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 = kzalloc(sizeof(*priv), GFP_ATOMIC);
74 priv->key_idx = key_idx;
76 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
77 if (IS_ERR(priv->tfm)) {
78 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
89 crypto_free_cipher((void*)priv->tfm);
97 static void ieee80211_ccmp_deinit(void *priv)
99 struct ieee80211_ccmp_data *_priv = priv;
101 if (_priv && _priv->tfm)
102 crypto_free_cipher((void*)_priv->tfm);
107 static inline void xor_block(u8 *b, u8 *a, size_t len)
110 for (i = 0; i < len; i++)
116 static void ccmp_init_blocks(struct crypto_tfm *tfm,
117 struct ieee80211_hdr_4addr *hdr,
118 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
124 int a4_included, qc_included;
125 u8 aad[2 * AES_BLOCK_LEN];
127 fc = le16_to_cpu(hdr->frame_ctl);
128 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
129 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
131 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
132 (WLAN_FC_GET_STYPE(fc) & 0x08));
134 // fixed by David :2006.9.6
135 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
136 (WLAN_FC_GET_STYPE(fc) & 0x80));
141 pos = (u8 *) &hdr->addr4;
147 /* CCM Initial Block:
148 * Flag (Include authentication header, M=3 (8-octet MIC),
149 * L=1 (2-octet Dlen))
150 * Nonce: 0x00 | A2 | PN
154 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
155 memcpy(b0 + 8, pn, CCMP_PN_LEN);
156 b0[14] = (dlen >> 8) & 0xff;
157 b0[15] = dlen & 0xff;
160 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
162 * SC with bits 4..15 (seq#) masked to zero
167 aad[0] = 0; /* aad_len >> 8 */
168 aad[1] = aad_len & 0xff;
169 aad[2] = pos[0] & 0x8f;
170 aad[3] = pos[1] & 0xc7;
171 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
172 pos = (u8 *) &hdr->seq_ctl;
173 aad[22] = pos[0] & 0x0f;
174 aad[23] = 0; /* all bits masked */
175 memset(aad + 24, 0, 8);
177 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
179 aad[a4_included ? 30 : 24] = qc;
180 /* rest of QC masked */
183 /* Start with the first block and AAD */
184 ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
185 xor_block(auth, aad, AES_BLOCK_LEN);
186 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
187 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
188 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
191 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
196 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
198 struct ieee80211_ccmp_data *key = priv;
201 struct ieee80211_hdr_4addr *hdr;
202 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
204 if (skb_headroom(skb) < CCMP_HDR_LEN ||
205 skb_tailroom(skb) < CCMP_MIC_LEN ||
209 data_len = skb->len - hdr_len;
210 pos = skb_push(skb, CCMP_HDR_LEN);
211 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
213 // mic = skb_put(skb, CCMP_MIC_LEN);
218 if (key->tx_pn[i] != 0)
223 *pos++ = key->tx_pn[5];
224 *pos++ = key->tx_pn[4];
226 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
227 *pos++ = key->tx_pn[3];
228 *pos++ = key->tx_pn[2];
229 *pos++ = key->tx_pn[1];
230 *pos++ = key->tx_pn[0];
233 hdr = (struct ieee80211_hdr_4addr *) skb->data;
234 if (!tcb_desc->bHwSec)
236 int blocks, last, len;
243 //mic is moved to here by john
244 mic = skb_put(skb, CCMP_MIC_LEN);
246 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
248 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
249 last = data_len % AES_BLOCK_LEN;
251 for (i = 1; i <= blocks; i++) {
252 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
254 xor_block(b, pos, len);
255 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
256 /* Encryption, with counter */
257 b0[14] = (i >> 8) & 0xff;
259 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
260 xor_block(pos, e, len);
264 for (i = 0; i < CCMP_MIC_LEN; i++)
265 mic[i] = b[i] ^ s0[i];
271 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
273 struct ieee80211_ccmp_data *key = priv;
275 struct ieee80211_hdr_4addr *hdr;
276 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
279 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
280 key->dot11RSNAStatsCCMPFormatErrors++;
284 hdr = (struct ieee80211_hdr_4addr *) skb->data;
285 pos = skb->data + hdr_len;
287 if (!(keyidx & (1 << 5))) {
288 if (net_ratelimit()) {
289 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
290 " flag from %pM\n", hdr->addr2);
292 key->dot11RSNAStatsCCMPFormatErrors++;
296 if (key->key_idx != keyidx) {
297 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
298 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
302 if (net_ratelimit()) {
303 printk(KERN_DEBUG "CCMP: received packet from %pM"
304 " with keyid=%d that does not have a configured"
305 " key\n", hdr->addr2, keyidx);
318 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
319 if (net_ratelimit()) {
320 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
321 " previous PN %pm received PN %pm\n",
322 hdr->addr2, key->rx_pn, pn);
324 key->dot11RSNAStatsCCMPReplays++;
327 if (!tcb_desc->bHwSec)
329 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
330 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
334 int i, blocks, last, len;
337 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
338 xor_block(mic, b, CCMP_MIC_LEN);
340 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
341 last = data_len % AES_BLOCK_LEN;
343 for (i = 1; i <= blocks; i++) {
344 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
345 /* Decrypt, with counter */
346 b0[14] = (i >> 8) & 0xff;
348 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
349 xor_block(pos, b, len);
351 xor_block(a, pos, len);
352 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
356 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
357 if (net_ratelimit()) {
358 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
359 "%pM\n", hdr->addr2);
361 key->dot11RSNAStatsCCMPDecryptErrors++;
365 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
367 /* Remove hdr and MIC */
368 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
369 skb_pull(skb, CCMP_HDR_LEN);
370 skb_trim(skb, skb->len - CCMP_MIC_LEN);
376 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
378 struct ieee80211_ccmp_data *data = priv;
380 struct crypto_tfm *tfm = data->tfm;
382 keyidx = data->key_idx;
383 memset(data, 0, sizeof(*data));
384 data->key_idx = keyidx;
386 if (len == CCMP_TK_LEN) {
387 memcpy(data->key, key, CCMP_TK_LEN);
390 data->rx_pn[0] = seq[5];
391 data->rx_pn[1] = seq[4];
392 data->rx_pn[2] = seq[3];
393 data->rx_pn[3] = seq[2];
394 data->rx_pn[4] = seq[1];
395 data->rx_pn[5] = seq[0];
397 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
407 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
409 struct ieee80211_ccmp_data *data = priv;
411 if (len < CCMP_TK_LEN)
416 memcpy(key, data->key, CCMP_TK_LEN);
419 seq[0] = data->tx_pn[5];
420 seq[1] = data->tx_pn[4];
421 seq[2] = data->tx_pn[3];
422 seq[3] = data->tx_pn[2];
423 seq[4] = data->tx_pn[1];
424 seq[5] = data->tx_pn[0];
431 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
433 struct ieee80211_ccmp_data *ccmp = priv;
434 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
435 "tx_pn=%pm rx_pn=%pm "
436 "format_errors=%d replays=%d decrypt_errors=%d\n",
437 ccmp->key_idx, ccmp->key_set,
438 ccmp->tx_pn, ccmp->rx_pn,
439 ccmp->dot11RSNAStatsCCMPFormatErrors,
440 ccmp->dot11RSNAStatsCCMPReplays,
441 ccmp->dot11RSNAStatsCCMPDecryptErrors);
446 void ieee80211_ccmp_null(void)
448 // printk("============>%s()\n", __FUNCTION__);
452 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
454 .init = ieee80211_ccmp_init,
455 .deinit = ieee80211_ccmp_deinit,
456 .encrypt_mpdu = ieee80211_ccmp_encrypt,
457 .decrypt_mpdu = ieee80211_ccmp_decrypt,
458 .encrypt_msdu = NULL,
459 .decrypt_msdu = NULL,
460 .set_key = ieee80211_ccmp_set_key,
461 .get_key = ieee80211_ccmp_get_key,
462 .print_stats = ieee80211_ccmp_print_stats,
463 .extra_prefix_len = CCMP_HDR_LEN,
464 .extra_postfix_len = CCMP_MIC_LEN,
465 .owner = THIS_MODULE,
468 int __init ieee80211_crypto_ccmp_init(void)
470 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
473 void __exit ieee80211_crypto_ccmp_exit(void)
475 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);