Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
[pandora-kernel.git] / drivers / usb / wusbcore / security.c
1 /*
2  * Wireless USB Host Controller
3  * Security support: encryption enablement, etc
4  *
5  * Copyright (C) 2006 Intel Corporation
6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7  *
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.
11  *
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.
16  *
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
20  * 02110-1301, USA.
21  *
22  *
23  * FIXME: docs
24  */
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>
30 #include "wusbhc.h"
31
32 static void wusbhc_set_gtk_callback(struct urb *urb);
33 static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
34
35 int wusbhc_sec_create(struct wusbhc *wusbhc)
36 {
37         wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
38         wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
39         wusbhc->gtk.descr.bReserved = 0;
40
41         wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
42                                            WUSB_KEY_INDEX_ORIGINATOR_HOST);
43
44         INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
45
46         return 0;
47 }
48
49
50 /* Called when the HC is destroyed */
51 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
52 {
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 consist of two parts: the device's authenicated
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  */
68 static 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
86 static 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  */
108 int 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  */
130 void wusbhc_sec_stop(struct wusbhc *wusbhc)
131 {
132         cancel_work_sync(&wusbhc->gtk_rekey_done_work);
133 }
134
135
136 /** @returns encryption type name */
137 const 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 }
147 EXPORT_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  */
155 static 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, 1000 /* FIXME: arbitrary */);
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  */
185 static 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
189         return usb_control_msg(
190                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
191                 USB_REQ_SET_DESCRIPTOR,
192                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
193                 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
194                 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
195                 1000);
196 }
197
198
199 /* FIXME: prototype for adding security */
200 int wusb_dev_sec_add(struct wusbhc *wusbhc,
201                      struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
202 {
203         int result, bytes, secd_size;
204         struct device *dev = &usb_dev->dev;
205         struct usb_security_descriptor *secd;
206         const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
207         const void *itr, *top;
208         char buf[64];
209
210         secd = kmalloc(sizeof(*secd), GFP_KERNEL);
211         if (secd == NULL) {
212                 result = -ENOMEM;
213                 goto out;
214         }
215
216         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
217                                     0, secd, sizeof(*secd));
218         if (result < sizeof(*secd)) {
219                 dev_err(dev, "Can't read security descriptor or "
220                         "not enough data: %d\n", result);
221                 goto out;
222         }
223         secd_size = le16_to_cpu(secd->wTotalLength);
224         secd = krealloc(secd, secd_size, GFP_KERNEL);
225         if (secd == NULL) {
226                 dev_err(dev, "Can't allocate space for security descriptors\n");
227                 goto out;
228         }
229         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
230                                     0, secd, secd_size);
231         if (result < secd_size) {
232                 dev_err(dev, "Can't read security descriptor or "
233                         "not enough data: %d\n", result);
234                 goto out;
235         }
236         bytes = 0;
237         itr = &secd[1];
238         top = (void *)secd + result;
239         while (itr < top) {
240                 etd = itr;
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));
245                         break;
246                 }
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));
252                         break;
253                 }
254                 itr += etd->bLength;
255                 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
256                                   "%s (0x%02x/%02x) ",
257                                   wusb_et_name(etd->bEncryptionType),
258                                   etd->bEncryptionValue, etd->bAuthKeyIndex);
259                 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
260                         ccm1_etd = etd;
261         }
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, "
267                         "can't use!\n");
268                 result = -EINVAL;
269                 goto out;
270         }
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);
275         result = 0;
276 out:
277         kfree(secd);
278         return result;
279 }
280
281 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
282 {
283         /* Nothing so far */
284 }
285
286 /**
287  * Update the address of an unauthenticated WUSB device
288  *
289  * Once we have successfully authenticated, we take it to addr0 state
290  * and then to a normal address.
291  *
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.
294  */
295 int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
296 {
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;
301
302         /* Set address 0 */
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 */);
306         if (result < 0) {
307                 dev_err(dev, "auth failed: can't set address 0: %d\n",
308                         result);
309                 goto error_addr0;
310         }
311         result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
312         if (result < 0)
313                 goto error_addr0;
314         usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
315         usb_ep0_reinit(usb_dev);
316
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 */);
322         if (result < 0) {
323                 dev_err(dev, "auth failed: can't set address %u: %d\n",
324                         new_address, result);
325                 goto error_addr;
326         }
327         result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
328         if (result < 0)
329                 goto error_addr;
330         usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
331         usb_ep0_reinit(usb_dev);
332         usb_dev->authenticated = 1;
333 error_addr:
334 error_addr0:
335         return result;
336 }
337
338 /*
339  *
340  *
341  */
342 /* FIXME: split and cleanup */
343 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
344                             struct wusb_ckhdid *ck)
345 {
346         int result = -ENOMEM;
347         struct usb_device *usb_dev = wusb_dev->usb_dev;
348         struct device *dev = &usb_dev->dev;
349         u32 tkid;
350         __le32 tkid_le;
351         struct usb_handshake *hs;
352         struct aes_ccm_nonce ccm_n;
353         u8 mic[8];
354         struct wusb_keydvt_in keydvt_in;
355         struct wusb_keydvt_out keydvt_out;
356
357         hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
358         if (hs == NULL) {
359                 dev_err(dev, "can't allocate handshake data\n");
360                 goto error_kzalloc;
361         }
362
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);
366         if (result < 0)
367                 goto error_dev_set_encryption;
368
369         tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
370         tkid_le = cpu_to_le32(tkid);
371
372         hs[0].bMessageNumber = 1;
373         hs[0].bStatus = 0;
374         memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
375         hs[0].bReserved = 0;
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] */
379
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 */);
385         if (result < 0) {
386                 dev_err(dev, "Handshake1: request failed: %d\n", result);
387                 goto error_hs1;
388         }
389
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 */);
396         if (result < 0) {
397                 dev_err(dev, "Handshake2: request failed: %d\n", result);
398                 goto error_hs2;
399         }
400
401         result = -EINVAL;
402         if (hs[1].bMessageNumber != 2) {
403                 dev_err(dev, "Handshake2 failed: bad message number %u\n",
404                         hs[1].bMessageNumber);
405                 goto error_hs2;
406         }
407         if (hs[1].bStatus != 0) {
408                 dev_err(dev, "Handshake2 failed: bad status %u\n",
409                         hs[1].bStatus);
410                 goto error_hs2;
411         }
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]);
417                 goto error_hs2;
418         }
419         if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
420                 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
421                 goto error_hs2;
422         }
423
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;
430
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);
435         if (result < 0) {
436                 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
437                         result);
438                 goto error_hs2;
439         }
440
441         /* Compute MIC and verify it */
442         result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
443         if (result < 0) {
444                 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
445                         result);
446                 goto error_hs2;
447         }
448
449         if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
450                 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
451                 goto error_hs2;
452         }
453
454         /* Send Handshake3 */
455         hs[2].bMessageNumber = 3;
456         hs[2].bStatus = 0;
457         memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
458         hs[2].bReserved = 0;
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]);
462         if (result < 0) {
463                 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
464                         result);
465                 goto error_hs2;
466         }
467
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 */);
473         if (result < 0) {
474                 dev_err(dev, "Handshake3: request failed: %d\n", result);
475                 goto error_hs3;
476         }
477
478         result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
479                                  keydvt_out.ptk, sizeof(keydvt_out.ptk));
480         if (result < 0)
481                 goto error_wusbhc_set_ptk;
482
483         result = wusb_dev_set_gtk(wusbhc, wusb_dev);
484         if (result < 0) {
485                 dev_err(dev, "Set GTK for device: request failed: %d\n",
486                         result);
487                 goto error_wusbhc_set_gtk;
488         }
489
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);
493                 if (result < 0)
494                         goto error_dev_update_address;
495         }
496         result = 0;
497         dev_info(dev, "device authenticated\n");
498
499 error_dev_update_address:
500 error_wusbhc_set_gtk:
501 error_wusbhc_set_ptk:
502 error_hs3:
503 error_hs2:
504 error_hs1:
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));
510         if (result < 0)
511                 wusb_dev_set_encryption(usb_dev, 0);
512 error_dev_set_encryption:
513         kfree(hs);
514 error_kzalloc:
515         return result;
516 }
517
518 /*
519  * Once all connected and authenticated devices have received the new
520  * GTK, switch the host to using it.
521  */
522 static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
523 {
524         struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
525         size_t key_size = sizeof(wusbhc->gtk.data);
526
527         mutex_lock(&wusbhc->mutex);
528
529         if (--wusbhc->pending_set_gtks == 0)
530                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
531
532         mutex_unlock(&wusbhc->mutex);
533 }
534
535 static void wusbhc_set_gtk_callback(struct urb *urb)
536 {
537         struct wusbhc *wusbhc = urb->context;
538
539         queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
540 }
541
542 /**
543  * wusbhc_gtk_rekey - generate and distribute a new GTK
544  * @wusbhc: the WUSB host controller
545  *
546  * Generate a new GTK and distribute it to all connected and
547  * authenticated devices.  When all devices have the new GTK, the host
548  * starts using it.
549  *
550  * This must be called after every device disconnect (see [WUSB]
551  * section 6.2.11.2).
552  */
553 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
554 {
555         static const size_t key_size = sizeof(wusbhc->gtk.data);
556         int p;
557
558         wusbhc_generate_gtk(wusbhc);
559
560         for (p = 0; p < wusbhc->ports_max; p++) {
561                 struct wusb_dev *wusb_dev;
562
563                 wusb_dev = wusbhc->port[p].wusb_dev;
564                 if (!wusb_dev || !wusb_dev->usb_dev || !wusb_dev->usb_dev->authenticated)
565                         continue;
566
567                 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
568                                      usb_sndctrlpipe(wusb_dev->usb_dev, 0),
569                                      (void *)wusb_dev->set_gtk_req,
570                                      &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
571                                      wusbhc_set_gtk_callback, wusbhc);
572                 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
573                         wusbhc->pending_set_gtks++;
574         }
575         if (wusbhc->pending_set_gtks == 0)
576                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
577 }