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/* $OpenBSD: session.c,v 1.327 2020/12/14 03:13:12 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> | |
#include <sys/param.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 "compat.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 socket", | |
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 = hpdelim(&cp)) == 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); | |
} | |
/* 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 %p " | |
"channel %d pid %ld", | |
s->used, | |
s->next_unused, | |
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 < 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; | |
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); | |
} | |
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__); | |
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__); | |
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, 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; | |
if ((c = channel_lookup(ssh, s->chanid)) == NULL) | |
fatal_f("session %d: no channel %d", s->self, s->chanid); | |
debug_f("session %d channel %d pid %ld", | |
s->self, s->chanid, (long)s->pid); | |
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__); | |
} 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__); | |
} else { | |
/* Some weird exit cause. Just exit. */ | |
ssh_packet_disconnect(ssh, "wait returned status %04x.", status); | |
} | |
/* 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, 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, 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(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; | |
} | |