From 666aa9cc1660793c97ef29a6cb66dfbb894dde8f Mon Sep 17 00:00:00 2001 From: des Date: Tue, 22 Jul 2008 18:58:19 +0000 Subject: Revert part of 180714 - the intent was to flatten dist, not to nuke it. --- crypto/openssh/session.c | 2510 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2510 insertions(+) create mode 100644 crypto/openssh/session.c (limited to 'crypto/openssh/session.c') diff --git a/crypto/openssh/session.c b/crypto/openssh/session.c new file mode 100644 index 0000000..69153ad --- /dev/null +++ b/crypto/openssh/session.c @@ -0,0 +1,2510 @@ +/* $OpenBSD: session.c,v 1.220 2006/10/09 23:36:11 djm Exp $ */ +/* + * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland + * All rights reserved + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * SSH2 support by Markus Friedl. + * 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 + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#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 "xmalloc.h" +#include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" +#include "sshpty.h" +#include "packet.h" +#include "buffer.h" +#include "match.h" +#include "uidswap.h" +#include "compat.h" +#include "channels.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" +#include "log.h" +#include "servconf.h" +#include "sshlogin.h" +#include "serverloop.h" +#include "canohost.h" +#include "session.h" +#include "kex.h" +#include "monitor_wrap.h" + +#if defined(KRB5) && defined(USE_AFS) +#include +#endif + +/* func */ + +Session *session_new(void); +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 int session_pty_req(Session *); + +/* import */ +extern ServerOptions options; +extern char *__progname; +extern int log_stderr; +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]; + +#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; + +/* 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); + + /* setup the channel layer */ + if (!no_port_forwarding_flag && options.allow_tcp_forwarding) + channel_permit_all_opens(); + + if (compat20) + do_authenticated2(authctxt); + else + do_authenticated1(authctxt); + + do_cleanup(authctxt); +} + +/* + * Prepares for an interactive session. This is called after the user has + * been successfully authenticated. During this message exchange, pseudo + * terminals are allocated, X11, TCP/IP, and authentication agent forwardings + * are requested, etc. + */ +static void +do_authenticated1(Authctxt *authctxt) +{ + Session *s; + char *command; + 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; + + /* + * We stay in this loop until the client requests to execute a shell + * or a command. + */ + for (;;) { + success = 0; + + /* Get a packet from the client. */ + type = packet_read(); + + /* Process the packet. */ + switch (type) { + case SSH_CMSG_REQUEST_COMPRESSION: + compression_level = packet_get_int(); + packet_check_eom(); + if (compression_level < 1 || compression_level > 9) { + 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. */ + enable_compression_after_reply = 1; + success = 1; + break; + + case SSH_CMSG_REQUEST_PTY: + success = session_pty_req(s); + break; + + case SSH_CMSG_X11_REQUEST_FORWARDING: + s->auth_proto = packet_get_string(&proto_len); + s->auth_data = packet_get_string(&data_len); + + screen_flag = packet_get_protocol_flags() & + SSH_PROTOFLAG_SCREEN_NUMBER; + debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag); + + if (packet_remaining() == 4) { + if (!screen_flag) + debug2("Buggy client: " + "X11 screen flag missing"); + s->screen = packet_get_int(); + } else { + s->screen = 0; + } + packet_check_eom(); + success = session_setup_x11fwd(s); + if (!success) { + xfree(s->auth_proto); + xfree(s->auth_data); + s->auth_proto = NULL; + s->auth_data = NULL; + } + break; + + case SSH_CMSG_AGENT_REQUEST_FORWARDING: + if (no_agent_forwarding_flag || compat13) { + debug("Authentication agent forwarding not permitted for this authentication."); + break; + } + debug("Received authentication agent forwarding request."); + success = auth_input_request_forwarding(s->pw); + break; + + case SSH_CMSG_PORT_FORWARD_REQUEST: + if (no_port_forwarding_flag) { + debug("Port forwarding not permitted for this authentication."); + break; + } + if (!options.allow_tcp_forwarding) { + debug("Port forwarding not permitted."); + break; + } + debug("Received TCP/IP port forwarding request."); + if (channel_input_port_forward_request(s->pw->pw_uid == 0, + options.gateway_ports) < 0) { + debug("Port forwarding failed."); + break; + } + success = 1; + break; + + case SSH_CMSG_MAX_PACKET_SIZE: + if (packet_set_maxsize(packet_get_int()) > 0) + success = 1; + break; + + 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); + xfree(command); + } else { + do_exec(s, NULL); + } + packet_check_eom(); + session_close(s); + return; + + default: + /* + * Any unknown messages in this phase are ignored, + * and a failure message is returned. + */ + logit("Unknown packet type received after authentication: %d", type); + } + packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + + /* Enable compression now that we have replied if appropriate. */ + if (enable_compression_after_reply) { + enable_compression_after_reply = 0; + packet_start_compression(compression_level); + } + } +} + +/* + * 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 +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 */ + 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 (s == NULL) + fatal("do_exec_no_pty: no session"); + + session_proctitle(s); + +#if defined(USE_PAM) + 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); + + /* + * Create a new session and process group since the 4.4BSD + * setlogin() affects the entire process group. + */ + if (setsid() < 0) + error("setsid failed: %.100s", strerror(errno)); + +#ifdef USE_PIPES + /* + * Redirect stdin. We close the parent side of the socket + * pair, and make the child side the standard input. + */ + close(pin[1]); + if (dup2(pin[0], 0) < 0) + perror("dup2 stdin"); + close(pin[0]); + + /* Redirect stdout. */ + close(pout[0]); + if (dup2(pout[1], 1) < 0) + perror("dup2 stdout"); + close(pout[1]); + + /* Redirect stderr. */ + close(perr[0]); + if (dup2(perr[1], 2) < 0) + perror("dup2 stderr"); + close(perr[1]); +#else /* USE_PIPES */ + /* + * Redirect stdin, stdout, and stderr. Stdin and stdout will + * use the same socket, as some programs (particularly rdist) + * seem to depend on it. + */ + close(inout[1]); + 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. */ + perror("dup2 stdout"); + if (dup2(err[0], 2) < 0) /* stderr */ + 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); +#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); +#ifdef USE_PIPES + /* We are the parent. Close the child sides of the pipes. */ + close(pin[0]); + close(pout[1]); + close(perr[1]); + + if (compat20) { + 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]); + /* server_loop has closed pin[1], pout[0], and perr[0]. */ + } +#else /* USE_PIPES */ + /* We are the parent. Close the child sides of the socket pairs. */ + 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. + */ + if (compat20) { + session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]); + } else { + server_loop(pid, inout[1], inout[1], err[1]); + /* server_loop has closed inout[1] and err[1]. */ + } +#endif /* USE_PIPES */ +} + +/* + * This is called to fork and execute a command when we have a tty. This + * will call do_child from the child, and server_loop from the parent after + * setting up file descriptors, controlling tty, updating wtmp, utmp, + * lastlog, and other such operations. + */ +void +do_exec_pty(Session *s, const char *command) +{ + int fdout, ptyfd, ttyfd, ptymaster; + pid_t pid; + + if (s == NULL) + fatal("do_exec_pty: no session"); + ptyfd = s->ptyfd; + ttyfd = s->ttyfd; + +#if defined(USE_PAM) + 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/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)) { +#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); +# endif +#endif + + /* Do common processing for the child, such as execing the 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); +#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. */ + packet_set_interactive(1); + if (compat20) { + session_set_fds(s, ptyfd, fdout, -1); + } else { + server_loop(pid, ptyfd, fdout, -1); + /* server_loop _has_ closed ptyfd and fdout. */ + } +} + +#ifdef LOGIN_NEEDS_UTMPX +static void +do_pre_login(Session *s) +{ + socklen_t fromlen; + struct sockaddr_storage from; + pid_t pid = getpid(); + + /* + * Get IP address of client. If the connection is not a socket, let + * the address be 0.0.0.0. + */ + memset(&from, 0, sizeof(from)); + fromlen = sizeof(from); + if (packet_connection_is_on_socket()) { + if (getpeername(packet_get_connection_in(), + (struct sockaddr *)&from, &fromlen) < 0) { + debug("getpeername: %.100s", strerror(errno)); + cleanup_exit(255); + } + } + + record_utmp_only(pid, s->tty, s->pw->pw_name, + get_remote_name_or_ip(utmp_len, options.use_dns), + (struct sockaddr *)&from, fromlen); +} +#endif + +/* + * This is called to fork and execute a command. If another command is + * to be forced, execute that instead. + */ +void +do_exec(Session *s, const char *command) +{ + if (options.adm_forced_command) { + original_command = command; + command = options.adm_forced_command; + debug("Forced command (config) '%.900s'", command); + } else if (forced_command) { + original_command = command; + command = forced_command; + debug("Forced command (key option) '%.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; + + /* + * 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) +{ + socklen_t fromlen; + struct sockaddr_storage from; + struct passwd * pw = s->pw; + pid_t pid = getpid(); + + /* + * Get IP address of client. If the connection is not a socket, let + * the address be 0.0.0.0. + */ + memset(&from, 0, sizeof(from)); + fromlen = sizeof(from); + if (packet_connection_is_on_socket()) { + if (getpeername(packet_get_connection_in(), + (struct sockaddr *) & from, &fromlen) < 0) { + debug("getpeername: %.100s", strerror(errno)); + cleanup_exit(255); + } + } + + /* Record that there was a login on that tty from the remote host. */ + 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 (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; + + display_loginmsg(); + + do_motd(); +} + +/* + * Display the message of the day. + */ +void +do_motd(void) +{ + FILE *f; + char buf[256]; + + if (options.print_motd) { +#ifdef HAVE_LOGIN_CAP + f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", + "/etc/motd"), "r"); +#else + f = fopen("/etc/motd", "r"); +#endif + if (f) { + while (fgets(buf, sizeof(buf), f)) + fputs(buf, stdout); + fclose(f); + } + } +} + + +/* + * 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. + */ +void +child_set_env(char ***envp, u_int *envsizep, const char *name, + const char *value) +{ + 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 + * already exists, we reuse the slot; otherwise we append a new slot + * at the end of the array, expanding if necessary. + */ + env = *envp; + namelen = strlen(name); + for (i = 0; env[i]; i++) + if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') + break; + if (env[i]) { + /* Reuse the slot. */ + xfree(env[i]); + } else { + /* New variable. Expand if necessary. */ + 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; + } + + /* Allocate space and format the variable in the appropriate slot. */ + env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); + snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); +} + +/* + * Reads environment variables from the given file and adds/overrides them + * into the environment. If the file does not exist, this does nothing. + * Otherwise, it must consist of empty lines, comments (line starts with '#') + * and assignments of the form name=value. No other forms are allowed. + */ +static void +read_environment_file(char ***env, u_int *envsize, + 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') + continue; + if (strchr(cp, '\n')) + *strchr(cp, '\n') = '\0'; + value = strchr(cp, '='); + if (value == NULL) { + fprintf(stderr, "Bad line %u in %.100s\n", lineno, + filename); + continue; + } + /* + * Replace the equals sign by nul, and advance value to + * the value string. + */ + *value = '\0'; + value++; + child_set_env(env, envsize, cp, value); + } + 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; + int i; + + if (source == NULL) + return; + + 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); + child_set_env(env, envsize, var_name, var_val); + + xfree(var_name); + } +} + +static char ** +do_setup_env(Session *s, const char *shell) +{ + char buf[256]; + 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 = xcalloc(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. + */ + { + 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 + * the childs environment as they see fit + */ + ssh_gssapi_do_child(&env, &envsize); +#endif + + if (!options.use_login) { + /* Set basic environment. */ + for (i = 0; i < s->num_env; i++) + child_set_env(&env, &envsize, s->env[i].name, + s->env[i].val); + + child_set_env(&env, &envsize, "USER", pw->pw_name); + child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); +#ifdef _AIX + child_set_env(&env, &envsize, "LOGIN", pw->pw_name); +#endif + child_set_env(&env, &envsize, "HOME", pw->pw_dir); +#ifdef HAVE_LOGIN_CAP + if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) + 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 */ + + 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. */ + if (!options.use_login) { + 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); + } + } + + /* SSH_CLIENT deprecated */ + snprintf(buf, sizeof buf, "%.50s %d %d", + 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) + child_set_env(&env, &envsize, "TERM", s->term); + if (s->display) + child_set_env(&env, &envsize, "DISPLAY", s->display); + if (original_command) + child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", + original_command); + +#ifdef _UNICOS + if (cray_tmpdir[0] != '\0') + 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); + 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. + */ + 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_sock_name != NULL) + child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, + auth_sock_name); + + /* read $HOME/.ssh/environment. */ + if (options.permit_user_env && !options.use_login) { + snprintf(buf, sizeof buf, "%.200s/.ssh/environment", + strcmp(pw->pw_dir, "/") ? pw->pw_dir : ""); + read_environment_file(&env, &envsize, buf); + } + if (debug_flag) { + /* dump the environment */ + fprintf(stderr, "Environment:\n"); + for (i = 0; env[i]; i++) + fprintf(stderr, " %.200s\n", env[i]); + } + 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); + +#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 +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 { + 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. + */ +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 */ + /* When PAM is enabled we rely on it to do the nologin check */ + if (!options.use_pam) + do_nologin(pw); + do_setusercontext(pw); + /* + * PAM session modules in do_setusercontext may have + * generated messages, so if this in an interactive + * login then display them too. + */ + if (!check_quietlogin(s, command)) + display_loginmsg(); +#endif /* HAVE_OSF_SIA */ + } + +#ifdef USE_PAM + if (options.use_pam && !options.use_login && !is_pam_session_open()) { + debug3("PAM session not opened, exiting"); + display_loginmsg(); + exit(254); + } +#endif + + /* + * Get the shell from the password data. An empty shell field is + * legal, and means /bin/sh. + */ + shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; + + /* + * Make sure $SHELL points to the shell from the password file, + * even if shell is overridden from login.conf + */ + env = do_setup_env(s, shell); + +#ifdef HAVE_LOGIN_CAP + shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); +#endif + + /* 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); + /* + * 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) + /* + * 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.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) { + char argv0[256]; + + /* Start the shell. Set initial character to '-'. */ + argv0[0] = '-'; + + if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) + >= sizeof(argv0) - 1) { + errno = EINVAL; + perror(shell); + exit(1); + } + + /* Execute the shell. */ + argv[0] = argv0; + argv[1] = NULL; + execve(shell, argv, env); + + /* 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 *) shell0; + argv[1] = "-c"; + argv[2] = (char *) command; + argv[3] = NULL; + execve(shell, argv, env); + perror(shell); + exit(1); +} + +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; + } + did_init = 1; + } + 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; + s->x11_chanids = NULL; + debug("session_new: session %d", i); + return s; + } + } + return NULL; +} + +static void +session_dump(void) +{ + int i; + for (i = 0; i < MAX_SESSIONS; i++) { + Session *s = &sessions[i]; + debug("dump: used %d session %d %p channel %d pid %ld", + s->used, + s->self, + s, + s->chanid, + (long)s->pid); + } +} + +int +session_open(Authctxt *authctxt, int chanid) +{ + Session *s = session_new(); + debug("session_open: channel %d", chanid); + if (s == NULL) { + error("no more sessions"); + return 0; + } + 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++) { + Session *s = &sessions[i]; + if (s->used && s->chanid == id) { + debug("session_by_channel: session %d channel %d", i, id); + return s; + } + } + debug("session_by_channel: unknown channel %d", id); + session_dump(); + 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 %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 %ld", (long)pid); + session_dump(); + return NULL; +} + +static int +session_window_change_req(Session *s) +{ + s->col = packet_get_int(); + s->row = packet_get_int(); + s->xpixel = packet_get_int(); + s->ypixel = packet_get_int(); + packet_check_eom(); + pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); + return 1; +} + +static int +session_pty_req(Session *s) +{ + u_int len; + int n_bytes; + + if (no_pty_flag) { + debug("Allocating a pty not permitted for this authentication."); + return 0; + } + if (s->ttyfd != -1) { + packet_disconnect("Protocol error: you already have a pty."); + return 0; + } + + s->term = packet_get_string(&len); + + if (compat20) { + s->col = packet_get_int(); + s->row = packet_get_int(); + } else { + s->row = packet_get_int(); + s->col = packet_get_int(); + } + s->xpixel = packet_get_int(); + s->ypixel = packet_get_int(); + + if (strcmp(s->term, "") == 0) { + xfree(s->term); + s->term = NULL; + } + + /* Allocate a pty and open it. */ + debug("Allocating pty."); + if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) { + if (s->term) + xfree(s->term); + s->term = NULL; + s->ptyfd = -1; + s->ttyfd = -1; + error("session_pty_req: session %d alloc failed", s->self); + return 0; + } + debug("session_pty_req: session %d alloc %s", s->self, s->tty); + + /* for SSH1 the tty modes length is not given */ + if (!compat20) + n_bytes = packet_remaining(); + tty_parse_modes(s->ttyfd, &n_bytes); + + 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_check_eom(); + session_proctitle(s); + return 1; +} + +static int +session_subsystem_req(Session *s) +{ + struct stat st; + u_int len; + int success = 0; + char *prog, *cmd, *subsys = packet_get_string(&len); + u_int i; + + 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) { + prog = options.subsystem_command[i]; + cmd = options.subsystem_args[i]; + if (stat(prog, &st) < 0) { + error("subsystem: cannot stat %s: %s", prog, + strerror(errno)); + break; + } + debug("subsystem: exec() %s", cmd); + s->is_subsystem = 1; + do_exec(s, cmd); + success = 1; + break; + } + } + + if (!success) + logit("subsystem request for %.100s failed, subsystem not found", + subsys); + + xfree(subsys); + return success; +} + +static int +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); + s->screen = packet_get_int(); + packet_check_eom(); + + success = session_setup_x11fwd(s); + if (!success) { + xfree(s->auth_proto); + xfree(s->auth_data); + s->auth_proto = NULL; + s->auth_data = NULL; + } + return success; +} + +static int +session_shell_req(Session *s) +{ + packet_check_eom(); + do_exec(s, NULL); + return 1; +} + +static int +session_exec_req(Session *s) +{ + u_int len; + char *command = packet_get_string(&len); + 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, 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) { + debug("session_auth_agent_req: no_agent_forwarding_flag"); + return 0; + } + if (called) { + return 0; + } else { + called = 1; + return auth_input_request_forwarding(s->pw); + } +} + +int +session_input_channel_req(Channel *c, const char *rtype) +{ + int success = 0; + Session *s; + + 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 + * or a subsystem is executed + */ + if (c->type == SSH_CHANNEL_LARVAL) { + if (strcmp(rtype, "shell") == 0) { + success = session_shell_req(s); + } else if (strcmp(rtype, "exec") == 0) { + success = session_exec_req(s); + } else if (strcmp(rtype, "pty-req") == 0) { + 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) +{ + if (!compat20) + fatal("session_set_fds: called for proto != 2.0"); + /* + * now that have a child and a pipe to the child, + * we can activate our channel and register the fd's + */ + if (s->chanid == -1) + fatal("no channel for session %d", s->self); + channel_set_fds(s->chanid, + fdout, fdin, fderr, + fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, + 1, + CHAN_SES_WINDOW_DEFAULT); +} + +/* + * Function to perform pty cleanup. Also called if we get aborted abnormally + * (e.g., due to a dropped connection). + */ +void +session_pty_cleanup2(Session *s) +{ + if (s == NULL) { + error("session_pty_cleanup: no session"); + return; + } + if (s->ttyfd == -1) + return; + + debug("session_pty_cleanup: session %d release %s", s->self, s->tty); + + /* Record that the user has logged out. */ + if (s->pid != 0) + record_logout(s->pid, s->tty, s->pw->pw_name); + + /* Release the pseudo-tty. */ + if (getuid() == 0) + pty_release(s->tty); + + /* + * Close the server side of the socket pairs. We must do this after + * 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)); + + /* 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_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) +{ + Channel *c; + + 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 %ld", + s->self, s->chanid, (long)s->pid); + + if (WIFEXITED(status)) { + 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_cstring(sig2name(WTERMSIG(status))); +#ifdef WCOREDUMP + packet_put_char(WCOREDUMP(status)); +#else /* WCOREDUMP */ + packet_put_char(0); +#endif /* WCOREDUMP */ + packet_put_cstring(""); + packet_put_cstring(""); + packet_send(); + } else { + /* Some weird exit cause. Just exit. */ + packet_disconnect("wait returned status %04x.", status); + } + + /* disconnect channel */ + debug("session_exit_message: release channel %d", 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. + * Note that we must not call 'chan_read_failed', since there could + * be some more data waiting in the pipe. + */ + if (c->ostate != CHAN_OUTPUT_CLOSED) + chan_write_failed(c); +} + +void +session_close(Session *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; + 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); +} + +void +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 %ld", + (long)pid); + return; + } + if (s->chanid != -1) + session_exit_message(s, status); + if (s->ttyfd != -1) + session_pty_cleanup(s); + s->pid = 0; +} + +/* + * this is called when a channel dies before + * the session 'child' itself dies + */ +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; + } + 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); + + /* 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); +} + +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); + } + } +} + +static char * +session_tty_list(void) +{ + static char buf[1024]; + int i; + char *cp; + + buf[0] = '\0'; + 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); + } + } + if (buf[0] == '\0') + strlcpy(buf, "notty", sizeof buf); + return buf; +} + +void +session_proctitle(Session *s) +{ + if (s->pw == NULL) + error("no user for session %d", s->self); + else + setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); +} + +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."); + return 0; + } + if (!options.x11_forwarding) { + debug("X11 forwarding disabled in server configuration file."); + return 0; + } + if (!options.xauth_location || + (stat(options.xauth_location, &st) == -1)) { + packet_send_debug("No xauth program; cannot forward with spoofing."); + return 0; + } + if (options.use_login) { + packet_send_debug("X11 forwarding disabled; " + "not compatible with UseLogin=yes."); + return 0; + } + if (s->display != NULL) { + debug("X11 display already set."); + return 0; + } + 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, 0); + } + + /* 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(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 || !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 + +#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); +} -- cgit v1.1