diff options
author | Jeff Garzik <jgarzik@pobox.com> | 2005-05-12 22:48:20 -0400 |
---|---|---|
committer | Jeff Garzik <jgarzik@pobox.com> | 2005-05-12 22:48:20 -0400 |
commit | b453872c35cfcbdbf5a794737817f7d4e7b1b579 (patch) | |
tree | 6639da0b12e3f071b57f388c97d28e451f8f3cd3 /net/ieee80211/ieee80211_crypt_ccmp.c | |
parent | fff9cfd99c0f88645c3f50d7476d6c8cef99f140 (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.c | 470 |
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 | |||
31 | MODULE_AUTHOR("Jouni Malinen"); | ||
32 | MODULE_DESCRIPTION("Host AP crypt: CCMP"); | ||
33 | MODULE_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 | |||
41 | struct 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 | |||
62 | void 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 | |||
78 | static 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 | |||
97 | fail: | ||
98 | if (priv) { | ||
99 | if (priv->tfm) | ||
100 | crypto_free_tfm(priv->tfm); | ||
101 | kfree(priv); | ||
102 | } | ||
103 | |||
104 | return NULL; | ||
105 | } | ||
106 | |||
107 | |||
108 | static 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 | |||
117 | static 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 | |||
125 | static 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 | |||
200 | static 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 | |||
265 | static 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 | |||
368 | static 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 | |||
399 | static 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 | |||
423 | static 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 | |||
440 | static 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 | |||
457 | static int __init ieee80211_crypto_ccmp_init(void) | ||
458 | { | ||
459 | return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp); | ||
460 | } | ||
461 | |||
462 | |||
463 | static void __exit ieee80211_crypto_ccmp_exit(void) | ||
464 | { | ||
465 | ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp); | ||
466 | } | ||
467 | |||
468 | |||
469 | module_init(ieee80211_crypto_ccmp_init); | ||
470 | module_exit(ieee80211_crypto_ccmp_exit); | ||