2022-09-02 07:59:27

by Li Zhong

Subject: [PATCH v1] net/mac80211/agg-tx: check the return value of rcu_dereference_protected_tid_tx()

From: lily <[email protected]>

Check the return value of rcu_dereference_protected_tid_tx(), which
could be NULL and result in null pointer dereference if not checked.

Signed-off-by: Li Zhong <[email protected]>
---
net/mac80211/agg-tx.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 07c892aa8c73..ce5f4a39bce2 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -503,6 +503,8 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
int ret;

tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
+ if (!tid_tx)
+ return;

/*
* Start queuing up packets for this aggregation session.
@@ -742,6 +744,8 @@ static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
lockdep_assert_held(&sta->ampdu_mlme.mtx);

tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
+ if (!tid_tx)
+ return;
params.buf_size = tid_tx->buf_size;
params.amsdu = tid_tx->amsdu;

--
2.25.1

2022-09-02 15:20:08

by Johannes Berg

Subject: Re: [PATCH v1] net/mac80211/agg-tx: check the return value of rcu_dereference_protected_tid_tx()

On Fri, 2022-09-02 at 00:57 -0700, Li Zhong wrote:
> From: lily <[email protected]>
>
> Check the return value of rcu_dereference_protected_tid_tx(), which
> could be NULL and result in null pointer dereference if not checked.
>

Except ... it can't happen?

johannes