diff options
Diffstat (limited to 'net/mac80211/wpa.c')
| -rw-r--r-- | net/mac80211/wpa.c | 44 |
1 files changed, 20 insertions, 24 deletions
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index c9edfcb7a13b..d65728220763 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -301,22 +301,16 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) } -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 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 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 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 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 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 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 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) } 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; } |