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linux-next/net/bluetooth/hci_sysfs.c
Marcel Holtmann a67e899cf3 Bluetooth: Fix issue with sysfs handling for connections
Due to a semantic changes in flush_workqueue() the current approach of
synchronizing the sysfs handling for connections doesn't work anymore. The
whole approach is actually fully broken and based on assumptions that are
no longer valid.

With the introduction of Simple Pairing support, the creation of low-level
ACL links got changed. This change invalidates the reason why in the past
two independent work queues have been used for adding/removing sysfs
devices. The adding of the actual sysfs device is now postponed until the
host controller successfully assigns an unique handle to that link. So
the real synchronization happens inside the controller and not the host.

The only left-over problem is that some internals of the sysfs device
handling are not initialized ahead of time. This leaves potential access
to invalid data and can cause various NULL pointer dereferences. To fix
this a new function makes sure that all sysfs details are initialized
when an connection attempt is made. The actual sysfs device is only
registered when the connection has been successfully established. To
avoid a race condition with the registration, the check if a device is
registered has been moved into the removal work.

As an extra protection two flush_work() calls are left in place to
make sure a previous add/del work has been completed first.

Based on a report by Marc Pignat <marc.pignat@hevs.ch>

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Tested-by: Justin P. Mattock <justinmattock@gmail.com>
Tested-by: Roger Quadros <ext-roger.quadros@nokia.com>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
2009-05-04 14:29:02 -07:00

466 lines
11 KiB
C

/* Bluetooth HCI driver model support. */
#include <linux/kernel.h>
#include <linux/init.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
struct class *bt_class = NULL;
EXPORT_SYMBOL_GPL(bt_class);
static struct workqueue_struct *bt_workq;
static inline char *link_typetostr(int type)
{
switch (type) {
case ACL_LINK:
return "ACL";
case SCO_LINK:
return "SCO";
case ESCO_LINK:
return "eSCO";
default:
return "UNKNOWN";
}
}
static ssize_t show_link_type(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_conn *conn = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", link_typetostr(conn->type));
}
static ssize_t show_link_address(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_conn *conn = dev_get_drvdata(dev);
bdaddr_t bdaddr;
baswap(&bdaddr, &conn->dst);
return sprintf(buf, "%s\n", batostr(&bdaddr));
}
static ssize_t show_link_features(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_conn *conn = dev_get_drvdata(dev);
return sprintf(buf, "0x%02x%02x%02x%02x%02x%02x%02x%02x\n",
conn->features[0], conn->features[1],
conn->features[2], conn->features[3],
conn->features[4], conn->features[5],
conn->features[6], conn->features[7]);
}
#define LINK_ATTR(_name,_mode,_show,_store) \
struct device_attribute link_attr_##_name = __ATTR(_name,_mode,_show,_store)
static LINK_ATTR(type, S_IRUGO, show_link_type, NULL);
static LINK_ATTR(address, S_IRUGO, show_link_address, NULL);
static LINK_ATTR(features, S_IRUGO, show_link_features, NULL);
static struct attribute *bt_link_attrs[] = {
&link_attr_type.attr,
&link_attr_address.attr,
&link_attr_features.attr,
NULL
};
static struct attribute_group bt_link_group = {
.attrs = bt_link_attrs,
};
static struct attribute_group *bt_link_groups[] = {
&bt_link_group,
NULL
};
static void bt_link_release(struct device *dev)
{
void *data = dev_get_drvdata(dev);
kfree(data);
}
static struct device_type bt_link = {
.name = "link",
.groups = bt_link_groups,
.release = bt_link_release,
};
static void add_conn(struct work_struct *work)
{
struct hci_conn *conn = container_of(work, struct hci_conn, work_add);
/* ensure previous del is complete */
flush_work(&conn->work_del);
if (device_add(&conn->dev) < 0) {
BT_ERR("Failed to register connection device");
return;
}
}
/*
* The rfcomm tty device will possibly retain even when conn
* is down, and sysfs doesn't support move zombie device,
* so we should move the device before conn device is destroyed.
*/
static int __match_tty(struct device *dev, void *data)
{
return !strncmp(dev_name(dev), "rfcomm", 6);
}
static void del_conn(struct work_struct *work)
{
struct hci_conn *conn = container_of(work, struct hci_conn, work_del);
struct hci_dev *hdev = conn->hdev;
/* ensure previous add is complete */
flush_work(&conn->work_add);
if (!device_is_registered(&conn->dev))
return;
while (1) {
struct device *dev;
dev = device_find_child(&conn->dev, NULL, __match_tty);
if (!dev)
break;
device_move(dev, NULL, DPM_ORDER_DEV_LAST);
put_device(dev);
}
device_del(&conn->dev);
put_device(&conn->dev);
hci_dev_put(hdev);
}
void hci_conn_init_sysfs(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
BT_DBG("conn %p", conn);
conn->dev.type = &bt_link;
conn->dev.class = bt_class;
conn->dev.parent = &hdev->dev;
dev_set_drvdata(&conn->dev, conn);
device_initialize(&conn->dev);
INIT_WORK(&conn->work_add, add_conn);
INIT_WORK(&conn->work_del, del_conn);
}
void hci_conn_add_sysfs(struct hci_conn *conn)
{
struct hci_dev *hdev = conn->hdev;
BT_DBG("conn %p", conn);
dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle);
queue_work(bt_workq, &conn->work_add);
}
void hci_conn_del_sysfs(struct hci_conn *conn)
{
BT_DBG("conn %p", conn);
queue_work(bt_workq, &conn->work_del);
}
static inline char *host_typetostr(int type)
{
switch (type) {
case HCI_VIRTUAL:
return "VIRTUAL";
case HCI_USB:
return "USB";
case HCI_PCCARD:
return "PCCARD";
case HCI_UART:
return "UART";
case HCI_RS232:
return "RS232";
case HCI_PCI:
return "PCI";
case HCI_SDIO:
return "SDIO";
default:
return "UNKNOWN";
}
}
static ssize_t show_type(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", host_typetostr(hdev->type));
}
static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
char name[249];
int i;
for (i = 0; i < 248; i++)
name[i] = hdev->dev_name[i];
name[248] = '\0';
return sprintf(buf, "%s\n", name);
}
static ssize_t show_class(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "0x%.2x%.2x%.2x\n",
hdev->dev_class[2], hdev->dev_class[1], hdev->dev_class[0]);
}
static ssize_t show_address(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
bdaddr_t bdaddr;
baswap(&bdaddr, &hdev->bdaddr);
return sprintf(buf, "%s\n", batostr(&bdaddr));
}
static ssize_t show_features(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "0x%02x%02x%02x%02x%02x%02x%02x%02x\n",
hdev->features[0], hdev->features[1],
hdev->features[2], hdev->features[3],
hdev->features[4], hdev->features[5],
hdev->features[6], hdev->features[7]);
}
static ssize_t show_manufacturer(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->manufacturer);
}
static ssize_t show_hci_version(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->hci_ver);
}
static ssize_t show_hci_revision(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->hci_rev);
}
static ssize_t show_inquiry_cache(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
struct inquiry_cache *cache = &hdev->inq_cache;
struct inquiry_entry *e;
int n = 0;
hci_dev_lock_bh(hdev);
for (e = cache->list; e; e = e->next) {
struct inquiry_data *data = &e->data;
bdaddr_t bdaddr;
baswap(&bdaddr, &data->bdaddr);
n += sprintf(buf + n, "%s %d %d %d 0x%.2x%.2x%.2x 0x%.4x %d %d %u\n",
batostr(&bdaddr),
data->pscan_rep_mode, data->pscan_period_mode,
data->pscan_mode, data->dev_class[2],
data->dev_class[1], data->dev_class[0],
__le16_to_cpu(data->clock_offset),
data->rssi, data->ssp_mode, e->timestamp);
}
hci_dev_unlock_bh(hdev);
return n;
}
static ssize_t show_idle_timeout(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->idle_timeout);
}
static ssize_t store_idle_timeout(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
char *ptr;
__u32 val;
val = simple_strtoul(buf, &ptr, 10);
if (ptr == buf)
return -EINVAL;
if (val != 0 && (val < 500 || val > 3600000))
return -EINVAL;
hdev->idle_timeout = val;
return count;
}
static ssize_t show_sniff_max_interval(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->sniff_max_interval);
}
static ssize_t store_sniff_max_interval(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
char *ptr;
__u16 val;
val = simple_strtoul(buf, &ptr, 10);
if (ptr == buf)
return -EINVAL;
if (val < 0x0002 || val > 0xFFFE || val % 2)
return -EINVAL;
if (val < hdev->sniff_min_interval)
return -EINVAL;
hdev->sniff_max_interval = val;
return count;
}
static ssize_t show_sniff_min_interval(struct device *dev, struct device_attribute *attr, char *buf)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", hdev->sniff_min_interval);
}
static ssize_t store_sniff_min_interval(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct hci_dev *hdev = dev_get_drvdata(dev);
char *ptr;
__u16 val;
val = simple_strtoul(buf, &ptr, 10);
if (ptr == buf)
return -EINVAL;
if (val < 0x0002 || val > 0xFFFE || val % 2)
return -EINVAL;
if (val > hdev->sniff_max_interval)
return -EINVAL;
hdev->sniff_min_interval = val;
return count;
}
static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
static DEVICE_ATTR(class, S_IRUGO, show_class, NULL);
static DEVICE_ATTR(address, S_IRUGO, show_address, NULL);
static DEVICE_ATTR(features, S_IRUGO, show_features, NULL);
static DEVICE_ATTR(manufacturer, S_IRUGO, show_manufacturer, NULL);
static DEVICE_ATTR(hci_version, S_IRUGO, show_hci_version, NULL);
static DEVICE_ATTR(hci_revision, S_IRUGO, show_hci_revision, NULL);
static DEVICE_ATTR(inquiry_cache, S_IRUGO, show_inquiry_cache, NULL);
static DEVICE_ATTR(idle_timeout, S_IRUGO | S_IWUSR,
show_idle_timeout, store_idle_timeout);
static DEVICE_ATTR(sniff_max_interval, S_IRUGO | S_IWUSR,
show_sniff_max_interval, store_sniff_max_interval);
static DEVICE_ATTR(sniff_min_interval, S_IRUGO | S_IWUSR,
show_sniff_min_interval, store_sniff_min_interval);
static struct attribute *bt_host_attrs[] = {
&dev_attr_type.attr,
&dev_attr_name.attr,
&dev_attr_class.attr,
&dev_attr_address.attr,
&dev_attr_features.attr,
&dev_attr_manufacturer.attr,
&dev_attr_hci_version.attr,
&dev_attr_hci_revision.attr,
&dev_attr_inquiry_cache.attr,
&dev_attr_idle_timeout.attr,
&dev_attr_sniff_max_interval.attr,
&dev_attr_sniff_min_interval.attr,
NULL
};
static struct attribute_group bt_host_group = {
.attrs = bt_host_attrs,
};
static struct attribute_group *bt_host_groups[] = {
&bt_host_group,
NULL
};
static void bt_host_release(struct device *dev)
{
void *data = dev_get_drvdata(dev);
kfree(data);
}
static struct device_type bt_host = {
.name = "host",
.groups = bt_host_groups,
.release = bt_host_release,
};
int hci_register_sysfs(struct hci_dev *hdev)
{
struct device *dev = &hdev->dev;
int err;
BT_DBG("%p name %s type %d", hdev, hdev->name, hdev->type);
dev->type = &bt_host;
dev->class = bt_class;
dev->parent = hdev->parent;
dev_set_name(dev, "%s", hdev->name);
dev_set_drvdata(dev, hdev);
err = device_register(dev);
if (err < 0)
return err;
return 0;
}
void hci_unregister_sysfs(struct hci_dev *hdev)
{
BT_DBG("%p name %s type %d", hdev, hdev->name, hdev->type);
device_del(&hdev->dev);
}
int __init bt_sysfs_init(void)
{
bt_workq = create_singlethread_workqueue("bluetooth");
if (!bt_workq)
return -ENOMEM;
bt_class = class_create(THIS_MODULE, "bluetooth");
if (IS_ERR(bt_class)) {
destroy_workqueue(bt_workq);
return PTR_ERR(bt_class);
}
return 0;
}
void bt_sysfs_cleanup(void)
{
destroy_workqueue(bt_workq);
class_destroy(bt_class);
}