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11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <linux/random.h>
19#include <linux/skbuff.h>
20#include <linux/netdevice.h>
21#include <linux/if_ether.h>
22#include <linux/if_arp.h>
23#include <linux/string.h>
24#include <linux/wireless.h>
25
26#include "ieee80211.h"
27
28#include <linux/crypto.h>
29#include <linux/scatterlist.h>
30
31MODULE_AUTHOR("Jouni Malinen");
32MODULE_DESCRIPTION("Host AP crypt: CCMP");
33MODULE_LICENSE("GPL");
34
35
36#define AES_BLOCK_LEN 16
37#define CCMP_HDR_LEN 8
38#define CCMP_MIC_LEN 8
39#define CCMP_TK_LEN 16
40#define CCMP_PN_LEN 6
41
42struct ieee80211_ccmp_data {
43 u8 key[CCMP_TK_LEN];
44 int key_set;
45
46 u8 tx_pn[CCMP_PN_LEN];
47 u8 rx_pn[CCMP_PN_LEN];
48
49 u32 dot11RSNAStatsCCMPFormatErrors;
50 u32 dot11RSNAStatsCCMPReplays;
51 u32 dot11RSNAStatsCCMPDecryptErrors;
52
53 int key_idx;
54
55 struct crypto_tfm *tfm;
56
57
58 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
59 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
60 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
61};
62
63void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
64 const u8 pt[16], u8 ct[16])
65{
66 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
67}
68
69static void *ieee80211_ccmp_init(int key_idx)
70{
71 struct ieee80211_ccmp_data *priv;
72
73 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
74 if (priv == NULL)
75 goto fail;
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 pr_debug("could not allocate 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 pr_debug("received packet without ExtIV flag from %pM\n",
287 hdr->addr2);
288 }
289 key->dot11RSNAStatsCCMPFormatErrors++;
290 return -2;
291 }
292 keyidx >>= 6;
293 if (key->key_idx != keyidx) {
294 pr_debug("RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
295 key->key_idx, keyidx, priv);
296 return -6;
297 }
298 if (!key->key_set) {
299 if (net_ratelimit()) {
300 pr_debug("received packet from %pM with keyid=%d that does not have a configured key\n",
301 hdr->addr2, keyidx);
302 }
303 return -3;
304 }
305
306 pn[0] = pos[7];
307 pn[1] = pos[6];
308 pn[2] = pos[5];
309 pn[3] = pos[4];
310 pn[4] = pos[1];
311 pn[5] = pos[0];
312 pos += 8;
313
314 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
315 if (net_ratelimit()) {
316 pr_debug("replay detected: STA=%pM previous PN %pm received PN %pm\n",
317 hdr->addr2, key->rx_pn, pn);
318 }
319 key->dot11RSNAStatsCCMPReplays++;
320 return -4;
321 }
322
323 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
324 xor_block(mic, b, CCMP_MIC_LEN);
325
326 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
327 last = data_len % AES_BLOCK_LEN;
328
329 for (i = 1; i <= blocks; i++) {
330 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
331
332 b0[14] = (i >> 8) & 0xff;
333 b0[15] = i & 0xff;
334 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
335 xor_block(pos, b, len);
336
337 xor_block(a, pos, len);
338 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
339 pos += len;
340 }
341
342 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
343 if (net_ratelimit())
344 pr_debug("decrypt failed: STA=%pM\n", hdr->addr2);
345
346 key->dot11RSNAStatsCCMPDecryptErrors++;
347 return -5;
348 }
349
350 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
351
352
353 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
354 skb_pull(skb, CCMP_HDR_LEN);
355 skb_trim(skb, skb->len - CCMP_MIC_LEN);
356
357 return keyidx;
358}
359
360
361static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
362{
363 struct ieee80211_ccmp_data *data = priv;
364 int keyidx;
365 struct crypto_tfm *tfm = data->tfm;
366
367 keyidx = data->key_idx;
368 memset(data, 0, sizeof(*data));
369 data->key_idx = keyidx;
370 data->tfm = tfm;
371 if (len == CCMP_TK_LEN) {
372 memcpy(data->key, key, CCMP_TK_LEN);
373 data->key_set = 1;
374 if (seq) {
375 data->rx_pn[0] = seq[5];
376 data->rx_pn[1] = seq[4];
377 data->rx_pn[2] = seq[3];
378 data->rx_pn[3] = seq[2];
379 data->rx_pn[4] = seq[1];
380 data->rx_pn[5] = seq[0];
381 }
382 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
383 } else if (len == 0)
384 data->key_set = 0;
385 else
386 return -1;
387
388 return 0;
389}
390
391
392static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
393{
394 struct ieee80211_ccmp_data *data = priv;
395
396 if (len < CCMP_TK_LEN)
397 return -1;
398
399 if (!data->key_set)
400 return 0;
401 memcpy(key, data->key, CCMP_TK_LEN);
402
403 if (seq) {
404 seq[0] = data->tx_pn[5];
405 seq[1] = data->tx_pn[4];
406 seq[2] = data->tx_pn[3];
407 seq[3] = data->tx_pn[2];
408 seq[4] = data->tx_pn[1];
409 seq[5] = data->tx_pn[0];
410 }
411
412 return CCMP_TK_LEN;
413}
414
415
416static char *ieee80211_ccmp_print_stats(char *p, void *priv)
417{
418 struct ieee80211_ccmp_data *ccmp = priv;
419 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
420 "tx_pn=%pm rx_pn=%pm "
421 "format_errors=%d replays=%d decrypt_errors=%d\n",
422 ccmp->key_idx, ccmp->key_set,
423 ccmp->tx_pn, ccmp->rx_pn,
424 ccmp->dot11RSNAStatsCCMPFormatErrors,
425 ccmp->dot11RSNAStatsCCMPReplays,
426 ccmp->dot11RSNAStatsCCMPDecryptErrors);
427
428 return p;
429}
430
431void ieee80211_ccmp_null(void)
432{
433
434 return;
435}
436static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
437 .name = "CCMP",
438 .init = ieee80211_ccmp_init,
439 .deinit = ieee80211_ccmp_deinit,
440 .encrypt_mpdu = ieee80211_ccmp_encrypt,
441 .decrypt_mpdu = ieee80211_ccmp_decrypt,
442 .encrypt_msdu = NULL,
443 .decrypt_msdu = NULL,
444 .set_key = ieee80211_ccmp_set_key,
445 .get_key = ieee80211_ccmp_get_key,
446 .print_stats = ieee80211_ccmp_print_stats,
447 .extra_prefix_len = CCMP_HDR_LEN,
448 .extra_postfix_len = CCMP_MIC_LEN,
449 .owner = THIS_MODULE,
450};
451
452
453int ieee80211_crypto_ccmp_init(void)
454{
455 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
456}
457
458
459void ieee80211_crypto_ccmp_exit(void)
460{
461 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
462}
463
