/* * Wireless USB Host Controller * Security support: encryption enablement, etc * * Copyright (C) 2006 Intel Corporation * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. * * * FIXME: docs */ #include <linux/types.h> #include <linux/usb/ch9.h> #include <linux/random.h> #include "wusbhc.h" /* * DEBUG & SECURITY WARNING!!!! * * If you enable this past 1, the debug code will weaken the * cryptographic safety of the system (on purpose, for debugging). * * Weaken means: * we print secret keys and intermediate values all the way, */ #undef D_LOCAL #define D_LOCAL 2 #include <linux/uwb/debug.h> static void wusbhc_set_gtk_callback(struct urb *urb); static void wusbhc_gtk_rekey_done_work(struct work_struct *work); int wusbhc_sec_create(struct wusbhc *wusbhc) { wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data); wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY; wusbhc->gtk.descr.bReserved = 0; wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST); INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work); return 0; } /* Called when the HC is destroyed */ void wusbhc_sec_destroy(struct wusbhc *wusbhc) { } /** * wusbhc_next_tkid - generate a new, currently unused, TKID * @wusbhc: the WUSB host controller * @wusb_dev: the device whose PTK the TKID is for * (or NULL for a TKID for a GTK) * * The generated TKID consist of two parts: the device's authenicated * address (or 0 or a GTK); and an incrementing number. This ensures * that TKIDs cannot be shared between devices and by the time the * incrementing number wraps around the older TKIDs will no longer be * in use (a maximum of two keys may be active at any one time). */ static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) { u32 *tkid; u32 addr; if (wusb_dev == NULL) { tkid = &wusbhc->gtk_tkid; addr = 0; } else { tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid; addr = wusb_dev->addr & 0x7f; } *tkid = (addr << 8) | ((*tkid + 1) & 0xff); return *tkid; } static void wusbhc_generate_gtk(struct wusbhc *wusbhc) { const size_t key_size = sizeof(wusbhc->gtk.data); u32 tkid; tkid = wusbhc_next_tkid(wusbhc, NULL); wusbhc->gtk.descr.tTKID[0] = (tkid >> 0) & 0xff; wusbhc->gtk.descr.tTKID[1] = (tkid >> 8) & 0xff; wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff; get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size); } /** * wusbhc_sec_start - start the security management process * @wusbhc: the WUSB host controller * * Generate and set an initial GTK on the host controller. * * Called when the HC is started. */ int wusbhc_sec_start(struct wusbhc *wusbhc) { const size_t key_size = sizeof(wusbhc->gtk.data); int result; wusbhc_generate_gtk(wusbhc); result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size); if (result < 0) dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n", result); return result; } /** * wusbhc_sec_stop - stop the security management process * @wusbhc: the WUSB host controller * * Wait for any pending GTK rekeys to stop. */ void wusbhc_sec_stop(struct wusbhc *wusbhc) { cancel_work_sync(&wusbhc->gtk_rekey_done_work); } /** @returns encryption type name */ const char *wusb_et_name(u8 x) { switch (x) { case USB_ENC_TYPE_UNSECURE: return "unsecure"; case USB_ENC_TYPE_WIRED: return "wired"; case USB_ENC_TYPE_CCM_1: return "CCM-1"; case USB_ENC_TYPE_RSA_1: return "RSA-1"; default: return "unknown"; } } EXPORT_SYMBOL_GPL(wusb_et_name); /* * Set the device encryption method * * We tell the device which encryption method to use; we do this when * setting up the device's security. */ static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value) { int result; struct device *dev = &usb_dev->dev; struct wusb_dev *wusb_dev = usb_dev->wusb_dev; if (value) { value = wusb_dev->ccm1_etd.bEncryptionValue; } else { /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */ value = 0; } /* Set device's */ result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_ENCRYPTION, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, value, 0, NULL, 0, 1000 /* FIXME: arbitrary */); if (result < 0) dev_err(dev, "Can't set device's WUSB encryption to " "%s (value %d): %d\n", wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType), wusb_dev->ccm1_etd.bEncryptionValue, result); return result; } /* * Set the GTK to be used by a device. * * The device must be authenticated. */ static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) { struct usb_device *usb_dev = wusb_dev->usb_dev; return usb_control_msg( usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_DESCRIPTOR, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, USB_DT_KEY << 8 | wusbhc->gtk_index, 0, &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength, 1000); } /* FIXME: prototype for adding security */ int wusb_dev_sec_add(struct wusbhc *wusbhc, struct usb_device *usb_dev, struct wusb_dev *wusb_dev) { int result, bytes, secd_size; struct device *dev = &usb_dev->dev; struct usb_security_descriptor secd; const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL; void *secd_buf; const void *itr, *top; char buf[64]; d_fnstart(3, dev, "(usb_dev %p, wusb_dev %p)\n", usb_dev, wusb_dev); result = usb_get_descriptor(usb_dev, USB_DT_SECURITY, 0, &secd, sizeof(secd)); if (result < sizeof(secd)) { dev_err(dev, "Can't read security descriptor or " "not enough data: %d\n", result); goto error_secd; } secd_size = le16_to_cpu(secd.wTotalLength); d_printf(5, dev, "got %d bytes of sec descriptor, total is %d\n", result, secd_size); secd_buf = kmalloc(secd_size, GFP_KERNEL); if (secd_buf == NULL) { dev_err(dev, "Can't allocate space for security descriptors\n"); goto error_secd_alloc; } result = usb_get_descriptor(usb_dev, USB_DT_SECURITY, 0, secd_buf, secd_size); if (result < secd_size) { dev_err(dev, "Can't read security descriptor or " "not enough data: %d\n", result); goto error_secd_all; } d_printf(5, dev, "got %d bytes of sec descriptors\n", result); bytes = 0; itr = secd_buf + sizeof(secd); top = secd_buf + result; while (itr < top) { etd = itr; if (top - itr < sizeof(*etd)) { dev_err(dev, "BUG: bad device security descriptor; " "not enough data (%zu vs %zu bytes left)\n", top - itr, sizeof(*etd)); break; } if (etd->bLength < sizeof(*etd)) { dev_err(dev, "BUG: bad device encryption descriptor; " "descriptor is too short " "(%u vs %zu needed)\n", etd->bLength, sizeof(*etd)); break; } itr += etd->bLength; bytes += snprintf(buf + bytes, sizeof(buf) - bytes, "%s (0x%02x/%02x) ", wusb_et_name(etd->bEncryptionType), etd->bEncryptionValue, etd->bAuthKeyIndex); if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1) ccm1_etd = etd; } /* This code only supports CCM1 as of now. */ /* FIXME: user has to choose which sec mode to use? * In theory we want CCM */ if (ccm1_etd == NULL) { dev_err(dev, "WUSB device doesn't support CCM1 encryption, " "can't use!\n"); result = -EINVAL; goto error_no_ccm1; } wusb_dev->ccm1_etd = *ccm1_etd; dev_info(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n", buf, wusb_et_name(ccm1_etd->bEncryptionType), ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex); result = 0; kfree(secd_buf); out: d_fnend(3, dev, "(usb_dev %p, wusb_dev %p) = %d\n", usb_dev, wusb_dev, result); return result; error_no_ccm1: error_secd_all: kfree(secd_buf); error_secd_alloc: error_secd: goto out; } void wusb_dev_sec_rm(struct wusb_dev *wusb_dev) { /* Nothing so far */ } static void hs_printk(unsigned level, struct device *dev, struct usb_handshake *hs) { d_printf(level, dev, " bMessageNumber: %u\n" " bStatus: %u\n" " tTKID: %02x %02x %02x\n" " CDID: %02x %02x %02x %02x %02x %02x %02x %02x\n" " %02x %02x %02x %02x %02x %02x %02x %02x\n" " nonce: %02x %02x %02x %02x %02x %02x %02x %02x\n" " %02x %02x %02x %02x %02x %02x %02x %02x\n" " MIC: %02x %02x %02x %02x %02x %02x %02x %02x\n", hs->bMessageNumber, hs->bStatus, hs->tTKID[2], hs->tTKID[1], hs->tTKID[0], hs->CDID[0], hs->CDID[1], hs->CDID[2], hs->CDID[3], hs->CDID[4], hs->CDID[5], hs->CDID[6], hs->CDID[7], hs->CDID[8], hs->CDID[9], hs->CDID[10], hs->CDID[11], hs->CDID[12], hs->CDID[13], hs->CDID[14], hs->CDID[15], hs->nonce[0], hs->nonce[1], hs->nonce[2], hs->nonce[3], hs->nonce[4], hs->nonce[5], hs->nonce[6], hs->nonce[7], hs->nonce[8], hs->nonce[9], hs->nonce[10], hs->nonce[11], hs->nonce[12], hs->nonce[13], hs->nonce[14], hs->nonce[15], hs->MIC[0], hs->MIC[1], hs->MIC[2], hs->MIC[3], hs->MIC[4], hs->MIC[5], hs->MIC[6], hs->MIC[7]); } /** * Update the address of an unauthenticated WUSB device * * Once we have successfully authenticated, we take it to addr0 state * and then to a normal address. * * Before the device's address (as known by it) was usb_dev->devnum | * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum. */ static int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev) { int result = -ENOMEM; struct usb_device *usb_dev = wusb_dev->usb_dev; struct device *dev = &usb_dev->dev; u8 new_address = wusb_dev->addr & 0x7F; /* Set address 0 */ result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_ADDRESS, 0, 0, 0, NULL, 0, 1000 /* FIXME: arbitrary */); if (result < 0) { dev_err(dev, "auth failed: can't set address 0: %d\n", result); goto error_addr0; } result = wusb_set_dev_addr(wusbhc, wusb_dev, 0); if (result < 0) goto error_addr0; usb_ep0_reinit(usb_dev); /* Set new (authenticated) address. */ result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_ADDRESS, 0, new_address, 0, NULL, 0, 1000 /* FIXME: arbitrary */); if (result < 0) { dev_err(dev, "auth failed: can't set address %u: %d\n", new_address, result); goto error_addr; } result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address); if (result < 0) goto error_addr; usb_ep0_reinit(usb_dev); usb_dev->authenticated = 1; error_addr: error_addr0: return result; } /* * * */ /* FIXME: split and cleanup */ int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev, struct wusb_ckhdid *ck) { int result = -ENOMEM; struct usb_device *usb_dev = wusb_dev->usb_dev; struct device *dev = &usb_dev->dev; u32 tkid; __le32 tkid_le; struct usb_handshake *hs; struct aes_ccm_nonce ccm_n; u8 mic[8]; struct wusb_keydvt_in keydvt_in; struct wusb_keydvt_out keydvt_out; hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL); if (hs == NULL) { dev_err(dev, "can't allocate handshake data\n"); goto error_kzalloc; } /* We need to turn encryption before beginning the 4way * hshake (WUSB1.0[.3.2.2]) */ result = wusb_dev_set_encryption(usb_dev, 1); if (result < 0) goto error_dev_set_encryption; tkid = wusbhc_next_tkid(wusbhc, wusb_dev); tkid_le = cpu_to_le32(tkid); hs[0].bMessageNumber = 1; hs[0].bStatus = 0; memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID)); hs[0].bReserved = 0; memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID)); get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce)); memset(hs[0].MIC, 0, sizeof(hs[0].MIC)); /* Per WUSB1.0[T7-22] */ d_printf(1, dev, "I: sending hs1:\n"); hs_printk(2, dev, &hs[0]); result = usb_control_msg( usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_HANDSHAKE, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */); if (result < 0) { dev_err(dev, "Handshake1: request failed: %d\n", result); goto error_hs1; } /* Handshake 2, from the device -- need to verify fields */ result = usb_control_msg( usb_dev, usb_rcvctrlpipe(usb_dev, 0), USB_REQ_GET_HANDSHAKE, USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */); if (result < 0) { dev_err(dev, "Handshake2: request failed: %d\n", result); goto error_hs2; } d_printf(1, dev, "got HS2:\n"); hs_printk(2, dev, &hs[1]); result = -EINVAL; if (hs[1].bMessageNumber != 2) { dev_err(dev, "Handshake2 failed: bad message number %u\n", hs[1].bMessageNumber); goto error_hs2; } if (hs[1].bStatus != 0) { dev_err(dev, "Handshake2 failed: bad status %u\n", hs[1].bStatus); goto error_hs2; } if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) { dev_err(dev, "Handshake2 failed: TKID mismatch " "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n", hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2], hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]); goto error_hs2; } if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) { dev_err(dev, "Handshake2 failed: CDID mismatch\n"); goto error_hs2; } /* Setup the CCM nonce */ memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn)); /* Per WUSB1.0[6.5.2] */ memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid)); ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr; ccm_n.dest_addr.data[0] = wusb_dev->addr; ccm_n.dest_addr.data[1] = 0; /* Derive the KCK and PTK from CK, the CCM, H and D nonces */ memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce)); memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce)); result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in); if (result < 0) { dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n", result); goto error_hs2; } d_printf(2, dev, "KCK:\n"); d_dump(2, dev, keydvt_out.kck, sizeof(keydvt_out.kck)); d_printf(2, dev, "PTK:\n"); d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk)); /* Compute MIC and verify it */ result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]); if (result < 0) { dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n", result); goto error_hs2; } d_printf(2, dev, "MIC:\n"); d_dump(2, dev, mic, sizeof(mic)); if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) { dev_err(dev, "Handshake2 failed: MIC mismatch\n"); goto error_hs2; } /* Send Handshake3 */ hs[2].bMessageNumber = 3; hs[2].bStatus = 0; memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID)); hs[2].bReserved = 0; memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID)); memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce)); result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]); if (result < 0) { dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n", result); goto error_hs2; } d_printf(1, dev, "I: sending hs3:\n"); hs_printk(2, dev, &hs[2]); result = usb_control_msg( usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_HANDSHAKE, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */); if (result < 0) { dev_err(dev, "Handshake3: request failed: %d\n", result); goto error_hs3; } d_printf(1, dev, "I: turning on encryption on host for device\n"); d_dump(2, dev, keydvt_out.ptk, sizeof(keydvt_out.ptk)); result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid, keydvt_out.ptk, sizeof(keydvt_out.ptk)); if (result < 0) goto error_wusbhc_set_ptk; d_printf(1, dev, "I: setting a GTK\n"); result = wusb_dev_set_gtk(wusbhc, wusb_dev); if (result < 0) { dev_err(dev, "Set GTK for device: request failed: %d\n", result); goto error_wusbhc_set_gtk; } /* Update the device's address from unauth to auth */ if (usb_dev->authenticated == 0) { d_printf(1, dev, "I: updating addres to auth from non-auth\n"); result = wusb_dev_update_address(wusbhc, wusb_dev); if (result < 0) goto error_dev_update_address; } result = 0; d_printf(1, dev, "I: 4way handshke done, device authenticated\n"); error_dev_update_address: error_wusbhc_set_gtk: error_wusbhc_set_ptk: error_hs3: error_hs2: error_hs1: memset(hs, 0, 3*sizeof(hs[0])); memset(&keydvt_out, 0, sizeof(keydvt_out)); memset(&keydvt_in, 0, sizeof(keydvt_in)); memset(&ccm_n, 0, sizeof(ccm_n)); memset(mic, 0, sizeof(mic)); if (result < 0) { /* error path */ wusb_dev_set_encryption(usb_dev, 0); } error_dev_set_encryption: kfree(hs); error_kzalloc: return result; } /* * Once all connected and authenticated devices have received the new * GTK, switch the host to using it. */ static void wusbhc_gtk_rekey_done_work(struct work_struct *work) { struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work); size_t key_size = sizeof(wusbhc->gtk.data); mutex_lock(&wusbhc->mutex); if (--wusbhc->pending_set_gtks == 0) wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size); mutex_unlock(&wusbhc->mutex); } static void wusbhc_set_gtk_callback(struct urb *urb) { struct wusbhc *wusbhc = urb->context; queue_work(wusbd, &wusbhc->gtk_rekey_done_work); } /** * wusbhc_gtk_rekey - generate and distribute a new GTK * @wusbhc: the WUSB host controller * * Generate a new GTK and distribute it to all connected and * authenticated devices. When all devices have the new GTK, the host * starts using it. * * This must be called after every device disconnect (see [WUSB] * section 6.2.11.2). */ void wusbhc_gtk_rekey(struct wusbhc *wusbhc) { static const size_t key_size = sizeof(wusbhc->gtk.data); int p; wusbhc_generate_gtk(wusbhc); for (p = 0; p < wusbhc->ports_max; p++) { struct wusb_dev *wusb_dev; wusb_dev = wusbhc->port[p].wusb_dev; if (!wusb_dev || !wusb_dev->usb_dev | !wusb_dev->usb_dev->authenticated) continue; usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev, usb_sndctrlpipe(wusb_dev->usb_dev, 0), (void *)wusb_dev->set_gtk_req, &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength, wusbhc_set_gtk_callback, wusbhc); if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0) wusbhc->pending_set_gtks++; } if (wusbhc->pending_set_gtks == 0) wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size); }