + close(pout[1]); + close(perr[0]); + close(perr[1]); +#else + close(inout[0]); + close(inout[1]); + close(err[0]); + close(err[1]); +#endif + return -1; + case 0: + is_child = 1; /* Child. Reinitialize the log since the pid has changed. */ - log_init(__progname, options.log_level, options.log_facility, log_stderr); + log_init(__progname, options.log_level, + options.log_facility, log_stderr); /* * Create a new session and process group since the 4.4BSD @@ -528,7 +558,7 @@ do_exec_no_pty(Session *s, const char *command) if (dup2(perr[1], 2) < 0) perror("dup2 stderr"); close(perr[1]); -#else /* USE_PIPES */ +#else /* * Redirect stdin, stdout, and stderr. Stdin and stdout will * use the same socket, as some programs (particularly rdist) @@ -538,11 +568,14 @@ do_exec_no_pty(Session *s, const char *command) close(err[1]); if (dup2(inout[0], 0) < 0) /* stdin */ perror("dup2 stdin"); - if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ + if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ perror("dup2 stdout"); + close(inout[0]); if (dup2(err[0], 2) < 0) /* stderr */ perror("dup2 stderr"); -#endif /* USE_PIPES */ + close(err[0]); +#endif + #ifdef _UNICOS cray_init_job(s->pw); /* set up cray jid and tmpdir */ @@ -551,7 +584,10 @@ do_exec_no_pty(Session *s, const char *command) /* Do processing for the child (exec command etc). */ do_child(s, command); /* NOTREACHED */ + default: + break; } + #ifdef _UNICOS signal(WJSIGNAL, cray_job_termination_handler); #endif /* _UNICOS */ @@ -559,11 +595,18 @@ do_exec_no_pty(Session *s, const char *command) if (is_winnt) cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); #endif - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); + s->pid = pid; /* Set interactive/non-interactive mode. */ packet_set_interactive(s->display != NULL); + + /* + * Clear loginmsg, since it's the child's responsibility to display + * it to the user, otherwise multiple sessions may accumulate + * multiple copies of the login messages. + */ + buffer_clear(&loginmsg); + #ifdef USE_PIPES /* We are the parent. Close the child sides of the pipes. */ close(pin[0]); @@ -571,13 +614,17 @@ do_exec_no_pty(Session *s, const char *command) close(perr[1]); if (compat20) { - session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]); + if (s->is_subsystem) { + close(perr[0]); + perr[0] = -1; + } + session_set_fds(s, pin[1], pout[0], perr[0], 0); } else { /* Enter the interactive session. */ server_loop(pid, pin[1], pout[0], perr[0]); /* server_loop has closed pin[1], pout[0], and perr[0]. */ } -#else /* USE_PIPES */ +#else /* We are the parent. Close the child sides of the socket pairs. */ close(inout[0]); close(err[0]); @@ -587,12 +634,16 @@ do_exec_no_pty(Session *s, const char *command) * handle the case that fdin and fdout are the same. */ if (compat20) { - session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]); + session_set_fds(s, inout[1], inout[1], + s->is_subsystem ? -1 : err[1], 0); + if (s->is_subsystem) + close(err[1]); } else { server_loop(pid, inout[1], inout[1], err[1]); /* server_loop has closed inout[1] and err[1]. */ } -#endif /* USE_PIPES */ +#endif + return 0; } /* @@ -601,7 +652,7 @@ do_exec_no_pty(Session *s, const char *command) * setting up file descriptors, controlling tty, updating wtmp, utmp, * lastlog, and other such operations. */ -void +int do_exec_pty(Session *s, const char *command) { int fdout, ptyfd, ttyfd, ptymaster; @@ -612,23 +663,46 @@ do_exec_pty(Session *s, const char *command) ptyfd = s->ptyfd; ttyfd = s->ttyfd; -#if defined(GSSAPI) - temporarily_use_uid(s->pw); - ssh_gssapi_storecreds(); - restore_uid(); -#endif - -#if defined(USE_PAM) - do_pam_session(s->pw->pw_name, s->tty); - do_pam_setcred(1); -#endif + /* + * Create another descriptor of the pty master side for use as the + * standard input. We could use the original descriptor, but this + * simplifies code in server_loop. The descriptor is bidirectional. + * Do this before forking (and cleanup in the child) so as to + * detect and gracefully fail out-of-fd conditions. + */ + if ((fdout = dup(ptyfd)) < 0) { + error("%s: dup #1: %s", __func__, strerror(errno)); + close(ttyfd); + close(ptyfd); + return -1; + } + /* we keep a reference to the pty master */ + if ((ptymaster = dup(ptyfd)) < 0) { + error("%s: dup #2: %s", __func__, strerror(errno)); + close(ttyfd); + close(ptyfd); + close(fdout); + return -1; + } /* Fork the child. */ - if ((pid = fork()) == 0) { - fatal_remove_all_cleanups(); + switch ((pid = fork())) { + case -1: + error("%s: fork: %.100s", __func__, strerror(errno)); + close(fdout); + close(ptymaster); + close(ttyfd); + close(ptyfd); + return -1; + case 0: + is_child = 1; + + close(fdout); + close(ptymaster); /* Child. Reinitialize the log because the pid has changed. */ - log_init(__progname, options.log_level, options.log_facility, log_stderr); + log_init(__progname, options.log_level, + options.log_facility, log_stderr); /* Close the master side of the pseudo tty. */ close(ptyfd); @@ -659,11 +733,16 @@ do_exec_pty(Session *s, const char *command) do_pre_login(s); # endif #endif - - /* Do common processing for the child, such as execing the command. */ - do_child(s, command); - /* NOTREACHED */ + /* + * Do common processing for the child, such as execing + * the command. + */ + do_child(s, command); + /* NOTREACHED */ + default: + break; } + #ifdef _UNICOS signal(WJSIGNAL, cray_job_termination_handler); #endif /* _UNICOS */ @@ -671,36 +750,22 @@ do_exec_pty(Session *s, const char *command) if (is_winnt) cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); #endif - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); + s->pid = pid; /* Parent. Close the slave side of the pseudo tty. */ close(ttyfd); - /* - * Create another descriptor of the pty master side for use as the - * standard input. We could use the original descriptor, but this - * simplifies code in server_loop. The descriptor is bidirectional. - */ - fdout = dup(ptyfd); - if (fdout < 0) - packet_disconnect("dup #1 failed: %.100s", strerror(errno)); - - /* we keep a reference to the pty master */ - ptymaster = dup(ptyfd); - if (ptymaster < 0) - packet_disconnect("dup #2 failed: %.100s", strerror(errno)); - s->ptymaster = ptymaster; - /* Enter interactive session. */ + s->ptymaster = ptymaster; packet_set_interactive(1); if (compat20) { - session_set_fds(s, ptyfd, fdout, -1); + session_set_fds(s, ptyfd, fdout, -1, 1); } else { server_loop(pid, ptyfd, fdout, -1); /* server_loop _has_ closed ptyfd and fdout. */ } + return 0; } #ifdef LOGIN_NEEDS_UTMPX @@ -719,14 +784,14 @@ do_pre_login(Session *s) fromlen = sizeof(from); if (packet_connection_is_on_socket()) { if (getpeername(packet_get_connection_in(), - (struct sockaddr *) & from, &fromlen) < 0) { + (struct sockaddr *)&from, &fromlen) < 0) { debug("getpeername: %.100s", strerror(errno)); - fatal_cleanup(); + cleanup_exit(255); } } record_utmp_only(pid, s->tty, s->pw->pw_name, - get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping), + get_remote_name_or_ip(utmp_len, options.use_dns), (struct sockaddr *)&from, fromlen); } #endif @@ -735,48 +800,81 @@ do_pre_login(Session *s) * This is called to fork and execute a command. If another command is * to be forced, execute that instead. */ -void +int do_exec(Session *s, const char *command) { -#if defined(SESSION_HOOKS) - if (options.session_hooks_allow && - (options.session_hooks_startup_cmd || - options.session_hooks_shutdown_cmd)) - { - char env_file[1000]; - struct stat st; - do - { - snprintf(env_file, - sizeof(env_file), - "/tmp/ssh_env_%d%d%d", - getuid(), - getpid(), - rand()); - } while (stat(env_file, &st)==0); - s->authctxt->session_env_file = strdup(env_file); - } -#endif - if (forced_command) { + int ret; + + if (options.adm_forced_command) { + original_command = command; + command = options.adm_forced_command; + if (IS_INTERNAL_SFTP(command)) + s->is_subsystem = SUBSYSTEM_INT_SFTP; + else if (s->is_subsystem) + s->is_subsystem = SUBSYSTEM_EXT; + debug("Forced command (config) '%.900s'", command); + } else if (forced_command) { original_command = command; command = forced_command; - debug("Forced command '%.900s'", command); + if (IS_INTERNAL_SFTP(command)) + s->is_subsystem = SUBSYSTEM_INT_SFTP; + else if (s->is_subsystem) + s->is_subsystem = SUBSYSTEM_EXT; + debug("Forced command (key option) '%.900s'", command); + } + +#if defined(SESSION_HOOKS) + if (options.session_hooks_allow && + (options.session_hooks_startup_cmd || + options.session_hooks_shutdown_cmd)) + { + char env_file[1000]; + struct stat st; + do + { + snprintf(env_file, + sizeof(env_file), + "/tmp/ssh_env_%d%d%d", + getuid(), + getpid(), + rand()); + } while (stat(env_file, &st)==0); + s->authctxt->session_env_file = strdup(env_file); } +#endif +#ifdef SSH_AUDIT_EVENTS + if (command != NULL) + PRIVSEP(audit_run_command(command)); + else if (s->ttyfd == -1) { + char *shell = s->pw->pw_shell; + + if (shell[0] == '\0') /* empty shell means /bin/sh */ + shell =_PATH_BSHELL; + PRIVSEP(audit_run_command(shell)); + } +#endif if (s->ttyfd != -1) - do_exec_pty(s, command); + ret = do_exec_pty(s, command); else - do_exec_no_pty(s, command); + ret = do_exec_no_pty(s, command); original_command = NULL; -} + /* + * Clear loginmsg: it's the child's responsibility to display + * it to the user, otherwise multiple sessions may accumulate + * multiple copies of the login messages. + */ + buffer_clear(&loginmsg); + + return ret; +} /* administrative, login(1)-like work */ void do_login(Session *s, const char *command) { - char *time_string; socklen_t fromlen; struct sockaddr_storage from; struct passwd * pw = s->pw; @@ -792,7 +890,7 @@ 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); } } @@ -800,7 +898,7 @@ do_login(Session *s, const char *command) if (!use_privsep) record_login(pid, s->tty, pw->pw_name, pw->pw_uid, get_remote_name_or_ip(utmp_len, - options.verify_reverse_mapping), + options.use_dns), (struct sockaddr *)&from, fromlen); #ifdef USE_PAM @@ -808,36 +906,18 @@ do_login(Session *s, const char *command) * If password change is needed, do it now. * This needs to occur before the ~/.hushlogin check. */ - if (is_pam_password_change_required()) { - print_pam_messages(); + if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) { + display_loginmsg(); do_pam_chauthtok(); + s->authctxt->force_pwchange = 0; + /* XXX - signal [net] parent to enable forwardings */ } #endif if (check_quietlogin(s, command)) return; -#ifdef USE_PAM - if (!is_pam_password_change_required()) - print_pam_messages(); -#endif /* USE_PAM */ -#ifdef WITH_AIXAUTHENTICATE - if (aixloginmsg && *aixloginmsg) - printf("%s\n", aixloginmsg); -#endif /* WITH_AIXAUTHENTICATE */ - -#ifndef NO_SSH_LASTLOG - if (options.print_lastlog && s->last_login_time != 0) { - time_string = ctime(&s->last_login_time); - if (strchr(time_string, '\n')) - *strchr(time_string, '\n') = 0; - if (strcmp(s->hostname, "") == 0) - printf("Last login: %s\r\n", time_string); - else - printf("Last login: %s from %s\r\n", time_string, - s->hostname); - } -#endif /* NO_SSH_LASTLOG */ + display_loginmsg(); do_motd(); } @@ -893,14 +973,25 @@ check_quietlogin(Session *s, const char *command) /* * Sets the value of the given variable in the environment. If the variable - * already exists, its value is overriden. + * already exists, its value is overridden. */ void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value) { - u_int i, namelen; char **env; + u_int envsize; + u_int i, namelen; + + /* + * If we're passed an uninitialized list, allocate a single null + * entry before continuing. + */ + if (*envp == NULL && *envsizep == 0) { + *envp = xmalloc(sizeof(char *)); + *envp[0] = NULL; + *envsizep = 1; + } /* * Find the slot where the value should be stored. If the variable @@ -917,12 +1008,13 @@ 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; @@ -959,8 +1051,9 @@ read_environment_file(char ***env, u_int *envsize, ; if (!*cp || *cp == '#' || *cp == '\n') continue; - if (strchr(cp, '\n')) - *strchr(cp, '\n') = '\0'; + + cp[strcspn(cp, "\n")] = '\0'; + value = strchr(cp, '='); if (value == NULL) { fprintf(stderr, "Bad line %u in %.100s\n", lineno, @@ -1089,7 +1182,63 @@ void execute_session_hook(char* prog, Authctxt *authctxt, } #endif -void copy_environment(char **source, char ***env, u_int *envsize) +#ifdef HAVE_ETC_DEFAULT_LOGIN +/* + * Return named variable from specified environment, or NULL if not present. + */ +static char * +child_get_env(char **env, const char *name) +{ + int i; + size_t len; + + len = strlen(name); + for (i=0; env[i] != NULL; i++) + if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') + return(env[i] + len + 1); + return NULL; +} + +/* + * Read /etc/default/login. + * We pick up the PATH (or SUPATH for root) and UMASK. + */ +static void +read_etc_default_login(char ***env, u_int *envsize, uid_t uid) +{ + char **tmpenv = NULL, *var; + u_int i, tmpenvsize = 0; + u_long mask; + + /* + * We don't want to copy the whole file to the child's environment, + * so we use a temporary environment and copy the variables we're + * interested in. + */ + read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); + + if (tmpenv == NULL) + return; + + if (uid == 0) + var = child_get_env(tmpenv, "SUPATH"); + else + var = child_get_env(tmpenv, "PATH"); + if (var != NULL) + child_set_env(env, envsize, "PATH", var); + + if ((var = child_get_env(tmpenv, "UMASK")) != NULL) + if (sscanf(var, "%5lo", &mask) == 1) + umask((mode_t)mask); + + for (i = 0; tmpenv[i] != NULL; i++) + xfree(tmpenv[i]); + xfree(tmpenv); +} +#endif /* HAVE_ETC_DEFAULT_LOGIN */ + +void +copy_environment(char **source, char ***env, u_int *envsize) { char *var_name, *var_val; int i; @@ -1107,7 +1256,7 @@ 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); } } @@ -1119,10 +1268,13 @@ do_setup_env(Session *s, const char *shell) u_int i, envsize; char **env, *laddr; struct passwd *pw = s->pw; +#ifndef HAVE_LOGIN_CAP + char *path = NULL; +#endif /* Initialize the environment. */ envsize = 100; - env = xmalloc(envsize * sizeof(char *)); + env = xcalloc(envsize, sizeof(char *)); env[0] = NULL; #ifdef HAVE_CYGWIN @@ -1130,18 +1282,28 @@ do_setup_env(Session *s, const char *shell) * The Windows environment contains some setting which are * important for a running system. They must not be dropped. */ - copy_environment(environ, &env, &envsize); + { + char **p; + + p = fetch_windows_environment(); + copy_environment(p, &env, &envsize); + free_windows_environment(p); + } #endif #ifdef GSSAPI - /* Allow any GSSAPI methods that we've used to alter + /* Allow any GSSAPI methods that we've used to alter * the childs environment as they see fit */ - ssh_gssapi_do_child(&env,&envsize); + ssh_gssapi_do_child(&env, &envsize); #endif if (!options.use_login) { /* Set basic environment. */ + for (i = 0; i < s->num_env; i++) + child_set_env(&env, &envsize, s->env[i].name, + s->env[i].val); + child_set_env(&env, &envsize, "USER", pw->pw_name); child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); #ifdef _AIX @@ -1161,15 +1323,15 @@ 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 */ - if (getenv("LD_LIBRARY_PATH")) - child_set_env(&env, &envsize, "LD_LIBRARY_PATH", - getenv("LD_LIBRARY_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 */ @@ -1183,6 +1345,23 @@ do_setup_env(Session *s, const char *shell) if (getenv("TZ")) child_set_env(&env, &envsize, "TZ", getenv("TZ")); +#ifdef GSI /* GSI shared libs typically installed in non-system locations. */ + { + char *cp; + + if ((cp = getenv("LD_LIBRARY_PATH")) != NULL) + child_set_env(&env, &envsize, "LD_LIBRARY_PATH", cp); + if ((cp = getenv("LIBPATH")) != NULL) + child_set_env(&env, &envsize, "LIBPATH", cp); + if ((cp = getenv("SHLIB_PATH")) != NULL) + child_set_env(&env, &envsize, "SHLIB_PATH", cp); + if ((cp = getenv("LD_LIBRARYN32_PATH")) != NULL) + child_set_env(&env, &envsize, "LD_LIBRARYN32_PATH",cp); + if ((cp = getenv("LD_LIBRARY64_PATH")) != NULL) + child_set_env(&env, &envsize, "LD_LIBRARY64_PATH",cp); + } +#endif + /* Set custom environment options from RSA authentication. */ if (!options.use_login) { while (custom_environment) { @@ -1227,35 +1406,44 @@ do_setup_env(Session *s, const char *shell) child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir); #endif /* _UNICOS */ + /* + * Since we clear KRB5CCNAME at startup, if it's set now then it + * must have been set by a native authentication method (eg AIX or + * SIA), so copy it to the child. + */ + { + char *cp; + + if ((cp = getenv("KRB5CCNAME")) != NULL) + child_set_env(&env, &envsize, "KRB5CCNAME", cp); + } + #ifdef _AIX { char *cp; if ((cp = getenv("AUTHSTATE")) != NULL) child_set_env(&env, &envsize, "AUTHSTATE", cp); - if ((cp = getenv("KRB5CCNAME")) != NULL) - child_set_env(&env, &envsize, "KRB5CCNAME", cp); read_environment_file(&env, &envsize, "/etc/environment"); } #endif -#ifdef KRB4 - if (s->authctxt->krb4_ticket_file) - child_set_env(&env, &envsize, "KRBTKFILE", - s->authctxt->krb4_ticket_file); -#endif #ifdef KRB5 - if (s->authctxt->krb5_ticket_file) + if (s->authctxt->krb5_ccname) child_set_env(&env, &envsize, "KRB5CCNAME", - s->authctxt->krb5_ticket_file); + s->authctxt->krb5_ccname); #endif #ifdef USE_PAM /* * Pull in any environment variables that may have * been set by PAM. */ - { + if (options.use_pam) { char **p; + p = fetch_pam_child_environment(); + copy_environment(p, &env, &envsize); + free_pam_environment(p); + p = fetch_pam_environment(); copy_environment(p, &env, &envsize); free_pam_environment(p); @@ -1296,8 +1484,9 @@ do_rc_files(Session *s, const char *shell) do_xauth = s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; - /* ignore _PATH_SSH_USER_RC for subsystems */ - if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) { + /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ + if (!s->is_subsystem && options.adm_forced_command == NULL && + !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) { snprintf(cmd, sizeof cmd, "%s -c '%s %s'", shell, _PATH_BSHELL, _PATH_SSH_USER_RC); if (debug_flag) @@ -1329,7 +1518,7 @@ 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, @@ -1368,7 +1557,7 @@ do_nologin(struct passwd *pw) #endif if (f) { /* /etc/nologin exists. Print its contents and exit. */ - log("User %.100s not allowed because %s exists", + logit("User %.100s not allowed because %s exists", pw->pw_name, _PATH_NOLOGIN); while (fgets(buf, sizeof(buf), f)) fputs(buf, stderr); @@ -1378,24 +1567,92 @@ do_nologin(struct passwd *pw) } } +/* + * Chroot into a directory after checking it for safety: all path components + * must be root-owned directories with strict permissions. + */ +static void +safely_chroot(const char *path, uid_t uid) +{ + const char *cp; + char component[MAXPATHLEN]; + struct stat st; + + if (*path != '/') + fatal("chroot path does not begin at root"); + if (strlen(path) >= sizeof(component)) + fatal("chroot path too long"); + + /* + * Descend the path, checking that each component is a + * root-owned directory with strict permissions. + */ + for (cp = path; cp != NULL;) { + if ((cp = strchr(cp, '/')) == NULL) + strlcpy(component, path, sizeof(component)); + else { + cp++; + memcpy(component, path, cp - path); + component[cp - path] = '\0'; + } + + debug3("%s: checking '%s'", __func__, component); + + if (stat(component, &st) != 0) + fatal("%s: stat(\"%s\"): %s", __func__, + component, strerror(errno)); + if (st.st_uid != 0 || (st.st_mode & 022) != 0) + fatal("bad ownership or modes for chroot " + "directory %s\"%s\"", + cp == NULL ? "" : "component ", component); + if (!S_ISDIR(st.st_mode)) + fatal("chroot path %s\"%s\" is not a directory", + cp == NULL ? "" : "component ", component); + + } + + if (chdir(path) == -1) + fatal("Unable to chdir to chroot path \"%s\": " + "%s", path, strerror(errno)); + if (chroot(path) == -1) + fatal("chroot(\"%s\"): %s", path, strerror(errno)); + if (chdir("/") == -1) + fatal("%s: chdir(/) after chroot: %s", + __func__, strerror(errno)); + verbose("Changed root directory to \"%s\"", path); +} + /* Set login name, uid, gid, and groups. */ void do_setusercontext(struct passwd *pw) { + char *chroot_path, *tmp; + +#ifdef WITH_SELINUX + /* Cache selinux status for later use */ + (void)ssh_selinux_enabled(); +#endif + #ifndef HAVE_CYGWIN if (getuid() == 0 || geteuid() == 0) #endif /* HAVE_CYGWIN */ { #ifdef HAVE_SETPCRED - setpcred(pw->pw_name); + 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 USE_PAM + if (options.use_pam) { + do_pam_setcred(use_privsep); + } +# endif /* USE_PAM */ if (setusercontext(lc, pw, pw->pw_uid, - (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) { + (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { perror("unable to set user context"); exit(1); } @@ -1420,18 +1677,44 @@ do_setusercontext(struct passwd *pw) endgrent(); # ifdef USE_PAM /* - * PAM credentials may take the form of supplementary groups. + * PAM credentials may take the form of supplementary groups. * These will have been wiped by the above initgroups() call. * Reestablish them here. */ - do_pam_setcred(0); + if (options.use_pam) { + do_pam_setcred(use_privsep); + } # endif /* USE_PAM */ # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) irix_setusercontext(pw); -# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */ +# endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */ # ifdef _AIX aix_usrinfo(pw); # endif /* _AIX */ +# ifdef USE_LIBIAF + if (set_id(pw->pw_name) != 0) { + exit(1); + } +# endif /* USE_LIBIAF */ +#endif + + if (options.chroot_directory != NULL && + strcasecmp(options.chroot_directory, "none") != 0) { + tmp = tilde_expand_filename(options.chroot_directory, + pw->pw_uid); + chroot_path = percent_expand(tmp, "h", pw->pw_dir, + "u", pw->pw_name, (char *)NULL); + safely_chroot(chroot_path, pw->pw_uid); + free(tmp); + free(chroot_path); + } + +#ifdef HAVE_LOGIN_CAP + if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { + perror("unable to set user context (setuser)"); + exit(1); + } +#else /* Permanently switch to the desired uid. */ permanently_set_uid(pw); #endif @@ -1442,6 +1725,32 @@ do_setusercontext(struct passwd *pw) #endif if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); + +#ifdef WITH_SELINUX + ssh_selinux_setup_exec_context(pw->pw_name); +#endif +} + +static void +do_pwchange(Session *s) +{ + fflush(NULL); + fprintf(stderr, "WARNING: Your password has expired.\n"); + if (s->ttyfd != -1) { + fprintf(stderr, + "You must change your password now and login again!\n"); +#ifdef PASSWD_NEEDS_USERNAME + execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name, + (char *)NULL); +#else + execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); +#endif + perror("passwd"); + } else { + fprintf(stderr, + "Password change required but no TTY available.\n"); + } + exit(1); } static void @@ -1465,20 +1774,55 @@ launch_login(struct passwd *pw, const char *hostname) exit(1); } +static void +child_close_fds(void) +{ + int i; + + if (packet_get_connection_in() == packet_get_connection_out()) + close(packet_get_connection_in()); + else { + close(packet_get_connection_in()); + close(packet_get_connection_out()); + } + /* + * Close all descriptors related to channels. They will still remain + * open in the parent. + */ + /* XXX better use close-on-exec? -markus */ + channel_close_all(); + + /* + * Close any extra file descriptors. Note that there may still be + * descriptors left by system functions. They will be closed later. + */ + endpwent(); + + /* + * Close any extra open file descriptors so that we don't have them + * hanging around in clients. Note that we want to do this after + * initgroups, because at least on Solaris 2.3 it leaves file + * descriptors open. + */ + for (i = 3; i < 64; i++) + close(i); +} + /* * Performs common processing for the child, such as setting up the * environment, closing extra file descriptors, setting the user and group * ids, and executing the command or shell. */ +#define ARGV_MAX 10 void do_child(Session *s, const char *command) { extern char **environ; char **env; - char *argv[10]; + char *argv[ARGV_MAX]; const char *shell, *shell0, *hostname = NULL; struct passwd *pw = s->pw; - u_int i; + int r = 0; #ifdef AFS_KRB5 /* Default place to look for aklog. */ @@ -1495,6 +1839,14 @@ do_child(Session *s, const char *command) /* remove hostkey from the child's memory */ destroy_sensitive_data(); + /* Force a password change */ + if (s->authctxt->force_pwchange) { + do_setusercontext(pw); + child_close_fds(); + do_pwchange(s); + exit(1); + } + /* login(1) is only called if we execute the login shell */ if (options.use_login && command != NULL) options.use_login = 0; @@ -1513,11 +1865,28 @@ do_child(Session *s, const char *command) if (!check_quietlogin(s, command)) do_motd(); #else /* HAVE_OSF_SIA */ - do_nologin(pw); + /* When PAM is enabled we rely on it to do the nologin check */ + if (!options.use_pam) + do_nologin(pw); do_setusercontext(pw); + /* + * PAM session modules in do_setusercontext may have + * generated messages, so if this in an interactive + * login then display them too. + */ + if (!check_quietlogin(s, command)) + display_loginmsg(); #endif /* HAVE_OSF_SIA */ } +#ifdef USE_PAM + if (options.use_pam && !options.use_login && !is_pam_session_open()) { + debug3("PAM session not opened, exiting"); + display_loginmsg(); + exit(254); + } +#endif + /* * Get the shell from the password data. An empty shell field is * legal, and means /bin/sh. @@ -1537,7 +1906,7 @@ do_child(Session *s, const char *command) /* we have to stash the hostname before we close our socket. */ if (options.use_login) hostname = get_remote_name_or_ip(utmp_len, - options.verify_reverse_mapping); + options.use_dns); /* * Close the connection descriptors; note that this is the child, and * the server will still have the socket open, and it is important @@ -1545,39 +1914,39 @@ do_child(Session *s, const char *command) * closed before building the environment, as we call * get_remote_ipaddr there. */ - if (packet_get_connection_in() == packet_get_connection_out()) - close(packet_get_connection_in()); - else { - close(packet_get_connection_in()); - close(packet_get_connection_out()); - } - /* - * Close all descriptors related to channels. They will still remain - * open in the parent. - */ - /* XXX better use close-on-exec? -markus */ - channel_close_all(); + child_close_fds(); /* - * Close any extra file descriptors. Note that there may still be - * descriptors left by system functions. They will be closed later. + * Must take new environment into use so that .ssh/rc, + * /etc/ssh/sshrc and xauth are run in the proper environment. */ - endpwent(); + environ = env; +#if defined(KRB5) && defined(USE_AFS) /* - * Close any extra open file descriptors so that we don\'t have them - * hanging around in clients. Note that we want to do this after - * initgroups, because at least on Solaris 2.3 it leaves file - * descriptors open. + * At this point, we check to see if AFS is active and if we have + * a valid Kerberos 5 TGT. If so, it seems like a good idea to see + * if we can (and need to) extend the ticket into an AFS token. If + * we don't do this, we run into potential problems if the user's + * home directory is in AFS and it's not world-readable. */ - for (i = 3; i < 64; i++) - close(i); - /* - * Must take new environment into use so that .ssh/rc, - * /etc/ssh/sshrc and xauth are run in the proper environment. - */ - environ = env; + if (options.kerberos_get_afs_token && k_hasafs() && + (s->authctxt->krb5_ctx != NULL)) { + char cell[64]; + + debug("Getting AFS token"); + + k_setpag(); + + if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) + krb5_afslog(s->authctxt->krb5_ctx, + s->authctxt->krb5_fwd_ccache, cell, NULL); + + krb5_afslog_home(s->authctxt->krb5_ctx, + s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); + } +#endif #ifdef AFS_KRB5 @@ -1613,33 +1982,44 @@ do_child(Session *s, const char *command) options.session_hooks_shutdown_cmd != NULL); } #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 */ - - /* Change current directory to the user\'s home directory. */ + /* Change current directory to the user's home directory. */ if (chdir(pw->pw_dir) < 0) { - fprintf(stderr, "Could not chdir to home directory %s: %s\n", - pw->pw_dir, strerror(errno)); + /* Suppress missing homedir warning for chroot case */ #ifdef HAVE_LOGIN_CAP - if (login_getcapbool(lc, "requirehome", 0)) - exit(1); + r = login_getcapbool(lc, "requirehome", 0); #endif + if (r || options.chroot_directory == NULL) + fprintf(stderr, "Could not chdir to home " + "directory %s: %s\n", pw->pw_dir, + strerror(errno)); + if (r) + exit(1); } + closefrom(STDERR_FILENO + 1); + if (!options.use_login) do_rc_files(s, shell); /* restore SIGPIPE for child */ - signal(SIGPIPE, SIG_DFL); + signal(SIGPIPE, SIG_DFL); + + if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { + extern int optind, optreset; + int i; + char *p, *args; + + setproctitle("%s@internal-sftp-server", s->pw->pw_name); + args = xstrdup(command ? command : "sftp-server"); + for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) + if (i < ARGV_MAX - 1) + argv[i++] = p; + argv[i] = NULL; + optind = optreset = 1; + __progname = argv[0]; + exit(sftp_server_main(i, argv, s->pw)); + } if (options.use_login) { launch_login(pw, hostname); @@ -1692,42 +2072,79 @@ do_child(Session *s, const char *command) exit(1); } +void +session_unused(int id) +{ + debug3("%s: session id %d unused", __func__, id); + if (id >= options.max_sessions || + id >= sessions_nalloc) { + fatal("%s: insane session id %d (max %d nalloc %d)", + __func__, id, options.max_sessions, sessions_nalloc); + } + bzero(&sessions[id], sizeof(*sessions)); + sessions[id].self = id; + sessions[id].used = 0; + sessions[id].chanid = -1; + sessions[id].ptyfd = -1; + sessions[id].ttyfd = -1; + sessions[id].ptymaster = -1; + sessions[id].x11_chanids = NULL; + sessions[id].next_unused = sessions_first_unused; + sessions_first_unused = id; +} + Session * session_new(void) { - int i; - static int did_init = 0; - if (!did_init) { - debug("session_new: init"); - for (i = 0; i < MAX_SESSIONS; i++) { - sessions[i].used = 0; + Session *s, *tmp; + + if (sessions_first_unused == -1) { + if (sessions_nalloc >= options.max_sessions) + return NULL; + debug2("%s: allocate (allocated %d max %d)", + __func__, sessions_nalloc, options.max_sessions); + tmp = xrealloc(sessions, sessions_nalloc + 1, + sizeof(*sessions)); + if (tmp == NULL) { + error("%s: cannot allocate %d sessions", + __func__, sessions_nalloc + 1); + return NULL; } - did_init = 1; + sessions = tmp; + session_unused(sessions_nalloc++); } - for (i = 0; i < MAX_SESSIONS; i++) { - Session *s = &sessions[i]; - if (! s->used) { - memset(s, 0, sizeof(*s)); - s->chanid = -1; - s->ptyfd = -1; - s->ttyfd = -1; - s->used = 1; - s->self = i; - debug("session_new: session %d", i); - return s; - } + + if (sessions_first_unused >= sessions_nalloc || + sessions_first_unused < 0) { + fatal("%s: insane first_unused %d max %d nalloc %d", + __func__, sessions_first_unused, options.max_sessions, + sessions_nalloc); } - return NULL; + + s = &sessions[sessions_first_unused]; + if (s->used) { + fatal("%s: session %d already used", + __func__, sessions_first_unused); + } + sessions_first_unused = s->next_unused; + s->used = 1; + s->next_unused = -1; + debug("session_new: session %d", s->self); + + return s; } static void session_dump(void) { int i; - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; - debug("dump: used %d session %d %p channel %d pid %ld", + + debug("dump: used %d next_unused %d session %d %p " + "channel %d pid %ld", s->used, + s->next_unused, s->self, s, s->chanid, @@ -1746,7 +2163,7 @@ 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; @@ -1757,7 +2174,7 @@ Session * session_by_tty(char *tty) { int i; - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { debug("session_by_tty: session %d tty %s", i, tty); @@ -1773,10 +2190,11 @@ static Session * session_by_channel(int id) { int i; - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; if (s->used && s->chanid == id) { - debug("session_by_channel: session %d channel %d", i, id); + debug("session_by_channel: session %d channel %d", + i, id); return s; } } @@ -1785,12 +2203,35 @@ session_by_channel(int id) return NULL; } +static Session * +session_by_x11_channel(int id) +{ + int i, j; + + for (i = 0; i < sessions_nalloc; i++) { + Session *s = &sessions[i]; + + if (s->x11_chanids == NULL || !s->used) + continue; + for (j = 0; s->x11_chanids[j] != -1; j++) { + if (s->x11_chanids[j] == id) { + debug("session_by_x11_channel: session %d " + "channel %d", s->self, id); + return s; + } + } + } + debug("session_by_x11_channel: unknown channel %d", id); + session_dump(); + return NULL; +} + static Session * session_by_pid(pid_t pid) { int i; debug("session_by_pid: pid %ld", (long)pid); - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; if (s->used && s->pid == pid) return s; @@ -1826,12 +2267,6 @@ session_pty_req(Session *s) packet_disconnect("Protocol error: you already have a pty."); return 0; } - /* Get the time and hostname when the user last logged in. */ - if (options.print_lastlog) { - s->hostname[0] = '\0'; - s->last_login_time = get_last_login_time(s->pw->pw_uid, - s->pw->pw_name, s->hostname, sizeof(s->hostname)); - } s->term = packet_get_string(&len); @@ -1852,7 +2287,8 @@ session_pty_req(Session *s) /* Allocate a pty and open it. */ debug("Allocating pty."); - if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) { + if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, + sizeof(s->tty)))) { if (s->term) xfree(s->term); s->term = NULL; @@ -1868,11 +2304,6 @@ 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); @@ -1890,30 +2321,33 @@ session_subsystem_req(Session *s) struct stat st; u_int len; int success = 0; - char *cmd, *subsys = packet_get_string(&len); - int i; + char *prog, *cmd, *subsys = packet_get_string(&len); + u_int i; packet_check_eom(); - log("subsystem request for %.100s", subsys); + logit("subsystem request for %.100s", subsys); for (i = 0; i < options.num_subsystems; i++) { if (strcmp(subsys, options.subsystem_name[i]) == 0) { - cmd = options.subsystem_command[i]; - if (stat(cmd, &st) < 0) { - error("subsystem: cannot stat %s: %s", cmd, + prog = options.subsystem_command[i]; + cmd = options.subsystem_args[i]; + if (!strcmp(INTERNAL_SFTP_NAME, prog)) { + s->is_subsystem = SUBSYSTEM_INT_SFTP; + } else if (stat(prog, &st) < 0) { + error("subsystem: cannot stat %s: %s", prog, strerror(errno)); break; + } else { + s->is_subsystem = SUBSYSTEM_EXT; } debug("subsystem: exec() %s", cmd); - s->is_subsystem = 1; - do_exec(s, cmd); - success = 1; + success = do_exec(s, cmd) == 0; break; } } if (!success) - log("subsystem request for %.100s failed, subsystem not found", + logit("subsystem request for %.100s failed, subsystem not found", subsys); xfree(subsys); @@ -1925,6 +2359,11 @@ session_x11_req(Session *s) { int success; + if (s->auth_proto != NULL || s->auth_data != NULL) { + error("session_x11_req: session %d: " + "x11 forwarding already active", s->self); + return 0; + } s->single_connection = packet_get_char(); s->auth_proto = packet_get_string(NULL); s->auth_data = packet_get_string(NULL); @@ -1945,27 +2384,74 @@ static int session_shell_req(Session *s) { packet_check_eom(); - do_exec(s, NULL); - return 1; + return do_exec(s, NULL) == 0; } static int session_exec_req(Session *s) { - u_int len; + u_int len, success; + char *command = packet_get_string(&len); packet_check_eom(); - do_exec(s, command); + success = do_exec(s, command) == 0; xfree(command); + return success; +} + +static int +session_break_req(Session *s) +{ + + packet_get_int(); /* ignored */ + packet_check_eom(); + + if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0) + return 0; return 1; } +static int +session_env_req(Session *s) +{ + char *name, *val; + u_int name_len, val_len, i; + + name = packet_get_string(&name_len); + val = packet_get_string(&val_len); + packet_check_eom(); + + /* Don't set too many environment variables */ + if (s->num_env > 128) { + debug2("Ignoring env request %s: too many env vars", name); + goto fail; + } + + for (i = 0; i < options.num_accept_env; i++) { + if (match_pattern(name, options.accept_env[i])) { + debug2("Setting env %d: %s=%s", s->num_env, name, val); + s->env = xrealloc(s->env, s->num_env + 1, + sizeof(*s->env)); + s->env[s->num_env].name = name; + s->env[s->num_env].val = val; + s->num_env++; + return (1); + } + } + debug2("Ignoring env request %s: disallowed name", name); + + fail: + xfree(name); + xfree(val); + return (0); +} + static int session_auth_agent_req(Session *s) { static int called = 0; packet_check_eom(); - if (no_agent_forwarding_flag) { + if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { debug("session_auth_agent_req: no_agent_forwarding_flag"); return 0; } @@ -1984,7 +2470,7 @@ session_input_channel_req(Channel *c, const char *rtype) Session *s; if ((s = session_by_channel(c->self)) == NULL) { - log("session_input_channel_req: no session %d req %.100s", + logit("session_input_channel_req: no session %d req %.100s", c->self, rtype); return 0; } @@ -2000,23 +2486,28 @@ session_input_channel_req(Channel *c, const char *rtype) } else if (strcmp(rtype, "exec") == 0) { success = session_exec_req(s); } else if (strcmp(rtype, "pty-req") == 0) { - success = session_pty_req(s); + success = session_pty_req(s); } else if (strcmp(rtype, "x11-req") == 0) { success = session_x11_req(s); } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { success = session_auth_agent_req(s); } else if (strcmp(rtype, "subsystem") == 0) { success = session_subsystem_req(s); + } else if (strcmp(rtype, "env") == 0) { + success = session_env_req(s); } } if (strcmp(rtype, "window-change") == 0) { success = session_window_change_req(s); + } else if (strcmp(rtype, "break") == 0) { + success = session_break_req(s); } + return success; } void -session_set_fds(Session *s, int fdin, int fdout, int fderr) +session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty) { if (!compat20) fatal("session_set_fds: called for proto != 2.0"); @@ -2026,11 +2517,16 @@ session_set_fds(Session *s, int fdin, int fdout, int fderr) */ if (s->chanid == -1) fatal("no channel for session %d", s->self); + if (options.hpn_disabled) channel_set_fds(s->chanid, fdout, fdin, fderr, fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, - 1, - CHAN_SES_WINDOW_DEFAULT); + 1, is_tty, CHAN_SES_WINDOW_DEFAULT); + else + channel_set_fds(s->chanid, + fdout, fdin, fderr, + fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, + 1, is_tty, options.hpn_buffer_size); } /* @@ -2038,10 +2534,8 @@ 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; @@ -2064,17 +2558,18 @@ session_pty_cleanup2(void *session) * the pty cleanup, so that another process doesn't get this pty * while we're still cleaning up. */ - if (close(s->ptymaster) < 0) - error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno)); + if (s->ptymaster != -1 && close(s->ptymaster) < 0) + error("close(s->ptymaster/%d): %s", + s->ptymaster, strerror(errno)); /* unlink pty from session */ s->ttyfd = -1; } void -session_pty_cleanup(void *session) +session_pty_cleanup(Session *s) { - PRIVSEP(session_pty_cleanup2(session)); + PRIVSEP(session_pty_cleanup2(s)); } static char * @@ -2098,6 +2593,62 @@ sig2name(int sig) return "SIG@openssh.com"; } +static void +session_close_x11(int id) +{ + Channel *c; + + if ((c = channel_by_id(id)) == NULL) { + debug("session_close_x11: x11 channel %d missing", id); + } else { + /* Detach X11 listener */ + debug("session_close_x11: detach x11 channel %d", id); + channel_cancel_cleanup(id); + if (c->ostate != CHAN_OUTPUT_CLOSED) + chan_mark_dead(c); + } +} + +static void +session_close_single_x11(int id, void *arg) +{ + Session *s; + u_int i; + + debug3("session_close_single_x11: channel %d", id); + channel_cancel_cleanup(id); + if ((s = session_by_x11_channel(id)) == NULL) + fatal("session_close_single_x11: no x11 channel %d", id); + for (i = 0; s->x11_chanids[i] != -1; i++) { + debug("session_close_single_x11: session %d: " + "closing channel %d", s->self, s->x11_chanids[i]); + /* + * The channel "id" is already closing, but make sure we + * close all of its siblings. + */ + if (s->x11_chanids[i] != id) + session_close_x11(s->x11_chanids[i]); + } + xfree(s->x11_chanids); + s->x11_chanids = NULL; + if (s->display) { + xfree(s->display); + s->display = NULL; + } + if (s->auth_proto) { + xfree(s->auth_proto); + s->auth_proto = NULL; + } + if (s->auth_data) { + xfree(s->auth_data); + s->auth_data = NULL; + } + if (s->auth_display) { + xfree(s->auth_display); + s->auth_display = NULL; + } +} + static void session_exit_message(Session *s, int status) { @@ -2117,7 +2668,7 @@ session_exit_message(Session *s, int status) channel_request_start(s->chanid, "exit-signal", 0); packet_put_cstring(sig2name(WTERMSIG(status))); #ifdef WCOREDUMP - packet_put_char(WCOREDUMP(status)); + packet_put_char(WCOREDUMP(status)? 1 : 0); #else /* WCOREDUMP */ packet_put_char(0); #endif /* WCOREDUMP */ @@ -2131,7 +2682,14 @@ session_exit_message(Session *s, int status) /* disconnect channel */ debug("session_exit_message: release channel %d", s->chanid); - channel_cancel_cleanup(s->chanid); + + /* + * Adjust cleanup callback attachment to send close messages when + * the channel gets EOF. The session will be then be closed + * by session_close_by_channel when the childs close their fds. + */ + channel_register_cleanup(c->self, session_close_by_channel, 1); + /* * emulate a write failure with 'chan_write_failed', nobody will be * interested in data we write. @@ -2140,29 +2698,37 @@ session_exit_message(Session *s, int status) */ if (c->ostate != CHAN_OUTPUT_CLOSED) chan_write_failed(c); - s->chanid = -1; } void session_close(Session *s) { + u_int i; + debug("session_close: session %d pid %ld", s->self, (long)s->pid); - if (s->ttyfd != -1) { - fatal_remove_cleanup(session_pty_cleanup, (void *)s); + if (s->ttyfd != -1) session_pty_cleanup(s); - } if (s->term) xfree(s->term); if (s->display) xfree(s->display); + if (s->x11_chanids) + xfree(s->x11_chanids); if (s->auth_display) xfree(s->auth_display); if (s->auth_data) xfree(s->auth_data); if (s->auth_proto) xfree(s->auth_proto); - s->used = 0; + if (s->env != NULL) { + for (i = 0; i < s->num_env; i++) { + xfree(s->env[i].name); + xfree(s->env[i].val); + } + xfree(s->env); + } session_proctitle(s); + session_unused(s->self); } void @@ -2176,7 +2742,9 @@ session_close_by_pid(pid_t pid, int status) } if (s->chanid != -1) session_exit_message(s, status); - session_close(s); + if (s->ttyfd != -1) + session_pty_cleanup(s); + s->pid = 0; } /* @@ -2187,6 +2755,8 @@ void session_close_by_channel(int id, void *arg) { Session *s = session_by_channel(id); + u_int i; + if (s == NULL) { debug("session_close_by_channel: no session for id %d", id); return; @@ -2199,14 +2769,21 @@ session_close_by_channel(int id, void *arg) * delay detach of session, but release pty, since * the fd's to the child are already closed */ - if (s->ttyfd != -1) { - fatal_remove_cleanup(session_pty_cleanup, (void *)s); + if (s->ttyfd != -1) session_pty_cleanup(s); - } return; } /* detach by removing callback */ channel_cancel_cleanup(s->chanid); + + /* Close any X11 listeners associated with this session */ + if (s->x11_chanids != NULL) { + for (i = 0; s->x11_chanids[i] != -1; i++) { + session_close_x11(s->x11_chanids[i]); + s->x11_chanids[i] = -1; + } + } + s->chanid = -1; session_close(s); } @@ -2215,7 +2792,7 @@ void session_destroy_all(void (*closefunc)(Session *)) { int i; - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; if (s->used) { if (closefunc != NULL) @@ -2234,16 +2811,16 @@ session_tty_list(void) char *cp; buf[0] = '\0'; - for (i = 0; i < MAX_SESSIONS; i++) { + for (i = 0; i < sessions_nalloc; i++) { Session *s = &sessions[i]; if (s->used && s->ttyfd != -1) { - + if (strncmp(s->tty, "/dev/", 5) != 0) { cp = strrchr(s->tty, '/'); cp = (cp == NULL) ? s->tty : cp + 1; } else cp = s->tty + 5; - + if (buf[0] != '\0') strlcat(buf, ",", sizeof buf); strlcat(buf, cp, sizeof buf); @@ -2269,6 +2846,7 @@ session_setup_x11fwd(Session *s) struct stat st; char display[512], auth_display[512]; char hostname[MAXHOSTNAMELEN]; + u_int i; if (no_x11_forwarding_flag) { packet_send_debug("X11 forwarding disabled in user configuration file."); @@ -2294,10 +2872,14 @@ session_setup_x11fwd(Session *s) } if (x11_create_display_inet(options.x11_display_offset, options.x11_use_localhost, s->single_connection, - &s->display_number) == -1) { + &s->display_number, &s->x11_chanids) == -1) { debug("x11_create_display_inet failed."); return 0; } + for (i = 0; s->x11_chanids[i] != -1; i++) { + channel_register_cleanup(s->x11_chanids[i], + session_close_single_x11, 0); + } /* Set up a suitable value for the DISPLAY variable. */ if (gethostname(hostname, sizeof(hostname)) < 0) @@ -2343,7 +2925,55 @@ static void do_authenticated2(Authctxt *authctxt) { server_loop2(authctxt); -#if defined(GSSAPI) - ssh_gssapi_cleanup_creds(NULL); +} + +void +do_cleanup(Authctxt *authctxt) +{ + static int called = 0; + + debug("do_cleanup"); + + /* no cleanup if we're in the child for login shell */ + if (is_child) + return; + + /* avoid double cleanup */ + if (called) + return; + called = 1; + + if (authctxt == NULL) + return; + +#ifdef USE_PAM + if (options.use_pam) { + sshpam_cleanup(); + sshpam_thread_cleanup(); + } +#endif + + if (!authctxt->authenticated) + return; + +#ifdef KRB5 + if (options.kerberos_ticket_cleanup && + authctxt->krb5_ctx) + krb5_cleanup_proc(authctxt); #endif + +#ifdef GSSAPI + if (compat20 && options.gss_cleanup_creds) + ssh_gssapi_cleanup_creds(); +#endif + + /* remove agent socket */ + auth_sock_cleanup_proc(authctxt->pw); + + /* + * Cleanup ptys/utmp only if privsep is disabled, + * or if running in monitor. + */ + if (!use_privsep || mm_is_monitor()) + session_destroy_all(session_pty_cleanup2); }