openssh-portable/auth.c

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/* $OpenBSD: auth.c,v 1.137 2019/01/19 21:37:48 djm Exp $ */
2002-05-22 07:06:28 +02:00
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
- (djm) Merge OpenBSD changes: - markus@cvs.openbsd.org 2000/09/05 02:59:57 [session.c] print hostname (not hushlogin) - markus@cvs.openbsd.org 2000/09/05 13:18:48 [authfile.c ssh-add.c] enable ssh-add -d for DSA keys - markus@cvs.openbsd.org 2000/09/05 13:20:49 [sftp-server.c] cleanup - markus@cvs.openbsd.org 2000/09/06 03:46:41 [authfile.h] prototype - deraadt@cvs.openbsd.org 2000/09/07 14:27:56 [ALL] cleanup copyright notices on all files. I have attempted to be accurate with the details. everything is now under Tatu's licence (which I copied from his readme), and/or the core-sdi bsd-ish thing for deattack, or various openbsd developers under a 2-term bsd licence. We're not changing any rules, just being accurate. - markus@cvs.openbsd.org 2000/09/07 14:40:30 [channels.c channels.h clientloop.c serverloop.c ssh.c] cleanup window and packet sizes for ssh2 flow control; ok niels - markus@cvs.openbsd.org 2000/09/07 14:53:00 [scp.c] typo - markus@cvs.openbsd.org 2000/09/07 15:13:37 [auth-options.c auth-options.h auth-rh-rsa.c auth-rsa.c auth.c] [authfile.h canohost.c channels.h compat.c hostfile.h log.c match.h] [pty.c readconf.c] some more Copyright fixes - markus@cvs.openbsd.org 2000/09/08 03:02:51 [README.openssh2] bye bye - deraadt@cvs.openbsd.org 2000/09/11 18:38:33 [LICENCE cipher.c] a few more comments about it being ARC4 not RC4 - markus@cvs.openbsd.org 2000/09/12 14:53:11 [log-client.c log-server.c log.c ssh.1 ssh.c ssh.h sshd.8 sshd.c] multiple debug levels - markus@cvs.openbsd.org 2000/09/14 14:25:15 [clientloop.c] typo - deraadt@cvs.openbsd.org 2000/09/15 01:13:51 [ssh-agent.c] check return value for setenv(3) for failure, and deal appropriately
2000-09-16 04:29:08 +02:00
*
* 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/stat.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_PATHS_H
2006-03-15 01:18:26 +01:00
# include <paths.h>
#endif
#include <pwd.h>
#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#ifdef USE_SHADOW
#include <shadow.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <netdb.h>
#include <time.h>
Hopefully things did not get mixed around too much. It compiles under Linux and works. So that is at least a good sign. =) 20010122 - (bal) OpenBSD Resync - markus@cvs.openbsd.org 2001/01/19 12:45:26 GMT 2001 by markus [servconf.c ssh.h sshd.c] only auth-chall.c needs #ifdef SKEY - markus@cvs.openbsd.org 2001/01/19 15:55:10 GMT 2001 by markus [auth-krb4.c auth-options.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth1.c auth2.c channels.c clientloop.c dh.c dispatch.c nchan.c packet.c pathname.h readconf.c scp.c servconf.c serverloop.c session.c ssh-add.c ssh-keygen.c ssh-keyscan.c ssh.c ssh.h ssh1.h sshconnect1.c sshd.c ttymodes.c] move ssh1 definitions to ssh1.h, pathnames to pathnames.h - markus@cvs.openbsd.org 2001/01/19 16:48:14 [sshd.8] fix typo; from stevesk@ - markus@cvs.openbsd.org 2001/01/19 16:50:58 [ssh-dss.c] clear and free digest, make consistent with other code (use dlen); from stevesk@ - markus@cvs.openbsd.org 2001/01/20 15:55:20 GMT 2001 by markus [auth-options.c auth-options.h auth-rsa.c auth2.c] pass the filename to auth_parse_options() - markus@cvs.openbsd.org 2001/01/20 17:59:40 GMT 2001 [readconf.c] fix SIGSEGV from -o ""; problem noted by jehsom@togetherweb.com - stevesk@cvs.openbsd.org 2001/01/20 18:20:29 [sshconnect2.c] dh_new_group() does not return NULL. ok markus@ - markus@cvs.openbsd.org 2001/01/20 21:33:42 [ssh-add.c] do not loop forever if askpass does not exist; from andrew@pimlott.ne.mediaone.net - djm@cvs.openbsd.org 2001/01/20 23:00:56 [servconf.c] Check for NULL return from strdelim; ok markus - djm@cvs.openbsd.org 2001/01/20 23:02:07 [readconf.c] KNF; ok markus - jakob@cvs.openbsd.org 2001/01/21 9:00:33 [ssh-keygen.1] remove -R flag; ok markus@ - markus@cvs.openbsd.org 2001/01/21 19:05:40 [atomicio.c automicio.h auth-chall.c auth-krb4.c auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth.c auth.h auth1.c auth2-chall.c auth2.c authfd.c authfile.c bufaux.c bufaux.h buffer.c canahost.c canahost.h channels.c cipher.c cli.c clientloop.c clientloop.h compat.c compress.c deattack.c dh.c dispatch.c groupaccess.c hmac.c hostfile.c kex.c key.c key.h log-client.c log-server.c log.c log.h login.c login.h match.c misc.c misc.h nchan.c packet.c pty.c radix.h readconf.c readpass.c readpass.h rsa.c scp.c servconf.c serverloop.c serverloop.h session.c sftp-server.c ssh-add.c ssh-agent.c ssh-dss.c ssh-keygen.c ssh-keyscan.c ssh-rsa.c ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c sshd.c tildexpand.c tildexpand.h ttysmodes.c uidswap.c xmalloc.c] split ssh.h and try to cleanup the #include mess. remove unnecessary #includes. rename util.[ch] -> misc.[ch] - (bal) renamed 'PIDDIR' to '_PATH_SSH_PIDDIR' to match OpenBSD tree - (bal) Moved #ifdef KRB4 in auth-krb4.c above the #include to resolve conflict when compiling for non-kerb install - (bal) removed the #ifdef SKEY in auth1.c to match Markus' changes on 1/19.
2001-01-22 06:34:40 +01:00
#include "xmalloc.h"
#include "match.h"
#include "groupaccess.h"
#include "log.h"
#include "sshbuf.h"
#include "misc.h"
Hopefully things did not get mixed around too much. It compiles under Linux and works. So that is at least a good sign. =) 20010122 - (bal) OpenBSD Resync - markus@cvs.openbsd.org 2001/01/19 12:45:26 GMT 2001 by markus [servconf.c ssh.h sshd.c] only auth-chall.c needs #ifdef SKEY - markus@cvs.openbsd.org 2001/01/19 15:55:10 GMT 2001 by markus [auth-krb4.c auth-options.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth1.c auth2.c channels.c clientloop.c dh.c dispatch.c nchan.c packet.c pathname.h readconf.c scp.c servconf.c serverloop.c session.c ssh-add.c ssh-keygen.c ssh-keyscan.c ssh.c ssh.h ssh1.h sshconnect1.c sshd.c ttymodes.c] move ssh1 definitions to ssh1.h, pathnames to pathnames.h - markus@cvs.openbsd.org 2001/01/19 16:48:14 [sshd.8] fix typo; from stevesk@ - markus@cvs.openbsd.org 2001/01/19 16:50:58 [ssh-dss.c] clear and free digest, make consistent with other code (use dlen); from stevesk@ - markus@cvs.openbsd.org 2001/01/20 15:55:20 GMT 2001 by markus [auth-options.c auth-options.h auth-rsa.c auth2.c] pass the filename to auth_parse_options() - markus@cvs.openbsd.org 2001/01/20 17:59:40 GMT 2001 [readconf.c] fix SIGSEGV from -o ""; problem noted by jehsom@togetherweb.com - stevesk@cvs.openbsd.org 2001/01/20 18:20:29 [sshconnect2.c] dh_new_group() does not return NULL. ok markus@ - markus@cvs.openbsd.org 2001/01/20 21:33:42 [ssh-add.c] do not loop forever if askpass does not exist; from andrew@pimlott.ne.mediaone.net - djm@cvs.openbsd.org 2001/01/20 23:00:56 [servconf.c] Check for NULL return from strdelim; ok markus - djm@cvs.openbsd.org 2001/01/20 23:02:07 [readconf.c] KNF; ok markus - jakob@cvs.openbsd.org 2001/01/21 9:00:33 [ssh-keygen.1] remove -R flag; ok markus@ - markus@cvs.openbsd.org 2001/01/21 19:05:40 [atomicio.c automicio.h auth-chall.c auth-krb4.c auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth.c auth.h auth1.c auth2-chall.c auth2.c authfd.c authfile.c bufaux.c bufaux.h buffer.c canahost.c canahost.h channels.c cipher.c cli.c clientloop.c clientloop.h compat.c compress.c deattack.c dh.c dispatch.c groupaccess.c hmac.c hostfile.c kex.c key.c key.h log-client.c log-server.c log.c log.h login.c login.h match.c misc.c misc.h nchan.c packet.c pty.c radix.h readconf.c readpass.c readpass.h rsa.c scp.c servconf.c serverloop.c serverloop.h session.c sftp-server.c ssh-add.c ssh-agent.c ssh-dss.c ssh-keygen.c ssh-keyscan.c ssh-rsa.c ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c sshd.c tildexpand.c tildexpand.h ttysmodes.c uidswap.c xmalloc.c] split ssh.h and try to cleanup the #include mess. remove unnecessary #includes. rename util.[ch] -> misc.[ch] - (bal) renamed 'PIDDIR' to '_PATH_SSH_PIDDIR' to match OpenBSD tree - (bal) Moved #ifdef KRB4 in auth-krb4.c above the #include to resolve conflict when compiling for non-kerb install - (bal) removed the #ifdef SKEY in auth1.c to match Markus' changes on 1/19.
2001-01-22 06:34:40 +01:00
#include "servconf.h"
#include "sshkey.h"
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
2006-08-05 04:39:39 +02:00
#include "hostfile.h"
#include "auth.h"
#include "auth-options.h"
Hopefully things did not get mixed around too much. It compiles under Linux and works. So that is at least a good sign. =) 20010122 - (bal) OpenBSD Resync - markus@cvs.openbsd.org 2001/01/19 12:45:26 GMT 2001 by markus [servconf.c ssh.h sshd.c] only auth-chall.c needs #ifdef SKEY - markus@cvs.openbsd.org 2001/01/19 15:55:10 GMT 2001 by markus [auth-krb4.c auth-options.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth1.c auth2.c channels.c clientloop.c dh.c dispatch.c nchan.c packet.c pathname.h readconf.c scp.c servconf.c serverloop.c session.c ssh-add.c ssh-keygen.c ssh-keyscan.c ssh.c ssh.h ssh1.h sshconnect1.c sshd.c ttymodes.c] move ssh1 definitions to ssh1.h, pathnames to pathnames.h - markus@cvs.openbsd.org 2001/01/19 16:48:14 [sshd.8] fix typo; from stevesk@ - markus@cvs.openbsd.org 2001/01/19 16:50:58 [ssh-dss.c] clear and free digest, make consistent with other code (use dlen); from stevesk@ - markus@cvs.openbsd.org 2001/01/20 15:55:20 GMT 2001 by markus [auth-options.c auth-options.h auth-rsa.c auth2.c] pass the filename to auth_parse_options() - markus@cvs.openbsd.org 2001/01/20 17:59:40 GMT 2001 [readconf.c] fix SIGSEGV from -o ""; problem noted by jehsom@togetherweb.com - stevesk@cvs.openbsd.org 2001/01/20 18:20:29 [sshconnect2.c] dh_new_group() does not return NULL. ok markus@ - markus@cvs.openbsd.org 2001/01/20 21:33:42 [ssh-add.c] do not loop forever if askpass does not exist; from andrew@pimlott.ne.mediaone.net - djm@cvs.openbsd.org 2001/01/20 23:00:56 [servconf.c] Check for NULL return from strdelim; ok markus - djm@cvs.openbsd.org 2001/01/20 23:02:07 [readconf.c] KNF; ok markus - jakob@cvs.openbsd.org 2001/01/21 9:00:33 [ssh-keygen.1] remove -R flag; ok markus@ - markus@cvs.openbsd.org 2001/01/21 19:05:40 [atomicio.c automicio.h auth-chall.c auth-krb4.c auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth.c auth.h auth1.c auth2-chall.c auth2.c authfd.c authfile.c bufaux.c bufaux.h buffer.c canahost.c canahost.h channels.c cipher.c cli.c clientloop.c clientloop.h compat.c compress.c deattack.c dh.c dispatch.c groupaccess.c hmac.c hostfile.c kex.c key.c key.h log-client.c log-server.c log.c log.h login.c login.h match.c misc.c misc.h nchan.c packet.c pty.c radix.h readconf.c readpass.c readpass.h rsa.c scp.c servconf.c serverloop.c serverloop.h session.c sftp-server.c ssh-add.c ssh-agent.c ssh-dss.c ssh-keygen.c ssh-keyscan.c ssh-rsa.c ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c sshd.c tildexpand.c tildexpand.h ttysmodes.c uidswap.c xmalloc.c] split ssh.h and try to cleanup the #include mess. remove unnecessary #includes. rename util.[ch] -> misc.[ch] - (bal) renamed 'PIDDIR' to '_PATH_SSH_PIDDIR' to match OpenBSD tree - (bal) Moved #ifdef KRB4 in auth-krb4.c above the #include to resolve conflict when compiling for non-kerb install - (bal) removed the #ifdef SKEY in auth1.c to match Markus' changes on 1/19.
2001-01-22 06:34:40 +01:00
#include "canohost.h"
#include "uidswap.h"
#include "packet.h"
#include "loginrec.h"
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
2006-08-05 04:39:39 +02:00
#ifdef GSSAPI
#include "ssh-gss.h"
#endif
#include "authfile.h"
#include "monitor_wrap.h"
#include "authfile.h"
#include "ssherr.h"
#include "compat.h"
#include "channels.h"
#include "opacket.h" /* XXX */
extern struct ssh *active_state; /* XXX */
/* import */
extern ServerOptions options;
extern int use_privsep;
extern struct sshbuf *loginmsg;
extern struct passwd *privsep_pw;
extern struct sshauthopt *auth_opts;
/* Debugging messages */
static struct sshbuf *auth_debug;
/*
* Check if the user is allowed to log in via ssh. If user is listed
* in DenyUsers or one of user's groups is listed in DenyGroups, false
* will be returned. If AllowUsers isn't empty and user isn't listed
* there, or if AllowGroups isn't empty and one of user's groups isn't
* listed there, false will be returned.
* If the user's shell is not executable, false will be returned.
* Otherwise true is returned.
*/
int
allowed_user(struct passwd * pw)
{
struct ssh *ssh = active_state; /* XXX */
struct stat st;
const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
u_int i;
int r;
#ifdef USE_SHADOW
struct spwd *spw = NULL;
#endif
/* Shouldn't be called if pw is NULL, but better safe than sorry... */
if (!pw || !pw->pw_name)
return 0;
#ifdef USE_SHADOW
if (!options.use_pam)
spw = getspnam(pw->pw_name);
#ifdef HAS_SHADOW_EXPIRE
if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
return 0;
#endif /* HAS_SHADOW_EXPIRE */
#endif /* USE_SHADOW */
/* grab passwd field for locked account check */
passwd = pw->pw_passwd;
#ifdef USE_SHADOW
if (spw != NULL)
#ifdef USE_LIBIAF
passwd = get_iaf_password(pw);
#else
passwd = spw->sp_pwdp;
#endif /* USE_LIBIAF */
#endif
/* check for locked account */
if (!options.use_pam && passwd && *passwd) {
int locked = 0;
#ifdef LOCKED_PASSWD_STRING
if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
locked = 1;
#endif
#ifdef LOCKED_PASSWD_PREFIX
if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
strlen(LOCKED_PASSWD_PREFIX)) == 0)
locked = 1;
#endif
#ifdef LOCKED_PASSWD_SUBSTR
if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
locked = 1;
#endif
#ifdef USE_LIBIAF
free((void *) passwd);
#endif /* USE_LIBIAF */
if (locked) {
logit("User %.100s not allowed because account is locked",
pw->pw_name);
return 0;
}
}
/*
* Deny if shell does not exist or is not executable unless we
* are chrooting.
*/
if (options.chroot_directory == NULL ||
strcasecmp(options.chroot_directory, "none") == 0) {
char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
_PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
if (stat(shell, &st) != 0) {
logit("User %.100s not allowed because shell %.100s "
"does not exist", pw->pw_name, shell);
free(shell);
return 0;
}
if (S_ISREG(st.st_mode) == 0 ||
(st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
logit("User %.100s not allowed because shell %.100s "
"is not executable", pw->pw_name, shell);
free(shell);
return 0;
}
free(shell);
}
if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
options.num_deny_groups > 0 || options.num_allow_groups > 0) {
hostname = auth_get_canonical_hostname(ssh, options.use_dns);
ipaddr = ssh_remote_ipaddr(ssh);
}
/* Return false if user is listed in DenyUsers */
if (options.num_deny_users > 0) {
for (i = 0; i < options.num_deny_users; i++) {
r = match_user(pw->pw_name, hostname, ipaddr,
options.deny_users[i]);
if (r < 0) {
fatal("Invalid DenyUsers pattern \"%.100s\"",
options.deny_users[i]);
} else if (r != 0) {
logit("User %.100s from %.100s not allowed "
"because listed in DenyUsers",
pw->pw_name, hostname);
return 0;
}
}
}
/* Return false if AllowUsers isn't empty and user isn't listed there */
if (options.num_allow_users > 0) {
for (i = 0; i < options.num_allow_users; i++) {
r = match_user(pw->pw_name, hostname, ipaddr,
options.allow_users[i]);
if (r < 0) {
fatal("Invalid AllowUsers pattern \"%.100s\"",
options.allow_users[i]);
} else if (r == 1)
break;
}
/* i < options.num_allow_users iff we break for loop */
if (i >= options.num_allow_users) {
logit("User %.100s from %.100s not allowed because "
"not listed in AllowUsers", pw->pw_name, hostname);
return 0;
}
}
if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
/* Get the user's group access list (primary and supplementary) */
if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
logit("User %.100s from %.100s not allowed because "
"not in any group", pw->pw_name, hostname);
return 0;
}
/* Return false if one of user's groups is listed in DenyGroups */
if (options.num_deny_groups > 0)
if (ga_match(options.deny_groups,
options.num_deny_groups)) {
ga_free();
logit("User %.100s from %.100s not allowed "
"because a group is listed in DenyGroups",
pw->pw_name, hostname);
return 0;
}
/*
* Return false if AllowGroups isn't empty and one of user's groups
* isn't listed there
*/
if (options.num_allow_groups > 0)
if (!ga_match(options.allow_groups,
options.num_allow_groups)) {
ga_free();
logit("User %.100s from %.100s not allowed "
"because none of user's groups are listed "
"in AllowGroups", pw->pw_name, hostname);
return 0;
}
ga_free();
}
#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
if (!sys_auth_allowed_user(pw, loginmsg))
return 0;
#endif
/* We found no reason not to let this user try to log on... */
return 1;
}
/*
* Formats any key left in authctxt->auth_method_key for inclusion in
* auth_log()'s message. Also includes authxtct->auth_method_info if present.
*/
static char *
format_method_key(Authctxt *authctxt)
{
const struct sshkey *key = authctxt->auth_method_key;
const char *methinfo = authctxt->auth_method_info;
char *fp, *cafp, *ret = NULL;
if (key == NULL)
return NULL;
if (sshkey_is_cert(key)) {
fp = sshkey_fingerprint(key,
options.fingerprint_hash, SSH_FP_DEFAULT);
cafp = sshkey_fingerprint(key->cert->signature_key,
options.fingerprint_hash, SSH_FP_DEFAULT);
xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s",
sshkey_type(key), fp == NULL ? "(null)" : fp,
key->cert->key_id,
(unsigned long long)key->cert->serial,
sshkey_type(key->cert->signature_key),
cafp == NULL ? "(null)" : cafp,
methinfo == NULL ? "" : ", ",
methinfo == NULL ? "" : methinfo);
free(fp);
free(cafp);
} else {
fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT);
xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
fp == NULL ? "(null)" : fp,
methinfo == NULL ? "" : ", ",
methinfo == NULL ? "" : methinfo);
free(fp);
}
return ret;
}
void
auth_log(Authctxt *authctxt, int authenticated, int partial,
const char *method, const char *submethod)
{
struct ssh *ssh = active_state; /* XXX */
int level = SYSLOG_LEVEL_VERBOSE;
const char *authmsg;
char *extra = NULL;
if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
return;
/* Raise logging level */
if (authenticated == 1 ||
!authctxt->valid ||
authctxt->failures >= options.max_authtries / 2 ||
strcmp(method, "password") == 0)
level = SYSLOG_LEVEL_INFO;
if (authctxt->postponed)
authmsg = "Postponed";
else if (partial)
authmsg = "Partial";
else
authmsg = authenticated ? "Accepted" : "Failed";
if ((extra = format_method_key(authctxt)) == NULL) {
if (authctxt->auth_method_info != NULL)
extra = xstrdup(authctxt->auth_method_info);
}
do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
authmsg,
method,
submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
authctxt->valid ? "" : "invalid user ",
authctxt->user,
ssh_remote_ipaddr(ssh),
ssh_remote_port(ssh),
extra != NULL ? ": " : "",
extra != NULL ? extra : "");
free(extra);
#ifdef CUSTOM_FAILED_LOGIN
if (authenticated == 0 && !authctxt->postponed &&
(strcmp(method, "password") == 0 ||
strncmp(method, "keyboard-interactive", 20) == 0 ||
strcmp(method, "challenge-response") == 0))
record_failed_login(authctxt->user,
auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
# ifdef WITH_AIXAUTHENTICATE
if (authenticated)
sys_auth_record_login(authctxt->user,
auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
loginmsg);
# endif
#endif
#ifdef SSH_AUDIT_EVENTS
if (authenticated == 0 && !authctxt->postponed)
audit_event(audit_classify_auth(method));
#endif
}
void
auth_maxtries_exceeded(Authctxt *authctxt)
{
struct ssh *ssh = active_state; /* XXX */
error("maximum authentication attempts exceeded for "
"%s%.100s from %.200s port %d ssh2",
authctxt->valid ? "" : "invalid user ",
authctxt->user,
ssh_remote_ipaddr(ssh),
ssh_remote_port(ssh));
packet_disconnect("Too many authentication failures");
/* NOTREACHED */
}
/*
* Check whether root logins are disallowed.
*/
int
auth_root_allowed(struct ssh *ssh, const char *method)
{
switch (options.permit_root_login) {
case PERMIT_YES:
return 1;
case PERMIT_NO_PASSWD:
if (strcmp(method, "publickey") == 0 ||
strcmp(method, "hostbased") == 0 ||
strcmp(method, "gssapi-with-mic") == 0)
return 1;
break;
case PERMIT_FORCED_ONLY:
if (auth_opts->force_command != NULL) {
2003-04-09 12:59:48 +02:00
logit("Root login accepted for forced command.");
return 1;
}
break;
}
logit("ROOT LOGIN REFUSED FROM %.200s port %d",
ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
return 0;
}
/*
* Given a template and a passwd structure, build a filename
* by substituting % tokenised options. Currently, %% becomes '%',
* %h becomes the home directory and %u the username.
*
* This returns a buffer allocated by xmalloc.
*/
char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
char *file, uidstr[32], ret[PATH_MAX];
int i;
snprintf(uidstr, sizeof(uidstr), "%llu",
(unsigned long long)pw->pw_uid);
file = percent_expand(filename, "h", pw->pw_dir,
"u", pw->pw_name, "U", uidstr, (char *)NULL);
/*
* Ensure that filename starts anchored. If not, be backward
* compatible and prepend the '%h/'
*/
if (path_absolute(file))
return (file);
i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
if (i < 0 || (size_t)i >= sizeof(ret))
fatal("expand_authorized_keys: path too long");
free(file);
return (xstrdup(ret));
}
char *
authorized_principals_file(struct passwd *pw)
{
if (options.authorized_principals_file == NULL)
return NULL;
return expand_authorized_keys(options.authorized_principals_file, pw);
}
/* return ok if key exists in sysfile or userfile */
HostStatus
check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
const char *sysfile, const char *userfile)
{
char *user_hostfile;
struct stat st;
HostStatus host_status;
struct hostkeys *hostkeys;
const struct hostkey_entry *found;
hostkeys = init_hostkeys();
load_hostkeys(hostkeys, host, sysfile);
if (userfile != NULL) {
user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
if (options.strict_modes &&
(stat(user_hostfile, &st) == 0) &&
((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
(st.st_mode & 022) != 0)) {
2003-04-09 12:59:48 +02:00
logit("Authentication refused for %.100s: "
"bad owner or modes for %.200s",
pw->pw_name, user_hostfile);
auth_debug_add("Ignored %.200s: bad ownership or modes",
user_hostfile);
} else {
temporarily_use_uid(pw);
load_hostkeys(hostkeys, host, user_hostfile);
restore_uid();
}
free(user_hostfile);
}
host_status = check_key_in_hostkeys(hostkeys, key, &found);
if (host_status == HOST_REVOKED)
error("WARNING: revoked key for %s attempted authentication",
found->host);
else if (host_status == HOST_OK)
debug("%s: key for %s found at %s:%ld", __func__,
found->host, found->file, found->line);
else
debug("%s: key for host %s not found", __func__, host);
free_hostkeys(hostkeys);
return host_status;
}
static FILE *
auth_openfile(const char *file, struct passwd *pw, int strict_modes,
int log_missing, char *file_type)
{
char line[1024];
struct stat st;
int fd;
FILE *f;
if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
if (log_missing || errno != ENOENT)
debug("Could not open %s '%s': %s", file_type, file,
strerror(errno));
return NULL;
}
if (fstat(fd, &st) < 0) {
close(fd);
return NULL;
}
if (!S_ISREG(st.st_mode)) {
logit("User %s %s %s is not a regular file",
pw->pw_name, file_type, file);
close(fd);
return NULL;
}
unset_nonblock(fd);
if ((f = fdopen(fd, "r")) == NULL) {
close(fd);
return NULL;
}
if (strict_modes &&
safe_path_fd(fileno(f), file, pw, line, sizeof(line)) != 0) {
fclose(f);
logit("Authentication refused: %s", line);
auth_debug_add("Ignored %s: %s", file_type, line);
return NULL;
}
return f;
}
FILE *
auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
{
return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
}
FILE *
auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
{
return auth_openfile(file, pw, strict_modes, 0,
"authorized principals");
}
struct passwd *
getpwnamallow(const char *user)
{
struct ssh *ssh = active_state; /* XXX */
#ifdef HAVE_LOGIN_CAP
extern login_cap_t *lc;
#ifdef BSD_AUTH
auth_session_t *as;
#endif
#endif
struct passwd *pw;
struct connection_info *ci;
ci = get_connection_info(ssh, 1, options.use_dns);
ci->user = user;
parse_server_match_config(&options, ci);
log_change_level(options.log_level);
process_permitopen(ssh, &options);
#if defined(_AIX) && defined(HAVE_SETAUTHDB)
aix_setauthdb(user);
#endif
pw = getpwnam(user);
#if defined(_AIX) && defined(HAVE_SETAUTHDB)
aix_restoreauthdb();
#endif
#ifdef HAVE_CYGWIN
/*
* Windows usernames are case-insensitive. To avoid later problems
* when trying to match the username, the user is only allowed to
* login if the username is given in the same case as stored in the
* user database.
*/
if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
logit("Login name %.100s does not match stored username %.100s",
user, pw->pw_name);
pw = NULL;
}
#endif
if (pw == NULL) {
logit("Invalid user %.100s from %.100s port %d",
user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
#ifdef CUSTOM_FAILED_LOGIN
record_failed_login(user,
auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
audit_event(SSH_INVALID_USER);
#endif /* SSH_AUDIT_EVENTS */
return (NULL);
}
if (!allowed_user(pw))
return (NULL);
#ifdef HAVE_LOGIN_CAP
if ((lc = login_getclass(pw->pw_class)) == NULL) {
debug("unable to get login class: %s", user);
return (NULL);
}
#ifdef BSD_AUTH
if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
2002-05-22 06:04:11 +02:00
auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
debug("Approval failure for %s", user);
pw = NULL;
}
if (as != NULL)
auth_close(as);
#endif
#endif
if (pw != NULL)
return (pwcopy(pw));
return (NULL);
}
/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
int
auth_key_is_revoked(struct sshkey *key)
{
char *fp = NULL;
int r;
if (options.revoked_keys_file == NULL)
return 0;
if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
error("%s: fingerprint key: %s", __func__, ssh_err(r));
goto out;
}
r = sshkey_check_revoked(key, options.revoked_keys_file);
switch (r) {
case 0:
break; /* not revoked */
case SSH_ERR_KEY_REVOKED:
error("Authentication key %s %s revoked by file %s",
sshkey_type(key), fp, options.revoked_keys_file);
goto out;
default:
error("Error checking authentication key %s %s in "
"revoked keys file %s: %s", sshkey_type(key), fp,
options.revoked_keys_file, ssh_err(r));
goto out;
}
/* Success */
r = 0;
out:
free(fp);
return r == 0 ? 0 : 1;
}
void
auth_debug_add(const char *fmt,...)
{
char buf[1024];
va_list args;
int r;
if (auth_debug == NULL)
return;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0)
fatal("%s: sshbuf_put_cstring: %s", __func__, ssh_err(r));
}
void
auth_debug_send(void)
{
struct ssh *ssh = active_state; /* XXX */
char *msg;
int r;
if (auth_debug == NULL)
return;
while (sshbuf_len(auth_debug) != 0) {
if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0)
fatal("%s: sshbuf_get_cstring: %s",
__func__, ssh_err(r));
ssh_packet_send_debug(ssh, "%s", msg);
free(msg);
}
}
void
auth_debug_reset(void)
{
if (auth_debug != NULL)
sshbuf_reset(auth_debug);
else if ((auth_debug = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
}
struct passwd *
fakepw(void)
{
static struct passwd fake;
memset(&fake, 0, sizeof(fake));
fake.pw_name = "NOUSER";
fake.pw_passwd =
2003-11-21 13:56:47 +01:00
"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
fake.pw_gecos = "NOUSER";
#endif
fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
fake.pw_class = "";
#endif
fake.pw_dir = "/nonexist";
fake.pw_shell = "/nonexist";
return (&fake);
}
/*
* Returns the remote DNS hostname as a string. The returned string must not
* be freed. NB. this will usually trigger a DNS query the first time it is
* called.
* This function does additional checks on the hostname to mitigate some
* attacks on legacy rhosts-style authentication.
* XXX is RhostsRSAAuthentication vulnerable to these?
* XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
*/
static char *
remote_hostname(struct ssh *ssh)
{
struct sockaddr_storage from;
socklen_t fromlen;
struct addrinfo hints, *ai, *aitop;
char name[NI_MAXHOST], ntop2[NI_MAXHOST];
const char *ntop = ssh_remote_ipaddr(ssh);
/* Get IP address of client. */
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (getpeername(ssh_packet_get_connection_in(ssh),
(struct sockaddr *)&from, &fromlen) < 0) {
debug("getpeername failed: %.100s", strerror(errno));
return strdup(ntop);
}
ipv64_normalise_mapped(&from, &fromlen);
if (from.ss_family == AF_INET6)
fromlen = sizeof(struct sockaddr_in6);
debug3("Trying to reverse map address %.100s.", ntop);
/* Map the IP address to a host name. */
if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
NULL, 0, NI_NAMEREQD) != 0) {
/* Host name not found. Use ip address. */
return strdup(ntop);
}
/*
* if reverse lookup result looks like a numeric hostname,
* someone is trying to trick us by PTR record like following:
* 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
*/
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
hints.ai_flags = AI_NUMERICHOST;
if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
name, ntop);
freeaddrinfo(ai);
return strdup(ntop);
}
/* Names are stored in lowercase. */
lowercase(name);
/*
* Map it back to an IP address and check that the given
* address actually is an address of this host. This is
* necessary because anyone with access to a name server can
* define arbitrary names for an IP address. Mapping from
* name to IP address can be trusted better (but can still be
* fooled if the intruder has access to the name server of
* the domain).
*/
memset(&hints, 0, sizeof(hints));
hints.ai_family = from.ss_family;
hints.ai_socktype = SOCK_STREAM;
if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
logit("reverse mapping checking getaddrinfo for %.700s "
"[%s] failed.", name, ntop);
return strdup(ntop);
}
/* Look for the address from the list of addresses. */
for (ai = aitop; ai; ai = ai->ai_next) {
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
(strcmp(ntop, ntop2) == 0))
break;
}
freeaddrinfo(aitop);
/* If we reached the end of the list, the address was not there. */
if (ai == NULL) {
/* Address not found for the host name. */
logit("Address %.100s maps to %.600s, but this does not "
"map back to the address.", ntop, name);
return strdup(ntop);
}
return strdup(name);
}
/*
* Return the canonical name of the host in the other side of the current
* connection. The host name is cached, so it is efficient to call this
* several times.
*/
const char *
auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
{
static char *dnsname;
if (!use_dns)
return ssh_remote_ipaddr(ssh);
else if (dnsname != NULL)
return dnsname;
else {
dnsname = remote_hostname(ssh);
return dnsname;
}
}
/*
* Runs command in a subprocess with a minimal environment.
* Returns pid on success, 0 on failure.
* The child stdout and stderr maybe captured, left attached or sent to
* /dev/null depending on the contents of flags.
* "tag" is prepended to log messages.
* NB. "command" is only used for logging; the actual command executed is
* av[0].
*/
pid_t
subprocess(const char *tag, struct passwd *pw, const char *command,
int ac, char **av, FILE **child, u_int flags)
{
FILE *f = NULL;
struct stat st;
int fd, devnull, p[2], i;
pid_t pid;
char *cp, errmsg[512];
u_int envsize;
char **child_env;
if (child != NULL)
*child = NULL;
debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
tag, command, pw->pw_name, flags);
/* Check consistency */
if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
(flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
error("%s: inconsistent flags", __func__);
return 0;
}
if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
error("%s: inconsistent flags/output", __func__);
return 0;
}
/*
* If executing an explicit binary, then verify the it exists
* and appears safe-ish to execute
*/
if (!path_absolute(av[0])) {
error("%s path is not absolute", tag);
return 0;
}
temporarily_use_uid(pw);
if (stat(av[0], &st) < 0) {
error("Could not stat %s \"%s\": %s", tag,
av[0], strerror(errno));
restore_uid();
return 0;
}
if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
restore_uid();
return 0;
}
/* Prepare to keep the child's stdout if requested */
if (pipe(p) != 0) {
error("%s: pipe: %s", tag, strerror(errno));
restore_uid();
return 0;
}
restore_uid();
switch ((pid = fork())) {
case -1: /* error */
error("%s: fork: %s", tag, strerror(errno));
close(p[0]);
close(p[1]);
return 0;
case 0: /* child */
/* Prepare a minimal environment for the child. */
envsize = 5;
child_env = xcalloc(sizeof(*child_env), envsize);
child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
child_set_env(&child_env, &envsize, "USER", pw->pw_name);
child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
if ((cp = getenv("LANG")) != NULL)
child_set_env(&child_env, &envsize, "LANG", cp);
for (i = 0; i < NSIG; i++)
signal(i, SIG_DFL);
if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
error("%s: open %s: %s", tag, _PATH_DEVNULL,
strerror(errno));
_exit(1);
}
if (dup2(devnull, STDIN_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
/* Set up stdout as requested; leave stderr in place for now. */
fd = -1;
if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
fd = p[1];
else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
fd = devnull;
if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
closefrom(STDERR_FILENO + 1);
/* Don't use permanently_set_uid() here to avoid fatal() */
if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
strerror(errno));
_exit(1);
}
if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
strerror(errno));
_exit(1);
}
/* stdin is pointed to /dev/null at this point */
if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
execve(av[0], av, child_env);
error("%s exec \"%s\": %s", tag, command, strerror(errno));
_exit(127);
default: /* parent */
break;
}
close(p[1]);
if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
close(p[0]);
else if ((f = fdopen(p[0], "r")) == NULL) {
error("%s: fdopen: %s", tag, strerror(errno));
close(p[0]);
/* Don't leave zombie child */
kill(pid, SIGTERM);
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
;
return 0;
}
/* Success */
debug3("%s: %s pid %ld", __func__, tag, (long)pid);
if (child != NULL)
*child = f;
return pid;
}
/* These functions link key/cert options to the auth framework */
/* Log sshauthopt options locally and (optionally) for remote transmission */
void
auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote)
{
int do_env = options.permit_user_env && opts->nenv > 0;
int do_permitopen = opts->npermitopen > 0 &&
(options.allow_tcp_forwarding & FORWARD_LOCAL) != 0;
int do_permitlisten = opts->npermitlisten > 0 &&
(options.allow_tcp_forwarding & FORWARD_REMOTE) != 0;
size_t i;
char msg[1024], buf[64];
snprintf(buf, sizeof(buf), "%d", opts->force_tun_device);
/* Try to keep this alphabetically sorted */
snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s",
opts->permit_agent_forwarding_flag ? " agent-forwarding" : "",
opts->force_command == NULL ? "" : " command",
do_env ? " environment" : "",
opts->valid_before == 0 ? "" : "expires",
do_permitopen ? " permitopen" : "",
do_permitlisten ? " permitlisten" : "",
opts->permit_port_forwarding_flag ? " port-forwarding" : "",
opts->cert_principals == NULL ? "" : " principals",
opts->permit_pty_flag ? " pty" : "",
opts->force_tun_device == -1 ? "" : " tun=",
opts->force_tun_device == -1 ? "" : buf,
opts->permit_user_rc ? " user-rc" : "",
opts->permit_x11_forwarding_flag ? " x11-forwarding" : "");
debug("%s: %s", loc, msg);
if (do_remote)
auth_debug_add("%s: %s", loc, msg);
if (options.permit_user_env) {
for (i = 0; i < opts->nenv; i++) {
debug("%s: environment: %s", loc, opts->env[i]);
if (do_remote) {
auth_debug_add("%s: environment: %s",
loc, opts->env[i]);
}
}
}
/* Go into a little more details for the local logs. */
if (opts->valid_before != 0) {
format_absolute_time(opts->valid_before, buf, sizeof(buf));
debug("%s: expires at %s", loc, buf);
}
if (opts->cert_principals != NULL) {
debug("%s: authorized principals: \"%s\"",
loc, opts->cert_principals);
}
if (opts->force_command != NULL)
debug("%s: forced command: \"%s\"", loc, opts->force_command);
if (do_permitopen) {
for (i = 0; i < opts->npermitopen; i++) {
debug("%s: permitted open: %s",
loc, opts->permitopen[i]);
}
}
if (do_permitlisten) {
for (i = 0; i < opts->npermitlisten; i++) {
debug("%s: permitted listen: %s",
loc, opts->permitlisten[i]);
}
}
}
/* Activate a new set of key/cert options; merging with what is there. */
int
auth_activate_options(struct ssh *ssh, struct sshauthopt *opts)
{
struct sshauthopt *old = auth_opts;
const char *emsg = NULL;
debug("%s: setting new authentication options", __func__);
if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) {
error("Inconsistent authentication options: %s", emsg);
return -1;
}
return 0;
}
/* Disable forwarding, etc for the session */
void
auth_restrict_session(struct ssh *ssh)
{
struct sshauthopt *restricted;
debug("%s: restricting session", __func__);
/* A blank sshauthopt defaults to permitting nothing */
restricted = sshauthopt_new();
restricted->permit_pty_flag = 1;
restricted->restricted = 1;
if (auth_activate_options(ssh, restricted) != 0)
fatal("%s: failed to restrict session", __func__);
sshauthopt_free(restricted);
}
int
auth_authorise_keyopts(struct ssh *ssh, struct passwd *pw,
struct sshauthopt *opts, int allow_cert_authority, const char *loc)
{
const char *remote_ip = ssh_remote_ipaddr(ssh);
const char *remote_host = auth_get_canonical_hostname(ssh,
options.use_dns);
time_t now = time(NULL);
char buf[64];
/*
* Check keys/principals file expiry time.
* NB. validity interval in certificate is handled elsewhere.
*/
if (opts->valid_before && now > 0 &&
opts->valid_before < (uint64_t)now) {
format_absolute_time(opts->valid_before, buf, sizeof(buf));
debug("%s: entry expired at %s", loc, buf);
auth_debug_add("%s: entry expired at %s", loc, buf);
return -1;
}
/* Consistency checks */
if (opts->cert_principals != NULL && !opts->cert_authority) {
debug("%s: principals on non-CA key", loc);
auth_debug_add("%s: principals on non-CA key", loc);
/* deny access */
return -1;
}
/* cert-authority flag isn't valid in authorized_principals files */
if (!allow_cert_authority && opts->cert_authority) {
debug("%s: cert-authority flag invalid here", loc);
auth_debug_add("%s: cert-authority flag invalid here", loc);
/* deny access */
return -1;
}
/* Perform from= checks */
if (opts->required_from_host_keys != NULL) {
switch (match_host_and_ip(remote_host, remote_ip,
opts->required_from_host_keys )) {
case 1:
/* Host name matches. */
break;
case -1:
default:
debug("%s: invalid from criteria", loc);
auth_debug_add("%s: invalid from criteria", loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with "
"correct key but not from a permitted "
"host (host=%.200s, ip=%.200s, required=%.200s).",
loc, pw->pw_name, remote_host, remote_ip,
opts->required_from_host_keys);
auth_debug_add("%s: Your host '%.200s' is not "
"permitted to use this key for login.",
loc, remote_host);
/* deny access */
return -1;
}
}
/* Check source-address restriction from certificate */
if (opts->required_from_host_cert != NULL) {
switch (addr_match_cidr_list(remote_ip,
opts->required_from_host_cert)) {
case 1:
/* accepted */
break;
case -1:
default:
/* invalid */
error("%s: Certificate source-address invalid",
loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with valid "
"certificate but not from a permitted source "
"address (%.200s).", loc, pw->pw_name, remote_ip);
auth_debug_add("%s: Your address '%.200s' is not "
"permitted to use this certificate for login.",
loc, remote_ip);
return -1;
}
}
/*
*
* XXX this is spammy. We should report remotely only for keys
* that are successful in actual auth attempts, and not PK_OK
* tests.
*/
auth_log_authopts(loc, opts, 1);
return 0;
}