// SPDX-License-Identifier: GPL-2.0 /* * Wireless USB Host Controller * Security support: encryption enablement, etc * * Copyright (C) 2006 Intel Corporation * Inaky Perez-Gonzalez * * FIXME: docs */ #include #include #include #include #include #include "wusbhc.h" #include static void wusbhc_gtk_rekey_work(struct work_struct *work); int wusbhc_sec_create(struct wusbhc *wusbhc) { /* * WQ is singlethread because we need to serialize rekey operations. * Use a separate workqueue for security operations instead of the * wusbd workqueue because security operations may need to communicate * directly with downstream wireless devices using synchronous URBs. * If a device is not responding, this could block other host * controller operations. */ wusbhc->wq_security = create_singlethread_workqueue("wusbd_security"); if (wusbhc->wq_security == NULL) { pr_err("WUSB-core: Cannot create wusbd_security workqueue\n"); return -ENOMEM; } 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 = 0; INIT_WORK(&wusbhc->gtk_rekey_work, wusbhc_gtk_rekey_work); return 0; } /* Called when the HC is destroyed */ void wusbhc_sec_destroy(struct wusbhc *wusbhc) { destroy_workqueue(wusbhc->wq_security); } /** * 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 consists of two parts: the device's authenticated * 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_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, USB_CTRL_SET_TIMEOUT); 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; u8 key_index = wusb_key_index(wusbhc->gtk_index, WUSB_KEY_INDEX_TYPE_GTK, WUSB_KEY_INDEX_ORIGINATOR_HOST); 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 | key_index, 0, &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength, USB_CTRL_SET_TIMEOUT); } /* 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, *new_secd; const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL; const void *itr, *top; char buf[64]; secd = kmalloc(sizeof(*secd), GFP_KERNEL); if (secd == NULL) { result = -ENOMEM; goto out; } 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 out; } secd_size = le16_to_cpu(secd->wTotalLength); new_secd = krealloc(secd, secd_size, GFP_KERNEL); if (new_secd == NULL) { dev_err(dev, "Can't allocate space for security descriptors\n"); result = -ENOMEM; goto out; } secd = new_secd; result = usb_get_descriptor(usb_dev, USB_DT_SECURITY, 0, secd, secd_size); if (result < secd_size) { dev_err(dev, "Can't read security descriptor or " "not enough data: %d\n", result); goto out; } bytes = 0; itr = &secd[1]; top = (void *)secd + 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 out; } wusb_dev->ccm1_etd = *ccm1_etd; dev_dbg(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; out: kfree(secd); return result; } void wusb_dev_sec_rm(struct wusb_dev *wusb_dev) { /* Nothing so far */ } /** * 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. */ 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, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); 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_set_device_state(usb_dev, USB_STATE_DEFAULT); usb_ep0_reinit(usb_dev); /* Set new (authenticated) address. */ result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0), USB_REQ_SET_ADDRESS, USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE, new_address, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); 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_set_device_state(usb_dev, USB_STATE_ADDRESS); 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; 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 = kcalloc(3, sizeof(hs[0]), GFP_KERNEL); if (!hs) 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); hs[0].bMessageNumber = 1; hs[0].bStatus = 0; put_unaligned_le32(tkid, 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] */ 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]), USB_CTRL_SET_TIMEOUT); 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]), USB_CTRL_GET_TIMEOUT); if (result < 0) { dev_err(dev, "Handshake2: request failed: %d\n", result); goto error_hs2; } 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] */ put_unaligned_le32(tkid, 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; } /* 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; } 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; put_unaligned_le32(tkid, 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; } 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]), USB_CTRL_SET_TIMEOUT); if (result < 0) { dev_err(dev, "Handshake3: request failed: %d\n", result); goto error_hs3; } 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; 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) { result = wusb_dev_update_address(wusbhc, wusb_dev); if (result < 0) goto error_dev_update_address; } result = 0; dev_info(dev, "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])); memzero_explicit(&keydvt_out, sizeof(keydvt_out)); memzero_explicit(&keydvt_in, sizeof(keydvt_in)); memzero_explicit(&ccm_n, sizeof(ccm_n)); memzero_explicit(mic, sizeof(mic)); if (result < 0) 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_work(struct work_struct *work) { struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_work); size_t key_size = sizeof(wusbhc->gtk.data); int port_idx; struct wusb_dev *wusb_dev, *wusb_dev_next; LIST_HEAD(rekey_list); mutex_lock(&wusbhc->mutex); /* generate the new key */ wusbhc_generate_gtk(wusbhc); /* roll the gtk index. */ wusbhc->gtk_index = (wusbhc->gtk_index + 1) % (WUSB_KEY_INDEX_MAX + 1); /* * Save all connected devices on a list while holding wusbhc->mutex and * take a reference to each one. Then submit the set key request to * them after releasing the lock in order to avoid a deadlock. */ for (port_idx = 0; port_idx < wusbhc->ports_max; port_idx++) { wusb_dev = wusbhc->port[port_idx].wusb_dev; if (!wusb_dev || !wusb_dev->usb_dev || !wusb_dev->usb_dev->authenticated) continue; wusb_dev_get(wusb_dev); list_add_tail(&wusb_dev->rekey_node, &rekey_list); } mutex_unlock(&wusbhc->mutex); /* Submit the rekey requests without holding wusbhc->mutex. */ list_for_each_entry_safe(wusb_dev, wusb_dev_next, &rekey_list, rekey_node) { list_del_init(&wusb_dev->rekey_node); dev_dbg(&wusb_dev->usb_dev->dev, "%s: rekey device at port %d\n", __func__, wusb_dev->port_idx); if (wusb_dev_set_gtk(wusbhc, wusb_dev) < 0) { dev_err(&wusb_dev->usb_dev->dev, "%s: rekey device at port %d failed\n", __func__, wusb_dev->port_idx); } wusb_dev_put(wusb_dev); } /* Switch the host controller to use the new GTK. */ mutex_lock(&wusbhc->mutex); wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size); mutex_unlock(&wusbhc->mutex); } /** * 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) { /* * We need to submit a URB to the downstream WUSB devices in order to * change the group key. This can't be done while holding the * wusbhc->mutex since that is also taken in the urb_enqueue routine * and will cause a deadlock. Instead, queue a work item to do * it when the lock is not held */ queue_work(wusbhc->wq_security, &wusbhc->gtk_rekey_work); }