2 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
4 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation. See README and COPYING for
12 //#include <linux/config.h>
13 #include <linux/version.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/random.h>
18 #include <linux/skbuff.h>
19 #include <linux/netdevice.h>
20 #include <linux/if_ether.h>
21 #include <linux/if_arp.h>
22 #include <asm/string.h>
23 #include <linux/wireless.h>
25 #include "ieee80211.h"
27 #include <linux/crypto.h>
28 #include <linux/scatterlist.h>
30 MODULE_AUTHOR("Jouni Malinen");
31 MODULE_DESCRIPTION("Host AP crypt: CCMP");
32 MODULE_LICENSE("GPL");
34 #define AES_BLOCK_LEN 16
35 #define CCMP_HDR_LEN 8
36 #define CCMP_MIC_LEN 8
37 #define CCMP_TK_LEN 16
40 struct ieee80211_ccmp_data {
44 u8 tx_pn[CCMP_PN_LEN];
45 u8 rx_pn[CCMP_PN_LEN];
47 u32 dot11RSNAStatsCCMPFormatErrors;
48 u32 dot11RSNAStatsCCMPReplays;
49 u32 dot11RSNAStatsCCMPDecryptErrors;
53 struct crypto_tfm *tfm;
55 /* scratch buffers for virt_to_page() (crypto API) */
56 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
57 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
58 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
61 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
62 const u8 pt[16], u8 ct[16])
64 crypto_cipher_encrypt_one((void*)tfm, ct, pt);
67 static void * ieee80211_ccmp_init(int key_idx)
69 struct ieee80211_ccmp_data *priv;
71 priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
74 memset(priv, 0, sizeof(*priv));
75 priv->key_idx = key_idx;
77 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
78 if (IS_ERR(priv->tfm)) {
79 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
90 crypto_free_cipher((void*)priv->tfm);
98 static void ieee80211_ccmp_deinit(void *priv)
100 struct ieee80211_ccmp_data *_priv = priv;
102 if (_priv && _priv->tfm)
103 crypto_free_cipher((void*)_priv->tfm);
108 static inline void xor_block(u8 *b, u8 *a, size_t len)
111 for (i = 0; i < len; i++)
117 static void ccmp_init_blocks(struct crypto_tfm *tfm,
118 struct ieee80211_hdr_4addr *hdr,
119 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
125 int a4_included, qc_included;
126 u8 aad[2 * AES_BLOCK_LEN];
128 fc = le16_to_cpu(hdr->frame_ctl);
129 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
130 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
132 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
133 (WLAN_FC_GET_STYPE(fc) & 0x08));
135 // fixed by David :2006.9.6
136 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
137 (WLAN_FC_GET_STYPE(fc) & 0x80));
142 pos = (u8 *) &hdr->addr4;
148 /* CCM Initial Block:
149 * Flag (Include authentication header, M=3 (8-octet MIC),
150 * L=1 (2-octet Dlen))
151 * Nonce: 0x00 | A2 | PN
155 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
156 memcpy(b0 + 8, pn, CCMP_PN_LEN);
157 b0[14] = (dlen >> 8) & 0xff;
158 b0[15] = dlen & 0xff;
161 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
163 * SC with bits 4..15 (seq#) masked to zero
168 aad[0] = 0; /* aad_len >> 8 */
169 aad[1] = aad_len & 0xff;
170 aad[2] = pos[0] & 0x8f;
171 aad[3] = pos[1] & 0xc7;
172 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
173 pos = (u8 *) &hdr->seq_ctl;
174 aad[22] = pos[0] & 0x0f;
175 aad[23] = 0; /* all bits masked */
176 memset(aad + 24, 0, 8);
178 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
180 aad[a4_included ? 30 : 24] = qc;
181 /* rest of QC masked */
184 /* Start with the first block and AAD */
185 ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
186 xor_block(auth, aad, AES_BLOCK_LEN);
187 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
188 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
189 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
192 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
197 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
199 struct ieee80211_ccmp_data *key = priv;
202 struct ieee80211_hdr_4addr *hdr;
203 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
205 if (skb_headroom(skb) < CCMP_HDR_LEN ||
206 skb_tailroom(skb) < CCMP_MIC_LEN ||
210 data_len = skb->len - hdr_len;
211 pos = skb_push(skb, CCMP_HDR_LEN);
212 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
214 // mic = skb_put(skb, CCMP_MIC_LEN);
219 if (key->tx_pn[i] != 0)
224 *pos++ = key->tx_pn[5];
225 *pos++ = key->tx_pn[4];
227 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
228 *pos++ = key->tx_pn[3];
229 *pos++ = key->tx_pn[2];
230 *pos++ = key->tx_pn[1];
231 *pos++ = key->tx_pn[0];
234 hdr = (struct ieee80211_hdr_4addr *) skb->data;
235 if (!tcb_desc->bHwSec)
237 int blocks, last, len;
244 //mic is moved to here by john
245 mic = skb_put(skb, CCMP_MIC_LEN);
247 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
249 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
250 last = data_len % AES_BLOCK_LEN;
252 for (i = 1; i <= blocks; i++) {
253 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
255 xor_block(b, pos, len);
256 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
257 /* Encryption, with counter */
258 b0[14] = (i >> 8) & 0xff;
260 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
261 xor_block(pos, e, len);
265 for (i = 0; i < CCMP_MIC_LEN; i++)
266 mic[i] = b[i] ^ s0[i];
272 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
274 struct ieee80211_ccmp_data *key = priv;
276 struct ieee80211_hdr_4addr *hdr;
277 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
280 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
281 key->dot11RSNAStatsCCMPFormatErrors++;
285 hdr = (struct ieee80211_hdr_4addr *) skb->data;
286 pos = skb->data + hdr_len;
288 if (!(keyidx & (1 << 5))) {
289 if (net_ratelimit()) {
290 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
291 " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
293 key->dot11RSNAStatsCCMPFormatErrors++;
297 if (key->key_idx != keyidx) {
298 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
299 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
303 if (net_ratelimit()) {
304 printk(KERN_DEBUG "CCMP: received packet from " MAC_FMT
305 " with keyid=%d that does not have a configured"
306 " key\n", MAC_ARG(hdr->addr2), keyidx);
319 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
320 if (net_ratelimit()) {
321 printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
322 " previous PN %02x%02x%02x%02x%02x%02x "
323 "received PN %02x%02x%02x%02x%02x%02x\n",
324 MAC_ARG(hdr->addr2), MAC_ARG(key->rx_pn),
327 key->dot11RSNAStatsCCMPReplays++;
330 if (!tcb_desc->bHwSec)
332 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
333 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
337 int i, blocks, last, len;
340 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
341 xor_block(mic, b, CCMP_MIC_LEN);
343 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
344 last = data_len % AES_BLOCK_LEN;
346 for (i = 1; i <= blocks; i++) {
347 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
348 /* Decrypt, with counter */
349 b0[14] = (i >> 8) & 0xff;
351 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
352 xor_block(pos, b, len);
354 xor_block(a, pos, len);
355 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
359 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
360 if (net_ratelimit()) {
361 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
362 MAC_FMT "\n", MAC_ARG(hdr->addr2));
364 key->dot11RSNAStatsCCMPDecryptErrors++;
368 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
370 /* Remove hdr and MIC */
371 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
372 skb_pull(skb, CCMP_HDR_LEN);
373 skb_trim(skb, skb->len - CCMP_MIC_LEN);
379 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
381 struct ieee80211_ccmp_data *data = priv;
383 struct crypto_tfm *tfm = data->tfm;
385 keyidx = data->key_idx;
386 memset(data, 0, sizeof(*data));
387 data->key_idx = keyidx;
389 if (len == CCMP_TK_LEN) {
390 memcpy(data->key, key, CCMP_TK_LEN);
393 data->rx_pn[0] = seq[5];
394 data->rx_pn[1] = seq[4];
395 data->rx_pn[2] = seq[3];
396 data->rx_pn[3] = seq[2];
397 data->rx_pn[4] = seq[1];
398 data->rx_pn[5] = seq[0];
400 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
410 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
412 struct ieee80211_ccmp_data *data = priv;
414 if (len < CCMP_TK_LEN)
419 memcpy(key, data->key, CCMP_TK_LEN);
422 seq[0] = data->tx_pn[5];
423 seq[1] = data->tx_pn[4];
424 seq[2] = data->tx_pn[3];
425 seq[3] = data->tx_pn[2];
426 seq[4] = data->tx_pn[1];
427 seq[5] = data->tx_pn[0];
434 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
436 struct ieee80211_ccmp_data *ccmp = priv;
437 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
438 "tx_pn=%02x%02x%02x%02x%02x%02x "
439 "rx_pn=%02x%02x%02x%02x%02x%02x "
440 "format_errors=%d replays=%d decrypt_errors=%d\n",
441 ccmp->key_idx, ccmp->key_set,
442 MAC_ARG(ccmp->tx_pn), MAC_ARG(ccmp->rx_pn),
443 ccmp->dot11RSNAStatsCCMPFormatErrors,
444 ccmp->dot11RSNAStatsCCMPReplays,
445 ccmp->dot11RSNAStatsCCMPDecryptErrors);
450 void ieee80211_ccmp_null(void)
452 // printk("============>%s()\n", __FUNCTION__);
456 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
458 .init = ieee80211_ccmp_init,
459 .deinit = ieee80211_ccmp_deinit,
460 .encrypt_mpdu = ieee80211_ccmp_encrypt,
461 .decrypt_mpdu = ieee80211_ccmp_decrypt,
462 .encrypt_msdu = NULL,
463 .decrypt_msdu = NULL,
464 .set_key = ieee80211_ccmp_set_key,
465 .get_key = ieee80211_ccmp_get_key,
466 .print_stats = ieee80211_ccmp_print_stats,
467 .extra_prefix_len = CCMP_HDR_LEN,
468 .extra_postfix_len = CCMP_MIC_LEN,
469 .owner = THIS_MODULE,
472 int __init ieee80211_crypto_ccmp_init(void)
474 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
477 void __exit ieee80211_crypto_ccmp_exit(void)
479 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);