1 /******************************************************************************
2 *
3 * Copyright (C) 1999-2012 Broadcom Corporation
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19 /******************************************************************************
20 *
21 * this file contains GATT authentication handling functions
22 *
23 ******************************************************************************/
24 #include "bt_target.h"
25
26 #if BLE_INCLUDED == TRUE
27 #include <string.h>
28 #include "gki.h"
29
30 #include "gatt_int.h"
31 #include "gatt_api.h"
32 #include "btm_int.h"
33
34 /*******************************************************************************
35 **
36 ** Function gatt_sign_data
37 **
38 ** Description This function sign the data for write command.
39 **
40 ** Returns TRUE if encrypted, otherwise FALSE.
41 **
42 *******************************************************************************/
gatt_sign_data(tGATT_CLCB * p_clcb)43 static BOOLEAN gatt_sign_data (tGATT_CLCB *p_clcb)
44 {
45 tGATT_VALUE *p_attr = (tGATT_VALUE *)p_clcb->p_attr_buf;
46 UINT8 *p_data = NULL, *p;
47 UINT16 payload_size = p_clcb->p_tcb->payload_size;
48 BOOLEAN status = FALSE;
49 UINT8 *p_signature;
50
51 /* do not need to mark channel securoty activity for data signing */
52 gatt_set_sec_act(p_clcb->p_tcb, GATT_SEC_OK);
53
54 p_data = (UINT8 *)GKI_getbuf((UINT16)(p_attr->len + 3)); /* 3 = 2 byte handle + opcode */
55
56 if (p_data != NULL)
57 {
58 p = p_data;
59 UINT8_TO_STREAM(p, GATT_SIGN_CMD_WRITE);
60 UINT16_TO_STREAM(p, p_attr->handle);
61 ARRAY_TO_STREAM(p, p_attr->value, p_attr->len);
62
63 /* sign data length should be attribulte value length plus 2B handle + 1B op code */
64 if ((payload_size - GATT_AUTH_SIGN_LEN - 3) < p_attr->len)
65 p_attr->len = payload_size - GATT_AUTH_SIGN_LEN - 3;
66
67 p_signature = p_attr->value + p_attr->len;
68 if (BTM_BleDataSignature(p_clcb->p_tcb->peer_bda,
69 p_data,
70 (UINT16)(p_attr->len + 3), /* 3 = 2 byte handle + opcode */
71 p_signature))
72 {
73 p_attr->len += BTM_BLE_AUTH_SIGN_LEN;
74 gatt_set_ch_state(p_clcb->p_tcb, GATT_CH_OPEN);
75 gatt_act_write(p_clcb, GATT_SEC_SIGN_DATA);
76 }
77 else
78 {
79 gatt_end_operation(p_clcb, GATT_INTERNAL_ERROR, NULL);
80 }
81
82 GKI_freebuf(p_data);
83 }
84
85 return status;
86 }
87
88 /*******************************************************************************
89 **
90 ** Function gatt_verify_signature
91 **
92 ** Description This function start to verify the sign data when receiving
93 ** the data from peer device.
94 **
95 ** Returns
96 **
97 *******************************************************************************/
gatt_verify_signature(tGATT_TCB * p_tcb,BT_HDR * p_buf)98 void gatt_verify_signature(tGATT_TCB *p_tcb, BT_HDR *p_buf)
99 {
100 UINT16 cmd_len;
101 UINT8 op_code;
102 UINT8 *p, *p_orig = (UINT8 *)(p_buf + 1) + p_buf->offset;
103 UINT32 counter;
104
105 cmd_len = p_buf->len - GATT_AUTH_SIGN_LEN + 4;
106 p = p_orig + cmd_len - 4;
107 STREAM_TO_UINT32(counter, p);
108
109 if (BTM_BleVerifySignature(p_tcb->peer_bda, p_orig, cmd_len, counter, p))
110 {
111 STREAM_TO_UINT8(op_code, p_orig);
112 gatt_server_handle_client_req (p_tcb, op_code, (UINT16)(p_buf->len - 1), p_orig);
113 }
114 else
115 {
116 /* if this is a bad signature, assume from attacker, ignore it */
117 GATT_TRACE_ERROR0("Signature Verification Failed");
118 gatt_disconnect(p_tcb->peer_bda);
119 }
120
121 return;
122 }
123 /*******************************************************************************
124 **
125 ** Function gatt_sec_check_complete
126 **
127 ** Description security check complete and proceed to data sending action.
128 **
129 ** Returns void.
130 **
131 *******************************************************************************/
gatt_sec_check_complete(BOOLEAN sec_check_ok,tGATT_CLCB * p_clcb,UINT8 sec_act)132 void gatt_sec_check_complete(BOOLEAN sec_check_ok, tGATT_CLCB *p_clcb, UINT8 sec_act)
133 {
134 if (GKI_queue_is_empty(&p_clcb->p_tcb->pending_enc_clcb))
135 gatt_set_sec_act(p_clcb->p_tcb, GATT_SEC_NONE);
136
137 if (!sec_check_ok)
138 {
139 gatt_end_operation(p_clcb, GATT_AUTH_FAIL, NULL);
140 }
141 else if (p_clcb->operation == GATTC_OPTYPE_WRITE)
142 {
143 gatt_act_write(p_clcb, sec_act);
144 }
145 else if (p_clcb->operation == GATTC_OPTYPE_READ)
146 {
147 gatt_act_read(p_clcb, p_clcb->counter);
148 }
149 }
150 /*******************************************************************************
151 **
152 ** Function gatt_enc_cmpl_cback
153 **
154 ** Description link encryption complete callback.
155 **
156 ** Returns
157 **
158 *******************************************************************************/
gatt_enc_cmpl_cback(BD_ADDR bd_addr,void * p_ref_data,tBTM_STATUS result)159 void gatt_enc_cmpl_cback(BD_ADDR bd_addr, void *p_ref_data, tBTM_STATUS result)
160 {
161 tGATT_TCB *p_tcb;
162 UINT8 sec_flag;
163 BOOLEAN status = FALSE;
164 tGATT_PENDING_ENC_CLCB *p_buf;
165 UINT16 count;
166
167 GATT_TRACE_DEBUG0("gatt_enc_cmpl_cback");
168 if ((p_tcb = gatt_find_tcb_by_addr(bd_addr)) != NULL)
169 {
170 if (gatt_get_sec_act(p_tcb) == GATT_SEC_ENC_PENDING)
171 return;
172
173 if ((p_buf = (tGATT_PENDING_ENC_CLCB *)GKI_dequeue (&p_tcb->pending_enc_clcb)) != NULL)
174 {
175 if (result == BTM_SUCCESS)
176 {
177 if (gatt_get_sec_act(p_tcb) == GATT_SEC_ENCRYPT_MITM )
178 {
179 BTM_GetSecurityFlags(bd_addr, &sec_flag);
180 if (sec_flag & sec_flag & BTM_SEC_FLAG_LKEY_AUTHED)
181 {
182 status = TRUE;
183 }
184 }
185 else
186 {
187 status = TRUE;
188 }
189 }
190 gatt_sec_check_complete(status , p_buf->p_clcb, p_tcb->sec_act);
191 GKI_freebuf(p_buf);
192 /* start all other pending operation in queue */
193 count = p_tcb->pending_enc_clcb.count;
194 for (; count > 0; count --)
195 {
196 if ((p_buf = (tGATT_PENDING_ENC_CLCB *)GKI_dequeue (&p_tcb->pending_enc_clcb)) != NULL)
197 {
198 gatt_security_check_start(p_buf->p_clcb);
199 GKI_freebuf(p_buf);
200 }
201 else
202 break;
203 }
204 }
205 else
206 {
207 GATT_TRACE_ERROR0("Unknown operation encryption completed");
208 }
209 }
210 else
211 {
212 GATT_TRACE_ERROR0("enc callback for unknown bd_addr");
213 }
214 }
215
216 /*******************************************************************************
217 **
218 ** Function gatt_notify_enc_cmpl
219 **
220 ** Description link encryption complete notification for all encryption process
221 ** initiated outside GATT.
222 **
223 ** Returns
224 **
225 *******************************************************************************/
gatt_notify_enc_cmpl(BD_ADDR bd_addr)226 void gatt_notify_enc_cmpl(BD_ADDR bd_addr)
227 {
228 tGATT_TCB *p_tcb;
229 tGATT_PENDING_ENC_CLCB *p_buf;
230 UINT16 count;
231
232 if ((p_tcb = gatt_find_tcb_by_addr(bd_addr)) != NULL)
233 {
234 if (gatt_get_sec_act(p_tcb) == GATT_SEC_ENC_PENDING)
235 {
236 gatt_set_sec_act(p_tcb, GATT_SEC_NONE);
237
238 count = p_tcb->pending_enc_clcb.count;
239
240 for (; count > 0; count --)
241 {
242 if ((p_buf = (tGATT_PENDING_ENC_CLCB *)GKI_dequeue (&p_tcb->pending_enc_clcb)) != NULL)
243 {
244 gatt_security_check_start(p_buf->p_clcb);
245 GKI_freebuf(p_buf);
246 }
247 else
248 break;
249 }
250 }
251 }
252 else
253 {
254 GATT_TRACE_DEBUG0("notify GATT for encryption completion of unknown device");
255 }
256 return;
257 }
258 /*******************************************************************************
259 **
260 ** Function gatt_set_sec_act
261 **
262 ** Description This function set the sec_act in clcb
263 **
264 ** Returns none
265 **
266 *******************************************************************************/
gatt_set_sec_act(tGATT_TCB * p_tcb,tGATT_SEC_ACTION sec_act)267 void gatt_set_sec_act(tGATT_TCB *p_tcb, tGATT_SEC_ACTION sec_act)
268 {
269 if (p_tcb)
270 {
271 p_tcb->sec_act = sec_act;
272 }
273 }
274 /*******************************************************************************
275 **
276 ** Function gatt_get_sec_act
277 **
278 ** Description This function get the sec_act in clcb
279 **
280 ** Returns none
281 **
282 *******************************************************************************/
gatt_get_sec_act(tGATT_TCB * p_tcb)283 tGATT_SEC_ACTION gatt_get_sec_act(tGATT_TCB *p_tcb)
284 {
285 tGATT_SEC_ACTION sec_act = GATT_SEC_NONE;
286 if (p_tcb)
287 {
288 sec_act = p_tcb->sec_act;
289 }
290 return sec_act;
291 }
292 /*******************************************************************************
293 **
294 ** Function gatt_determine_sec_act
295 **
296 ** Description This routine determine the security action based on auth_request and
297 ** current link status
298 **
299 ** Returns tGATT_SEC_ACTION security action
300 **
301 *******************************************************************************/
gatt_determine_sec_act(tGATT_CLCB * p_clcb)302 tGATT_SEC_ACTION gatt_determine_sec_act(tGATT_CLCB *p_clcb )
303 {
304 tGATT_SEC_ACTION act = GATT_SEC_OK;
305 UINT8 sec_flag;
306 tGATT_TCB *p_tcb = p_clcb->p_tcb;
307 tGATT_AUTH_REQ auth_req = p_clcb->auth_req;
308
309 BOOLEAN is_link_encrypted= FALSE;
310 BOOLEAN is_le_link=FALSE;
311 BOOLEAN is_link_key_known=FALSE;
312 BOOLEAN is_key_mitm=FALSE;
313 UINT8 key_type;
314 tBTM_BLE_SEC_REQ_ACT sec_act = BTM_LE_SEC_NONE;
315
316 if (auth_req == GATT_AUTH_REQ_NONE )
317 return act;
318
319 is_le_link = btm_ble_check_link_type(p_tcb->peer_bda);
320 BTM_GetSecurityFlags(p_tcb->peer_bda, &sec_flag);
321 btm_ble_link_sec_check(p_tcb->peer_bda, auth_req, &sec_act);
322
323 /* if a encryption is pending, need to wait */
324 if (sec_act == BTM_BLE_SEC_REQ_ACT_DISCARD &&
325 auth_req != GATT_AUTH_REQ_NONE)
326 return GATT_SEC_ENC_PENDING;
327
328 if (sec_flag & BTM_SEC_FLAG_ENCRYPTED)
329 {
330 is_link_encrypted = TRUE;
331 is_link_key_known = TRUE;
332
333 if (sec_flag & BTM_SEC_FLAG_LKEY_AUTHED)
334 {
335 is_key_mitm = TRUE;
336 }
337
338 }
339 else if (sec_flag & BTM_SEC_FLAG_LKEY_KNOWN)
340 {
341 is_link_key_known = TRUE;
342 if (sec_flag & BTM_SEC_FLAG_LKEY_AUTHED)
343 {
344 is_key_mitm = TRUE;
345 }
346 }
347
348 /* first check link key upgrade required or not */
349 switch (auth_req)
350 {
351 case GATT_AUTH_REQ_MITM:
352 case GATT_AUTH_REQ_SIGNED_MITM:
353 if (!is_key_mitm)
354 act = GATT_SEC_ENCRYPT_MITM;
355 break;
356
357 case GATT_AUTH_REQ_NO_MITM:
358 case GATT_AUTH_REQ_SIGNED_NO_MITM:
359 if (!is_link_key_known)
360 act = GATT_SEC_ENCRYPT_NO_MITM;
361 break;
362 default:
363 break;
364 }
365
366 /* now check link needs to be encrypted or not if the link key upgrade is not required */
367 if (act == GATT_SEC_OK)
368 {
369 if (is_le_link &&
370 (p_clcb->operation == GATTC_OPTYPE_WRITE) &&
371 (p_clcb->op_subtype == GATT_WRITE_NO_RSP))
372 {
373 /* this is a write command request
374 check data signing required or not */
375 if (!is_link_encrypted)
376 {
377 btm_ble_get_enc_key_type(p_tcb->peer_bda, &key_type);
378
379 if ( (key_type & BTM_LE_KEY_LCSRK) &&
380 ((auth_req == GATT_AUTH_REQ_SIGNED_NO_MITM) ||
381 (auth_req == GATT_AUTH_REQ_SIGNED_MITM)))
382 {
383 act = GATT_SEC_SIGN_DATA;
384 }
385 else
386 {
387 act = GATT_SEC_ENCRYPT;
388 }
389 }
390 }
391 else
392 {
393 if (!is_link_encrypted)
394 {
395 act = GATT_SEC_ENCRYPT;
396 }
397 }
398
399 }
400
401 return act ;
402
403 }
404
405
406
407 /*******************************************************************************
408 **
409 ** Function gatt_get_link_encrypt_status
410 **
411 ** Description This routine get the encryption status of the specified link
412 **
413 **
414 ** Returns tGATT_STATUS link encryption status
415 **
416 *******************************************************************************/
gatt_get_link_encrypt_status(tGATT_TCB * p_tcb)417 tGATT_STATUS gatt_get_link_encrypt_status(tGATT_TCB *p_tcb)
418 {
419 tGATT_STATUS encrypt_status = GATT_NOT_ENCRYPTED;
420 UINT8 sec_flag=0;
421
422 BTM_GetSecurityFlags(p_tcb->peer_bda, &sec_flag);
423
424 if ((sec_flag & BTM_SEC_FLAG_ENCRYPTED) && (sec_flag & BTM_SEC_FLAG_LKEY_KNOWN))
425 {
426 encrypt_status = GATT_ENCRYPED_NO_MITM;
427 if (sec_flag & BTM_SEC_FLAG_LKEY_AUTHED)
428 encrypt_status = GATT_ENCRYPED_MITM;
429 }
430
431 GATT_TRACE_DEBUG1("gatt_get_link_encrypt_status status=0x%x",encrypt_status);
432 return encrypt_status ;
433 }
434
435
436 /*******************************************************************************
437 **
438 ** Function gatt_convert_sec_action
439 **
440 ** Description Convert GATT security action enum into equivalent BTM BLE security action enum
441 **
442 ** Returns BOOLEAN TRUE - conversation is successful
443 **
444 *******************************************************************************/
gatt_convert_sec_action(tGATT_SEC_ACTION gatt_sec_act,tBTM_BLE_SEC_ACT * p_btm_sec_act)445 static BOOLEAN gatt_convert_sec_action(tGATT_SEC_ACTION gatt_sec_act, tBTM_BLE_SEC_ACT *p_btm_sec_act )
446 {
447 BOOLEAN status = TRUE;
448 switch (gatt_sec_act)
449 {
450 case GATT_SEC_ENCRYPT:
451 *p_btm_sec_act = BTM_BLE_SEC_ENCRYPT;
452 break;
453 case GATT_SEC_ENCRYPT_NO_MITM:
454 *p_btm_sec_act = BTM_BLE_SEC_ENCRYPT_NO_MITM;
455 break;
456 case GATT_SEC_ENCRYPT_MITM:
457 *p_btm_sec_act = BTM_BLE_SEC_ENCRYPT_MITM;
458 break;
459 default:
460 status = FALSE;
461 break;
462 }
463
464 return status;
465 }
466 /*******************************************************************************
467 **
468 ** Function gatt_check_enc_req
469 **
470 ** Description check link security.
471 **
472 ** Returns TRUE if encrypted, otherwise FALSE.
473 **
474 *******************************************************************************/
gatt_security_check_start(tGATT_CLCB * p_clcb)475 BOOLEAN gatt_security_check_start(tGATT_CLCB *p_clcb)
476 {
477 tGATT_TCB *p_tcb = p_clcb->p_tcb;
478 tGATT_SEC_ACTION gatt_sec_act;
479 tBTM_BLE_SEC_ACT btm_ble_sec_act;
480 BOOLEAN status = TRUE;
481 tBTM_STATUS btm_status;
482 tGATT_SEC_ACTION sec_act_old = gatt_get_sec_act(p_tcb);
483
484 gatt_sec_act = gatt_determine_sec_act(p_clcb);
485
486 if (sec_act_old == GATT_SEC_NONE)
487 gatt_set_sec_act(p_tcb, gatt_sec_act);
488
489 switch (gatt_sec_act )
490 {
491 case GATT_SEC_SIGN_DATA:
492 GATT_TRACE_DEBUG0("gatt_security_check_start: Do data signing");
493 gatt_sign_data(p_clcb);
494 break;
495 case GATT_SEC_ENCRYPT:
496 case GATT_SEC_ENCRYPT_NO_MITM:
497 case GATT_SEC_ENCRYPT_MITM:
498 if (sec_act_old < GATT_SEC_ENCRYPT)
499 {
500 GATT_TRACE_DEBUG0("gatt_security_check_start: Encrypt now or key upgreade first");
501 gatt_convert_sec_action(gatt_sec_act, &btm_ble_sec_act);
502 btm_status = BTM_SetEncryption(p_tcb->peer_bda, gatt_enc_cmpl_cback, &btm_ble_sec_act);
503 if ( (btm_status != BTM_SUCCESS) && (btm_status != BTM_CMD_STARTED))
504 {
505 GATT_TRACE_ERROR1("gatt_security_check_start BTM_SetEncryption failed btm_status=%d", btm_status);
506 status = FALSE;
507 }
508 }
509 if (status)
510 gatt_add_pending_enc_channel_clcb (p_tcb, p_clcb);
511 break;
512 case GATT_SEC_ENC_PENDING:
513 gatt_add_pending_enc_channel_clcb (p_tcb, p_clcb);
514 /* wait for link encrypotion to finish */
515 break;
516 default:
517 gatt_sec_check_complete(TRUE, p_clcb, gatt_sec_act);
518 break;
519 }
520
521 if (status == FALSE)
522 {
523 gatt_set_sec_act(p_tcb, GATT_SEC_NONE);
524 gatt_set_ch_state(p_tcb, GATT_CH_OPEN);
525 }
526
527 return status;
528 }
529
530
531 #endif /* BLE_INCLUDED */
532