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mac80211: stop using pointers as userspace cookies

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Even if the pointers are really only accessible to root and used
pretty much only by wpa_supplicant, this is still not great; even
for debugging it'd be easier to have something that's easier to
read and guaranteed to never get reused.

With the recent change to make mac80211 create an ack_skb for the
mgmt-tx path this becomes possible, only the client probe method
needs to also allocate an ack_skb, and we can store the cookie in
that skb.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2015-06-01 23:14:59 +02:00
parent b2eb0ee6d0
commit 3b79af973c
3 changed files with 91 additions and 56 deletions
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3
include/net/mac80211.h
View File

@ -874,6 +874,9 @@ struct ieee80211_tx_info {
u32 flags;
/* 4 bytes free */
} control;
struct {
u64 cookie;
} ack;
struct {
struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
s32 ack_signal;

117
net/mac80211/cfg.c
View File

@ -2546,6 +2546,19 @@ static bool ieee80211_coalesce_started_roc(struct ieee80211_local *local,
return true;
}
static u64 ieee80211_mgmt_tx_cookie(struct ieee80211_local *local)
{
lockdep_assert_held(&local->mtx);
local->roc_cookie_counter++;
/* wow, you wrapped 64 bits ... more likely a bug */
if (WARN_ON(local->roc_cookie_counter == 0))
local->roc_cookie_counter++;
return local->roc_cookie_counter;
}
static int ieee80211_start_roc_work(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_channel *channel,
@ -2583,7 +2596,6 @@ static int ieee80211_start_roc_work(struct ieee80211_local *local,
roc->req_duration = duration;
roc->frame = txskb;
roc->type = type;
roc->mgmt_tx_cookie = (unsigned long)txskb;
roc->sdata = sdata;
INIT_DELAYED_WORK(&roc->work, ieee80211_sw_roc_work);
INIT_LIST_HEAD(&roc->dependents);
@ -2593,17 +2605,10 @@ static int ieee80211_start_roc_work(struct ieee80211_local *local,
* or the SKB (for mgmt TX)
*/
if (!txskb) {
/* local->mtx protects this */
local->roc_cookie_counter++;
roc->cookie = local->roc_cookie_counter;
/* wow, you wrapped 64 bits ... more likely a bug */
if (WARN_ON(roc->cookie == 0)) {
roc->cookie = 1;
local->roc_cookie_counter++;
}
roc->cookie = ieee80211_mgmt_tx_cookie(local);
*cookie = roc->cookie;
} else {
*cookie = (unsigned long)txskb;
roc->mgmt_tx_cookie = *cookie;
}
/* if there's one pending or we're scanning, queue this one */
@ -3284,6 +3289,36 @@ int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
return err;
}
static struct sk_buff *ieee80211_make_ack_skb(struct ieee80211_local *local,
struct sk_buff *skb, u64 *cookie,
gfp_t gfp)
{
unsigned long spin_flags;
struct sk_buff *ack_skb;
int id;
ack_skb = skb_copy(skb, gfp);
if (!ack_skb)
return ERR_PTR(-ENOMEM);
spin_lock_irqsave(&local->ack_status_lock, spin_flags);
id = idr_alloc(&local->ack_status_frames, ack_skb,
1, 0x10000, GFP_ATOMIC);
spin_unlock_irqrestore(&local->ack_status_lock, spin_flags);
if (id < 0) {
kfree_skb(ack_skb);
return ERR_PTR(-ENOMEM);
}
IEEE80211_SKB_CB(skb)->ack_frame_id = id;
*cookie = ieee80211_mgmt_tx_cookie(local);
IEEE80211_SKB_CB(ack_skb)->ack.cookie = *cookie;
return ack_skb;
}
static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
struct cfg80211_mgmt_tx_params *params,
u64 *cookie)
@ -3429,40 +3464,22 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
skb->dev = sdata->dev;
if (!params->dont_wait_for_ack) {
unsigned long spin_flags;
int id;
/* make a copy to preserve the original cookie (in case the
* driver decides to reallocate the skb) and the frame contents
/* make a copy to preserve the frame contents
* in case of encryption.
*/
ack_skb = skb_copy(skb, GFP_KERNEL);
if (!ack_skb) {
ret = -ENOMEM;
ack_skb = ieee80211_make_ack_skb(local, skb, cookie,
GFP_KERNEL);
if (IS_ERR(ack_skb)) {
ret = PTR_ERR(ack_skb);
kfree_skb(skb);
goto out_unlock;
}
spin_lock_irqsave(&local->ack_status_lock, spin_flags);
id = idr_alloc(&local->ack_status_frames, ack_skb,
1, 0x10000, GFP_ATOMIC);
spin_unlock_irqrestore(&local->ack_status_lock, spin_flags);
if (id < 0) {
ret = -ENOMEM;
kfree_skb(ack_skb);
kfree_skb(skb);
goto out_unlock;
}
IEEE80211_SKB_CB(skb)->ack_frame_id = id;
} else {
/* for cookie below */
ack_skb = skb;
}
if (!need_offchan) {
*cookie = (unsigned long)ack_skb;
ieee80211_tx_skb(sdata, skb);
ret = 0;
goto out_unlock;
@ -3555,7 +3572,7 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;
struct ieee80211_qos_hdr *nullfunc;
struct sk_buff *skb;
struct sk_buff *skb, *ack_skb;
int size = sizeof(*nullfunc);
__le16 fc;
bool qos;
@ -3563,20 +3580,24 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
struct sta_info *sta;
struct ieee80211_chanctx_conf *chanctx_conf;
enum ieee80211_band band;
int ret;
/* the lock is needed to assign the cookie later */
mutex_lock(&local->mtx);
rcu_read_lock();
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (WARN_ON(!chanctx_conf)) {
rcu_read_unlock();
return -EINVAL;
ret = -EINVAL;
goto unlock;
}
band = chanctx_conf->def.chan->band;
sta = sta_info_get_bss(sdata, peer);
if (sta) {
qos = sta->sta.wme;
} else {
rcu_read_unlock();
return -ENOLINK;
ret = -ENOLINK;
goto unlock;
}
if (qos) {
@ -3592,8 +3613,8 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
skb = dev_alloc_skb(local->hw.extra_tx_headroom + size);
if (!skb) {
rcu_read_unlock();
return -ENOMEM;
ret = -ENOMEM;
goto unlock;
}
skb->dev = dev;
@ -3619,13 +3640,23 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
if (qos)
nullfunc->qos_ctrl = cpu_to_le16(7);
ack_skb = ieee80211_make_ack_skb(local, skb, cookie, GFP_ATOMIC);
if (IS_ERR(ack_skb)) {
kfree_skb(skb);
ret = PTR_ERR(ack_skb);
goto unlock;
}
local_bh_disable();
ieee80211_xmit(sdata, sta, skb);
local_bh_enable();
rcu_read_unlock();
*cookie = (unsigned long) skb;
return 0;
ret = 0;
unlock:
rcu_read_unlock();
mutex_unlock(&local->mtx);
return ret;
}
static int ieee80211_cfg_get_channel(struct wiphy *wiphy,

27
net/mac80211/status.c
View File

@ -471,15 +471,23 @@ static void ieee80211_report_ack_skb(struct ieee80211_local *local,
}
if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
u64 cookie = IEEE80211_SKB_CB(skb)->ack.cookie;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_hdr *hdr = (void *)skb->data;
rcu_read_lock();
sdata = ieee80211_sdata_from_skb(local, skb);
if (sdata)
cfg80211_mgmt_tx_status(&sdata->wdev,
(unsigned long)skb,
skb->data, skb->len,
acked, GFP_ATOMIC);
if (sdata) {
if (ieee80211_is_nullfunc(hdr->frame_control) ||
ieee80211_is_qos_nullfunc(hdr->frame_control))
cfg80211_probe_status(sdata->dev, hdr->addr1,
cookie, acked,
GFP_ATOMIC);
else
cfg80211_mgmt_tx_status(&sdata->wdev, cookie,
skb->data, skb->len,
acked, GFP_ATOMIC);
}
rcu_read_unlock();
dev_kfree_skb_any(skb);
@ -499,11 +507,8 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
if (dropped)
acked = false;
if (info->flags & (IEEE80211_TX_INTFL_NL80211_FRAME_TX |
IEEE80211_TX_INTFL_MLME_CONN_TX) &&
!info->ack_frame_id) {
if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
struct ieee80211_sub_if_data *sdata;
u64 cookie = (unsigned long)skb;
rcu_read_lock();
@ -525,10 +530,6 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
ieee80211_mgd_conn_tx_status(sdata,
hdr->frame_control,
acked);
} else if (ieee80211_is_nullfunc(hdr->frame_control) ||
ieee80211_is_qos_nullfunc(hdr->frame_control)) {
cfg80211_probe_status(sdata->dev, hdr->addr1,
cookie, acked, GFP_ATOMIC);
} else {
/* we assign ack frame ID for the others */
WARN_ON(1);