/*
* 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.
*/
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);
}
