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 32static void wusbhc_gtk_rekey_work(struct work_struct *work); 33 34int wusbhc_sec_create(struct wusbhc *wusbhc) 35{ 36 /* 37 * WQ is singlethread because we need to serialize rekey operations. 38 * Use a separate workqueue for security operations instead of the 39 * wusbd workqueue because security operations may need to communicate 40 * directly with downstream wireless devices using synchronous URBs. 41 * If a device is not responding, this could block other host 42 * controller operations. 43 */ 44 wusbhc->wq_security = create_singlethread_workqueue("wusbd_security"); 45 if (wusbhc->wq_security == NULL) { 46 pr_err("WUSB-core: Cannot create wusbd_security workqueue\n"); 47 return -ENOMEM; 48 } 49 50 wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + 51 sizeof(wusbhc->gtk.data); 52 wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY; 53 wusbhc->gtk.descr.bReserved = 0; 54 wusbhc->gtk_index = 0; 55 56 INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work); 57 58 return 0; 59} 60 61 62/* Called when the HC is destroyed */ 63void wusbhc_sec_destroy(struct wusbhc *wusbhc) 64{ 65 destroy_workqueue(wusbhc->wq_security); 66} 67 68 69/** 70 * wusbhc_next_tkid - generate a new, currently unused, TKID 71 * @wusbhc: the WUSB host controller 72 * @wusb_dev: the device whose PTK the TKID is for 73 * (or NULL for a TKID for a GTK) 74 * 75 * The generated TKID consists of two parts: the device's authenticated 76 * address (or 0 or a GTK); and an incrementing number. This ensures 77 * that TKIDs cannot be shared between devices and by the time the 78 * incrementing number wraps around the older TKIDs will no longer be 79 * in use (a maximum of two keys may be active at any one time). 80 */ 81static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) 82{ 83 u32 *tkid; 84 u32 addr; 85 86 if (wusb_dev == NULL) { 87 tkid = &wusbhc->gtk_tkid; 88 addr = 0; 89 } else { 90 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid; 91 addr = wusb_dev->addr & 0x7f; 92 } 93 94 *tkid = (addr << 8) | ((*tkid + 1) & 0xff); 95 96 return *tkid; 97} 98 99static void wusbhc_generate_gtk(struct wusbhc *wusbhc) 100{ 101 const size_t key_size = sizeof(wusbhc->gtk.data); 102 u32 tkid; 103 104 tkid = wusbhc_next_tkid(wusbhc, NULL); 105 106 wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff; 107 wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff; 108 wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff; 109 110 get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size); 111} 112 113/** 114 * wusbhc_sec_start - start the security management process 115 * @wusbhc: the WUSB host controller 116 * 117 * Generate and set an initial GTK on the host controller. 118 * 119 * Called when the HC is started. 120 */ 121int wusbhc_sec_start(struct wusbhc *wusbhc) 122{ 123 const size_t key_size = sizeof(wusbhc->gtk.data); 124 int result; 125 126 wusbhc_generate_gtk(wusbhc); 127 128 result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, 129 &wusbhc->gtk.descr.bKeyData, key_size); 130 if (result < 0) 131 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n", 132 result); 133 134 return result; 135} 136 137/** 138 * wusbhc_sec_stop - stop the security management process 139 * @wusbhc: the WUSB host controller 140 * 141 * Wait for any pending GTK rekeys to stop. 142 */ 143void wusbhc_sec_stop(struct wusbhc *wusbhc) 144{ 145 cancel_work_sync(&wusbhc->gtk_rekey_work); 146} 147 148 149/** @returns encryption type name */ 150const char *wusb_et_name(u8 x) 151{ 152 switch (x) { 153 case USB_ENC_TYPE_UNSECURE: return "unsecure"; 154 case USB_ENC_TYPE_WIRED: return "wired"; 155 case USB_ENC_TYPE_CCM_1: return "CCM-1"; 156 case USB_ENC_TYPE_RSA_1: return "RSA-1"; 157 default: return "unknown"; 158 } 159} 160EXPORT_SYMBOL_GPL(wusb_et_name); 161 162/* 163 * Set the device encryption method 164 * 165 * We tell the device which encryption method to use; we do this when 166 * setting up the device's security. 167 */ 168static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value) 169{ 170 int result; 171 struct device *dev = &usb_dev->dev; 172 struct wusb_dev *wusb_dev = usb_dev->wusb_dev; 173 174 if (value) { 175 value = wusb_dev->ccm1_etd.bEncryptionValue; 176 } else { 177 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */ 178 value = 0; 179 } 180 /* Set device's */ 181 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), 182 USB_REQ_SET_ENCRYPTION, 183 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 184 value, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); 185 if (result < 0) 186 dev_err(dev, "Can't set device's WUSB encryption to " 187 "%s (value %d): %d\n", 188 wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType), 189 wusb_dev->ccm1_etd.bEncryptionValue, result); 190 return result; 191} 192 193/* 194 * Set the GTK to be used by a device. 195 * 196 * The device must be authenticated. 197 */ 198static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) 199{ 200 struct usb_device *usb_dev = wusb_dev->usb_dev; 201 u8 key_index = wusb_key_index(wusbhc->gtk_index, 202 WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST); 203 204 return usb_control_msg( 205 usb_dev, usb_sndctrlpipe(usb_dev, 0), 206 USB_REQ_SET_DESCRIPTOR, 207 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 208 USB_DT_KEY << 8 | key_index, 0, 209 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength, 210 USB_CTRL_SET_TIMEOUT); 211} 212 213 214/* FIXME: prototype for adding security */ 215int wusb_dev_sec_add(struct wusbhc *wusbhc, 216 struct usb_device *usb_dev, struct wusb_dev *wusb_dev) 217{ 218 int result, bytes, secd_size; 219 struct device *dev = &usb_dev->dev; 220 struct usb_security_descriptor *secd, *new_secd; 221 const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL; 222 const void *itr, *top; 223 char buf[64]; 224 225 secd = kmalloc(sizeof(*secd), GFP_KERNEL); 226 if (secd == NULL) { 227 result = -ENOMEM; 228 goto out; 229 } 230 231 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY, 232 0, secd, sizeof(*secd)); 233 if (result < sizeof(*secd)) { 234 dev_err(dev, "Can't read security descriptor or " 235 "not enough data: %d\n", result); 236 goto out; 237 } 238 secd_size = le16_to_cpu(secd->wTotalLength); 239 new_secd = krealloc(secd, secd_size, GFP_KERNEL); 240 if (new_secd == NULL) { 241 dev_err(dev, 242 "Can't allocate space for security descriptors\n"); 243 goto out; 244 } 245 secd = new_secd; 246 result = usb_get_descriptor(usb_dev, USB_DT_SECURITY, 247 0, secd, secd_size); 248 if (result < secd_size) { 249 dev_err(dev, "Can't read security descriptor or " 250 "not enough data: %d\n", result); 251 goto out; 252 } 253 bytes = 0; 254 itr = &secd[1]; 255 top = (void *)secd + result; 256 while (itr < top) { 257 etd = itr; 258 if (top - itr < sizeof(*etd)) { 259 dev_err(dev, "BUG: bad device security descriptor; " 260 "not enough data (%zu vs %zu bytes left)\n", 261 top - itr, sizeof(*etd)); 262 break; 263 } 264 if (etd->bLength < sizeof(*etd)) { 265 dev_err(dev, "BUG: bad device encryption descriptor; " 266 "descriptor is too short " 267 "(%u vs %zu needed)\n", 268 etd->bLength, sizeof(*etd)); 269 break; 270 } 271 itr += etd->bLength; 272 bytes += snprintf(buf + bytes, sizeof(buf) - bytes, 273 "%s (0x%02x/%02x) ", 274 wusb_et_name(etd->bEncryptionType), 275 etd->bEncryptionValue, etd->bAuthKeyIndex); 276 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1) 277 ccm1_etd = etd; 278 } 279 /* This code only supports CCM1 as of now. */ 280 /* FIXME: user has to choose which sec mode to use? 281 * In theory we want CCM */ 282 if (ccm1_etd == NULL) { 283 dev_err(dev, "WUSB device doesn't support CCM1 encryption, " 284 "can't use!\n"); 285 result = -EINVAL; 286 goto out; 287 } 288 wusb_dev->ccm1_etd = *ccm1_etd; 289 dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n", 290 buf, wusb_et_name(ccm1_etd->bEncryptionType), 291 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex); 292 result = 0; 293out: 294 kfree(secd); 295 return result; 296} 297 298void wusb_dev_sec_rm(struct wusb_dev *wusb_dev) 299{ 300 /* Nothing so far */ 301} 302 303/** 304 * Update the address of an unauthenticated WUSB device 305 * 306 * Once we have successfully authenticated, we take it to addr0 state 307 * and then to a normal address. 308 * 309 * Before the device's address (as known by it) was usb_dev->devnum | 310 * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum. 311 */ 312int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) 313{ 314 int result = -ENOMEM; 315 struct usb_device *usb_dev = wusb_dev->usb_dev; 316 struct device *dev = &usb_dev->dev; 317 u8 new_address = wusb_dev->addr & 0x7F; 318 319 /* Set address 0 */ 320 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), 321 USB_REQ_SET_ADDRESS, 322 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 323 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); 324 if (result < 0) { 325 dev_err(dev, "auth failed: can't set address 0: %d\n", 326 result); 327 goto error_addr0; 328 } 329 result = wusb_set_dev_addr(wusbhc, wusb_dev, 0); 330 if (result < 0) 331 goto error_addr0; 332 usb_set_device_state(usb_dev, USB_STATE_DEFAULT); 333 usb_ep0_reinit(usb_dev); 334 335 /* Set new (authenticated) address. */ 336 result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), 337 USB_REQ_SET_ADDRESS, 338 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 339 new_address, 0, NULL, 0, 340 USB_CTRL_SET_TIMEOUT); 341 if (result < 0) { 342 dev_err(dev, "auth failed: can't set address %u: %d\n", 343 new_address, result); 344 goto error_addr; 345 } 346 result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address); 347 if (result < 0) 348 goto error_addr; 349 usb_set_device_state(usb_dev, USB_STATE_ADDRESS); 350 usb_ep0_reinit(usb_dev); 351 usb_dev->authenticated = 1; 352error_addr: 353error_addr0: 354 return result; 355} 356 357/* 358 * 359 * 360 */ 361/* FIXME: split and cleanup */ 362int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev, 363 struct wusb_ckhdid *ck) 364{ 365 int result = -ENOMEM; 366 struct usb_device *usb_dev = wusb_dev->usb_dev; 367 struct device *dev = &usb_dev->dev; 368 u32 tkid; 369 __le32 tkid_le; 370 struct usb_handshake *hs; 371 struct aes_ccm_nonce ccm_n; 372 u8 mic[8]; 373 struct wusb_keydvt_in keydvt_in; 374 struct wusb_keydvt_out keydvt_out; 375 376 hs = kcalloc(3, sizeof(hs[0]), GFP_KERNEL); 377 if (hs == NULL) { 378 dev_err(dev, "can't allocate handshake data\n"); 379 goto error_kzalloc; 380 } 381 382 /* We need to turn encryption before beginning the 4way 383 * hshake (WUSB1.0[.3.2.2]) */ 384 result = wusb_dev_set_encryption(usb_dev, 1); 385 if (result < 0) 386 goto error_dev_set_encryption; 387 388 tkid = wusbhc_next_tkid(wusbhc, wusb_dev); 389 tkid_le = cpu_to_le32(tkid); 390 391 hs[0].bMessageNumber = 1; 392 hs[0].bStatus = 0; 393 memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID)); 394 hs[0].bReserved = 0; 395 memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID)); 396 get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce)); 397 memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */ 398 399 result = usb_control_msg( 400 usb_dev, usb_sndctrlpipe(usb_dev, 0), 401 USB_REQ_SET_HANDSHAKE, 402 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 403 1, 0, &hs[0], sizeof(hs[0]), USB_CTRL_SET_TIMEOUT); 404 if (result < 0) { 405 dev_err(dev, "Handshake1: request failed: %d\n", result); 406 goto error_hs1; 407 } 408 409 /* Handshake 2, from the device -- need to verify fields */ 410 result = usb_control_msg( 411 usb_dev, usb_rcvctrlpipe(usb_dev, 0), 412 USB_REQ_GET_HANDSHAKE, 413 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 414 2, 0, &hs[1], sizeof(hs[1]), USB_CTRL_GET_TIMEOUT); 415 if (result < 0) { 416 dev_err(dev, "Handshake2: request failed: %d\n", result); 417 goto error_hs2; 418 } 419 420 result = -EINVAL; 421 if (hs[1].bMessageNumber != 2) { 422 dev_err(dev, "Handshake2 failed: bad message number %u\n", 423 hs[1].bMessageNumber); 424 goto error_hs2; 425 } 426 if (hs[1].bStatus != 0) { 427 dev_err(dev, "Handshake2 failed: bad status %u\n", 428 hs[1].bStatus); 429 goto error_hs2; 430 } 431 if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) { 432 dev_err(dev, "Handshake2 failed: TKID mismatch " 433 "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n", 434 hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2], 435 hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]); 436 goto error_hs2; 437 } 438 if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) { 439 dev_err(dev, "Handshake2 failed: CDID mismatch\n"); 440 goto error_hs2; 441 } 442 443 /* Setup the CCM nonce */ 444 memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */ 445 memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid)); 446 ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr; 447 ccm_n.dest_addr.data[0] = wusb_dev->addr; 448 ccm_n.dest_addr.data[1] = 0; 449 450 /* Derive the KCK and PTK from CK, the CCM, H and D nonces */ 451 memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce)); 452 memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce)); 453 result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in); 454 if (result < 0) { 455 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n", 456 result); 457 goto error_hs2; 458 } 459 460 /* Compute MIC and verify it */ 461 result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]); 462 if (result < 0) { 463 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n", 464 result); 465 goto error_hs2; 466 } 467 468 if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) { 469 dev_err(dev, "Handshake2 failed: MIC mismatch\n"); 470 goto error_hs2; 471 } 472 473 /* Send Handshake3 */ 474 hs[2].bMessageNumber = 3; 475 hs[2].bStatus = 0; 476 memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID)); 477 hs[2].bReserved = 0; 478 memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID)); 479 memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce)); 480 result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]); 481 if (result < 0) { 482 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n", 483 result); 484 goto error_hs2; 485 } 486 487 result = usb_control_msg( 488 usb_dev, usb_sndctrlpipe(usb_dev, 0), 489 USB_REQ_SET_HANDSHAKE, 490 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 491 3, 0, &hs[2], sizeof(hs[2]), USB_CTRL_SET_TIMEOUT); 492 if (result < 0) { 493 dev_err(dev, "Handshake3: request failed: %d\n", result); 494 goto error_hs3; 495 } 496 497 result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid, 498 keydvt_out.ptk, sizeof(keydvt_out.ptk)); 499 if (result < 0) 500 goto error_wusbhc_set_ptk; 501 502 result = wusb_dev_set_gtk(wusbhc, wusb_dev); 503 if (result < 0) { 504 dev_err(dev, "Set GTK for device: request failed: %d\n", 505 result); 506 goto error_wusbhc_set_gtk; 507 } 508 509 /* Update the device's address from unauth to auth */ 510 if (usb_dev->authenticated == 0) { 511 result = wusb_dev_update_address(wusbhc, wusb_dev); 512 if (result < 0) 513 goto error_dev_update_address; 514 } 515 result = 0; 516 dev_info(dev, "device authenticated\n"); 517 518error_dev_update_address: 519error_wusbhc_set_gtk: 520error_wusbhc_set_ptk: 521error_hs3: 522error_hs2: 523error_hs1: 524 memset(hs, 0, 3*sizeof(hs[0])); 525 memset(&keydvt_out, 0, sizeof(keydvt_out)); 526 memset(&keydvt_in, 0, sizeof(keydvt_in)); 527 memset(&ccm_n, 0, sizeof(ccm_n)); 528 memset(mic, 0, sizeof(mic)); 529 if (result < 0) 530 wusb_dev_set_encryption(usb_dev, 0); 531error_dev_set_encryption: 532 kfree(hs); 533error_kzalloc: 534 return result; 535} 536 537/* 538 * Once all connected and authenticated devices have received the new 539 * GTK, switch the host to using it. 540 */ 541static void wusbhc_gtk_rekey_work(struct work_struct *work) 542{ 543 struct wusbhc *wusbhc = container_of(work, 544 struct wusbhc, gtk_rekey_work); 545 size_t key_size = sizeof(wusbhc->gtk.data); 546 int port_idx; 547 struct wusb_dev *wusb_dev, *wusb_dev_next; 548 LIST_HEAD(rekey_list); 549 550 mutex_lock(&wusbhc->mutex); 551 /* generate the new key */ 552 wusbhc_generate_gtk(wusbhc); 553 /* roll the gtk index. */ 554 wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1); 555 /* 556 * Save all connected devices on a list while holding wusbhc->mutex and 557 * take a reference to each one. Then submit the set key request to 558 * them after releasing the lock in order to avoid a deadlock. 559 */ 560 for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) { 561 wusb_dev = wusbhc->port[port_idx].wusb_dev; 562 if (!wusb_dev || !wusb_dev->usb_dev 563 || !wusb_dev->usb_dev->authenticated) 564 continue; 565 566 wusb_dev_get(wusb_dev); 567 list_add_tail(&wusb_dev->rekey_node, &rekey_list); 568 } 569 mutex_unlock(&wusbhc->mutex); 570 571 /* Submit the rekey requests without holding wusbhc->mutex. */ 572 list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list, 573 rekey_node) { 574 list_del_init(&wusb_dev->rekey_node); 575 dev_dbg(&wusb_dev->usb_dev->dev, 576 "%s: rekey device at port %d\n", 577 __func__, wusb_dev->port_idx); 578 579 if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) { 580 dev_err(&wusb_dev->usb_dev->dev, 581 "%s: rekey device at port %d failed\n", 582 __func__, wusb_dev->port_idx); 583 } 584 wusb_dev_put(wusb_dev); 585 } 586 587 /* Switch the host controller to use the new GTK. */ 588 mutex_lock(&wusbhc->mutex); 589 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, 590 &wusbhc->gtk.descr.bKeyData, key_size); 591 mutex_unlock(&wusbhc->mutex); 592} 593 594/** 595 * wusbhc_gtk_rekey - generate and distribute a new GTK 596 * @wusbhc: the WUSB host controller 597 * 598 * Generate a new GTK and distribute it to all connected and 599 * authenticated devices. When all devices have the new GTK, the host 600 * starts using it. 601 * 602 * This must be called after every device disconnect (see [WUSB] 603 * section 6.2.11.2). 604 */ 605void wusbhc_gtk_rekey(struct wusbhc *wusbhc) 606{ 607 /* 608 * We need to submit a URB to the downstream WUSB devices in order to 609 * change the group key. This can't be done while holding the 610 * wusbhc->mutex since that is also taken in the urb_enqueue routine 611 * and will cause a deadlock. Instead, queue a work item to do 612 * it when the lock is not held 613 */ 614 queue_work(wusbhc->wq_security, &wusbhc->gtk_rekey_work); 615} 616