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");
35 #define AES_BLOCK_LEN 16
36 #define CCMP_HDR_LEN 8
37 #define CCMP_MIC_LEN 8
38 #define CCMP_TK_LEN 16
41 struct ieee80211_ccmp_data {
45 u8 tx_pn[CCMP_PN_LEN];
46 u8 rx_pn[CCMP_PN_LEN];
48 u32 dot11RSNAStatsCCMPFormatErrors;
49 u32 dot11RSNAStatsCCMPReplays;
50 u32 dot11RSNAStatsCCMPDecryptErrors;
54 struct crypto_tfm *tfm;
56 /* scratch buffers for virt_to_page() (crypto API) */
57 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
58 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
59 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
62 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
63 const u8 pt[16], u8 ct[16])
65 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
68 static void * ieee80211_ccmp_init(int key_idx)
70 struct ieee80211_ccmp_data *priv;
72 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
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++)
115 static void ccmp_init_blocks(struct crypto_tfm *tfm,
116 struct ieee80211_hdr_4addr *hdr,
117 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
123 int a4_included, qc_included;
124 u8 aad[2 * AES_BLOCK_LEN];
126 fc = le16_to_cpu(hdr->frame_ctl);
127 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
128 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
130 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
131 (WLAN_FC_GET_STYPE(fc) & 0x08));
133 // fixed by David :2006.9.6
134 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
135 (WLAN_FC_GET_STYPE(fc) & 0x80));
140 pos = (u8 *) &hdr->addr4;
146 /* CCM Initial Block:
147 * Flag (Include authentication header, M=3 (8-octet MIC),
148 * L=1 (2-octet Dlen))
149 * Nonce: 0x00 | A2 | PN
153 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
154 memcpy(b0 + 8, pn, CCMP_PN_LEN);
155 b0[14] = (dlen >> 8) & 0xff;
156 b0[15] = dlen & 0xff;
159 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
161 * SC with bits 4..15 (seq#) masked to zero
166 aad[0] = 0; /* aad_len >> 8 */
167 aad[1] = aad_len & 0xff;
168 aad[2] = pos[0] & 0x8f;
169 aad[3] = pos[1] & 0xc7;
170 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
171 pos = (u8 *) &hdr->seq_ctl;
172 aad[22] = pos[0] & 0x0f;
173 aad[23] = 0; /* all bits masked */
174 memset(aad + 24, 0, 8);
176 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
178 aad[a4_included ? 30 : 24] = qc;
179 /* rest of QC masked */
182 /* Start with the first block and AAD */
183 ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
184 xor_block(auth, aad, AES_BLOCK_LEN);
185 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
186 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
187 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
190 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
193 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
195 struct ieee80211_ccmp_data *key = priv;
198 struct ieee80211_hdr_4addr *hdr;
199 int blocks, last, len;
206 if (skb_headroom(skb) < CCMP_HDR_LEN ||
207 skb_tailroom(skb) < CCMP_MIC_LEN ||
211 data_len = skb->len - hdr_len;
212 pos = skb_push(skb, CCMP_HDR_LEN);
213 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
215 // mic = skb_put(skb, CCMP_MIC_LEN);
220 if (key->tx_pn[i] != 0)
225 *pos++ = key->tx_pn[5];
226 *pos++ = key->tx_pn[4];
228 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
229 *pos++ = key->tx_pn[3];
230 *pos++ = key->tx_pn[2];
231 *pos++ = key->tx_pn[1];
232 *pos++ = key->tx_pn[0];
234 hdr = (struct ieee80211_hdr_4addr *)skb->data;
235 //mic is moved to here by john
236 mic = skb_put(skb, CCMP_MIC_LEN);
238 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
240 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
241 last = data_len % AES_BLOCK_LEN;
243 for (i = 1; i <= blocks; i++) {
244 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
246 xor_block(b, pos, len);
247 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
248 /* Encryption, with counter */
249 b0[14] = (i >> 8) & 0xff;
251 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
252 xor_block(pos, e, len);
256 for (i = 0; i < CCMP_MIC_LEN; i++)
257 mic[i] = b[i] ^ s0[i];
263 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
265 struct ieee80211_ccmp_data *key = priv;
267 struct ieee80211_hdr_4addr *hdr;
269 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
270 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
274 int i, blocks, last, len;
276 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
277 key->dot11RSNAStatsCCMPFormatErrors++;
281 hdr = (struct ieee80211_hdr_4addr *)skb->data;
282 pos = skb->data + hdr_len;
284 if (!(keyidx & (1 << 5))) {
285 if (net_ratelimit()) {
286 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
287 " flag from %pM\n", hdr->addr2);
289 key->dot11RSNAStatsCCMPFormatErrors++;
293 if (key->key_idx != keyidx) {
294 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
295 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
299 if (net_ratelimit()) {
300 printk(KERN_DEBUG "CCMP: received packet from %pM"
301 " with keyid=%d that does not have a configured"
302 " key\n", hdr->addr2, keyidx);
315 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
316 if (net_ratelimit()) {
317 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
318 " previous PN %pm received PN %pm\n",
319 hdr->addr2, key->rx_pn, pn);
321 key->dot11RSNAStatsCCMPReplays++;
325 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
326 xor_block(mic, b, CCMP_MIC_LEN);
328 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
329 last = data_len % AES_BLOCK_LEN;
331 for (i = 1; i <= blocks; i++) {
332 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
333 /* Decrypt, with counter */
334 b0[14] = (i >> 8) & 0xff;
336 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
337 xor_block(pos, b, len);
339 xor_block(a, pos, len);
340 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
344 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
345 if (net_ratelimit()) {
346 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
347 "%pM\n", hdr->addr2);
349 key->dot11RSNAStatsCCMPDecryptErrors++;
353 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
355 /* Remove hdr and MIC */
356 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
357 skb_pull(skb, CCMP_HDR_LEN);
358 skb_trim(skb, skb->len - CCMP_MIC_LEN);
364 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
366 struct ieee80211_ccmp_data *data = priv;
368 struct crypto_tfm *tfm = data->tfm;
370 keyidx = data->key_idx;
371 memset(data, 0, sizeof(*data));
372 data->key_idx = keyidx;
374 if (len == CCMP_TK_LEN) {
375 memcpy(data->key, key, CCMP_TK_LEN);
378 data->rx_pn[0] = seq[5];
379 data->rx_pn[1] = seq[4];
380 data->rx_pn[2] = seq[3];
381 data->rx_pn[3] = seq[2];
382 data->rx_pn[4] = seq[1];
383 data->rx_pn[5] = seq[0];
385 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
395 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
397 struct ieee80211_ccmp_data *data = priv;
399 if (len < CCMP_TK_LEN)
404 memcpy(key, data->key, CCMP_TK_LEN);
407 seq[0] = data->tx_pn[5];
408 seq[1] = data->tx_pn[4];
409 seq[2] = data->tx_pn[3];
410 seq[3] = data->tx_pn[2];
411 seq[4] = data->tx_pn[1];
412 seq[5] = data->tx_pn[0];
419 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
421 struct ieee80211_ccmp_data *ccmp = priv;
422 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
423 "tx_pn=%pm rx_pn=%pm "
424 "format_errors=%d replays=%d decrypt_errors=%d\n",
425 ccmp->key_idx, ccmp->key_set,
426 ccmp->tx_pn, ccmp->rx_pn,
427 ccmp->dot11RSNAStatsCCMPFormatErrors,
428 ccmp->dot11RSNAStatsCCMPReplays,
429 ccmp->dot11RSNAStatsCCMPDecryptErrors);
434 void ieee80211_ccmp_null(void)
436 // printk("============>%s()\n", __func__);
439 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
441 .init = ieee80211_ccmp_init,
442 .deinit = ieee80211_ccmp_deinit,
443 .encrypt_mpdu = ieee80211_ccmp_encrypt,
444 .decrypt_mpdu = ieee80211_ccmp_decrypt,
445 .encrypt_msdu = NULL,
446 .decrypt_msdu = NULL,
447 .set_key = ieee80211_ccmp_set_key,
448 .get_key = ieee80211_ccmp_get_key,
449 .print_stats = ieee80211_ccmp_print_stats,
450 .extra_prefix_len = CCMP_HDR_LEN,
451 .extra_postfix_len = CCMP_MIC_LEN,
452 .owner = THIS_MODULE,
456 int ieee80211_crypto_ccmp_init(void)
458 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
462 void ieee80211_crypto_ccmp_exit(void)
464 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);