Merge branch 'cputime' of git://git390.osdl.marist.edu/pub/scm/linux-2.6
[linux-2.6] / 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/usb/ch9.h>
27 #include <linux/random.h>
28 #include "wusbhc.h"
29
30 static void wusbhc_set_gtk_callback(struct urb *urb);
31 static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
32
33 int wusbhc_sec_create(struct wusbhc *wusbhc)
34 {
35         wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
36         wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
37         wusbhc->gtk.descr.bReserved = 0;
38
39         wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
40                                            WUSB_KEY_INDEX_ORIGINATOR_HOST);
41
42         INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
43
44         return 0;
45 }
46
47
48 /* Called when the HC is destroyed */
49 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
50 {
51 }
52
53
54 /**
55  * wusbhc_next_tkid - generate a new, currently unused, TKID
56  * @wusbhc:   the WUSB host controller
57  * @wusb_dev: the device whose PTK the TKID is for
58  *            (or NULL for a TKID for a GTK)
59  *
60  * The generated TKID consist of two parts: the device's authenicated
61  * address (or 0 or a GTK); and an incrementing number.  This ensures
62  * that TKIDs cannot be shared between devices and by the time the
63  * incrementing number wraps around the older TKIDs will no longer be
64  * in use (a maximum of two keys may be active at any one time).
65  */
66 static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
67 {
68         u32 *tkid;
69         u32 addr;
70
71         if (wusb_dev == NULL) {
72                 tkid = &wusbhc->gtk_tkid;
73                 addr = 0;
74         } else {
75                 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
76                 addr = wusb_dev->addr & 0x7f;
77         }
78
79         *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
80
81         return *tkid;
82 }
83
84 static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
85 {
86         const size_t key_size = sizeof(wusbhc->gtk.data);
87         u32 tkid;
88
89         tkid = wusbhc_next_tkid(wusbhc, NULL);
90
91         wusbhc->gtk.descr.tTKID[0] = (tkid >>  0) & 0xff;
92         wusbhc->gtk.descr.tTKID[1] = (tkid >>  8) & 0xff;
93         wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
94
95         get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
96 }
97
98 /**
99  * wusbhc_sec_start - start the security management process
100  * @wusbhc: the WUSB host controller
101  *
102  * Generate and set an initial GTK on the host controller.
103  *
104  * Called when the HC is started.
105  */
106 int wusbhc_sec_start(struct wusbhc *wusbhc)
107 {
108         const size_t key_size = sizeof(wusbhc->gtk.data);
109         int result;
110
111         wusbhc_generate_gtk(wusbhc);
112
113         result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
114                                  &wusbhc->gtk.descr.bKeyData, key_size);
115         if (result < 0)
116                 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
117                         result);
118
119         return result;
120 }
121
122 /**
123  * wusbhc_sec_stop - stop the security management process
124  * @wusbhc: the WUSB host controller
125  *
126  * Wait for any pending GTK rekeys to stop.
127  */
128 void wusbhc_sec_stop(struct wusbhc *wusbhc)
129 {
130         cancel_work_sync(&wusbhc->gtk_rekey_done_work);
131 }
132
133
134 /** @returns encryption type name */
135 const char *wusb_et_name(u8 x)
136 {
137         switch (x) {
138         case USB_ENC_TYPE_UNSECURE:     return "unsecure";
139         case USB_ENC_TYPE_WIRED:        return "wired";
140         case USB_ENC_TYPE_CCM_1:        return "CCM-1";
141         case USB_ENC_TYPE_RSA_1:        return "RSA-1";
142         default:                        return "unknown";
143         }
144 }
145 EXPORT_SYMBOL_GPL(wusb_et_name);
146
147 /*
148  * Set the device encryption method
149  *
150  * We tell the device which encryption method to use; we do this when
151  * setting up the device's security.
152  */
153 static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
154 {
155         int result;
156         struct device *dev = &usb_dev->dev;
157         struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
158
159         if (value) {
160                 value = wusb_dev->ccm1_etd.bEncryptionValue;
161         } else {
162                 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
163                 value = 0;
164         }
165         /* Set device's */
166         result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
167                         USB_REQ_SET_ENCRYPTION,
168                         USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
169                         value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
170         if (result < 0)
171                 dev_err(dev, "Can't set device's WUSB encryption to "
172                         "%s (value %d): %d\n",
173                         wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
174                         wusb_dev->ccm1_etd.bEncryptionValue,  result);
175         return result;
176 }
177
178 /*
179  * Set the GTK to be used by a device.
180  *
181  * The device must be authenticated.
182  */
183 static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
184 {
185         struct usb_device *usb_dev = wusb_dev->usb_dev;
186
187         return usb_control_msg(
188                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
189                 USB_REQ_SET_DESCRIPTOR,
190                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
191                 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
192                 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
193                 1000);
194 }
195
196
197 /* FIXME: prototype for adding security */
198 int wusb_dev_sec_add(struct wusbhc *wusbhc,
199                      struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
200 {
201         int result, bytes, secd_size;
202         struct device *dev = &usb_dev->dev;
203         struct usb_security_descriptor secd;
204         const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
205         void *secd_buf;
206         const void *itr, *top;
207         char buf[64];
208
209         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
210                                     0, &secd, sizeof(secd));
211         if (result < sizeof(secd)) {
212                 dev_err(dev, "Can't read security descriptor or "
213                         "not enough data: %d\n", result);
214                 goto error_secd;
215         }
216         secd_size = le16_to_cpu(secd.wTotalLength);
217         secd_buf = kmalloc(secd_size, GFP_KERNEL);
218         if (secd_buf == NULL) {
219                 dev_err(dev, "Can't allocate space for security descriptors\n");
220                 goto error_secd_alloc;
221         }
222         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
223                                     0, secd_buf, secd_size);
224         if (result < secd_size) {
225                 dev_err(dev, "Can't read security descriptor or "
226                         "not enough data: %d\n", result);
227                 goto error_secd_all;
228         }
229         bytes = 0;
230         itr = secd_buf + sizeof(secd);
231         top = secd_buf + result;
232         while (itr < top) {
233                 etd = itr;
234                 if (top - itr < sizeof(*etd)) {
235                         dev_err(dev, "BUG: bad device security descriptor; "
236                                 "not enough data (%zu vs %zu bytes left)\n",
237                                 top - itr, sizeof(*etd));
238                         break;
239                 }
240                 if (etd->bLength < sizeof(*etd)) {
241                         dev_err(dev, "BUG: bad device encryption descriptor; "
242                                 "descriptor is too short "
243                                 "(%u vs %zu needed)\n",
244                                 etd->bLength, sizeof(*etd));
245                         break;
246                 }
247                 itr += etd->bLength;
248                 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
249                                   "%s (0x%02x/%02x) ",
250                                   wusb_et_name(etd->bEncryptionType),
251                                   etd->bEncryptionValue, etd->bAuthKeyIndex);
252                 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
253                         ccm1_etd = etd;
254         }
255         /* This code only supports CCM1 as of now. */
256         /* FIXME: user has to choose which sec mode to use?
257          * In theory we want CCM */
258         if (ccm1_etd == NULL) {
259                 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
260                         "can't use!\n");
261                 result = -EINVAL;
262                 goto error_no_ccm1;
263         }
264         wusb_dev->ccm1_etd = *ccm1_etd;
265         dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
266                 buf, wusb_et_name(ccm1_etd->bEncryptionType),
267                 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
268         result = 0;
269         kfree(secd_buf);
270 out:
271         return result;
272
273
274 error_no_ccm1:
275 error_secd_all:
276         kfree(secd_buf);
277 error_secd_alloc:
278 error_secd:
279         goto out;
280 }
281
282 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
283 {
284         /* Nothing so far */
285 }
286
287 /**
288  * Update the address of an unauthenticated WUSB device
289  *
290  * Once we have successfully authenticated, we take it to addr0 state
291  * and then to a normal address.
292  *
293  * Before the device's address (as known by it) was usb_dev->devnum |
294  * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
295  */
296 int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
297 {
298         int result = -ENOMEM;
299         struct usb_device *usb_dev = wusb_dev->usb_dev;
300         struct device *dev = &usb_dev->dev;
301         u8 new_address = wusb_dev->addr & 0x7F;
302
303         /* Set address 0 */
304         result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
305                                  USB_REQ_SET_ADDRESS, 0,
306                                  0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
307         if (result < 0) {
308                 dev_err(dev, "auth failed: can't set address 0: %d\n",
309                         result);
310                 goto error_addr0;
311         }
312         result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
313         if (result < 0)
314                 goto error_addr0;
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_ep0_reinit(usb_dev);
331         usb_dev->authenticated = 1;
332 error_addr:
333 error_addr0:
334         return result;
335 }
336
337 /*
338  *
339  *
340  */
341 /* FIXME: split and cleanup */
342 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
343                             struct wusb_ckhdid *ck)
344 {
345         int result = -ENOMEM;
346         struct usb_device *usb_dev = wusb_dev->usb_dev;
347         struct device *dev = &usb_dev->dev;
348         u32 tkid;
349         __le32 tkid_le;
350         struct usb_handshake *hs;
351         struct aes_ccm_nonce ccm_n;
352         u8 mic[8];
353         struct wusb_keydvt_in keydvt_in;
354         struct wusb_keydvt_out keydvt_out;
355
356         hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
357         if (hs == NULL) {
358                 dev_err(dev, "can't allocate handshake data\n");
359                 goto error_kzalloc;
360         }
361
362         /* We need to turn encryption before beginning the 4way
363          * hshake (WUSB1.0[.3.2.2]) */
364         result = wusb_dev_set_encryption(usb_dev, 1);
365         if (result < 0)
366                 goto error_dev_set_encryption;
367
368         tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
369         tkid_le = cpu_to_le32(tkid);
370
371         hs[0].bMessageNumber = 1;
372         hs[0].bStatus = 0;
373         memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
374         hs[0].bReserved = 0;
375         memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
376         get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
377         memset(hs[0].MIC, 0, sizeof(hs[0].MIC));        /* Per WUSB1.0[T7-22] */
378
379         result = usb_control_msg(
380                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
381                 USB_REQ_SET_HANDSHAKE,
382                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
383                 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
384         if (result < 0) {
385                 dev_err(dev, "Handshake1: request failed: %d\n", result);
386                 goto error_hs1;
387         }
388
389         /* Handshake 2, from the device -- need to verify fields */
390         result = usb_control_msg(
391                 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
392                 USB_REQ_GET_HANDSHAKE,
393                 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
394                 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
395         if (result < 0) {
396                 dev_err(dev, "Handshake2: request failed: %d\n", result);
397                 goto error_hs2;
398         }
399
400         result = -EINVAL;
401         if (hs[1].bMessageNumber != 2) {
402                 dev_err(dev, "Handshake2 failed: bad message number %u\n",
403                         hs[1].bMessageNumber);
404                 goto error_hs2;
405         }
406         if (hs[1].bStatus != 0) {
407                 dev_err(dev, "Handshake2 failed: bad status %u\n",
408                         hs[1].bStatus);
409                 goto error_hs2;
410         }
411         if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
412                 dev_err(dev, "Handshake2 failed: TKID mismatch "
413                         "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
414                         hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
415                         hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
416                 goto error_hs2;
417         }
418         if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
419                 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
420                 goto error_hs2;
421         }
422
423         /* Setup the CCM nonce */
424         memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn));       /* Per WUSB1.0[6.5.2] */
425         memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
426         ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
427         ccm_n.dest_addr.data[0] = wusb_dev->addr;
428         ccm_n.dest_addr.data[1] = 0;
429
430         /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
431         memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
432         memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
433         result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
434         if (result < 0) {
435                 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
436                         result);
437                 goto error_hs2;
438         }
439
440         /* Compute MIC and verify it */
441         result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
442         if (result < 0) {
443                 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
444                         result);
445                 goto error_hs2;
446         }
447
448         if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
449                 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
450                 goto error_hs2;
451         }
452
453         /* Send Handshake3 */
454         hs[2].bMessageNumber = 3;
455         hs[2].bStatus = 0;
456         memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
457         hs[2].bReserved = 0;
458         memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
459         memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
460         result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
461         if (result < 0) {
462                 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
463                         result);
464                 goto error_hs2;
465         }
466
467         result = usb_control_msg(
468                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
469                 USB_REQ_SET_HANDSHAKE,
470                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
471                 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
472         if (result < 0) {
473                 dev_err(dev, "Handshake3: request failed: %d\n", result);
474                 goto error_hs3;
475         }
476
477         result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
478                                  keydvt_out.ptk, sizeof(keydvt_out.ptk));
479         if (result < 0)
480                 goto error_wusbhc_set_ptk;
481
482         result = wusb_dev_set_gtk(wusbhc, wusb_dev);
483         if (result < 0) {
484                 dev_err(dev, "Set GTK for device: request failed: %d\n",
485                         result);
486                 goto error_wusbhc_set_gtk;
487         }
488
489         /* Update the device's address from unauth to auth */
490         if (usb_dev->authenticated == 0) {
491                 result = wusb_dev_update_address(wusbhc, wusb_dev);
492                 if (result < 0)
493                         goto error_dev_update_address;
494         }
495         result = 0;
496         dev_info(dev, "device authenticated\n");
497
498 error_dev_update_address:
499 error_wusbhc_set_gtk:
500 error_wusbhc_set_ptk:
501 error_hs3:
502 error_hs2:
503 error_hs1:
504         memset(hs, 0, 3*sizeof(hs[0]));
505         memset(&keydvt_out, 0, sizeof(keydvt_out));
506         memset(&keydvt_in, 0, sizeof(keydvt_in));
507         memset(&ccm_n, 0, sizeof(ccm_n));
508         memset(mic, 0, sizeof(mic));
509         if (result < 0)
510                 wusb_dev_set_encryption(usb_dev, 0);
511 error_dev_set_encryption:
512         kfree(hs);
513 error_kzalloc:
514         return result;
515 }
516
517 /*
518  * Once all connected and authenticated devices have received the new
519  * GTK, switch the host to using it.
520  */
521 static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
522 {
523         struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
524         size_t key_size = sizeof(wusbhc->gtk.data);
525
526         mutex_lock(&wusbhc->mutex);
527
528         if (--wusbhc->pending_set_gtks == 0)
529                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
530
531         mutex_unlock(&wusbhc->mutex);
532 }
533
534 static void wusbhc_set_gtk_callback(struct urb *urb)
535 {
536         struct wusbhc *wusbhc = urb->context;
537
538         queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
539 }
540
541 /**
542  * wusbhc_gtk_rekey - generate and distribute a new GTK
543  * @wusbhc: the WUSB host controller
544  *
545  * Generate a new GTK and distribute it to all connected and
546  * authenticated devices.  When all devices have the new GTK, the host
547  * starts using it.
548  *
549  * This must be called after every device disconnect (see [WUSB]
550  * section 6.2.11.2).
551  */
552 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
553 {
554         static const size_t key_size = sizeof(wusbhc->gtk.data);
555         int p;
556
557         wusbhc_generate_gtk(wusbhc);
558
559         for (p = 0; p < wusbhc->ports_max; p++) {
560                 struct wusb_dev *wusb_dev;
561
562                 wusb_dev = wusbhc->port[p].wusb_dev;
563                 if (!wusb_dev || !wusb_dev->usb_dev | !wusb_dev->usb_dev->authenticated)
564                         continue;
565
566                 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
567                                      usb_sndctrlpipe(wusb_dev->usb_dev, 0),
568                                      (void *)wusb_dev->set_gtk_req,
569                                      &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
570                                      wusbhc_set_gtk_callback, wusbhc);
571                 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
572                         wusbhc->pending_set_gtks++;
573         }
574         if (wusbhc->pending_set_gtks == 0)
575                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
576 }