iwlwifi: mvm: check PN for CCMP/GCMP in the driver

As we're working on multi-queue RX, we want to parallelise checking
the PN in order to avoid having to serialise the RX processing.

It may seem that doing parallel PN checking is insecure, but it turns
out to be OK because queue assignment is done based on the data in the
frame (IP/TCP) and thus cannot be manipulated by an attacker, since
the data is encrypted and must first have been decrypted successfully.

There are some corner cases, in particular when the peer starts using
fragmentation which redirects the packet to the default queue. However
this redirection is remembered (for the STA, per TID) and thus cannot
be exploited by an attacker either.

Leave checking on the default queue (queue 0) to mac80211, since we
get fragmented packets there and those are subject to stricter checks
during reassembly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index 40b5c5378bd2..d70a1716f3e0 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -2568,6 +2568,9 @@ static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 			       struct ieee80211_key_conf *key)
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+	struct iwl_mvm_sta *mvmsta;
+	struct iwl_mvm_key_pn *ptk_pn;
+	int keyidx = key->keyidx;
 	int ret;
 	u8 key_offset;
 
@@ -2635,6 +2638,36 @@ static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 			break;
 		}
 
+		if (!test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status) &&
+		    sta && iwl_mvm_has_new_rx_api(mvm) &&
+		    key->flags & IEEE80211_KEY_FLAG_PAIRWISE &&
+		    (key->cipher == WLAN_CIPHER_SUITE_CCMP ||
+		     key->cipher == WLAN_CIPHER_SUITE_GCMP)) {
+			struct ieee80211_key_seq seq;
+			int tid, q;
+
+			mvmsta = iwl_mvm_sta_from_mac80211(sta);
+			WARN_ON(rcu_access_pointer(mvmsta->ptk_pn[keyidx]));
+			ptk_pn = kzalloc(sizeof(*ptk_pn) +
+					 mvm->trans->num_rx_queues *
+						sizeof(ptk_pn->q[0]),
+					 GFP_KERNEL);
+			if (!ptk_pn) {
+				ret = -ENOMEM;
+				break;
+			}
+
+			for (tid = 0; tid < IWL_MAX_TID_COUNT; tid++) {
+				ieee80211_get_key_rx_seq(key, tid, &seq);
+				for (q = 0; q < mvm->trans->num_rx_queues; q++)
+					memcpy(ptk_pn->q[q].pn[tid],
+					       seq.ccmp.pn,
+					       IEEE80211_CCMP_PN_LEN);
+			}
+
+			rcu_assign_pointer(mvmsta->ptk_pn[keyidx], ptk_pn);
+		}
+
 		/* in HW restart reuse the index, otherwise request a new one */
 		if (test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status))
 			key_offset = key->hw_key_idx;
@@ -2660,6 +2693,19 @@ static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 			break;
 		}
 
+		if (sta && iwl_mvm_has_new_rx_api(mvm) &&
+		    key->flags & IEEE80211_KEY_FLAG_PAIRWISE &&
+		    (key->cipher == WLAN_CIPHER_SUITE_CCMP ||
+		     key->cipher == WLAN_CIPHER_SUITE_GCMP)) {
+			mvmsta = iwl_mvm_sta_from_mac80211(sta);
+			ptk_pn = rcu_dereference_protected(
+						mvmsta->ptk_pn[keyidx],
+						lockdep_is_held(&mvm->mutex));
+			RCU_INIT_POINTER(mvmsta->ptk_pn[keyidx], NULL);
+			if (ptk_pn)
+				kfree_rcu(ptk_pn, rcu_head);
+		}
+
 		IWL_DEBUG_MAC80211(mvm, "disable hwcrypto key\n");
 		ret = iwl_mvm_remove_sta_key(mvm, vif, sta, key);
 		break;