kernel-hacking-2024-linux-s.../drivers/usb/wusbcore/cbaf.c
Inaky Perez-Gonzalez 870d539504 wusb: add the USB wusb-cbaf driver
Add a driver for cable based associated of (Wireless) USB devices.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
2008-09-17 16:54:30 +01:00

620 lines
20 KiB
C

/*
* Wireless USB - Cable Based Association
*
*
* 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.
*
*
* WUSB devices have to be paired (authenticated in WUSB lingo) so
* that they can connect to the system.
*
* One way of pairing is using CBA-Cable Based Authentication, devices
* that can connect via wired or wireless USB. First time you plug
* them with a cable, pairing is done between host and device and
* subsequent times, you can connect wirelessly without having to
* pair. That's the idea.
*
* This driver does nothing Earth shattering. It just provides an
* interface to chat with the wire-connected device so we can get a
* CDID (device ID) that might have been previously associated to a
* CHID (host ID) and to set up a new <CHID,CDID,CK> triplet
* (connection context), with the CK being the secret, or connection
* key. This is the pairing data.
*
* When a device with the CBA capability connects, the probe routine
* just creates a bunch of sysfs files that a user space enumeration
* manager uses to allow it to connect wirelessly to the system or not.
*
* The process goes like this:
*
* 1. device plugs, cbaf is loaded, notifications happen
*
* 2. the connection manager sees a device with CBAF capability (the
* wusb_{host_info,cdid,cc} files are in /sys/device/blah/OURDEVICE).
*
* 3. CM (connection manager) writes the CHID (host ID) and a host
* name into the wusb_host_info file. This gets sent to the device.
*
* 4. CM cats the wusb_cdid file; this asks the device if it has any
* CDID associated to the CHDI we just wrote before. If it does, it
* is printed, along with the device 'friendly name' and the band
* groups the device supports.
*
* 5. CM looks up its database
*
* 5.1 If it has a matching CHID,CDID entry, the device has been
* authorized before (paired). Now we can optionally ask the user
* if he wants to allow the device to connect. Then we generate a
* new CDID and CK, send it to the device and update the database
* (writing to the wusb_cc file so they are uploaded to the device).
*
* 5.2 If the CDID is zero (or we didn't find a matching CDID in our
* database), we assume the device is not known. We ask the user
* if s/he wants to allow the device to be connected wirelessly
* to the system. If nope, nothing else is done (FIXME: maybe
* send a zero CDID to clean up our CHID?). If yes, we generate
* random CDID and CKs (and write them to the wusb_cc file so
* they are uploaded to the device).
*
* 6. device is unplugged
*
* When the device tries to connect wirelessly, it will present it's
* CDID to the WUSB host controller with ID CHID, which will query the
* database. If found, the host will (with a 4way handshake) challenge
* the device to demonstrate it has the CK secret key (from our
* database) without actually exchanging it. Once satisfied, crypto
* keys are derived from the CK, the device is connected and all
* communication is crypted.
*
*
* NOTES ABOUT THE IMPLEMENTATION
*
* The descriptors sent back and forth use this horrible format from
* hell on which each field is actually a field ID, field length and
* then the field itself. How stupid can that get, taking into account
* the structures are defined by the spec?? oh well.
*
*
* FIXME: we don't provide a way to tell the device the pairing failed
* (ie: send a CC_DATA_FAIL). Should add some day.
*/
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/version.h>
#include <linux/usb.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/random.h>
#include <linux/mutex.h>
#include <linux/uwb.h>
#include <linux/usb/wusb.h>
#include <linux/usb/association.h>
#undef D_LOCAL
#define D_LOCAL 6
#include <linux/uwb/debug.h>
/* An instance of a Cable-Based-Association-Framework device */
struct cbaf {
struct usb_device *usb_dev;
struct usb_interface *usb_iface;
void *buffer;
size_t buffer_size;
struct wusb_ckhdid chid;/* Host Information */
char host_name[65]; /* max length:
Assoc Models Suplement 1.0[T4-7] */
u16 host_band_groups;
struct wusb_ckhdid cdid;/* Device Information */
char device_name[65]; /* max length:
Assoc Models Suplement 1.0[T4-7] */
u16 device_band_groups;
struct wusb_ckhdid ck; /* Connection Key */
};
/*
* Verify that a CBAF USB-interface has what we need
*
* (like we care, we are going to fail the enumeration if not :)
*
* FIXME: ugly function, need to split
*/
static int cbaf_check(struct cbaf *cbaf)
{
int result;
struct device *dev = &cbaf->usb_iface->dev;
struct wusb_cbaf_assoc_info *assoc_info;
struct wusb_cbaf_assoc_request *assoc_request;
size_t assoc_size;
void *itr, *top;
unsigned ar_index;
int ar_rhi_idx = -1, ar_assoc_idx = -1;
result = usb_control_msg(
cbaf->usb_dev, usb_rcvctrlpipe(cbaf->usb_dev, 0),
CBAF_REQ_GET_ASSOCIATION_INFORMATION,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0, cbaf->usb_iface->cur_altsetting->desc.bInterfaceNumber,
cbaf->buffer, cbaf->buffer_size, 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "cannot get available association types: %d\n",
result);
goto error_get_assoc_types;
}
assoc_info = cbaf->buffer;
if (result < sizeof(*assoc_info)) {
dev_err(dev, "not enough data to decode association info "
"header (%zu vs %zu bytes required)\n",
(size_t)result, sizeof(*assoc_info));
goto error_bad_header;
}
assoc_size = le16_to_cpu(assoc_info->Length);
if (result < assoc_size) {
dev_err(dev, "not enough data to decode association info "
"(%zu vs %zu bytes required)\n",
(size_t)assoc_size, sizeof(*assoc_info));
goto error_bad_data;
}
/*
* From now on, we just verify, but won't error out unless we
* don't find the AR_TYPE_WUSB_{RETRIEVE_HOST_INFO,ASSOCIATE}
* types.
*/
ar_index = 0;
itr = cbaf->buffer + sizeof(*assoc_info);
top = cbaf->buffer + assoc_size;
d_printf(1, dev, "Found %u association requests (%zu bytes)\n",
assoc_info->NumAssociationRequests, assoc_size);
while (itr < top) {
u16 ar_type, ar_subtype;
u32 ar_size;
const char *ar_name;
assoc_request = itr;
if (top - itr < sizeof(*assoc_request)) {
dev_err(dev, "not enough data to decode associaton "
"request (%zu vs %zu bytes needed)\n",
top - itr, sizeof(*assoc_request));
break;
}
ar_type = le16_to_cpu(assoc_request->AssociationTypeId);
ar_subtype = le16_to_cpu(assoc_request->AssociationSubTypeId);
ar_size = le32_to_cpu(assoc_request->AssociationTypeInfoSize);
switch (ar_type) {
case AR_TYPE_WUSB:
/* Verify we have what is mandated by AMS1.0 */
switch (ar_subtype) {
case AR_TYPE_WUSB_RETRIEVE_HOST_INFO:
ar_name = "retrieve_host_info";
ar_rhi_idx = ar_index;
break;
case AR_TYPE_WUSB_ASSOCIATE:
/* send assoc data */
ar_name = "associate";
ar_assoc_idx = ar_index;
break;
default:
ar_name = "unknown";
};
break;
default:
ar_name = "unknown";
};
d_printf(1, dev, "association request #%02u: 0x%04x/%04x "
"(%zu bytes): %s\n",
assoc_request->AssociationDataIndex, ar_type,
ar_subtype, (size_t)ar_size, ar_name);
itr += sizeof(*assoc_request);
ar_index++;
}
if (ar_rhi_idx == -1) {
dev_err(dev, "Missing RETRIEVE_HOST_INFO association "
"request\n");
goto error_bad_reqs;
}
if (ar_assoc_idx == -1) {
dev_err(dev, "Missing ASSOCIATE association request\n");
goto error_bad_reqs;
}
return 0;
error_bad_header:
error_bad_data:
error_bad_reqs:
error_get_assoc_types:
return -EINVAL;
}
static const struct wusb_cbaf_host_info cbaf_host_info_defaults = {
.AssociationTypeId_hdr = WUSB_AR_AssociationTypeId,
.AssociationTypeId = cpu_to_le16(AR_TYPE_WUSB),
.AssociationSubTypeId_hdr = WUSB_AR_AssociationSubTypeId,
.AssociationSubTypeId = cpu_to_le16(AR_TYPE_WUSB_RETRIEVE_HOST_INFO),
.CHID_hdr = WUSB_AR_CHID,
.LangID_hdr = WUSB_AR_LangID,
.HostFriendlyName_hdr = WUSB_AR_HostFriendlyName,
};
/* Send WUSB host information (CHID and name) to a CBAF device */
static int cbaf_send_host_info(struct cbaf *cbaf)
{
struct wusb_cbaf_host_info *hi;
size_t hi_size;
hi = cbaf->buffer;
memset(hi, 0, sizeof(*hi));
*hi = cbaf_host_info_defaults;
hi->CHID = cbaf->chid;
hi->LangID = 0; /* FIXME: I guess... */
strncpy(hi->HostFriendlyName, cbaf->host_name,
hi->HostFriendlyName_hdr.len);
hi->HostFriendlyName_hdr.len =
cpu_to_le16(strlen(hi->HostFriendlyName));
hi_size = sizeof(*hi) + strlen(hi->HostFriendlyName);
return usb_control_msg(cbaf->usb_dev, usb_sndctrlpipe(cbaf->usb_dev, 0),
CBAF_REQ_SET_ASSOCIATION_RESPONSE,
USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0x0101,
cbaf->usb_iface->cur_altsetting->desc.bInterfaceNumber,
hi, hi_size, 1000 /* FIXME: arbitrary */);
}
/* Show current CHID info we have set from user space */
static ssize_t cbaf_wusb_host_info_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct usb_interface *iface = to_usb_interface(dev);
struct cbaf *cbaf = usb_get_intfdata(iface);
char pr_chid[WUSB_CKHDID_STRSIZE];
ckhdid_printf(pr_chid, sizeof(pr_chid), &cbaf->chid);
return scnprintf(buf, PAGE_SIZE, "CHID: %s\nName: %s\n",
pr_chid, cbaf->host_name);
}
/*
* Get a host info CHID from user space and send it to the device.
*
* The user can recover a CC from the device associated to that CHID
* by cat'ing wusb_connection_context.
*/
static ssize_t cbaf_wusb_host_info_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
ssize_t result;
struct usb_interface *iface = to_usb_interface(dev);
struct cbaf *cbaf = usb_get_intfdata(iface);
result = sscanf(buf,
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%04hx %64s\n",
&cbaf->chid.data[0] , &cbaf->chid.data[1],
&cbaf->chid.data[2] , &cbaf->chid.data[3],
&cbaf->chid.data[4] , &cbaf->chid.data[5],
&cbaf->chid.data[6] , &cbaf->chid.data[7],
&cbaf->chid.data[8] , &cbaf->chid.data[9],
&cbaf->chid.data[10], &cbaf->chid.data[11],
&cbaf->chid.data[12], &cbaf->chid.data[13],
&cbaf->chid.data[14], &cbaf->chid.data[15],
&cbaf->host_band_groups, cbaf->host_name);
if (result != 18) {
dev_err(dev, "Unrecognized CHID (need 16 8-bit hex digits, "
"a 16 bit hex band group mask "
"and a host name, got only %d)\n", (int)result);
return -EINVAL;
}
result = cbaf_send_host_info(cbaf);
if (result < 0)
dev_err(dev, "Couldn't send host information to device: %d\n",
(int)result);
else
d_printf(1, dev, "HI sent, wusb_cc can be read now\n");
return result < 0 ? result : size;
}
static DEVICE_ATTR(wusb_host_info, 0600, cbaf_wusb_host_info_show,
cbaf_wusb_host_info_store);
static const struct wusb_cbaf_device_info cbaf_device_info_defaults = {
.Length_hdr = WUSB_AR_Length,
.CDID_hdr = WUSB_AR_CDID,
.BandGroups_hdr = WUSB_AR_BandGroups,
.LangID_hdr = WUSB_AR_LangID,
.DeviceFriendlyName_hdr = WUSB_AR_DeviceFriendlyName,
};
/*
* Get device's information (CDID) associated to CHID
*
* The device will return it's information (CDID, name, bandgroups)
* associated to the CHID we have set before, or 0 CDID and default
* name and bandgroup if no CHID set or unknown.
*/
static int cbaf_cdid_get(struct cbaf *cbaf)
{
int result;
struct device *dev = &cbaf->usb_iface->dev;
struct wusb_cbaf_device_info *di;
size_t needed, dev_name_size;
di = cbaf->buffer;
result = usb_control_msg(
cbaf->usb_dev, usb_rcvctrlpipe(cbaf->usb_dev, 0),
CBAF_REQ_GET_ASSOCIATION_REQUEST,
USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0x0200, cbaf->usb_iface->cur_altsetting->desc.bInterfaceNumber,
di, cbaf->buffer_size, 1000 /* FIXME: arbitrary */);
if (result < 0) {
dev_err(dev, "Cannot request device information: %d\n", result);
goto error_req_di;
}
needed = result < sizeof(*di) ? sizeof(*di) : le32_to_cpu(di->Length);
if (result < needed) {
dev_err(dev, "Not enough data in DEVICE_INFO reply (%zu vs "
"%zu bytes needed)\n", (size_t)result, needed);
goto error_bad_di;
}
cbaf->cdid = di->CDID;
dev_name_size = le16_to_cpu(di->DeviceFriendlyName_hdr.len);
dev_name_size = dev_name_size > 65 - 1 ? 65 - 1 : dev_name_size;
memcpy(cbaf->device_name, di->DeviceFriendlyName, dev_name_size);
cbaf->device_name[dev_name_size] = 0;
cbaf->device_band_groups = le16_to_cpu(di->BandGroups);
result = 0;
error_req_di:
error_bad_di:
return result;
}
/*
* Get device information and print it to sysfs
*
* See cbaf_cdid_get()
*/
static ssize_t cbaf_wusb_cdid_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
ssize_t result;
struct usb_interface *iface = to_usb_interface(dev);
struct cbaf *cbaf = usb_get_intfdata(iface);
char pr_cdid[WUSB_CKHDID_STRSIZE];
result = cbaf_cdid_get(cbaf);
if (result < 0) {
dev_err(dev, "Cannot read device information: %d\n",
(int)result);
goto error_get_di;
}
ckhdid_printf(pr_cdid, sizeof(pr_cdid), &cbaf->cdid);
result = scnprintf(buf, PAGE_SIZE,
"CDID: %s\nName: %s\nBand_groups: 0x%04x\n",
pr_cdid, cbaf->device_name,
cbaf->device_band_groups);
error_get_di:
return result;
}
static DEVICE_ATTR(wusb_cdid, 0600, cbaf_wusb_cdid_show, NULL);
static const struct wusb_cbaf_cc_data cbaf_cc_data_defaults = {
.AssociationTypeId_hdr = WUSB_AR_AssociationTypeId,
.AssociationTypeId = cpu_to_le16(AR_TYPE_WUSB),
.AssociationSubTypeId_hdr = WUSB_AR_AssociationSubTypeId,
.AssociationSubTypeId = cpu_to_le16(AR_TYPE_WUSB_ASSOCIATE),
.Length_hdr = WUSB_AR_Length,
.Length = cpu_to_le32(sizeof(struct wusb_cbaf_cc_data)),
.ConnectionContext_hdr = WUSB_AR_ConnectionContext,
.BandGroups_hdr = WUSB_AR_BandGroups,
};
static const struct wusb_cbaf_cc_data_fail cbaf_cc_data_fail_defaults = {
.AssociationTypeId_hdr = WUSB_AR_AssociationTypeId,
.AssociationSubTypeId_hdr = WUSB_AR_AssociationSubTypeId,
.Length_hdr = WUSB_AR_Length,
.AssociationStatus_hdr = WUSB_AR_AssociationStatus,
};
/*
* Send a new CC to the device
*
* So we update the CK and send the whole thing to the device
*/
static int cbaf_cc_upload(struct cbaf *cbaf)
{
int result;
struct device *dev = &cbaf->usb_iface->dev;
struct wusb_cbaf_cc_data *ccd;
char pr_cdid[WUSB_CKHDID_STRSIZE];
ccd = cbaf->buffer;
*ccd = cbaf_cc_data_defaults;
ccd->CHID = cbaf->chid;
ccd->CDID = cbaf->cdid;
ccd->CK = cbaf->ck;
ccd->BandGroups = cpu_to_le16(cbaf->host_band_groups);
result = usb_control_msg(
cbaf->usb_dev, usb_sndctrlpipe(cbaf->usb_dev, 0),
CBAF_REQ_SET_ASSOCIATION_RESPONSE,
USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0x0201, cbaf->usb_iface->cur_altsetting->desc.bInterfaceNumber,
ccd, sizeof(*ccd), 1000 /* FIXME: arbitrary */);
d_printf(1, dev, "Uploaded CC:\n");
ckhdid_printf(pr_cdid, sizeof(pr_cdid), &ccd->CHID);
d_printf(1, dev, " CHID %s\n", pr_cdid);
ckhdid_printf(pr_cdid, sizeof(pr_cdid), &ccd->CDID);
d_printf(1, dev, " CDID %s\n", pr_cdid);
ckhdid_printf(pr_cdid, sizeof(pr_cdid), &ccd->CK);
d_printf(1, dev, " CK %s\n", pr_cdid);
d_printf(1, dev, " bandgroups 0x%04x\n", cbaf->host_band_groups);
return result;
}
/*
* Send a new CC to the device
*
* We take the CDID and CK from user space, the rest from the info we
* set with host_info.
*/
static ssize_t cbaf_wusb_cc_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
ssize_t result;
struct usb_interface *iface = to_usb_interface(dev);
struct cbaf *cbaf = usb_get_intfdata(iface);
result = sscanf(buf,
"CDID: %02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx\n"
"CK: %02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx "
"%02hhx %02hhx %02hhx %02hhx\n",
&cbaf->cdid.data[0] , &cbaf->cdid.data[1],
&cbaf->cdid.data[2] , &cbaf->cdid.data[3],
&cbaf->cdid.data[4] , &cbaf->cdid.data[5],
&cbaf->cdid.data[6] , &cbaf->cdid.data[7],
&cbaf->cdid.data[8] , &cbaf->cdid.data[9],
&cbaf->cdid.data[10], &cbaf->cdid.data[11],
&cbaf->cdid.data[12], &cbaf->cdid.data[13],
&cbaf->cdid.data[14], &cbaf->cdid.data[15],
&cbaf->ck.data[0] , &cbaf->ck.data[1],
&cbaf->ck.data[2] , &cbaf->ck.data[3],
&cbaf->ck.data[4] , &cbaf->ck.data[5],
&cbaf->ck.data[6] , &cbaf->ck.data[7],
&cbaf->ck.data[8] , &cbaf->ck.data[9],
&cbaf->ck.data[10], &cbaf->ck.data[11],
&cbaf->ck.data[12], &cbaf->ck.data[13],
&cbaf->ck.data[14], &cbaf->ck.data[15]);
if (result != 32) {
dev_err(dev, "Unrecognized CHID/CK (need 32 8-bit "
"hex digits, got only %d)\n", (int)result);
return -EINVAL;
}
result = cbaf_cc_upload(cbaf);
if (result < 0)
dev_err(dev, "Couldn't upload connection context: %d\n",
(int)result);
else
d_printf(1, dev, "Connection context uploaded\n");
return result < 0 ? result : size;
}
static DEVICE_ATTR(wusb_cc, 0600, NULL, cbaf_wusb_cc_store);
static struct attribute *cbaf_dev_attrs[] = {
&dev_attr_wusb_host_info.attr,
&dev_attr_wusb_cdid.attr,
&dev_attr_wusb_cc.attr,
NULL,
};
static struct attribute_group cbaf_dev_attr_group = {
.name = NULL, /* we want them in the same directory */
.attrs = cbaf_dev_attrs,
};
static int cbaf_probe(struct usb_interface *iface,
const struct usb_device_id *id)
{
int result;
struct cbaf *cbaf;
struct device *dev = &iface->dev;
result = -ENOMEM;
cbaf = kzalloc(sizeof(*cbaf), GFP_KERNEL);
if (cbaf == NULL) {
dev_err(dev, "Unable to allocate instance\n");
goto error_kzalloc;
}
cbaf->buffer = kmalloc(512, GFP_KERNEL);
if (cbaf->buffer == NULL)
goto error_kmalloc_buffer;
cbaf->buffer_size = 512;
cbaf->usb_dev = usb_get_dev(interface_to_usbdev(iface));
cbaf->usb_iface = usb_get_intf(iface);
result = cbaf_check(cbaf);
if (result < 0)
goto error_check;
result = sysfs_create_group(&dev->kobj, &cbaf_dev_attr_group);
if (result < 0) {
dev_err(dev, "Can't register sysfs attr group: %d\n", result);
goto error_create_group;
}
usb_set_intfdata(iface, cbaf);
d_printf(2, dev, "CBA attached\n");
return 0;
error_create_group:
error_check:
kfree(cbaf->buffer);
error_kmalloc_buffer:
kfree(cbaf);
error_kzalloc:
return result;
}
static void cbaf_disconnect(struct usb_interface *iface)
{
struct cbaf *cbaf = usb_get_intfdata(iface);
struct device *dev = &iface->dev;
sysfs_remove_group(&dev->kobj, &cbaf_dev_attr_group);
usb_set_intfdata(iface, NULL);
usb_put_intf(iface);
kfree(cbaf->buffer);
/* paranoia: clean up crypto keys */
memset(cbaf, 0, sizeof(*cbaf));
kfree(cbaf);
d_printf(1, dev, "CBA detached\n");
}
static struct usb_device_id cbaf_id_table[] = {
{ USB_INTERFACE_INFO(0xef, 0x03, 0x01), },
{ },
};
MODULE_DEVICE_TABLE(usb, cbaf_id_table);
static struct usb_driver cbaf_driver = {
.name = "wusb-cbaf",
.id_table = cbaf_id_table,
.probe = cbaf_probe,
.disconnect = cbaf_disconnect,
};
static int __init cbaf_driver_init(void)
{
return usb_register(&cbaf_driver);
}
module_init(cbaf_driver_init);
static void __exit cbaf_driver_exit(void)
{
usb_deregister(&cbaf_driver);
}
module_exit(cbaf_driver_exit);
MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
MODULE_DESCRIPTION("Wireless USB Cable Based Association");
MODULE_LICENSE("GPL");