From 1c3d185a9a0b136a58e73b02912d593d0303d1da Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 18 Oct 2016 23:12:08 +0300 Subject: [PATCH] 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: f89e07d4cf26 ("mac80211: agg-rx: refuse ADDBA Request with timeout update") Reported-by: Emmanuel Grumbach Signed-off-by: Johannes Berg --- net/mac80211/agg-rx.c | 8 ++------ net/mac80211/debugfs_sta.c | 2 +- net/mac80211/sta_info.h | 4 ++-- 3 files changed, 5 insertions(+), 9 deletions(-) diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c index f6749dced021..3b5fd4188f2a 100644 --- a/net/mac80211/agg-rx.c +++ b/net/mac80211/agg-rx.c @@ -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); diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c index a2fcdb47a0e6..14ec63a02669 100644 --- a/net/mac80211/debugfs_sta.c +++ b/net/mac80211/debugfs_sta.c @@ -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); diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index ed5fcb984a01..dd06ef0b8861 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -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)]; -- 2.20.1