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* Host AP crypt: host-based CCMP encryption implementation for Host AP driver
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* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation. See README and COPYING for
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//#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/random.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/if_ether.h>
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#include <linux/if_arp.h>
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#include <asm/string.h>
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#include <linux/wireless.h>
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#include "ieee80211.h"
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#include <linux/crypto.h>
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#include <linux/scatterlist.h>
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MODULE_AUTHOR("Jouni Malinen");
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MODULE_DESCRIPTION("Host AP crypt: CCMP");
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MODULE_LICENSE("GPL");
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#define AES_BLOCK_LEN 16
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#define CCMP_HDR_LEN 8
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#define CCMP_MIC_LEN 8
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#define CCMP_TK_LEN 16
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struct ieee80211_ccmp_data {
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u8 tx_pn[CCMP_PN_LEN];
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u8 rx_pn[CCMP_PN_LEN];
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u32 dot11RSNAStatsCCMPFormatErrors;
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u32 dot11RSNAStatsCCMPReplays;
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u32 dot11RSNAStatsCCMPDecryptErrors;
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struct crypto_tfm *tfm;
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/* scratch buffers for virt_to_page() (crypto API) */
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u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
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tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
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u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
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void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
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const u8 pt[16], u8 ct[16])
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crypto_cipher_encrypt_one((void*)tfm, ct, pt);
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static void * ieee80211_ccmp_init(int key_idx)
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struct ieee80211_ccmp_data *priv;
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priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
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priv->key_idx = key_idx;
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priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(priv->tfm)) {
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printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
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crypto_free_cipher((void*)priv->tfm);
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static void ieee80211_ccmp_deinit(void *priv)
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struct ieee80211_ccmp_data *_priv = priv;
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if (_priv && _priv->tfm)
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crypto_free_cipher((void*)_priv->tfm);
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static inline void xor_block(u8 *b, u8 *a, size_t len)
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for (i = 0; i < len; i++)
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static void ccmp_init_blocks(struct crypto_tfm *tfm,
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struct ieee80211_hdr_4addr *hdr,
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u8 *pn, size_t dlen, u8 *b0, u8 *auth,
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int a4_included, qc_included;
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u8 aad[2 * AES_BLOCK_LEN];
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fc = le16_to_cpu(hdr->frame_ctl);
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a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
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(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
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qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
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(WLAN_FC_GET_STYPE(fc) & 0x08));
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// fixed by David :2006.9.6
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qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
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(WLAN_FC_GET_STYPE(fc) & 0x80));
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pos = (u8 *) &hdr->addr4;
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/* CCM Initial Block:
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* Flag (Include authentication header, M=3 (8-octet MIC),
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* L=1 (2-octet Dlen))
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* Nonce: 0x00 | A2 | PN
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memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
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memcpy(b0 + 8, pn, CCMP_PN_LEN);
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b0[14] = (dlen >> 8) & 0xff;
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b0[15] = dlen & 0xff;
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* FC with bits 4..6 and 11..13 masked to zero; 14 is always one
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* SC with bits 4..15 (seq#) masked to zero
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aad[0] = 0; /* aad_len >> 8 */
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aad[1] = aad_len & 0xff;
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aad[2] = pos[0] & 0x8f;
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aad[3] = pos[1] & 0xc7;
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memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
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pos = (u8 *) &hdr->seq_ctl;
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aad[22] = pos[0] & 0x0f;
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aad[23] = 0; /* all bits masked */
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memset(aad + 24, 0, 8);
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memcpy(aad + 24, hdr->addr4, ETH_ALEN);
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aad[a4_included ? 30 : 24] = qc;
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/* rest of QC masked */
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/* Start with the first block and AAD */
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ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
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xor_block(auth, aad, AES_BLOCK_LEN);
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ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
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xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
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ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
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ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
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static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
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struct ieee80211_ccmp_data *key = priv;
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struct ieee80211_hdr_4addr *hdr;
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cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
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if (skb_headroom(skb) < CCMP_HDR_LEN ||
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skb_tailroom(skb) < CCMP_MIC_LEN ||
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data_len = skb->len - hdr_len;
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pos = skb_push(skb, CCMP_HDR_LEN);
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memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
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// mic = skb_put(skb, CCMP_MIC_LEN);
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if (key->tx_pn[i] != 0)
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*pos++ = key->tx_pn[5];
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*pos++ = key->tx_pn[4];
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*pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
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*pos++ = key->tx_pn[3];
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*pos++ = key->tx_pn[2];
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*pos++ = key->tx_pn[1];
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*pos++ = key->tx_pn[0];
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hdr = (struct ieee80211_hdr_4addr *) skb->data;
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if (!tcb_desc->bHwSec)
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int blocks, last, len;
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//mic is moved to here by john
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mic = skb_put(skb, CCMP_MIC_LEN);
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ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
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blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
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last = data_len % AES_BLOCK_LEN;
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for (i = 1; i <= blocks; i++) {
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len = (i == blocks && last) ? last : AES_BLOCK_LEN;
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xor_block(b, pos, len);
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ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
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/* Encryption, with counter */
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b0[14] = (i >> 8) & 0xff;
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ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
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xor_block(pos, e, len);
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for (i = 0; i < CCMP_MIC_LEN; i++)
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mic[i] = b[i] ^ s0[i];
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static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
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struct ieee80211_ccmp_data *key = priv;
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struct ieee80211_hdr_4addr *hdr;
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cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
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if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
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key->dot11RSNAStatsCCMPFormatErrors++;
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hdr = (struct ieee80211_hdr_4addr *) skb->data;
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pos = skb->data + hdr_len;
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if (!(keyidx & (1 << 5))) {
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if (net_ratelimit()) {
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printk(KERN_DEBUG "CCMP: received packet without ExtIV"
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" flag from %pM\n", hdr->addr2);
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key->dot11RSNAStatsCCMPFormatErrors++;
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if (key->key_idx != keyidx) {
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printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
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"keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
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if (net_ratelimit()) {
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printk(KERN_DEBUG "CCMP: received packet from %pM"
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" with keyid=%d that does not have a configured"
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" key\n", hdr->addr2, keyidx);
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if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
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if (net_ratelimit()) {
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printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
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" previous PN %pm received PN %pm\n",
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hdr->addr2, key->rx_pn, pn);
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key->dot11RSNAStatsCCMPReplays++;
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if (!tcb_desc->bHwSec)
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size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
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u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
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int i, blocks, last, len;
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ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
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xor_block(mic, b, CCMP_MIC_LEN);
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blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
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last = data_len % AES_BLOCK_LEN;
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for (i = 1; i <= blocks; i++) {
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len = (i == blocks && last) ? last : AES_BLOCK_LEN;
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/* Decrypt, with counter */
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b0[14] = (i >> 8) & 0xff;
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ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
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xor_block(pos, b, len);
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xor_block(a, pos, len);
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ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
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if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
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if (net_ratelimit()) {
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printk(KERN_DEBUG "CCMP: decrypt failed: STA="
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"%pM\n", hdr->addr2);
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key->dot11RSNAStatsCCMPDecryptErrors++;
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memcpy(key->rx_pn, pn, CCMP_PN_LEN);
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/* Remove hdr and MIC */
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memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
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skb_pull(skb, CCMP_HDR_LEN);
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skb_trim(skb, skb->len - CCMP_MIC_LEN);
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static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
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struct ieee80211_ccmp_data *data = priv;
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struct crypto_tfm *tfm = data->tfm;
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keyidx = data->key_idx;
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memset(data, 0, sizeof(*data));
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data->key_idx = keyidx;
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if (len == CCMP_TK_LEN) {
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memcpy(data->key, key, CCMP_TK_LEN);
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data->rx_pn[0] = seq[5];
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data->rx_pn[1] = seq[4];
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data->rx_pn[2] = seq[3];
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data->rx_pn[3] = seq[2];
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data->rx_pn[4] = seq[1];
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data->rx_pn[5] = seq[0];
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crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
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static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
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struct ieee80211_ccmp_data *data = priv;
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if (len < CCMP_TK_LEN)
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memcpy(key, data->key, CCMP_TK_LEN);
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seq[0] = data->tx_pn[5];
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seq[1] = data->tx_pn[4];
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seq[2] = data->tx_pn[3];
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seq[3] = data->tx_pn[2];
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seq[4] = data->tx_pn[1];
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seq[5] = data->tx_pn[0];
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static char * ieee80211_ccmp_print_stats(char *p, void *priv)
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struct ieee80211_ccmp_data *ccmp = priv;
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p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
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"tx_pn=%pm rx_pn=%pm "
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"format_errors=%d replays=%d decrypt_errors=%d\n",
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ccmp->key_idx, ccmp->key_set,
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ccmp->tx_pn, ccmp->rx_pn,
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ccmp->dot11RSNAStatsCCMPFormatErrors,
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ccmp->dot11RSNAStatsCCMPReplays,
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ccmp->dot11RSNAStatsCCMPDecryptErrors);
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void ieee80211_ccmp_null(void)
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// printk("============>%s()\n", __FUNCTION__);
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static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
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.init = ieee80211_ccmp_init,
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.deinit = ieee80211_ccmp_deinit,
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.encrypt_mpdu = ieee80211_ccmp_encrypt,
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.decrypt_mpdu = ieee80211_ccmp_decrypt,
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.encrypt_msdu = NULL,
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.decrypt_msdu = NULL,
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.set_key = ieee80211_ccmp_set_key,
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.get_key = ieee80211_ccmp_get_key,
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.print_stats = ieee80211_ccmp_print_stats,
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.extra_prefix_len = CCMP_HDR_LEN,
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.extra_postfix_len = CCMP_MIC_LEN,
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.owner = THIS_MODULE,
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int __init ieee80211_crypto_ccmp_init(void)
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return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
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void __exit ieee80211_crypto_ccmp_exit(void)
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ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);