- 根目录:
- drivers
- staging
- rtl8192e
- rtllib_crypt_ccmp.c
/*
* Host AP crypt: host-based CCMP encryption implementation for Host AP driver
*
* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. See README and COPYING for
* more details.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <linux/string.h>
#include <linux/wireless.h>
#include "rtllib.h"
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#define AES_BLOCK_LEN 16
#define CCMP_HDR_LEN 8
#define CCMP_MIC_LEN 8
#define CCMP_TK_LEN 16
#define CCMP_PN_LEN 6
struct rtllib_ccmp_data {
u8 key[CCMP_TK_LEN];
int key_set;
u8 tx_pn[CCMP_PN_LEN];
u8 rx_pn[CCMP_PN_LEN];
u32 dot11RSNAStatsCCMPFormatErrors;
u32 dot11RSNAStatsCCMPReplays;
u32 dot11RSNAStatsCCMPDecryptErrors;
int key_idx;
struct crypto_tfm *tfm;
/* scratch buffers for virt_to_page() (crypto API) */
u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
};
static void rtllib_ccmp_aes_encrypt(struct crypto_tfm *tfm,
const u8 pt[16], u8 ct[16])
{
crypto_cipher_encrypt_one((void *)tfm, ct, pt);
}
static void *rtllib_ccmp_init(int key_idx)
{
struct rtllib_ccmp_data *priv;
priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
if (priv == NULL)
goto fail;
priv->key_idx = key_idx;
priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(priv->tfm)) {
printk(KERN_DEBUG "rtllib_crypt_ccmp: could not allocate "
"crypto API aes\n");
priv->tfm = NULL;
goto fail;
}
return priv;
fail:
if (priv) {
if (priv->tfm)
crypto_free_cipher((void *)priv->tfm);
kfree(priv);
}
return NULL;
}
static void rtllib_ccmp_deinit(void *priv)
{
struct rtllib_ccmp_data *_priv = priv;
if (_priv && _priv->tfm)
crypto_free_cipher((void *)_priv->tfm);
kfree(priv);
}
static inline void xor_block(u8 *b, u8 *a, size_t len)
{
int i;
for (i = 0; i < len; i++)
b[i] ^= a[i];
}
static void ccmp_init_blocks(struct crypto_tfm *tfm,
struct rtllib_hdr_4addr *hdr,
u8 *pn, size_t dlen, u8 *b0, u8 *auth,
u8 *s0)
{
u8 *pos, qc = 0;
size_t aad_len;
u16 fc;
int a4_included, qc_included;
u8 aad[2 * AES_BLOCK_LEN];
fc = le16_to_cpu(hdr->frame_ctl);
a4_included = ((fc & (RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS)) ==
(RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS));
/*
qc_included = ((WLAN_FC_GET_TYPE(fc) == RTLLIB_FTYPE_DATA) &&
(WLAN_FC_GET_STYPE(fc) & 0x08));
*/
qc_included = ((WLAN_FC_GET_TYPE(fc) == RTLLIB_FTYPE_DATA) &&
(WLAN_FC_GET_STYPE(fc) & 0x80));
aad_len = 22;
if (a4_included)
aad_len += 6;
if (qc_included) {
pos = (u8 *) &hdr->addr4;
if (a4_included)
pos += 6;
qc = *pos & 0x0f;
aad_len += 2;
}
/* CCM Initial Block:
* Flag (Include authentication header, M=3 (8-octet MIC),
* L=1 (2-octet Dlen))
* Nonce: 0x00 | A2 | PN
* Dlen */
b0[0] = 0x59;
b0[1] = qc;
memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
memcpy(b0 + 8, pn, CCMP_PN_LEN);
b0[14] = (dlen >> 8) & 0xff;
b0[15] = dlen & 0xff;
/* AAD:
* FC with bits 4..6 and 11..13 masked to zero; 14 is always one
* A1 | A2 | A3
* SC with bits 4..15 (seq#) masked to zero
* A4 (if present)
* QC (if present)
*/
pos = (u8 *) hdr;
aad[0] = 0; /* aad_len >> 8 */
aad[1] = aad_len & 0xff;
aad[2] = pos[0] & 0x8f;
aad[3] = pos[1] & 0xc7;
memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
pos = (u8 *) &hdr->seq_ctl;
aad[22] = pos[0] & 0x0f;
aad[23] = 0; /* all bits masked */
memset(aad + 24, 0, 8);
if (a4_included)
memcpy(aad + 24, hdr->addr4, ETH_ALEN);
if (qc_included) {
aad[a4_included ? 30 : 24] = qc;
/* rest of QC masked */
}
/* Start with the first block and AAD */
rtllib_ccmp_aes_encrypt(tfm, b0, auth);
xor_block(auth, aad, AES_BLOCK_LEN);
rtllib_ccmp_aes_encrypt(tfm, auth, auth);
xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
rtllib_ccmp_aes_encrypt(tfm, auth, auth);
b0[0] &= 0x07;
b0[14] = b0[15] = 0;
rtllib_ccmp_aes_encrypt(tfm, b0, s0);
}
static int rtllib_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
struct rtllib_ccmp_data *key = priv;
int data_len, i;
u8 *pos;
struct rtllib_hdr_4addr *hdr;
struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
MAX_DEV_ADDR_SIZE);
if (skb_headroom(skb) < CCMP_HDR_LEN ||
skb_tailroom(skb) < CCMP_MIC_LEN ||
skb->len < hdr_len)
return -1;
data_len = skb->len - hdr_len;
pos = skb_push(skb, CCMP_HDR_LEN);
memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
pos += hdr_len;
i = CCMP_PN_LEN - 1;
while (i >= 0) {
key->tx_pn[i]++;
if (key->tx_pn[i] != 0)
break;
i--;
}
*pos++ = key->tx_pn[5];
*pos++ = key->tx_pn[4];
*pos++ = 0;
*pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
*pos++ = key->tx_pn[3];
*pos++ = key->tx_pn[2];
*pos++ = key->tx_pn[1];
*pos++ = key->tx_pn[0];
hdr = (struct rtllib_hdr_4addr *) skb->data;
if (!tcb_desc->bHwSec) {
int blocks, last, len;
u8 *mic;
u8 *b0 = key->tx_b0;
u8 *b = key->tx_b;
u8 *e = key->tx_e;
u8 *s0 = key->tx_s0;
mic = skb_put(skb, CCMP_MIC_LEN);
ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len,
b0, b, s0);
blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
last = data_len % AES_BLOCK_LEN;
for (i = 1; i <= blocks; i++) {
len = (i == blocks && last) ? last : AES_BLOCK_LEN;
/* Authentication */
xor_block(b, pos, len);
rtllib_ccmp_aes_encrypt(key->tfm, b, b);
/* Encryption, with counter */
b0[14] = (i >> 8) & 0xff;
b0[15] = i & 0xff;
rtllib_ccmp_aes_encrypt(key->tfm, b0, e);
xor_block(pos, e, len);
pos += len;
}
for (i = 0; i < CCMP_MIC_LEN; i++)
mic[i] = b[i] ^ s0[i];
}
return 0;
}
static int rtllib_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
struct rtllib_ccmp_data *key = priv;
u8 keyidx, *pos;
struct rtllib_hdr_4addr *hdr;
struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
MAX_DEV_ADDR_SIZE);
u8 pn[6];
if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
key->dot11RSNAStatsCCMPFormatErrors++;
return -1;
}
hdr = (struct rtllib_hdr_4addr *) skb->data;
pos = skb->data + hdr_len;
keyidx = pos[3];
if (!(keyidx & (1 << 5))) {
if (net_ratelimit()) {
printk(KERN_DEBUG "CCMP: received packet without ExtIV"
" flag from %pM\n", hdr->addr2);
}
key->dot11RSNAStatsCCMPFormatErrors++;
return -2;
}
keyidx >>= 6;
if (key->key_idx != keyidx) {
printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
"keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
return -6;
}
if (!key->key_set) {
if (net_ratelimit()) {
printk(KERN_DEBUG "CCMP: received packet from %pM"
" with keyid=%d that does not have a configured"
" key\n", hdr->addr2, keyidx);
}
return -3;
}
pn[0] = pos[7];
pn[1] = pos[6];
pn[2] = pos[5];
pn[3] = pos[4];
pn[4] = pos[1];
pn[5] = pos[0];
pos += 8;
if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
key->dot11RSNAStatsCCMPReplays++;
return -4;
}
if (!tcb_desc->bHwSec) {
size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN -
CCMP_MIC_LEN;
u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
u8 *b0 = key->rx_b0;
u8 *b = key->rx_b;
u8 *a = key->rx_a;
int i, blocks, last, len;
ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
xor_block(mic, b, CCMP_MIC_LEN);
blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
last = data_len % AES_BLOCK_LEN;
for (i = 1; i <= blocks; i++) {
len = (i == blocks && last) ? last : AES_BLOCK_LEN;
/* Decrypt, with counter */
b0[14] = (i >> 8) & 0xff;
b0[15] = i & 0xff;
rtllib_ccmp_aes_encrypt(key->tfm, b0, b);
xor_block(pos, b, len);
/* Authentication */
xor_block(a, pos, len);
rtllib_ccmp_aes_encrypt(key->tfm, a, a);
pos += len;
}
if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
if (net_ratelimit()) {
printk(KERN_DEBUG "CCMP: decrypt failed: STA="
" %pM\n", hdr->addr2);
}
key->dot11RSNAStatsCCMPDecryptErrors++;
return -5;
}
memcpy(key->rx_pn, pn, CCMP_PN_LEN);
}
/* Remove hdr and MIC */
memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
skb_pull(skb, CCMP_HDR_LEN);
skb_trim(skb, skb->len - CCMP_MIC_LEN);
return keyidx;
}
static int rtllib_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
{
struct rtllib_ccmp_data *data = priv;
int keyidx;
struct crypto_tfm *tfm = data->tfm;
keyidx = data->key_idx;
memset(data, 0, sizeof(*data));
data->key_idx = keyidx;
data->tfm = tfm;
if (len == CCMP_TK_LEN) {
memcpy(data->key, key, CCMP_TK_LEN);
data->key_set = 1;
if (seq) {
data->rx_pn[0] = seq[5];
data->rx_pn[1] = seq[4];
data->rx_pn[2] = seq[3];
data->rx_pn[3] = seq[2];
data->rx_pn[4] = seq[1];
data->rx_pn[5] = seq[0];
}
crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
} else if (len == 0)
data->key_set = 0;
else
return -1;
return 0;
}
static int rtllib_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
{
struct rtllib_ccmp_data *data = priv;
if (len < CCMP_TK_LEN)
return -1;
if (!data->key_set)
return 0;
memcpy(key, data->key, CCMP_TK_LEN);
if (seq) {
seq[0] = data->tx_pn[5];
seq[1] = data->tx_pn[4];
seq[2] = data->tx_pn[3];
seq[3] = data->tx_pn[2];
seq[4] = data->tx_pn[1];
seq[5] = data->tx_pn[0];
}
return CCMP_TK_LEN;
}
static void rtllib_ccmp_print_stats(struct seq_file *m, void *priv)
{
struct rtllib_ccmp_data *ccmp = priv;
seq_printf(m,
"key[%d] alg=CCMP key_set=%d "
"tx_pn=%pM rx_pn=%pM "
"format_errors=%d replays=%d decrypt_errors=%d\n",
ccmp->key_idx, ccmp->key_set,
ccmp->tx_pn, ccmp->rx_pn,
ccmp->dot11RSNAStatsCCMPFormatErrors,
ccmp->dot11RSNAStatsCCMPReplays,
ccmp->dot11RSNAStatsCCMPDecryptErrors);
}
static struct lib80211_crypto_ops rtllib_crypt_ccmp = {
.name = "R-CCMP",
.init = rtllib_ccmp_init,
.deinit = rtllib_ccmp_deinit,
.encrypt_mpdu = rtllib_ccmp_encrypt,
.decrypt_mpdu = rtllib_ccmp_decrypt,
.encrypt_msdu = NULL,
.decrypt_msdu = NULL,
.set_key = rtllib_ccmp_set_key,
.get_key = rtllib_ccmp_get_key,
.print_stats = rtllib_ccmp_print_stats,
.extra_mpdu_prefix_len = CCMP_HDR_LEN,
.extra_mpdu_postfix_len = CCMP_MIC_LEN,
.owner = THIS_MODULE,
};
static int __init rtllib_crypto_ccmp_init(void)
{
return lib80211_register_crypto_ops(&rtllib_crypt_ccmp);
}
static void __exit rtllib_crypto_ccmp_exit(void)
{
lib80211_unregister_crypto_ops(&rtllib_crypt_ccmp);
}
module_init(rtllib_crypto_ccmp_init);
module_exit(rtllib_crypto_ccmp_exit);
MODULE_LICENSE("GPL");