xref: /openbmc/linux/drivers/nfc/st21nfca/se.c (revision 287dcc2b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
4  */
5 
6 #include <net/nfc/hci.h>
7 
8 #include "st21nfca.h"
9 
10 #define ST21NFCA_EVT_UICC_ACTIVATE		0x10
11 #define ST21NFCA_EVT_UICC_DEACTIVATE		0x13
12 #define ST21NFCA_EVT_SE_HARD_RESET		0x20
13 #define ST21NFCA_EVT_SE_SOFT_RESET		0x11
14 #define ST21NFCA_EVT_SE_END_OF_APDU_TRANSFER	0x21
15 #define ST21NFCA_EVT_SE_ACTIVATE		0x22
16 #define ST21NFCA_EVT_SE_DEACTIVATE		0x23
17 
18 #define ST21NFCA_EVT_TRANSMIT_DATA		0x10
19 #define ST21NFCA_EVT_WTX_REQUEST		0x11
20 
21 #define ST21NFCA_EVT_CONNECTIVITY		0x10
22 #define ST21NFCA_EVT_TRANSACTION		0x12
23 
24 #define ST21NFCA_SE_TO_HOT_PLUG			1000
25 /* Connectivity pipe only */
26 #define ST21NFCA_SE_COUNT_PIPE_UICC		0x01
27 /* Connectivity + APDU Reader pipe */
28 #define ST21NFCA_SE_COUNT_PIPE_EMBEDDED	0x02
29 
30 #define ST21NFCA_SE_MODE_OFF			0x00
31 #define ST21NFCA_SE_MODE_ON				0x01
32 
33 #define ST21NFCA_PARAM_ATR				0x01
34 #define ST21NFCA_ATR_DEFAULT_BWI		0x04
35 
36 /*
37  * WT = 2^BWI/10[s], convert into msecs and add a secure
38  * room by increasing by 2 this timeout
39  */
40 #define ST21NFCA_BWI_TO_TIMEOUT(x)		((1 << x) * 200)
41 #define ST21NFCA_ATR_GET_Y_FROM_TD(x)	(x >> 4)
42 
43 /* If TA is present bit 0 is set */
44 #define ST21NFCA_ATR_TA_PRESENT(x) (x & 0x01)
45 /* If TB is present bit 1 is set */
46 #define ST21NFCA_ATR_TB_PRESENT(x) (x & 0x02)
47 
48 static u8 st21nfca_se_get_bwi(struct nfc_hci_dev *hdev)
49 {
50 	int i;
51 	u8 td;
52 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
53 
54 	/* Bits 8 to 5 of the first TB for T=1 encode BWI from zero to nine */
55 	for (i = 1; i < ST21NFCA_ESE_MAX_LENGTH; i++) {
56 		td = ST21NFCA_ATR_GET_Y_FROM_TD(info->se_info.atr[i]);
57 		if (ST21NFCA_ATR_TA_PRESENT(td))
58 			i++;
59 		if (ST21NFCA_ATR_TB_PRESENT(td)) {
60 			i++;
61 			return info->se_info.atr[i] >> 4;
62 		}
63 	}
64 	return ST21NFCA_ATR_DEFAULT_BWI;
65 }
66 
67 static void st21nfca_se_get_atr(struct nfc_hci_dev *hdev)
68 {
69 	int r;
70 	struct sk_buff *skb;
71 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
72 
73 	r = nfc_hci_get_param(hdev, ST21NFCA_APDU_READER_GATE,
74 			ST21NFCA_PARAM_ATR, &skb);
75 	if (r < 0)
76 		return;
77 
78 	if (skb->len <= ST21NFCA_ESE_MAX_LENGTH) {
79 		memcpy(info->se_info.atr, skb->data, skb->len);
80 		info->se_info.wt_timeout =
81 			ST21NFCA_BWI_TO_TIMEOUT(st21nfca_se_get_bwi(hdev));
82 	}
83 	kfree_skb(skb);
84 }
85 
86 static int st21nfca_hci_control_se(struct nfc_hci_dev *hdev, u32 se_idx,
87 				u8 state)
88 {
89 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
90 	int r, i;
91 	struct sk_buff *sk_host_list;
92 	u8 se_event, host_id;
93 
94 	switch (se_idx) {
95 	case NFC_HCI_UICC_HOST_ID:
96 		se_event = (state == ST21NFCA_SE_MODE_ON ?
97 					ST21NFCA_EVT_UICC_ACTIVATE :
98 					ST21NFCA_EVT_UICC_DEACTIVATE);
99 
100 		info->se_info.count_pipes = 0;
101 		info->se_info.expected_pipes = ST21NFCA_SE_COUNT_PIPE_UICC;
102 		break;
103 	case ST21NFCA_ESE_HOST_ID:
104 		se_event = (state == ST21NFCA_SE_MODE_ON ?
105 					ST21NFCA_EVT_SE_ACTIVATE :
106 					ST21NFCA_EVT_SE_DEACTIVATE);
107 
108 		info->se_info.count_pipes = 0;
109 		info->se_info.expected_pipes = ST21NFCA_SE_COUNT_PIPE_EMBEDDED;
110 		break;
111 	default:
112 		return -EINVAL;
113 	}
114 
115 	/*
116 	 * Wait for an EVT_HOT_PLUG in order to
117 	 * retrieve a relevant host list.
118 	 */
119 	reinit_completion(&info->se_info.req_completion);
120 	r = nfc_hci_send_event(hdev, ST21NFCA_DEVICE_MGNT_GATE, se_event,
121 			       NULL, 0);
122 	if (r < 0)
123 		return r;
124 
125 	mod_timer(&info->se_info.se_active_timer, jiffies +
126 		msecs_to_jiffies(ST21NFCA_SE_TO_HOT_PLUG));
127 	info->se_info.se_active = true;
128 
129 	/* Ignore return value and check in any case the host_list */
130 	wait_for_completion_interruptible(&info->se_info.req_completion);
131 
132 	r = nfc_hci_get_param(hdev, NFC_HCI_ADMIN_GATE,
133 			NFC_HCI_ADMIN_HOST_LIST,
134 			&sk_host_list);
135 	if (r < 0)
136 		return r;
137 
138 	for (i = 0; i < sk_host_list->len &&
139 		sk_host_list->data[i] != se_idx; i++)
140 		;
141 	host_id = sk_host_list->data[i];
142 	kfree_skb(sk_host_list);
143 
144 	if (state == ST21NFCA_SE_MODE_ON && host_id == se_idx)
145 		return se_idx;
146 	else if (state == ST21NFCA_SE_MODE_OFF && host_id != se_idx)
147 		return se_idx;
148 
149 	return -1;
150 }
151 
152 int st21nfca_hci_discover_se(struct nfc_hci_dev *hdev)
153 {
154 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
155 	int se_count = 0;
156 
157 	if (test_bit(ST21NFCA_FACTORY_MODE, &hdev->quirks))
158 		return 0;
159 
160 	if (info->se_status->is_uicc_present) {
161 		nfc_add_se(hdev->ndev, NFC_HCI_UICC_HOST_ID, NFC_SE_UICC);
162 		se_count++;
163 	}
164 
165 	if (info->se_status->is_ese_present) {
166 		nfc_add_se(hdev->ndev, ST21NFCA_ESE_HOST_ID, NFC_SE_EMBEDDED);
167 		se_count++;
168 	}
169 
170 	return !se_count;
171 }
172 EXPORT_SYMBOL(st21nfca_hci_discover_se);
173 
174 int st21nfca_hci_enable_se(struct nfc_hci_dev *hdev, u32 se_idx)
175 {
176 	int r;
177 
178 	/*
179 	 * According to upper layer, se_idx == NFC_SE_UICC when
180 	 * info->se_status->is_uicc_enable is true should never happen.
181 	 * Same for eSE.
182 	 */
183 	r = st21nfca_hci_control_se(hdev, se_idx, ST21NFCA_SE_MODE_ON);
184 	if (r == ST21NFCA_ESE_HOST_ID) {
185 		st21nfca_se_get_atr(hdev);
186 		r = nfc_hci_send_event(hdev, ST21NFCA_APDU_READER_GATE,
187 				ST21NFCA_EVT_SE_SOFT_RESET, NULL, 0);
188 		if (r < 0)
189 			return r;
190 	} else if (r < 0) {
191 		/*
192 		 * The activation tentative failed, the secure element
193 		 * is not connected. Remove from the list.
194 		 */
195 		nfc_remove_se(hdev->ndev, se_idx);
196 		return r;
197 	}
198 
199 	return 0;
200 }
201 EXPORT_SYMBOL(st21nfca_hci_enable_se);
202 
203 int st21nfca_hci_disable_se(struct nfc_hci_dev *hdev, u32 se_idx)
204 {
205 	int r;
206 
207 	/*
208 	 * According to upper layer, se_idx == NFC_SE_UICC when
209 	 * info->se_status->is_uicc_enable is true should never happen
210 	 * Same for eSE.
211 	 */
212 	r = st21nfca_hci_control_se(hdev, se_idx, ST21NFCA_SE_MODE_OFF);
213 	if (r < 0)
214 		return r;
215 
216 	return 0;
217 }
218 EXPORT_SYMBOL(st21nfca_hci_disable_se);
219 
220 int st21nfca_hci_se_io(struct nfc_hci_dev *hdev, u32 se_idx,
221 			u8 *apdu, size_t apdu_length,
222 			se_io_cb_t cb, void *cb_context)
223 {
224 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
225 
226 	pr_debug("se_io %x\n", se_idx);
227 
228 	switch (se_idx) {
229 	case ST21NFCA_ESE_HOST_ID:
230 		info->se_info.cb = cb;
231 		info->se_info.cb_context = cb_context;
232 		mod_timer(&info->se_info.bwi_timer, jiffies +
233 			  msecs_to_jiffies(info->se_info.wt_timeout));
234 		info->se_info.bwi_active = true;
235 		return nfc_hci_send_event(hdev, ST21NFCA_APDU_READER_GATE,
236 					ST21NFCA_EVT_TRANSMIT_DATA,
237 					apdu, apdu_length);
238 	default:
239 		/* Need to free cb_context here as at the moment we can't
240 		 * clearly indicate to the caller if the callback function
241 		 * would be called (and free it) or not. In both cases a
242 		 * negative value may be returned to the caller.
243 		 */
244 		kfree(cb_context);
245 		return -ENODEV;
246 	}
247 }
248 EXPORT_SYMBOL(st21nfca_hci_se_io);
249 
250 static void st21nfca_se_wt_work(struct work_struct *work)
251 {
252 	/*
253 	 * No answer from the secure element
254 	 * within the defined timeout.
255 	 * Let's send a reset request as recovery procedure.
256 	 * According to the situation, we first try to send a software reset
257 	 * to the secure element. If the next command is still not
258 	 * answering in time, we send to the CLF a secure element hardware
259 	 * reset request.
260 	 */
261 	/* hardware reset managed through VCC_UICC_OUT power supply */
262 	u8 param = 0x01;
263 	struct st21nfca_hci_info *info = container_of(work,
264 						struct st21nfca_hci_info,
265 						se_info.timeout_work);
266 
267 	info->se_info.bwi_active = false;
268 
269 	if (!info->se_info.xch_error) {
270 		info->se_info.xch_error = true;
271 		nfc_hci_send_event(info->hdev, ST21NFCA_APDU_READER_GATE,
272 				ST21NFCA_EVT_SE_SOFT_RESET, NULL, 0);
273 	} else {
274 		info->se_info.xch_error = false;
275 		nfc_hci_send_event(info->hdev, ST21NFCA_DEVICE_MGNT_GATE,
276 				ST21NFCA_EVT_SE_HARD_RESET, &param, 1);
277 	}
278 	info->se_info.cb(info->se_info.cb_context, NULL, 0, -ETIME);
279 }
280 
281 static void st21nfca_se_wt_timeout(struct timer_list *t)
282 {
283 	struct st21nfca_hci_info *info = from_timer(info, t, se_info.bwi_timer);
284 
285 	schedule_work(&info->se_info.timeout_work);
286 }
287 
288 static void st21nfca_se_activation_timeout(struct timer_list *t)
289 {
290 	struct st21nfca_hci_info *info = from_timer(info, t,
291 						    se_info.se_active_timer);
292 
293 	info->se_info.se_active = false;
294 
295 	complete(&info->se_info.req_completion);
296 }
297 
298 /*
299  * Returns:
300  * <= 0: driver handled the event, skb consumed
301  *    1: driver does not handle the event, please do standard processing
302  */
303 int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
304 				u8 event, struct sk_buff *skb)
305 {
306 	int r = 0;
307 	struct device *dev = &hdev->ndev->dev;
308 	struct nfc_evt_transaction *transaction;
309 	u32 aid_len;
310 	u8 params_len;
311 
312 	pr_debug("connectivity gate event: %x\n", event);
313 
314 	switch (event) {
315 	case ST21NFCA_EVT_CONNECTIVITY:
316 		r = nfc_se_connectivity(hdev->ndev, host);
317 	break;
318 	case ST21NFCA_EVT_TRANSACTION:
319 		/* According to specification etsi 102 622
320 		 * 11.2.2.4 EVT_TRANSACTION Table 52
321 		 * Description	Tag	Length
322 		 * AID		81	5 to 16
323 		 * PARAMETERS	82	0 to 255
324 		 *
325 		 * The key differences are aid storage length is variably sized
326 		 * in the packet, but fixed in nfc_evt_transaction, and that the aid_len
327 		 * is u8 in the packet, but u32 in the structure, and the tags in
328 		 * the packet are not included in nfc_evt_transaction.
329 		 *
330 		 * size in bytes: 1          1       5-16 1             1           0-255
331 		 * offset:        0          1       2    aid_len + 2   aid_len + 3 aid_len + 4
332 		 * member name:   aid_tag(M) aid_len aid  params_tag(M) params_len  params
333 		 * example:       0x81       5-16    X    0x82 0-255    X
334 		 */
335 		if (skb->len < 2 || skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG)
336 			return -EPROTO;
337 
338 		aid_len = skb->data[1];
339 
340 		if (skb->len < aid_len + 4 || aid_len > sizeof(transaction->aid))
341 			return -EPROTO;
342 
343 		params_len = skb->data[aid_len + 3];
344 
345 		/* Verify PARAMETERS tag is (82), and final check that there is enough
346 		 * space in the packet to read everything.
347 		 */
348 		if ((skb->data[aid_len + 2] != NFC_EVT_TRANSACTION_PARAMS_TAG) ||
349 		    (skb->len < aid_len + 4 + params_len))
350 			return -EPROTO;
351 
352 		transaction = devm_kzalloc(dev, sizeof(*transaction) + params_len, GFP_KERNEL);
353 		if (!transaction)
354 			return -ENOMEM;
355 
356 		transaction->aid_len = aid_len;
357 		transaction->params_len = params_len;
358 
359 		memcpy(transaction->aid, &skb->data[2], aid_len);
360 		memcpy(transaction->params, &skb->data[aid_len + 4], params_len);
361 
362 		r = nfc_se_transaction(hdev->ndev, host, transaction);
363 	break;
364 	default:
365 		nfc_err(&hdev->ndev->dev, "Unexpected event on connectivity gate\n");
366 		return 1;
367 	}
368 	kfree_skb(skb);
369 	return r;
370 }
371 EXPORT_SYMBOL(st21nfca_connectivity_event_received);
372 
373 int st21nfca_apdu_reader_event_received(struct nfc_hci_dev *hdev,
374 					u8 event, struct sk_buff *skb)
375 {
376 	int r = 0;
377 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
378 
379 	pr_debug("apdu reader gate event: %x\n", event);
380 
381 	switch (event) {
382 	case ST21NFCA_EVT_TRANSMIT_DATA:
383 		del_timer_sync(&info->se_info.bwi_timer);
384 		cancel_work_sync(&info->se_info.timeout_work);
385 		info->se_info.bwi_active = false;
386 		r = nfc_hci_send_event(hdev, ST21NFCA_DEVICE_MGNT_GATE,
387 				ST21NFCA_EVT_SE_END_OF_APDU_TRANSFER, NULL, 0);
388 		if (r < 0)
389 			goto exit;
390 
391 		info->se_info.cb(info->se_info.cb_context,
392 			skb->data, skb->len, 0);
393 		break;
394 	case ST21NFCA_EVT_WTX_REQUEST:
395 		mod_timer(&info->se_info.bwi_timer, jiffies +
396 				msecs_to_jiffies(info->se_info.wt_timeout));
397 		break;
398 	default:
399 		nfc_err(&hdev->ndev->dev, "Unexpected event on apdu reader gate\n");
400 		return 1;
401 	}
402 
403 exit:
404 	kfree_skb(skb);
405 	return r;
406 }
407 EXPORT_SYMBOL(st21nfca_apdu_reader_event_received);
408 
409 void st21nfca_se_init(struct nfc_hci_dev *hdev)
410 {
411 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
412 
413 	init_completion(&info->se_info.req_completion);
414 	INIT_WORK(&info->se_info.timeout_work, st21nfca_se_wt_work);
415 	/* initialize timers */
416 	timer_setup(&info->se_info.bwi_timer, st21nfca_se_wt_timeout, 0);
417 	info->se_info.bwi_active = false;
418 
419 	timer_setup(&info->se_info.se_active_timer,
420 		    st21nfca_se_activation_timeout, 0);
421 	info->se_info.se_active = false;
422 
423 	info->se_info.count_pipes = 0;
424 	info->se_info.expected_pipes = 0;
425 
426 	info->se_info.xch_error = false;
427 
428 	info->se_info.wt_timeout =
429 			ST21NFCA_BWI_TO_TIMEOUT(ST21NFCA_ATR_DEFAULT_BWI);
430 }
431 EXPORT_SYMBOL(st21nfca_se_init);
432 
433 void st21nfca_se_deinit(struct nfc_hci_dev *hdev)
434 {
435 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
436 
437 	if (info->se_info.bwi_active)
438 		del_timer_sync(&info->se_info.bwi_timer);
439 	if (info->se_info.se_active)
440 		del_timer_sync(&info->se_info.se_active_timer);
441 
442 	cancel_work_sync(&info->se_info.timeout_work);
443 	info->se_info.bwi_active = false;
444 	info->se_info.se_active = false;
445 }
446 EXPORT_SYMBOL(st21nfca_se_deinit);
447