mac80211: support device/driver PN check for CCMP/GCMP

When there are multiple RX queues, the PN checks in mac80211 cannot be
used since packets might be processed out of order on different CPUs.

Allow the driver to report that the PN has been checked, drivers that
will use multi-queue RX will have to set this flag.

For now, the flag is only valid when the frame has been decrypted, in
theory that restriction doesn't have to be there, but in practice the
hardware will have decrypted the frame already.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 45 insertions, 38 deletions

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 943f760..feb547d 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -516,31 +516,34 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
 			return RX_DROP_UNUSABLE;
 	}
 
-	ccmp_hdr2pn(pn, skb->data + hdrlen);
+	if (!(status->flag & RX_FLAG_PN_VALIDATED)) {
+		ccmp_hdr2pn(pn, skb->data + hdrlen);
 
-	queue = rx->security_idx;
+		queue = rx->security_idx;
 
-	if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
-		key->u.ccmp.replays++;
-		return RX_DROP_UNUSABLE;
-	}
+		if (memcmp(pn, key->u.ccmp.rx_pn[queue],
+			   IEEE80211_CCMP_PN_LEN) <= 0) {
+			key->u.ccmp.replays++;
+			return RX_DROP_UNUSABLE;
+		}
 
-	if (!(status->flag & RX_FLAG_DECRYPTED)) {
-		u8 aad[2 * AES_BLOCK_SIZE];
-		u8 b_0[AES_BLOCK_SIZE];
-		/* hardware didn't decrypt/verify MIC */
-		ccmp_special_blocks(skb, pn, b_0, aad);
+		if (!(status->flag & RX_FLAG_DECRYPTED)) {
+			u8 aad[2 * AES_BLOCK_SIZE];
+			u8 b_0[AES_BLOCK_SIZE];
+			/* hardware didn't decrypt/verify MIC */
+			ccmp_special_blocks(skb, pn, b_0, aad);
+
+			if (ieee80211_aes_ccm_decrypt(
+				    key->u.ccmp.tfm, b_0, aad,
+				    skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
+				    data_len,
+				    skb->data + skb->len - mic_len, mic_len))
+				return RX_DROP_UNUSABLE;
+		}
 
-		if (ieee80211_aes_ccm_decrypt(
-			    key->u.ccmp.tfm, b_0, aad,
-			    skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
-			    data_len,
-			    skb->data + skb->len - mic_len, mic_len))
-			return RX_DROP_UNUSABLE;
+		memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
 	}
 
-	memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
-
 	/* Remove CCMP header and MIC */
 	if (pskb_trim(skb, skb->len - mic_len))
 		return RX_DROP_UNUSABLE;
@@ -739,31 +742,35 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
 			return RX_DROP_UNUSABLE;
 	}
 
-	gcmp_hdr2pn(pn, skb->data + hdrlen);
+	if (!(status->flag & RX_FLAG_PN_VALIDATED)) {
+		gcmp_hdr2pn(pn, skb->data + hdrlen);
 
-	queue = rx->security_idx;
+		queue = rx->security_idx;
 
-	if (memcmp(pn, key->u.gcmp.rx_pn[queue], IEEE80211_GCMP_PN_LEN) <= 0) {
-		key->u.gcmp.replays++;
-		return RX_DROP_UNUSABLE;
-	}
+		if (memcmp(pn, key->u.gcmp.rx_pn[queue],
+			   IEEE80211_GCMP_PN_LEN) <= 0) {
+			key->u.gcmp.replays++;
+			return RX_DROP_UNUSABLE;
+		}
 
-	if (!(status->flag & RX_FLAG_DECRYPTED)) {
-		u8 aad[2 * AES_BLOCK_SIZE];
-		u8 j_0[AES_BLOCK_SIZE];
-		/* hardware didn't decrypt/verify MIC */
-		gcmp_special_blocks(skb, pn, j_0, aad);
+		if (!(status->flag & RX_FLAG_DECRYPTED)) {
+			u8 aad[2 * AES_BLOCK_SIZE];
+			u8 j_0[AES_BLOCK_SIZE];
+			/* hardware didn't decrypt/verify MIC */
+			gcmp_special_blocks(skb, pn, j_0, aad);
+
+			if (ieee80211_aes_gcm_decrypt(
+				    key->u.gcmp.tfm, j_0, aad,
+				    skb->data + hdrlen + IEEE80211_GCMP_HDR_LEN,
+				    data_len,
+				    skb->data + skb->len -
+				    IEEE80211_GCMP_MIC_LEN))
+				return RX_DROP_UNUSABLE;
+		}
 
-		if (ieee80211_aes_gcm_decrypt(
-			    key->u.gcmp.tfm, j_0, aad,
-			    skb->data + hdrlen + IEEE80211_GCMP_HDR_LEN,
-			    data_len,
-			    skb->data + skb->len - IEEE80211_GCMP_MIC_LEN))
-			return RX_DROP_UNUSABLE;
+		memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
 	}
 
-	memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
-
 	/* Remove GCMP header and MIC */
 	if (pskb_trim(skb, skb->len - IEEE80211_GCMP_MIC_LEN))
 		return RX_DROP_UNUSABLE;