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13#include <linux/kernel.h>
14#include <linux/err.h>
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 <asm/string.h>
24#include <linux/wireless.h>
25
26#include <linux/ieee80211.h>
27
28#include <linux/crypto.h>
29
30#include <net/lib80211.h>
31
32MODULE_AUTHOR("Jouni Malinen");
33MODULE_DESCRIPTION("Host AP crypt: CCMP");
34MODULE_LICENSE("GPL");
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 lib80211_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_cipher *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
63static inline void lib80211_ccmp_aes_encrypt(struct crypto_cipher *tfm,
64 const u8 pt[16], u8 ct[16])
65{
66 crypto_cipher_encrypt_one(tfm, ct, pt);
67}
68
69static void *lib80211_ccmp_init(int key_idx)
70{
71 struct lib80211_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 = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
79 if (IS_ERR(priv->tfm)) {
80 priv->tfm = NULL;
81 goto fail;
82 }
83
84 return priv;
85
86 fail:
87 if (priv) {
88 if (priv->tfm)
89 crypto_free_cipher(priv->tfm);
90 kfree(priv);
91 }
92
93 return NULL;
94}
95
96static void lib80211_ccmp_deinit(void *priv)
97{
98 struct lib80211_ccmp_data *_priv = priv;
99 if (_priv && _priv->tfm)
100 crypto_free_cipher(_priv->tfm);
101 kfree(priv);
102}
103
104static inline void xor_block(u8 * b, u8 * a, size_t len)
105{
106 int i;
107 for (i = 0; i < len; i++)
108 b[i] ^= a[i];
109}
110
111static void ccmp_init_blocks(struct crypto_cipher *tfm,
112 struct ieee80211_hdr *hdr,
113 u8 * pn, size_t dlen, u8 * b0, u8 * auth, u8 * s0)
114{
115 u8 *pos, qc = 0;
116 size_t aad_len;
117 int a4_included, qc_included;
118 u8 aad[2 * AES_BLOCK_LEN];
119
120 a4_included = ieee80211_has_a4(hdr->frame_control);
121 qc_included = ieee80211_is_data_qos(hdr->frame_control);
122
123 aad_len = 22;
124 if (a4_included)
125 aad_len += 6;
126 if (qc_included) {
127 pos = (u8 *) & hdr->addr4;
128 if (a4_included)
129 pos += 6;
130 qc = *pos & 0x0f;
131 aad_len += 2;
132 }
133
134
135
136
137
138
139 b0[0] = 0x59;
140 b0[1] = qc;
141 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
142 memcpy(b0 + 8, pn, CCMP_PN_LEN);
143 b0[14] = (dlen >> 8) & 0xff;
144 b0[15] = dlen & 0xff;
145
146
147
148
149
150
151
152
153 pos = (u8 *) hdr;
154 aad[0] = 0;
155 aad[1] = aad_len & 0xff;
156 aad[2] = pos[0] & 0x8f;
157 aad[3] = pos[1] & 0xc7;
158 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
159 pos = (u8 *) & hdr->seq_ctrl;
160 aad[22] = pos[0] & 0x0f;
161 aad[23] = 0;
162 memset(aad + 24, 0, 8);
163 if (a4_included)
164 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
165 if (qc_included) {
166 aad[a4_included ? 30 : 24] = qc;
167
168 }
169
170
171 lib80211_ccmp_aes_encrypt(tfm, b0, auth);
172 xor_block(auth, aad, AES_BLOCK_LEN);
173 lib80211_ccmp_aes_encrypt(tfm, auth, auth);
174 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
175 lib80211_ccmp_aes_encrypt(tfm, auth, auth);
176 b0[0] &= 0x07;
177 b0[14] = b0[15] = 0;
178 lib80211_ccmp_aes_encrypt(tfm, b0, s0);
179}
180
181static int lib80211_ccmp_hdr(struct sk_buff *skb, int hdr_len,
182 u8 *aeskey, int keylen, void *priv)
183{
184 struct lib80211_ccmp_data *key = priv;
185 int i;
186 u8 *pos;
187
188 if (skb_headroom(skb) < CCMP_HDR_LEN || skb->len < hdr_len)
189 return -1;
190
191 if (aeskey != NULL && keylen >= CCMP_TK_LEN)
192 memcpy(aeskey, key->key, CCMP_TK_LEN);
193
194 pos = skb_push(skb, CCMP_HDR_LEN);
195 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
196 pos += hdr_len;
197
198 i = CCMP_PN_LEN - 1;
199 while (i >= 0) {
200 key->tx_pn[i]++;
201 if (key->tx_pn[i] != 0)
202 break;
203 i--;
204 }
205
206 *pos++ = key->tx_pn[5];
207 *pos++ = key->tx_pn[4];
208 *pos++ = 0;
209 *pos++ = (key->key_idx << 6) | (1 << 5) ;
210 *pos++ = key->tx_pn[3];
211 *pos++ = key->tx_pn[2];
212 *pos++ = key->tx_pn[1];
213 *pos++ = key->tx_pn[0];
214
215 return CCMP_HDR_LEN;
216}
217
218static int lib80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
219{
220 struct lib80211_ccmp_data *key = priv;
221 int data_len, i, blocks, last, len;
222 u8 *pos, *mic;
223 struct ieee80211_hdr *hdr;
224 u8 *b0 = key->tx_b0;
225 u8 *b = key->tx_b;
226 u8 *e = key->tx_e;
227 u8 *s0 = key->tx_s0;
228
229 if (skb_tailroom(skb) < CCMP_MIC_LEN || skb->len < hdr_len)
230 return -1;
231
232 data_len = skb->len - hdr_len;
233 len = lib80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv);
234 if (len < 0)
235 return -1;
236
237 pos = skb->data + hdr_len + CCMP_HDR_LEN;
238 hdr = (struct ieee80211_hdr *)skb->data;
239 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
240
241 blocks = DIV_ROUND_UP(data_len, 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 lib80211_ccmp_aes_encrypt(key->tfm, b, b);
249
250 b0[14] = (i >> 8) & 0xff;
251 b0[15] = i & 0xff;
252 lib80211_ccmp_aes_encrypt(key->tfm, b0, e);
253 xor_block(pos, e, len);
254 pos += len;
255 }
256
257 mic = skb_put(skb, CCMP_MIC_LEN);
258 for (i = 0; i < CCMP_MIC_LEN; i++)
259 mic[i] = b[i] ^ s0[i];
260
261 return 0;
262}
263
264
265
266
267
268static inline int ccmp_replay_check(u8 *pn_n, u8 *pn_o)
269{
270 u32 iv32_n, iv16_n;
271 u32 iv32_o, iv16_o;
272
273 iv32_n = (pn_n[0] << 24) | (pn_n[1] << 16) | (pn_n[2] << 8) | pn_n[3];
274 iv16_n = (pn_n[4] << 8) | pn_n[5];
275
276 iv32_o = (pn_o[0] << 24) | (pn_o[1] << 16) | (pn_o[2] << 8) | pn_o[3];
277 iv16_o = (pn_o[4] << 8) | pn_o[5];
278
279 if ((s32)iv32_n - (s32)iv32_o < 0 ||
280 (iv32_n == iv32_o && iv16_n <= iv16_o))
281 return 1;
282 return 0;
283}
284
285static int lib80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
286{
287 struct lib80211_ccmp_data *key = priv;
288 u8 keyidx, *pos;
289 struct ieee80211_hdr *hdr;
290 u8 *b0 = key->rx_b0;
291 u8 *b = key->rx_b;
292 u8 *a = key->rx_a;
293 u8 pn[6];
294 int i, blocks, last, len;
295 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
296 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
297
298 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
299 key->dot11RSNAStatsCCMPFormatErrors++;
300 return -1;
301 }
302
303 hdr = (struct ieee80211_hdr *)skb->data;
304 pos = skb->data + hdr_len;
305 keyidx = pos[3];
306 if (!(keyidx & (1 << 5))) {
307 net_dbg_ratelimited("CCMP: received packet without ExtIV flag from %pM\n",
308 hdr->addr2);
309 key->dot11RSNAStatsCCMPFormatErrors++;
310 return -2;
311 }
312 keyidx >>= 6;
313 if (key->key_idx != keyidx) {
314 net_dbg_ratelimited("CCMP: RX tkey->key_idx=%d frame keyidx=%d\n",
315 key->key_idx, keyidx);
316 return -6;
317 }
318 if (!key->key_set) {
319 net_dbg_ratelimited("CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
320 hdr->addr2, keyidx);
321 return -3;
322 }
323
324 pn[0] = pos[7];
325 pn[1] = pos[6];
326 pn[2] = pos[5];
327 pn[3] = pos[4];
328 pn[4] = pos[1];
329 pn[5] = pos[0];
330 pos += 8;
331
332 if (ccmp_replay_check(pn, key->rx_pn)) {
333#ifdef CONFIG_LIB80211_DEBUG
334 net_dbg_ratelimited("CCMP: replay detected: STA=%pM previous PN %02x%02x%02x%02x%02x%02x received PN %02x%02x%02x%02x%02x%02x\n",
335 hdr->addr2,
336 key->rx_pn[0], key->rx_pn[1], key->rx_pn[2],
337 key->rx_pn[3], key->rx_pn[4], key->rx_pn[5],
338 pn[0], pn[1], pn[2], pn[3], pn[4], pn[5]);
339#endif
340 key->dot11RSNAStatsCCMPReplays++;
341 return -4;
342 }
343
344 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
345 xor_block(mic, b, CCMP_MIC_LEN);
346
347 blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
348 last = data_len % AES_BLOCK_LEN;
349
350 for (i = 1; i <= blocks; i++) {
351 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
352
353 b0[14] = (i >> 8) & 0xff;
354 b0[15] = i & 0xff;
355 lib80211_ccmp_aes_encrypt(key->tfm, b0, b);
356 xor_block(pos, b, len);
357
358 xor_block(a, pos, len);
359 lib80211_ccmp_aes_encrypt(key->tfm, a, a);
360 pos += len;
361 }
362
363 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
364 net_dbg_ratelimited("CCMP: decrypt failed: STA=%pM\n",
365 hdr->addr2);
366 key->dot11RSNAStatsCCMPDecryptErrors++;
367 return -5;
368 }
369
370 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
371
372
373 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
374 skb_pull(skb, CCMP_HDR_LEN);
375 skb_trim(skb, skb->len - CCMP_MIC_LEN);
376
377 return keyidx;
378}
379
380static int lib80211_ccmp_set_key(void *key, int len, u8 * seq, void *priv)
381{
382 struct lib80211_ccmp_data *data = priv;
383 int keyidx;
384 struct crypto_cipher *tfm = data->tfm;
385
386 keyidx = data->key_idx;
387 memset(data, 0, sizeof(*data));
388 data->key_idx = keyidx;
389 data->tfm = tfm;
390 if (len == CCMP_TK_LEN) {
391 memcpy(data->key, key, CCMP_TK_LEN);
392 data->key_set = 1;
393 if (seq) {
394 data->rx_pn[0] = seq[5];
395 data->rx_pn[1] = seq[4];
396 data->rx_pn[2] = seq[3];
397 data->rx_pn[3] = seq[2];
398 data->rx_pn[4] = seq[1];
399 data->rx_pn[5] = seq[0];
400 }
401 crypto_cipher_setkey(data->tfm, data->key, CCMP_TK_LEN);
402 } else if (len == 0)
403 data->key_set = 0;
404 else
405 return -1;
406
407 return 0;
408}
409
410static int lib80211_ccmp_get_key(void *key, int len, u8 * seq, void *priv)
411{
412 struct lib80211_ccmp_data *data = priv;
413
414 if (len < CCMP_TK_LEN)
415 return -1;
416
417 if (!data->key_set)
418 return 0;
419 memcpy(key, data->key, CCMP_TK_LEN);
420
421 if (seq) {
422 seq[0] = data->tx_pn[5];
423 seq[1] = data->tx_pn[4];
424 seq[2] = data->tx_pn[3];
425 seq[3] = data->tx_pn[2];
426 seq[4] = data->tx_pn[1];
427 seq[5] = data->tx_pn[0];
428 }
429
430 return CCMP_TK_LEN;
431}
432
433static void lib80211_ccmp_print_stats(struct seq_file *m, void *priv)
434{
435 struct lib80211_ccmp_data *ccmp = priv;
436
437 seq_printf(m,
438 "key[%d] alg=CCMP key_set=%d "
439 "tx_pn=%02x%02x%02x%02x%02x%02x "
440 "rx_pn=%02x%02x%02x%02x%02x%02x "
441 "format_errors=%d replays=%d decrypt_errors=%d\n",
442 ccmp->key_idx, ccmp->key_set,
443 ccmp->tx_pn[0], ccmp->tx_pn[1], ccmp->tx_pn[2],
444 ccmp->tx_pn[3], ccmp->tx_pn[4], ccmp->tx_pn[5],
445 ccmp->rx_pn[0], ccmp->rx_pn[1], ccmp->rx_pn[2],
446 ccmp->rx_pn[3], ccmp->rx_pn[4], ccmp->rx_pn[5],
447 ccmp->dot11RSNAStatsCCMPFormatErrors,
448 ccmp->dot11RSNAStatsCCMPReplays,
449 ccmp->dot11RSNAStatsCCMPDecryptErrors);
450}
451
452static struct lib80211_crypto_ops lib80211_crypt_ccmp = {
453 .name = "CCMP",
454 .init = lib80211_ccmp_init,
455 .deinit = lib80211_ccmp_deinit,
456 .encrypt_mpdu = lib80211_ccmp_encrypt,
457 .decrypt_mpdu = lib80211_ccmp_decrypt,
458 .encrypt_msdu = NULL,
459 .decrypt_msdu = NULL,
460 .set_key = lib80211_ccmp_set_key,
461 .get_key = lib80211_ccmp_get_key,
462 .print_stats = lib80211_ccmp_print_stats,
463 .extra_mpdu_prefix_len = CCMP_HDR_LEN,
464 .extra_mpdu_postfix_len = CCMP_MIC_LEN,
465 .owner = THIS_MODULE,
466};
467
468static int __init lib80211_crypto_ccmp_init(void)
469{
470 return lib80211_register_crypto_ops(&lib80211_crypt_ccmp);
471}
472
473static void __exit lib80211_crypto_ccmp_exit(void)
474{
475 lib80211_unregister_crypto_ops(&lib80211_crypt_ccmp);
476}
477
478module_init(lib80211_crypto_ccmp_init);
479module_exit(lib80211_crypto_ccmp_exit);
480
