[PATCH v2 3/3] ath11k: Build check size of ath11k_skb_cb

Sven Eckelmann sven at narfation.org
Thu Nov 19 10:42:34 EST 2020


It is rather easy to add more entries to ath11k_skb_cb while forgetting the
size limit of ieee80211_tx_info->driver_data. So just check this during the
build to reduce the change of accidental buffer overflow in the skbuff->cb.

Signed-off-by: Sven Eckelmann <sven at narfation.org>
---
v2:
- new patch

 drivers/net/wireless/ath/ath11k/core.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
index 5a7915f75e1e..b5ca4455b2e0 100644
--- a/drivers/net/wireless/ath/ath11k/core.h
+++ b/drivers/net/wireless/ath/ath11k/core.h
@@ -909,6 +909,8 @@ static inline const char *ath11k_scan_state_str(enum ath11k_scan_state state)
 
 static inline struct ath11k_skb_cb *ATH11K_SKB_CB(struct sk_buff *skb)
 {
+	BUILD_BUG_ON(sizeof(struct ath11k_skb_cb) >
+		     IEEE80211_TX_INFO_DRIVER_DATA_SIZE);
 	return (struct ath11k_skb_cb *)&IEEE80211_SKB_CB(skb)->driver_data;
 }
 
-- 
2.29.2




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