summaryrefslogtreecommitdiffstats
path: root/hcid/security.c
blob: a980b5004cca1fc16bbbb27641d68ec18458b13c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
/* 
   BlueZ - Bluetooth protocol stack for Linux
   Copyright (C) 2000-2001 Qualcomm Incorporated
   
   Written 2000,2001 by Maxim Krasnyansky <maxk@qualcomm.com>
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 as
   published by the Free Software Foundation;
   
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY CLAIM,
   OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER
   RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
   USE OR PERFORMANCE OF THIS SOFTWARE.
   
   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS, COPYRIGHTS,
   TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS SOFTWARE IS DISCLAIMED.
*/
/*
 * $Id$
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <syslog.h>
#include <errno.h>
#include <time.h>
#include <fcntl.h>
#include <time.h>

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <asm/types.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/hci_lib.h>

#include <glib.h>

#include "hcid.h"
#include "lib.h"

static GIOChannel *io_chan[HCI_MAX_DEV];

/* Link Key handling */

void flush_link_keys(void)
{
	syslog(LOG_INFO, "Flushing link key database");
	truncate(hcid.key_file, 0);
}

/* This function is not reentrable */
static struct link_key *get_link_key(bdaddr_t *sba, bdaddr_t *dba)
{
	static struct link_key k;
	struct link_key *key = NULL;
	int f, r;

	f = open(hcid.key_file, O_RDONLY);
	if (f < 0) {
		if (errno != ENOENT)
			syslog(LOG_ERR, "Link key database open failed. %s(%d)",
					strerror(errno), errno);
		return NULL;
	}

	while ((r = read_n(f, &k, sizeof(k)))) {
		if (r < 0) {
			syslog(LOG_ERR, "Link key database read failed. %s(%d)",
					strerror(errno), errno);
			break;
		}

		if (!bacmp(&k.sba, sba) && !bacmp(&k.dba, dba)) {
			key = &k;
			break;
		}
	}
	
	close(f);
	return key;
}

static void link_key_request(int dev, bdaddr_t *sba, bdaddr_t *dba)
{
	struct link_key *key = get_link_key(sba, dba);

	if (key) {
		/* Link key found */
		link_key_reply_cp lr;
		memcpy(lr.link_key, key->key, 16);
		bacpy(&lr.bdaddr, dba);
		hci_send_cmd(dev, OGF_LINK_CTL, OCF_LINK_KEY_REPLY,
				LINK_KEY_REPLY_CP_SIZE, &lr);
		key->time = time(0);
	} else {
		/* Link key not found */
		hci_send_cmd(dev, OGF_LINK_CTL, OCF_LINK_KEY_NEG_REPLY, 6, dba);
	}
}

static void save_link_key(struct link_key *key)
{
	char sa[40], da[40];
	int f;

	f = open(hcid.key_file, O_WRONLY | O_CREAT | O_APPEND, 0);
	if (f < 0) {
		syslog(LOG_ERR, "Link key database open failed. %s(%d)",
				strerror(errno), errno);
		return;
	}

	if (write_n(f, key, sizeof(*key)) < 0) {
		syslog(LOG_ERR, "Link key database write failed. %s(%d)",
				strerror(errno), errno);
	}

	close(f);

	ba2str(&key->sba, sa); ba2str(&key->dba, da);
	syslog(LOG_INFO, "Saving link key %s %s", sa, da);
}

static void link_key_notify(int dev, bdaddr_t *sba, void *ptr)
{
	evt_link_key_notify *evt = ptr;
	bdaddr_t *dba = &evt->bdaddr;
	struct link_key key;
	
	memcpy(key.key, evt->link_key, 16);
	bacpy(&key.sba, sba);
	bacpy(&key.dba, dba);
	key.type = evt->key_type;
	key.time = time(0);
	
	save_link_key(&key);
}

/* PIN code handling */

int read_pin_code(void)
{
	char buf[17];
	FILE *f; 
	int len;

	if (!(f = fopen(hcid.pin_file, "r"))) {
		syslog(LOG_ERR, "Can't open PIN file %s. %s(%d)",
				hcid.pin_file, strerror(errno), errno);
		return -1;
	}

	if (fgets(buf, sizeof(buf), f)) {
		strtok(buf, "\n\r");
		len = strlen(buf); 
		memcpy(hcid.pin_code, buf, len);
		hcid.pin_len = len;
	} else {
		syslog(LOG_ERR, "Can't read PIN file %s. %s(%d)",
				hcid.pin_file, strerror(errno), errno);
		len = -1;
	}
	fclose(f);
	return len;
}

/*
  PIN helper is an external app that asks user for a PIN. It can 
  implement its own PIN  code generation policy and methods like
  PIN look up in some database, etc. 
  HCId expects following output from PIN helper:
	PIN:12345678	-	PIN code
	ERR		-	No PIN available
*/

static void call_pin_helper(int dev, struct hci_conn_info *ci)
{
	pin_code_reply_cp pr;
	char str[255], *pin, name[20];
	bdaddr_t ba;
	FILE *pipe;
	int len;
	
	/* Run PIN helper in the separate process */
	switch (fork()) {
		case 0:
			break;
		case -1:
			syslog(LOG_ERR, "Can't fork PIN helper. %s(%d)", 
					strerror(errno), errno);
		default:
			return;
	}

	if (access(hcid.pin_helper, R_OK | X_OK)) {
		syslog(LOG_ERR, "Can't exec PIN helper %s. %s(%d)",
				hcid.pin_helper, strerror(errno), errno);
		goto reject;
	}

	name[0] = 0;
	//hci_remote_name(dev, &ci->bdaddr, sizeof(name), name, 0);

	baswap(&ba, &ci->bdaddr);
	sprintf(str, "%s %s %s \'%s\'", hcid.pin_helper, 
			ci->out ? "out" : "in", 
			batostr(&ba), name);

	setenv("PATH", "/bin:/usr/bin:/usr/local/bin", 1);

	pipe = popen(str, "r");
	if (!pipe) {
		syslog(LOG_ERR, "Can't exec PIN helper. %s(%d)", strerror(errno), errno);
		goto reject;
	}	

	pin = fgets(str, sizeof(str), pipe);
	pclose(pipe);

	if (!pin || strlen(pin) < 5)
		goto reject;

	strtok(pin, "\n\r");

	if (strncmp("PIN:", pin, 4))
		goto reject;

	pin += 4;
	len  = strlen(pin);
	
	memset(&pr, 0, sizeof(pr));
	bacpy(&pr.bdaddr, &ci->bdaddr);
	memcpy(pr.pin_code, pin, len);
	pr.pin_len = len;
	hci_send_cmd(dev, OGF_LINK_CTL, OCF_PIN_CODE_REPLY,
			PIN_CODE_REPLY_CP_SIZE, &pr);
	exit(0);

reject:
	hci_send_cmd(dev, OGF_LINK_CTL, OCF_PIN_CODE_NEG_REPLY, 6, &ci->bdaddr);
	exit(0);
}

static void pin_code_request(int dev, bdaddr_t *ba)
{
	struct hci_conn_info_req *cr;
	struct hci_conn_info *ci;
	
	cr = malloc(sizeof(*cr) + sizeof(*ci));
	if (!cr)
		return;

	bacpy(&cr->bdaddr, ba);
	cr->type = ACL_LINK;
	if (ioctl(dev, HCIGETCONNINFO, (unsigned long) cr) < 0) {
		syslog(LOG_ERR, "Can't get conn info %s(%d)",
					strerror(errno), errno);
		/* Reject PIN */
		hci_send_cmd(dev, OGF_LINK_CTL, OCF_PIN_CODE_NEG_REPLY, 6, ba);

		free(cr);
		return;
	}
	ci = cr->conn_info;

	if (hcid.security == HCID_SEC_AUTO) {
		if (!ci->out) {
			/* Incomming connection */
			pin_code_reply_cp pr;
			memset(&pr, 0, sizeof(pr));
			bacpy(&pr.bdaddr, ba);
			memcpy(pr.pin_code, hcid.pin_code, hcid.pin_len);
			pr.pin_len = hcid.pin_len;
			hci_send_cmd(dev, OGF_LINK_CTL, OCF_PIN_CODE_REPLY,
				PIN_CODE_REPLY_CP_SIZE, &pr);
		} else {
			/* Outgoing connection */
		
			/* Let PIN helper handle that */ 
			call_pin_helper(dev, ci);
		}
	} else {
		/* Let PIN helper handle that */ 
		call_pin_helper(dev, ci);
	}	
	free(cr);
}

gboolean io_security_event(GIOChannel *chan, GIOCondition cond, gpointer data)
{
	char buf[HCI_MAX_EVENT_SIZE], *ptr = buf;
	struct hci_dev_info *di = (void *) data;
	int len, type, dev;
	hci_event_hdr *eh;
	GIOError err;

	if (cond & G_IO_NVAL) {
		free(data);
		return FALSE;
	}

	if (cond & (G_IO_HUP | G_IO_ERR)) {
		g_io_channel_close(chan);
		free(data);
		return FALSE;
	}
	
	if ((err = g_io_channel_read(chan, buf, sizeof(buf), &len))) {
		if (err == G_IO_ERROR_AGAIN)
			return TRUE;
		g_io_channel_close(chan);
		return FALSE;
	}

	type = *ptr++;

	if (type != HCI_EVENT_PKT)
		return TRUE;

	eh = (hci_event_hdr *) ptr;
	ptr += HCI_EVENT_HDR_SIZE;

	dev = g_io_channel_unix_get_fd(chan);

	switch (eh->evt) {
	case EVT_PIN_CODE_REQ:
		pin_code_request(dev, (bdaddr_t *) ptr);
		break;

	case EVT_LINK_KEY_REQ:
		link_key_request(dev, &di->bdaddr, (bdaddr_t *) ptr);
		break;

	case EVT_LINK_KEY_NOTIFY:
		link_key_notify(dev, &di->bdaddr, ptr);
		break;
	}
		
	return TRUE;
}

static void init_security_data(void)
{
	static int initialized = 0;

	if (initialized)
		return;
	initialized = 1;
	
	/* Set local PIN code */
	if (hcid.security == HCID_SEC_AUTO) {
		if (read_pin_code() < 0) {
			strcpy(hcid.pin_code, "bluez");
			hcid.pin_len = 5;
		}
	}
	return;
}

void start_security_manager(int hdev)
{
	GIOChannel *chan = io_chan[hdev];
	struct hci_dev_info *di;
	struct hci_filter flt;
	int dev;

	if (chan)
		return;
	
	syslog(LOG_INFO, "Starting security manager %d", hdev);

	init_security_data();

	if ((dev = hci_open_dev(hdev)) < 0) {
		syslog(LOG_ERR, "Can't open device hci%d. %s(%d)",
				hdev, strerror(errno), errno);
		return;
	}

	/* Set filter */
	hci_filter_clear(&flt);
	hci_filter_set_ptype(HCI_EVENT_PKT, &flt);
	hci_filter_set_event(EVT_PIN_CODE_REQ, &flt);
	hci_filter_set_event(EVT_LINK_KEY_REQ, &flt);
	hci_filter_set_event(EVT_LINK_KEY_NOTIFY, &flt);
	if (setsockopt(dev, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
		syslog(LOG_ERR, "Can't set filter on hci%d. %s(%d)", 
				hdev, strerror(errno), errno);
		close(dev);
		return;
	}

	di = malloc(sizeof(*di));
	if (!di) {
		syslog(LOG_ERR, "Can't allocate device info buffer. %s(%d)", 
				strerror(errno), errno);
		close(dev);
		return;
	}
	
	di->dev_id = hdev;
	if (ioctl(dev, HCIGETDEVINFO, (void *)di)) {
		syslog(LOG_ERR, "Can't get device info. %s(%d)", 
				strerror(errno), errno);
		close(dev);
		return;
	}
	
	chan = g_io_channel_unix_new(dev);
	g_io_add_watch(chan, G_IO_IN | G_IO_NVAL | G_IO_HUP | G_IO_ERR,
			io_security_event, (void *) di);

	io_chan[hdev] = chan;
}

void stop_security_manager(int hdev)
{
	GIOChannel *chan = io_chan[hdev];

	if (!chan)
		return;

	syslog(LOG_INFO, "Stoping security manager %d", hdev);

	close(g_io_channel_unix_get_fd(chan));
	io_chan[hdev] = NULL;
}