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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Wireless USB Host Controller
4 * Security support: encryption enablement, etc
5 *
6 * Copyright (C) 2006 Intel Corporation
7 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
8 *
9 * FIXME: docs
10 */
11#include <linux/types.h>
12#include <linux/slab.h>
13#include <linux/usb/ch9.h>
14#include <linux/random.h>
15#include <linux/export.h>
16#include "wusbhc.h"
17#include <asm/unaligned.h>
18
19static void wusbhc_gtk_rekey_work(struct work_struct *work);
20
21int wusbhc_sec_create(struct wusbhc *wusbhc)
22{
23 /*
24 * WQ is singlethread because we need to serialize rekey operations.
25 * Use a separate workqueue for security operations instead of the
26 * wusbd workqueue because security operations may need to communicate
27 * directly with downstream wireless devices using synchronous URBs.
28 * If a device is not responding, this could block other host
29 * controller operations.
30 */
31 wusbhc->wq_security = create_singlethread_workqueue("wusbd_security");
32 if (wusbhc->wq_security == NULL) {
33 pr_err("WUSB-core: Cannot create wusbd_security workqueue\n");
34 return -ENOMEM;
35 }
36
37 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) +
38 sizeof(wusbhc->gtk.data);
39 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
40 wusbhc->gtk.descr.bReserved = 0;
41 wusbhc->gtk_index = 0;
42
43 INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work);
44
45 return 0;
46}
47
48
49/* Called when the HC is destroyed */
50void wusbhc_sec_destroy(struct wusbhc *wusbhc)
51{
52 destroy_workqueue(wusbhc->wq_security);
53}
54
55
56/**
57 * wusbhc_next_tkid - generate a new, currently unused, TKID
58 * @wusbhc: the WUSB host controller
59 * @wusb_dev: the device whose PTK the TKID is for
60 * (or NULL for a TKID for a GTK)
61 *
62 * The generated TKID consists of two parts: the device's authenticated
63 * address (or 0 or a GTK); and an incrementing number. This ensures
64 * that TKIDs cannot be shared between devices and by the time the
65 * incrementing number wraps around the older TKIDs will no longer be
66 * in use (a maximum of two keys may be active at any one time).
67 */
68static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
69{
70 u32 *tkid;
71 u32 addr;
72
73 if (wusb_dev == NULL) {
74 tkid = &wusbhc->gtk_tkid;
75 addr = 0;
76 } else {
77 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
78 addr = wusb_dev->addr & 0x7f;
79 }
80
81 *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
82
83 return *tkid;
84}
85
86static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
87{
88 const size_t key_size = sizeof(wusbhc->gtk.data);
89 u32 tkid;
90
91 tkid = wusbhc_next_tkid(wusbhc, NULL);
92
93 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff;
94 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff;
95 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
96
97 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
98}
99
100/**
101 * wusbhc_sec_start - start the security management process
102 * @wusbhc: the WUSB host controller
103 *
104 * Generate and set an initial GTK on the host controller.
105 *
106 * Called when the HC is started.
107 */
108int wusbhc_sec_start(struct wusbhc *wusbhc)
109{
110 const size_t key_size = sizeof(wusbhc->gtk.data);
111 int result;
112
113 wusbhc_generate_gtk(wusbhc);
114
115 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
116 &wusbhc->gtk.descr.bKeyData, key_size);
117 if (result < 0)
118 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
119 result);
120
121 return result;
122}
123
124/**
125 * wusbhc_sec_stop - stop the security management process
126 * @wusbhc: the WUSB host controller
127 *
128 * Wait for any pending GTK rekeys to stop.
129 */
130void wusbhc_sec_stop(struct wusbhc *wusbhc)
131{
132 cancel_work_sync(&wusbhc->gtk_rekey_work);
133}
134
135
136/** @returns encryption type name */
137const char *wusb_et_name(u8 x)
138{
139 switch (x) {
140 case USB_ENC_TYPE_UNSECURE: return "unsecure";
141 case USB_ENC_TYPE_WIRED: return "wired";
142 case USB_ENC_TYPE_CCM_1: return "CCM-1";
143 case USB_ENC_TYPE_RSA_1: return "RSA-1";
144 default: return "unknown";
145 }
146}
147EXPORT_SYMBOL_GPL(wusb_et_name);
148
149/*
150 * Set the device encryption method
151 *
152 * We tell the device which encryption method to use; we do this when
153 * setting up the device's security.
154 */
155static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
156{
157 int result;
158 struct device *dev = &usb_dev->dev;
159 struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
160
161 if (value) {
162 value = wusb_dev->ccm1_etd.bEncryptionValue;
163 } else {
164 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
165 value = 0;
166 }
167 /* Set device's */
168 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
169 USB_REQ_SET_ENCRYPTION,
170 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
171 value, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
172 if (result < 0)
173 dev_err(dev, "Can't set device's WUSB encryption to "
174 "%s (value %d): %d\n",
175 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
176 wusb_dev->ccm1_etd.bEncryptionValue, result);
177 return result;
178}
179
180/*
181 * Set the GTK to be used by a device.
182 *
183 * The device must be authenticated.
184 */
185static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
186{
187 struct usb_device *usb_dev = wusb_dev->usb_dev;
188 u8 key_index = wusb_key_index(wusbhc->gtk_index,
189 WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST);
190
191 return usb_control_msg(
192 usb_dev, usb_sndctrlpipe(usb_dev, 0),
193 USB_REQ_SET_DESCRIPTOR,
194 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
195 USB_DT_KEY << 8 | key_index, 0,
196 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
197 USB_CTRL_SET_TIMEOUT);
198}
199
200
201/* FIXME: prototype for adding security */
202int wusb_dev_sec_add(struct wusbhc *wusbhc,
203 struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
204{
205 int result, bytes, secd_size;
206 struct device *dev = &usb_dev->dev;
207 struct usb_security_descriptor *secd, *new_secd;
208 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
209 const void *itr, *top;
210 char buf[64];
211
212 secd = kmalloc(sizeof(*secd), GFP_KERNEL);
213 if (secd == NULL) {
214 result = -ENOMEM;
215 goto out;
216 }
217
218 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
219 0, secd, sizeof(*secd));
220 if (result < sizeof(*secd)) {
221 dev_err(dev, "Can't read security descriptor or "
222 "not enough data: %d\n", result);
223 goto out;
224 }
225 secd_size = le16_to_cpu(secd->wTotalLength);
226 new_secd = krealloc(secd, secd_size, GFP_KERNEL);
227 if (new_secd == NULL) {
228 dev_err(dev,
229 "Can't allocate space for security descriptors\n");
230 result = -ENOMEM;
231 goto out;
232 }
233 secd = new_secd;
234 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
235 0, secd, secd_size);
236 if (result < secd_size) {
237 dev_err(dev, "Can't read security descriptor or "
238 "not enough data: %d\n", result);
239 goto out;
240 }
241 bytes = 0;
242 itr = &secd[1];
243 top = (void *)secd + result;
244 while (itr < top) {
245 etd = itr;
246 if (top - itr < sizeof(*etd)) {
247 dev_err(dev, "BUG: bad device security descriptor; "
248 "not enough data (%zu vs %zu bytes left)\n",
249 top - itr, sizeof(*etd));
250 break;
251 }
252 if (etd->bLength < sizeof(*etd)) {
253 dev_err(dev, "BUG: bad device encryption descriptor; "
254 "descriptor is too short "
255 "(%u vs %zu needed)\n",
256 etd->bLength, sizeof(*etd));
257 break;
258 }
259 itr += etd->bLength;
260 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
261 "%s (0x%02x/%02x) ",
262 wusb_et_name(etd->bEncryptionType),
263 etd->bEncryptionValue, etd->bAuthKeyIndex);
264 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
265 ccm1_etd = etd;
266 }
267 /* This code only supports CCM1 as of now. */
268 /* FIXME: user has to choose which sec mode to use?
269 * In theory we want CCM */
270 if (ccm1_etd == NULL) {
271 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
272 "can't use!\n");
273 result = -EINVAL;
274 goto out;
275 }
276 wusb_dev->ccm1_etd = *ccm1_etd;
277 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
278 buf, wusb_et_name(ccm1_etd->bEncryptionType),
279 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
280 result = 0;
281out:
282 kfree(secd);
283 return result;
284}
285
286void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
287{
288 /* Nothing so far */
289}
290
291/**
292 * Update the address of an unauthenticated WUSB device
293 *
294 * Once we have successfully authenticated, we take it to addr0 state
295 * and then to a normal address.
296 *
297 * Before the device's address (as known by it) was usb_dev->devnum |
298 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
299 */
300int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
301{
302 int result = -ENOMEM;
303 struct usb_device *usb_dev = wusb_dev->usb_dev;
304 struct device *dev = &usb_dev->dev;
305 u8 new_address = wusb_dev->addr & 0x7F;
306
307 /* Set address 0 */
308 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
309 USB_REQ_SET_ADDRESS,
310 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
311 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
312 if (result < 0) {
313 dev_err(dev, "auth failed: can't set address 0: %d\n",
314 result);
315 goto error_addr0;
316 }
317 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
318 if (result < 0)
319 goto error_addr0;
320 usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
321 usb_ep0_reinit(usb_dev);
322
323 /* Set new (authenticated) address. */
324 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
325 USB_REQ_SET_ADDRESS,
326 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
327 new_address, 0, NULL, 0,
328 USB_CTRL_SET_TIMEOUT);
329 if (result < 0) {
330 dev_err(dev, "auth failed: can't set address %u: %d\n",
331 new_address, result);
332 goto error_addr;
333 }
334 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
335 if (result < 0)
336 goto error_addr;
337 usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
338 usb_ep0_reinit(usb_dev);
339 usb_dev->authenticated = 1;
340error_addr:
341error_addr0:
342 return result;
343}
344
345/*
346 *
347 *
348 */
349/* FIXME: split and cleanup */
350int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
351 struct wusb_ckhdid *ck)
352{
353 int result = -ENOMEM;
354 struct usb_device *usb_dev = wusb_dev->usb_dev;
355 struct device *dev = &usb_dev->dev;
356 u32 tkid;
357 struct usb_handshake *hs;
358 struct aes_ccm_nonce ccm_n;
359 u8 mic[8];
360 struct wusb_keydvt_in keydvt_in;
361 struct wusb_keydvt_out keydvt_out;
362
363 hs = kcalloc(3, sizeof(hs[0]), GFP_KERNEL);
364 if (!hs)
365 goto error_kzalloc;
366
367 /* We need to turn encryption before beginning the 4way
368 * hshake (WUSB1.0[.3.2.2]) */
369 result = wusb_dev_set_encryption(usb_dev, 1);
370 if (result < 0)
371 goto error_dev_set_encryption;
372
373 tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
374
375 hs[0].bMessageNumber = 1;
376 hs[0].bStatus = 0;
377 put_unaligned_le32(tkid, hs[0].tTKID);
378 hs[0].bReserved = 0;
379 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
380 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
381 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */
382
383 result = usb_control_msg(
384 usb_dev, usb_sndctrlpipe(usb_dev, 0),
385 USB_REQ_SET_HANDSHAKE,
386 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
387 1, 0, &hs[0], sizeof(hs[0]), USB_CTRL_SET_TIMEOUT);
388 if (result < 0) {
389 dev_err(dev, "Handshake1: request failed: %d\n", result);
390 goto error_hs1;
391 }
392
393 /* Handshake 2, from the device -- need to verify fields */
394 result = usb_control_msg(
395 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
396 USB_REQ_GET_HANDSHAKE,
397 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
398 2, 0, &hs[1], sizeof(hs[1]), USB_CTRL_GET_TIMEOUT);
399 if (result < 0) {
400 dev_err(dev, "Handshake2: request failed: %d\n", result);
401 goto error_hs2;
402 }
403
404 result = -EINVAL;
405 if (hs[1].bMessageNumber != 2) {
406 dev_err(dev, "Handshake2 failed: bad message number %u\n",
407 hs[1].bMessageNumber);
408 goto error_hs2;
409 }
410 if (hs[1].bStatus != 0) {
411 dev_err(dev, "Handshake2 failed: bad status %u\n",
412 hs[1].bStatus);
413 goto error_hs2;
414 }
415 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
416 dev_err(dev, "Handshake2 failed: TKID mismatch "
417 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
418 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
419 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
420 goto error_hs2;
421 }
422 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
423 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
424 goto error_hs2;
425 }
426
427 /* Setup the CCM nonce */
428 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */
429 put_unaligned_le32(tkid, ccm_n.tkid);
430 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
431 ccm_n.dest_addr.data[0] = wusb_dev->addr;
432 ccm_n.dest_addr.data[1] = 0;
433
434 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
435 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
436 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
437 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
438 if (result < 0) {
439 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
440 result);
441 goto error_hs2;
442 }
443
444 /* Compute MIC and verify it */
445 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
446 if (result < 0) {
447 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
448 result);
449 goto error_hs2;
450 }
451
452 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
453 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
454 goto error_hs2;
455 }
456
457 /* Send Handshake3 */
458 hs[2].bMessageNumber = 3;
459 hs[2].bStatus = 0;
460 put_unaligned_le32(tkid, hs[2].tTKID);
461 hs[2].bReserved = 0;
462 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
463 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
464 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
465 if (result < 0) {
466 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
467 result);
468 goto error_hs2;
469 }
470
471 result = usb_control_msg(
472 usb_dev, usb_sndctrlpipe(usb_dev, 0),
473 USB_REQ_SET_HANDSHAKE,
474 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
475 3, 0, &hs[2], sizeof(hs[2]), USB_CTRL_SET_TIMEOUT);
476 if (result < 0) {
477 dev_err(dev, "Handshake3: request failed: %d\n", result);
478 goto error_hs3;
479 }
480
481 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
482 keydvt_out.ptk, sizeof(keydvt_out.ptk));
483 if (result < 0)
484 goto error_wusbhc_set_ptk;
485
486 result = wusb_dev_set_gtk(wusbhc, wusb_dev);
487 if (result < 0) {
488 dev_err(dev, "Set GTK for device: request failed: %d\n",
489 result);
490 goto error_wusbhc_set_gtk;
491 }
492
493 /* Update the device's address from unauth to auth */
494 if (usb_dev->authenticated == 0) {
495 result = wusb_dev_update_address(wusbhc, wusb_dev);
496 if (result < 0)
497 goto error_dev_update_address;
498 }
499 result = 0;
500 dev_info(dev, "device authenticated\n");
501
502error_dev_update_address:
503error_wusbhc_set_gtk:
504error_wusbhc_set_ptk:
505error_hs3:
506error_hs2:
507error_hs1:
508 memset(hs, 0, 3*sizeof(hs[0]));
509 memzero_explicit(&keydvt_out, sizeof(keydvt_out));
510 memzero_explicit(&keydvt_in, sizeof(keydvt_in));
511 memzero_explicit(&ccm_n, sizeof(ccm_n));
512 memzero_explicit(mic, sizeof(mic));
513 if (result < 0)
514 wusb_dev_set_encryption(usb_dev, 0);
515error_dev_set_encryption:
516 kfree(hs);
517error_kzalloc:
518 return result;
519}
520
521/*
522 * Once all connected and authenticated devices have received the new
523 * GTK, switch the host to using it.
524 */
525static void wusbhc_gtk_rekey_work(struct work_struct *work)
526{
527 struct wusbhc *wusbhc = container_of(work,
528 struct wusbhc, gtk_rekey_work);
529 size_t key_size = sizeof(wusbhc->gtk.data);
530 int port_idx;
531 struct wusb_dev *wusb_dev, *wusb_dev_next;
532 LIST_HEAD(rekey_list);
533
534 mutex_lock(&wusbhc->mutex);
535 /* generate the new key */
536 wusbhc_generate_gtk(wusbhc);
537 /* roll the gtk index. */
538 wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1);
539 /*
540 * Save all connected devices on a list while holding wusbhc->mutex and
541 * take a reference to each one. Then submit the set key request to
542 * them after releasing the lock in order to avoid a deadlock.
543 */
544 for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) {
545 wusb_dev = wusbhc->port[port_idx].wusb_dev;
546 if (!wusb_dev || !wusb_dev->usb_dev
547 || !wusb_dev->usb_dev->authenticated)
548 continue;
549
550 wusb_dev_get(wusb_dev);
551 list_add_tail(&wusb_dev->rekey_node, &rekey_list);
552 }
553 mutex_unlock(&wusbhc->mutex);
554
555 /* Submit the rekey requests without holding wusbhc->mutex. */
556 list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list,
557 rekey_node) {
558 list_del_init(&wusb_dev->rekey_node);
559 dev_dbg(&wusb_dev->usb_dev->dev,
560 "%s: rekey device at port %d\n",
561 __func__, wusb_dev->port_idx);
562
563 if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) {
564 dev_err(&wusb_dev->usb_dev->dev,
565 "%s: rekey device at port %d failed\n",
566 __func__, wusb_dev->port_idx);
567 }
568 wusb_dev_put(wusb_dev);
569 }
570
571 /* Switch the host controller to use the new GTK. */
572 mutex_lock(&wusbhc->mutex);
573 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
574 &wusbhc->gtk.descr.bKeyData, key_size);
575 mutex_unlock(&wusbhc->mutex);
576}
577
578/**
579 * wusbhc_gtk_rekey - generate and distribute a new GTK
580 * @wusbhc: the WUSB host controller
581 *
582 * Generate a new GTK and distribute it to all connected and
583 * authenticated devices. When all devices have the new GTK, the host
584 * starts using it.
585 *
586 * This must be called after every device disconnect (see [WUSB]
587 * section 6.2.11.2).
588 */
589void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
590{
591 /*
592 * We need to submit a URB to the downstream WUSB devices in order to
593 * change the group key. This can't be done while holding the
594 * wusbhc->mutex since that is also taken in the urb_enqueue routine
595 * and will cause a deadlock. Instead, queue a work item to do
596 * it when the lock is not held
597 */
598 queue_work(wusbhc->wq_security, &wusbhc->gtk_rekey_work);
599}