linux/net/ieee80211/ieee80211_crypt_ccmp.c
Herbert Xu f12cc2090d [CRYPTO] users: Use block ciphers where applicable
This patch converts all remaining users to use the new block cipher type
where applicable.  It also changes all simple cipher operations to use
the new encrypt_one/decrypt_one interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2006-09-21 11:46:15 +10:00

465 lines
11 KiB
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/err.h>
#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 <asm/string.h>
#include <linux/wireless.h>
#include <net/ieee80211.h>
#include <linux/crypto.h>
#include <asm/scatterlist.h>
MODULE_AUTHOR("Jouni Malinen");
MODULE_DESCRIPTION("Host AP crypt: CCMP");
MODULE_LICENSE("GPL");
#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 ieee80211_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_cipher *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 inline void ieee80211_ccmp_aes_encrypt(struct crypto_cipher *tfm,
const u8 pt[16], u8 ct[16])
{
crypto_cipher_encrypt_one(tfm, ct, pt);
}
static void *ieee80211_ccmp_init(int key_idx)
{
struct ieee80211_ccmp_data *priv;
priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
if (priv == NULL)
goto fail;
priv->key_idx = key_idx;
priv->tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(priv->tfm)) {
printk(KERN_DEBUG "ieee80211_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(priv->tfm);
kfree(priv);
}
return NULL;
}
static void ieee80211_ccmp_deinit(void *priv)
{
struct ieee80211_ccmp_data *_priv = priv;
if (_priv && _priv->tfm)
crypto_free_cipher(_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_cipher *tfm,
struct ieee80211_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 & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
(WLAN_FC_GET_STYPE(fc) & IEEE80211_STYPE_QOS_DATA));
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 */
ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
xor_block(auth, aad, AES_BLOCK_LEN);
ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
b0[0] &= 0x07;
b0[14] = b0[15] = 0;
ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
}
static int ieee80211_ccmp_hdr(struct sk_buff *skb, int hdr_len,
u8 *aeskey, int keylen, void *priv)
{
struct ieee80211_ccmp_data *key = priv;
int i;
u8 *pos;
if (skb_headroom(skb) < CCMP_HDR_LEN || skb->len < hdr_len)
return -1;
if (aeskey != NULL && keylen >= CCMP_TK_LEN)
memcpy(aeskey, key->key, CCMP_TK_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];
return CCMP_HDR_LEN;
}
static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
struct ieee80211_ccmp_data *key = priv;
int data_len, i, blocks, last, len;
u8 *pos, *mic;
struct ieee80211_hdr_4addr *hdr;
u8 *b0 = key->tx_b0;
u8 *b = key->tx_b;
u8 *e = key->tx_e;
u8 *s0 = key->tx_s0;
if (skb_tailroom(skb) < CCMP_MIC_LEN || skb->len < hdr_len)
return -1;
data_len = skb->len - hdr_len;
len = ieee80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv);
if (len < 0)
return -1;
pos = skb->data + hdr_len + CCMP_HDR_LEN;
mic = skb_put(skb, CCMP_MIC_LEN);
hdr = (struct ieee80211_hdr_4addr *)skb->data;
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);
ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
/* Encryption, with counter */
b0[14] = (i >> 8) & 0xff;
b0[15] = i & 0xff;
ieee80211_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 ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
{
struct ieee80211_ccmp_data *key = priv;
u8 keyidx, *pos;
struct ieee80211_hdr_4addr *hdr;
u8 *b0 = key->rx_b0;
u8 *b = key->rx_b;
u8 *a = key->rx_a;
u8 pn[6];
int i, blocks, last, len;
size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
key->dot11RSNAStatsCCMPFormatErrors++;
return -1;
}
hdr = (struct ieee80211_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 " MAC_FMT "\n", MAC_ARG(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 " MAC_FMT
" with keyid=%d that does not have a configured"
" key\n", MAC_ARG(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) {
if (net_ratelimit()) {
printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
" previous PN %02x%02x%02x%02x%02x%02x "
"received PN %02x%02x%02x%02x%02x%02x\n",
MAC_ARG(hdr->addr2), MAC_ARG(key->rx_pn),
MAC_ARG(pn));
}
key->dot11RSNAStatsCCMPReplays++;
return -4;
}
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;
ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
xor_block(pos, b, len);
/* Authentication */
xor_block(a, pos, len);
ieee80211_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="
MAC_FMT "\n", MAC_ARG(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 ieee80211_ccmp_set_key(void *key, int len, u8 * seq, void *priv)
{
struct ieee80211_ccmp_data *data = priv;
int keyidx;
struct crypto_cipher *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(data->tfm, data->key, CCMP_TK_LEN);
} else if (len == 0)
data->key_set = 0;
else
return -1;
return 0;
}
static int ieee80211_ccmp_get_key(void *key, int len, u8 * seq, void *priv)
{
struct ieee80211_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 char *ieee80211_ccmp_print_stats(char *p, void *priv)
{
struct ieee80211_ccmp_data *ccmp = priv;
p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
"tx_pn=%02x%02x%02x%02x%02x%02x "
"rx_pn=%02x%02x%02x%02x%02x%02x "
"format_errors=%d replays=%d decrypt_errors=%d\n",
ccmp->key_idx, ccmp->key_set,
MAC_ARG(ccmp->tx_pn), MAC_ARG(ccmp->rx_pn),
ccmp->dot11RSNAStatsCCMPFormatErrors,
ccmp->dot11RSNAStatsCCMPReplays,
ccmp->dot11RSNAStatsCCMPDecryptErrors);
return p;
}
static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
.name = "CCMP",
.init = ieee80211_ccmp_init,
.deinit = ieee80211_ccmp_deinit,
.build_iv = ieee80211_ccmp_hdr,
.encrypt_mpdu = ieee80211_ccmp_encrypt,
.decrypt_mpdu = ieee80211_ccmp_decrypt,
.encrypt_msdu = NULL,
.decrypt_msdu = NULL,
.set_key = ieee80211_ccmp_set_key,
.get_key = ieee80211_ccmp_get_key,
.print_stats = ieee80211_ccmp_print_stats,
.extra_mpdu_prefix_len = CCMP_HDR_LEN,
.extra_mpdu_postfix_len = CCMP_MIC_LEN,
.owner = THIS_MODULE,
};
static int __init ieee80211_crypto_ccmp_init(void)
{
return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
}
static void __exit ieee80211_crypto_ccmp_exit(void)
{
ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
}
module_init(ieee80211_crypto_ccmp_init);
module_exit(ieee80211_crypto_ccmp_exit);