[openssh.git] / auth-pam.c

/*-
 * 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.
 */

#include "includes.h"
RCSID("$FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des 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"

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;
static int sshpam_err;
static int sshpam_authenticated;
static int sshpam_new_authtok_reqd;
static int sshpam_session_open;
static int sshpam_cred_established;

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

static void sshpam_free_ctx(void *);

/*
 * 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;
	int i;

	ctxt = data;
	if (n <= 0 || n > PAM_MAX_NUM_MSG)
		return (PAM_CONV_ERR);
	*resp = xmalloc(n * sizeof **resp);
	buffer_init(&buffer);
	for (i = 0; i < n; ++i) {
		resp[i]->resp_retcode = 0;
		resp[i]->resp = NULL;
		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;
			resp[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;
			resp[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);
	return (PAM_SUCCESS);
 fail:
	while (i)
		xfree(resp[--i]);
	xfree(*resp);
	*resp = NULL;
	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 = { sshpam_thread_conv, ctxt };
#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

	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;
	sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
	if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
		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 */
}

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

	pthread_cancel(ctxt->pam_thread);
	pthread_join(ctxt->pam_thread, NULL);
	close(ctxt->pam_psock);
	close(ctxt->pam_csock);
}

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 };

static void
sshpam_cleanup(void *arg)
{
	(void)arg;
	debug("PAM: cleanup");
	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;
	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);
		fatal_remove_cleanup(sshpam_cleanup, NULL);
		pam_end(sshpam_handle, sshpam_err);
		sshpam_handle = NULL;
	}
	debug("PAM: initializing for \"%s\"", user);
	sshpam_err = pam_start("sshd", user, &null_conv, &sshpam_handle);
	if (sshpam_err != PAM_SUCCESS)
		return (-1);
	pam_rhost = get_remote_name_or_ip(utmp_len,
	    options.verify_reverse_mapping);
	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);
	}
	fatal_add_cleanup(sshpam_cleanup, NULL);
	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);
	ctxt->pam_done = 0;

	/* 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);
	}
	fatal_add_cleanup(sshpam_thread_cleanup, 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;

	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;
			**prompts = xrealloc(**prompts, plen + strlen(msg) + 1);
			plen += sprintf(**prompts + plen, "%s", msg);
			**echo_on = (type == PAM_PROMPT_ECHO_ON);
			xfree(msg);
			return (0);
		case PAM_ERROR_MSG:
		case PAM_TEXT_INFO:
			/* accumulate messages */
			**prompts = xrealloc(**prompts, plen + strlen(msg) + 1);
			plen += sprintf(**prompts + plen, "%s", msg);
			xfree(msg);
			break;
		case PAM_NEW_AUTHTOK_REQD:
			sshpam_new_authtok_reqd = 1;
			/* FALLTHROUGH */
		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);
		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;

	fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
	sshpam_thread_cleanup(ctxtp);
	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)
{
	fatal_remove_cleanup(sshpam_cleanup, NULL);
	sshpam_cleanup(NULL);
}

int
do_pam_account(const char *user, const char *ruser)
{
	/* XXX */
	return (1);
}

void
do_pam_session(const char *user, const char *tty)
{
	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));
	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));
	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_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];
	int i;

	if (n <= 0 || n > PAM_MAX_NUM_MSG)
		return (PAM_CONV_ERR);
	*resp = xmalloc(n * sizeof **resp);
	for (i = 0; i < n; ++i) {
		switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
		case PAM_PROMPT_ECHO_OFF:
			resp[i]->resp =
			    read_passphrase(PAM_MSG_MEMBER(msg, i, msg), 
			    RP_ALLOW_STDIN);
			resp[i]->resp_retcode = PAM_SUCCESS;
			break;
		case PAM_PROMPT_ECHO_ON:
			fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
			fgets(input, sizeof input, stdin);
			resp[i]->resp = xstrdup(input);
			resp[i]->resp_retcode = PAM_SUCCESS;
			break;
		case PAM_ERROR_MSG:
		case PAM_TEXT_INFO:
			fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
			resp[i]->resp_retcode = PAM_SUCCESS;
			break;
		default:
			goto fail;
		}
	}
	return (PAM_SUCCESS);
 fail:
	while (i)
		xfree(resp[--i]);
	xfree(*resp);
	*resp = NULL;
	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_chauthtok_conv, NULL };

	if (use_privsep)
		fatal("PAM: chauthtok not supprted 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));
}

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 */
Commit	Line	Data
05114c74	1	/*-
	2	* Copyright (c) 2002 Networks Associates Technology, Inc.
	3	* All rights reserved.
	4	*
	5	* This software was developed for the FreeBSD Project by ThinkSec AS and
	6	* NAI Labs, the Security Research Division of Network Associates, Inc.
	7	* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
	8	* DARPA CHATS research program.
09564242	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
09564242	18	*
05114c74	19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	20	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	21	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	22	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	23	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	24	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	25	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	26	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	27	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	28	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	29	* SUCH DAMAGE.
a5c9cd31	30	*/
	31
	32	#include "includes.h"
05114c74	33	RCSID("$FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $");
a5c9cd31	34
a5c9cd31	35	#ifdef USE_PAM
05114c74	36	#include <security/pam_appl.h>
05114c74	37
fde58bd4	38	#include "auth.h"
5c377b3b	39	#include "auth-pam.h"
05114c74	40	#include "buffer.h"
05114c74	41	#include "bufaux.h"
42f11eb2	42	#include "canohost.h"
05114c74	43	#include "log.h"
	44	#include "monitor_wrap.h"
	45	#include "msg.h"
	46	#include "packet.h"
42f11eb2	47	#include "readpass.h"
05114c74	48	#include "servconf.h"
	49	#include "ssh2.h"
	50	#include "xmalloc.h"
a5c9cd31	51
7fceb20d	52	extern ServerOptions options;
7fceb20d	53
05114c74	54	#define __unused
277f55cf	55
05114c74	56	#ifdef USE_POSIX_THREADS
	57	#include <pthread.h>
	58	/*
	59	* Avoid namespace clash when not using pthreads for systems with
	60	* pthreads, which unconditionally define pthread_t via sys/types.h
	61	* (e.g. Linux)
	62	*/
	63	typedef pthread_t sp_pthread_t;
	64	#else
	65	/*
	66	* Simulate threads with processes.
	67	*/
	68	typedef pid_t sp_pthread_t;
a5c9cd31	69
05114c74	70	static void
	71	pthread_exit(void *value __unused)
	72	{
	73	_exit(0);
	74	}
5daf7064	75
05114c74	76	static int
	77	pthread_create(sp_pthread_t thread, const void attr __unused,
	78	void (thread_start)(void ), void arg)
	79	{
	80	pid_t pid;
	81
	82	switch ((pid = fork())) {
	83	case -1:
	84	error("fork(): %s", strerror(errno));
	85	return (-1);
	86	case 0:
	87	thread_start(arg);
	88	_exit(1);
	89	default:
	90	*thread = pid;
	91	return (0);
	92	}
	93	}
a5c9cd31	94
05114c74	95	static int
05114c74	96	pthread_cancel(sp_pthread_t thread)
8c9fe09e	97	{
05114c74	98	return (kill(thread, SIGTERM));
8c9fe09e	99	}
8c9fe09e	100
05114c74	101	static int
05114c74	102	pthread_join(sp_pthread_t thread, void **value __unused)
8c9fe09e	103	{
05114c74	104	int status;
	105
	106	waitpid(thread, &status, 0);
	107	return (status);
8c9fe09e	108	}
05114c74	109	#endif
	110
	111
	112	static pam_handle_t *sshpam_handle;
	113	static int sshpam_err;
	114	static int sshpam_authenticated;
	115	static int sshpam_new_authtok_reqd;
	116	static int sshpam_session_open;
	117	static int sshpam_cred_established;
	118
	119	struct pam_ctxt {
	120	sp_pthread_t pam_thread;
	121	int pam_psock;
	122	int pam_csock;
	123	int pam_done;
	124	};
	125
	126	static void sshpam_free_ctx(void *);
ad55cd03	127
ad55cd03	128	/*
05114c74	129	* Conversation function for authentication thread.
ad55cd03	130	*/
05114c74	131	static int
	132	sshpam_thread_conv(int n,
	133	const struct pam_message **msg,
	134	struct pam_response **resp,
	135	void *data)
a5c9cd31	136	{
05114c74	137	Buffer buffer;
	138	struct pam_ctxt *ctxt;
	139	int i;
	140
	141	ctxt = data;
	142	if (n <= 0 \|\| n > PAM_MAX_NUM_MSG)
	143	return (PAM_CONV_ERR);
	144	resp = xmalloc(n sizeof **resp);
	145	buffer_init(&buffer);
	146	for (i = 0; i < n; ++i) {
	147	resp[i]->resp_retcode = 0;
	148	resp[i]->resp = NULL;
	149	switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
	150	case PAM_PROMPT_ECHO_OFF:
	151	buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
	152	ssh_msg_send(ctxt->pam_csock,
	153	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	154	ssh_msg_recv(ctxt->pam_csock, &buffer);
	155	if (buffer_get_char(&buffer) != PAM_AUTHTOK)
	156	goto fail;
	157	resp[i]->resp = buffer_get_string(&buffer, NULL);
	158	break;
	159	case PAM_PROMPT_ECHO_ON:
	160	buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
	161	ssh_msg_send(ctxt->pam_csock,
	162	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	163	ssh_msg_recv(ctxt->pam_csock, &buffer);
	164	if (buffer_get_char(&buffer) != PAM_AUTHTOK)
	165	goto fail;
	166	resp[i]->resp = buffer_get_string(&buffer, NULL);
	167	break;
	168	case PAM_ERROR_MSG:
	169	buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
	170	ssh_msg_send(ctxt->pam_csock,
	171	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	172	break;
	173	case PAM_TEXT_INFO:
	174	buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
	175	ssh_msg_send(ctxt->pam_csock,
	176	PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
	177	break;
	178	default:
	179	goto fail;
a5c9cd31	180	}
05114c74	181	buffer_clear(&buffer);
a5c9cd31	182	}
05114c74	183	buffer_free(&buffer);
	184	return (PAM_SUCCESS);
	185	fail:
	186	while (i)
	187	xfree(resp[--i]);
	188	xfree(*resp);
	189	*resp = NULL;
	190	buffer_free(&buffer);
	191	return (PAM_CONV_ERR);
	192	}
a5c9cd31	193
05114c74	194	/*
	195	* Authentication thread.
	196	*/
	197	static void *
	198	sshpam_thread(void *ctxtp)
	199	{
	200	struct pam_ctxt *ctxt = ctxtp;
	201	Buffer buffer;
	202	struct pam_conv sshpam_conv = { sshpam_thread_conv, ctxt };
	203	#ifndef USE_POSIX_THREADS
	204	const char *pam_user;
	205
	206	pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
	207	setproctitle("%s [pam]", pam_user);
	208	#endif
a5c9cd31	209
05114c74	210	buffer_init(&buffer);
	211	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	212	(const void *)&sshpam_conv);
	213	if (sshpam_err != PAM_SUCCESS)
	214	goto auth_fail;
	215	sshpam_err = pam_authenticate(sshpam_handle, 0);
	216	if (sshpam_err != PAM_SUCCESS)
	217	goto auth_fail;
	218	sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
	219	if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
	220	goto auth_fail;
	221	buffer_put_cstring(&buffer, "OK");
	222	ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
	223	buffer_free(&buffer);
	224	pthread_exit(NULL);
	225
	226	auth_fail:
	227	buffer_put_cstring(&buffer,
	228	pam_strerror(sshpam_handle, sshpam_err));
	229	ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
	230	buffer_free(&buffer);
	231	pthread_exit(NULL);
	232
	233	return (NULL); /* Avoid warning for non-pthread case */
a5c9cd31	234	}
a5c9cd31	235
05114c74	236	static void
05114c74	237	sshpam_thread_cleanup(void *ctxtp)
a5c9cd31	238	{
05114c74	239	struct pam_ctxt *ctxt = ctxtp;
a5c9cd31	240
05114c74	241	pthread_cancel(ctxt->pam_thread);
	242	pthread_join(ctxt->pam_thread, NULL);
	243	close(ctxt->pam_psock);
	244	close(ctxt->pam_csock);
	245	}
a5c9cd31	246
05114c74	247	static int
	248	sshpam_null_conv(int n,
	249	const struct pam_message **msg,
	250	struct pam_response **resp,
	251	void *data)
	252	{
	253
	254	return (PAM_CONV_ERR);
	255	}
a5c9cd31	256
05114c74	257	static struct pam_conv null_conv = { sshpam_null_conv, NULL };
	258
	259	static void
	260	sshpam_cleanup(void *arg)
	261	{
	262	(void)arg;
	263	debug("PAM: cleanup");
	264	pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
	265	if (sshpam_cred_established) {
	266	pam_setcred(sshpam_handle, PAM_DELETE_CRED);
	267	sshpam_cred_established = 0;
	268	}
	269	if (sshpam_session_open) {
	270	pam_close_session(sshpam_handle, PAM_SILENT);
	271	sshpam_session_open = 0;
a5c9cd31	272	}
05114c74	273	sshpam_authenticated = sshpam_new_authtok_reqd = 0;
	274	pam_end(sshpam_handle, sshpam_err);
	275	sshpam_handle = NULL;
a5c9cd31	276	}
a5c9cd31	277
05114c74	278	static int
05114c74	279	sshpam_init(const char *user)
a5c9cd31	280	{
05114c74	281	extern u_int utmp_len;
	282	const char pam_rhost, pam_user;
	283
	284	if (sshpam_handle != NULL) {
	285	/* We already have a PAM context; check if the user matches */
	286	sshpam_err = pam_get_item(sshpam_handle,
	287	PAM_USER, (const void **)&pam_user);
	288	if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
	289	return (0);
	290	fatal_remove_cleanup(sshpam_cleanup, NULL);
	291	pam_end(sshpam_handle, sshpam_err);
	292	sshpam_handle = NULL;
	293	}
	294	debug("PAM: initializing for \"%s\"", user);
	295	sshpam_err = pam_start("sshd", user, &null_conv, &sshpam_handle);
	296	if (sshpam_err != PAM_SUCCESS)
	297	return (-1);
	298	pam_rhost = get_remote_name_or_ip(utmp_len,
	299	options.verify_reverse_mapping);
	300	debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
	301	sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
	302	if (sshpam_err != PAM_SUCCESS) {
	303	pam_end(sshpam_handle, sshpam_err);
	304	sshpam_handle = NULL;
	305	return (-1);
a5c9cd31	306	}
05114c74	307	fatal_add_cleanup(sshpam_cleanup, NULL);
05114c74	308	return (0);
a5c9cd31	309	}
a5c9cd31	310
05114c74	311	static void *
05114c74	312	sshpam_init_ctx(Authctxt *authctxt)
a5c9cd31	313	{
05114c74	314	struct pam_ctxt *ctxt;
05114c74	315	int socks[2];
2b87da3b	316
7fceb20d	317	/* Refuse to start if we don't have PAM enabled */
	318	if (!options.use_pam)
	319	return NULL;
	320
05114c74	321	/* Initialize PAM */
	322	if (sshpam_init(authctxt->user) == -1) {
	323	error("PAM: initialization failed");
	324	return (NULL);
	325	}
5c377b3b	326
05114c74	327	ctxt = xmalloc(sizeof *ctxt);
	328	ctxt->pam_done = 0;
	329
	330	/* Start the authentication thread */
	331	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
	332	error("PAM: failed create sockets: %s", strerror(errno));
	333	xfree(ctxt);
	334	return (NULL);
	335	}
	336	ctxt->pam_psock = socks[0];
	337	ctxt->pam_csock = socks[1];
	338	if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
	339	error("PAM: failed to start authentication thread: %s",
	340	strerror(errno));
	341	close(socks[0]);
	342	close(socks[1]);
	343	xfree(ctxt);
	344	return (NULL);
a5c9cd31	345	}
05114c74	346	fatal_add_cleanup(sshpam_thread_cleanup, ctxt);
	347	return (ctxt);
	348	}
a5c9cd31	349
05114c74	350	static int
	351	sshpam_query(void ctx, char name, char *info,
	352	u_int num, char prompts, u_int echo_on)
	353	{
	354	Buffer buffer;
	355	struct pam_ctxt *ctxt = ctx;
	356	size_t plen;
	357	u_char type;
	358	char *msg;
	359
	360	buffer_init(&buffer);
	361	*name = xstrdup("");
	362	*info = xstrdup("");
	363	prompts = xmalloc(sizeof(char ));
	364	**prompts = NULL;
	365	plen = 0;
	366	*echo_on = xmalloc(sizeof(u_int));
	367	while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
	368	type = buffer_get_char(&buffer);
	369	msg = buffer_get_string(&buffer, NULL);
	370	switch (type) {
	371	case PAM_PROMPT_ECHO_ON:
	372	case PAM_PROMPT_ECHO_OFF:
	373	*num = 1;
	374	prompts = xrealloc(prompts, plen + strlen(msg) + 1);
	375	plen += sprintf(**prompts + plen, "%s", msg);
	376	**echo_on = (type == PAM_PROMPT_ECHO_ON);
	377	xfree(msg);
	378	return (0);
	379	case PAM_ERROR_MSG:
	380	case PAM_TEXT_INFO:
	381	/* accumulate messages */
	382	prompts = xrealloc(prompts, plen + strlen(msg) + 1);
	383	plen += sprintf(**prompts + plen, "%s", msg);
	384	xfree(msg);
5daf7064	385	break;
5daf7064	386	case PAM_NEW_AUTHTOK_REQD:
05114c74	387	sshpam_new_authtok_reqd = 1;
	388	/* FALLTHROUGH */
	389	case PAM_SUCCESS:
	390	case PAM_AUTH_ERR:
	391	if (**prompts != NULL) {
	392	/* drain any accumulated messages */
	393	#if 0 /* XXX - not compatible with privsep */
	394	packet_start(SSH2_MSG_USERAUTH_BANNER);
	395	packet_put_cstring(**prompts);
	396	packet_put_cstring("");
	397	packet_send();
	398	packet_write_wait();
e108cd93	399	#endif
05114c74	400	xfree(**prompts);
	401	**prompts = NULL;
	402	}
	403	if (type == PAM_SUCCESS) {
	404	*num = 0;
	405	**echo_on = 0;
	406	ctxt->pam_done = 1;
	407	xfree(msg);
	408	return (0);
	409	}
	410	error("PAM: %s", msg);
5daf7064	411	default:
05114c74	412	*num = 0;
	413	**echo_on = 0;
	414	xfree(msg);
	415	ctxt->pam_done = -1;
	416	return (-1);
	417	}
a5c9cd31	418	}
05114c74	419	return (-1);
a5c9cd31	420	}
a5c9cd31	421
05114c74	422	/* XXX - see also comment in auth-chall.c:verify_response */
	423	static int
	424	sshpam_respond(void ctx, u_int num, char *resp)
a5c9cd31	425	{
05114c74	426	Buffer buffer;
	427	struct pam_ctxt *ctxt = ctx;
	428
	429	debug2("PAM: %s", __func__);
	430	switch (ctxt->pam_done) {
	431	case 1:
	432	sshpam_authenticated = 1;
	433	return (0);
	434	case 0:
	435	break;
	436	default:
	437	return (-1);
a5c9cd31	438	}
05114c74	439	if (num != 1) {
	440	error("PAM: expected one response, got %u", num);
	441	return (-1);
	442	}
	443	buffer_init(&buffer);
	444	buffer_put_cstring(&buffer, *resp);
	445	ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
	446	buffer_free(&buffer);
	447	return (1);
a5c9cd31	448	}
a5c9cd31	449
05114c74	450	static void
05114c74	451	sshpam_free_ctx(void *ctxtp)
a5c9cd31	452	{
05114c74	453	struct pam_ctxt *ctxt = ctxtp;
39ce53de	454
05114c74	455	fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
	456	sshpam_thread_cleanup(ctxtp);
	457	xfree(ctxt);
	458	/*
	459	* We don't call sshpam_cleanup() here because we may need the PAM
	460	* handle at a later stage, e.g. when setting up a session. It's
	461	* still on the cleanup list, so pam_end() will be called before
	462	* the server process terminates.
	463	*/
ad55cd03	464	}
ad55cd03	465
05114c74	466	KbdintDevice sshpam_device = {
	467	"pam",
	468	sshpam_init_ctx,
	469	sshpam_query,
	470	sshpam_respond,
	471	sshpam_free_ctx
	472	};
	473
	474	KbdintDevice mm_sshpam_device = {
	475	"pam",
	476	mm_sshpam_init_ctx,
	477	mm_sshpam_query,
	478	mm_sshpam_respond,
	479	mm_sshpam_free_ctx
	480	};
2919e060	481
2b87da3b	482	/*
05114c74	483	* This replaces auth-pam.c
ad55cd03	484	*/
05114c74	485	void
05114c74	486	start_pam(const char *user)
ad55cd03	487	{
817e6d38	488	if (!options.use_pam)
	489	fatal("PAM: initialisation requested when UsePAM=no");
	490
05114c74	491	if (sshpam_init(user) == -1)
05114c74	492	fatal("PAM: initialisation failed");
a5c9cd31	493	}
a5c9cd31	494
05114c74	495	void
05114c74	496	finish_pam(void)
a5c9cd31	497	{
05114c74	498	fatal_remove_cleanup(sshpam_cleanup, NULL);
05114c74	499	sshpam_cleanup(NULL);
a5c9cd31	500	}
a5c9cd31	501
05114c74	502	int
05114c74	503	do_pam_account(const char user, const char ruser)
a5c9cd31	504	{
05114c74	505	/* XXX */
	506	return (1);
	507	}
46c76c63	508
05114c74	509	void
	510	do_pam_session(const char user, const char tty)
	511	{
	512	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	513	(const void *)&null_conv);
	514	if (sshpam_err != PAM_SUCCESS)
	515	fatal("PAM: failed to set PAM_CONV: %s",
	516	pam_strerror(sshpam_handle, sshpam_err));
	517	debug("PAM: setting PAM_TTY to \"%s\"", tty);
	518	sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
	519	if (sshpam_err != PAM_SUCCESS)
	520	fatal("PAM: failed to set PAM_TTY: %s",
	521	pam_strerror(sshpam_handle, sshpam_err));
	522	sshpam_err = pam_open_session(sshpam_handle, 0);
	523	if (sshpam_err != PAM_SUCCESS)
	524	fatal("PAM: pam_open_session(): %s",
	525	pam_strerror(sshpam_handle, sshpam_err));
	526	sshpam_session_open = 1;
	527	}
cbd7492e	528
05114c74	529	void
	530	do_pam_setcred(int init)
	531	{
	532	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	533	(const void *)&null_conv);
	534	if (sshpam_err != PAM_SUCCESS)
	535	fatal("PAM: failed to set PAM_CONV: %s",
	536	pam_strerror(sshpam_handle, sshpam_err));
	537	if (init) {
	538	debug("PAM: establishing credentials");
	539	sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
	540	} else {
	541	debug("PAM: reinitializing credentials");
	542	sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
	543	}
	544	if (sshpam_err == PAM_SUCCESS) {
	545	sshpam_cred_established = 1;
	546	return;
	547	}
	548	if (sshpam_authenticated)
	549	fatal("PAM: pam_setcred(): %s",
	550	pam_strerror(sshpam_handle, sshpam_err));
	551	else
	552	debug("PAM: pam_setcred(): %s",
	553	pam_strerror(sshpam_handle, sshpam_err));
a5c9cd31	554	}
a5c9cd31	555
05114c74	556	int
05114c74	557	is_pam_password_change_required(void)
a5c9cd31	558	{
05114c74	559	return (sshpam_new_authtok_reqd);
a5c9cd31	560	}
a5c9cd31	561
05114c74	562	static int
	563	pam_chauthtok_conv(int n,
	564	const struct pam_message **msg,
	565	struct pam_response **resp,
	566	void *data)
ee48c949	567	{
05114c74	568	char input[PAM_MAX_MSG_SIZE];
ee48c949	569	int i;
ee48c949	570
05114c74	571	if (n <= 0 \|\| n > PAM_MAX_NUM_MSG)
	572	return (PAM_CONV_ERR);
	573	resp = xmalloc(n sizeof **resp);
	574	for (i = 0; i < n; ++i) {
	575	switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
	576	case PAM_PROMPT_ECHO_OFF:
	577	resp[i]->resp =
	578	read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
	579	RP_ALLOW_STDIN);
	580	resp[i]->resp_retcode = PAM_SUCCESS;
	581	break;
	582	case PAM_PROMPT_ECHO_ON:
	583	fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
	584	fgets(input, sizeof input, stdin);
	585	resp[i]->resp = xstrdup(input);
	586	resp[i]->resp_retcode = PAM_SUCCESS;
	587	break;
	588	case PAM_ERROR_MSG:
	589	case PAM_TEXT_INFO:
	590	fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
	591	resp[i]->resp_retcode = PAM_SUCCESS;
	592	break;
	593	default:
	594	goto fail;
	595	}
ee48c949	596	}
05114c74	597	return (PAM_SUCCESS);
	598	fail:
	599	while (i)
	600	xfree(resp[--i]);
	601	xfree(*resp);
	602	*resp = NULL;
	603	return (PAM_CONV_ERR);
ee48c949	604	}
ee48c949	605
05114c74	606	/*
	607	* XXX this should be done in the authentication phase, but ssh1 doesn't
	608	* support that
	609	*/
	610	void
	611	do_pam_chauthtok(void)
a5c9cd31	612	{
05114c74	613	struct pam_conv pam_conv = { pam_chauthtok_conv, NULL };
	614
	615	if (use_privsep)
	616	fatal("PAM: chauthtok not supprted with privsep");
	617	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	618	(const void *)&pam_conv);
	619	if (sshpam_err != PAM_SUCCESS)
	620	fatal("PAM: failed to set PAM_CONV: %s",
	621	pam_strerror(sshpam_handle, sshpam_err));
	622	debug("PAM: changing password");
	623	sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
	624	if (sshpam_err != PAM_SUCCESS)
	625	fatal("PAM: pam_chauthtok(): %s",
	626	pam_strerror(sshpam_handle, sshpam_err));
5daf7064	627	}
5daf7064	628
05114c74	629	void
05114c74	630	print_pam_messages(void)
5daf7064	631	{
05114c74	632	/* XXX */
05114c74	633	}
2b87da3b	634
05114c74	635	char **
	636	fetch_pam_environment(void)
	637	{
	638	#ifdef HAVE_PAM_GETENVLIST
	639	debug("PAM: retrieving environment");
	640	return (pam_getenvlist(sshpam_handle));
	641	#else
	642	return (NULL);
	643	#endif
	644	}
5c377b3b	645
05114c74	646	void
	647	free_pam_environment(char **env)
	648	{
	649	char **envp;
5daf7064	650
0eb6370a	651	if (env == NULL)
	652	return;
	653
05114c74	654	for (envp = env; *envp; envp++)
	655	xfree(*envp);
	656	xfree(env);
a5c9cd31	657	}
	658
	659	#endif /* USE_PAM */