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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>
23
24#include "ieee80211.h"
25
26#include <linux/crypto.h>
27 #include <linux/scatterlist.h>
28
29MODULE_AUTHOR("Jouni Malinen");
30MODULE_DESCRIPTION("Host AP crypt: CCMP");
31MODULE_LICENSE("GPL");
32
33#define AES_BLOCK_LEN 16
34#define CCMP_HDR_LEN 8
35#define CCMP_MIC_LEN 8
36#define CCMP_TK_LEN 16
37#define CCMP_PN_LEN 6
38
39struct ieee80211_ccmp_data {
40 u8 key[CCMP_TK_LEN];
41 int key_set;
42
43 u8 tx_pn[CCMP_PN_LEN];
44 u8 rx_pn[CCMP_PN_LEN];
45
46 u32 dot11RSNAStatsCCMPFormatErrors;
47 u32 dot11RSNAStatsCCMPReplays;
48 u32 dot11RSNAStatsCCMPDecryptErrors;
49
50 int key_idx;
51
52 struct crypto_tfm *tfm;
53
54
55 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
56 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
57 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
58};
59
60void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
61 const u8 pt[16], u8 ct[16])
62{
63 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
64}
65
66static void *ieee80211_ccmp_init(int key_idx)
67{
68 struct ieee80211_ccmp_data *priv;
69
70 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
71 if (priv == NULL)
72 goto fail;
73 priv->key_idx = key_idx;
74
75 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
76 if (IS_ERR(priv->tfm)) {
77 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
78 "crypto API aes\n");
79 priv->tfm = NULL;
80 goto fail;
81 }
82
83 return priv;
84
85fail:
86 if (priv) {
87 if (priv->tfm)
88 crypto_free_cipher((void *)priv->tfm);
89 kfree(priv);
90 }
91
92 return NULL;
93}
94
95
96static void ieee80211_ccmp_deinit(void *priv)
97{
98 struct ieee80211_ccmp_data *_priv = priv;
99
100 if (_priv && _priv->tfm)
101 crypto_free_cipher((void *)_priv->tfm);
102 kfree(priv);
103}
104
105
106static inline void xor_block(u8 *b, u8 *a, size_t len)
107{
108 int i;
109 for (i = 0; i < len; i++)
110 b[i] ^= a[i];
111}
112
113
114
115static void ccmp_init_blocks(struct crypto_tfm *tfm,
116 struct ieee80211_hdr_4addr *hdr,
117 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
118 u8 *s0)
119{
120 u8 *pos, qc = 0;
121 size_t aad_len;
122 u16 fc;
123 int a4_included, qc_included;
124 u8 aad[2 * AES_BLOCK_LEN];
125
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));
129
130
131
132
133
134 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
135 (WLAN_FC_GET_STYPE(fc) & 0x80));
136 aad_len = 22;
137 if (a4_included)
138 aad_len += 6;
139 if (qc_included) {
140 pos = (u8 *) &hdr->addr4;
141 if (a4_included)
142 pos += 6;
143 qc = *pos & 0x0f;
144 aad_len += 2;
145 }
146
147
148
149
150
151 b0[0] = 0x59;
152 b0[1] = qc;
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;
157
158
159
160
161
162
163
164
165 pos = (u8 *) hdr;
166 aad[0] = 0;
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;
174 memset(aad + 24, 0, 8);
175 if (a4_included)
176 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
177 if (qc_included) {
178 aad[a4_included ? 30 : 24] = qc;
179
180 }
181
182
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);
188 b0[0] &= 0x07;
189 b0[14] = b0[15] = 0;
190 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
191}
192
193
194
195static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
196{
197 struct ieee80211_ccmp_data *key = priv;
198 int data_len, i;
199 u8 *pos;
200 struct ieee80211_hdr_4addr *hdr;
201 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
202
203 if (skb_headroom(skb) < CCMP_HDR_LEN ||
204 skb_tailroom(skb) < CCMP_MIC_LEN ||
205 skb->len < hdr_len)
206 return -1;
207
208 data_len = skb->len - hdr_len;
209 pos = skb_push(skb, CCMP_HDR_LEN);
210 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
211 pos += hdr_len;
212
213
214 i = CCMP_PN_LEN - 1;
215 while (i >= 0) {
216 key->tx_pn[i]++;
217 if (key->tx_pn[i] != 0)
218 break;
219 i--;
220 }
221
222 *pos++ = key->tx_pn[5];
223 *pos++ = key->tx_pn[4];
224 *pos++ = 0;
225 *pos++ = (key->key_idx << 6) | (1 << 5) ;
226 *pos++ = key->tx_pn[3];
227 *pos++ = key->tx_pn[2];
228 *pos++ = key->tx_pn[1];
229 *pos++ = key->tx_pn[0];
230
231
232 hdr = (struct ieee80211_hdr_4addr *) skb->data;
233 if (!tcb_desc->bHwSec)
234 {
235 int blocks, last, len;
236 u8 *mic;
237 u8 *b0 = key->tx_b0;
238 u8 *b = key->tx_b;
239 u8 *e = key->tx_e;
240 u8 *s0 = key->tx_s0;
241
242
243 mic = skb_put(skb, CCMP_MIC_LEN);
244
245 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
246
247 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
248 last = data_len % AES_BLOCK_LEN;
249
250 for (i = 1; i <= blocks; i++) {
251 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
252
253 xor_block(b, pos, len);
254 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
255
256 b0[14] = (i >> 8) & 0xff;
257 b0[15] = i & 0xff;
258 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
259 xor_block(pos, e, len);
260 pos += len;
261 }
262
263 for (i = 0; i < CCMP_MIC_LEN; i++)
264 mic[i] = b[i] ^ s0[i];
265 }
266 return 0;
267}
268
269
270static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
271{
272 struct ieee80211_ccmp_data *key = priv;
273 u8 keyidx, *pos;
274 struct ieee80211_hdr_4addr *hdr;
275 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
276 u8 pn[6];
277
278 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
279 key->dot11RSNAStatsCCMPFormatErrors++;
280 return -1;
281 }
282
283 hdr = (struct ieee80211_hdr_4addr *) skb->data;
284 pos = skb->data + hdr_len;
285 keyidx = pos[3];
286 if (!(keyidx & (1 << 5))) {
287 if (net_ratelimit()) {
288 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
289 " flag from %pM\n", hdr->addr2);
290 }
291 key->dot11RSNAStatsCCMPFormatErrors++;
292 return -2;
293 }
294 keyidx >>= 6;
295 if (key->key_idx != keyidx) {
296 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
297 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
298 return -6;
299 }
300 if (!key->key_set) {
301 if (net_ratelimit()) {
302 printk(KERN_DEBUG "CCMP: received packet from %pM"
303 " with keyid=%d that does not have a configured"
304 " key\n", hdr->addr2, keyidx);
305 }
306 return -3;
307 }
308
309 pn[0] = pos[7];
310 pn[1] = pos[6];
311 pn[2] = pos[5];
312 pn[3] = pos[4];
313 pn[4] = pos[1];
314 pn[5] = pos[0];
315 pos += 8;
316
317 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
318 if (net_ratelimit()) {
319 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
320 " previous PN %pm received PN %pm\n",
321 hdr->addr2, key->rx_pn, pn);
322 }
323 key->dot11RSNAStatsCCMPReplays++;
324 return -4;
325 }
326 if (!tcb_desc->bHwSec)
327 {
328 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
329 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
330 u8 *b0 = key->rx_b0;
331 u8 *b = key->rx_b;
332 u8 *a = key->rx_a;
333 int i, blocks, last, len;
334
335
336 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
337 xor_block(mic, b, CCMP_MIC_LEN);
338
339 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
340 last = data_len % AES_BLOCK_LEN;
341
342 for (i = 1; i <= blocks; i++) {
343 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
344
345 b0[14] = (i >> 8) & 0xff;
346 b0[15] = i & 0xff;
347 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
348 xor_block(pos, b, len);
349
350 xor_block(a, pos, len);
351 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
352 pos += len;
353 }
354
355 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
356 if (net_ratelimit()) {
357 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
358 "%pM\n", hdr->addr2);
359 }
360 key->dot11RSNAStatsCCMPDecryptErrors++;
361 return -5;
362 }
363
364 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
365 }
366
367 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
368 skb_pull(skb, CCMP_HDR_LEN);
369 skb_trim(skb, skb->len - CCMP_MIC_LEN);
370
371 return keyidx;
372}
373
374
375static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
376{
377 struct ieee80211_ccmp_data *data = priv;
378 int keyidx;
379 struct crypto_tfm *tfm = data->tfm;
380
381 keyidx = data->key_idx;
382 memset(data, 0, sizeof(*data));
383 data->key_idx = keyidx;
384 data->tfm = tfm;
385 if (len == CCMP_TK_LEN) {
386 memcpy(data->key, key, CCMP_TK_LEN);
387 data->key_set = 1;
388 if (seq) {
389 data->rx_pn[0] = seq[5];
390 data->rx_pn[1] = seq[4];
391 data->rx_pn[2] = seq[3];
392 data->rx_pn[3] = seq[2];
393 data->rx_pn[4] = seq[1];
394 data->rx_pn[5] = seq[0];
395 }
396 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
397 } else if (len == 0)
398 data->key_set = 0;
399 else
400 return -1;
401
402 return 0;
403}
404
405
406static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
407{
408 struct ieee80211_ccmp_data *data = priv;
409
410 if (len < CCMP_TK_LEN)
411 return -1;
412
413 if (!data->key_set)
414 return 0;
415 memcpy(key, data->key, CCMP_TK_LEN);
416
417 if (seq) {
418 seq[0] = data->tx_pn[5];
419 seq[1] = data->tx_pn[4];
420 seq[2] = data->tx_pn[3];
421 seq[3] = data->tx_pn[2];
422 seq[4] = data->tx_pn[1];
423 seq[5] = data->tx_pn[0];
424 }
425
426 return CCMP_TK_LEN;
427}
428
429
430static char *ieee80211_ccmp_print_stats(char *p, void *priv)
431{
432 struct ieee80211_ccmp_data *ccmp = priv;
433 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
434 "tx_pn=%pm rx_pn=%pm "
435 "format_errors=%d replays=%d decrypt_errors=%d\n",
436 ccmp->key_idx, ccmp->key_set,
437 ccmp->tx_pn, ccmp->rx_pn,
438 ccmp->dot11RSNAStatsCCMPFormatErrors,
439 ccmp->dot11RSNAStatsCCMPReplays,
440 ccmp->dot11RSNAStatsCCMPDecryptErrors);
441
442 return p;
443}
444
445void ieee80211_ccmp_null(void)
446{
447
448 return;
449}
450
451static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
452 .name = "CCMP",
453 .init = ieee80211_ccmp_init,
454 .deinit = ieee80211_ccmp_deinit,
455 .encrypt_mpdu = ieee80211_ccmp_encrypt,
456 .decrypt_mpdu = ieee80211_ccmp_decrypt,
457 .encrypt_msdu = NULL,
458 .decrypt_msdu = NULL,
459 .set_key = ieee80211_ccmp_set_key,
460 .get_key = ieee80211_ccmp_get_key,
461 .print_stats = ieee80211_ccmp_print_stats,
462 .extra_prefix_len = CCMP_HDR_LEN,
463 .extra_postfix_len = CCMP_MIC_LEN,
464 .owner = THIS_MODULE,
465};
466
467int __init ieee80211_crypto_ccmp_init(void)
468{
469 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
470}
471
472void __exit ieee80211_crypto_ccmp_exit(void)
473{
474 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
475}
476
