[PATCH ath-next 2/2] wifi: ath11k: add MSDU length validation for TKIP MIC error

[Miaoqing Pan]

In the WBM error path, while processing TKIP MIC errors, MSDU length
is fetched from the hal_rx_desc's msdu_end. This MSDU length is
directly passed to skb_put() without validation. In stress test
scenarios, the WBM error ring may receive invalid descriptors, which
could lead to an invalid MSDU length.

To fix this, add a check to drop the skb when the calculated MSDU
length is greater than the skb size.

This is adapted from the discussion/patch of the ath12k driver [1].

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04685-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1

Link: https://lore.kernel.org/linux-wireless/20250416021903.3178962-1-nithyanantham.paramasivam@xxxxxxxxxxxxxxxx/ # [1]
Signed-off-by: Miaoqing Pan <miaoqing.pan@xxxxxxxxxxxxxxxx>
---
 drivers/net/wireless/ath/ath11k/dp_rx.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
index fbe2061a544d..9c31bb7efcc8 100644
--- a/drivers/net/wireless/ath/ath11k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
@@ -4050,6 +4050,15 @@ static bool ath11k_dp_rx_h_tkip_mic_err(struct ath11k *ar, struct sk_buff *msdu,
 
 	l3pad_bytes = ath11k_dp_rx_h_msdu_end_l3pad(ar->ab, desc);
 	msdu_len = ath11k_dp_rx_h_msdu_start_msdu_len(ar->ab, desc);
+
+	if (unlikely(hal_rx_desc_sz + l3pad_bytes + msdu_len > DP_RX_BUFFER_SIZE)) {
+		ath11k_dbg(ab, ATH11K_DBG_DATA,
+			   "invalid msdu len in tkip mic err %u\n", msdu_len);
+		ath11k_dbg_dump(ab, ATH11K_DBG_DATA, NULL, "", desc,
+				sizeof(*desc));
+		return true;
+	}
+
 	skb_put(msdu, hal_rx_desc_sz + l3pad_bytes + msdu_len);
 	skb_pull(msdu, hal_rx_desc_sz + l3pad_bytes);
 
-- 
2.34.1