mac80211: port CCMP to cryptoapi's CCM driver
Use the generic CCM aead chaining mode driver rather than a local
implementation that sits right on top of the core AES cipher.
This allows the use of accelerated implementations of either
CCM as a whole or the CTR mode which it encapsulates.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index c9edfcb..d657282 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -301,22 +301,16 @@
}
-static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
+static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
int encrypted)
{
__le16 mask_fc;
int a4_included, mgmt;
u8 qos_tid;
- u8 *b_0, *aad;
- u16 data_len, len_a;
+ u16 len_a;
unsigned int hdrlen;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
- memset(scratch, 0, 6 * AES_BLOCK_SIZE);
-
- b_0 = scratch + 3 * AES_BLOCK_SIZE;
- aad = scratch + 4 * AES_BLOCK_SIZE;
-
/*
* Mask FC: zero subtype b4 b5 b6 (if not mgmt)
* Retry, PwrMgt, MoreData; set Protected
@@ -338,20 +332,21 @@
else
qos_tid = 0;
- data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN;
- if (encrypted)
- data_len -= IEEE80211_CCMP_MIC_LEN;
+ /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
+ * mode authentication are not allowed to collide, yet both are derived
+ * from this vector b_0. We only set L := 1 here to indicate that the
+ * data size can be represented in (L+1) bytes. The CCM layer will take
+ * care of storing the data length in the top (L+1) bytes and setting
+ * and clearing the other bits as is required to derive the two IVs.
+ */
+ b_0[0] = 0x1;
- /* First block, b_0 */
- b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
/* Nonce: Nonce Flags | A2 | PN
* Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
*/
b_0[1] = qos_tid | (mgmt << 4);
memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
- /* l(m) */
- put_unaligned_be16(data_len, &b_0[14]);
/* AAD (extra authenticate-only data) / masked 802.11 header
* FC | A1 | A2 | A3 | SC | [A4] | [QC] */
@@ -407,7 +402,8 @@
u8 *pos;
u8 pn[6];
u64 pn64;
- u8 scratch[6 * AES_BLOCK_SIZE];
+ u8 aad[2 * AES_BLOCK_SIZE];
+ u8 b_0[AES_BLOCK_SIZE];
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
@@ -460,9 +456,9 @@
return 0;
pos += IEEE80211_CCMP_HDR_LEN;
- ccmp_special_blocks(skb, pn, scratch, 0);
- ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
- pos, skb_put(skb, IEEE80211_CCMP_MIC_LEN));
+ ccmp_special_blocks(skb, pn, b_0, aad, 0);
+ ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
+ skb_put(skb, IEEE80211_CCMP_MIC_LEN));
return 0;
}
@@ -525,16 +521,16 @@
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
- u8 scratch[6 * AES_BLOCK_SIZE];
+ u8 aad[2 * AES_BLOCK_SIZE];
+ u8 b_0[AES_BLOCK_SIZE];
/* hardware didn't decrypt/verify MIC */
- ccmp_special_blocks(skb, pn, scratch, 1);
+ ccmp_special_blocks(skb, pn, b_0, aad, 1);
if (ieee80211_aes_ccm_decrypt(
- key->u.ccmp.tfm, scratch,
+ key->u.ccmp.tfm, b_0, aad,
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
data_len,
- skb->data + skb->len - IEEE80211_CCMP_MIC_LEN,
- skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN))
+ skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
return RX_DROP_UNUSABLE;
}