mac80111: Add BIP-CMAC-256 cipher

This allows mac80211 to configure BIP-CMAC-256 to the driver and also
use software-implementation within mac80211 when the driver does not
support this with hardware accelaration.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index ae654de..549af11 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -955,6 +955,48 @@ ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 	return TX_CONTINUE;
 }
 
+ieee80211_tx_result
+ieee80211_crypto_aes_cmac_256_encrypt(struct ieee80211_tx_data *tx)
+{
+	struct sk_buff *skb;
+	struct ieee80211_tx_info *info;
+	struct ieee80211_key *key = tx->key;
+	struct ieee80211_mmie_16 *mmie;
+	u8 aad[20];
+	u64 pn64;
+
+	if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
+		return TX_DROP;
+
+	skb = skb_peek(&tx->skbs);
+
+	info = IEEE80211_SKB_CB(skb);
+
+	if (info->control.hw_key)
+		return TX_CONTINUE;
+
+	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
+		return TX_DROP;
+
+	mmie = (struct ieee80211_mmie_16 *)skb_put(skb, sizeof(*mmie));
+	mmie->element_id = WLAN_EID_MMIE;
+	mmie->length = sizeof(*mmie) - 2;
+	mmie->key_id = cpu_to_le16(key->conf.keyidx);
+
+	/* PN = PN + 1 */
+	pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
+
+	bip_ipn_set64(mmie->sequence_number, pn64);
+
+	bip_aad(skb, aad);
+
+	/* MIC = AES-256-CMAC(IGTK, AAD || Management Frame Body || MMIE, 128)
+	 */
+	ieee80211_aes_cmac_256(key->u.aes_cmac.tfm, aad,
+			       skb->data + 24, skb->len - 24, mmie->mic);
+
+	return TX_CONTINUE;
+}
 
 ieee80211_rx_result
 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
@@ -1006,6 +1048,56 @@ ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 	return RX_CONTINUE;
 }
 
+ieee80211_rx_result
+ieee80211_crypto_aes_cmac_256_decrypt(struct ieee80211_rx_data *rx)
+{
+	struct sk_buff *skb = rx->skb;
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+	struct ieee80211_key *key = rx->key;
+	struct ieee80211_mmie_16 *mmie;
+	u8 aad[20], mic[16], ipn[6];
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+
+	if (!ieee80211_is_mgmt(hdr->frame_control))
+		return RX_CONTINUE;
+
+	/* management frames are already linear */
+
+	if (skb->len < 24 + sizeof(*mmie))
+		return RX_DROP_UNUSABLE;
+
+	mmie = (struct ieee80211_mmie_16 *)
+		(skb->data + skb->len - sizeof(*mmie));
+	if (mmie->element_id != WLAN_EID_MMIE ||
+	    mmie->length != sizeof(*mmie) - 2)
+		return RX_DROP_UNUSABLE; /* Invalid MMIE */
+
+	bip_ipn_swap(ipn, mmie->sequence_number);
+
+	if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
+		key->u.aes_cmac.replays++;
+		return RX_DROP_UNUSABLE;
+	}
+
+	if (!(status->flag & RX_FLAG_DECRYPTED)) {
+		/* hardware didn't decrypt/verify MIC */
+		bip_aad(skb, aad);
+		ieee80211_aes_cmac_256(key->u.aes_cmac.tfm, aad,
+				       skb->data + 24, skb->len - 24, mic);
+		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+			key->u.aes_cmac.icverrors++;
+			return RX_DROP_UNUSABLE;
+		}
+	}
+
+	memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
+
+	/* Remove MMIE */
+	skb_trim(skb, skb->len - sizeof(*mmie));
+
+	return RX_CONTINUE;
+}
+
 ieee80211_tx_result
 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
 {