From: Jiri Kosina <[email protected]>
ieee80211_tx_h_select_key() is performing a series of RCU dereferences,
but none of the callers seems to be taking RCU read-side lock; let's
acquire the lock in ieee80211_tx_h_select_key() itself.
Spotted with rtw89 driver.
This fixes the splat below.
=============================
WARNING: suspicious RCU usage
5.17.0-rc4-00003-gccad664b7f14 #3 Tainted: G E
-----------------------------
net/mac80211/tx.c:593 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u33:0/184:
#0: ffff9c0b14811d38 ((wq_completion)rtw89_tx_wq){+.+.}-{0:0}, at: process_one_work+0x258/0x660
#1: ffffb97380cf3e78 ((work_completion)(&rtwdev->txq_work)){+.+.}-{0:0}, at: process_one_work+0x258/0x660
stack backtrace:
CPU: 8 PID: 184 Comm: kworker/u33:0 Tainted: G E 5.17.0-rc4-00003-gccad664b7f14 #3 473b49ab0e7c2d6af2900c756bfd04efd7a9de13
Hardware name: LENOVO 20UJS2B905/20UJS2B905, BIOS R1CET63W(1.32 ) 04/09/2021
Workqueue: rtw89_tx_wq rtw89_core_txq_work [rtw89_core]
Call Trace:
<TASK>
dump_stack_lvl+0x58/0x71
ieee80211_tx_h_select_key+0x2c0/0x530 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
process_one_work+0x2d8/0x660
worker_thread+0x39/0x3e0
? process_one_work+0x660/0x660
kthread+0xe5/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>
=============================
WARNING: suspicious RCU usage
5.17.0-rc4-00003-gccad664b7f14 #3 Tainted: G E
-----------------------------
net/mac80211/tx.c:607 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u33:0/184:
#0: ffff9c0b14811d38 ((wq_completion)rtw89_tx_wq){+.+.}-{0:0}, at: process_one_work+0x258/0x660
#1: ffffb97380cf3e78 ((work_completion)(&rtwdev->txq_work)){+.+.}-{0:0}, at: process_one_work+0x258/0x660
stack backtrace:
CPU: 8 PID: 184 Comm: kworker/u33:0 Tainted: G E 5.17.0-rc4-00003-gccad664b7f14 #3 473b49ab0e7c2d6af2900c756bfd04efd7a9de13
Hardware name: LENOVO 20UJS2B905/20UJS2B905, BIOS R1CET63W(1.32 ) 04/09/2021
Workqueue: rtw89_tx_wq rtw89_core_txq_work [rtw89_core]
Call Trace:
<TASK>
dump_stack_lvl+0x58/0x71
ieee80211_tx_h_select_key+0x464/0x530 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
process_one_work+0x2d8/0x660
worker_thread+0x39/0x3e0
? process_one_work+0x660/0x660
kthread+0xe5/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>
Fixes: a0761a301746e ("mac80211: drop data frames without key on encrypted links")
Fixes: 46f6b06050b73 ("mac80211: Encrypt "Group addressed privacy" action frames")
Fixes: 3cfcf6ac6d69d ("mac80211: 802.11w - Use BIP (AES-128-CMAC)")
Fixes: f7e0104c1a4e7 ("mac80211: support separate default keys")
Signed-off-by: Jiri Kosina <[email protected]>
---
Unless I am missing something, this seems to have been buggy for over a
decade ... ?
net/mac80211/tx.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 6d054fed062f..50b33ef70627 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -580,6 +580,7 @@ ieee80211_tx_h_check_control_port_protocol(struct ieee80211_tx_data *tx)
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
{
+ int ret;
struct ieee80211_key *key;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
@@ -589,6 +590,8 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
return TX_CONTINUE;
}
+ rcu_read_lock();
+
if (tx->sta &&
(key = rcu_dereference(tx->sta->ptk[tx->sta->ptk_idx])))
tx->key = key;
@@ -645,18 +648,23 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
}
if (unlikely(tx->key && tx->key->flags & KEY_FLAG_TAINTED &&
- !ieee80211_is_deauth(hdr->frame_control)))
- return TX_DROP;
+ !ieee80211_is_deauth(hdr->frame_control))) {
+ ret = TX_DROP;
+ goto out;
+ }
if (!skip_hw && tx->key &&
tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
info->control.hw_key = &tx->key->conf;
} else if (ieee80211_is_data_present(hdr->frame_control) && tx->sta &&
test_sta_flag(tx->sta, WLAN_STA_USES_ENCRYPTION)) {
- return TX_DROP;
+ ret = TX_DROP;
+ goto out;
}
-
- return TX_CONTINUE;
+ ret = TX_CONTINUE;
+out:
+ rcu_read_unlock();
+ return ret;
}
static ieee80211_tx_result debug_noinline
--
Jiri Kosina
SUSE Labs
>
> ieee80211_tx_h_select_key() is performing a series of RCU dereferences,
> but none of the callers seems to be taking RCU read-side lock; let's
> acquire the lock in ieee80211_tx_h_select_key() itself.
>
but but ...
> ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
> rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
/**
* ieee80211_tx_dequeue - dequeue a packet from a software tx queue
*
* @hw: pointer as obtained from ieee80211_alloc_hw()
* @txq: pointer obtained from station or virtual interface, or from
* ieee80211_next_txq()
*
* Returns the skb if successful, %NULL if no frame was available.
*
* Note that this must be called in an rcu_read_lock() critical section,
* which can only be released after the SKB was handled. Some pointers in
[...]
-> driver bug?
johannes