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linux/net/wireless/ibss.c
Johannes Berg 59bbb6f757 cfg80211: validate channel settings across interfaces 
Currently, there's a problem that affects regulatory
enforcement and connection stability, in that it is
possible to switch the channel while connected to a
network or joined to an IBSS.

The problem comes from the fact that we only validate
the channel against the current interface's type, not
against any other interface. Thus, you have any type
of interface up, additionally bring up a monitor mode
interface and switch the channel on the monitor. This
will obviously also switch the channel on the other
interface.

The problem now is that if you do that while sending
beacons for IBSS mode, you can switch to a disabled
channel or a channel that doesn't allow beaconing.
Combined with a managed mode interface connected to
an AP instead of an IBSS interface, you can easily
break the connection that way.

To fix this, this patch validates any channel change
with all available interfaces, and disallows such
changes on secondary interfaces if another interface
is connected to an AP or joined to an IBSS.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-14 09:13:42 -04:00

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/*
* Some IBSS support code for cfg80211.
*
* Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
*/
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <net/cfg80211.h>
#include "wext-compat.h"
#include "nl80211.h"
void __cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_bss *bss;
#ifdef CONFIG_WIRELESS_EXT
union iwreq_data wrqu;
#endif
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return;
if (WARN_ON(!wdev->ssid_len))
return;
bss = cfg80211_get_bss(wdev->wiphy, NULL, bssid,
wdev->ssid, wdev->ssid_len,
WLAN_CAPABILITY_IBSS, WLAN_CAPABILITY_IBSS);
if (WARN_ON(!bss))
return;
if (wdev->current_bss) {
cfg80211_unhold_bss(wdev->current_bss);
cfg80211_put_bss(&wdev->current_bss->pub);
}
cfg80211_hold_bss(bss_from_pub(bss));
wdev->current_bss = bss_from_pub(bss);
cfg80211_upload_connect_keys(wdev);
nl80211_send_ibss_bssid(wiphy_to_dev(wdev->wiphy), dev, bssid,
GFP_KERNEL);
#ifdef CONFIG_WIRELESS_EXT
memset(&wrqu, 0, sizeof(wrqu));
memcpy(wrqu.ap_addr.sa_data, bssid, ETH_ALEN);
wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
#endif
}
void cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid, gfp_t gfp)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
struct cfg80211_event *ev;
unsigned long flags;
ev = kzalloc(sizeof(*ev), gfp);
if (!ev)
return;
ev->type = EVENT_IBSS_JOINED;
memcpy(ev->cr.bssid, bssid, ETH_ALEN);
spin_lock_irqsave(&wdev->event_lock, flags);
list_add_tail(&ev->list, &wdev->event_list);
spin_unlock_irqrestore(&wdev->event_lock, flags);
schedule_work(&rdev->event_work);
}
EXPORT_SYMBOL(cfg80211_ibss_joined);
int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev,
struct cfg80211_ibss_params *params,
struct cfg80211_cached_keys *connkeys)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct ieee80211_channel *chan;
int err;
ASSERT_WDEV_LOCK(wdev);
chan = rdev_fixed_channel(rdev, wdev);
if (chan && chan != params->channel)
return -EBUSY;
if (wdev->ssid_len)
return -EALREADY;
if (WARN_ON(wdev->connect_keys))
kfree(wdev->connect_keys);
wdev->connect_keys = connkeys;
#ifdef CONFIG_WIRELESS_EXT
wdev->wext.ibss.channel = params->channel;
#endif
err = rdev->ops->join_ibss(&rdev->wiphy, dev, params);
if (err) {
wdev->connect_keys = NULL;
return err;
}
memcpy(wdev->ssid, params->ssid, params->ssid_len);
wdev->ssid_len = params->ssid_len;
return 0;
}
int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev,
struct cfg80211_ibss_params *params,
struct cfg80211_cached_keys *connkeys)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = __cfg80211_join_ibss(rdev, dev, params, connkeys);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
static void __cfg80211_clear_ibss(struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
int i;
ASSERT_WDEV_LOCK(wdev);
kfree(wdev->connect_keys);
wdev->connect_keys = NULL;
/*
* Delete all the keys ... pairwise keys can't really
* exist any more anyway, but default keys might.
*/
if (rdev->ops->del_key)
for (i = 0; i < 6; i++)
rdev->ops->del_key(wdev->wiphy, dev, i, NULL);
if (wdev->current_bss) {
cfg80211_unhold_bss(wdev->current_bss);
cfg80211_put_bss(&wdev->current_bss->pub);
}
wdev->current_bss = NULL;
wdev->ssid_len = 0;
#ifdef CONFIG_WIRELESS_EXT
if (!nowext)
wdev->wext.ibss.ssid_len = 0;
#endif
}
void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
wdev_lock(wdev);
__cfg80211_clear_ibss(dev, nowext);
wdev_unlock(wdev);
}
static int __cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
ASSERT_WDEV_LOCK(wdev);
if (!wdev->ssid_len)
return -ENOLINK;
err = rdev->ops->leave_ibss(&rdev->wiphy, dev);
if (err)
return err;
__cfg80211_clear_ibss(dev, nowext);
return 0;
}
int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
struct net_device *dev, bool nowext)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
int err;
wdev_lock(wdev);
err = __cfg80211_leave_ibss(rdev, dev, nowext);
wdev_unlock(wdev);
return err;
}
#ifdef CONFIG_WIRELESS_EXT
int cfg80211_ibss_wext_join(struct cfg80211_registered_device *rdev,
struct wireless_dev *wdev)
{
struct cfg80211_cached_keys *ck = NULL;
enum ieee80211_band band;
int i, err;
ASSERT_WDEV_LOCK(wdev);
if (!wdev->wext.ibss.beacon_interval)
wdev->wext.ibss.beacon_interval = 100;
/* try to find an IBSS channel if none requested ... */
if (!wdev->wext.ibss.channel) {
for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
struct ieee80211_supported_band *sband;
struct ieee80211_channel *chan;
sband = rdev->wiphy.bands[band];
if (!sband)
continue;
for (i = 0; i < sband->n_channels; i++) {
chan = &sband->channels[i];
if (chan->flags & IEEE80211_CHAN_NO_IBSS)
continue;
if (chan->flags & IEEE80211_CHAN_DISABLED)
continue;
wdev->wext.ibss.channel = chan;
break;
}
if (wdev->wext.ibss.channel)
break;
}
if (!wdev->wext.ibss.channel)
return -EINVAL;
}
/* don't join -- SSID is not there */
if (!wdev->wext.ibss.ssid_len)
return 0;
if (!netif_running(wdev->netdev))
return 0;
if (wdev->wext.keys)
wdev->wext.keys->def = wdev->wext.default_key;
wdev->wext.ibss.privacy = wdev->wext.default_key != -1;
if (wdev->wext.keys) {
ck = kmemdup(wdev->wext.keys, sizeof(*ck), GFP_KERNEL);
if (!ck)
return -ENOMEM;
for (i = 0; i < 6; i++)
ck->params[i].key = ck->data[i];
}
err = __cfg80211_join_ibss(rdev, wdev->netdev,
&wdev->wext.ibss, ck);
if (err)
kfree(ck);
return err;
}
int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
struct iw_request_info *info,
struct iw_freq *wextfreq, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
struct ieee80211_channel *chan = NULL;
int err, freq;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
freq = cfg80211_wext_freq(wdev->wiphy, wextfreq);
if (freq < 0)
return freq;
if (freq) {
chan = ieee80211_get_channel(wdev->wiphy, freq);
if (!chan)
return -EINVAL;
if (chan->flags & IEEE80211_CHAN_NO_IBSS ||
chan->flags & IEEE80211_CHAN_DISABLED)
return -EINVAL;
}
if (wdev->wext.ibss.channel == chan)
return 0;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
if (chan) {
wdev->wext.ibss.channel = chan;
wdev->wext.ibss.channel_fixed = true;
} else {
/* cfg80211_ibss_wext_join will pick one if needed */
wdev->wext.ibss.channel_fixed = false;
}
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwfreq(struct net_device *dev,
struct iw_request_info *info,
struct iw_freq *freq, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct ieee80211_channel *chan = NULL;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
wdev_lock(wdev);
if (wdev->current_bss)
chan = wdev->current_bss->pub.channel;
else if (wdev->wext.ibss.channel)
chan = wdev->wext.ibss.channel;
wdev_unlock(wdev);
if (chan) {
freq->m = chan->center_freq;
freq->e = 6;
return 0;
}
/* no channel if not joining */
return -EINVAL;
}
int cfg80211_ibss_wext_siwessid(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
size_t len = data->length;
int err;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
/* iwconfig uses nul termination in SSID.. */
if (len > 0 && ssid[len - 1] == '\0')
len--;
wdev->wext.ibss.ssid = wdev->ssid;
memcpy(wdev->wext.ibss.ssid, ssid, len);
wdev->wext.ibss.ssid_len = len;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwessid(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
data->flags = 0;
wdev_lock(wdev);
if (wdev->ssid_len) {
data->flags = 1;
data->length = wdev->ssid_len;
memcpy(ssid, wdev->ssid, data->length);
} else if (wdev->wext.ibss.ssid && wdev->wext.ibss.ssid_len) {
data->flags = 1;
data->length = wdev->wext.ibss.ssid_len;
memcpy(ssid, wdev->wext.ibss.ssid, data->length);
}
wdev_unlock(wdev);
return 0;
}
int cfg80211_ibss_wext_siwap(struct net_device *dev,
struct iw_request_info *info,
struct sockaddr *ap_addr, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
u8 *bssid = ap_addr->sa_data;
int err;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
if (!rdev->ops->join_ibss)
return -EOPNOTSUPP;
if (ap_addr->sa_family != ARPHRD_ETHER)
return -EINVAL;
/* automatic mode */
if (is_zero_ether_addr(bssid) || is_broadcast_ether_addr(bssid))
bssid = NULL;
/* both automatic */
if (!bssid && !wdev->wext.ibss.bssid)
return 0;
/* fixed already - and no change */
if (wdev->wext.ibss.bssid && bssid &&
compare_ether_addr(bssid, wdev->wext.ibss.bssid) == 0)
return 0;
wdev_lock(wdev);
err = 0;
if (wdev->ssid_len)
err = __cfg80211_leave_ibss(rdev, dev, true);
wdev_unlock(wdev);
if (err)
return err;
if (bssid) {
memcpy(wdev->wext.bssid, bssid, ETH_ALEN);
wdev->wext.ibss.bssid = wdev->wext.bssid;
} else
wdev->wext.ibss.bssid = NULL;
mutex_lock(&rdev->devlist_mtx);
wdev_lock(wdev);
err = cfg80211_ibss_wext_join(rdev, wdev);
wdev_unlock(wdev);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
int cfg80211_ibss_wext_giwap(struct net_device *dev,
struct iw_request_info *info,
struct sockaddr *ap_addr, char *extra)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
/* call only for ibss! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
return -EINVAL;
ap_addr->sa_family = ARPHRD_ETHER;
wdev_lock(wdev);
if (wdev->current_bss)
memcpy(ap_addr->sa_data, wdev->current_bss->pub.bssid, ETH_ALEN);
else if (wdev->wext.ibss.bssid)
memcpy(ap_addr->sa_data, wdev->wext.ibss.bssid, ETH_ALEN);
else
memset(ap_addr->sa_data, 0, ETH_ALEN);
wdev_unlock(wdev);
return 0;
}
#endif
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