diff options
Diffstat (limited to 'kernel/drivers/usb/wusbcore/security.c')
| -rw-r--r-- | kernel/drivers/usb/wusbcore/security.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/kernel/drivers/usb/wusbcore/security.c b/kernel/drivers/usb/wusbcore/security.c new file mode 100644 index 000000000..b66faaf3e --- /dev/null +++ b/kernel/drivers/usb/wusbcore/security.c @@ -0,0 +1,615 @@ +/* + * 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/slab.h> +#include <linux/usb/ch9.h> +#include <linux/random.h> +#include <linux/export.h> +#include "wusbhc.h" + +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"); + 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; + __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 = kcalloc(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] */ + + 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] */ + 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; + } + + /* 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; + 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; + } + + 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); +} |