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authorJeff Garzik <jgarzik@pobox.com>2005-05-12 22:48:20 -0400
committerJeff Garzik <jgarzik@pobox.com>2005-05-12 22:48:20 -0400
commitb453872c35cfcbdbf5a794737817f7d4e7b1b579 (patch)
tree6639da0b12e3f071b57f388c97d28e451f8f3cd3 /net/ieee80211/ieee80211_crypt_ccmp.c
parentfff9cfd99c0f88645c3f50d7476d6c8cef99f140 (diff)
[NET] ieee80211 subsystem
Contributors: Host AP contributors James Ketrenos <jketreno@linux.intel.com> Francois Romieu <romieu@fr.zoreil.com> Adrian Bunk <bunk@stusta.de> Matthew Galgoci <mgalgoci@parcelfarce.linux.th eplanet.co.uk>
Diffstat (limited to 'net/ieee80211/ieee80211_crypt_ccmp.c')
-rw-r--r--net/ieee80211/ieee80211_crypt_ccmp.c470
1 files changed, 470 insertions, 0 deletions
diff --git a/net/ieee80211/ieee80211_crypt_ccmp.c b/net/ieee80211/ieee80211_crypt_ccmp.c
new file mode 100644
index 000000000000..f5f412ae7f28
--- /dev/null
+++ b/net/ieee80211/ieee80211_crypt_ccmp.c
@@ -0,0 +1,470 @@
1/*
2 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
3 *
4 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation. See README and COPYING for
9 * more details.
10 */
11
12#include <linux/config.h>
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 <net/ieee80211.h>
26
27
28#include <linux/crypto.h>
29#include <asm/scatterlist.h>
30
31MODULE_AUTHOR("Jouni Malinen");
32MODULE_DESCRIPTION("Host AP crypt: CCMP");
33MODULE_LICENSE("GPL");
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 /* scratch buffers for virt_to_page() (crypto API) */
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 struct scatterlist src, dst;
66
67 src.page = virt_to_page(pt);
68 src.offset = offset_in_page(pt);
69 src.length = AES_BLOCK_LEN;
70
71 dst.page = virt_to_page(ct);
72 dst.offset = offset_in_page(ct);
73 dst.length = AES_BLOCK_LEN;
74
75 crypto_cipher_encrypt(tfm, &dst, &src, AES_BLOCK_LEN);
76}
77
78static void * ieee80211_ccmp_init(int key_idx)
79{
80 struct ieee80211_ccmp_data *priv;
81
82 priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
83 if (priv == NULL)
84 goto fail;
85 memset(priv, 0, sizeof(*priv));
86 priv->key_idx = key_idx;
87
88 priv->tfm = crypto_alloc_tfm("aes", 0);
89 if (priv->tfm == NULL) {
90 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
91 "crypto API aes\n");
92 goto fail;
93 }
94
95 return priv;
96
97fail:
98 if (priv) {
99 if (priv->tfm)
100 crypto_free_tfm(priv->tfm);
101 kfree(priv);
102 }
103
104 return NULL;
105}
106
107
108static void ieee80211_ccmp_deinit(void *priv)
109{
110 struct ieee80211_ccmp_data *_priv = priv;
111 if (_priv && _priv->tfm)
112 crypto_free_tfm(_priv->tfm);
113 kfree(priv);
114}
115
116
117static inline void xor_block(u8 *b, u8 *a, size_t len)
118{
119 int i;
120 for (i = 0; i < len; i++)
121 b[i] ^= a[i];
122}
123
124
125static void ccmp_init_blocks(struct crypto_tfm *tfm,
126 struct ieee80211_hdr *hdr,
127 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
128 u8 *s0)
129{
130 u8 *pos, qc = 0;
131 size_t aad_len;
132 u16 fc;
133 int a4_included, qc_included;
134 u8 aad[2 * AES_BLOCK_LEN];
135
136 fc = le16_to_cpu(hdr->frame_ctl);
137 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
138 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
139 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
140 (WLAN_FC_GET_STYPE(fc) & 0x08));
141 aad_len = 22;
142 if (a4_included)
143 aad_len += 6;
144 if (qc_included) {
145 pos = (u8 *) &hdr->addr4;
146 if (a4_included)
147 pos += 6;
148 qc = *pos & 0x0f;
149 aad_len += 2;
150 }
151
152 /* CCM Initial Block:
153 * Flag (Include authentication header, M=3 (8-octet MIC),
154 * L=1 (2-octet Dlen))
155 * Nonce: 0x00 | A2 | PN
156 * Dlen */
157 b0[0] = 0x59;
158 b0[1] = qc;
159 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
160 memcpy(b0 + 8, pn, CCMP_PN_LEN);
161 b0[14] = (dlen >> 8) & 0xff;
162 b0[15] = dlen & 0xff;
163
164 /* AAD:
165 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
166 * A1 | A2 | A3
167 * SC with bits 4..15 (seq#) masked to zero
168 * A4 (if present)
169 * QC (if present)
170 */
171 pos = (u8 *) hdr;
172 aad[0] = 0; /* aad_len >> 8 */
173 aad[1] = aad_len & 0xff;
174 aad[2] = pos[0] & 0x8f;
175 aad[3] = pos[1] & 0xc7;
176 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
177 pos = (u8 *) &hdr->seq_ctl;
178 aad[22] = pos[0] & 0x0f;
179 aad[23] = 0; /* all bits masked */
180 memset(aad + 24, 0, 8);
181 if (a4_included)
182 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
183 if (qc_included) {
184 aad[a4_included ? 30 : 24] = qc;
185 /* rest of QC masked */
186 }
187
188 /* Start with the first block and AAD */
189 ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
190 xor_block(auth, aad, AES_BLOCK_LEN);
191 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
192 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
193 ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
194 b0[0] &= 0x07;
195 b0[14] = b0[15] = 0;
196 ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
197}
198
199
200static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
201{
202 struct ieee80211_ccmp_data *key = priv;
203 int data_len, i, blocks, last, len;
204 u8 *pos, *mic;
205 struct ieee80211_hdr *hdr;
206 u8 *b0 = key->tx_b0;
207 u8 *b = key->tx_b;
208 u8 *e = key->tx_e;
209 u8 *s0 = key->tx_s0;
210
211 if (skb_headroom(skb) < CCMP_HDR_LEN ||
212 skb_tailroom(skb) < CCMP_MIC_LEN ||
213 skb->len < hdr_len)
214 return -1;
215
216 data_len = skb->len - hdr_len;
217 pos = skb_push(skb, CCMP_HDR_LEN);
218 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
219 pos += hdr_len;
220 mic = skb_put(skb, CCMP_MIC_LEN);
221
222 i = CCMP_PN_LEN - 1;
223 while (i >= 0) {
224 key->tx_pn[i]++;
225 if (key->tx_pn[i] != 0)
226 break;
227 i--;
228 }
229
230 *pos++ = key->tx_pn[5];
231 *pos++ = key->tx_pn[4];
232 *pos++ = 0;
233 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
234 *pos++ = key->tx_pn[3];
235 *pos++ = key->tx_pn[2];
236 *pos++ = key->tx_pn[1];
237 *pos++ = key->tx_pn[0];
238
239 hdr = (struct ieee80211_hdr *) skb->data;
240 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
241
242 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
243 last = data_len % AES_BLOCK_LEN;
244
245 for (i = 1; i <= blocks; i++) {
246 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
247 /* Authentication */
248 xor_block(b, pos, len);
249 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
250 /* Encryption, with counter */
251 b0[14] = (i >> 8) & 0xff;
252 b0[15] = i & 0xff;
253 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
254 xor_block(pos, e, len);
255 pos += len;
256 }
257
258 for (i = 0; i < CCMP_MIC_LEN; i++)
259 mic[i] = b[i] ^ s0[i];
260
261 return 0;
262}
263
264
265static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
266{
267 struct ieee80211_ccmp_data *key = priv;
268 u8 keyidx, *pos;
269 struct ieee80211_hdr *hdr;
270 u8 *b0 = key->rx_b0;
271 u8 *b = key->rx_b;
272 u8 *a = key->rx_a;
273 u8 pn[6];
274 int i, blocks, last, len;
275 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
276 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
277
278 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
279 key->dot11RSNAStatsCCMPFormatErrors++;
280 return -1;
281 }
282
283 hdr = (struct ieee80211_hdr *) skb->data;
284 pos = skb->data + hdr_len;
285 keyidx = pos[3];
286 if (!(keyidx & (1 << 5))) {
287 if (net_ratelimit()) {
288 printk(KERN_DEBUG "CCMP: received packet without ExtIV"
289 " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
290 }
291 key->dot11RSNAStatsCCMPFormatErrors++;
292 return -2;
293 }
294 keyidx >>= 6;
295 if (key->key_idx != keyidx) {
296 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
297 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
298 return -6;
299 }
300 if (!key->key_set) {
301 if (net_ratelimit()) {
302 printk(KERN_DEBUG "CCMP: received packet from " MAC_FMT
303 " with keyid=%d that does not have a configured"
304 " key\n", MAC_ARG(hdr->addr2), keyidx);
305 }
306 return -3;
307 }
308
309 pn[0] = pos[7];
310 pn[1] = pos[6];
311 pn[2] = pos[5];
312 pn[3] = pos[4];
313 pn[4] = pos[1];
314 pn[5] = pos[0];
315 pos += 8;
316
317 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
318 if (net_ratelimit()) {
319 printk(KERN_DEBUG "CCMP: replay detected: STA=" MAC_FMT
320 " previous PN %02x%02x%02x%02x%02x%02x "
321 "received PN %02x%02x%02x%02x%02x%02x\n",
322 MAC_ARG(hdr->addr2), MAC_ARG(key->rx_pn),
323 MAC_ARG(pn));
324 }
325 key->dot11RSNAStatsCCMPReplays++;
326 return -4;
327 }
328
329 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
330 xor_block(mic, b, CCMP_MIC_LEN);
331
332 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
333 last = data_len % AES_BLOCK_LEN;
334
335 for (i = 1; i <= blocks; i++) {
336 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
337 /* Decrypt, with counter */
338 b0[14] = (i >> 8) & 0xff;
339 b0[15] = i & 0xff;
340 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
341 xor_block(pos, b, len);
342 /* Authentication */
343 xor_block(a, pos, len);
344 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
345 pos += len;
346 }
347
348 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
349 if (net_ratelimit()) {
350 printk(KERN_DEBUG "CCMP: decrypt failed: STA="
351 MAC_FMT "\n", MAC_ARG(hdr->addr2));
352 }
353 key->dot11RSNAStatsCCMPDecryptErrors++;
354 return -5;
355 }
356
357 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
358
359 /* Remove hdr and MIC */
360 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
361 skb_pull(skb, CCMP_HDR_LEN);
362 skb_trim(skb, skb->len - CCMP_MIC_LEN);
363
364 return keyidx;
365}
366
367
368static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
369{
370 struct ieee80211_ccmp_data *data = priv;
371 int keyidx;
372 struct crypto_tfm *tfm = data->tfm;
373
374 keyidx = data->key_idx;
375 memset(data, 0, sizeof(*data));
376 data->key_idx = keyidx;
377 data->tfm = tfm;
378 if (len == CCMP_TK_LEN) {
379 memcpy(data->key, key, CCMP_TK_LEN);
380 data->key_set = 1;
381 if (seq) {
382 data->rx_pn[0] = seq[5];
383 data->rx_pn[1] = seq[4];
384 data->rx_pn[2] = seq[3];
385 data->rx_pn[3] = seq[2];
386 data->rx_pn[4] = seq[1];
387 data->rx_pn[5] = seq[0];
388 }
389 crypto_cipher_setkey(data->tfm, data->key, CCMP_TK_LEN);
390 } else if (len == 0)
391 data->key_set = 0;
392 else
393 return -1;
394
395 return 0;
396}
397
398
399static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
400{
401 struct ieee80211_ccmp_data *data = priv;
402
403 if (len < CCMP_TK_LEN)
404 return -1;
405
406 if (!data->key_set)
407 return 0;
408 memcpy(key, data->key, CCMP_TK_LEN);
409
410 if (seq) {
411 seq[0] = data->tx_pn[5];
412 seq[1] = data->tx_pn[4];
413 seq[2] = data->tx_pn[3];
414 seq[3] = data->tx_pn[2];
415 seq[4] = data->tx_pn[1];
416 seq[5] = data->tx_pn[0];
417 }
418
419 return CCMP_TK_LEN;
420}
421
422
423static char * ieee80211_ccmp_print_stats(char *p, void *priv)
424{
425 struct ieee80211_ccmp_data *ccmp = priv;
426 p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
427 "tx_pn=%02x%02x%02x%02x%02x%02x "
428 "rx_pn=%02x%02x%02x%02x%02x%02x "
429 "format_errors=%d replays=%d decrypt_errors=%d\n",
430 ccmp->key_idx, ccmp->key_set,
431 MAC_ARG(ccmp->tx_pn), MAC_ARG(ccmp->rx_pn),
432 ccmp->dot11RSNAStatsCCMPFormatErrors,
433 ccmp->dot11RSNAStatsCCMPReplays,
434 ccmp->dot11RSNAStatsCCMPDecryptErrors);
435
436 return p;
437}
438
439
440static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
441 .name = "CCMP",
442 .init = ieee80211_ccmp_init,
443 .deinit = ieee80211_ccmp_deinit,
444 .encrypt_mpdu = ieee80211_ccmp_encrypt,
445 .decrypt_mpdu = ieee80211_ccmp_decrypt,
446 .encrypt_msdu = NULL,
447 .decrypt_msdu = NULL,
448 .set_key = ieee80211_ccmp_set_key,
449 .get_key = ieee80211_ccmp_get_key,
450 .print_stats = ieee80211_ccmp_print_stats,
451 .extra_prefix_len = CCMP_HDR_LEN,
452 .extra_postfix_len = CCMP_MIC_LEN,
453 .owner = THIS_MODULE,
454};
455
456
457static int __init ieee80211_crypto_ccmp_init(void)
458{
459 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
460}
461
462
463static void __exit ieee80211_crypto_ccmp_exit(void)
464{
465 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
466}
467
468
469module_init(ieee80211_crypto_ccmp_init);
470module_exit(ieee80211_crypto_ccmp_exit);