[openssh.git] / auth2-chall.c

/*
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 * Copyright (c) 2001 Per Allansson.  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"
RCSID("$OpenBSD: auth2-chall.c,v 1.12 2001/12/28 12:14:27 markus Exp $");

#include "ssh2.h"
#include "auth.h"
#include "packet.h"
#include "xmalloc.h"
#include "dispatch.h"
#include "auth.h"
#include "log.h"

static int auth2_challenge_start(Authctxt *);
static int send_userauth_info_request(Authctxt *);
static void input_userauth_info_response(int, int, u_int32_t, void *);

#ifdef BSD_AUTH
extern KbdintDevice bsdauth_device;
#else
#ifdef SKEY
extern KbdintDevice skey_device;
#endif
#endif

KbdintDevice *devices[] = {
#ifdef BSD_AUTH
	&bsdauth_device,
#else
#ifdef SKEY
	&skey_device,
#endif
#endif
	NULL
};

typedef struct KbdintAuthctxt KbdintAuthctxt;
struct KbdintAuthctxt
{
	char *devices;
	void *ctxt;
	KbdintDevice *device;
};

static KbdintAuthctxt *
kbdint_alloc(const char *devs)
{
	KbdintAuthctxt *kbdintctxt;
	int i;
	char buf[1024];

	kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
	if (strcmp(devs, "") == 0) {
		buf[0] = '\0';
		for (i = 0; devices[i]; i++) {
			if (i != 0)
				strlcat(buf, ",", sizeof(buf));
			strlcat(buf, devices[i]->name, sizeof(buf));
		}
		debug("kbdint_alloc: devices '%s'", buf);
		kbdintctxt->devices = xstrdup(buf);
	} else {
		kbdintctxt->devices = xstrdup(devs);
	}
	kbdintctxt->ctxt = NULL;
	kbdintctxt->device = NULL;

	return kbdintctxt;
}
static void
kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
{
	if (kbdintctxt->ctxt) {
		kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
		kbdintctxt->ctxt = NULL;
	}
	kbdintctxt->device = NULL;
}
static void
kbdint_free(KbdintAuthctxt *kbdintctxt)
{
	if (kbdintctxt->device)
		kbdint_reset_device(kbdintctxt);
	if (kbdintctxt->devices) {
		xfree(kbdintctxt->devices);
		kbdintctxt->devices = NULL;
	}
	xfree(kbdintctxt);
}
/* get next device */
static int
kbdint_next_device(KbdintAuthctxt *kbdintctxt)
{
	size_t len;
	char *t;
	int i;

	if (kbdintctxt->device)
		kbdint_reset_device(kbdintctxt);
	do {
		len = kbdintctxt->devices ?
		    strcspn(kbdintctxt->devices, ",") : 0;

		if (len == 0)
			break;
		for (i = 0; devices[i]; i++)
			if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
				kbdintctxt->device = devices[i];
		t = kbdintctxt->devices;
		kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
		xfree(t);
		debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
		   kbdintctxt->devices : "<empty>");
	} while (kbdintctxt->devices && !kbdintctxt->device);

	return kbdintctxt->device ? 1 : 0;
}

/*
 * try challenge-response, set authctxt->postponed if we have to
 * wait for the response.
 */
int
auth2_challenge(Authctxt *authctxt, char *devs)
{
	debug("auth2_challenge: user=%s devs=%s",
	    authctxt->user ? authctxt->user : "<nouser>",
	    devs ? devs : "<no devs>");

	if (authctxt->user == NULL || !devs)
		return 0;
	if (authctxt->kbdintctxt == NULL)
		authctxt->kbdintctxt = kbdint_alloc(devs);
	return auth2_challenge_start(authctxt);
}

/* unregister kbd-int callbacks and context */
void
auth2_challenge_stop(Authctxt *authctxt)
{
	/* unregister callback */
	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
	if (authctxt->kbdintctxt != NULL)  {
		kbdint_free(authctxt->kbdintctxt);
		authctxt->kbdintctxt = NULL;
	}
}

/* side effect: sets authctxt->postponed if a reply was sent*/
static int
auth2_challenge_start(Authctxt *authctxt)
{
	KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;

	debug2("auth2_challenge_start: devices %s",
	    kbdintctxt->devices ?  kbdintctxt->devices : "<empty>");

	if (kbdint_next_device(kbdintctxt) == 0) {
		auth2_challenge_stop(authctxt);
		return 0;
	}
	debug("auth2_challenge_start: trying authentication method '%s'",
	    kbdintctxt->device->name);

	if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
		auth2_challenge_stop(authctxt);
		return 0;
	}
	if (send_userauth_info_request(authctxt) == 0) {
		auth2_challenge_stop(authctxt);
		return 0;
	}
	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
	    &input_userauth_info_response);

	authctxt->postponed = 1;
	return 0;
}

static int
send_userauth_info_request(Authctxt *authctxt)
{
	KbdintAuthctxt *kbdintctxt;
	char *name, *instr, **prompts;
	int i;
	u_int numprompts, *echo_on;

	kbdintctxt = authctxt->kbdintctxt;
	if (kbdintctxt->device->query(kbdintctxt->ctxt,
	    &name, &instr, &numprompts, &prompts, &echo_on))
		return 0;

	packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
	packet_put_cstring(name);
	packet_put_cstring(instr);
	packet_put_cstring(""); 	/* language not used */
	packet_put_int(numprompts);
	for (i = 0; i < numprompts; i++) {
		packet_put_cstring(prompts[i]);
		packet_put_char(echo_on[i]);
	}
	packet_send();
	packet_write_wait();

	for (i = 0; i < numprompts; i++)
		xfree(prompts[i]);
	xfree(prompts);
	xfree(echo_on);
	xfree(name);
	xfree(instr);
	return 1;
}

static void
input_userauth_info_response(int type, int plen, u_int32_t seq, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	KbdintAuthctxt *kbdintctxt;
	int i, authenticated = 0, res, len;
	u_int nresp;
	char **response = NULL, *method;

	if (authctxt == NULL)
		fatal("input_userauth_info_response: no authctxt");
	kbdintctxt = authctxt->kbdintctxt;
	if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
		fatal("input_userauth_info_response: no kbdintctxt");
	if (kbdintctxt->device == NULL)
		fatal("input_userauth_info_response: no device");

	authctxt->postponed = 0;	/* reset */
	nresp = packet_get_int();
	if (nresp > 0) {
		response = xmalloc(nresp * sizeof(char*));
		for (i = 0; i < nresp; i++)
			response[i] = packet_get_string(NULL);
	}
	packet_check_eom();

	if (authctxt->valid) {
		res = kbdintctxt->device->respond(kbdintctxt->ctxt,
		    nresp, response);
	} else {
		res = -1;
	}

	for (i = 0; i < nresp; i++) {
		memset(response[i], 'r', strlen(response[i]));
		xfree(response[i]);
	}
	if (response)
		xfree(response);

	switch (res) {
	case 0:
		/* Success! */
		authenticated = 1;
		break;
	case 1:
		/* Authentication needs further interaction */
		if (send_userauth_info_request(authctxt) == 1)
			authctxt->postponed = 1;
		break;
	default:
		/* Failure! */
		break;
	}

	len = strlen("keyboard-interactive") + 2 +
		strlen(kbdintctxt->device->name);
	method = xmalloc(len);
	method[0] = '\0';
	strlcat(method, "keyboard-interactive", len);
	strlcat(method, "/", len);
	strlcat(method, kbdintctxt->device->name, len);

	if (!authctxt->postponed) {
		if (authenticated) {
			auth2_challenge_stop(authctxt);
		} else {
			/* start next device */
			/* may set authctxt->postponed */
			auth2_challenge_start(authctxt);
		}
	}
	userauth_finish(authctxt, authenticated, method);
	xfree(method);
}
Commit	Line	Data
59c97189	1	/*
f3c7c613	2	* Copyright (c) 2001 Markus Friedl. All rights reserved.
5ba55ada	3	* Copyright (c) 2001 Per Allansson. All rights reserved.
59c97189	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	17	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	24	*/
	25	#include "includes.h"
95500969	26	RCSID("$OpenBSD: auth2-chall.c,v 1.12 2001/12/28 12:14:27 markus Exp $");
59c97189	27
59c97189	28	#include "ssh2.h"
	29	#include "auth.h"
	30	#include "packet.h"
	31	#include "xmalloc.h"
	32	#include "dispatch.h"
5ba55ada	33	#include "auth.h"
42f11eb2	34	#include "log.h"
59c97189	35
396c147e	36	static int auth2_challenge_start(Authctxt *);
396c147e	37	static int send_userauth_info_request(Authctxt *);
24ca6821	38	static void input_userauth_info_response(int, int, u_int32_t, void *);
5ba55ada	39
	40	#ifdef BSD_AUTH
	41	extern KbdintDevice bsdauth_device;
	42	#else
	43	#ifdef SKEY
	44	extern KbdintDevice skey_device;
	45	#endif
	46	#endif
	47
	48	KbdintDevice *devices[] = {
	49	#ifdef BSD_AUTH
	50	&bsdauth_device,
	51	#else
	52	#ifdef SKEY
	53	&skey_device,
	54	#endif
	55	#endif
	56	NULL
	57	};
	58
	59	typedef struct KbdintAuthctxt KbdintAuthctxt;
	60	struct KbdintAuthctxt
	61	{
	62	char *devices;
	63	void *ctxt;
	64	KbdintDevice *device;
	65	};
	66
396c147e	67	static KbdintAuthctxt *
5ba55ada	68	kbdint_alloc(const char *devs)
	69	{
	70	KbdintAuthctxt *kbdintctxt;
	71	int i;
	72	char buf[1024];
	73
	74	kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
	75	if (strcmp(devs, "") == 0) {
	76	buf[0] = '\0';
	77	for (i = 0; devices[i]; i++) {
	78	if (i != 0)
	79	strlcat(buf, ",", sizeof(buf));
	80	strlcat(buf, devices[i]->name, sizeof(buf));
	81	}
	82	debug("kbdint_alloc: devices '%s'", buf);
	83	kbdintctxt->devices = xstrdup(buf);
	84	} else {
	85	kbdintctxt->devices = xstrdup(devs);
	86	}
	87	kbdintctxt->ctxt = NULL;
	88	kbdintctxt->device = NULL;
	89
	90	return kbdintctxt;
	91	}
396c147e	92	static void
5ba55ada	93	kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
	94	{
	95	if (kbdintctxt->ctxt) {
	96	kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
	97	kbdintctxt->ctxt = NULL;
	98	}
	99	kbdintctxt->device = NULL;
	100	}
396c147e	101	static void
5ba55ada	102	kbdint_free(KbdintAuthctxt *kbdintctxt)
	103	{
	104	if (kbdintctxt->device)
	105	kbdint_reset_device(kbdintctxt);
	106	if (kbdintctxt->devices) {
	107	xfree(kbdintctxt->devices);
	108	kbdintctxt->devices = NULL;
	109	}
	110	xfree(kbdintctxt);
	111	}
	112	/* get next device */
396c147e	113	static int
5ba55ada	114	kbdint_next_device(KbdintAuthctxt *kbdintctxt)
	115	{
	116	size_t len;
	117	char *t;
	118	int i;
	119
	120	if (kbdintctxt->device)
	121	kbdint_reset_device(kbdintctxt);
	122	do {
	123	len = kbdintctxt->devices ?
	124	strcspn(kbdintctxt->devices, ",") : 0;
	125
	126	if (len == 0)
	127	break;
	128	for (i = 0; devices[i]; i++)
	129	if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
	130	kbdintctxt->device = devices[i];
	131	t = kbdintctxt->devices;
	132	kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
	133	xfree(t);
	134	debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
	135	kbdintctxt->devices : "<empty>");
	136	} while (kbdintctxt->devices && !kbdintctxt->device);
	137
	138	return kbdintctxt->device ? 1 : 0;
	139	}
59c97189	140
59c97189	141	/*
aa8003d6	142	* try challenge-response, set authctxt->postponed if we have to
59c97189	143	* wait for the response.
	144	*/
	145	int
	146	auth2_challenge(Authctxt authctxt, char devs)
	147	{
5ba55ada	148	debug("auth2_challenge: user=%s devs=%s",
	149	authctxt->user ? authctxt->user : "<nouser>",
	150	devs ? devs : "<no devs>");
	151
f5e69c65	152	if (authctxt->user == NULL \|\| !devs)
5ba55ada	153	return 0;
184eed6a	154	if (authctxt->kbdintctxt == NULL)
5ba55ada	155	authctxt->kbdintctxt = kbdint_alloc(devs);
	156	return auth2_challenge_start(authctxt);
	157	}
	158
2f293d43	159	/* unregister kbd-int callbacks and context */
	160	void
	161	auth2_challenge_stop(Authctxt *authctxt)
	162	{
	163	/* unregister callback */
	164	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
	165	if (authctxt->kbdintctxt != NULL) {
	166	kbdint_free(authctxt->kbdintctxt);
	167	authctxt->kbdintctxt = NULL;
	168	}
	169	}
	170
5ba55ada	171	/* side effect: sets authctxt->postponed if a reply was sent*/
	172	static int
	173	auth2_challenge_start(Authctxt *authctxt)
	174	{
	175	KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
	176
	177	debug2("auth2_challenge_start: devices %s",
	178	kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
	179
	180	if (kbdint_next_device(kbdintctxt) == 0) {
2f293d43	181	auth2_challenge_stop(authctxt);
5ba55ada	182	return 0;
	183	}
	184	debug("auth2_challenge_start: trying authentication method '%s'",
	185	kbdintctxt->device->name);
59c97189	186
5ba55ada	187	if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
2f293d43	188	auth2_challenge_stop(authctxt);
59c97189	189	return 0;
5ba55ada	190	}
5ba55ada	191	if (send_userauth_info_request(authctxt) == 0) {
2f293d43	192	auth2_challenge_stop(authctxt);
59c97189	193	return 0;
5ba55ada	194	}
59c97189	195	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
59c97189	196	&input_userauth_info_response);
5ba55ada	197
59c97189	198	authctxt->postponed = 1;
	199	return 0;
	200	}
	201
5ba55ada	202	static int
5ba55ada	203	send_userauth_info_request(Authctxt *authctxt)
59c97189	204	{
5ba55ada	205	KbdintAuthctxt *kbdintctxt;
	206	char name, instr, **prompts;
	207	int i;
	208	u_int numprompts, *echo_on;
	209
	210	kbdintctxt = authctxt->kbdintctxt;
	211	if (kbdintctxt->device->query(kbdintctxt->ctxt,
	212	&name, &instr, &numprompts, &prompts, &echo_on))
	213	return 0;
59c97189	214
59c97189	215	packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
5ba55ada	216	packet_put_cstring(name);
	217	packet_put_cstring(instr);
	218	packet_put_cstring(""); /* language not used */
	219	packet_put_int(numprompts);
	220	for (i = 0; i < numprompts; i++) {
	221	packet_put_cstring(prompts[i]);
	222	packet_put_char(echo_on[i]);
	223	}
59c97189	224	packet_send();
59c97189	225	packet_write_wait();
5ba55ada	226
	227	for (i = 0; i < numprompts; i++)
	228	xfree(prompts[i]);
	229	xfree(prompts);
	230	xfree(echo_on);
	231	xfree(name);
	232	xfree(instr);
	233	return 1;
59c97189	234	}
59c97189	235
5ba55ada	236	static void
24ca6821	237	input_userauth_info_response(int type, int plen, u_int32_t seq, void *ctxt)
59c97189	238	{
59c97189	239	Authctxt *authctxt = ctxt;
5ba55ada	240	KbdintAuthctxt *kbdintctxt;
	241	int i, authenticated = 0, res, len;
	242	u_int nresp;
	243	char *response = NULL, method;
59c97189	244
	245	if (authctxt == NULL)
	246	fatal("input_userauth_info_response: no authctxt");
5ba55ada	247	kbdintctxt = authctxt->kbdintctxt;
	248	if (kbdintctxt == NULL \|\| kbdintctxt->ctxt == NULL)
	249	fatal("input_userauth_info_response: no kbdintctxt");
	250	if (kbdintctxt->device == NULL)
	251	fatal("input_userauth_info_response: no device");
59c97189	252
	253	authctxt->postponed = 0; /* reset */
	254	nresp = packet_get_int();
5ba55ada	255	if (nresp > 0) {
	256	response = xmalloc(nresp * sizeof(char*));
	257	for (i = 0; i < nresp; i++)
	258	response[i] = packet_get_string(NULL);
	259	}
95500969	260	packet_check_eom();
5ba55ada	261
	262	if (authctxt->valid) {
	263	res = kbdintctxt->device->respond(kbdintctxt->ctxt,
	264	nresp, response);
	265	} else {
	266	res = -1;
	267	}
	268
	269	for (i = 0; i < nresp; i++) {
	270	memset(response[i], 'r', strlen(response[i]));
	271	xfree(response[i]);
	272	}
	273	if (response)
59c97189	274	xfree(response);
5ba55ada	275
	276	switch (res) {
	277	case 0:
	278	/* Success! */
	279	authenticated = 1;
	280	break;
	281	case 1:
	282	/* Authentication needs further interaction */
2f293d43	283	if (send_userauth_info_request(authctxt) == 1)
2f293d43	284	authctxt->postponed = 1;
5ba55ada	285	break;
	286	default:
	287	/* Failure! */
	288	break;
59c97189	289	}
5ba55ada	290
	291	len = strlen("keyboard-interactive") + 2 +
	292	strlen(kbdintctxt->device->name);
	293	method = xmalloc(len);
	294	method[0] = '\0';
	295	strlcat(method, "keyboard-interactive", len);
	296	strlcat(method, "/", len);
	297	strlcat(method, kbdintctxt->device->name, len);
	298
	299	if (!authctxt->postponed) {
5ba55ada	300	if (authenticated) {
2f293d43	301	auth2_challenge_stop(authctxt);
5ba55ada	302	} else {
	303	/* start next device */
	304	/* may set authctxt->postponed */
	305	auth2_challenge_start(authctxt);
	306	}
	307	}
d9cd3575	308	userauth_finish(authctxt, authenticated, method);
5ba55ada	309	xfree(method);
59c97189	310	}