1116 lines
28 KiB
C
1116 lines
28 KiB
C
/*-
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* Copyright (c) 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by ThinkSec AS and
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* NAI Labs, the Security Research Division of Network Associates, Inc.
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* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
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* DARPA CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
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* Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/* Based on $FreeBSD$ */
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#include "includes.h"
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RCSID("$Id: auth-pam.c,v 1.114 2004/08/16 13:12:06 dtucker Exp $");
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#ifdef USE_PAM
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#if defined(HAVE_SECURITY_PAM_APPL_H)
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#include <security/pam_appl.h>
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#elif defined (HAVE_PAM_PAM_APPL_H)
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#include <pam/pam_appl.h>
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#endif
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#include "auth.h"
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#include "auth-pam.h"
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#include "buffer.h"
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#include "bufaux.h"
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#include "canohost.h"
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#include "log.h"
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#include "monitor_wrap.h"
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#include "msg.h"
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#include "packet.h"
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#include "misc.h"
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#include "servconf.h"
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#include "ssh2.h"
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#include "xmalloc.h"
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#include "auth-options.h"
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extern ServerOptions options;
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extern Buffer loginmsg;
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extern int compat20;
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extern u_int utmp_len;
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#ifdef USE_POSIX_THREADS
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#include <pthread.h>
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/*
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* Avoid namespace clash when *not* using pthreads for systems *with*
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* pthreads, which unconditionally define pthread_t via sys/types.h
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* (e.g. Linux)
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*/
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typedef pthread_t sp_pthread_t;
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#else
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typedef pid_t sp_pthread_t;
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#endif
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struct pam_ctxt {
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sp_pthread_t pam_thread;
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int pam_psock;
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int pam_csock;
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int pam_done;
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};
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static void sshpam_free_ctx(void *);
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static struct pam_ctxt *cleanup_ctxt;
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#ifndef USE_POSIX_THREADS
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/*
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* Simulate threads with processes.
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*/
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static int sshpam_thread_status = -1;
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static mysig_t sshpam_oldsig;
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static void
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sshpam_sigchld_handler(int sig)
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{
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signal(SIGCHLD, SIG_DFL);
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if (cleanup_ctxt == NULL)
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return; /* handler called after PAM cleanup, shouldn't happen */
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if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
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<= 0) {
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/* PAM thread has not exitted, privsep slave must have */
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kill(cleanup_ctxt->pam_thread, SIGTERM);
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if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
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<= 0)
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return; /* could not wait */
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}
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if (WIFSIGNALED(sshpam_thread_status) &&
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WTERMSIG(sshpam_thread_status) == SIGTERM)
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return; /* terminated by pthread_cancel */
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if (!WIFEXITED(sshpam_thread_status))
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fatal("PAM: authentication thread exited unexpectedly");
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if (WEXITSTATUS(sshpam_thread_status) != 0)
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fatal("PAM: authentication thread exited uncleanly");
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}
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static void
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pthread_exit(void *value __unused)
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{
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_exit(0);
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}
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static int
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pthread_create(sp_pthread_t *thread, const void *attr __unused,
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void *(*thread_start)(void *), void *arg)
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{
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pid_t pid;
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sshpam_thread_status = -1;
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switch ((pid = fork())) {
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case -1:
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error("fork(): %s", strerror(errno));
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return (-1);
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case 0:
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thread_start(arg);
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_exit(1);
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default:
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*thread = pid;
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sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
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return (0);
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}
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}
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static int
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pthread_cancel(sp_pthread_t thread)
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{
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signal(SIGCHLD, sshpam_oldsig);
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return (kill(thread, SIGTERM));
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}
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static int
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pthread_join(sp_pthread_t thread, void **value __unused)
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{
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int status;
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if (sshpam_thread_status != -1)
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return (sshpam_thread_status);
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signal(SIGCHLD, sshpam_oldsig);
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waitpid(thread, &status, 0);
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return (status);
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}
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#endif
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static pam_handle_t *sshpam_handle = NULL;
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static int sshpam_err = 0;
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static int sshpam_authenticated = 0;
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static int sshpam_session_open = 0;
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static int sshpam_cred_established = 0;
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static int sshpam_account_status = -1;
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static char **sshpam_env = NULL;
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static Authctxt *sshpam_authctxt = NULL;
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static const char *sshpam_password = NULL;
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/* Some PAM implementations don't implement this */
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#ifndef HAVE_PAM_GETENVLIST
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static char **
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pam_getenvlist(pam_handle_t *pamh)
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{
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/*
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* XXX - If necessary, we can still support envrionment passing
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* for platforms without pam_getenvlist by searching for known
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* env vars (e.g. KRB5CCNAME) from the PAM environment.
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*/
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return NULL;
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}
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#endif
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/*
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* Some platforms, notably Solaris, do not enforce password complexity
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* rules during pam_chauthtok() if the real uid of the calling process
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* is 0, on the assumption that it's being called by "passwd" run by root.
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* This wraps pam_chauthtok and sets/restore the real uid so PAM will do
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* the right thing.
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*/
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#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
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static int
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sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
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{
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int result;
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if (sshpam_authctxt == NULL)
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fatal("PAM: sshpam_authctxt not initialized");
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if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
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fatal("%s: setreuid failed: %s", __func__, strerror(errno));
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result = pam_chauthtok(pamh, flags);
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if (setreuid(0, -1) == -1)
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fatal("%s: setreuid failed: %s", __func__, strerror(errno));
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return result;
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}
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# define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
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#endif
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void
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sshpam_password_change_required(int reqd)
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{
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debug3("%s %d", __func__, reqd);
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if (sshpam_authctxt == NULL)
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fatal("%s: PAM authctxt not initialized", __func__);
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sshpam_authctxt->force_pwchange = reqd;
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if (reqd) {
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no_port_forwarding_flag |= 2;
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no_agent_forwarding_flag |= 2;
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no_x11_forwarding_flag |= 2;
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} else {
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no_port_forwarding_flag &= ~2;
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no_agent_forwarding_flag &= ~2;
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no_x11_forwarding_flag &= ~2;
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}
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}
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/* Import regular and PAM environment from subprocess */
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static void
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import_environments(Buffer *b)
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{
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char *env;
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u_int i, num_env;
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int err;
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debug3("PAM: %s entering", __func__);
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#ifndef USE_POSIX_THREADS
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/* Import variables set by do_pam_account */
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sshpam_account_status = buffer_get_int(b);
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sshpam_password_change_required(buffer_get_int(b));
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/* Import environment from subprocess */
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num_env = buffer_get_int(b);
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sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
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debug3("PAM: num env strings %d", num_env);
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for(i = 0; i < num_env; i++)
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sshpam_env[i] = buffer_get_string(b, NULL);
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sshpam_env[num_env] = NULL;
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/* Import PAM environment from subprocess */
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num_env = buffer_get_int(b);
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debug("PAM: num PAM env strings %d", num_env);
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for(i = 0; i < num_env; i++) {
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env = buffer_get_string(b, NULL);
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#ifdef HAVE_PAM_PUTENV
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/* Errors are not fatal here */
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if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
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error("PAM: pam_putenv: %s",
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pam_strerror(sshpam_handle, sshpam_err));
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}
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#endif
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}
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#endif
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}
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/*
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* Conversation function for authentication thread.
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*/
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static int
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sshpam_thread_conv(int n, struct pam_message **msg,
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struct pam_response **resp, void *data)
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{
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Buffer buffer;
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struct pam_ctxt *ctxt;
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struct pam_response *reply;
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int i;
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debug3("PAM: %s entering, %d messages", __func__, n);
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*resp = NULL;
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if (data == NULL) {
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error("PAM: conversation function passed a null context");
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return (PAM_CONV_ERR);
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}
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ctxt = data;
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if (n <= 0 || n > PAM_MAX_NUM_MSG)
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return (PAM_CONV_ERR);
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if ((reply = malloc(n * sizeof(*reply))) == NULL)
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return (PAM_CONV_ERR);
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memset(reply, 0, n * sizeof(*reply));
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buffer_init(&buffer);
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for (i = 0; i < n; ++i) {
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switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
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case PAM_PROMPT_ECHO_OFF:
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buffer_put_cstring(&buffer,
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PAM_MSG_MEMBER(msg, i, msg));
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if (ssh_msg_send(ctxt->pam_csock,
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PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
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goto fail;
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if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
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goto fail;
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if (buffer_get_char(&buffer) != PAM_AUTHTOK)
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goto fail;
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reply[i].resp = buffer_get_string(&buffer, NULL);
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break;
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case PAM_PROMPT_ECHO_ON:
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buffer_put_cstring(&buffer,
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PAM_MSG_MEMBER(msg, i, msg));
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if (ssh_msg_send(ctxt->pam_csock,
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PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
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goto fail;
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if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
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goto fail;
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if (buffer_get_char(&buffer) != PAM_AUTHTOK)
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goto fail;
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reply[i].resp = buffer_get_string(&buffer, NULL);
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break;
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case PAM_ERROR_MSG:
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buffer_put_cstring(&buffer,
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PAM_MSG_MEMBER(msg, i, msg));
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if (ssh_msg_send(ctxt->pam_csock,
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PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
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goto fail;
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break;
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case PAM_TEXT_INFO:
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buffer_put_cstring(&buffer,
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PAM_MSG_MEMBER(msg, i, msg));
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if (ssh_msg_send(ctxt->pam_csock,
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PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
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goto fail;
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break;
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default:
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goto fail;
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}
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buffer_clear(&buffer);
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}
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buffer_free(&buffer);
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*resp = reply;
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return (PAM_SUCCESS);
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fail:
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for(i = 0; i < n; i++) {
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if (reply[i].resp != NULL)
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xfree(reply[i].resp);
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}
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xfree(reply);
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buffer_free(&buffer);
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return (PAM_CONV_ERR);
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}
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/*
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* Authentication thread.
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*/
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static void *
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sshpam_thread(void *ctxtp)
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{
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struct pam_ctxt *ctxt = ctxtp;
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Buffer buffer;
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struct pam_conv sshpam_conv;
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int flags = (options.permit_empty_passwd == 0 ?
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PAM_DISALLOW_NULL_AUTHTOK : 0);
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#ifndef USE_POSIX_THREADS
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extern char **environ;
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char **env_from_pam;
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u_int i;
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const char *pam_user;
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pam_get_item(sshpam_handle, PAM_USER, (void **)&pam_user);
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environ[0] = NULL;
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if (sshpam_authctxt != NULL) {
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setproctitle("%s [pam]",
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sshpam_authctxt->valid ? pam_user : "unknown");
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}
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#endif
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sshpam_conv.conv = sshpam_thread_conv;
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sshpam_conv.appdata_ptr = ctxt;
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if (sshpam_authctxt == NULL)
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fatal("%s: PAM authctxt not initialized", __func__);
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|
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buffer_init(&buffer);
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sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
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(const void *)&sshpam_conv);
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if (sshpam_err != PAM_SUCCESS)
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goto auth_fail;
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sshpam_err = pam_authenticate(sshpam_handle, flags);
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if (sshpam_err != PAM_SUCCESS)
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goto auth_fail;
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|
|
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if (compat20) {
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if (!do_pam_account())
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goto auth_fail;
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if (sshpam_authctxt->force_pwchange) {
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sshpam_err = pam_chauthtok(sshpam_handle,
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PAM_CHANGE_EXPIRED_AUTHTOK);
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if (sshpam_err != PAM_SUCCESS)
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goto auth_fail;
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sshpam_password_change_required(0);
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}
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}
|
|
|
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buffer_put_cstring(&buffer, "OK");
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|
|
|
#ifndef USE_POSIX_THREADS
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/* Export variables set by do_pam_account */
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buffer_put_int(&buffer, sshpam_account_status);
|
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buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
|
|
|
|
/* Export any environment strings set in child */
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for(i = 0; environ[i] != NULL; i++)
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; /* Count */
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buffer_put_int(&buffer, i);
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for(i = 0; environ[i] != NULL; i++)
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buffer_put_cstring(&buffer, environ[i]);
|
|
|
|
/* Export any environment strings set by PAM in child */
|
|
env_from_pam = pam_getenvlist(sshpam_handle);
|
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for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
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; /* Count */
|
|
buffer_put_int(&buffer, i);
|
|
for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
|
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buffer_put_cstring(&buffer, env_from_pam[i]);
|
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#endif /* USE_POSIX_THREADS */
|
|
|
|
/* XXX - can't do much about an error here */
|
|
ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
|
|
buffer_free(&buffer);
|
|
pthread_exit(NULL);
|
|
|
|
auth_fail:
|
|
buffer_put_cstring(&buffer,
|
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pam_strerror(sshpam_handle, sshpam_err));
|
|
/* XXX - can't do much about an error here */
|
|
ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
|
|
buffer_free(&buffer);
|
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pthread_exit(NULL);
|
|
|
|
return (NULL); /* Avoid warning for non-pthread case */
|
|
}
|
|
|
|
void
|
|
sshpam_thread_cleanup(void)
|
|
{
|
|
struct pam_ctxt *ctxt = cleanup_ctxt;
|
|
|
|
debug3("PAM: %s entering", __func__);
|
|
if (ctxt != NULL && ctxt->pam_thread != 0) {
|
|
pthread_cancel(ctxt->pam_thread);
|
|
pthread_join(ctxt->pam_thread, NULL);
|
|
close(ctxt->pam_psock);
|
|
close(ctxt->pam_csock);
|
|
memset(ctxt, 0, sizeof(*ctxt));
|
|
cleanup_ctxt = NULL;
|
|
}
|
|
}
|
|
|
|
static int
|
|
sshpam_null_conv(int n, struct pam_message **msg,
|
|
struct pam_response **resp, void *data)
|
|
{
|
|
debug3("PAM: %s entering, %d messages", __func__, n);
|
|
return (PAM_CONV_ERR);
|
|
}
|
|
|
|
static struct pam_conv null_conv = { sshpam_null_conv, NULL };
|
|
|
|
void
|
|
sshpam_cleanup(void)
|
|
{
|
|
debug("PAM: cleanup");
|
|
if (sshpam_handle == NULL)
|
|
return;
|
|
pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
|
|
if (sshpam_cred_established) {
|
|
pam_setcred(sshpam_handle, PAM_DELETE_CRED);
|
|
sshpam_cred_established = 0;
|
|
}
|
|
if (sshpam_session_open) {
|
|
pam_close_session(sshpam_handle, PAM_SILENT);
|
|
sshpam_session_open = 0;
|
|
}
|
|
sshpam_authenticated = 0;
|
|
pam_end(sshpam_handle, sshpam_err);
|
|
sshpam_handle = NULL;
|
|
}
|
|
|
|
static int
|
|
sshpam_init(Authctxt *authctxt)
|
|
{
|
|
extern char *__progname;
|
|
const char *pam_rhost, *pam_user, *user = authctxt->user;
|
|
|
|
if (sshpam_handle != NULL) {
|
|
/* We already have a PAM context; check if the user matches */
|
|
sshpam_err = pam_get_item(sshpam_handle,
|
|
PAM_USER, (void **)&pam_user);
|
|
if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
|
|
return (0);
|
|
pam_end(sshpam_handle, sshpam_err);
|
|
sshpam_handle = NULL;
|
|
}
|
|
debug("PAM: initializing for \"%s\"", user);
|
|
sshpam_err =
|
|
pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
|
|
sshpam_authctxt = authctxt;
|
|
|
|
if (sshpam_err != PAM_SUCCESS) {
|
|
pam_end(sshpam_handle, sshpam_err);
|
|
sshpam_handle = NULL;
|
|
return (-1);
|
|
}
|
|
pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
|
|
debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
|
|
if (sshpam_err != PAM_SUCCESS) {
|
|
pam_end(sshpam_handle, sshpam_err);
|
|
sshpam_handle = NULL;
|
|
return (-1);
|
|
}
|
|
#ifdef PAM_TTY_KLUDGE
|
|
/*
|
|
* Some silly PAM modules (e.g. pam_time) require a TTY to operate.
|
|
* sshd doesn't set the tty until too late in the auth process and
|
|
* may not even set one (for tty-less connections)
|
|
*/
|
|
debug("PAM: setting PAM_TTY to \"ssh\"");
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
|
|
if (sshpam_err != PAM_SUCCESS) {
|
|
pam_end(sshpam_handle, sshpam_err);
|
|
sshpam_handle = NULL;
|
|
return (-1);
|
|
}
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
static void *
|
|
sshpam_init_ctx(Authctxt *authctxt)
|
|
{
|
|
struct pam_ctxt *ctxt;
|
|
int socks[2];
|
|
|
|
debug3("PAM: %s entering", __func__);
|
|
/* Refuse to start if we don't have PAM enabled */
|
|
if (!options.use_pam)
|
|
return NULL;
|
|
|
|
/* Initialize PAM */
|
|
if (sshpam_init(authctxt) == -1) {
|
|
error("PAM: initialization failed");
|
|
return (NULL);
|
|
}
|
|
|
|
ctxt = xmalloc(sizeof *ctxt);
|
|
memset(ctxt, 0, sizeof(*ctxt));
|
|
|
|
/* Start the authentication thread */
|
|
if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
|
|
error("PAM: failed create sockets: %s", strerror(errno));
|
|
xfree(ctxt);
|
|
return (NULL);
|
|
}
|
|
ctxt->pam_psock = socks[0];
|
|
ctxt->pam_csock = socks[1];
|
|
if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
|
|
error("PAM: failed to start authentication thread: %s",
|
|
strerror(errno));
|
|
close(socks[0]);
|
|
close(socks[1]);
|
|
xfree(ctxt);
|
|
return (NULL);
|
|
}
|
|
cleanup_ctxt = ctxt;
|
|
return (ctxt);
|
|
}
|
|
|
|
static int
|
|
sshpam_query(void *ctx, char **name, char **info,
|
|
u_int *num, char ***prompts, u_int **echo_on)
|
|
{
|
|
Buffer buffer;
|
|
struct pam_ctxt *ctxt = ctx;
|
|
size_t plen;
|
|
u_char type;
|
|
char *msg;
|
|
size_t len;
|
|
|
|
debug3("PAM: %s entering", __func__);
|
|
buffer_init(&buffer);
|
|
*name = xstrdup("");
|
|
*info = xstrdup("");
|
|
*prompts = xmalloc(sizeof(char *));
|
|
**prompts = NULL;
|
|
plen = 0;
|
|
*echo_on = xmalloc(sizeof(u_int));
|
|
while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
|
|
type = buffer_get_char(&buffer);
|
|
msg = buffer_get_string(&buffer, NULL);
|
|
switch (type) {
|
|
case PAM_PROMPT_ECHO_ON:
|
|
case PAM_PROMPT_ECHO_OFF:
|
|
*num = 1;
|
|
len = plen + strlen(msg) + 1;
|
|
**prompts = xrealloc(**prompts, len);
|
|
plen += snprintf(**prompts + plen, len, "%s", msg);
|
|
**echo_on = (type == PAM_PROMPT_ECHO_ON);
|
|
xfree(msg);
|
|
return (0);
|
|
case PAM_ERROR_MSG:
|
|
case PAM_TEXT_INFO:
|
|
/* accumulate messages */
|
|
len = plen + strlen(msg) + 2;
|
|
**prompts = xrealloc(**prompts, len);
|
|
plen += snprintf(**prompts + plen, len, "%s\n", msg);
|
|
xfree(msg);
|
|
break;
|
|
case PAM_SUCCESS:
|
|
case PAM_AUTH_ERR:
|
|
if (**prompts != NULL) {
|
|
/* drain any accumulated messages */
|
|
debug("PAM: %s", **prompts);
|
|
buffer_append(&loginmsg, **prompts,
|
|
strlen(**prompts));
|
|
xfree(**prompts);
|
|
**prompts = NULL;
|
|
}
|
|
if (type == PAM_SUCCESS) {
|
|
import_environments(&buffer);
|
|
*num = 0;
|
|
**echo_on = 0;
|
|
ctxt->pam_done = 1;
|
|
xfree(msg);
|
|
return (0);
|
|
}
|
|
error("PAM: %s for %s%.100s from %.100s", msg,
|
|
sshpam_authctxt->valid ? "" : "illegal user ",
|
|
sshpam_authctxt->user,
|
|
get_remote_name_or_ip(utmp_len, options.use_dns));
|
|
/* FALLTHROUGH */
|
|
default:
|
|
*num = 0;
|
|
**echo_on = 0;
|
|
xfree(msg);
|
|
ctxt->pam_done = -1;
|
|
return (-1);
|
|
}
|
|
}
|
|
return (-1);
|
|
}
|
|
|
|
/* XXX - see also comment in auth-chall.c:verify_response */
|
|
static int
|
|
sshpam_respond(void *ctx, u_int num, char **resp)
|
|
{
|
|
Buffer buffer;
|
|
struct pam_ctxt *ctxt = ctx;
|
|
|
|
debug2("PAM: %s entering, %d responses", __func__, num);
|
|
switch (ctxt->pam_done) {
|
|
case 1:
|
|
sshpam_authenticated = 1;
|
|
return (0);
|
|
case 0:
|
|
break;
|
|
default:
|
|
return (-1);
|
|
}
|
|
if (num != 1) {
|
|
error("PAM: expected one response, got %u", num);
|
|
return (-1);
|
|
}
|
|
buffer_init(&buffer);
|
|
buffer_put_cstring(&buffer, *resp);
|
|
if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
|
|
buffer_free(&buffer);
|
|
return (-1);
|
|
}
|
|
buffer_free(&buffer);
|
|
return (1);
|
|
}
|
|
|
|
static void
|
|
sshpam_free_ctx(void *ctxtp)
|
|
{
|
|
struct pam_ctxt *ctxt = ctxtp;
|
|
|
|
debug3("PAM: %s entering", __func__);
|
|
sshpam_thread_cleanup();
|
|
xfree(ctxt);
|
|
/*
|
|
* We don't call sshpam_cleanup() here because we may need the PAM
|
|
* handle at a later stage, e.g. when setting up a session. It's
|
|
* still on the cleanup list, so pam_end() *will* be called before
|
|
* the server process terminates.
|
|
*/
|
|
}
|
|
|
|
KbdintDevice sshpam_device = {
|
|
"pam",
|
|
sshpam_init_ctx,
|
|
sshpam_query,
|
|
sshpam_respond,
|
|
sshpam_free_ctx
|
|
};
|
|
|
|
KbdintDevice mm_sshpam_device = {
|
|
"pam",
|
|
mm_sshpam_init_ctx,
|
|
mm_sshpam_query,
|
|
mm_sshpam_respond,
|
|
mm_sshpam_free_ctx
|
|
};
|
|
|
|
/*
|
|
* This replaces auth-pam.c
|
|
*/
|
|
void
|
|
start_pam(Authctxt *authctxt)
|
|
{
|
|
if (!options.use_pam)
|
|
fatal("PAM: initialisation requested when UsePAM=no");
|
|
|
|
if (sshpam_init(authctxt) == -1)
|
|
fatal("PAM: initialisation failed");
|
|
}
|
|
|
|
void
|
|
finish_pam(void)
|
|
{
|
|
sshpam_cleanup();
|
|
}
|
|
|
|
u_int
|
|
do_pam_account(void)
|
|
{
|
|
if (sshpam_account_status != -1)
|
|
return (sshpam_account_status);
|
|
|
|
sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
|
|
debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
|
|
|
|
if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
|
|
sshpam_account_status = 0;
|
|
return (sshpam_account_status);
|
|
}
|
|
|
|
if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
|
|
sshpam_password_change_required(1);
|
|
|
|
sshpam_account_status = 1;
|
|
return (sshpam_account_status);
|
|
}
|
|
|
|
void
|
|
do_pam_set_tty(const char *tty)
|
|
{
|
|
if (tty != NULL) {
|
|
debug("PAM: setting PAM_TTY to \"%s\"", tty);
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: failed to set PAM_TTY: %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
}
|
|
}
|
|
|
|
void
|
|
do_pam_setcred(int init)
|
|
{
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
|
|
(const void *)&null_conv);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: failed to set PAM_CONV: %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
if (init) {
|
|
debug("PAM: establishing credentials");
|
|
sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
|
|
} else {
|
|
debug("PAM: reinitializing credentials");
|
|
sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
|
|
}
|
|
if (sshpam_err == PAM_SUCCESS) {
|
|
sshpam_cred_established = 1;
|
|
return;
|
|
}
|
|
if (sshpam_authenticated)
|
|
fatal("PAM: pam_setcred(): %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
else
|
|
debug("PAM: pam_setcred(): %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
}
|
|
|
|
static int
|
|
sshpam_tty_conv(int n, struct pam_message **msg,
|
|
struct pam_response **resp, void *data)
|
|
{
|
|
char input[PAM_MAX_MSG_SIZE];
|
|
struct pam_response *reply;
|
|
int i;
|
|
|
|
debug3("PAM: %s called with %d messages", __func__, n);
|
|
|
|
*resp = NULL;
|
|
|
|
if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
|
|
return (PAM_CONV_ERR);
|
|
|
|
if ((reply = malloc(n * sizeof(*reply))) == NULL)
|
|
return (PAM_CONV_ERR);
|
|
memset(reply, 0, n * sizeof(*reply));
|
|
|
|
for (i = 0; i < n; ++i) {
|
|
switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
|
|
case PAM_PROMPT_ECHO_OFF:
|
|
reply[i].resp =
|
|
read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
|
|
RP_ALLOW_STDIN);
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
case PAM_PROMPT_ECHO_ON:
|
|
fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
|
|
fgets(input, sizeof input, stdin);
|
|
if ((reply[i].resp = strdup(input)) == NULL)
|
|
goto fail;
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
case PAM_ERROR_MSG:
|
|
case PAM_TEXT_INFO:
|
|
fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
default:
|
|
goto fail;
|
|
}
|
|
}
|
|
*resp = reply;
|
|
return (PAM_SUCCESS);
|
|
|
|
fail:
|
|
for(i = 0; i < n; i++) {
|
|
if (reply[i].resp != NULL)
|
|
xfree(reply[i].resp);
|
|
}
|
|
xfree(reply);
|
|
return (PAM_CONV_ERR);
|
|
}
|
|
|
|
static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
|
|
|
|
/*
|
|
* XXX this should be done in the authentication phase, but ssh1 doesn't
|
|
* support that
|
|
*/
|
|
void
|
|
do_pam_chauthtok(void)
|
|
{
|
|
if (use_privsep)
|
|
fatal("Password expired (unable to change with privsep)");
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
|
|
(const void *)&tty_conv);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: failed to set PAM_CONV: %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
debug("PAM: changing password");
|
|
sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: pam_chauthtok(): %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
}
|
|
|
|
static int
|
|
sshpam_store_conv(int n, struct pam_message **msg,
|
|
struct pam_response **resp, void *data)
|
|
{
|
|
struct pam_response *reply;
|
|
int i;
|
|
size_t len;
|
|
|
|
debug3("PAM: %s called with %d messages", __func__, n);
|
|
*resp = NULL;
|
|
|
|
if (n <= 0 || n > PAM_MAX_NUM_MSG)
|
|
return (PAM_CONV_ERR);
|
|
|
|
if ((reply = malloc(n * sizeof(*reply))) == NULL)
|
|
return (PAM_CONV_ERR);
|
|
memset(reply, 0, n * sizeof(*reply));
|
|
|
|
for (i = 0; i < n; ++i) {
|
|
switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
|
|
case PAM_ERROR_MSG:
|
|
case PAM_TEXT_INFO:
|
|
len = strlen(PAM_MSG_MEMBER(msg, i, msg));
|
|
buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
|
|
buffer_append(&loginmsg, "\n", 1 );
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
default:
|
|
goto fail;
|
|
}
|
|
}
|
|
*resp = reply;
|
|
return (PAM_SUCCESS);
|
|
|
|
fail:
|
|
for(i = 0; i < n; i++) {
|
|
if (reply[i].resp != NULL)
|
|
xfree(reply[i].resp);
|
|
}
|
|
xfree(reply);
|
|
return (PAM_CONV_ERR);
|
|
}
|
|
|
|
static struct pam_conv store_conv = { sshpam_store_conv, NULL };
|
|
|
|
void
|
|
do_pam_session(void)
|
|
{
|
|
debug3("PAM: opening session");
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
|
|
(const void *)&store_conv);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: failed to set PAM_CONV: %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
sshpam_err = pam_open_session(sshpam_handle, 0);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: pam_open_session(): %s",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
sshpam_session_open = 1;
|
|
}
|
|
|
|
/*
|
|
* Set a PAM environment string. We need to do this so that the session
|
|
* modules can handle things like Kerberos/GSI credentials that appear
|
|
* during the ssh authentication process.
|
|
*/
|
|
int
|
|
do_pam_putenv(char *name, char *value)
|
|
{
|
|
int ret = 1;
|
|
#ifdef HAVE_PAM_PUTENV
|
|
char *compound;
|
|
size_t len;
|
|
|
|
len = strlen(name) + strlen(value) + 2;
|
|
compound = xmalloc(len);
|
|
|
|
snprintf(compound, len, "%s=%s", name, value);
|
|
ret = pam_putenv(sshpam_handle, compound);
|
|
xfree(compound);
|
|
#endif
|
|
|
|
return (ret);
|
|
}
|
|
|
|
char **
|
|
fetch_pam_child_environment(void)
|
|
{
|
|
return sshpam_env;
|
|
}
|
|
|
|
char **
|
|
fetch_pam_environment(void)
|
|
{
|
|
return (pam_getenvlist(sshpam_handle));
|
|
}
|
|
|
|
void
|
|
free_pam_environment(char **env)
|
|
{
|
|
char **envp;
|
|
|
|
if (env == NULL)
|
|
return;
|
|
|
|
for (envp = env; *envp; envp++)
|
|
xfree(*envp);
|
|
xfree(env);
|
|
}
|
|
|
|
/*
|
|
* "Blind" conversation function for password authentication. Assumes that
|
|
* echo-off prompts are for the password and stores messages for later
|
|
* display.
|
|
*/
|
|
static int
|
|
sshpam_passwd_conv(int n, struct pam_message **msg,
|
|
struct pam_response **resp, void *data)
|
|
{
|
|
struct pam_response *reply;
|
|
int i;
|
|
size_t len;
|
|
|
|
debug3("PAM: %s called with %d messages", __func__, n);
|
|
|
|
*resp = NULL;
|
|
|
|
if (n <= 0 || n > PAM_MAX_NUM_MSG)
|
|
return (PAM_CONV_ERR);
|
|
|
|
if ((reply = malloc(n * sizeof(*reply))) == NULL)
|
|
return (PAM_CONV_ERR);
|
|
memset(reply, 0, n * sizeof(*reply));
|
|
|
|
for (i = 0; i < n; ++i) {
|
|
switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
|
|
case PAM_PROMPT_ECHO_OFF:
|
|
if (sshpam_password == NULL)
|
|
goto fail;
|
|
if ((reply[i].resp = strdup(sshpam_password)) == NULL)
|
|
goto fail;
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
case PAM_ERROR_MSG:
|
|
case PAM_TEXT_INFO:
|
|
len = strlen(PAM_MSG_MEMBER(msg, i, msg));
|
|
if (len > 0) {
|
|
buffer_append(&loginmsg,
|
|
PAM_MSG_MEMBER(msg, i, msg), len);
|
|
buffer_append(&loginmsg, "\n", 1);
|
|
}
|
|
if ((reply[i].resp = strdup("")) == NULL)
|
|
goto fail;
|
|
reply[i].resp_retcode = PAM_SUCCESS;
|
|
break;
|
|
default:
|
|
goto fail;
|
|
}
|
|
}
|
|
*resp = reply;
|
|
return (PAM_SUCCESS);
|
|
|
|
fail:
|
|
for(i = 0; i < n; i++) {
|
|
if (reply[i].resp != NULL)
|
|
xfree(reply[i].resp);
|
|
}
|
|
xfree(reply);
|
|
return (PAM_CONV_ERR);
|
|
}
|
|
|
|
static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
|
|
|
|
/*
|
|
* Attempt password authentication via PAM
|
|
*/
|
|
int
|
|
sshpam_auth_passwd(Authctxt *authctxt, const char *password)
|
|
{
|
|
int flags = (options.permit_empty_passwd == 0 ?
|
|
PAM_DISALLOW_NULL_AUTHTOK : 0);
|
|
static char badpw[] = "\b\n\r\177INCORRECT";
|
|
|
|
if (!options.use_pam || sshpam_handle == NULL)
|
|
fatal("PAM: %s called when PAM disabled or failed to "
|
|
"initialise.", __func__);
|
|
|
|
sshpam_password = password;
|
|
sshpam_authctxt = authctxt;
|
|
|
|
/*
|
|
* If the user logging in is invalid, or is root but is not permitted
|
|
* by PermitRootLogin, use an invalid password to prevent leaking
|
|
* information via timing (eg if the PAM config has a delay on fail).
|
|
*/
|
|
if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
|
|
options.permit_root_login != PERMIT_YES))
|
|
sshpam_password = badpw;
|
|
|
|
sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
|
|
(const void *)&passwd_conv);
|
|
if (sshpam_err != PAM_SUCCESS)
|
|
fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
|
|
sshpam_err = pam_authenticate(sshpam_handle, flags);
|
|
sshpam_password = NULL;
|
|
if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
|
|
debug("PAM: password authentication accepted for %.100s",
|
|
authctxt->user);
|
|
return 1;
|
|
} else {
|
|
debug("PAM: password authentication failed for %.100s: %s",
|
|
authctxt->valid ? authctxt->user : "an illegal user",
|
|
pam_strerror(sshpam_handle, sshpam_err));
|
|
return 0;
|
|
}
|
|
}
|
|
#endif /* USE_PAM */
|