It was possible to break interface combinations in
the following way:
combo 1: iftype = AP, num_ifaces = 2, num_chans = 2,
combo 2: iftype = AP, num_ifaces = 1, num_chans = 1, radar = HT20
With the above interface combinations it was
possible to:
step 1. start AP on DFS channel by matching combo 2
step 2. start AP on non-DFS channel by matching combo 1
This was possible beacuse (step 2) did not consider
if other interfaces require radar detection.
The patch changes how cfg80211 tracks channels -
instead of channel itself now a complete chandef
is stored.
Signed-off-by: Michal Kazior <[email protected]>
---
include/net/cfg80211.h | 8 +++-----
net/wireless/ap.c | 2 +-
net/wireless/chan.c | 23 +++++++++++++++++++----
net/wireless/core.h | 3 ++-
net/wireless/ibss.c | 2 ++
net/wireless/mesh.c | 6 +++---
net/wireless/mlme.c | 2 +-
net/wireless/nl80211.c | 6 +++---
net/wireless/util.c | 2 +-
9 files changed, 35 insertions(+), 19 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 459700e..09aed62 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3146,8 +3146,8 @@ struct cfg80211_cached_keys;
* @identifier: (private) Identifier used in nl80211 to identify this
* wireless device if it has no netdev
* @current_bss: (private) Used by the internal configuration code
- * @channel: (private) Used by the internal configuration code to track
- * the user-set AP, monitor and WDS channel
+ * @chandef: (private) Used by the internal configuration code to track
+ * the user-set channel definition.
* @preset_chandef: (private) Used by the internal configuration code to
* track the channel to be used for AP later
* @bssid: (private) Used by the internal configuration code
@@ -3211,9 +3211,7 @@ struct wireless_dev {
struct cfg80211_internal_bss *current_bss; /* associated / joined */
struct cfg80211_chan_def preset_chandef;
-
- /* for AP and mesh channel tracking */
- struct ieee80211_channel *channel;
+ struct cfg80211_chan_def chandef;
bool ibss_fixed;
bool ibss_dfs_possible;
diff --git a/net/wireless/ap.c b/net/wireless/ap.c
index 4760d65..68602be 100644
--- a/net/wireless/ap.c
+++ b/net/wireless/ap.c
@@ -27,7 +27,7 @@ static int __cfg80211_stop_ap(struct cfg80211_registered_device *rdev,
err = rdev_stop_ap(rdev, dev);
if (!err) {
wdev->beacon_interval = 0;
- wdev->channel = NULL;
+ memset(&wdev->chandef, 0, sizeof(wdev->chandef));
wdev->ssid_len = 0;
rdev_set_qos_map(rdev, dev, NULL);
nl80211_send_ap_stopped(wdev);
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 78559b5..f8ab7df 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -642,7 +642,8 @@ int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
void
cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
- enum cfg80211_chan_mode *chanmode)
+ enum cfg80211_chan_mode *chanmode,
+ u8 *radar_detect)
{
*chan = NULL;
*chanmode = CHAN_MODE_UNDEFINED;
@@ -660,6 +661,11 @@ cfg80211_get_chan_state(struct wireless_dev *wdev,
!wdev->ibss_dfs_possible)
? CHAN_MODE_SHARED
: CHAN_MODE_EXCLUSIVE;
+
+ /* consider worst-case - IBSS can try to return to the
+ * original user-specified channel as creator */
+ if (wdev->ibss_dfs_possible)
+ *radar_detect |= BIT(wdev->chandef.width);
return;
}
break;
@@ -674,17 +680,26 @@ cfg80211_get_chan_state(struct wireless_dev *wdev,
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_P2P_GO:
if (wdev->cac_started) {
- *chan = wdev->channel;
+ *chan = wdev->chandef.chan;
*chanmode = CHAN_MODE_SHARED;
+ *radar_detect |= BIT(wdev->chandef.width);
} else if (wdev->beacon_interval) {
- *chan = wdev->channel;
+ *chan = wdev->chandef.chan;
*chanmode = CHAN_MODE_SHARED;
+
+ if (cfg80211_chandef_dfs_required(wdev->wiphy,
+ &wdev->chandef))
+ *radar_detect |= BIT(wdev->chandef.width);
}
return;
case NL80211_IFTYPE_MESH_POINT:
if (wdev->mesh_id_len) {
- *chan = wdev->channel;
+ *chan = wdev->chandef.chan;
*chanmode = CHAN_MODE_SHARED;
+
+ if (cfg80211_chandef_dfs_required(wdev->wiphy,
+ &wdev->chandef))
+ *radar_detect |= BIT(wdev->chandef.width);
}
return;
case NL80211_IFTYPE_MONITOR:
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 37ec16d..b4eca21 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -441,7 +441,8 @@ static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
void
cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
- enum cfg80211_chan_mode *chanmode);
+ enum cfg80211_chan_mode *chanmode,
+ u8 *radar_detect);
int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
struct cfg80211_chan_def *chandef);
diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index f911c5f..5e4dd03 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -117,6 +117,7 @@ int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
wdev->ibss_fixed = params->channel_fixed;
wdev->ibss_dfs_possible = params->userspace_handles_dfs;
+ wdev->chandef = params->chandef;
#ifdef CONFIG_CFG80211_WEXT
wdev->wext.ibss.chandef = params->chandef;
#endif
@@ -200,6 +201,7 @@ static void __cfg80211_clear_ibss(struct net_device *dev, bool nowext)
wdev->current_bss = NULL;
wdev->ssid_len = 0;
+ memset(&wdev->chandef, 0, sizeof(wdev->chandef));
#ifdef CONFIG_CFG80211_WEXT
if (!nowext)
wdev->wext.ibss.ssid_len = 0;
diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
index 8858624..d42a3fc 100644
--- a/net/wireless/mesh.c
+++ b/net/wireless/mesh.c
@@ -195,7 +195,7 @@ int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
if (!err) {
memcpy(wdev->ssid, setup->mesh_id, setup->mesh_id_len);
wdev->mesh_id_len = setup->mesh_id_len;
- wdev->channel = setup->chandef.chan;
+ wdev->chandef = setup->chandef;
}
return err;
@@ -244,7 +244,7 @@ int cfg80211_set_mesh_channel(struct cfg80211_registered_device *rdev,
err = rdev_libertas_set_mesh_channel(rdev, wdev->netdev,
chandef->chan);
if (!err)
- wdev->channel = chandef->chan;
+ wdev->chandef = *chandef;
return err;
}
@@ -276,7 +276,7 @@ static int __cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
err = rdev_leave_mesh(rdev, dev);
if (!err) {
wdev->mesh_id_len = 0;
- wdev->channel = NULL;
+ memset(&wdev->chandef, 0, sizeof(wdev->chandef));
rdev_set_qos_map(rdev, dev, NULL);
}
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 52cca05..d47c9d1 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -772,7 +772,7 @@ void cfg80211_cac_event(struct net_device *netdev,
if (WARN_ON(!wdev->cac_started))
return;
- if (WARN_ON(!wdev->channel))
+ if (WARN_ON(!wdev->chandef.chan))
return;
switch (event) {
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 6753203..7f6cd3a 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3309,7 +3309,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
if (!err) {
wdev->preset_chandef = params.chandef;
wdev->beacon_interval = params.beacon_interval;
- wdev->channel = params.chandef.chan;
+ wdev->chandef = params.chandef;
wdev->ssid_len = params.ssid_len;
memcpy(wdev->ssid, params.ssid, wdev->ssid_len);
}
@@ -5825,7 +5825,7 @@ static int nl80211_start_radar_detection(struct sk_buff *skb,
err = rdev->ops->start_radar_detection(&rdev->wiphy, dev, &chandef);
if (!err) {
- wdev->channel = chandef.chan;
+ wdev->chandef = chandef;
wdev->cac_started = true;
wdev->cac_start_time = jiffies;
}
@@ -11243,7 +11243,7 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
wdev->iftype != NL80211_IFTYPE_MESH_POINT))
return;
- wdev->channel = chandef->chan;
+ wdev->chandef = *chandef;
nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL);
}
EXPORT_SYMBOL(cfg80211_ch_switch_notify);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index d39c371..847bed7 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1356,7 +1356,7 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
*/
mutex_lock_nested(&wdev_iter->mtx, 1);
__acquire(wdev_iter->mtx);
- cfg80211_get_chan_state(wdev_iter, &ch, &chmode);
+ cfg80211_get_chan_state(wdev_iter, &ch, &chmode, &radar_detect);
wdev_unlock(wdev_iter);
switch (chmode) {
--
1.8.5.3
On 31 January 2014 14:51, Johannes Berg <[email protected]> wrote:
> On Wed, 2014-01-29 at 14:22 +0100, Michal Kazior wrote:
>> It was possible to break interface combinations in
>> the following way:
>>
>> combo 1: iftype = AP, num_ifaces = 2, num_chans = 2,
>> combo 2: iftype = AP, num_ifaces = 1, num_chans = 1, radar = HT20
>>
>> With the above interface combinations it was
>> possible to:
>>
>> step 1. start AP on DFS channel by matching combo 2
>> step 2. start AP on non-DFS channel by matching combo 1
>>
>> This was possible beacuse (step 2) did not consider
>> if other interfaces require radar detection.
>>
>> The patch changes how cfg80211 tracks channels -
>> instead of channel itself now a complete chandef
>> is stored.
>
> Applied.
>
> Do you also want to take this a little further and actually check
> compatibility when checking for channel availability in
> cfg80211_can_use_iftype_chan()? Right now it only checks the channel,
> but cfg80211_get_chan_state() should really not have a channel argument
> but a chandef instead.
I briefly looked at the issue and have seen challenges. Although I'm
not actively implementing it I may end up doing it at some point.
Michał
On Wed, 2014-01-29 at 14:22 +0100, Michal Kazior wrote:
> It was possible to break interface combinations in
> the following way:
>
> combo 1: iftype = AP, num_ifaces = 2, num_chans = 2,
> combo 2: iftype = AP, num_ifaces = 1, num_chans = 1, radar = HT20
>
> With the above interface combinations it was
> possible to:
>
> step 1. start AP on DFS channel by matching combo 2
> step 2. start AP on non-DFS channel by matching combo 1
>
> This was possible beacuse (step 2) did not consider
> if other interfaces require radar detection.
>
> The patch changes how cfg80211 tracks channels -
> instead of channel itself now a complete chandef
> is stored.
Applied.
Do you also want to take this a little further and actually check
compatibility when checking for channel availability in
cfg80211_can_use_iftype_chan()? Right now it only checks the channel,
but cfg80211_get_chan_state() should really not have a channel argument
but a chandef instead.
johannes