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12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/slab.h>
15#include <linux/random.h>
16#include <linux/skbuff.h>
17#include <linux/netdevice.h>
18#include <linux/if_ether.h>
19#include <linux/if_arp.h>
20#include <linux/string.h>
21#include <linux/wireless.h>
22#include "rtllib.h"
23
24#include <linux/crypto.h>
25
26#include <linux/scatterlist.h>
27
28#define AES_BLOCK_LEN 16
29#define CCMP_HDR_LEN 8
30#define CCMP_MIC_LEN 8
31#define CCMP_TK_LEN 16
32#define CCMP_PN_LEN 6
33
34struct rtllib_ccmp_data {
35 u8 key[CCMP_TK_LEN];
36 int key_set;
37
38 u8 tx_pn[CCMP_PN_LEN];
39 u8 rx_pn[CCMP_PN_LEN];
40
41 u32 dot11RSNAStatsCCMPFormatErrors;
42 u32 dot11RSNAStatsCCMPReplays;
43 u32 dot11RSNAStatsCCMPDecryptErrors;
44
45 int key_idx;
46
47 struct crypto_tfm *tfm;
48
49
50 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
51 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
52 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
53};
54
55static void rtllib_ccmp_aes_encrypt(struct crypto_tfm *tfm,
56 const u8 pt[16], u8 ct[16])
57{
58 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
59}
60
61static void *rtllib_ccmp_init(int key_idx)
62{
63 struct rtllib_ccmp_data *priv;
64
65 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
66 if (priv == NULL)
67 goto fail;
68 priv->key_idx = key_idx;
69
70 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
71 if (IS_ERR(priv->tfm)) {
72 pr_debug("rtllib_crypt_ccmp: could not allocate crypto API aes\n");
73 priv->tfm = NULL;
74 goto fail;
75 }
76 return priv;
77
78fail:
79 if (priv) {
80 if (priv->tfm)
81 crypto_free_cipher((void *)priv->tfm);
82 kfree(priv);
83 }
84
85 return NULL;
86}
87
88
89static void rtllib_ccmp_deinit(void *priv)
90{
91 struct rtllib_ccmp_data *_priv = priv;
92
93 if (_priv && _priv->tfm)
94 crypto_free_cipher((void *)_priv->tfm);
95 kfree(priv);
96}
97
98
99static inline void xor_block(u8 *b, u8 *a, size_t len)
100{
101 int i;
102
103 for (i = 0; i < len; i++)
104 b[i] ^= a[i];
105}
106
107
108
109static void ccmp_init_blocks(struct crypto_tfm *tfm,
110 struct rtllib_hdr_4addr *hdr,
111 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
112 u8 *s0)
113{
114 u8 *pos, qc = 0;
115 size_t aad_len;
116 u16 fc;
117 int a4_included, qc_included;
118 u8 aad[2 * AES_BLOCK_LEN];
119
120 fc = le16_to_cpu(hdr->frame_ctl);
121 a4_included = ((fc & (RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS)) ==
122 (RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS));
123
124 qc_included = ((WLAN_FC_GET_TYPE(fc) == RTLLIB_FTYPE_DATA) &&
125 (WLAN_FC_GET_STYPE(fc) & 0x80));
126 aad_len = 22;
127 if (a4_included)
128 aad_len += 6;
129 if (qc_included) {
130 pos = (u8 *) &hdr->addr4;
131 if (a4_included)
132 pos += 6;
133 qc = *pos & 0x0f;
134 aad_len += 2;
135 }
136
137
138
139
140
141
142 b0[0] = 0x59;
143 b0[1] = qc;
144 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
145 memcpy(b0 + 8, pn, CCMP_PN_LEN);
146 b0[14] = (dlen >> 8) & 0xff;
147 b0[15] = dlen & 0xff;
148
149
150
151
152
153
154
155
156 pos = (u8 *) hdr;
157 aad[0] = 0;
158 aad[1] = aad_len & 0xff;
159 aad[2] = pos[0] & 0x8f;
160 aad[3] = pos[1] & 0xc7;
161 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
162 pos = (u8 *) &hdr->seq_ctl;
163 aad[22] = pos[0] & 0x0f;
164 aad[23] = 0;
165 memset(aad + 24, 0, 8);
166 if (a4_included)
167 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
168 if (qc_included) {
169 aad[a4_included ? 30 : 24] = qc;
170
171 }
172
173
174 rtllib_ccmp_aes_encrypt(tfm, b0, auth);
175 xor_block(auth, aad, AES_BLOCK_LEN);
176 rtllib_ccmp_aes_encrypt(tfm, auth, auth);
177 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
178 rtllib_ccmp_aes_encrypt(tfm, auth, auth);
179 b0[0] &= 0x07;
180 b0[14] = b0[15] = 0;
181 rtllib_ccmp_aes_encrypt(tfm, b0, s0);
182}
183
184
185
186static int rtllib_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
187{
188 struct rtllib_ccmp_data *key = priv;
189 int data_len, i;
190 u8 *pos;
191 struct rtllib_hdr_4addr *hdr;
192 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
193 MAX_DEV_ADDR_SIZE);
194 if (skb_headroom(skb) < CCMP_HDR_LEN ||
195 skb_tailroom(skb) < CCMP_MIC_LEN ||
196 skb->len < hdr_len)
197 return -1;
198
199 data_len = skb->len - hdr_len;
200 pos = skb_push(skb, CCMP_HDR_LEN);
201 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
202 pos += hdr_len;
203
204 i = CCMP_PN_LEN - 1;
205 while (i >= 0) {
206 key->tx_pn[i]++;
207 if (key->tx_pn[i] != 0)
208 break;
209 i--;
210 }
211
212 *pos++ = key->tx_pn[5];
213 *pos++ = key->tx_pn[4];
214 *pos++ = 0;
215 *pos++ = (key->key_idx << 6) | (1 << 5) ;
216 *pos++ = key->tx_pn[3];
217 *pos++ = key->tx_pn[2];
218 *pos++ = key->tx_pn[1];
219 *pos++ = key->tx_pn[0];
220
221
222 hdr = (struct rtllib_hdr_4addr *) skb->data;
223 if (!tcb_desc->bHwSec) {
224 int blocks, last, len;
225 u8 *mic;
226 u8 *b0 = key->tx_b0;
227 u8 *b = key->tx_b;
228 u8 *e = key->tx_e;
229 u8 *s0 = key->tx_s0;
230
231 mic = skb_put(skb, CCMP_MIC_LEN);
232
233 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len,
234 b0, b, s0);
235
236 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
237 last = data_len % AES_BLOCK_LEN;
238
239 for (i = 1; i <= blocks; i++) {
240 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
241
242 xor_block(b, pos, len);
243 rtllib_ccmp_aes_encrypt(key->tfm, b, b);
244
245 b0[14] = (i >> 8) & 0xff;
246 b0[15] = i & 0xff;
247 rtllib_ccmp_aes_encrypt(key->tfm, b0, e);
248 xor_block(pos, e, len);
249 pos += len;
250 }
251
252 for (i = 0; i < CCMP_MIC_LEN; i++)
253 mic[i] = b[i] ^ s0[i];
254 }
255 return 0;
256}
257
258
259static int rtllib_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
260{
261 struct rtllib_ccmp_data *key = priv;
262 u8 keyidx, *pos;
263 struct rtllib_hdr_4addr *hdr;
264 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
265 MAX_DEV_ADDR_SIZE);
266 u8 pn[6];
267
268 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
269 key->dot11RSNAStatsCCMPFormatErrors++;
270 return -1;
271 }
272
273 hdr = (struct rtllib_hdr_4addr *) skb->data;
274 pos = skb->data + hdr_len;
275 keyidx = pos[3];
276 if (!(keyidx & (1 << 5))) {
277 if (net_ratelimit()) {
278 pr_debug("CCMP: received packet without ExtIV flag from %pM\n",
279 hdr->addr2);
280 }
281 key->dot11RSNAStatsCCMPFormatErrors++;
282 return -2;
283 }
284 keyidx >>= 6;
285 if (key->key_idx != keyidx) {
286 pr_debug("CCMP: RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
287 key->key_idx, keyidx, priv);
288 return -6;
289 }
290 if (!key->key_set) {
291 if (net_ratelimit()) {
292 pr_debug("CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
293 hdr->addr2, keyidx);
294 }
295 return -3;
296 }
297
298 pn[0] = pos[7];
299 pn[1] = pos[6];
300 pn[2] = pos[5];
301 pn[3] = pos[4];
302 pn[4] = pos[1];
303 pn[5] = pos[0];
304 pos += 8;
305 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
306 key->dot11RSNAStatsCCMPReplays++;
307 return -4;
308 }
309 if (!tcb_desc->bHwSec) {
310 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN -
311 CCMP_MIC_LEN;
312 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
313 u8 *b0 = key->rx_b0;
314 u8 *b = key->rx_b;
315 u8 *a = key->rx_a;
316 int i, blocks, last, len;
317
318
319 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
320 xor_block(mic, b, CCMP_MIC_LEN);
321
322 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
323 last = data_len % AES_BLOCK_LEN;
324
325 for (i = 1; i <= blocks; i++) {
326 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
327
328 b0[14] = (i >> 8) & 0xff;
329 b0[15] = i & 0xff;
330 rtllib_ccmp_aes_encrypt(key->tfm, b0, b);
331 xor_block(pos, b, len);
332
333 xor_block(a, pos, len);
334 rtllib_ccmp_aes_encrypt(key->tfm, a, a);
335 pos += len;
336 }
337
338 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
339 if (net_ratelimit()) {
340 pr_debug("CCMP: decrypt failed: STA= %pM\n",
341 hdr->addr2);
342 }
343 key->dot11RSNAStatsCCMPDecryptErrors++;
344 return -5;
345 }
346
347 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
348 }
349
350 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
351 skb_pull(skb, CCMP_HDR_LEN);
352 skb_trim(skb, skb->len - CCMP_MIC_LEN);
353
354 return keyidx;
355}
356
357
358static int rtllib_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
359{
360 struct rtllib_ccmp_data *data = priv;
361 int keyidx;
362 struct crypto_tfm *tfm = data->tfm;
363
364 keyidx = data->key_idx;
365 memset(data, 0, sizeof(*data));
366 data->key_idx = keyidx;
367 data->tfm = tfm;
368 if (len == CCMP_TK_LEN) {
369 memcpy(data->key, key, CCMP_TK_LEN);
370 data->key_set = 1;
371 if (seq) {
372 data->rx_pn[0] = seq[5];
373 data->rx_pn[1] = seq[4];
374 data->rx_pn[2] = seq[3];
375 data->rx_pn[3] = seq[2];
376 data->rx_pn[4] = seq[1];
377 data->rx_pn[5] = seq[0];
378 }
379 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
380 } else if (len == 0)
381 data->key_set = 0;
382 else
383 return -1;
384
385 return 0;
386}
387
388
389static int rtllib_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
390{
391 struct rtllib_ccmp_data *data = priv;
392
393 if (len < CCMP_TK_LEN)
394 return -1;
395
396 if (!data->key_set)
397 return 0;
398 memcpy(key, data->key, CCMP_TK_LEN);
399
400 if (seq) {
401 seq[0] = data->tx_pn[5];
402 seq[1] = data->tx_pn[4];
403 seq[2] = data->tx_pn[3];
404 seq[3] = data->tx_pn[2];
405 seq[4] = data->tx_pn[1];
406 seq[5] = data->tx_pn[0];
407 }
408
409 return CCMP_TK_LEN;
410}
411
412
413static void rtllib_ccmp_print_stats(struct seq_file *m, void *priv)
414{
415 struct rtllib_ccmp_data *ccmp = priv;
416
417 seq_printf(m,
418 "key[%d] alg=CCMP key_set=%d tx_pn=%pM rx_pn=%pM format_errors=%d replays=%d decrypt_errors=%d\n",
419 ccmp->key_idx, ccmp->key_set,
420 ccmp->tx_pn, ccmp->rx_pn,
421 ccmp->dot11RSNAStatsCCMPFormatErrors,
422 ccmp->dot11RSNAStatsCCMPReplays,
423 ccmp->dot11RSNAStatsCCMPDecryptErrors);
424}
425
426static struct lib80211_crypto_ops rtllib_crypt_ccmp = {
427 .name = "R-CCMP",
428 .init = rtllib_ccmp_init,
429 .deinit = rtllib_ccmp_deinit,
430 .encrypt_mpdu = rtllib_ccmp_encrypt,
431 .decrypt_mpdu = rtllib_ccmp_decrypt,
432 .encrypt_msdu = NULL,
433 .decrypt_msdu = NULL,
434 .set_key = rtllib_ccmp_set_key,
435 .get_key = rtllib_ccmp_get_key,
436 .print_stats = rtllib_ccmp_print_stats,
437 .extra_mpdu_prefix_len = CCMP_HDR_LEN,
438 .extra_mpdu_postfix_len = CCMP_MIC_LEN,
439 .owner = THIS_MODULE,
440};
441
442
443static int __init rtllib_crypto_ccmp_init(void)
444{
445 return lib80211_register_crypto_ops(&rtllib_crypt_ccmp);
446}
447
448
449static void __exit rtllib_crypto_ccmp_exit(void)
450{
451 lib80211_unregister_crypto_ops(&rtllib_crypt_ccmp);
452}
453
454module_init(rtllib_crypto_ccmp_init);
455module_exit(rtllib_crypto_ccmp_exit);
456
457MODULE_LICENSE("GPL");
458
