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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>
24
25#include "ieee80211.h"
26
27#include <linux/crypto.h>
28#include <linux/scatterlist.h>
29
30MODULE_AUTHOR("Jouni Malinen");
31MODULE_DESCRIPTION("Host AP crypt: CCMP");
32MODULE_LICENSE("GPL");
33
34
35#define AES_BLOCK_LEN 16
36#define CCMP_HDR_LEN 8
37#define CCMP_MIC_LEN 8
38#define CCMP_TK_LEN 16
39#define CCMP_PN_LEN 6
40
41struct ieee80211_ccmp_data {
42 u8 key[CCMP_TK_LEN];
43 int key_set;
44
45 u8 tx_pn[CCMP_PN_LEN];
46 u8 rx_pn[CCMP_PN_LEN];
47
48 u32 dot11RSNAStatsCCMPFormatErrors;
49 u32 dot11RSNAStatsCCMPReplays;
50 u32 dot11RSNAStatsCCMPDecryptErrors;
51
52 int key_idx;
53
54 struct crypto_tfm *tfm;
55
56
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];
60};
61
62void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
63 const u8 pt[16], u8 ct[16])
64{
65 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
66}
67
68static void * ieee80211_ccmp_init(int key_idx)
69{
70 struct ieee80211_ccmp_data *priv;
71
72 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
73 if (priv == NULL)
74 goto fail;
75 priv->key_idx = key_idx;
76
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 "
80 "crypto API aes\n");
81 priv->tfm = NULL;
82 goto fail;
83 }
84
85 return priv;
86
87fail:
88 if (priv) {
89 if (priv->tfm)
90 crypto_free_cipher((void *)priv->tfm);
91 kfree(priv);
92 }
93
94 return NULL;
95}
96
97
98static void ieee80211_ccmp_deinit(void *priv)
99{
100 struct ieee80211_ccmp_data *_priv = priv;
101
102 if (_priv && _priv->tfm)
103 crypto_free_cipher((void *)_priv->tfm);
104 kfree(priv);
105}
106
107
108static inline void xor_block(u8 *b, u8 *a, size_t len)
109{
110 int i;
111 for (i = 0; i < len; i++)
112 b[i] ^= a[i];
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
193static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
194{
195 struct ieee80211_ccmp_data *key = priv;
196 int data_len, i;
197 u8 *pos;
198 struct ieee80211_hdr_4addr *hdr;
199 int blocks, last, len;
200 u8 *mic;
201 u8 *b0 = key->tx_b0;
202 u8 *b = key->tx_b;
203 u8 *e = key->tx_e;
204 u8 *s0 = key->tx_s0;
205
206 if (skb_headroom(skb) < CCMP_HDR_LEN ||
207 skb_tailroom(skb) < CCMP_MIC_LEN ||
208 skb->len < hdr_len)
209 return -1;
210
211 data_len = skb->len - hdr_len;
212 pos = skb_push(skb, CCMP_HDR_LEN);
213 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
214 pos += hdr_len;
215
216
217 i = CCMP_PN_LEN - 1;
218 while (i >= 0) {
219 key->tx_pn[i]++;
220 if (key->tx_pn[i] != 0)
221 break;
222 i--;
223 }
224
225 *pos++ = key->tx_pn[5];
226 *pos++ = key->tx_pn[4];
227 *pos++ = 0;
228 *pos++ = (key->key_idx << 6) | (1 << 5) ;
229 *pos++ = key->tx_pn[3];
230 *pos++ = key->tx_pn[2];
231 *pos++ = key->tx_pn[1];
232 *pos++ = key->tx_pn[0];
233
234 hdr = (struct ieee80211_hdr_4addr *)skb->data;
235
236 mic = skb_put(skb, CCMP_MIC_LEN);
237
238 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
239
240 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
241 last = data_len % AES_BLOCK_LEN;
242
243 for (i = 1; i <= blocks; i++) {
244 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
245
246 xor_block(b, pos, len);
247 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
248
249 b0[14] = (i >> 8) & 0xff;
250 b0[15] = i & 0xff;
251 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
252 xor_block(pos, e, len);
253 pos += len;
254 }
255
256 for (i = 0; i < CCMP_MIC_LEN; i++)
257 mic[i] = b[i] ^ s0[i];
258
259 return 0;
260}
261
262
263static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
264{
265 struct ieee80211_ccmp_data *key = priv;
266 u8 keyidx, *pos;
267 struct ieee80211_hdr_4addr *hdr;
268 u8 pn[6];
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;
271 u8 *b0 = key->rx_b0;
272 u8 *b = key->rx_b;
273 u8 *a = key->rx_a;
274 int i, blocks, last, len;
275
276 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
277 key->dot11RSNAStatsCCMPFormatErrors++;
278 return -1;
279 }
280
281 hdr = (struct ieee80211_hdr_4addr *)skb->data;
282 pos = skb->data + hdr_len;
283 keyidx = pos[3];
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);
288 }
289 key->dot11RSNAStatsCCMPFormatErrors++;
290 return -2;
291 }
292 keyidx >>= 6;
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);
296 return -6;
297 }
298 if (!key->key_set) {
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);
303 }
304 return -3;
305 }
306
307 pn[0] = pos[7];
308 pn[1] = pos[6];
309 pn[2] = pos[5];
310 pn[3] = pos[4];
311 pn[4] = pos[1];
312 pn[5] = pos[0];
313 pos += 8;
314
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);
320 }
321 key->dot11RSNAStatsCCMPReplays++;
322 return -4;
323 }
324
325 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
326 xor_block(mic, b, CCMP_MIC_LEN);
327
328 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
329 last = data_len % AES_BLOCK_LEN;
330
331 for (i = 1; i <= blocks; i++) {
332 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
333
334 b0[14] = (i >> 8) & 0xff;
335 b0[15] = i & 0xff;
336 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
337 xor_block(pos, b, len);
338
339 xor_block(a, pos, len);
340 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
341 pos += len;
342 }
343
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);
348 }
349 key->dot11RSNAStatsCCMPDecryptErrors++;
350 return -5;
351 }
352
353 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
354
355
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);
359
360 return keyidx;
361}
362
363
364static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
365{
366 struct ieee80211_ccmp_data *data = priv;
367 int keyidx;
368 struct crypto_tfm *tfm = data->tfm;
369
370 keyidx = data->key_idx;
371 memset(data, 0, sizeof(*data));
372 data->key_idx = keyidx;
373 data->tfm = tfm;
374 if (len == CCMP_TK_LEN) {
375 memcpy(data->key, key, CCMP_TK_LEN);
376 data->key_set = 1;
377 if (seq) {
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];
384 }
385 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
386 } else if (len == 0)
387 data->key_set = 0;
388 else
389 return -1;
390
391 return 0;
392}
393
394
395static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
396{
397 struct ieee80211_ccmp_data *data = priv;
398
399 if (len < CCMP_TK_LEN)
400 return -1;
401
402 if (!data->key_set)
403 return 0;
404 memcpy(key, data->key, CCMP_TK_LEN);
405
406 if (seq) {
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];
413 }
414
415 return CCMP_TK_LEN;
416}
417
418
419static char * ieee80211_ccmp_print_stats(char *p, void *priv)
420{
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);
430
431 return p;
432}
433
434void ieee80211_ccmp_null(void)
435{
436
437 return;
438}
439static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
440 .name = "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,
453};
454
455
456int ieee80211_crypto_ccmp_init(void)
457{
458 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
459}
460
461
462void ieee80211_crypto_ccmp_exit(void)
463{
464 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
465}
466
