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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 = kmalloc(sizeof(*priv), GFP_ATOMIC);
73 if (priv == NULL)
74 goto fail;
75 memset(priv, 0, sizeof(*priv));
76 priv->key_idx = key_idx;
77
78 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
79 if (IS_ERR(priv->tfm)) {
80 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
81 "crypto API aes\n");
82 priv->tfm = NULL;
83 goto fail;
84 }
85
86 return priv;
87
88fail:
89 if (priv) {
90 if (priv->tfm)
91 crypto_free_cipher((void *)priv->tfm);
92 kfree(priv);
93 }
94
95 return NULL;
96}
97
98
99static void ieee80211_ccmp_deinit(void *priv)
100{
101 struct ieee80211_ccmp_data *_priv = priv;
102
103 if (_priv && _priv->tfm)
104 crypto_free_cipher((void *)_priv->tfm);
105 kfree(priv);
106}
107
108
109static inline void xor_block(u8 *b, u8 *a, size_t len)
110{
111 int i;
112 for (i = 0; i < len; i++)
113 b[i] ^= a[i];
114}
115
116static void ccmp_init_blocks(struct crypto_tfm *tfm,
117 struct ieee80211_hdr_4addr *hdr,
118 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
119 u8 *s0)
120{
121 u8 *pos, qc = 0;
122 size_t aad_len;
123 u16 fc;
124 int a4_included, qc_included;
125 u8 aad[2 * AES_BLOCK_LEN];
126
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));
130
131
132
133
134
135 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
136 (WLAN_FC_GET_STYPE(fc) & 0x80));
137 aad_len = 22;
138 if (a4_included)
139 aad_len += 6;
140 if (qc_included) {
141 pos = (u8 *) &hdr->addr4;
142 if (a4_included)
143 pos += 6;
144 qc = *pos & 0x0f;
145 aad_len += 2;
146 }
147
148
149
150
151
152 b0[0] = 0x59;
153 b0[1] = qc;
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;
158
159
160
161
162
163
164
165
166 pos = (u8 *) hdr;
167 aad[0] = 0;
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;
175 memset(aad + 24, 0, 8);
176 if (a4_included)
177 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
178 if (qc_included) {
179 aad[a4_included ? 30 : 24] = qc;
180
181 }
182
183
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);
189 b0[0] &= 0x07;
190 b0[14] = b0[15] = 0;
191 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
192}
193
194static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
195{
196 struct ieee80211_ccmp_data *key = priv;
197 int data_len, i;
198 u8 *pos;
199 struct ieee80211_hdr_4addr *hdr;
200 int blocks, last, len;
201 u8 *mic;
202 u8 *b0 = key->tx_b0;
203 u8 *b = key->tx_b;
204 u8 *e = key->tx_e;
205 u8 *s0 = key->tx_s0;
206
207 if (skb_headroom(skb) < CCMP_HDR_LEN ||
208 skb_tailroom(skb) < CCMP_MIC_LEN ||
209 skb->len < hdr_len)
210 return -1;
211
212 data_len = skb->len - hdr_len;
213 pos = skb_push(skb, CCMP_HDR_LEN);
214 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
215 pos += hdr_len;
216
217
218 i = CCMP_PN_LEN - 1;
219 while (i >= 0) {
220 key->tx_pn[i]++;
221 if (key->tx_pn[i] != 0)
222 break;
223 i--;
224 }
225
226 *pos++ = key->tx_pn[5];
227 *pos++ = key->tx_pn[4];
228 *pos++ = 0;
229 *pos++ = (key->key_idx << 6) | (1 << 5) ;
230 *pos++ = key->tx_pn[3];
231 *pos++ = key->tx_pn[2];
232 *pos++ = key->tx_pn[1];
233 *pos++ = key->tx_pn[0];
234
235 hdr = (struct ieee80211_hdr_4addr *)skb->data;
236
237 mic = skb_put(skb, CCMP_MIC_LEN);
238
239 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
240
241 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
242 last = data_len % AES_BLOCK_LEN;
243
244 for (i = 1; i <= blocks; i++) {
245 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
246
247 xor_block(b, pos, len);
248 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
249
250 b0[14] = (i >> 8) & 0xff;
251 b0[15] = i & 0xff;
252 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
253 xor_block(pos, e, len);
254 pos += len;
255 }
256
257 for (i = 0; i < CCMP_MIC_LEN; i++)
258 mic[i] = b[i] ^ s0[i];
259
260 return 0;
261}
262
263
264static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
265{
266 struct ieee80211_ccmp_data *key = priv;
267 u8 keyidx, *pos;
268 struct ieee80211_hdr_4addr *hdr;
269 u8 pn[6];
270 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
271 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
272 u8 *b0 = key->rx_b0;
273 u8 *b = key->rx_b;
274 u8 *a = key->rx_a;
275 int i, blocks, last, len;
276
277 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
278 key->dot11RSNAStatsCCMPFormatErrors++;
279 return -1;
280 }
281
282 hdr = (struct ieee80211_hdr_4addr *)skb->data;
283 pos = skb->data + hdr_len;
284 keyidx = pos[3];
285 if (!(keyidx & (1 << 5))) {
286 if (net_ratelimit()) {
287 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
288 " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
289 }
290 key->dot11RSNAStatsCCMPFormatErrors++;
291 return -2;
292 }
293 keyidx >>= 6;
294 if (key->key_idx != keyidx) {
295 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
296 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
297 return -6;
298 }
299 if (!key->key_set) {
300 if (net_ratelimit()) {
301 printk(KERN_DEBUG "CCMP: received packet from " MAC_FMT
302 " with keyid=%d that does not have a configured"
303 " key\n", MAC_ARG(hdr->addr2), keyidx);
304 }
305 return -3;
306 }
307
308 pn[0] = pos[7];
309 pn[1] = pos[6];
310 pn[2] = pos[5];
311 pn[3] = pos[4];
312 pn[4] = pos[1];
313 pn[5] = pos[0];
314 pos += 8;
315
316 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
317 if (net_ratelimit()) {
318 printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
319 " previous PN %02x%02x%02x%02x%02x%02x "
320 "received PN %02x%02x%02x%02x%02x%02x\n",
321 MAC_ARG(hdr->addr2), MAC_ARG(key->rx_pn),
322 MAC_ARG(pn));
323 }
324 key->dot11RSNAStatsCCMPReplays++;
325 return -4;
326 }
327
328 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
329 xor_block(mic, b, CCMP_MIC_LEN);
330
331 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
332 last = data_len % AES_BLOCK_LEN;
333
334 for (i = 1; i <= blocks; i++) {
335 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
336
337 b0[14] = (i >> 8) & 0xff;
338 b0[15] = i & 0xff;
339 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
340 xor_block(pos, b, len);
341
342 xor_block(a, pos, len);
343 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
344 pos += len;
345 }
346
347 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
348 if (net_ratelimit()) {
349 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
350 MAC_FMT "\n", MAC_ARG(hdr->addr2));
351 }
352 key->dot11RSNAStatsCCMPDecryptErrors++;
353 return -5;
354 }
355
356 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
357
358
359 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
360 skb_pull(skb, CCMP_HDR_LEN);
361 skb_trim(skb, skb->len - CCMP_MIC_LEN);
362
363 return keyidx;
364}
365
366
367static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
368{
369 struct ieee80211_ccmp_data *data = priv;
370 int keyidx;
371 struct crypto_tfm *tfm = data->tfm;
372
373 keyidx = data->key_idx;
374 memset(data, 0, sizeof(*data));
375 data->key_idx = keyidx;
376 data->tfm = tfm;
377 if (len == CCMP_TK_LEN) {
378 memcpy(data->key, key, CCMP_TK_LEN);
379 data->key_set = 1;
380 if (seq) {
381 data->rx_pn[0] = seq[5];
382 data->rx_pn[1] = seq[4];
383 data->rx_pn[2] = seq[3];
384 data->rx_pn[3] = seq[2];
385 data->rx_pn[4] = seq[1];
386 data->rx_pn[5] = seq[0];
387 }
388 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
389 } else if (len == 0)
390 data->key_set = 0;
391 else
392 return -1;
393
394 return 0;
395}
396
397
398static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
399{
400 struct ieee80211_ccmp_data *data = priv;
401
402 if (len < CCMP_TK_LEN)
403 return -1;
404
405 if (!data->key_set)
406 return 0;
407 memcpy(key, data->key, CCMP_TK_LEN);
408
409 if (seq) {
410 seq[0] = data->tx_pn[5];
411 seq[1] = data->tx_pn[4];
412 seq[2] = data->tx_pn[3];
413 seq[3] = data->tx_pn[2];
414 seq[4] = data->tx_pn[1];
415 seq[5] = data->tx_pn[0];
416 }
417
418 return CCMP_TK_LEN;
419}
420
421
422static char * ieee80211_ccmp_print_stats(char *p, void *priv)
423{
424 struct ieee80211_ccmp_data *ccmp = priv;
425 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
426 "tx_pn=%02x%02x%02x%02x%02x%02x "
427 "rx_pn=%02x%02x%02x%02x%02x%02x "
428 "format_errors=%d replays=%d decrypt_errors=%d\n",
429 ccmp->key_idx, ccmp->key_set,
430 MAC_ARG(ccmp->tx_pn), MAC_ARG(ccmp->rx_pn),
431 ccmp->dot11RSNAStatsCCMPFormatErrors,
432 ccmp->dot11RSNAStatsCCMPReplays,
433 ccmp->dot11RSNAStatsCCMPDecryptErrors);
434
435 return p;
436}
437
438void ieee80211_ccmp_null(void)
439{
440
441 return;
442}
443static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
444 .name = "CCMP",
445 .init = ieee80211_ccmp_init,
446 .deinit = ieee80211_ccmp_deinit,
447 .encrypt_mpdu = ieee80211_ccmp_encrypt,
448 .decrypt_mpdu = ieee80211_ccmp_decrypt,
449 .encrypt_msdu = NULL,
450 .decrypt_msdu = NULL,
451 .set_key = ieee80211_ccmp_set_key,
452 .get_key = ieee80211_ccmp_get_key,
453 .print_stats = ieee80211_ccmp_print_stats,
454 .extra_prefix_len = CCMP_HDR_LEN,
455 .extra_postfix_len = CCMP_MIC_LEN,
456 .owner = THIS_MODULE,
457};
458
459
460int ieee80211_crypto_ccmp_init(void)
461{
462 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
463}
464
465
466void ieee80211_crypto_ccmp_exit(void)
467{
468 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
469}
470
