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mac80211: support scan features for improved scan privacy

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Support the new random SN and minimal probe request contents
scan flags for the case of software scan - for hardware scan
the drivers need to opt in, but may need to do only that,
depending on their implementation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
This commit is contained in:
Johannes Berg 2018-05-28 15:47:41 +02:00 committed by Johannes Berg
parent 2e076f1990
commit b9771d41ae
9 changed files with 71 additions and 24 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
net/mac80211/cfg.c
View file

@ -3486,7 +3486,7 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
}
local_bh_disable();
ieee80211_xmit(sdata, sta, skb);
ieee80211_xmit(sdata, sta, skb, 0);
local_bh_enable();
ret = 0;

14
net/mac80211/ieee80211_i.h
View file

@ -165,6 +165,7 @@ typedef unsigned __bitwise ieee80211_tx_result;
#define TX_DROP ((__force ieee80211_tx_result) 1u)
#define TX_QUEUED ((__force ieee80211_tx_result) 2u)
#define IEEE80211_TX_NO_SEQNO BIT(0)
#define IEEE80211_TX_UNICAST BIT(1)
#define IEEE80211_TX_PS_BUFFERED BIT(2)
@ -1880,19 +1881,20 @@ void ieee80211_regulatory_limit_wmm_params(struct ieee80211_sub_if_data *sdata,
void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
bool bss_notify, bool enable_qos);
void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta, struct sk_buff *skb);
struct sta_info *sta, struct sk_buff *skb,
u32 txdata_flags);
void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb, int tid,
enum nl80211_band band);
enum nl80211_band band, u32 txdata_flags);
static inline void
ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb, int tid,
enum nl80211_band band)
enum nl80211_band band, u32 txdata_flags)
{
rcu_read_lock();
__ieee80211_tx_skb_tid_band(sdata, skb, tid, band);
__ieee80211_tx_skb_tid_band(sdata, skb, tid, band, txdata_flags);
rcu_read_unlock();
}
@ -1910,7 +1912,7 @@ static inline void ieee80211_tx_skb_tid(struct ieee80211_sub_if_data *sdata,
}
__ieee80211_tx_skb_tid_band(sdata, skb, tid,
chanctx_conf->def.chan->band);
chanctx_conf->def.chan->band, 0);
rcu_read_unlock();
}
@ -2034,6 +2036,8 @@ void ieee80211_send_deauth_disassoc(struct ieee80211_sub_if_data *sdata,
enum {
IEEE80211_PROBE_FLAG_DIRECTED = BIT(0),
IEEE80211_PROBE_FLAG_MIN_CONTENT = BIT(1),
IEEE80211_PROBE_FLAG_RANDOM_SN = BIT(2),
};
int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,

13
net/mac80211/main.c
View file

@ -557,10 +557,19 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
wiphy_ext_feature_set(wiphy,
NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211);
if (!ops->hw_scan)
if (!ops->hw_scan) {
wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN |
NL80211_FEATURE_AP_SCAN;
/*
* if the driver behaves correctly using the probe request
* (template) from mac80211, then both of these should be
* supported even with hw scan - but let drivers opt in.
*/
wiphy_ext_feature_set(wiphy,
NL80211_EXT_FEATURE_SCAN_RANDOM_SN);
wiphy_ext_feature_set(wiphy,
NL80211_EXT_FEATURE_SCAN_MIN_PREQ_CONTENT);
}
if (!ops->set_key)
wiphy->flags |= WIPHY_FLAG_IBSS_RSN;

2
net/mac80211/offchannel.c
View file

@ -262,7 +262,7 @@ static void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc,
if (roc->mgmt_tx_cookie) {
if (!WARN_ON(!roc->frame)) {
ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
roc->chan->band);
roc->chan->band, 0);
roc->frame = NULL;
}
} else {

2
net/mac80211/rx.c
View file

@ -3241,7 +3241,7 @@ ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
}
__ieee80211_tx_skb_tid_band(rx->sdata, nskb, 7,
status->band);
status->band, 0);
}
dev_kfree_skb(rx->skb);
return RX_QUEUED;

35
net/mac80211/scan.c
View file

@ -20,6 +20,7 @@
#include <net/sch_generic.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/random.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
@ -293,6 +294,7 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
struct cfg80211_chan_def chandef;
u8 bands_used = 0;
int i, ielen, n_chans;
u32 flags = 0;
req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
@ -331,12 +333,16 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
local->hw_scan_req->req.n_channels = n_chans;
ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
ielen = ieee80211_build_preq_ies(local,
(u8 *)local->hw_scan_req->req.ie,
local->hw_scan_ies_bufsize,
&local->hw_scan_req->ies,
req->ie, req->ie_len,
bands_used, req->rates, &chandef, 0);
bands_used, req->rates, &chandef,
flags);
local->hw_scan_req->req.ie_len = ielen;
local->hw_scan_req->req.no_cck = req->no_cck;
ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
@ -536,13 +542,24 @@ static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
struct ieee80211_channel *channel)
{
struct sk_buff *skb;
u32 txdata_flags = 0;
skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
ssid, ssid_len,
ie, ie_len, flags);
if (skb) {
if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
struct ieee80211_hdr *hdr = (void *)skb->data;
u16 sn = get_random_u32();
txdata_flags |= IEEE80211_TX_NO_SEQNO;
hdr->seq_ctrl =
cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
}
IEEE80211_SKB_CB(skb)->flags |= tx_flags;
ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
txdata_flags);
}
}
@ -553,7 +570,7 @@ static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata;
struct cfg80211_scan_request *scan_req;
enum nl80211_band band = local->hw.conf.chandef.chan->band;
u32 tx_flags;
u32 flags = 0, tx_flags;
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
@ -561,6 +578,10 @@ static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
if (scan_req->no_cck)
tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
sdata = rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx));
@ -570,7 +591,7 @@ static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
sdata, local->scan_addr, scan_req->bssid,
scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
scan_req->ie, scan_req->ie_len,
scan_req->rates[band], 0,
scan_req->rates[band], flags,
tx_flags, local->hw.conf.chandef.chan);
/*
@ -1159,6 +1180,7 @@ int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
u32 rate_masks[NUM_NL80211_BANDS] = {};
u8 bands_used = 0;
u8 *ie;
u32 flags = 0;
iebufsz = local->scan_ies_len + req->ie_len;
@ -1175,6 +1197,9 @@ int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
}
}
if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
if (!ie) {
ret = -ENOMEM;
@ -1186,7 +1211,7 @@ int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
&sched_scan_ies, req->ie,
req->ie_len, bands_used, rate_masks, &chandef,
0);
flags);
ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
if (ret == 0) {

2
net/mac80211/sta_info.c
View file

@ -1391,7 +1391,7 @@ static void ieee80211_send_null_response(struct sta_info *sta, int tid,
}
info->band = chanctx_conf->def.chan->band;
ieee80211_xmit(sdata, sta, skb);
ieee80211_xmit(sdata, sta, skb, 0);
rcu_read_unlock();
}

21
net/mac80211/tx.c
View file

@ -825,6 +825,8 @@ ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
*/
if (!ieee80211_is_data_qos(hdr->frame_control) ||
is_multicast_ether_addr(hdr->addr1)) {
if (tx->flags & IEEE80211_TX_NO_SEQNO)
return TX_CONTINUE;
/* driver should assign sequence number */
info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
/* for pure STA mode without beacons, we can do it */
@ -1854,7 +1856,7 @@ EXPORT_SYMBOL(ieee80211_tx_prepare_skb);
*/
static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta, struct sk_buff *skb,
bool txpending)
bool txpending, u32 txdata_flags)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_tx_data tx;
@ -1872,6 +1874,8 @@ static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
led_len = skb->len;
res_prepare = ieee80211_tx_prepare(sdata, &tx, sta, skb);
tx.flags |= txdata_flags;
if (unlikely(res_prepare == TX_DROP)) {
ieee80211_free_txskb(&local->hw, skb);
return true;
@ -1933,7 +1937,8 @@ static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
}
void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta, struct sk_buff *skb)
struct sta_info *sta, struct sk_buff *skb,
u32 txdata_flags)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
@ -1968,7 +1973,7 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
}
ieee80211_set_qos_hdr(sdata, skb);
ieee80211_tx(sdata, sta, skb, false);
ieee80211_tx(sdata, sta, skb, false, txdata_flags);
}
static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
@ -2289,7 +2294,7 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
if (!ieee80211_parse_tx_radiotap(local, skb))
goto fail_rcu;
ieee80211_xmit(sdata, NULL, skb);
ieee80211_xmit(sdata, NULL, skb, 0);
rcu_read_unlock();
return NETDEV_TX_OK;
@ -3648,7 +3653,7 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
ieee80211_tx_stats(dev, skb->len);
ieee80211_xmit(sdata, sta, skb);
ieee80211_xmit(sdata, sta, skb, 0);
}
goto out;
out_free:
@ -3867,7 +3872,7 @@ static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
return true;
}
info->band = chanctx_conf->def.chan->band;
result = ieee80211_tx(sdata, NULL, skb, true);
result = ieee80211_tx(sdata, NULL, skb, true, 0);
} else {
struct sk_buff_head skbs;
@ -4783,7 +4788,7 @@ EXPORT_SYMBOL(ieee80211_unreserve_tid);
void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb, int tid,
enum nl80211_band band)
enum nl80211_band band, u32 txdata_flags)
{
int ac = ieee80211_ac_from_tid(tid);
@ -4800,7 +4805,7 @@ void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
*/
local_bh_disable();
IEEE80211_SKB_CB(skb)->band = band;
ieee80211_xmit(sdata, NULL, skb);
ieee80211_xmit(sdata, NULL, skb, txdata_flags);
local_bh_enable();
}

4
net/mac80211/util.c
View file

@ -1433,6 +1433,9 @@ static int ieee80211_build_preq_ies_band(struct ieee80211_local *local,
chandef->chan->center_freq);
}
if (flags & IEEE80211_PROBE_FLAG_MIN_CONTENT)
goto done;
/* insert custom IEs that go before HT */
if (ie && ie_len) {
static const u8 before_ht[] = {
@ -1510,6 +1513,7 @@ static int ieee80211_build_preq_ies_band(struct ieee80211_local *local,
return pos - buffer;
out_err:
WARN_ONCE(1, "not enough space for preq IEs\n");
done:
return pos - buffer;
}