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mac80211: fix tid_agg_rx NULL dereference 

On drivers setting the SUPPORTS_REORDERING_BUFFER hardware flag,
we crash when the peer sends an AddBA request while we already
have a session open on the seame TID; this is because on those
drivers, the tid_agg_rx is left NULL even though the session is
valid, and the agg_session_valid bit is set.

To fix this, store the dialog tokens outside the tid_agg_rx to
be able to compare them to the received AddBA request.

Fixes: f89e07d4cf ("mac80211: agg-rx: refuse ADDBA Request with timeout update")
Reported-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2016-10-18 23:12:08 +03:00
parent a1264c3d6c
commit 1c3d185a9a
3 changed files with 5 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
net/mac80211/agg-rx.c
View File

@ -315,11 +315,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
mutex_lock(&sta->ampdu_mlme.mtx);
if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
tid_agg_rx = rcu_dereference_protected(
sta->ampdu_mlme.tid_rx[tid],
lockdep_is_held(&sta->ampdu_mlme.mtx));
if (tid_agg_rx->dialog_token == dialog_token) {
if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
ht_dbg_ratelimited(sta->sdata,
"updated AddBA Req from %pM on tid %u\n",
sta->sta.addr, tid);
@ -396,7 +392,6 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
}
/* update data */
tid_agg_rx->dialog_token = dialog_token;
tid_agg_rx->ssn = start_seq_num;
tid_agg_rx->head_seq_num = start_seq_num;
tid_agg_rx->buf_size = buf_size;
@ -418,6 +413,7 @@ end:
if (status == WLAN_STATUS_SUCCESS) {
__set_bit(tid, sta->ampdu_mlme.agg_session_valid);
__clear_bit(tid, sta->ampdu_mlme.unexpected_agg);
sta->ampdu_mlme.tid_rx_token[tid] = dialog_token;
}
mutex_unlock(&sta->ampdu_mlme.mtx);

2
net/mac80211/debugfs_sta.c
View File

@ -205,7 +205,7 @@ static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf,
p += scnprintf(p, sizeof(buf) + buf - p, "%02d", i);
p += scnprintf(p, sizeof(buf) + buf - p, "\t\t%x", !!tid_rx);
p += scnprintf(p, sizeof(buf) + buf - p, "\t%#.2x",
tid_rx ? tid_rx->dialog_token : 0);
tid_rx ? sta->ampdu_mlme.tid_rx_token[i] : 0);
p += scnprintf(p, sizeof(buf) + buf - p, "\t%#.3x",
tid_rx ? tid_rx->ssn : 0);

4
net/mac80211/sta_info.h
View File

@ -184,7 +184,6 @@ struct tid_ampdu_tx {
* @ssn: Starting Sequence Number expected to be aggregated.
* @buf_size: buffer size for incoming A-MPDUs
* @timeout: reset timer value (in TUs).
* @dialog_token: dialog token for aggregation session
* @rcu_head: RCU head used for freeing this struct
* @reorder_lock: serializes access to reorder buffer, see below.
* @auto_seq: used for offloaded BA sessions to automatically pick head_seq_and
@ -213,7 +212,6 @@ struct tid_ampdu_rx {
u16 ssn;
u16 buf_size;
u16 timeout;
u8 dialog_token;
bool auto_seq;
bool removed;
};
@ -225,6 +223,7 @@ struct tid_ampdu_rx {
* to tid_tx[idx], which are protected by the sta spinlock)
* tid_start_tx is also protected by sta->lock.
* @tid_rx: aggregation info for Rx per TID -- RCU protected
* @tid_rx_token: dialog tokens for valid aggregation sessions
* @tid_rx_timer_expired: bitmap indicating on which TIDs the
* RX timer expired until the work for it runs
* @tid_rx_stop_requested: bitmap indicating which BA sessions per TID the
@ -243,6 +242,7 @@ struct sta_ampdu_mlme {
struct mutex mtx;
/* rx */
struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];
u8 tid_rx_token[IEEE80211_NUM_TIDS];
unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
unsigned long agg_session_valid[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];