[openssh.git] / auth-pam.c

/*
 * Copyright (c) 2000 Damien Miller.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#ifdef USE_PAM
#include "ssh.h"
#include "xmalloc.h"
#include "log.h"
#include "auth.h"
#include "auth-options.h"
#include "auth-pam.h"
#include "servconf.h"
#include "canohost.h"
#include "readpass.h"

extern char *__progname;

extern int use_privsep;

RCSID("$Id$");

#define NEW_AUTHTOK_MSG \
	"Warning: Your password has expired, please change it now."
#define NEW_AUTHTOK_MSG_PRIVSEP \
	"Your password has expired, the session cannot proceed."

static int do_pam_conversation(int num_msg, const struct pam_message **msg,
	struct pam_response **resp, void *appdata_ptr);

/* module-local variables */
static struct pam_conv conv = {
	(int (*)())do_pam_conversation,
	NULL
};
static char *__pam_msg = NULL;
static pam_handle_t *__pamh = NULL;
static const char *__pampasswd = NULL;

/* states for do_pam_conversation() */
enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
/* remember whether pam_acct_mgmt() returned PAM_NEW_AUTHTOK_REQD */
static int password_change_required = 0;
/* remember whether the last pam_authenticate() succeeded or not */
static int was_authenticated = 0;

/* Remember what has been initialised */
static int session_opened = 0;
static int creds_set = 0;

/* accessor which allows us to switch conversation structs according to
 * the authentication method being used */
void do_pam_set_conv(struct pam_conv *conv)
{
	pam_set_item(__pamh, PAM_CONV, conv);
}

/* start an authentication run */
int do_pam_authenticate(int flags)
{
	int retval = pam_authenticate(__pamh, flags);
	was_authenticated = (retval == PAM_SUCCESS);
	return retval;
}

/*
 * PAM conversation function.
 * There are two states this can run in.
 *
 * INITIAL_LOGIN mode simply feeds the password from the client into
 * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
 * messages with into __pam_msg.  This is used during initial
 * authentication to bypass the normal PAM password prompt.
 *
 * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase()
 * and outputs messages to stderr. This mode is used if pam_chauthtok()
 * is called to update expired passwords.
 */
static int do_pam_conversation(int num_msg, const struct pam_message **msg,
	struct pam_response **resp, void *appdata_ptr)
{
	struct pam_response *reply;
	int count;
	char buf[1024];

	/* PAM will free this later */
	reply = xmalloc(num_msg * sizeof(*reply));

	for (count = 0; count < num_msg; count++) {
		if (pamstate == INITIAL_LOGIN) {
			/*
			 * We can't use stdio yet, queue messages for 
			 * printing later
			 */
			switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
			case PAM_PROMPT_ECHO_ON:
				xfree(reply);
				return PAM_CONV_ERR;
			case PAM_PROMPT_ECHO_OFF:
				if (__pampasswd == NULL) {
					xfree(reply);
					return PAM_CONV_ERR;
				}
				reply[count].resp = xstrdup(__pampasswd);
				reply[count].resp_retcode = PAM_SUCCESS;
				break;
			case PAM_ERROR_MSG:
			case PAM_TEXT_INFO:
				if (PAM_MSG_MEMBER(msg, count, msg) != NULL) {
					message_cat(&__pam_msg, 
					    PAM_MSG_MEMBER(msg, count, msg));
				}
				reply[count].resp = xstrdup("");
				reply[count].resp_retcode = PAM_SUCCESS;
				break;
			default:
				xfree(reply);
				return PAM_CONV_ERR;
			}
		} else {
			/*
			 * stdio is connected, so interact directly
			 */
			switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
			case PAM_PROMPT_ECHO_ON:
				fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
				fgets(buf, sizeof(buf), stdin);
				reply[count].resp = xstrdup(buf);
				reply[count].resp_retcode = PAM_SUCCESS;
				break;
			case PAM_PROMPT_ECHO_OFF:
				reply[count].resp = 
				    read_passphrase(PAM_MSG_MEMBER(msg, count,
					msg), RP_ALLOW_STDIN);
				reply[count].resp_retcode = PAM_SUCCESS;
				break;
			case PAM_ERROR_MSG:
			case PAM_TEXT_INFO:
				if ((*msg)[count].msg != NULL)
					fprintf(stderr, "%s\n", 
					    PAM_MSG_MEMBER(msg, count, msg));
				reply[count].resp = xstrdup("");
				reply[count].resp_retcode = PAM_SUCCESS;
				break;
			default:
				xfree(reply);
				return PAM_CONV_ERR;
			}
		}
	}

	*resp = reply;

	return PAM_SUCCESS;
}

/* Called at exit to cleanly shutdown PAM */
void do_pam_cleanup_proc(void *context)
{
	int pam_retval = PAM_SUCCESS;

	if (__pamh && session_opened) {
		pam_retval = pam_close_session(__pamh, 0);
		if (pam_retval != PAM_SUCCESS)
			log("Cannot close PAM session[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
	}

	if (__pamh && creds_set) {
		pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED);
		if (pam_retval != PAM_SUCCESS)
			debug("Cannot delete credentials[%d]: %.200s", 
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
	}

	if (__pamh) {
		pam_retval = pam_end(__pamh, pam_retval);
		if (pam_retval != PAM_SUCCESS)
			log("Cannot release PAM authentication[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
	}
}

/* Attempt password authentation using PAM */
int auth_pam_password(Authctxt *authctxt, const char *password)
{
	extern ServerOptions options;
	int pam_retval;
	struct passwd *pw = authctxt->pw;

	do_pam_set_conv(&conv);

	/* deny if no user. */
	if (pw == NULL)
		return 0;
	if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD)
		return 0;
	if (*password == '\0' && options.permit_empty_passwd == 0)
		return 0;

	__pampasswd = password;

	pamstate = INITIAL_LOGIN;
	pam_retval = do_pam_authenticate(
	    options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0);
	if (pam_retval == PAM_SUCCESS) {
		debug("PAM Password authentication accepted for "
		    "user \"%.100s\"", pw->pw_name);
		return 1;
	} else {
		debug("PAM Password authentication for \"%.100s\" "
		    "failed[%d]: %s", pw->pw_name, pam_retval, 
		    PAM_STRERROR(__pamh, pam_retval));
		return 0;
	}
}

/* Do account management using PAM */
int do_pam_account(char *username, char *remote_user)
{
	int pam_retval;

	do_pam_set_conv(&conv);

	if (remote_user) {
		debug("PAM setting ruser to \"%.200s\"", remote_user);
		pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user);
		if (pam_retval != PAM_SUCCESS)
			fatal("PAM set ruser failed[%d]: %.200s", pam_retval, 
			    PAM_STRERROR(__pamh, pam_retval));
	}

	pam_retval = pam_acct_mgmt(__pamh, 0);
	debug2("pam_acct_mgmt() = %d", pam_retval);
	switch (pam_retval) {
		case PAM_SUCCESS:
			/* This is what we want */
			break;
#if 0
		case PAM_NEW_AUTHTOK_REQD:
			message_cat(&__pam_msg, use_privsep ?
			    NEW_AUTHTOK_MSG_PRIVSEP : NEW_AUTHTOK_MSG);
			/* flag that password change is necessary */
			password_change_required = 1;
			/* disallow other functionality for now */
			no_port_forwarding_flag |= 2;
			no_agent_forwarding_flag |= 2;
			no_x11_forwarding_flag |= 2;
			break;
#endif
		default:
			log("PAM rejected by account configuration[%d]: "
			    "%.200s", pam_retval, PAM_STRERROR(__pamh, 
			    pam_retval));
			return(0);
	}

	return(1);
}

/* Do PAM-specific session initialisation */
void do_pam_session(char *username, const char *ttyname)
{
	int pam_retval;

	do_pam_set_conv(&conv);

	if (ttyname != NULL) {
		debug("PAM setting tty to \"%.200s\"", ttyname);
		pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname);
		if (pam_retval != PAM_SUCCESS)
			fatal("PAM set tty failed[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
	}

	pam_retval = pam_open_session(__pamh, 0);
	if (pam_retval != PAM_SUCCESS)
		fatal("PAM session setup failed[%d]: %.200s",
		    pam_retval, PAM_STRERROR(__pamh, pam_retval));

	session_opened = 1;
}

/* Set PAM credentials */
void do_pam_setcred(int init)
{
	int pam_retval;

	if (__pamh == NULL)
		return;

	do_pam_set_conv(&conv);

	debug("PAM establishing creds");
	pam_retval = pam_setcred(__pamh, 
	    init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED);
	if (pam_retval != PAM_SUCCESS) {
		if (was_authenticated)
			fatal("PAM setcred failed[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
		else
			debug("PAM setcred failed[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
	} else
		creds_set = 1;
}

/* accessor function for file scope static variable */
int is_pam_password_change_required(void)
{
	return password_change_required;
}

/*
 * Have user change authentication token if pam_acct_mgmt() indicated
 * it was expired.  This needs to be called after an interactive
 * session is established and the user's pty is connected to
 * stdin/stdout/stderr.
 */
void do_pam_chauthtok(void)
{
	int pam_retval;

	do_pam_set_conv(&conv);

	if (password_change_required) {
		if (use_privsep)
			fatal("Password changing is currently unsupported"
			    " with privilege separation");
		pamstate = OTHER;
		pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
		if (pam_retval != PAM_SUCCESS)
			fatal("PAM pam_chauthtok failed[%d]: %.200s",
			    pam_retval, PAM_STRERROR(__pamh, pam_retval));
#if 0
		/* XXX: This would need to be done in the parent process,
		 * but there's currently no way to pass such request. */
		no_port_forwarding_flag &= ~2;
		no_agent_forwarding_flag &= ~2;
		no_x11_forwarding_flag &= ~2;
		if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
			channel_permit_all_opens();
#endif
	}
}

/* Cleanly shutdown PAM */
void finish_pam(void)
{
	do_pam_cleanup_proc(NULL);
	fatal_remove_cleanup(&do_pam_cleanup_proc, NULL);
}

/* Start PAM authentication for specified account */
void start_pam(const char *user)
{
	int pam_retval;
	extern ServerOptions options;
	extern u_int utmp_len;
	const char *rhost;

	debug("Starting up PAM with username \"%.200s\"", user);

	pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh);

	if (pam_retval != PAM_SUCCESS)
		fatal("PAM initialisation failed[%d]: %.200s",
		    pam_retval, PAM_STRERROR(__pamh, pam_retval));

	rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping);
	debug("PAM setting rhost to \"%.200s\"", rhost);

	pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost);
	if (pam_retval != PAM_SUCCESS)
		fatal("PAM set rhost failed[%d]: %.200s", pam_retval,
		    PAM_STRERROR(__pamh, pam_retval));
#ifdef PAM_TTY_KLUDGE
	/*
	 * Some PAM modules (e.g. pam_time) require a TTY to operate,
	 * and will fail in various stupid ways if they don't get one.
	 * sshd doesn't set the tty until too late in the auth process and may
	 * not even need one (for tty-less connections)
	 * Kludge: Set a fake PAM_TTY
	 */
	pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh");
	if (pam_retval != PAM_SUCCESS)
		fatal("PAM set tty failed[%d]: %.200s",
		    pam_retval, PAM_STRERROR(__pamh, pam_retval));
#endif /* PAM_TTY_KLUDGE */

	fatal_add_cleanup(&do_pam_cleanup_proc, NULL);
}

/* Return list of PAM enviornment strings */
char **fetch_pam_environment(void)
{
#ifdef HAVE_PAM_GETENVLIST
	return(pam_getenvlist(__pamh));
#else /* HAVE_PAM_GETENVLIST */
	return(NULL);
#endif /* HAVE_PAM_GETENVLIST */
}

/* Print any messages that have been generated during authentication */
/* or account checking to stderr */
void print_pam_messages(void)
{
	if (__pam_msg != NULL)
		fputs(__pam_msg, stderr);
}

/* Append a message to buffer */
void message_cat(char **p, const char *a)
{
	char *cp;
	size_t new_len;

	new_len = strlen(a);

	if (*p) {
		size_t len = strlen(*p);

		*p = xrealloc(*p, new_len + len + 2);
		cp = *p + len;
	} else
		*p = cp = xmalloc(new_len + 2);

	memcpy(cp, a, new_len);
	cp[new_len] = '\n';
	cp[new_len + 1] = '\0';
}

#endif /* USE_PAM */
Commit	Line	Data
a5c9cd31	1	/*
09564242	2	* Copyright (c) 2000 Damien Miller. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
09564242	12	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
a5c9cd31	23	*/
	24
	25	#include "includes.h"
	26
	27	#ifdef USE_PAM
	28	#include "ssh.h"
	29	#include "xmalloc.h"
42f11eb2	30	#include "log.h"
fde58bd4	31	#include "auth.h"
277f55cf	32	#include "auth-options.h"
5c377b3b	33	#include "auth-pam.h"
a5c9cd31	34	#include "servconf.h"
42f11eb2	35	#include "canohost.h"
42f11eb2	36	#include "readpass.h"
a5c9cd31	37
1ddee76b	38	extern char *__progname;
1ddee76b	39
277f55cf	40	extern int use_privsep;
277f55cf	41
a5c9cd31	42	RCSID("$Id$");
a5c9cd31	43
5daf7064	44	#define NEW_AUTHTOK_MSG \
b992432e	45	"Warning: Your password has expired, please change it now."
277f55cf	46	#define NEW_AUTHTOK_MSG_PRIVSEP \
277f55cf	47	"Your password has expired, the session cannot proceed."
5daf7064	48
5c377b3b	49	static int do_pam_conversation(int num_msg, const struct pam_message **msg,
5c377b3b	50	struct pam_response *resp, void appdata_ptr);
a5c9cd31	51
	52	/* module-local variables */
	53	static struct pam_conv conv = {
f7808a93	54	(int (*)())do_pam_conversation,
a5c9cd31	55	NULL
a5c9cd31	56	};
e11aab29	57	static char *__pam_msg = NULL;
	58	static pam_handle_t *__pamh = NULL;
	59	static const char *__pampasswd = NULL;
a5c9cd31	60
5c377b3b	61	/* states for do_pam_conversation() */
8c9fe09e	62	enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
b992432e	63	/* remember whether pam_acct_mgmt() returned PAM_NEW_AUTHTOK_REQD */
ad55cd03	64	static int password_change_required = 0;
8c9fe09e	65	/* remember whether the last pam_authenticate() succeeded or not */
	66	static int was_authenticated = 0;
	67
e11aab29	68	/* Remember what has been initialised */
	69	static int session_opened = 0;
	70	static int creds_set = 0;
	71
8c9fe09e	72	/* accessor which allows us to switch conversation structs according to
8c9fe09e	73	* the authentication method being used */
e11aab29	74	void do_pam_set_conv(struct pam_conv *conv)
8c9fe09e	75	{
e11aab29	76	pam_set_item(__pamh, PAM_CONV, conv);
8c9fe09e	77	}
	78
	79	/* start an authentication run */
	80	int do_pam_authenticate(int flags)
	81	{
e11aab29	82	int retval = pam_authenticate(__pamh, flags);
8c9fe09e	83	was_authenticated = (retval == PAM_SUCCESS);
	84	return retval;
	85	}
ad55cd03	86
	87	/*
	88	* PAM conversation function.
	89	* There are two states this can run in.
	90	*
	91	* INITIAL_LOGIN mode simply feeds the password from the client into
	92	* PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
e11aab29	93	* messages with into __pam_msg. This is used during initial
ad55cd03	94	* authentication to bypass the normal PAM password prompt.
ad55cd03	95	*
9678565b	96	* OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase()
ad55cd03	97	* and outputs messages to stderr. This mode is used if pam_chauthtok()
	98	* is called to update expired passwords.
	99	*/
5c377b3b	100	static int do_pam_conversation(int num_msg, const struct pam_message **msg,
a5c9cd31	101	struct pam_response *resp, void appdata_ptr)
	102	{
	103	struct pam_response *reply;
	104	int count;
ad55cd03	105	char buf[1024];
a5c9cd31	106
a5c9cd31	107	/* PAM will free this later */
b2f295dc	108	reply = xmalloc(num_msg * sizeof(*reply));
a5c9cd31	109
ad55cd03	110	for (count = 0; count < num_msg; count++) {
5c377b3b	111	if (pamstate == INITIAL_LOGIN) {
	112	/*
	113	* We can't use stdio yet, queue messages for
	114	* printing later
	115	*/
	116	switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
ad55cd03	117	case PAM_PROMPT_ECHO_ON:
b2f295dc	118	xfree(reply);
5c377b3b	119	return PAM_CONV_ERR;
5c377b3b	120	case PAM_PROMPT_ECHO_OFF:
e11aab29	121	if (__pampasswd == NULL) {
b2f295dc	122	xfree(reply);
71dfaf1c	123	return PAM_CONV_ERR;
71dfaf1c	124	}
e11aab29	125	reply[count].resp = xstrdup(__pampasswd);
a5c9cd31	126	reply[count].resp_retcode = PAM_SUCCESS;
a5c9cd31	127	break;
ad55cd03	128	case PAM_ERROR_MSG:
a5c9cd31	129	case PAM_TEXT_INFO:
b2f295dc	130	if (PAM_MSG_MEMBER(msg, count, msg) != NULL) {
e11aab29	131	message_cat(&__pam_msg,
5c377b3b	132	PAM_MSG_MEMBER(msg, count, msg));
ad55cd03	133	}
a5c9cd31	134	reply[count].resp = xstrdup("");
ad55cd03	135	reply[count].resp_retcode = PAM_SUCCESS;
a5c9cd31	136	break;
a5c9cd31	137	default:
b2f295dc	138	xfree(reply);
a5c9cd31	139	return PAM_CONV_ERR;
5c377b3b	140	}
	141	} else {
	142	/*
	143	* stdio is connected, so interact directly
	144	*/
	145	switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
	146	case PAM_PROMPT_ECHO_ON:
	147	fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
	148	fgets(buf, sizeof(buf), stdin);
	149	reply[count].resp = xstrdup(buf);
	150	reply[count].resp_retcode = PAM_SUCCESS;
	151	break;
	152	case PAM_PROMPT_ECHO_OFF:
9678565b	153	reply[count].resp =
840ad55e	154	read_passphrase(PAM_MSG_MEMBER(msg, count,
840ad55e	155	msg), RP_ALLOW_STDIN);
5c377b3b	156	reply[count].resp_retcode = PAM_SUCCESS;
	157	break;
	158	case PAM_ERROR_MSG:
	159	case PAM_TEXT_INFO:
	160	if ((*msg)[count].msg != NULL)
	161	fprintf(stderr, "%s\n",
	162	PAM_MSG_MEMBER(msg, count, msg));
	163	reply[count].resp = xstrdup("");
	164	reply[count].resp_retcode = PAM_SUCCESS;
	165	break;
	166	default:
b2f295dc	167	xfree(reply);
5c377b3b	168	return PAM_CONV_ERR;
5c377b3b	169	}
a5c9cd31	170	}
	171	}
	172
	173	*resp = reply;
	174
	175	return PAM_SUCCESS;
	176	}
	177
	178	/* Called at exit to cleanly shutdown PAM */
e11aab29	179	void do_pam_cleanup_proc(void *context)
a5c9cd31	180	{
37eadb90	181	int pam_retval = PAM_SUCCESS;
a5c9cd31	182
e11aab29	183	if (__pamh && session_opened) {
e11aab29	184	pam_retval = pam_close_session(__pamh, 0);
5c377b3b	185	if (pam_retval != PAM_SUCCESS)
2b87da3b	186	log("Cannot close PAM session[%d]: %.200s",
e11aab29	187	pam_retval, PAM_STRERROR(__pamh, pam_retval));
1c2d0a13	188	}
a5c9cd31	189
e11aab29	190	if (__pamh && creds_set) {
e11aab29	191	pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED);
5c377b3b	192	if (pam_retval != PAM_SUCCESS)
5c377b3b	193	debug("Cannot delete credentials[%d]: %.200s",
e11aab29	194	pam_retval, PAM_STRERROR(__pamh, pam_retval));
1c2d0a13	195	}
a5c9cd31	196
e11aab29	197	if (__pamh) {
e11aab29	198	pam_retval = pam_end(__pamh, pam_retval);
5c377b3b	199	if (pam_retval != PAM_SUCCESS)
2b87da3b	200	log("Cannot release PAM authentication[%d]: %.200s",
e11aab29	201	pam_retval, PAM_STRERROR(__pamh, pam_retval));
a5c9cd31	202	}
	203	}
	204
	205	/* Attempt password authentation using PAM */
fde58bd4	206	int auth_pam_password(Authctxt authctxt, const char password)
a5c9cd31	207	{
	208	extern ServerOptions options;
	209	int pam_retval;
fde58bd4	210	struct passwd *pw = authctxt->pw;
a5c9cd31	211
e11aab29	212	do_pam_set_conv(&conv);
8c9fe09e	213
a5c9cd31	214	/* deny if no user. */
	215	if (pw == NULL)
	216	return 0;
3cc990d7	217	if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD)
a5c9cd31	218	return 0;
	219	if (*password == '\0' && options.permit_empty_passwd == 0)
	220	return 0;
	221
e11aab29	222	__pampasswd = password;
2b87da3b	223
ad55cd03	224	pamstate = INITIAL_LOGIN;
78afd1dc	225	pam_retval = do_pam_authenticate(
78afd1dc	226	options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0);
a5c9cd31	227	if (pam_retval == PAM_SUCCESS) {
5c377b3b	228	debug("PAM Password authentication accepted for "
5c377b3b	229	"user \"%.100s\"", pw->pw_name);
a5c9cd31	230	return 1;
a5c9cd31	231	} else {
5c377b3b	232	debug("PAM Password authentication for \"%.100s\" "
5c377b3b	233	"failed[%d]: %s", pw->pw_name, pam_retval,
e11aab29	234	PAM_STRERROR(__pamh, pam_retval));
a5c9cd31	235	return 0;
	236	}
	237	}
	238
	239	/* Do account management using PAM */
	240	int do_pam_account(char username, char remote_user)
	241	{
	242	int pam_retval;
2b87da3b	243
e11aab29	244	do_pam_set_conv(&conv);
5c377b3b	245
5c377b3b	246	if (remote_user) {
a5c9cd31	247	debug("PAM setting ruser to \"%.200s\"", remote_user);
e11aab29	248	pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user);
5c377b3b	249	if (pam_retval != PAM_SUCCESS)
5c377b3b	250	fatal("PAM set ruser failed[%d]: %.200s", pam_retval,
e11aab29	251	PAM_STRERROR(__pamh, pam_retval));
a5c9cd31	252	}
a5c9cd31	253
e11aab29	254	pam_retval = pam_acct_mgmt(__pamh, 0);
ad200abb	255	debug2("pam_acct_mgmt() = %d", pam_retval);
5daf7064	256	switch (pam_retval) {
	257	case PAM_SUCCESS:
	258	/* This is what we want */
	259	break;
e108cd93	260	#if 0
5daf7064	261	case PAM_NEW_AUTHTOK_REQD:
277f55cf	262	message_cat(&__pam_msg, use_privsep ?
277f55cf	263	NEW_AUTHTOK_MSG_PRIVSEP : NEW_AUTHTOK_MSG);
ad55cd03	264	/* flag that password change is necessary */
ad55cd03	265	password_change_required = 1;
277f55cf	266	/* disallow other functionality for now */
	267	no_port_forwarding_flag \|= 2;
	268	no_agent_forwarding_flag \|= 2;
	269	no_x11_forwarding_flag \|= 2;
5daf7064	270	break;
e108cd93	271	#endif
5daf7064	272	default:
5c377b3b	273	log("PAM rejected by account configuration[%d]: "
e11aab29	274	"%.200s", pam_retval, PAM_STRERROR(__pamh,
5c377b3b	275	pam_retval));
5daf7064	276	return(0);
a5c9cd31	277	}
2b87da3b	278
a5c9cd31	279	return(1);
	280	}
	281
	282	/* Do PAM-specific session initialisation */
fd094f49	283	void do_pam_session(char username, const char ttyname)
a5c9cd31	284	{
	285	int pam_retval;
	286
5f404be3	287	do_pam_set_conv(&conv);
5f404be3	288
a5c9cd31	289	if (ttyname != NULL) {
a5c9cd31	290	debug("PAM setting tty to \"%.200s\"", ttyname);
e11aab29	291	pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname);
5c377b3b	292	if (pam_retval != PAM_SUCCESS)
2b87da3b	293	fatal("PAM set tty failed[%d]: %.200s",
e11aab29	294	pam_retval, PAM_STRERROR(__pamh, pam_retval));
a5c9cd31	295	}
a5c9cd31	296
e11aab29	297	pam_retval = pam_open_session(__pamh, 0);
5c377b3b	298	if (pam_retval != PAM_SUCCESS)
2b87da3b	299	fatal("PAM session setup failed[%d]: %.200s",
e11aab29	300	pam_retval, PAM_STRERROR(__pamh, pam_retval));
40a35ff1	301
1c2d0a13	302	session_opened = 1;
a5c9cd31	303	}
a5c9cd31	304
2b87da3b	305	/* Set PAM credentials */
9afbfcfa	306	void do_pam_setcred(int init)
a5c9cd31	307	{
a5c9cd31	308	int pam_retval;
2b87da3b	309
39ce53de	310	if (__pamh == NULL)
	311	return;
	312
5f404be3	313	do_pam_set_conv(&conv);
5f404be3	314
a5c9cd31	315	debug("PAM establishing creds");
9afbfcfa	316	pam_retval = pam_setcred(__pamh,
9afbfcfa	317	init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED);
5daf7064	318	if (pam_retval != PAM_SUCCESS) {
5c377b3b	319	if (was_authenticated)
2b87da3b	320	fatal("PAM setcred failed[%d]: %.200s",
e11aab29	321	pam_retval, PAM_STRERROR(__pamh, pam_retval));
5c377b3b	322	else
2b87da3b	323	debug("PAM setcred failed[%d]: %.200s",
e11aab29	324	pam_retval, PAM_STRERROR(__pamh, pam_retval));
1c2d0a13	325	} else
1c2d0a13	326	creds_set = 1;
ad55cd03	327	}
ad55cd03	328
2919e060	329	/* accessor function for file scope static variable */
e11aab29	330	int is_pam_password_change_required(void)
2919e060	331	{
	332	return password_change_required;
	333	}
	334
2b87da3b	335	/*
ad55cd03	336	* Have user change authentication token if pam_acct_mgmt() indicated
	337	* it was expired. This needs to be called after an interactive
	338	* session is established and the user's pty is connected to
b992432e	339	* stdin/stdout/stderr.
ad55cd03	340	*/
a815d7a3	341	void do_pam_chauthtok(void)
ad55cd03	342	{
	343	int pam_retval;
	344
5f404be3	345	do_pam_set_conv(&conv);
5f404be3	346
ad55cd03	347	if (password_change_required) {
277f55cf	348	if (use_privsep)
	349	fatal("Password changing is currently unsupported"
	350	" with privilege separation");
ad55cd03	351	pamstate = OTHER;
0a3700ee	352	pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
	353	if (pam_retval != PAM_SUCCESS)
	354	fatal("PAM pam_chauthtok failed[%d]: %.200s",
	355	pam_retval, PAM_STRERROR(__pamh, pam_retval));
277f55cf	356	#if 0
	357	/* XXX: This would need to be done in the parent process,
	358	* but there's currently no way to pass such request. */
	359	no_port_forwarding_flag &= ~2;
	360	no_agent_forwarding_flag &= ~2;
	361	no_x11_forwarding_flag &= ~2;
	362	if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
	363	channel_permit_all_opens();
	364	#endif
5daf7064	365	}
a5c9cd31	366	}
	367
	368	/* Cleanly shutdown PAM */
	369	void finish_pam(void)
	370	{
e11aab29	371	do_pam_cleanup_proc(NULL);
e11aab29	372	fatal_remove_cleanup(&do_pam_cleanup_proc, NULL);
a5c9cd31	373	}
	374
	375	/* Start PAM authentication for specified account */
04fc7a67	376	void start_pam(const char *user)
a5c9cd31	377	{
a5c9cd31	378	int pam_retval;
dbd97a4d	379	extern ServerOptions options;
46c76c63	380	extern u_int utmp_len;
46c76c63	381	const char *rhost;
a5c9cd31	382
04fc7a67	383	debug("Starting up PAM with username \"%.200s\"", user);
a5c9cd31	384
e11aab29	385	pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh);
a5c9cd31	386
5c377b3b	387	if (pam_retval != PAM_SUCCESS)
2b87da3b	388	fatal("PAM initialisation failed[%d]: %.200s",
e11aab29	389	pam_retval, PAM_STRERROR(__pamh, pam_retval));
e275684f	390
983784a1	391	rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping);
46c76c63	392	debug("PAM setting rhost to \"%.200s\"", rhost);
	393
	394	pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost);
e275684f	395	if (pam_retval != PAM_SUCCESS)
e275684f	396	fatal("PAM set rhost failed[%d]: %.200s", pam_retval,
e11aab29	397	PAM_STRERROR(__pamh, pam_retval));
a8545c6c	398	#ifdef PAM_TTY_KLUDGE
ae543aaa	399	/*
ae543aaa	400	* Some PAM modules (e.g. pam_time) require a TTY to operate,
2b87da3b	401	* and will fail in various stupid ways if they don't get one.
ae543aaa	402	* sshd doesn't set the tty until too late in the auth process and may
ae543aaa	403	* not even need one (for tty-less connections)
2b87da3b	404	* Kludge: Set a fake PAM_TTY
ae543aaa	405	*/
9f214051	406	pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh");
5c377b3b	407	if (pam_retval != PAM_SUCCESS)
2b87da3b	408	fatal("PAM set tty failed[%d]: %.200s",
e11aab29	409	pam_retval, PAM_STRERROR(__pamh, pam_retval));
a8545c6c	410	#endif /* PAM_TTY_KLUDGE */
cbd7492e	411
e11aab29	412	fatal_add_cleanup(&do_pam_cleanup_proc, NULL);
a5c9cd31	413	}
	414
	415	/* Return list of PAM enviornment strings */
	416	char **fetch_pam_environment(void)
	417	{
2b763e31	418	#ifdef HAVE_PAM_GETENVLIST
e11aab29	419	return(pam_getenvlist(__pamh));
2b763e31	420	#else /* HAVE_PAM_GETENVLIST */
	421	return(NULL);
	422	#endif /* HAVE_PAM_GETENVLIST */
a5c9cd31	423	}
	424
	425	/* Print any messages that have been generated during authentication */
	426	/* or account checking to stderr */
	427	void print_pam_messages(void)
	428	{
e11aab29	429	if (__pam_msg != NULL)
e11aab29	430	fputs(__pam_msg, stderr);
5daf7064	431	}
5daf7064	432
5c377b3b	433	/* Append a message to buffer */
5c377b3b	434	void message_cat(char *p, const char a)
5daf7064	435	{
5c377b3b	436	char *cp;
5c377b3b	437	size_t new_len;
2b87da3b	438
5c377b3b	439	new_len = strlen(a);
2b87da3b	440
5c377b3b	441	if (*p) {
	442	size_t len = strlen(*p);
	443
	444	p = xrealloc(p, new_len + len + 2);
	445	cp = *p + len;
	446	} else
	447	*p = cp = xmalloc(new_len + 2);
5daf7064	448
5c377b3b	449	memcpy(cp, a, new_len);
	450	cp[new_len] = '\n';
	451	cp[new_len + 1] = '\0';
a5c9cd31	452	}
	453
	454	#endif /* USE_PAM */