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Diffstat (limited to '')
| -rw-r--r-- | session.c | 2732 |
1 files changed, 2732 insertions, 0 deletions
diff --git a/session.c b/session.c new file mode 100644 index 0000000..aa342e8 --- /dev/null +++ b/session.c @@ -0,0 +1,2732 @@ +/* $OpenBSD: session.c,v 1.336 2023/08/10 23:05:48 djm Exp $ */ +/* + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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 <sys/types.h> +#ifdef HAVE_SYS_STAT_H +# include <sys/stat.h> +#endif +#include <sys/socket.h> +#include <sys/un.h> +#include <sys/wait.h> + +#include <arpa/inet.h> + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <grp.h> +#include <netdb.h> +#ifdef HAVE_PATHS_H +#include <paths.h> +#endif +#include <pwd.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <stdarg.h> +#include <unistd.h> +#include <limits.h> + +#include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" +#include "ssh.h" +#include "ssh2.h" +#include "sshpty.h" +#include "packet.h" +#include "sshbuf.h" +#include "ssherr.h" +#include "match.h" +#include "uidswap.h" +#include "channels.h" +#include "sshkey.h" +#include "cipher.h" +#ifdef GSSAPI +#include "ssh-gss.h" +#endif +#include "hostfile.h" +#include "auth.h" +#include "auth-options.h" +#include "authfd.h" +#include "pathnames.h" +#include "log.h" +#include "misc.h" +#include "servconf.h" +#include "sshlogin.h" +#include "serverloop.h" +#include "canohost.h" +#include "session.h" +#include "kex.h" +#include "monitor_wrap.h" +#include "sftp.h" +#include "atomicio.h" + +#if defined(KRB5) && defined(USE_AFS) +#include <kafs.h> +#endif + +#ifdef WITH_SELINUX +#include <selinux/selinux.h> +#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(struct ssh *, Session *, int, int, int, int, int); +void session_pty_cleanup(Session *); +void session_proctitle(Session *); +int session_setup_x11fwd(struct ssh *, Session *); +int do_exec_pty(struct ssh *, Session *, const char *); +int do_exec_no_pty(struct ssh *, Session *, const char *); +int do_exec(struct ssh *, Session *, const char *); +void do_login(struct ssh *, Session *, const char *); +void do_child(struct ssh *, Session *, const char *); +void do_motd(void); +int check_quietlogin(Session *, const char *); + +static void do_authenticated2(struct ssh *, Authctxt *); + +static int session_pty_req(struct ssh *, Session *); + +/* import */ +extern ServerOptions options; +extern char *__progname; +extern int debug_flag; +extern u_int utmp_len; +extern int startup_pipe; +extern void destroy_sensitive_data(void); +extern struct sshbuf *loginmsg; +extern struct sshauthopt *auth_opts; +extern char *tun_fwd_ifnames; /* serverloop.c */ + +/* original command from peer. */ +const char *original_command = NULL; + +/* data */ +static int sessions_first_unused = -1; +static int sessions_nalloc = 0; +static Session *sessions = NULL; + +#define SUBSYSTEM_NONE 0 +#define SUBSYSTEM_EXT 1 +#define SUBSYSTEM_INT_SFTP 2 +#define SUBSYSTEM_INT_SFTP_ERROR 3 + +#ifdef HAVE_LOGIN_CAP +login_cap_t *lc; +#endif + +static int is_child = 0; +static int in_chroot = 0; + +/* File containing userauth info, if ExposeAuthInfo set */ +static char *auth_info_file = NULL; + +/* 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 ssh *ssh, struct passwd * pw) +{ + Channel *nc; + int sock = -1; + + 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_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); + + /* Create private directory for socket */ + if (mkdtemp(auth_sock_dir) == NULL) { + ssh_packet_send_debug(ssh, "Agent forwarding disabled: " + "mkdtemp() failed: %.100s", strerror(errno)); + restore_uid(); + free(auth_sock_dir); + auth_sock_dir = NULL; + goto authsock_err; + } + + xasprintf(&auth_sock_name, "%s/agent.%ld", + auth_sock_dir, (long) getpid()); + + /* Start a Unix listener on auth_sock_name. */ + sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); + + /* Restore the privileged uid. */ + restore_uid(); + + /* Check for socket/bind/listen failure. */ + if (sock < 0) + goto authsock_err; + + /* Allocate a channel for the authentication agent socket. */ + nc = channel_new(ssh, "auth-listener", + SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, + CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, + 0, "auth socket", 1); + nc->path = xstrdup(auth_sock_name); + return 1; + + authsock_err: + free(auth_sock_name); + if (auth_sock_dir != NULL) { + temporarily_use_uid(pw); + rmdir(auth_sock_dir); + restore_uid(); + free(auth_sock_dir); + } + if (sock != -1) + close(sock); + auth_sock_name = NULL; + auth_sock_dir = NULL; + return 0; +} + +static void +display_loginmsg(void) +{ + int r; + + if (sshbuf_len(loginmsg) == 0) + return; + if ((r = sshbuf_put_u8(loginmsg, 0)) != 0) + fatal_fr(r, "sshbuf_put_u8"); + printf("%s", (char *)sshbuf_ptr(loginmsg)); + sshbuf_reset(loginmsg); +} + +static void +prepare_auth_info_file(struct passwd *pw, struct sshbuf *info) +{ + int fd = -1, success = 0; + + if (!options.expose_userauth_info || info == NULL) + return; + + temporarily_use_uid(pw); + auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX"); + if ((fd = mkstemp(auth_info_file)) == -1) { + error_f("mkstemp: %s", strerror(errno)); + goto out; + } + if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info), + sshbuf_len(info)) != sshbuf_len(info)) { + error_f("write: %s", strerror(errno)); + goto out; + } + if (close(fd) != 0) { + error_f("close: %s", strerror(errno)); + goto out; + } + success = 1; + out: + if (!success) { + if (fd != -1) + close(fd); + free(auth_info_file); + auth_info_file = NULL; + } + restore_uid(); +} + +static void +set_fwdpermit_from_authopts(struct ssh *ssh, const struct sshauthopt *opts) +{ + char *tmp, *cp, *host; + int port; + size_t i; + + if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0) { + channel_clear_permission(ssh, FORWARD_USER, FORWARD_LOCAL); + for (i = 0; i < auth_opts->npermitopen; i++) { + tmp = cp = xstrdup(auth_opts->permitopen[i]); + /* This shouldn't fail as it has already been checked */ + if ((host = hpdelim2(&cp, NULL)) == NULL) + fatal_f("internal error: hpdelim"); + host = cleanhostname(host); + if (cp == NULL || (port = permitopen_port(cp)) < 0) + fatal_f("internal error: permitopen port"); + channel_add_permission(ssh, + FORWARD_USER, FORWARD_LOCAL, host, port); + free(tmp); + } + } + if ((options.allow_tcp_forwarding & FORWARD_REMOTE) != 0) { + channel_clear_permission(ssh, FORWARD_USER, FORWARD_REMOTE); + for (i = 0; i < auth_opts->npermitlisten; i++) { + tmp = cp = xstrdup(auth_opts->permitlisten[i]); + /* This shouldn't fail as it has already been checked */ + if ((host = hpdelim(&cp)) == NULL) + fatal_f("internal error: hpdelim"); + host = cleanhostname(host); + if (cp == NULL || (port = permitopen_port(cp)) < 0) + fatal_f("internal error: permitlisten port"); + channel_add_permission(ssh, + FORWARD_USER, FORWARD_REMOTE, host, port); + free(tmp); + } + } +} + +void +do_authenticated(struct ssh *ssh, Authctxt *authctxt) +{ + setproctitle("%s", authctxt->pw->pw_name); + + auth_log_authopts("active", auth_opts, 0); + + /* setup the channel layer */ + /* XXX - streamlocal? */ + set_fwdpermit_from_authopts(ssh, auth_opts); + + if (!auth_opts->permit_port_forwarding_flag || + options.disable_forwarding) { + channel_disable_admin(ssh, FORWARD_LOCAL); + channel_disable_admin(ssh, FORWARD_REMOTE); + } else { + if ((options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) + channel_disable_admin(ssh, FORWARD_LOCAL); + else + channel_permit_all(ssh, FORWARD_LOCAL); + if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0) + channel_disable_admin(ssh, FORWARD_REMOTE); + else + channel_permit_all(ssh, FORWARD_REMOTE); + } + auth_debug_send(ssh); + + prepare_auth_info_file(authctxt->pw, authctxt->session_info); + + do_authenticated2(ssh, authctxt); + + do_cleanup(ssh, authctxt); +} + +/* Check untrusted xauth strings for metacharacters */ +static int +xauth_valid_string(const char *s) +{ + size_t i; + + for (i = 0; s[i] != '\0'; i++) { + if (!isalnum((u_char)s[i]) && + s[i] != '.' && s[i] != ':' && s[i] != '/' && + s[i] != '-' && s[i] != '_') + return 0; + } + return 1; +} + +#define USE_PIPES 1 +/* + * 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. + */ +int +do_exec_no_pty(struct ssh *ssh, Session *s, const char *command) +{ + pid_t pid; +#ifdef USE_PIPES + int pin[2], pout[2], perr[2]; + + if (s == NULL) + fatal("do_exec_no_pty: no session"); + + /* Allocate pipes for communicating with the program. */ + if (pipe(pin) == -1) { + error_f("pipe in: %.100s", strerror(errno)); + return -1; + } + if (pipe(pout) == -1) { + error_f("pipe out: %.100s", strerror(errno)); + close(pin[0]); + close(pin[1]); + return -1; + } + if (pipe(perr) == -1) { + error_f("pipe err: %.100s", strerror(errno)); + close(pin[0]); + close(pin[1]); + close(pout[0]); + close(pout[1]); + return -1; + } +#else + int inout[2], err[2]; + + if (s == NULL) + fatal("do_exec_no_pty: no session"); + + /* Uses socket pairs to communicate with the program. */ + if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) == -1) { + error_f("socketpair #1: %.100s", strerror(errno)); + return -1; + } + if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) == -1) { + error_f("socketpair #2: %.100s", strerror(errno)); + close(inout[0]); + close(inout[1]); + return -1; + } +#endif + + session_proctitle(s); + + /* Fork the child. */ + switch ((pid = fork())) { + case -1: + error_f("fork: %.100s", 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; + + /* + * Create a new session and process group since the 4.4BSD + * setlogin() affects the entire process group. + */ + if (setsid() == -1) + 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) == -1) + perror("dup2 stdin"); + close(pin[0]); + + /* Redirect stdout. */ + close(pout[0]); + if (dup2(pout[1], 1) == -1) + perror("dup2 stdout"); + close(pout[1]); + + /* Redirect stderr. */ + close(perr[0]); + if (dup2(perr[1], 2) == -1) + perror("dup2 stderr"); + close(perr[1]); +#else + /* + * 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) == -1) /* stdin */ + perror("dup2 stdin"); + if (dup2(inout[0], 1) == -1) /* stdout (same as stdin) */ + perror("dup2 stdout"); + close(inout[0]); + if (dup2(err[0], 2) == -1) /* stderr */ + perror("dup2 stderr"); + close(err[0]); +#endif + + /* Do processing for the child (exec command etc). */ + do_child(ssh, s, command); + /* NOTREACHED */ + default: + break; + } + +#ifdef HAVE_CYGWIN + cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); +#endif + + s->pid = pid; + /* Set interactive/non-interactive mode. */ + ssh_packet_set_interactive(ssh, s->display != NULL, + options.ip_qos_interactive, options.ip_qos_bulk); + + /* + * 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. + */ + sshbuf_reset(loginmsg); + +#ifdef USE_PIPES + /* We are the parent. Close the child sides of the pipes. */ + close(pin[0]); + close(pout[1]); + close(perr[1]); + + session_set_fds(ssh, s, pin[1], pout[0], perr[0], + s->is_subsystem, 0); +#else + /* We are the parent. Close the child sides of the socket pairs. */ + close(inout[0]); + close(err[0]); + + /* + * Enter the interactive session. Note: server_loop must be able to + * handle the case that fdin and fdout are the same. + */ + session_set_fds(ssh, s, inout[1], inout[1], err[1], + s->is_subsystem, 0); +#endif + return 0; +} + +/* + * 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. + */ +int +do_exec_pty(struct ssh *ssh, 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; + + /* + * 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)) == -1) { + error_f("dup #1: %s", strerror(errno)); + close(ttyfd); + close(ptyfd); + return -1; + } + /* we keep a reference to the pty master */ + if ((ptymaster = dup(ptyfd)) == -1) { + error_f("dup #2: %s", strerror(errno)); + close(ttyfd); + close(ptyfd); + close(fdout); + return -1; + } + + /* Fork the child. */ + switch ((pid = fork())) { + case -1: + error_f("fork: %.100s", strerror(errno)); + close(fdout); + close(ptymaster); + close(ttyfd); + close(ptyfd); + return -1; + case 0: + is_child = 1; + + close(fdout); + close(ptymaster); + + /* 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) == -1) + error("dup2 stdin: %s", strerror(errno)); + if (dup2(ttyfd, 1) == -1) + error("dup2 stdout: %s", strerror(errno)); + if (dup2(ttyfd, 2) == -1) + 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 + do_login(ssh, s, command); +#endif + /* + * Do common processing for the child, such as execing + * the command. + */ + do_child(ssh, s, command); + /* NOTREACHED */ + default: + break; + } + +#ifdef HAVE_CYGWIN + cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); +#endif + + s->pid = pid; + + /* Parent. Close the slave side of the pseudo tty. */ + close(ttyfd); + + /* Enter interactive session. */ + s->ptymaster = ptymaster; + ssh_packet_set_interactive(ssh, 1, + options.ip_qos_interactive, options.ip_qos_bulk); + session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1); + return 0; +} + +/* + * This is called to fork and execute a command. If another command is + * to be forced, execute that instead. + */ +int +do_exec(struct ssh *ssh, Session *s, const char *command) +{ + int ret; + const char *forced = NULL, *tty = NULL; + char session_type[1024]; + + if (options.adm_forced_command) { + original_command = command; + command = options.adm_forced_command; + forced = "(config)"; + } else if (auth_opts->force_command != NULL) { + original_command = command; + command = auth_opts->force_command; + forced = "(key-option)"; + } + s->forced = 0; + if (forced != NULL) { + s->forced = 1; + if (IS_INTERNAL_SFTP(command)) { + s->is_subsystem = s->is_subsystem ? + SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; + } else if (s->is_subsystem) + s->is_subsystem = SUBSYSTEM_EXT; + snprintf(session_type, sizeof(session_type), + "forced-command %s '%.900s'", forced, command); + } else if (s->is_subsystem) { + snprintf(session_type, sizeof(session_type), + "subsystem '%.900s'", s->subsys); + } else if (command == NULL) { + snprintf(session_type, sizeof(session_type), "shell"); + } else { + /* NB. we don't log unforced commands to preserve privacy */ + snprintf(session_type, sizeof(session_type), "command"); + } + + if (s->ttyfd != -1) { + tty = s->tty; + if (strncmp(tty, "/dev/", 5) == 0) + tty += 5; + } + + verbose("Starting session: %s%s%s for %s from %.200s port %d id %d", + session_type, + tty == NULL ? "" : " on ", + tty == NULL ? "" : tty, + s->pw->pw_name, + ssh_remote_ipaddr(ssh), + ssh_remote_port(ssh), + s->self); + +#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) + ret = do_exec_pty(ssh, s, command); + else + ret = do_exec_no_pty(ssh, 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. + */ + sshbuf_reset(loginmsg); + + return ret; +} + +/* administrative, login(1)-like work */ +void +do_login(struct ssh *ssh, 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 (ssh_packet_connection_is_on_socket(ssh)) { + if (getpeername(ssh_packet_get_connection_in(ssh), + (struct sockaddr *)&from, &fromlen) == -1) { + 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, + session_get_remote_name_or_ip(ssh, 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; +} + +/* + * 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. + * If allowlist is not NULL, then it is interpreted as a pattern list and + * only variable names that match it will be accepted. + */ +static void +read_environment_file(char ***env, u_int *envsize, + const char *filename, const char *allowlist) +{ + FILE *f; + char *line = NULL, *cp, *value; + size_t linesize = 0; + u_int lineno = 0; + + f = fopen(filename, "r"); + if (!f) + return; + + while (getline(&line, &linesize, f) != -1) { + if (++lineno > 1000) + fatal("Too many lines in environment file %s", filename); + for (cp = line; *cp == ' ' || *cp == '\t'; cp++) + ; + if (!*cp || *cp == '#' || *cp == '\n') + continue; + + cp[strcspn(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++; + if (allowlist != NULL && + match_pattern_list(cp, allowlist, 0) != 1) + continue; + child_set_env(env, envsize, cp, value); + } + free(line); + 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", + options.permit_user_env_allowlist); + + 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++) + free(tmpenv[i]); + free(tmpenv); +} +#endif /* HAVE_ETC_DEFAULT_LOGIN */ + +#if defined(USE_PAM) || defined(HAVE_CYGWIN) +static void +copy_environment_denylist(char **source, char ***env, u_int *envsize, + const char *denylist) +{ + 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) { + free(var_name); + continue; + } + *var_val++ = '\0'; + + if (denylist == NULL || + match_pattern_list(var_name, denylist, 0) != 1) { + debug3("Copy environment: %s=%s", var_name, var_val); + child_set_env(env, envsize, var_name, var_val); + } + + free(var_name); + } +} +#endif /* defined(USE_PAM) || defined(HAVE_CYGWIN) */ + +#ifdef HAVE_CYGWIN +static void +copy_environment(char **source, char ***env, u_int *envsize) +{ + copy_environment_denylist(source, env, envsize, NULL); +} +#endif + +static char ** +do_setup_env(struct ssh *ssh, Session *s, const char *shell) +{ + char buf[256]; + size_t n; + u_int i, envsize; + char *ocp, *cp, *value, **env, *laddr; + struct passwd *pw = s->pw; +#if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN) + char *path = NULL; +#endif + + /* Initialize the environment. */ + envsize = 100; + env = 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 child's environment as they see fit + */ + ssh_gssapi_do_child(&env, &envsize); +#endif + + /* 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 */ + + if (!options.use_pam) { + 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")); + if (s->term) + child_set_env(&env, &envsize, "TERM", s->term); + if (s->display) + child_set_env(&env, &envsize, "DISPLAY", s->display); + + /* + * 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", + options.permit_user_env_allowlist); + } +#endif +#ifdef KRB5 + if (s->authctxt->krb5_ccname) + child_set_env(&env, &envsize, "KRB5CCNAME", + s->authctxt->krb5_ccname); +#endif + if (auth_sock_name != NULL) + child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, + auth_sock_name); + + + /* Set custom environment options from pubkey authentication. */ + if (options.permit_user_env) { + for (n = 0 ; n < auth_opts->nenv; n++) { + ocp = xstrdup(auth_opts->env[n]); + cp = strchr(ocp, '='); + if (cp != NULL) { + *cp = '\0'; + /* Apply PermitUserEnvironment allowlist */ + if (options.permit_user_env_allowlist == NULL || + match_pattern_list(ocp, + options.permit_user_env_allowlist, 0) == 1) + child_set_env(&env, &envsize, + ocp, cp + 1); + } + free(ocp); + } + } + + /* read $HOME/.ssh/environment. */ + if (options.permit_user_env) { + snprintf(buf, sizeof buf, "%.200s/%s/environment", + pw->pw_dir, _PATH_SSH_USER_DIR); + read_environment_file(&env, &envsize, buf, + options.permit_user_env_allowlist); + } + +#ifdef USE_PAM + /* + * Pull in any environment variables that may have + * been set by PAM. + */ + if (options.use_pam) { + char **p; + + /* + * Don't allow PAM-internal env vars to leak + * back into the session environment. + */ +#define PAM_ENV_DENYLIST "SSH_AUTH_INFO*,SSH_CONNECTION*" + p = fetch_pam_child_environment(); + copy_environment_denylist(p, &env, &envsize, + PAM_ENV_DENYLIST); + free_pam_environment(p); + + p = fetch_pam_environment(); + copy_environment_denylist(p, &env, &envsize, + PAM_ENV_DENYLIST); + free_pam_environment(p); + } +#endif /* USE_PAM */ + + /* Environment specified by admin */ + for (i = 0; i < options.num_setenv; i++) { + cp = xstrdup(options.setenv[i]); + if ((value = strchr(cp, '=')) == NULL) { + /* shouldn't happen; vars are checked in servconf.c */ + fatal("Invalid config SetEnv: %s", options.setenv[i]); + } + *value++ = '\0'; + child_set_env(&env, &envsize, cp, value); + free(cp); + } + + /* SSH_CLIENT deprecated */ + snprintf(buf, sizeof buf, "%.50s %d %d", + ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), + ssh_local_port(ssh)); + child_set_env(&env, &envsize, "SSH_CLIENT", buf); + + laddr = get_local_ipaddr(ssh_packet_get_connection_in(ssh)); + snprintf(buf, sizeof buf, "%.50s %d %.50s %d", + ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), + laddr, ssh_local_port(ssh)); + free(laddr); + child_set_env(&env, &envsize, "SSH_CONNECTION", buf); + + if (tun_fwd_ifnames != NULL) + child_set_env(&env, &envsize, "SSH_TUNNEL", tun_fwd_ifnames); + if (auth_info_file != NULL) + child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file); + if (s->ttyfd != -1) + child_set_env(&env, &envsize, "SSH_TTY", s->tty); + if (original_command) + child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", + original_command); + + 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(struct ssh *ssh, Session *s, const char *shell) +{ + FILE *f = NULL; + char *cmd = NULL, *user_rc = NULL; + int do_xauth; + struct stat st; + + do_xauth = + s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; + xasprintf(&user_rc, "%s/%s", s->pw->pw_dir, _PATH_SSH_USER_RC); + + /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ + if (!s->is_subsystem && options.adm_forced_command == NULL && + auth_opts->permit_user_rc && options.permit_user_rc && + stat(user_rc, &st) >= 0) { + if (xasprintf(&cmd, "%s -c '%s %s'", shell, _PATH_BSHELL, + user_rc) == -1) + fatal_f("xasprintf: %s", strerror(errno)); + 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", + 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); + } + if (xasprintf(&cmd, "%s -q -", options.xauth_location) == -1) + fatal_f("xasprintf: %s", strerror(errno)); + 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); + } + } + free(cmd); + free(user_rc); +} + +static void +do_nologin(struct passwd *pw) +{ + FILE *f = NULL; + char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; + struct stat sb; + +#ifdef HAVE_LOGIN_CAP + if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) + return; + nl = login_getcapstr(lc, "nologin", def_nl, def_nl); +#else + if (pw->pw_uid == 0) + return; + nl = def_nl; +#endif + if (stat(nl, &sb) == -1) + return; + + /* /etc/nologin exists. Print its contents if we can and exit. */ + logit("User %.100s not allowed because %s exists", pw->pw_name, nl); + if ((f = fopen(nl, "r")) != NULL) { + while (fgets(buf, sizeof(buf), f)) + fputs(buf, stderr); + fclose(f); + } + exit(254); +} + +/* + * Chroot into a directory after checking it for safety: all path components + * must be root-owned directories with strict permissions. + */ +static void +safely_chroot(const char *path, uid_t uid) +{ + const char *cp; + char component[PATH_MAX]; + struct stat st; + + if (!path_absolute(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_f("checking '%s'", component); + + if (stat(component, &st) != 0) + fatal_f("stat(\"%s\"): %s", + 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_f("chdir(/) after chroot: %s", strerror(errno)); + verbose("Changed root directory to \"%s\"", path); +} + +/* Set login name, uid, gid, and groups. */ +void +do_setusercontext(struct passwd *pw) +{ + char uidstr[32], *chroot_path, *tmp; + + platform_setusercontext(pw); + + if (platform_privileged_uidswap()) { +#ifdef HAVE_LOGIN_CAP + if (setusercontext(lc, pw, pw->pw_uid, + (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { + perror("unable to set user context"); + exit(1); + } +#else + 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(); +#endif + + platform_setusercontext_post_groups(pw); + + if (!in_chroot && options.chroot_directory != NULL && + strcasecmp(options.chroot_directory, "none") != 0) { + tmp = tilde_expand_filename(options.chroot_directory, + pw->pw_uid); + snprintf(uidstr, sizeof(uidstr), "%llu", + (unsigned long long)pw->pw_uid); + chroot_path = percent_expand(tmp, "h", pw->pw_dir, + "u", pw->pw_name, "U", uidstr, (char *)NULL); + safely_chroot(chroot_path, pw->pw_uid); + free(tmp); + free(chroot_path); + /* Make sure we don't attempt to chroot again */ + free(options.chroot_directory); + options.chroot_directory = NULL; + in_chroot = 1; + } + +#ifdef HAVE_LOGIN_CAP + if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { + perror("unable to set user context (setuser)"); + exit(1); + } + /* + * FreeBSD's setusercontext() will not apply the user's + * own umask setting unless running with the user's UID. + */ + (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK); +#else +# ifdef USE_LIBIAF + /* + * In a chroot environment, the set_id() will always fail; + * typically because of the lack of necessary authentication + * services and runtime such as ./usr/lib/libiaf.so, + * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the + * internal sftp chroot case. We'll lose auditing and ACLs but + * permanently_set_uid will take care of the rest. + */ + if (!in_chroot && set_id(pw->pw_name) != 0) + fatal("set_id(%s) Failed", pw->pw_name); +# endif /* USE_LIBIAF */ + /* Permanently switch to the desired uid. */ + permanently_set_uid(pw); +#endif + } else if (options.chroot_directory != NULL && + strcasecmp(options.chroot_directory, "none") != 0) { + fatal("server lacks privileges to chroot to ChrootDirectory"); + } + + if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) + fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); +} + +static void +do_pwchange(Session *s) +{ + fflush(NULL); + fprintf(stderr, "WARNING: Your password has expired.\n"); + if (s->ttyfd != -1) { + fprintf(stderr, + "You must change your password now and login again!\n"); +#ifdef WITH_SELINUX + setexeccon(NULL); +#endif +#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 +child_close_fds(struct ssh *ssh) +{ + extern int auth_sock; + + if (auth_sock != -1) { + close(auth_sock); + auth_sock = -1; + } + + if (ssh_packet_get_connection_in(ssh) == + ssh_packet_get_connection_out(ssh)) + close(ssh_packet_get_connection_in(ssh)); + else { + close(ssh_packet_get_connection_in(ssh)); + close(ssh_packet_get_connection_out(ssh)); + } + /* + * Close all descriptors related to channels. They will still remain + * open in the parent. + */ + /* XXX better use close-on-exec? -markus */ + channel_close_all(ssh); + + /* + * Close any extra file descriptors. Note that there may still be + * descriptors left by system functions. They will be closed later. + */ + endpwent(); + + /* Stop directing logs to a high-numbered fd before we close it */ + log_redirect_stderr_to(NULL); + + /* + * 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. + */ + closefrom(STDERR_FILENO + 1); +} + +/* + * 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(struct ssh *ssh, Session *s, const char *command) +{ + extern char **environ; + char **env, *argv[ARGV_MAX], remote_id[512]; + const char *shell, *shell0; + struct passwd *pw = s->pw; + int r = 0; + + sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); + + /* remove hostkey from the child's memory */ + destroy_sensitive_data(); + ssh_packet_clear_keys(ssh); + + /* Force a password change */ + if (s->authctxt->force_pwchange) { + do_setusercontext(pw); + child_close_fds(ssh); + do_pwchange(s); + exit(1); + } + + /* + * Login(1) does this as well, and it needs uid 0 for the "-h" + * switch, so we let login(1) to this for us. + */ +#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 && !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(ssh, s, shell); + +#ifdef HAVE_LOGIN_CAP + shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); +#endif + + /* + * 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 + * ssh_remote_ipaddr there. + */ + child_close_fds(ssh); + + /* + * 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) == -1) { + /* Suppress missing homedir warning for chroot case */ +#ifdef HAVE_LOGIN_CAP + r = login_getcapbool(lc, "requirehome", 0); +#endif + if (r || !in_chroot) { + fprintf(stderr, "Could not chdir to home " + "directory %s: %s\n", pw->pw_dir, + strerror(errno)); + } + if (r) + exit(1); + } + + closefrom(STDERR_FILENO + 1); + + do_rc_files(ssh, s, shell); + + /* restore SIGPIPE for child */ + ssh_signal(SIGPIPE, SIG_DFL); + + if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { + error("Connection from %s: refusing non-sftp session", + remote_id); + printf("This service allows sftp connections only.\n"); + fflush(NULL); + exit(1); + } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { + extern int optind, optreset; + int i; + char *p, *args; + + setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); + args = xstrdup(command ? command : "sftp-server"); + for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) + if (i < ARGV_MAX - 1) + argv[i++] = p; + argv[i] = NULL; + optind = optreset = 1; + __progname = argv[0]; +#ifdef WITH_SELINUX + ssh_selinux_change_context("sftpd_t"); +#endif + exit(sftp_server_main(i, argv, s->pw)); + } + + fflush(NULL); + + /* 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); +} + +void +session_unused(int id) +{ + debug3_f("session id %d unused", id); + if (id >= options.max_sessions || + id >= sessions_nalloc) { + fatal_f("insane session id %d (max %d nalloc %d)", + id, options.max_sessions, sessions_nalloc); + } + memset(&sessions[id], 0, 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) +{ + Session *s, *tmp; + + if (sessions_first_unused == -1) { + if (sessions_nalloc >= options.max_sessions) + return NULL; + debug2_f("allocate (allocated %d max %d)", + sessions_nalloc, options.max_sessions); + tmp = xrecallocarray(sessions, sessions_nalloc, + sessions_nalloc + 1, sizeof(*sessions)); + if (tmp == NULL) { + error_f("cannot allocate %d sessions", + sessions_nalloc + 1); + return NULL; + } + sessions = tmp; + session_unused(sessions_nalloc++); + } + + if (sessions_first_unused >= sessions_nalloc || + sessions_first_unused < 0) { + fatal_f("insane first_unused %d max %d nalloc %d", + sessions_first_unused, options.max_sessions, + sessions_nalloc); + } + + s = &sessions[sessions_first_unused]; + if (s->used) + fatal_f("session %d already used", 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 < sessions_nalloc; i++) { + Session *s = &sessions[i]; + + debug("dump: used %d next_unused %d session %d " + "channel %d pid %ld", + s->used, + s->next_unused, + s->self, + 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 < 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); + 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 < sessions_nalloc; 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 < 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 < sessions_nalloc; 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(struct ssh *ssh, Session *s) +{ + int r; + + if ((r = sshpkt_get_u32(ssh, &s->col)) != 0 || + (r = sshpkt_get_u32(ssh, &s->row)) != 0 || + (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || + (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); + return 1; +} + +static int +session_pty_req(struct ssh *ssh, Session *s) +{ + int r; + + if (!auth_opts->permit_pty_flag || !options.permit_tty) { + debug("Allocating a pty not permitted for this connection."); + return 0; + } + if (s->ttyfd != -1) { + ssh_packet_disconnect(ssh, "Protocol error: you already have a pty."); + return 0; + } + + if ((r = sshpkt_get_cstring(ssh, &s->term, NULL)) != 0 || + (r = sshpkt_get_u32(ssh, &s->col)) != 0 || + (r = sshpkt_get_u32(ssh, &s->row)) != 0 || + (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || + (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + if (strcmp(s->term, "") == 0) { + free(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)))) { + free(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); + + ssh_tty_parse_modes(ssh, s->ttyfd); + + if ((r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + 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); + + session_proctitle(s); + return 1; +} + +static int +session_subsystem_req(struct ssh *ssh, Session *s) +{ + struct stat st; + int r, success = 0; + char *prog, *cmd, *type; + u_int i; + + if ((r = sshpkt_get_cstring(ssh, &s->subsys, NULL)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + debug2("subsystem request for %.100s by user %s", s->subsys, + s->pw->pw_name); + + for (i = 0; i < options.num_subsystems; i++) { + if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { + prog = options.subsystem_command[i]; + cmd = options.subsystem_args[i]; + if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { + s->is_subsystem = SUBSYSTEM_INT_SFTP; + debug("subsystem: %s", prog); + } else { + if (stat(prog, &st) == -1) + debug("subsystem: cannot stat %s: %s", + prog, strerror(errno)); + s->is_subsystem = SUBSYSTEM_EXT; + debug("subsystem: exec() %s", cmd); + } + xasprintf(&type, "session:subsystem:%s", + options.subsystem_name[i]); + channel_set_xtype(ssh, s->chanid, type); + free(type); + success = do_exec(ssh, s, cmd) == 0; + break; + } + } + + if (!success) + logit("subsystem request for %.100s by user %s failed, " + "subsystem not found", s->subsys, s->pw->pw_name); + + return success; +} + +static int +session_x11_req(struct ssh *ssh, Session *s) +{ + int r, success; + u_char single_connection = 0; + + if (s->auth_proto != NULL || s->auth_data != NULL) { + error("session_x11_req: session %d: " + "x11 forwarding already active", s->self); + return 0; + } + if ((r = sshpkt_get_u8(ssh, &single_connection)) != 0 || + (r = sshpkt_get_cstring(ssh, &s->auth_proto, NULL)) != 0 || + (r = sshpkt_get_cstring(ssh, &s->auth_data, NULL)) != 0 || + (r = sshpkt_get_u32(ssh, &s->screen)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + s->single_connection = single_connection; + + if (xauth_valid_string(s->auth_proto) && + xauth_valid_string(s->auth_data)) + success = session_setup_x11fwd(ssh, s); + else { + success = 0; + error("Invalid X11 forwarding data"); + } + if (!success) { + free(s->auth_proto); + free(s->auth_data); + s->auth_proto = NULL; + s->auth_data = NULL; + } + return success; +} + +static int +session_shell_req(struct ssh *ssh, Session *s) +{ + int r; + + if ((r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + channel_set_xtype(ssh, s->chanid, "session:shell"); + + return do_exec(ssh, s, NULL) == 0; +} + +static int +session_exec_req(struct ssh *ssh, Session *s) +{ + u_int success; + int r; + char *command = NULL; + + if ((r = sshpkt_get_cstring(ssh, &command, NULL)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + channel_set_xtype(ssh, s->chanid, "session:command"); + + success = do_exec(ssh, s, command) == 0; + free(command); + return success; +} + +static int +session_break_req(struct ssh *ssh, Session *s) +{ + int r; + + if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* ignore */ + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) == -1) + return 0; + return 1; +} + +static int +session_env_req(struct ssh *ssh, Session *s) +{ + char *name, *val; + u_int i; + int r; + + if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || + (r = sshpkt_get_cstring(ssh, &val, NULL)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + + /* 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 = xrecallocarray(s->env, s->num_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: + free(name); + free(val); + return (0); +} + +/* + * Conversion of signals from ssh channel request names. + * Subset of signals from RFC 4254 section 6.10C, with SIGINFO as + * local extension. + */ +static int +name2sig(char *name) +{ +#define SSH_SIG(x) if (strcmp(name, #x) == 0) return SIG ## x + SSH_SIG(HUP); + SSH_SIG(INT); + SSH_SIG(KILL); + SSH_SIG(QUIT); + SSH_SIG(TERM); + SSH_SIG(USR1); + SSH_SIG(USR2); +#undef SSH_SIG +#ifdef SIGINFO + if (strcmp(name, "INFO@openssh.com") == 0) + return SIGINFO; +#endif + return -1; +} + +static int +session_signal_req(struct ssh *ssh, Session *s) +{ + char *signame = NULL; + int r, sig, success = 0; + + if ((r = sshpkt_get_cstring(ssh, &signame, NULL)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) { + error_fr(r, "parse"); + goto out; + } + if ((sig = name2sig(signame)) == -1) { + error_f("unsupported signal \"%s\"", signame); + goto out; + } + if (s->pid <= 0) { + error_f("no pid for session %d", s->self); + goto out; + } + if (s->forced || s->is_subsystem) { + error_f("refusing to send signal %s to %s session", + signame, s->forced ? "forced-command" : "subsystem"); + goto out; + } + if (!use_privsep || mm_is_monitor()) { + error_f("session signalling requires privilege separation"); + goto out; + } + + debug_f("signal %s, killpg(%ld, %d)", signame, (long)s->pid, sig); + temporarily_use_uid(s->pw); + r = killpg(s->pid, sig); + restore_uid(); + if (r != 0) { + error_f("killpg(%ld, %d): %s", (long)s->pid, + sig, strerror(errno)); + goto out; + } + + /* success */ + success = 1; + out: + free(signame); + return success; +} + +static int +session_auth_agent_req(struct ssh *ssh, Session *s) +{ + static int called = 0; + int r; + + if ((r = sshpkt_get_end(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: parse packet", __func__); + if (!auth_opts->permit_agent_forwarding_flag || + !options.allow_agent_forwarding) { + debug_f("agent forwarding disabled"); + return 0; + } + if (called) { + return 0; + } else { + called = 1; + return auth_input_request_forwarding(ssh, s->pw); + } +} + +int +session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype) +{ + int success = 0; + Session *s; + + if ((s = session_by_channel(c->self)) == NULL) { + logit_f("no session %d req %.100s", c->self, rtype); + return 0; + } + debug_f("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(ssh, s); + } else if (strcmp(rtype, "exec") == 0) { + success = session_exec_req(ssh, s); + } else if (strcmp(rtype, "pty-req") == 0) { + success = session_pty_req(ssh, s); + } else if (strcmp(rtype, "x11-req") == 0) { + success = session_x11_req(ssh, s); + } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { + success = session_auth_agent_req(ssh, s); + } else if (strcmp(rtype, "subsystem") == 0) { + success = session_subsystem_req(ssh, s); + } else if (strcmp(rtype, "env") == 0) { + success = session_env_req(ssh, s); + } + } + if (strcmp(rtype, "window-change") == 0) { + success = session_window_change_req(ssh, s); + } else if (strcmp(rtype, "break") == 0) { + success = session_break_req(ssh, s); + } else if (strcmp(rtype, "signal") == 0) { + success = session_signal_req(ssh, s); + } + + return success; +} + +void +session_set_fds(struct ssh *ssh, Session *s, + int fdin, int fdout, int fderr, int ignore_fderr, int is_tty) +{ + /* + * 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(ssh, s->chanid, + fdout, fdin, fderr, + ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, + 1, is_tty, 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_f("no session"); + return; + } + if (s->ttyfd == -1) + return; + + debug_f("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 (s->ptymaster != -1 && close(s->ptymaster) == -1) + 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(struct ssh *ssh, int id) +{ + Channel *c; + + if ((c = channel_by_id(ssh, id)) == NULL) { + debug_f("x11 channel %d missing", id); + } else { + /* Detach X11 listener */ + debug_f("detach x11 channel %d", id); + channel_cancel_cleanup(ssh, id); + if (c->ostate != CHAN_OUTPUT_CLOSED) + chan_mark_dead(ssh, c); + } +} + +static void +session_close_single_x11(struct ssh *ssh, int id, int force, void *arg) +{ + Session *s; + u_int i; + + debug3_f("channel %d", id); + channel_cancel_cleanup(ssh, id); + if ((s = session_by_x11_channel(id)) == NULL) + fatal_f("no x11 channel %d", id); + for (i = 0; s->x11_chanids[i] != -1; i++) { + debug_f("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(ssh, s->x11_chanids[i]); + } + free(s->x11_chanids); + s->x11_chanids = NULL; + free(s->display); + s->display = NULL; + free(s->auth_proto); + s->auth_proto = NULL; + free(s->auth_data); + s->auth_data = NULL; + free(s->auth_display); + s->auth_display = NULL; +} + +static void +session_exit_message(struct ssh *ssh, Session *s, int status) +{ + Channel *c; + int r; + char *note = NULL; + + if ((c = channel_lookup(ssh, s->chanid)) == NULL) + fatal_f("session %d: no channel %d", s->self, s->chanid); + + if (WIFEXITED(status)) { + channel_request_start(ssh, s->chanid, "exit-status", 0); + if ((r = sshpkt_put_u32(ssh, WEXITSTATUS(status))) != 0 || + (r = sshpkt_send(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: exit reply", __func__); + xasprintf(¬e, "exit %d", WEXITSTATUS(status)); + } else if (WIFSIGNALED(status)) { + channel_request_start(ssh, s->chanid, "exit-signal", 0); +#ifndef WCOREDUMP +# define WCOREDUMP(x) (0) +#endif + if ((r = sshpkt_put_cstring(ssh, sig2name(WTERMSIG(status)))) != 0 || + (r = sshpkt_put_u8(ssh, WCOREDUMP(status)? 1 : 0)) != 0 || + (r = sshpkt_put_cstring(ssh, "")) != 0 || + (r = sshpkt_put_cstring(ssh, "")) != 0 || + (r = sshpkt_send(ssh)) != 0) + sshpkt_fatal(ssh, r, "%s: exit reply", __func__); + xasprintf(¬e, "signal %d%s", WTERMSIG(status), + WCOREDUMP(status) ? " core dumped" : ""); + } else { + /* Some weird exit cause. Just exit. */ + ssh_packet_disconnect(ssh, "wait returned status %04x.", + status); + } + + debug_f("session %d channel %d pid %ld %s", s->self, s->chanid, + (long)s->pid, note == NULL ? "UNKNOWN" : note); + free(note); + + /* disconnect channel */ + debug_f("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 child sessions close their fds. + */ + channel_register_cleanup(ssh, 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(ssh, c); +} + +void +session_close(struct ssh *ssh, Session *s) +{ + u_int i; + + verbose("Close session: user %s from %.200s port %d id %d", + s->pw->pw_name, + ssh_remote_ipaddr(ssh), + ssh_remote_port(ssh), + s->self); + + if (s->ttyfd != -1) + session_pty_cleanup(s); + free(s->term); + free(s->display); + free(s->x11_chanids); + free(s->auth_display); + free(s->auth_data); + free(s->auth_proto); + free(s->subsys); + if (s->env != NULL) { + for (i = 0; i < s->num_env; i++) { + free(s->env[i].name); + free(s->env[i].val); + } + free(s->env); + } + session_proctitle(s); + session_unused(s->self); +} + +void +session_close_by_pid(struct ssh *ssh, pid_t pid, int status) +{ + Session *s = session_by_pid(pid); + if (s == NULL) { + debug_f("no session for pid %ld", (long)pid); + return; + } + if (s->chanid != -1) + session_exit_message(ssh, 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(struct ssh *ssh, int id, int force, void *arg) +{ + Session *s = session_by_channel(id); + u_int i; + + if (s == NULL) { + debug_f("no session for id %d", id); + return; + } + debug_f("channel %d child %ld", id, (long)s->pid); + if (s->pid != 0) { + debug_f("channel %d: has child, ttyfd %d", id, s->ttyfd); + /* + * delay detach of session (unless this is a forced close), + * but release pty, since the fd's to the child are already + * closed + */ + if (s->ttyfd != -1) + session_pty_cleanup(s); + if (!force) + return; + } + /* detach by removing callback */ + channel_cancel_cleanup(ssh, 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(ssh, s->x11_chanids[i]); + s->x11_chanids[i] = -1; + } + } + + s->chanid = -1; + session_close(ssh, s); +} + +void +session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *)) +{ + int i; + for (i = 0; i < sessions_nalloc; i++) { + Session *s = &sessions[i]; + if (s->used) { + if (closefunc != NULL) + closefunc(s); + else + session_close(ssh, s); + } + } +} + +static char * +session_tty_list(void) +{ + static char buf[1024]; + int i; + char *cp; + + buf[0] = '\0'; + 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); + } + } + 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(struct ssh *ssh, Session *s) +{ + struct stat st; + char display[512], auth_display[512]; + char hostname[NI_MAXHOST]; + u_int i; + + if (!auth_opts->permit_x11_forwarding_flag) { + ssh_packet_send_debug(ssh, "X11 forwarding disabled by key options."); + return 0; + } + if (!options.x11_forwarding) { + debug("X11 forwarding disabled in server configuration file."); + return 0; + } + if (options.xauth_location == NULL || + (stat(options.xauth_location, &st) == -1)) { + ssh_packet_send_debug(ssh, "No xauth program; cannot forward X11."); + return 0; + } + if (s->display != NULL) { + debug("X11 display already set."); + return 0; + } + if (x11_create_display_inet(ssh, 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(ssh, s->x11_chanids[i], + session_close_single_x11, 0); + } + + /* Set up a suitable value for the DISPLAY variable. */ + if (gethostname(hostname, sizeof(hostname)) == -1) + 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."); + ssh_packet_send_debug(ssh, "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(struct ssh *ssh, Authctxt *authctxt) +{ + server_loop2(ssh, authctxt); +} + +void +do_cleanup(struct ssh *ssh, 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 (options.gss_cleanup_creds) + ssh_gssapi_cleanup_creds(); +#endif + + /* remove agent socket */ + auth_sock_cleanup_proc(authctxt->pw); + + /* remove userauth info */ + if (auth_info_file != NULL) { + temporarily_use_uid(authctxt->pw); + unlink(auth_info_file); + restore_uid(); + free(auth_info_file); + auth_info_file = NULL; + } + + /* + * Cleanup ptys/utmp only if privsep is disabled, + * or if running in monitor. + */ + if (!use_privsep || mm_is_monitor()) + session_destroy_all(ssh, session_pty_cleanup2); +} + +/* Return a name for the remote host that fits inside utmp_size */ + +const char * +session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns) +{ + const char *remote = ""; + + if (utmp_size > 0) + remote = auth_get_canonical_hostname(ssh, use_dns); + if (utmp_size == 0 || strlen(remote) > utmp_size) + remote = ssh_remote_ipaddr(ssh); + return remote; +} + |