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/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/random.h>
17 #include <linux/skbuff.h>
18 #include <linux/netdevice.h>
19 #include <linux/if_ether.h>
20 #include <linux/if_arp.h>
21 #include <asm/string.h>
22 #include <linux/wireless.h>
24 #include "ieee80211.h"
26 #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 OPENSUSE_SLED 0
38 #define AES_BLOCK_LEN 16
39 #define CCMP_HDR_LEN 8
40 #define CCMP_MIC_LEN 8
41 #define CCMP_TK_LEN 16
44 struct ieee80211_ccmp_data {
48 u8 tx_pn[CCMP_PN_LEN];
49 u8 rx_pn[CCMP_PN_LEN];
51 u32 dot11RSNAStatsCCMPFormatErrors;
52 u32 dot11RSNAStatsCCMPReplays;
53 u32 dot11RSNAStatsCCMPDecryptErrors;
57 struct crypto_tfm *tfm;
59 /* scratch buffers for virt_to_page() (crypto API) */
60 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
61 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
62 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
65 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
66 const u8 pt[16], u8 ct[16])
68 crypto_cipher_encrypt_one((void*)tfm, ct, pt);
71 static void * ieee80211_ccmp_init(int key_idx)
73 struct ieee80211_ccmp_data *priv;
75 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
78 priv->key_idx = key_idx;
80 priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
81 if (IS_ERR(priv->tfm)) {
82 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
92 crypto_free_cipher((void*)priv->tfm);
100 static void ieee80211_ccmp_deinit(void *priv)
102 struct ieee80211_ccmp_data *_priv = priv;
103 if (_priv && _priv->tfm)
104 crypto_free_cipher((void*)_priv->tfm);
109 static inline void xor_block(u8 *b, u8 *a, size_t len)
112 for (i = 0; i < len; i++)
118 static void ccmp_init_blocks(struct crypto_tfm *tfm,
119 struct ieee80211_hdr_4addr *hdr,
120 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
126 int a4_included, qc_included;
127 u8 aad[2 * AES_BLOCK_LEN];
129 fc = le16_to_cpu(hdr->frame_ctl);
130 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
131 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
133 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
134 (WLAN_FC_GET_STYPE(fc) & 0x08));
136 // fixed by David :2006.9.6
137 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
138 (WLAN_FC_GET_STYPE(fc) & 0x80));
143 pos = (u8 *) &hdr->addr4;
149 /* CCM Initial Block:
150 * Flag (Include authentication header, M=3 (8-octet MIC),
151 * L=1 (2-octet Dlen))
152 * Nonce: 0x00 | A2 | PN
156 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
157 memcpy(b0 + 8, pn, CCMP_PN_LEN);
158 b0[14] = (dlen >> 8) & 0xff;
159 b0[15] = dlen & 0xff;
162 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
164 * SC with bits 4..15 (seq#) masked to zero
169 aad[0] = 0; /* aad_len >> 8 */
170 aad[1] = aad_len & 0xff;
171 aad[2] = pos[0] & 0x8f;
172 aad[3] = pos[1] & 0xc7;
173 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
174 pos = (u8 *) &hdr->seq_ctl;
175 aad[22] = pos[0] & 0x0f;
176 aad[23] = 0; /* all bits masked */
177 memset(aad + 24, 0, 8);
179 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
181 aad[a4_included ? 30 : 24] = qc;
182 /* rest of QC masked */
185 /* Start with the first block and AAD */
186 ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
187 xor_block(auth, aad, AES_BLOCK_LEN);
188 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
189 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
190 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
193 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
198 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
200 struct ieee80211_ccmp_data *key = priv;
203 struct ieee80211_hdr_4addr *hdr;
204 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
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];
235 hdr = (struct ieee80211_hdr_4addr *) skb->data;
236 if (!tcb_desc->bHwSec)
238 int blocks, last, len;
245 //mic is moved to here by john
246 mic = skb_put(skb, CCMP_MIC_LEN);
248 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
250 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
251 last = data_len % AES_BLOCK_LEN;
253 for (i = 1; i <= blocks; i++) {
254 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
256 xor_block(b, pos, len);
257 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
258 /* Encryption, with counter */
259 b0[14] = (i >> 8) & 0xff;
261 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
262 xor_block(pos, e, len);
266 for (i = 0; i < CCMP_MIC_LEN; i++)
267 mic[i] = b[i] ^ s0[i];
273 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
275 struct ieee80211_ccmp_data *key = priv;
277 struct ieee80211_hdr_4addr *hdr;
278 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
281 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
282 key->dot11RSNAStatsCCMPFormatErrors++;
286 hdr = (struct ieee80211_hdr_4addr *) skb->data;
287 pos = skb->data + hdr_len;
289 if (!(keyidx & (1 << 5))) {
290 if (net_ratelimit()) {
291 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
292 " flag from %pM\n", hdr->addr2);
294 key->dot11RSNAStatsCCMPFormatErrors++;
298 if (key->key_idx != keyidx) {
299 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
300 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
304 if (net_ratelimit()) {
305 printk(KERN_DEBUG "CCMP: received packet from %pM"
306 " with keyid=%d that does not have a configured"
307 " key\n", hdr->addr2, keyidx);
320 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
321 key->dot11RSNAStatsCCMPReplays++;
324 if (!tcb_desc->bHwSec)
326 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
327 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
331 int i, blocks, last, len;
334 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
335 xor_block(mic, b, CCMP_MIC_LEN);
337 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
338 last = data_len % AES_BLOCK_LEN;
340 for (i = 1; i <= blocks; i++) {
341 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
342 /* Decrypt, with counter */
343 b0[14] = (i >> 8) & 0xff;
345 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
346 xor_block(pos, b, len);
348 xor_block(a, pos, len);
349 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
353 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
354 if (net_ratelimit()) {
355 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
356 "%pM\n", hdr->addr2);
358 key->dot11RSNAStatsCCMPDecryptErrors++;
362 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
364 /* Remove hdr and MIC */
365 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
366 skb_pull(skb, CCMP_HDR_LEN);
367 skb_trim(skb, skb->len - CCMP_MIC_LEN);
373 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
375 struct ieee80211_ccmp_data *data = priv;
377 struct crypto_tfm *tfm = data->tfm;
379 keyidx = data->key_idx;
380 memset(data, 0, sizeof(*data));
381 data->key_idx = keyidx;
383 if (len == CCMP_TK_LEN) {
384 memcpy(data->key, key, CCMP_TK_LEN);
387 data->rx_pn[0] = seq[5];
388 data->rx_pn[1] = seq[4];
389 data->rx_pn[2] = seq[3];
390 data->rx_pn[3] = seq[2];
391 data->rx_pn[4] = seq[1];
392 data->rx_pn[5] = seq[0];
394 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN);
404 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
406 struct ieee80211_ccmp_data *data = priv;
408 if (len < CCMP_TK_LEN)
413 memcpy(key, data->key, CCMP_TK_LEN);
416 seq[0] = data->tx_pn[5];
417 seq[1] = data->tx_pn[4];
418 seq[2] = data->tx_pn[3];
419 seq[3] = data->tx_pn[2];
420 seq[4] = data->tx_pn[1];
421 seq[5] = data->tx_pn[0];
428 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
430 struct ieee80211_ccmp_data *ccmp = priv;
433 p += sprintf(p, "key[%d] alg=CCMP key_set=%d tx_pn=",
434 ccmp->key_idx, ccmp->key_set);
436 for (i = 0; i < ARRAY_SIZE(ccmp->tx_pn); i++)
437 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
439 sprintf(p, " rx_pn=");
440 for (i = 0; i < ARRAY_SIZE(ccmp->rx_pn); i++)
441 p += sprintf(p, "%02x", ccmp->tx_pn[i]);
443 p += sprintf(p, " format_errors=%d replays=%d decrypt_errors=%d\n",
444 ccmp->dot11RSNAStatsCCMPFormatErrors,
445 ccmp->dot11RSNAStatsCCMPReplays,
446 ccmp->dot11RSNAStatsCCMPDecryptErrors);
451 void ieee80211_ccmp_null(void)
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,
473 int __init ieee80211_crypto_ccmp_init(void)
475 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
479 void ieee80211_crypto_ccmp_exit(void)
481 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);