wifi: ath12k: fix possible out-of-bound read in ath12k_htt_pull_ppdu_stats()

len is extracted from HTT message and could be an unexpected value in
case errors happen, so add validation before using to avoid possible
out-of-bound read in the following message iteration and parsing.

The same issue also applies to ppdu_info->ppdu_stats.common.num_users,
so validate it before using too.

These are found during code review.

Compile test only.
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230901015602.45112-1-quic_bqiang@quicinc.com

drivers/net/wireless/ath/ath12k/dp_rx.c

@@ -1555,6 +1555,13 @@ static int ath12k_htt_pull_ppdu_stats(struct ath12k_base *ab,
 
 	msg = (struct ath12k_htt_ppdu_stats_msg *)skb->data;
 	len = le32_get_bits(msg->info, HTT_T2H_PPDU_STATS_INFO_PAYLOAD_SIZE);
+	if (len > (skb->len - struct_size(msg, data, 0))) {
+		ath12k_warn(ab,
+			    "HTT PPDU STATS event has unexpected payload size %u, should be smaller than %u\n",
+			    len, skb->len);
+		return -EINVAL;
+	}
+
 	pdev_id = le32_get_bits(msg->info, HTT_T2H_PPDU_STATS_INFO_PDEV_ID);
 	ppdu_id = le32_to_cpu(msg->ppdu_id);
 
@@ -1583,6 +1590,16 @@ static int ath12k_htt_pull_ppdu_stats(struct ath12k_base *ab,
 		goto exit;
 	}
 
+	if (ppdu_info->ppdu_stats.common.num_users >= HTT_PPDU_STATS_MAX_USERS) {
+		spin_unlock_bh(&ar->data_lock);
+		ath12k_warn(ab,
+			    "HTT PPDU STATS event has unexpected num_users %u, should be smaller than %u\n",
+			    ppdu_info->ppdu_stats.common.num_users,
+			    HTT_PPDU_STATS_MAX_USERS);
+		ret = -EINVAL;
+		goto exit;
+	}
+
 	/* back up data rate tlv for all peers */
 	if (ppdu_info->frame_type == HTT_STATS_PPDU_FTYPE_DATA &&
 	    (ppdu_info->tlv_bitmap & (1 << HTT_PPDU_STATS_TAG_USR_COMMON)) &&