[gssapi-openssh.git] / openssh / 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 1.8 2001/09/27 15:31:17 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, 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);
}

/* 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) {
		kbdint_free(kbdintctxt);
		authctxt->kbdintctxt = NULL;
		return 0;
	}
	debug("auth2_challenge_start: trying authentication method '%s'",
	    kbdintctxt->device->name);

	if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
		kbdint_free(kbdintctxt);
		authctxt->kbdintctxt = NULL;
		return 0;
	}
	if (send_userauth_info_request(authctxt) == 0) {
		kbdint_free(kbdintctxt);
		authctxt->kbdintctxt = NULL;
		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, 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_done();

	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 */
		authctxt->postponed = 1;
		if (send_userauth_info_request(authctxt) == 0) {
			authctxt->postponed = 0;
		}
		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) {
		/* unregister callback */
		dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);

		if (authenticated) {
			kbdint_free(kbdintctxt);
			authctxt->kbdintctxt = NULL;
		} else {
			/* start next device */
			/* may set authctxt->postponed */
			auth2_challenge_start(authctxt);
		}
	}
	userauth_finish(authctxt, authenticated, method);
	xfree(method);
}
Commit	Line	Data
3c0ef626	1	/*
	2	* Copyright (c) 2001 Markus Friedl. All rights reserved.
	3	* Copyright (c) 2001 Per Allansson. All rights reserved.
	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"
	26	RCSID("$OpenBSD: auth2-chall.c,v 1.8 2001/09/27 15:31:17 markus Exp $");
	27
	28	#include "ssh2.h"
	29	#include "auth.h"
	30	#include "packet.h"
	31	#include "xmalloc.h"
	32	#include "dispatch.h"
	33	#include "auth.h"
	34	#include "log.h"
	35
	36	static int auth2_challenge_start(Authctxt *);
	37	static int send_userauth_info_request(Authctxt *);
	38	static void input_userauth_info_response(int, int, void *);
	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
67	static KbdintAuthctxt *
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	}
92	static void
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	}
101	static void
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 */
113	static int
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	}
140
141	/*
142	* try challenge-response, set authctxt->postponed if we have to
143	* wait for the response.
144	*/
145	int
146	auth2_challenge(Authctxt authctxt, char devs)
147	{
148	debug("auth2_challenge: user=%s devs=%s",
149	authctxt->user ? authctxt->user : "<nouser>",
150	devs ? devs : "<no devs>");
151
152	if (authctxt->user == NULL \|\| !devs)
153	return 0;
154	if (authctxt->kbdintctxt == NULL)
155	authctxt->kbdintctxt = kbdint_alloc(devs);
156	return auth2_challenge_start(authctxt);
157	}
158
159	/* side effect: sets authctxt->postponed if a reply was sent*/
160	static int
161	auth2_challenge_start(Authctxt *authctxt)
162	{
163	KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
164
165	debug2("auth2_challenge_start: devices %s",
166	kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
167
168	if (kbdint_next_device(kbdintctxt) == 0) {
169	kbdint_free(kbdintctxt);
170	authctxt->kbdintctxt = NULL;
171	return 0;
172	}
173	debug("auth2_challenge_start: trying authentication method '%s'",
174	kbdintctxt->device->name);
175
176	if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
177	kbdint_free(kbdintctxt);
178	authctxt->kbdintctxt = NULL;
179	return 0;
180	}
181	if (send_userauth_info_request(authctxt) == 0) {
182	kbdint_free(kbdintctxt);
183	authctxt->kbdintctxt = NULL;
184	return 0;
185	}
186	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
187	&input_userauth_info_response);
188
189	authctxt->postponed = 1;
190	return 0;
191	}
192
193	static int
194	send_userauth_info_request(Authctxt *authctxt)
195	{
196	KbdintAuthctxt *kbdintctxt;
197	char name, instr, **prompts;
198	int i;
199	u_int numprompts, *echo_on;
200
201	kbdintctxt = authctxt->kbdintctxt;
202	if (kbdintctxt->device->query(kbdintctxt->ctxt,
203	&name, &instr, &numprompts, &prompts, &echo_on))
204	return 0;
205
206	packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
207	packet_put_cstring(name);
208	packet_put_cstring(instr);
209	packet_put_cstring(""); /* language not used */
210	packet_put_int(numprompts);
211	for (i = 0; i < numprompts; i++) {
212	packet_put_cstring(prompts[i]);
213	packet_put_char(echo_on[i]);
214	}
215	packet_send();
216	packet_write_wait();
217
218	for (i = 0; i < numprompts; i++)
219	xfree(prompts[i]);
220	xfree(prompts);
221	xfree(echo_on);
222	xfree(name);
223	xfree(instr);
224	return 1;
225	}
226
227	static void
228	input_userauth_info_response(int type, int plen, void *ctxt)
229	{
230	Authctxt *authctxt = ctxt;
231	KbdintAuthctxt *kbdintctxt;
232	int i, authenticated = 0, res, len;
233	u_int nresp;
234	char *response = NULL, method;
235
236	if (authctxt == NULL)
237	fatal("input_userauth_info_response: no authctxt");
238	kbdintctxt = authctxt->kbdintctxt;
239	if (kbdintctxt == NULL \|\| kbdintctxt->ctxt == NULL)
240	fatal("input_userauth_info_response: no kbdintctxt");
241	if (kbdintctxt->device == NULL)
242	fatal("input_userauth_info_response: no device");
243
244	authctxt->postponed = 0; /* reset */
245	nresp = packet_get_int();
246	if (nresp > 0) {
247	response = xmalloc(nresp * sizeof(char*));
248	for (i = 0; i < nresp; i++)
249	response[i] = packet_get_string(NULL);
250	}
251	packet_done();
252
253	if (authctxt->valid) {
254	res = kbdintctxt->device->respond(kbdintctxt->ctxt,
255	nresp, response);
256	} else {
257	res = -1;
258	}
259
260	for (i = 0; i < nresp; i++) {
261	memset(response[i], 'r', strlen(response[i]));
262	xfree(response[i]);
263	}
264	if (response)
265	xfree(response);
266
267	switch (res) {
268	case 0:
269	/* Success! */
270	authenticated = 1;
271	break;
272	case 1:
273	/* Authentication needs further interaction */
274	authctxt->postponed = 1;
275	if (send_userauth_info_request(authctxt) == 0) {
276	authctxt->postponed = 0;
277	}
278	break;
279	default:
280	/* Failure! */
281	break;
282	}
283
284	len = strlen("keyboard-interactive") + 2 +
285	strlen(kbdintctxt->device->name);
286	method = xmalloc(len);
287	method[0] = '\0';
288	strlcat(method, "keyboard-interactive", len);
289	strlcat(method, "/", len);
290	strlcat(method, kbdintctxt->device->name, len);
291
292	if (!authctxt->postponed) {
293	/* unregister callback */
294	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
295
296	if (authenticated) {
297	kbdint_free(kbdintctxt);
298	authctxt->kbdintctxt = NULL;
299	} else {
300	/* start next device */
301	/* may set authctxt->postponed */
302	auth2_challenge_start(authctxt);
303	}
304	}
305	userauth_finish(authctxt, authenticated, method);
306	xfree(method);
307	}