iwlwifi: validate MPDU length against notification length

The MPDU contained in a notification shouldn't be larger than the
notification size itself is, validate this.
Reported-by: NHaggai Abramovsky <haggai.abramovsky@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.7c721ad37014.Id5746874ecfa208b60baa62691b2d9dc5dd4d89c@changeidSigned-off-by: NLuca Coelho <luciano.coelho@intel.com>

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

@@ -3,7 +3,7 @@
  *
  * Copyright(c) 2003 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2015 Intel Deutschland GmbH
- * Copyright(c) 2018 Intel Corporation
+ * Copyright(c) 2018, 2020 Intel Corporation
  *
  * Portions of this file are derived from the ipw3945 project, as well
  * as portionhelp of the ieee80211 subsystem header files.
@@ -786,7 +786,7 @@ static void iwlagn_rx_reply_rx(struct iwl_priv *priv,
 	struct iwl_rx_phy_res *phy_res;
 	__le32 rx_pkt_status;
 	struct iwl_rx_mpdu_res_start *amsdu;
-	u32 len;
+	u32 len, pkt_len = iwl_rx_packet_len(pkt);
 	u32 ampdu_status;
 	u32 rate_n_flags;
 
@@ -798,6 +798,12 @@ static void iwlagn_rx_reply_rx(struct iwl_priv *priv,
 	amsdu = (struct iwl_rx_mpdu_res_start *)pkt->data;
 	header = (struct ieee80211_hdr *)(pkt->data + sizeof(*amsdu));
 	len = le16_to_cpu(amsdu->byte_count);
+
+	if (unlikely(len + sizeof(*amsdu) + sizeof(__le32) > pkt_len)) {
+		IWL_DEBUG_DROP(priv, "FW lied about packet len\n");
+		return;
+	}
+
 	rx_pkt_status = *(__le32 *)(pkt->data + sizeof(*amsdu) + len);
 	ampdu_status = iwlagn_translate_rx_status(priv,
 						  le32_to_cpu(rx_pkt_status));

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

@@ -349,7 +349,7 @@ void iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct napi_struct *napi,
 	struct iwl_rx_mpdu_res_start *rx_res;
 	struct ieee80211_sta *sta = NULL;
 	struct sk_buff *skb;
-	u32 len;
+	u32 len, pkt_len = iwl_rx_packet_payload_len(pkt);
 	u32 rate_n_flags;
 	u32 rx_pkt_status;
 	u8 crypt_len = 0;
@@ -358,6 +358,12 @@ void iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct napi_struct *napi,
 	rx_res = (struct iwl_rx_mpdu_res_start *)pkt->data;
 	hdr = (struct ieee80211_hdr *)(pkt->data + sizeof(*rx_res));
 	len = le16_to_cpu(rx_res->byte_count);
+
+	if (unlikely(len + sizeof(*rx_res) + sizeof(__le32) > pkt_len)) {
+		IWL_DEBUG_DROP(mvm, "FW lied about packet len\n");
+		return;
+	}
+
 	rx_pkt_status = get_unaligned_le32((__le32 *)
 		(pkt->data + sizeof(*rx_res) + len));
 

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

@@ -1607,6 +1607,7 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 	struct iwl_rx_mpdu_desc *desc = (void *)pkt->data;
 	struct ieee80211_hdr *hdr;
 	u32 len = le16_to_cpu(desc->mpdu_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);
 	struct ieee80211_sta *sta = NULL;
@@ -1653,6 +1654,11 @@ void iwl_mvm_rx_mpdu_mq(struct iwl_mvm *mvm, struct napi_struct *napi,
 			le32_get_bits(phy_data.d1,
 				      IWL_RX_PHY_DATA1_INFO_TYPE_MASK);
 
+	if (len + desc_size > pkt_len) {
+		IWL_DEBUG_DROP(mvm, "FW lied about packet len\n");
+		return;
+	}
+
 	hdr = (void *)(pkt->data + desc_size);
 	/* Dont use dev_alloc_skb(), we'll have enough headroom once
 	 * ieee80211_hdr pulled.