Re: [PATCH ath-next 1/2] wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi

[Baochen Qiang <baochen.qiang@oss.qualcomm.com>]

On 5/12/2026 10:23 AM, Miaoqing Pan wrote:
> In certain cases, hardware might provide packets with a
> length greater than the maximum native Wi-Fi header length.
> This can lead to accessing and modifying fields in the header
> within the ath11k_dp_rx_h_undecap_nwifi() function for the
> DP_RX_DECAP_TYPE_NATIVE_WIFI decap type and
> potentially result in invalid data access and memory corruption.
> 
> Kernel stack is corrupted in: ath11k_dp_rx_h_undecap+0x6b0/0x6b0 [ath11k]
> Call trace:
>  ath11k_dp_rx_h_mpdu+0x0/0x2e8 [ath11k]
>  ath11k_dp_rx_h_mpdu+0x1e0/0x2e8 [ath11k]
>  ath11k_dp_rx_wbm_err+0x1e0/0x450 [ath11k]
>  ath11k_dp_rx_process_wbm_err+0x2fc/0x460 [ath11k]
>  ath11k_dp_service_srng+0x2e0/0x348 [ath11k]
> 
> Add a sanity check before processing the SKB to prevent invalid
> data access in the undecap native Wi-Fi function for the
> DP_RX_DECAP_TYPE_NATIVE_WIFI decap type.
> 
> This 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/20250211090302.4105141-1-tamizh.raja@oss.qualcomm.com/ # [1]
> Signed-off-by: Miaoqing Pan <miaoqing.pan@oss.qualcomm.com>
> ---
>  drivers/net/wireless/ath/ath11k/dp_rx.c | 50 +++++++++++++++++++++++--
>  1 file changed, 47 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
> index fe79109adc70..fbe2061a544d 100644
> --- a/drivers/net/wireless/ath/ath11k/dp_rx.c
> +++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
> @@ -2502,6 +2502,29 @@ static void ath11k_dp_rx_deliver_msdu(struct ath11k *ar, struct napi_struct *nap
>  	ieee80211_rx_napi(ar->hw, pubsta, msdu, napi);
>  }
>  
> +static bool ath11k_dp_rx_check_nwifi_hdr_len_valid(struct ath11k_base *ab,
> +						   struct hal_rx_desc *rx_desc,
> +						   struct sk_buff *msdu)
> +{
> +	struct ieee80211_hdr *hdr;
> +	u8 decap_type;
> +	u32 hdr_len;
> +
> +	decap_type = ath11k_dp_rx_h_msdu_start_decap_type(ab, rx_desc);
> +	if (decap_type != DP_RX_DECAP_TYPE_NATIVE_WIFI)
> +		return true;
> +
> +	hdr = (struct ieee80211_hdr *)msdu->data;
> +	hdr_len = ieee80211_hdrlen(hdr->frame_control);
> +
> +	if ((likely(hdr_len <= DP_MAX_NWIFI_HDR_LEN)))

nit: Double parentheses on likely()