linux/drivers/usb/wusbcore/security.c
David Vrabel 6da9c99059 USB: allow libusb to talk to unauthenticated WUSB devices
To permit a userspace application to associate with WUSB devices
using numeric association, control transfers to unauthenticated WUSB
devices must be allowed.

This requires that wusbcore correctly sets the device state to
UNAUTHENTICATED, DEFAULT and ADDRESS and that control transfers can be
performed to UNAUTHENTICATED devices.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:20:35 -07:00

579 lines
16 KiB
C

/*
* 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"
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];
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);
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;
}
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_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;
kfree(secd_buf);
out:
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 */
}
/**
* 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_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, 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_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 = 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] */
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;
}
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]), 1000 /* FIXME: arbitrary */);
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]));
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)
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);
}