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