iwlwifi: tighten RX MPDU bounds checks

Previously, we added checks that the contained MPDU size is long
enough, but really we should also check that the notification
itself fits into the data. Add some checks for that.

Also add unlikely() annotations on the previously added checks.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.51cc04cf1e3e.I7bfd6809f8f5feb75f79397646e6656e95688a0e@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/dvm/rx.c

@@ -794,6 +794,12 @@ static void iwlagn_rx_reply_rx(struct iwl_priv *priv,
 		IWL_ERR(priv, "MPDU frame without cached PHY data\n");
 		return;
 	}
+
+	if (unlikely(pkt_len < sizeof(*amsdu))) {
+		IWL_DEBUG_DROP(priv, "Bad REPLY_RX_MPDU_CMD size\n");
+		return;
+	}
+
 	phy_res = &priv->last_phy_res;
 	amsdu = (struct iwl_rx_mpdu_res_start *)pkt->data;
 	header = (struct ieee80211_hdr *)(pkt->data + sizeof(*amsdu));

drivers/net/wireless/intel/iwlwifi/mvm/rx.c

@@ -298,6 +298,11 @@ void iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct napi_struct *napi,
 	u32 rx_pkt_status;
 	u8 crypt_len = 0;
 
+	if (unlikely(pkt_len < sizeof(*rx_res))) {
+		IWL_DEBUG_DROP(mvm, "Bad REPLY_RX_MPDU_CMD size\n");
+		return;
+	}
+
 	phy_info = &mvm->last_phy_info;
 	rx_res = (struct iwl_rx_mpdu_res_start *)pkt->data;
 	hdr = (struct ieee80211_hdr *)(pkt->data + sizeof(*rx_res));

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -1574,16 +1574,15 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
 	struct iwl_rx_mpdu_desc *desc = (void *)pkt->data;
 	struct ieee80211_hdr *hdr;
-	u32 len = le16_to_cpu(desc->mpdu_len);
+	u32 len;
 	u32 pkt_len = iwl_rx_packet_payload_len(pkt);
 	u32 rate_n_flags, gp2_on_air_rise;
-	u16 phy_info = le16_to_cpu(desc->phy_info);
+	u16 phy_info;
 	struct ieee80211_sta *sta = NULL;
 	struct sk_buff *skb;
 	u8 crypt_len = 0, channel, energy_a, energy_b;
 	size_t desc_size;
 	struct iwl_mvm_rx_phy_data phy_data = {
-		.d4 = desc->phy_data4,
 		.info_type = IWL_RX_PHY_INFO_TYPE_NONE,
 	};
 	bool csi = false;
@@ -1591,13 +1590,22 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 	if (unlikely(test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status)))
 		return;
 
+	if (mvm->trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210)
+		desc_size = sizeof(*desc);
+	else
+		desc_size = IWL_RX_DESC_SIZE_V1;
+
+	if (unlikely(pkt_len < desc_size)) {
+		IWL_DEBUG_DROP(mvm, "Bad REPLY_RX_MPDU_CMD size\n");
+		return;
+	}
+
 	if (mvm->trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210) {
 		rate_n_flags = le32_to_cpu(desc->v3.rate_n_flags);
 		channel = desc->v3.channel;
 		gp2_on_air_rise = le32_to_cpu(desc->v3.gp2_on_air_rise);
 		energy_a = desc->v3.energy_a;
 		energy_b = desc->v3.energy_b;
-		desc_size = sizeof(*desc);
 
 		phy_data.d0 = desc->v3.phy_data0;
 		phy_data.d1 = desc->v3.phy_data1;
@@ -1609,7 +1617,6 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 		gp2_on_air_rise = le32_to_cpu(desc->v1.gp2_on_air_rise);
 		energy_a = desc->v1.energy_a;
 		energy_b = desc->v1.energy_b;
-		desc_size = IWL_RX_DESC_SIZE_V1;
 
 		phy_data.d0 = desc->v1.phy_data0;
 		phy_data.d1 = desc->v1.phy_data1;
@@ -1617,16 +1624,21 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 		phy_data.d3 = desc->v1.phy_data3;
 	}
 
-	if (phy_info & IWL_RX_MPDU_PHY_TSF_OVERLOAD)
-		phy_data.info_type =
-			le32_get_bits(phy_data.d1,
-				      IWL_RX_PHY_DATA1_INFO_TYPE_MASK);
+	len = le16_to_cpu(desc->mpdu_len);
 
-	if (len + desc_size > pkt_len) {
+	if (unlikely(len + desc_size > pkt_len)) {
 		IWL_DEBUG_DROP(mvm, "FW lied about packet len\n");
 		return;
 	}
 
+	phy_info = le16_to_cpu(desc->phy_info);
+	phy_data.d4 = desc->phy_data4;
+
+	if (phy_info & IWL_RX_MPDU_PHY_TSF_OVERLOAD)
+		phy_data.info_type =
+			le32_get_bits(phy_data.d1,
+				      IWL_RX_PHY_DATA1_INFO_TYPE_MASK);
+
 	hdr = (void *)(pkt->data + desc_size);
 	/* Dont use dev_alloc_skb(), we'll have enough headroom once
 	 * ieee80211_hdr pulled.