2 * Wireless USB Host Controller
3 * Security support: encryption enablement, etc
5 * Copyright (C) 2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
25 #include <linux/types.h>
26 #include <linux/slab.h>
27 #include <linux/usb/ch9.h>
28 #include <linux/random.h>
29 #include <linux/export.h>
32 static void wusbhc_gtk_rekey_work(struct work_struct
*work
);
34 int wusbhc_sec_create(struct wusbhc
*wusbhc
)
36 wusbhc
->gtk
.descr
.bLength
= sizeof(wusbhc
->gtk
.descr
) + sizeof(wusbhc
->gtk
.data
);
37 wusbhc
->gtk
.descr
.bDescriptorType
= USB_DT_KEY
;
38 wusbhc
->gtk
.descr
.bReserved
= 0;
39 wusbhc
->gtk_index
= 0;
41 INIT_WORK(&wusbhc
->gtk_rekey_work
, wusbhc_gtk_rekey_work
);
47 /* Called when the HC is destroyed */
48 void wusbhc_sec_destroy(struct wusbhc
*wusbhc
)
54 * wusbhc_next_tkid - generate a new, currently unused, TKID
55 * @wusbhc: the WUSB host controller
56 * @wusb_dev: the device whose PTK the TKID is for
57 * (or NULL for a TKID for a GTK)
59 * The generated TKID consist of two parts: the device's authenicated
60 * address (or 0 or a GTK); and an incrementing number. This ensures
61 * that TKIDs cannot be shared between devices and by the time the
62 * incrementing number wraps around the older TKIDs will no longer be
63 * in use (a maximum of two keys may be active at any one time).
65 static u32
wusbhc_next_tkid(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
70 if (wusb_dev
== NULL
) {
71 tkid
= &wusbhc
->gtk_tkid
;
74 tkid
= &wusb_port_by_idx(wusbhc
, wusb_dev
->port_idx
)->ptk_tkid
;
75 addr
= wusb_dev
->addr
& 0x7f;
78 *tkid
= (addr
<< 8) | ((*tkid
+ 1) & 0xff);
83 static void wusbhc_generate_gtk(struct wusbhc
*wusbhc
)
85 const size_t key_size
= sizeof(wusbhc
->gtk
.data
);
88 tkid
= wusbhc_next_tkid(wusbhc
, NULL
);
90 wusbhc
->gtk
.descr
.tTKID
[0] = (tkid
>> 0) & 0xff;
91 wusbhc
->gtk
.descr
.tTKID
[1] = (tkid
>> 8) & 0xff;
92 wusbhc
->gtk
.descr
.tTKID
[2] = (tkid
>> 16) & 0xff;
94 get_random_bytes(wusbhc
->gtk
.descr
.bKeyData
, key_size
);
98 * wusbhc_sec_start - start the security management process
99 * @wusbhc: the WUSB host controller
101 * Generate and set an initial GTK on the host controller.
103 * Called when the HC is started.
105 int wusbhc_sec_start(struct wusbhc
*wusbhc
)
107 const size_t key_size
= sizeof(wusbhc
->gtk
.data
);
110 wusbhc_generate_gtk(wusbhc
);
112 result
= wusbhc
->set_gtk(wusbhc
, wusbhc
->gtk_tkid
,
113 &wusbhc
->gtk
.descr
.bKeyData
, key_size
);
115 dev_err(wusbhc
->dev
, "cannot set GTK for the host: %d\n",
122 * wusbhc_sec_stop - stop the security management process
123 * @wusbhc: the WUSB host controller
125 * Wait for any pending GTK rekeys to stop.
127 void wusbhc_sec_stop(struct wusbhc
*wusbhc
)
129 cancel_work_sync(&wusbhc
->gtk_rekey_work
);
133 /** @returns encryption type name */
134 const char *wusb_et_name(u8 x
)
137 case USB_ENC_TYPE_UNSECURE
: return "unsecure";
138 case USB_ENC_TYPE_WIRED
: return "wired";
139 case USB_ENC_TYPE_CCM_1
: return "CCM-1";
140 case USB_ENC_TYPE_RSA_1
: return "RSA-1";
141 default: return "unknown";
144 EXPORT_SYMBOL_GPL(wusb_et_name
);
147 * Set the device encryption method
149 * We tell the device which encryption method to use; we do this when
150 * setting up the device's security.
152 static int wusb_dev_set_encryption(struct usb_device
*usb_dev
, int value
)
155 struct device
*dev
= &usb_dev
->dev
;
156 struct wusb_dev
*wusb_dev
= usb_dev
->wusb_dev
;
159 value
= wusb_dev
->ccm1_etd
.bEncryptionValue
;
161 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
165 result
= usb_control_msg(usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
166 USB_REQ_SET_ENCRYPTION
,
167 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
168 value
, 0, NULL
, 0, 1000 /* FIXME: arbitrary */);
170 dev_err(dev
, "Can't set device's WUSB encryption to "
171 "%s (value %d): %d\n",
172 wusb_et_name(wusb_dev
->ccm1_etd
.bEncryptionType
),
173 wusb_dev
->ccm1_etd
.bEncryptionValue
, result
);
178 * Set the GTK to be used by a device.
180 * The device must be authenticated.
182 static int wusb_dev_set_gtk(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
184 struct usb_device
*usb_dev
= wusb_dev
->usb_dev
;
185 u8 key_index
= wusb_key_index(wusbhc
->gtk_index
,
186 WUSB_KEY_INDEX_TYPE_GTK
, WUSB_KEY_INDEX_ORIGINATOR_HOST
);
188 return usb_control_msg(
189 usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
190 USB_REQ_SET_DESCRIPTOR
,
191 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
192 USB_DT_KEY
<< 8 | key_index
, 0,
193 &wusbhc
->gtk
.descr
, wusbhc
->gtk
.descr
.bLength
,
198 /* FIXME: prototype for adding security */
199 int wusb_dev_sec_add(struct wusbhc
*wusbhc
,
200 struct usb_device
*usb_dev
, struct wusb_dev
*wusb_dev
)
202 int result
, bytes
, secd_size
;
203 struct device
*dev
= &usb_dev
->dev
;
204 struct usb_security_descriptor
*secd
, *new_secd
;
205 const struct usb_encryption_descriptor
*etd
, *ccm1_etd
= NULL
;
206 const void *itr
, *top
;
209 secd
= kmalloc(sizeof(*secd
), GFP_KERNEL
);
215 result
= usb_get_descriptor(usb_dev
, USB_DT_SECURITY
,
216 0, secd
, sizeof(*secd
));
217 if (result
< sizeof(*secd
)) {
218 dev_err(dev
, "Can't read security descriptor or "
219 "not enough data: %d\n", result
);
222 secd_size
= le16_to_cpu(secd
->wTotalLength
);
223 new_secd
= krealloc(secd
, secd_size
, GFP_KERNEL
);
224 if (new_secd
== NULL
) {
225 dev_err(dev
, "Can't allocate space for security descriptors\n");
229 result
= usb_get_descriptor(usb_dev
, USB_DT_SECURITY
,
231 if (result
< secd_size
) {
232 dev_err(dev
, "Can't read security descriptor or "
233 "not enough data: %d\n", result
);
238 top
= (void *)secd
+ result
;
241 if (top
- itr
< sizeof(*etd
)) {
242 dev_err(dev
, "BUG: bad device security descriptor; "
243 "not enough data (%zu vs %zu bytes left)\n",
244 top
- itr
, sizeof(*etd
));
247 if (etd
->bLength
< sizeof(*etd
)) {
248 dev_err(dev
, "BUG: bad device encryption descriptor; "
249 "descriptor is too short "
250 "(%u vs %zu needed)\n",
251 etd
->bLength
, sizeof(*etd
));
255 bytes
+= snprintf(buf
+ bytes
, sizeof(buf
) - bytes
,
257 wusb_et_name(etd
->bEncryptionType
),
258 etd
->bEncryptionValue
, etd
->bAuthKeyIndex
);
259 if (etd
->bEncryptionType
== USB_ENC_TYPE_CCM_1
)
262 /* This code only supports CCM1 as of now. */
263 /* FIXME: user has to choose which sec mode to use?
264 * In theory we want CCM */
265 if (ccm1_etd
== NULL
) {
266 dev_err(dev
, "WUSB device doesn't support CCM1 encryption, "
271 wusb_dev
->ccm1_etd
= *ccm1_etd
;
272 dev_dbg(dev
, "supported encryption: %s; using %s (0x%02x/%02x)\n",
273 buf
, wusb_et_name(ccm1_etd
->bEncryptionType
),
274 ccm1_etd
->bEncryptionValue
, ccm1_etd
->bAuthKeyIndex
);
281 void wusb_dev_sec_rm(struct wusb_dev
*wusb_dev
)
287 * Update the address of an unauthenticated WUSB device
289 * Once we have successfully authenticated, we take it to addr0 state
290 * and then to a normal address.
292 * Before the device's address (as known by it) was usb_dev->devnum |
293 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
295 int wusb_dev_update_address(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
)
297 int result
= -ENOMEM
;
298 struct usb_device
*usb_dev
= wusb_dev
->usb_dev
;
299 struct device
*dev
= &usb_dev
->dev
;
300 u8 new_address
= wusb_dev
->addr
& 0x7F;
303 result
= usb_control_msg(usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
304 USB_REQ_SET_ADDRESS
, 0,
305 0, 0, NULL
, 0, 1000 /* FIXME: arbitrary */);
307 dev_err(dev
, "auth failed: can't set address 0: %d\n",
311 result
= wusb_set_dev_addr(wusbhc
, wusb_dev
, 0);
314 usb_set_device_state(usb_dev
, USB_STATE_DEFAULT
);
315 usb_ep0_reinit(usb_dev
);
317 /* Set new (authenticated) address. */
318 result
= usb_control_msg(usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
319 USB_REQ_SET_ADDRESS
, 0,
320 new_address
, 0, NULL
, 0,
321 1000 /* FIXME: arbitrary */);
323 dev_err(dev
, "auth failed: can't set address %u: %d\n",
324 new_address
, result
);
327 result
= wusb_set_dev_addr(wusbhc
, wusb_dev
, new_address
);
330 usb_set_device_state(usb_dev
, USB_STATE_ADDRESS
);
331 usb_ep0_reinit(usb_dev
);
332 usb_dev
->authenticated
= 1;
342 /* FIXME: split and cleanup */
343 int wusb_dev_4way_handshake(struct wusbhc
*wusbhc
, struct wusb_dev
*wusb_dev
,
344 struct wusb_ckhdid
*ck
)
346 int result
= -ENOMEM
;
347 struct usb_device
*usb_dev
= wusb_dev
->usb_dev
;
348 struct device
*dev
= &usb_dev
->dev
;
351 struct usb_handshake
*hs
;
352 struct aes_ccm_nonce ccm_n
;
354 struct wusb_keydvt_in keydvt_in
;
355 struct wusb_keydvt_out keydvt_out
;
357 hs
= kcalloc(3, sizeof(hs
[0]), GFP_KERNEL
);
359 dev_err(dev
, "can't allocate handshake data\n");
363 /* We need to turn encryption before beginning the 4way
364 * hshake (WUSB1.0[.3.2.2]) */
365 result
= wusb_dev_set_encryption(usb_dev
, 1);
367 goto error_dev_set_encryption
;
369 tkid
= wusbhc_next_tkid(wusbhc
, wusb_dev
);
370 tkid_le
= cpu_to_le32(tkid
);
372 hs
[0].bMessageNumber
= 1;
374 memcpy(hs
[0].tTKID
, &tkid_le
, sizeof(hs
[0].tTKID
));
376 memcpy(hs
[0].CDID
, &wusb_dev
->cdid
, sizeof(hs
[0].CDID
));
377 get_random_bytes(&hs
[0].nonce
, sizeof(hs
[0].nonce
));
378 memset(hs
[0].MIC
, 0, sizeof(hs
[0].MIC
)); /* Per WUSB1.0[T7-22] */
380 result
= usb_control_msg(
381 usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
382 USB_REQ_SET_HANDSHAKE
,
383 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
384 1, 0, &hs
[0], sizeof(hs
[0]), 1000 /* FIXME: arbitrary */);
386 dev_err(dev
, "Handshake1: request failed: %d\n", result
);
390 /* Handshake 2, from the device -- need to verify fields */
391 result
= usb_control_msg(
392 usb_dev
, usb_rcvctrlpipe(usb_dev
, 0),
393 USB_REQ_GET_HANDSHAKE
,
394 USB_DIR_IN
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
395 2, 0, &hs
[1], sizeof(hs
[1]), 1000 /* FIXME: arbitrary */);
397 dev_err(dev
, "Handshake2: request failed: %d\n", result
);
402 if (hs
[1].bMessageNumber
!= 2) {
403 dev_err(dev
, "Handshake2 failed: bad message number %u\n",
404 hs
[1].bMessageNumber
);
407 if (hs
[1].bStatus
!= 0) {
408 dev_err(dev
, "Handshake2 failed: bad status %u\n",
412 if (memcmp(hs
[0].tTKID
, hs
[1].tTKID
, sizeof(hs
[0].tTKID
))) {
413 dev_err(dev
, "Handshake2 failed: TKID mismatch "
414 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
415 hs
[0].tTKID
[0], hs
[0].tTKID
[1], hs
[0].tTKID
[2],
416 hs
[1].tTKID
[0], hs
[1].tTKID
[1], hs
[1].tTKID
[2]);
419 if (memcmp(hs
[0].CDID
, hs
[1].CDID
, sizeof(hs
[0].CDID
))) {
420 dev_err(dev
, "Handshake2 failed: CDID mismatch\n");
424 /* Setup the CCM nonce */
425 memset(&ccm_n
.sfn
, 0, sizeof(ccm_n
.sfn
)); /* Per WUSB1.0[6.5.2] */
426 memcpy(ccm_n
.tkid
, &tkid_le
, sizeof(ccm_n
.tkid
));
427 ccm_n
.src_addr
= wusbhc
->uwb_rc
->uwb_dev
.dev_addr
;
428 ccm_n
.dest_addr
.data
[0] = wusb_dev
->addr
;
429 ccm_n
.dest_addr
.data
[1] = 0;
431 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
432 memcpy(keydvt_in
.hnonce
, hs
[0].nonce
, sizeof(keydvt_in
.hnonce
));
433 memcpy(keydvt_in
.dnonce
, hs
[1].nonce
, sizeof(keydvt_in
.dnonce
));
434 result
= wusb_key_derive(&keydvt_out
, ck
->data
, &ccm_n
, &keydvt_in
);
436 dev_err(dev
, "Handshake2 failed: cannot derive keys: %d\n",
441 /* Compute MIC and verify it */
442 result
= wusb_oob_mic(mic
, keydvt_out
.kck
, &ccm_n
, &hs
[1]);
444 dev_err(dev
, "Handshake2 failed: cannot compute MIC: %d\n",
449 if (memcmp(hs
[1].MIC
, mic
, sizeof(hs
[1].MIC
))) {
450 dev_err(dev
, "Handshake2 failed: MIC mismatch\n");
454 /* Send Handshake3 */
455 hs
[2].bMessageNumber
= 3;
457 memcpy(hs
[2].tTKID
, &tkid_le
, sizeof(hs
[2].tTKID
));
459 memcpy(hs
[2].CDID
, &wusb_dev
->cdid
, sizeof(hs
[2].CDID
));
460 memcpy(hs
[2].nonce
, hs
[0].nonce
, sizeof(hs
[2].nonce
));
461 result
= wusb_oob_mic(hs
[2].MIC
, keydvt_out
.kck
, &ccm_n
, &hs
[2]);
463 dev_err(dev
, "Handshake3 failed: cannot compute MIC: %d\n",
468 result
= usb_control_msg(
469 usb_dev
, usb_sndctrlpipe(usb_dev
, 0),
470 USB_REQ_SET_HANDSHAKE
,
471 USB_DIR_OUT
| USB_TYPE_STANDARD
| USB_RECIP_DEVICE
,
472 3, 0, &hs
[2], sizeof(hs
[2]), 1000 /* FIXME: arbitrary */);
474 dev_err(dev
, "Handshake3: request failed: %d\n", result
);
478 result
= wusbhc
->set_ptk(wusbhc
, wusb_dev
->port_idx
, tkid
,
479 keydvt_out
.ptk
, sizeof(keydvt_out
.ptk
));
481 goto error_wusbhc_set_ptk
;
483 result
= wusb_dev_set_gtk(wusbhc
, wusb_dev
);
485 dev_err(dev
, "Set GTK for device: request failed: %d\n",
487 goto error_wusbhc_set_gtk
;
490 /* Update the device's address from unauth to auth */
491 if (usb_dev
->authenticated
== 0) {
492 result
= wusb_dev_update_address(wusbhc
, wusb_dev
);
494 goto error_dev_update_address
;
497 dev_info(dev
, "device authenticated\n");
499 error_dev_update_address
:
500 error_wusbhc_set_gtk
:
501 error_wusbhc_set_ptk
:
505 memset(hs
, 0, 3*sizeof(hs
[0]));
506 memset(&keydvt_out
, 0, sizeof(keydvt_out
));
507 memset(&keydvt_in
, 0, sizeof(keydvt_in
));
508 memset(&ccm_n
, 0, sizeof(ccm_n
));
509 memset(mic
, 0, sizeof(mic
));
511 wusb_dev_set_encryption(usb_dev
, 0);
512 error_dev_set_encryption
:
519 * Once all connected and authenticated devices have received the new
520 * GTK, switch the host to using it.
522 static void wusbhc_gtk_rekey_work(struct work_struct
*work
)
524 struct wusbhc
*wusbhc
= container_of(work
,
525 struct wusbhc
, gtk_rekey_work
);
526 size_t key_size
= sizeof(wusbhc
->gtk
.data
);
528 struct wusb_dev
*wusb_dev
, *wusb_dev_next
;
529 LIST_HEAD(rekey_list
);
531 mutex_lock(&wusbhc
->mutex
);
532 /* generate the new key */
533 wusbhc_generate_gtk(wusbhc
);
534 /* roll the gtk index. */
535 wusbhc
->gtk_index
= (wusbhc
->gtk_index
+ 1) % (WUSB_KEY_INDEX_MAX
+ 1);
537 * Save all connected devices on a list while holding wusbhc->mutex and
538 * take a reference to each one. Then submit the set key request to
539 * them after releasing the lock in order to avoid a deadlock.
541 for (port_idx
= 0; port_idx
< wusbhc
->ports_max
; port_idx
++) {
542 wusb_dev
= wusbhc
->port
[port_idx
].wusb_dev
;
543 if (!wusb_dev
|| !wusb_dev
->usb_dev
544 || !wusb_dev
->usb_dev
->authenticated
)
547 wusb_dev_get(wusb_dev
);
548 list_add_tail(&wusb_dev
->rekey_node
, &rekey_list
);
550 mutex_unlock(&wusbhc
->mutex
);
552 /* Submit the rekey requests without holding wusbhc->mutex. */
553 list_for_each_entry_safe(wusb_dev
, wusb_dev_next
, &rekey_list
,
555 list_del_init(&wusb_dev
->rekey_node
);
556 dev_dbg(&wusb_dev
->usb_dev
->dev
, "%s: rekey device at port %d\n",
557 __func__
, wusb_dev
->port_idx
);
559 if (wusb_dev_set_gtk(wusbhc
, wusb_dev
) < 0) {
560 dev_err(&wusb_dev
->usb_dev
->dev
, "%s: rekey device at port %d failed\n",
561 __func__
, wusb_dev
->port_idx
);
563 wusb_dev_put(wusb_dev
);
566 /* Switch the host controller to use the new GTK. */
567 mutex_lock(&wusbhc
->mutex
);
568 wusbhc
->set_gtk(wusbhc
, wusbhc
->gtk_tkid
,
569 &wusbhc
->gtk
.descr
.bKeyData
, key_size
);
570 mutex_unlock(&wusbhc
->mutex
);
574 * wusbhc_gtk_rekey - generate and distribute a new GTK
575 * @wusbhc: the WUSB host controller
577 * Generate a new GTK and distribute it to all connected and
578 * authenticated devices. When all devices have the new GTK, the host
581 * This must be called after every device disconnect (see [WUSB]
584 void wusbhc_gtk_rekey(struct wusbhc
*wusbhc
)
587 * We need to submit a URB to the downstream WUSB devices in order to
588 * change the group key. This can't be done while holding the
589 * wusbhc->mutex since that is also taken in the urb_enqueue routine
590 * and will cause a deadlock. Instead, queue a work item to do
591 * it when the lock is not held
593 queue_work(wusbd
, &wusbhc
->gtk_rekey_work
);