auth-pam.c - security/openssh-library - Rivoreo Source Code Repositories

 /*-
  * Copyright (c) 2002 Networks Associates Technology, Inc.
  * All rights reserved.
  *
  * This software was developed for the FreeBSD Project by ThinkSec AS and
  * NAI Labs, the Security Research Division of Network Associates, Inc.
  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
  * DARPA CHATS research program.
  *
  * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
  */

 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
 #include "includes.h"
 RCSID("$Id: auth-pam.c,v 1.76 2003/10/09 04:20:15 dtucker Exp $");

 #ifdef USE_PAM
 #include <security/pam_appl.h>

 #include "auth.h"
 #include "auth-pam.h"
 #include "buffer.h"
 #include "bufaux.h"
 #include "canohost.h"
 #include "log.h"
 #include "monitor_wrap.h"
 #include "msg.h"
 #include "packet.h"
 #include "readpass.h"
 #include "servconf.h"
 #include "ssh2.h"
 #include "xmalloc.h"
 #include "auth-options.h"

 extern ServerOptions options;

 #define __unused

 #ifdef USE_POSIX_THREADS
 #include <pthread.h>
 /*
  * Avoid namespace clash when *not* using pthreads for systems *with*
  * pthreads, which unconditionally define pthread_t via sys/types.h
  * (e.g. Linux)
  */
 typedef pthread_t sp_pthread_t;
 #else
 /*
  * Simulate threads with processes.
  */
 typedef pid_t sp_pthread_t;

 static void
 pthread_exit(void *value __unused)
 {
 	_exit(0);
 }

 static int
 pthread_create(sp_pthread_t *thread, const void *attr __unused,
     void *(*thread_start)(void *), void *arg)
 {
 	pid_t pid;

 	switch ((pid = fork())) {
 	case -1:
 		error("fork(): %s", strerror(errno));
 		return (-1);
 	case 0:
 		thread_start(arg);
 		_exit(1);
 	default:
 		*thread = pid;
 		return (0);
 	}
 }

 static int
 pthread_cancel(sp_pthread_t thread)
 {
 	return (kill(thread, SIGTERM));
 }

 static int
 pthread_join(sp_pthread_t thread, void **value __unused)
 {
 	int status;

 	waitpid(thread, &status, 0);
 	return (status);
 }
 #endif


 static pam_handle_t *sshpam_handle = NULL;
 static int sshpam_err = 0;
 static int sshpam_authenticated = 0;
 static int sshpam_new_authtok_reqd = 0;
 static int sshpam_session_open = 0;
 static int sshpam_cred_established = 0;

 struct pam_ctxt {
 	sp_pthread_t	 pam_thread;
 	int		 pam_psock;
 	int		 pam_csock;
 	int		 pam_done;
 };

 static void sshpam_free_ctx(void *);
 static struct pam_ctxt *cleanup_ctxt;

 /*
  * Conversation function for authentication thread.
  */
 static int
 sshpam_thread_conv(int n, const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
 	Buffer buffer;
 	struct pam_ctxt *ctxt;
 	struct pam_response *reply;
 	int i;

 	*resp = NULL;

 	ctxt = data;
 	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));

 	buffer_init(&buffer);
 	for (i = 0; i < n; ++i) {
 		switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 		case PAM_PROMPT_ECHO_OFF:
 			buffer_put_cstring(&buffer,
 			    PAM_MSG_MEMBER(msg, i, msg));
 			ssh_msg_send(ctxt->pam_csock,
 			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 			ssh_msg_recv(ctxt->pam_csock, &buffer);
 			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 				goto fail;
 			reply[i].resp = buffer_get_string(&buffer, NULL);
 			break;
 		case PAM_PROMPT_ECHO_ON:
 			buffer_put_cstring(&buffer,
 			    PAM_MSG_MEMBER(msg, i, msg));
 			ssh_msg_send(ctxt->pam_csock,
 			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 			ssh_msg_recv(ctxt->pam_csock, &buffer);
 			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 				goto fail;
 			reply[i].resp = buffer_get_string(&buffer, NULL);
 			break;
 		case PAM_ERROR_MSG:
 			buffer_put_cstring(&buffer,
 			    PAM_MSG_MEMBER(msg, i, msg));
 			ssh_msg_send(ctxt->pam_csock,
 			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 			break;
 		case PAM_TEXT_INFO:
 			buffer_put_cstring(&buffer,
 			    PAM_MSG_MEMBER(msg, i, msg));
 			ssh_msg_send(ctxt->pam_csock,
 			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 			break;
 		default:
 			goto fail;
 		}
 		buffer_clear(&buffer);
 	}
 	buffer_free(&buffer);
 	*resp = reply;
 	return (PAM_SUCCESS);

  fail:
 	for(i = 0; i < n; i++) {
 		if (reply[i].resp != NULL)
 			xfree(reply[i].resp);
 	}
 	xfree(reply);
 	buffer_free(&buffer);
 	return (PAM_CONV_ERR);
 }

 /*
  * Authentication thread.
  */
 static void *
 sshpam_thread(void *ctxtp)
 {
 	struct pam_ctxt *ctxt = ctxtp;
 	Buffer buffer;
 	struct pam_conv sshpam_conv;
 #ifndef USE_POSIX_THREADS
 	const char *pam_user;

 	pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 	setproctitle("%s [pam]", pam_user);
 #endif

 	sshpam_conv.conv = sshpam_thread_conv;
 	sshpam_conv.appdata_ptr = ctxt;

 	buffer_init(&buffer);
 	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 	    (const void *)&sshpam_conv);
 	if (sshpam_err != PAM_SUCCESS)
 		goto auth_fail;
 	sshpam_err = pam_authenticate(sshpam_handle, 0);
 	if (sshpam_err != PAM_SUCCESS)
 		goto auth_fail;
 	buffer_put_cstring(&buffer, "OK");
 	ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 	buffer_free(&buffer);
 	pthread_exit(NULL);

  auth_fail:
 	buffer_put_cstring(&buffer,
 	    pam_strerror(sshpam_handle, sshpam_err));
 	ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 	buffer_free(&buffer);
 	pthread_exit(NULL);

 	return (NULL); /* Avoid warning for non-pthread case */
 }

 void
 sshpam_thread_cleanup(void)
 {
 	struct pam_ctxt *ctxt = cleanup_ctxt;

 	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, const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
 	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 = sshpam_new_authtok_reqd = 0;
 	pam_end(sshpam_handle, sshpam_err);
 	sshpam_handle = NULL;
 }

 static int
 sshpam_init(const char *user)
 {
 	extern u_int utmp_len;
 	extern char *__progname;
 	const char *pam_rhost, *pam_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, (const 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);
 	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];

 	/* Refuse to start if we don't have PAM enabled */
 	if (!options.use_pam)
 		return NULL;

 	/* Initialize PAM */
 	if (sshpam_init(authctxt->user) == -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;

 	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) + 1;
 			**prompts = xrealloc(**prompts, len);
 			plen += snprintf(**prompts + plen, len, "%s", msg);
 			xfree(msg);
 			break;
 		case PAM_SUCCESS:
 		case PAM_AUTH_ERR:
 			if (**prompts != NULL) {
 				/* drain any accumulated messages */
 #if 0 /* XXX - not compatible with privsep */
 				packet_start(SSH2_MSG_USERAUTH_BANNER);
 				packet_put_cstring(**prompts);
 				packet_put_cstring("");
 				packet_send();
 				packet_write_wait();
 #endif
 				xfree(**prompts);
 				**prompts = NULL;
 			}
 			if (type == PAM_SUCCESS) {
 				*num = 0;
 				**echo_on = 0;
 				ctxt->pam_done = 1;
 				xfree(msg);
 				return (0);
 			}
 			error("PAM: %s", msg);
 			/* 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", __func__);
 	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);
 	ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
 	buffer_free(&buffer);
 	return (1);
 }

 static void
 sshpam_free_ctx(void *ctxtp)
 {
 	struct pam_ctxt *ctxt = ctxtp;

 	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(const char *user)
 {
 	if (!options.use_pam)
 		fatal("PAM: initialisation requested when UsePAM=no");

 	if (sshpam_init(user) == -1)
 		fatal("PAM: initialisation failed");
 }

 void
 finish_pam(void)
 {
 	sshpam_cleanup();
 }

 u_int
 do_pam_account(void)
 {
 	sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 	debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);

 	if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 		return (0);

 	if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 		sshpam_new_authtok_reqd = 1;

 		/* Prevent forwardings until password changed */
 		no_port_forwarding_flag |= 2;
 		no_agent_forwarding_flag |= 2;
 		no_x11_forwarding_flag |= 2;
 	}

 	return (1);
 }

 void
 do_pam_session(void)
 {
 	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));
 	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;
 }

 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));
 }

 int
 is_pam_password_change_required(void)
 {
 	return (sshpam_new_authtok_reqd);
 }

 static int
 pam_chauthtok_conv(int n, const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
 	char input[PAM_MAX_MSG_SIZE];
 	struct pam_response *reply;
 	int i;

 	*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:
 			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:
 			fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 			fgets(input, sizeof input, stdin);
 			reply[i].resp = xstrdup(input);
 			reply[i].resp_retcode = PAM_SUCCESS;
 			break;
 		case PAM_ERROR_MSG:
 		case PAM_TEXT_INFO:
 			fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 			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);
 }

 /*
  * XXX this should be done in the authentication phase, but ssh1 doesn't
  * support that
  */
 void
 do_pam_chauthtok(void)
 {
 	struct pam_conv pam_conv;

 	pam_conv.conv = pam_chauthtok_conv;
 	pam_conv.appdata_ptr = NULL;

 	if (use_privsep)
 		fatal("Password expired (unable to change with privsep)");
 	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 	    (const void *)&pam_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));
 }

 /*
  * 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);
 }

 void
 print_pam_messages(void)
 {
 	/* XXX */
 }

 char **
 fetch_pam_environment(void)
 {
 #ifdef HAVE_PAM_GETENVLIST
 	debug("PAM: retrieving environment");
 	return (pam_getenvlist(sshpam_handle));
 #else
 	return (NULL);
 #endif
 }

 void
 free_pam_environment(char **env)
 {
 	char **envp;

 	if (env == NULL)
 		return;

 	for (envp = env; *envp; envp++)
 		xfree(*envp);
 	xfree(env);
 }

 #endif /* USE_PAM */
	/*-
	* Copyright (c) 2002 Networks Associates Technology, Inc.
	* All rights reserved.
	*
	* This software was developed for the FreeBSD Project by ThinkSec AS and
	* NAI Labs, the Security Research Division of Network Associates, Inc.
	* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
	* DARPA CHATS research program.
	*
	* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
	*/

	/* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
	#include "includes.h"
	RCSID("$Id: auth-pam.c,v 1.76 2003/10/09 04:20:15 dtucker Exp $");

	#ifdef USE_PAM
	#include <security/pam_appl.h>

	#include "auth.h"
	#include "auth-pam.h"
	#include "buffer.h"
	#include "bufaux.h"
	#include "canohost.h"
	#include "log.h"
	#include "monitor_wrap.h"
	#include "msg.h"
	#include "packet.h"
	#include "readpass.h"
	#include "servconf.h"
	#include "ssh2.h"
	#include "xmalloc.h"
	#include "auth-options.h"

	extern ServerOptions options;

	#define __unused

	#ifdef USE_POSIX_THREADS
	#include <pthread.h>
	/*
	* Avoid namespace clash when not using pthreads for systems with
	* pthreads, which unconditionally define pthread_t via sys/types.h
	* (e.g. Linux)
	*/
	typedef pthread_t sp_pthread_t;
	#else
	/*
	* Simulate threads with processes.
	*/
	typedef pid_t sp_pthread_t;

	static void
	pthread_exit(void *value __unused)
	{
	_exit(0);
	}

	static int
	pthread_create(sp_pthread_t thread, const void attr __unused,
	void (thread_start)(void ), void arg)
	{
	pid_t pid;

	switch ((pid = fork())) {
	case -1:
	error("fork(): %s", strerror(errno));
	return (-1);
	case 0:
	thread_start(arg);
	_exit(1);
	default:
	*thread = pid;
	return (0);
	}
	}

	static int
	pthread_cancel(sp_pthread_t thread)
	{
	return (kill(thread, SIGTERM));
	}

	static int
	pthread_join(sp_pthread_t thread, void **value __unused)
	{
	int status;

	waitpid(thread, &status, 0);
	return (status);
	}
	#endif


	static pam_handle_t *sshpam_handle = NULL;
	static int sshpam_err = 0;
	static int sshpam_authenticated = 0;
	static int sshpam_new_authtok_reqd = 0;
	static int sshpam_session_open = 0;
	static int sshpam_cred_established = 0;

	struct pam_ctxt {
	sp_pthread_t pam_thread;
	int pam_psock;
	int pam_csock;
	int pam_done;
	};

	static void sshpam_free_ctx(void *);
	static struct pam_ctxt *cleanup_ctxt;

	/*
	* Conversation function for authentication thread.
	*/
	static int
	sshpam_thread_conv(int n, const struct pam_message **msg,
	struct pam_response *resp, void data)
	{
	Buffer buffer;
	struct pam_ctxt *ctxt;
	struct pam_response *reply;
	int i;

	*resp = NULL;

	ctxt = data;
	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));

	buffer_init(&buffer);
	for (i = 0; i < n; ++i) {
	switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
	case PAM_PROMPT_ECHO_OFF:
	buffer_put_cstring(&buffer,
	PAM_MSG_MEMBER(msg, i, msg));
	ssh_msg_send(ctxt->pam_csock,
	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	ssh_msg_recv(ctxt->pam_csock, &buffer);
	if (buffer_get_char(&buffer) != PAM_AUTHTOK)
	goto fail;
	reply[i].resp = buffer_get_string(&buffer, NULL);
	break;
	case PAM_PROMPT_ECHO_ON:
	buffer_put_cstring(&buffer,
	PAM_MSG_MEMBER(msg, i, msg));
	ssh_msg_send(ctxt->pam_csock,
	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	ssh_msg_recv(ctxt->pam_csock, &buffer);
	if (buffer_get_char(&buffer) != PAM_AUTHTOK)
	goto fail;
	reply[i].resp = buffer_get_string(&buffer, NULL);
	break;
	case PAM_ERROR_MSG:
	buffer_put_cstring(&buffer,
	PAM_MSG_MEMBER(msg, i, msg));
	ssh_msg_send(ctxt->pam_csock,
	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	break;
	case PAM_TEXT_INFO:
	buffer_put_cstring(&buffer,
	PAM_MSG_MEMBER(msg, i, msg));
	ssh_msg_send(ctxt->pam_csock,
	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	break;
	default:
	goto fail;
	}
	buffer_clear(&buffer);
	}
	buffer_free(&buffer);
	*resp = reply;
	return (PAM_SUCCESS);

	fail:
	for(i = 0; i < n; i++) {
	if (reply[i].resp != NULL)
	xfree(reply[i].resp);
	}
	xfree(reply);
	buffer_free(&buffer);
	return (PAM_CONV_ERR);
	}

	/*
	* Authentication thread.
	*/
	static void *
	sshpam_thread(void *ctxtp)
	{
	struct pam_ctxt *ctxt = ctxtp;
	Buffer buffer;
	struct pam_conv sshpam_conv;
	#ifndef USE_POSIX_THREADS
	const char *pam_user;

	pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
	setproctitle("%s [pam]", pam_user);
	#endif

	sshpam_conv.conv = sshpam_thread_conv;
	sshpam_conv.appdata_ptr = ctxt;

	buffer_init(&buffer);
	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	(const void *)&sshpam_conv);
	if (sshpam_err != PAM_SUCCESS)
	goto auth_fail;
	sshpam_err = pam_authenticate(sshpam_handle, 0);
	if (sshpam_err != PAM_SUCCESS)
	goto auth_fail;
	buffer_put_cstring(&buffer, "OK");
	ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
	buffer_free(&buffer);
	pthread_exit(NULL);

	auth_fail:
	buffer_put_cstring(&buffer,
	pam_strerror(sshpam_handle, sshpam_err));
	ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
	buffer_free(&buffer);
	pthread_exit(NULL);

	return (NULL); /* Avoid warning for non-pthread case */
	}

	void
	sshpam_thread_cleanup(void)
	{
	struct pam_ctxt *ctxt = cleanup_ctxt;

	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, const struct pam_message **msg,
	struct pam_response *resp, void data)
	{
	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 = sshpam_new_authtok_reqd = 0;
	pam_end(sshpam_handle, sshpam_err);
	sshpam_handle = NULL;
	}

	static int
	sshpam_init(const char *user)
	{
	extern u_int utmp_len;
	extern char *__progname;
	const char pam_rhost, pam_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, (const 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);
	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];

	/* Refuse to start if we don't have PAM enabled */
	if (!options.use_pam)
	return NULL;

	/* Initialize PAM */
	if (sshpam_init(authctxt->user) == -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;

	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) + 1;
	prompts = xrealloc(prompts, len);
	plen += snprintf(**prompts + plen, len, "%s", msg);
	xfree(msg);
	break;
	case PAM_SUCCESS:
	case PAM_AUTH_ERR:
	if (**prompts != NULL) {
	/* drain any accumulated messages */
	#if 0 /* XXX - not compatible with privsep */
	packet_start(SSH2_MSG_USERAUTH_BANNER);
	packet_put_cstring(**prompts);
	packet_put_cstring("");
	packet_send();
	packet_write_wait();
	#endif
	xfree(**prompts);
	**prompts = NULL;
	}
	if (type == PAM_SUCCESS) {
	*num = 0;
	**echo_on = 0;
	ctxt->pam_done = 1;
	xfree(msg);
	return (0);
	}
	error("PAM: %s", msg);
	/* 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", __func__);
	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);
	ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
	buffer_free(&buffer);
	return (1);
	}

	static void
	sshpam_free_ctx(void *ctxtp)
	{
	struct pam_ctxt *ctxt = ctxtp;

	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(const char *user)
	{
	if (!options.use_pam)
	fatal("PAM: initialisation requested when UsePAM=no");

	if (sshpam_init(user) == -1)
	fatal("PAM: initialisation failed");
	}

	void
	finish_pam(void)
	{
	sshpam_cleanup();
	}

	u_int
	do_pam_account(void)
	{
	sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
	debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);

	if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
	return (0);

	if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
	sshpam_new_authtok_reqd = 1;

	/* Prevent forwardings until password changed */
	no_port_forwarding_flag \|= 2;
	no_agent_forwarding_flag \|= 2;
	no_x11_forwarding_flag \|= 2;
	}

	return (1);
	}

	void
	do_pam_session(void)
	{
	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));
	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;
	}

	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));
	}

	int
	is_pam_password_change_required(void)
	{
	return (sshpam_new_authtok_reqd);
	}

	static int
	pam_chauthtok_conv(int n, const struct pam_message **msg,
	struct pam_response *resp, void data)
	{
	char input[PAM_MAX_MSG_SIZE];
	struct pam_response *reply;
	int i;

	*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:
	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:
	fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
	fgets(input, sizeof input, stdin);
	reply[i].resp = xstrdup(input);
	reply[i].resp_retcode = PAM_SUCCESS;
	break;
	case PAM_ERROR_MSG:
	case PAM_TEXT_INFO:
	fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
	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);
	}

	/*
	* XXX this should be done in the authentication phase, but ssh1 doesn't
	* support that
	*/
	void
	do_pam_chauthtok(void)
	{
	struct pam_conv pam_conv;

	pam_conv.conv = pam_chauthtok_conv;
	pam_conv.appdata_ptr = NULL;

	if (use_privsep)
	fatal("Password expired (unable to change with privsep)");
	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	(const void *)&pam_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));
	}

	/*
	* 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);
	}

	void
	print_pam_messages(void)
	{
	/* XXX */
	}

	char **
	fetch_pam_environment(void)
	{
	#ifdef HAVE_PAM_GETENVLIST
	debug("PAM: retrieving environment");
	return (pam_getenvlist(sshpam_handle));
	#else
	return (NULL);
	#endif
	}

	void
	free_pam_environment(char **env)
	{
	char **envp;

	if (env == NULL)
	return;

	for (envp = env; *envp; envp++)
	xfree(*envp);
	xfree(env);
	}

	#endif /* USE_PAM */