2 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
4 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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
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>
25 #include "ieee80211.h"
27 #include <linux/crypto.h>
28 #include <linux/scatterlist.h>
30 MODULE_AUTHOR("Jouni Malinen");
31 MODULE_DESCRIPTION("Host AP crypt: CCMP");
32 MODULE_LICENSE("GPL");
34 #define AES_BLOCK_LEN 16
35 #define CCMP_HDR_LEN 8
36 #define CCMP_MIC_LEN 8
37 #define CCMP_TK_LEN 16
40 struct ieee80211_ccmp_data
{
44 u8 tx_pn
[CCMP_PN_LEN
];
45 u8 rx_pn
[CCMP_PN_LEN
];
47 u32 dot11RSNAStatsCCMPFormatErrors
;
48 u32 dot11RSNAStatsCCMPReplays
;
49 u32 dot11RSNAStatsCCMPDecryptErrors
;
53 struct crypto_tfm
*tfm
;
55 /* scratch buffers for virt_to_page() (crypto API) */
56 u8 tx_b0
[AES_BLOCK_LEN
], tx_b
[AES_BLOCK_LEN
],
57 tx_e
[AES_BLOCK_LEN
], tx_s0
[AES_BLOCK_LEN
];
58 u8 rx_b0
[AES_BLOCK_LEN
], rx_b
[AES_BLOCK_LEN
], rx_a
[AES_BLOCK_LEN
];
61 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm
*tfm
,
62 const u8 pt
[16], u8 ct
[16])
64 crypto_cipher_encrypt_one((void*)tfm
, ct
, pt
);
67 static void * ieee80211_ccmp_init(int key_idx
)
69 struct ieee80211_ccmp_data
*priv
;
71 priv
= kzalloc(sizeof(*priv
), GFP_ATOMIC
);
74 priv
->key_idx
= key_idx
;
76 priv
->tfm
= (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC
);
77 if (IS_ERR(priv
->tfm
)) {
78 printk(KERN_DEBUG
"ieee80211_crypt_ccmp: could not allocate "
89 crypto_free_cipher((void*)priv
->tfm
);
97 static void ieee80211_ccmp_deinit(void *priv
)
99 struct ieee80211_ccmp_data
*_priv
= priv
;
101 if (_priv
&& _priv
->tfm
)
102 crypto_free_cipher((void*)_priv
->tfm
);
107 static inline void xor_block(u8
*b
, u8
*a
, size_t len
)
110 for (i
= 0; i
< len
; i
++)
116 static void ccmp_init_blocks(struct crypto_tfm
*tfm
,
117 struct ieee80211_hdr_4addr
*hdr
,
118 u8
*pn
, size_t dlen
, u8
*b0
, u8
*auth
,
124 int a4_included
, qc_included
;
125 u8 aad
[2 * AES_BLOCK_LEN
];
127 fc
= le16_to_cpu(hdr
->frame_ctl
);
128 a4_included
= ((fc
& (IEEE80211_FCTL_TODS
| IEEE80211_FCTL_FROMDS
)) ==
129 (IEEE80211_FCTL_TODS
| IEEE80211_FCTL_FROMDS
));
131 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
132 (WLAN_FC_GET_STYPE(fc) & 0x08));
134 // fixed by David :2006.9.6
135 qc_included
= ((WLAN_FC_GET_TYPE(fc
) == IEEE80211_FTYPE_DATA
) &&
136 (WLAN_FC_GET_STYPE(fc
) & 0x80));
141 pos
= (u8
*) &hdr
->addr4
;
147 /* CCM Initial Block:
148 * Flag (Include authentication header, M=3 (8-octet MIC),
149 * L=1 (2-octet Dlen))
150 * Nonce: 0x00 | A2 | PN
154 memcpy(b0
+ 2, hdr
->addr2
, ETH_ALEN
);
155 memcpy(b0
+ 8, pn
, CCMP_PN_LEN
);
156 b0
[14] = (dlen
>> 8) & 0xff;
157 b0
[15] = dlen
& 0xff;
160 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
162 * SC with bits 4..15 (seq#) masked to zero
167 aad
[0] = 0; /* aad_len >> 8 */
168 aad
[1] = aad_len
& 0xff;
169 aad
[2] = pos
[0] & 0x8f;
170 aad
[3] = pos
[1] & 0xc7;
171 memcpy(aad
+ 4, hdr
->addr1
, 3 * ETH_ALEN
);
172 pos
= (u8
*) &hdr
->seq_ctl
;
173 aad
[22] = pos
[0] & 0x0f;
174 aad
[23] = 0; /* all bits masked */
175 memset(aad
+ 24, 0, 8);
177 memcpy(aad
+ 24, hdr
->addr4
, ETH_ALEN
);
179 aad
[a4_included
? 30 : 24] = qc
;
180 /* rest of QC masked */
183 /* Start with the first block and AAD */
184 ieee80211_ccmp_aes_encrypt(tfm
, b0
, auth
);
185 xor_block(auth
, aad
, AES_BLOCK_LEN
);
186 ieee80211_ccmp_aes_encrypt(tfm
, auth
, auth
);
187 xor_block(auth
, &aad
[AES_BLOCK_LEN
], AES_BLOCK_LEN
);
188 ieee80211_ccmp_aes_encrypt(tfm
, auth
, auth
);
191 ieee80211_ccmp_aes_encrypt(tfm
, b0
, s0
);
196 static int ieee80211_ccmp_encrypt(struct sk_buff
*skb
, int hdr_len
, void *priv
)
198 struct ieee80211_ccmp_data
*key
= priv
;
201 struct ieee80211_hdr_4addr
*hdr
;
202 cb_desc
*tcb_desc
= (cb_desc
*)(skb
->cb
+ MAX_DEV_ADDR_SIZE
);
204 if (skb_headroom(skb
) < CCMP_HDR_LEN
||
205 skb_tailroom(skb
) < CCMP_MIC_LEN
||
209 data_len
= skb
->len
- hdr_len
;
210 pos
= skb_push(skb
, CCMP_HDR_LEN
);
211 memmove(pos
, pos
+ CCMP_HDR_LEN
, hdr_len
);
213 // mic = skb_put(skb, CCMP_MIC_LEN);
218 if (key
->tx_pn
[i
] != 0)
223 *pos
++ = key
->tx_pn
[5];
224 *pos
++ = key
->tx_pn
[4];
226 *pos
++ = (key
->key_idx
<< 6) | (1 << 5) /* Ext IV included */;
227 *pos
++ = key
->tx_pn
[3];
228 *pos
++ = key
->tx_pn
[2];
229 *pos
++ = key
->tx_pn
[1];
230 *pos
++ = key
->tx_pn
[0];
233 hdr
= (struct ieee80211_hdr_4addr
*) skb
->data
;
234 if (!tcb_desc
->bHwSec
)
236 int blocks
, last
, len
;
243 //mic is moved to here by john
244 mic
= skb_put(skb
, CCMP_MIC_LEN
);
246 ccmp_init_blocks(key
->tfm
, hdr
, key
->tx_pn
, data_len
, b0
, b
, s0
);
248 blocks
= (data_len
+ AES_BLOCK_LEN
- 1) / AES_BLOCK_LEN
;
249 last
= data_len
% AES_BLOCK_LEN
;
251 for (i
= 1; i
<= blocks
; i
++) {
252 len
= (i
== blocks
&& last
) ? last
: AES_BLOCK_LEN
;
254 xor_block(b
, pos
, len
);
255 ieee80211_ccmp_aes_encrypt(key
->tfm
, b
, b
);
256 /* Encryption, with counter */
257 b0
[14] = (i
>> 8) & 0xff;
259 ieee80211_ccmp_aes_encrypt(key
->tfm
, b0
, e
);
260 xor_block(pos
, e
, len
);
264 for (i
= 0; i
< CCMP_MIC_LEN
; i
++)
265 mic
[i
] = b
[i
] ^ s0
[i
];
271 static int ieee80211_ccmp_decrypt(struct sk_buff
*skb
, int hdr_len
, void *priv
)
273 struct ieee80211_ccmp_data
*key
= priv
;
275 struct ieee80211_hdr_4addr
*hdr
;
276 cb_desc
*tcb_desc
= (cb_desc
*)(skb
->cb
+ MAX_DEV_ADDR_SIZE
);
279 if (skb
->len
< hdr_len
+ CCMP_HDR_LEN
+ CCMP_MIC_LEN
) {
280 key
->dot11RSNAStatsCCMPFormatErrors
++;
284 hdr
= (struct ieee80211_hdr_4addr
*) skb
->data
;
285 pos
= skb
->data
+ hdr_len
;
287 if (!(keyidx
& (1 << 5))) {
288 if (net_ratelimit()) {
289 printk(KERN_DEBUG
"CCMP: received packet without ExtIV"
290 " flag from %pM\n", hdr
->addr2
);
292 key
->dot11RSNAStatsCCMPFormatErrors
++;
296 if (key
->key_idx
!= keyidx
) {
297 printk(KERN_DEBUG
"CCMP: RX tkey->key_idx=%d frame "
298 "keyidx=%d priv=%p\n", key
->key_idx
, keyidx
, priv
);
302 if (net_ratelimit()) {
303 printk(KERN_DEBUG
"CCMP: received packet from %pM"
304 " with keyid=%d that does not have a configured"
305 " key\n", hdr
->addr2
, keyidx
);
318 if (memcmp(pn
, key
->rx_pn
, CCMP_PN_LEN
) <= 0) {
319 if (net_ratelimit()) {
320 printk(KERN_DEBUG
"CCMP: replay detected: STA=%pM"
321 " previous PN %pm received PN %pm\n",
322 hdr
->addr2
, key
->rx_pn
, pn
);
324 key
->dot11RSNAStatsCCMPReplays
++;
327 if (!tcb_desc
->bHwSec
)
329 size_t data_len
= skb
->len
- hdr_len
- CCMP_HDR_LEN
- CCMP_MIC_LEN
;
330 u8
*mic
= skb
->data
+ skb
->len
- CCMP_MIC_LEN
;
334 int i
, blocks
, last
, len
;
337 ccmp_init_blocks(key
->tfm
, hdr
, pn
, data_len
, b0
, a
, b
);
338 xor_block(mic
, b
, CCMP_MIC_LEN
);
340 blocks
= (data_len
+ AES_BLOCK_LEN
- 1) / AES_BLOCK_LEN
;
341 last
= data_len
% AES_BLOCK_LEN
;
343 for (i
= 1; i
<= blocks
; i
++) {
344 len
= (i
== blocks
&& last
) ? last
: AES_BLOCK_LEN
;
345 /* Decrypt, with counter */
346 b0
[14] = (i
>> 8) & 0xff;
348 ieee80211_ccmp_aes_encrypt(key
->tfm
, b0
, b
);
349 xor_block(pos
, b
, len
);
351 xor_block(a
, pos
, len
);
352 ieee80211_ccmp_aes_encrypt(key
->tfm
, a
, a
);
356 if (memcmp(mic
, a
, CCMP_MIC_LEN
) != 0) {
357 if (net_ratelimit()) {
358 printk(KERN_DEBUG
"CCMP: decrypt failed: STA="
359 "%pM\n", hdr
->addr2
);
361 key
->dot11RSNAStatsCCMPDecryptErrors
++;
365 memcpy(key
->rx_pn
, pn
, CCMP_PN_LEN
);
367 /* Remove hdr and MIC */
368 memmove(skb
->data
+ CCMP_HDR_LEN
, skb
->data
, hdr_len
);
369 skb_pull(skb
, CCMP_HDR_LEN
);
370 skb_trim(skb
, skb
->len
- CCMP_MIC_LEN
);
376 static int ieee80211_ccmp_set_key(void *key
, int len
, u8
*seq
, void *priv
)
378 struct ieee80211_ccmp_data
*data
= priv
;
380 struct crypto_tfm
*tfm
= data
->tfm
;
382 keyidx
= data
->key_idx
;
383 memset(data
, 0, sizeof(*data
));
384 data
->key_idx
= keyidx
;
386 if (len
== CCMP_TK_LEN
) {
387 memcpy(data
->key
, key
, CCMP_TK_LEN
);
390 data
->rx_pn
[0] = seq
[5];
391 data
->rx_pn
[1] = seq
[4];
392 data
->rx_pn
[2] = seq
[3];
393 data
->rx_pn
[3] = seq
[2];
394 data
->rx_pn
[4] = seq
[1];
395 data
->rx_pn
[5] = seq
[0];
397 crypto_cipher_setkey((void*)data
->tfm
, data
->key
, CCMP_TK_LEN
);
407 static int ieee80211_ccmp_get_key(void *key
, int len
, u8
*seq
, void *priv
)
409 struct ieee80211_ccmp_data
*data
= priv
;
411 if (len
< CCMP_TK_LEN
)
416 memcpy(key
, data
->key
, CCMP_TK_LEN
);
419 seq
[0] = data
->tx_pn
[5];
420 seq
[1] = data
->tx_pn
[4];
421 seq
[2] = data
->tx_pn
[3];
422 seq
[3] = data
->tx_pn
[2];
423 seq
[4] = data
->tx_pn
[1];
424 seq
[5] = data
->tx_pn
[0];
431 static char * ieee80211_ccmp_print_stats(char *p
, void *priv
)
433 struct ieee80211_ccmp_data
*ccmp
= priv
;
434 p
+= sprintf(p
, "key[%d] alg=CCMP key_set=%d "
435 "tx_pn=%pm rx_pn=%pm "
436 "format_errors=%d replays=%d decrypt_errors=%d\n",
437 ccmp
->key_idx
, ccmp
->key_set
,
438 ccmp
->tx_pn
, ccmp
->rx_pn
,
439 ccmp
->dot11RSNAStatsCCMPFormatErrors
,
440 ccmp
->dot11RSNAStatsCCMPReplays
,
441 ccmp
->dot11RSNAStatsCCMPDecryptErrors
);
446 void ieee80211_ccmp_null(void)
448 // printk("============>%s()\n", __FUNCTION__);
452 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp
= {
454 .init
= ieee80211_ccmp_init
,
455 .deinit
= ieee80211_ccmp_deinit
,
456 .encrypt_mpdu
= ieee80211_ccmp_encrypt
,
457 .decrypt_mpdu
= ieee80211_ccmp_decrypt
,
458 .encrypt_msdu
= NULL
,
459 .decrypt_msdu
= NULL
,
460 .set_key
= ieee80211_ccmp_set_key
,
461 .get_key
= ieee80211_ccmp_get_key
,
462 .print_stats
= ieee80211_ccmp_print_stats
,
463 .extra_prefix_len
= CCMP_HDR_LEN
,
464 .extra_postfix_len
= CCMP_MIC_LEN
,
465 .owner
= THIS_MODULE
,
468 int __init
ieee80211_crypto_ccmp_init(void)
470 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp
);
473 void __exit
ieee80211_crypto_ccmp_exit(void)
475 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp
);