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8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/slab.h>
11#include <linux/random.h>
12#include <linux/skbuff.h>
13#include <linux/netdevice.h>
14#include <linux/if_ether.h>
15#include <linux/if_arp.h>
16#include <linux/string.h>
17#include <linux/wireless.h>
18
19#include "ieee80211.h"
20
21#include <linux/crypto.h>
22#include <crypto/aead.h>
23 #include <linux/scatterlist.h>
24
25MODULE_AUTHOR("Jouni Malinen");
26MODULE_DESCRIPTION("Host AP crypt: CCMP");
27MODULE_LICENSE("GPL");
28
29#define AES_BLOCK_LEN 16
30#define CCMP_HDR_LEN 8
31#define CCMP_MIC_LEN 8
32#define CCMP_TK_LEN 16
33#define CCMP_PN_LEN 6
34
35struct ieee80211_ccmp_data {
36 u8 key[CCMP_TK_LEN];
37 int key_set;
38
39 u8 tx_pn[CCMP_PN_LEN];
40 u8 rx_pn[CCMP_PN_LEN];
41
42 u32 dot11RSNAStatsCCMPFormatErrors;
43 u32 dot11RSNAStatsCCMPReplays;
44 u32 dot11RSNAStatsCCMPDecryptErrors;
45
46 int key_idx;
47
48 struct crypto_aead *tfm;
49
50
51 u8 tx_aad[2 * AES_BLOCK_LEN];
52 u8 rx_aad[2 * AES_BLOCK_LEN];
53};
54
55static void *ieee80211_ccmp_init(int key_idx)
56{
57 struct ieee80211_ccmp_data *priv;
58
59 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
60 if (!priv)
61 goto fail;
62 priv->key_idx = key_idx;
63
64 priv->tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
65 if (IS_ERR(priv->tfm)) {
66 pr_debug("ieee80211_crypt_ccmp: could not allocate crypto API aes\n");
67 priv->tfm = NULL;
68 goto fail;
69 }
70
71 return priv;
72
73fail:
74 if (priv) {
75 if (priv->tfm)
76 crypto_free_aead(priv->tfm);
77 kfree(priv);
78 }
79
80 return NULL;
81}
82
83static void ieee80211_ccmp_deinit(void *priv)
84{
85 struct ieee80211_ccmp_data *_priv = priv;
86
87 if (_priv && _priv->tfm)
88 crypto_free_aead(_priv->tfm);
89 kfree(priv);
90}
91
92static int ccmp_init_iv_and_aad(struct rtl_80211_hdr_4addr *hdr,
93 u8 *pn, u8 *iv, u8 *aad)
94{
95 u8 *pos, qc = 0;
96 size_t aad_len;
97 u16 fc;
98 int a4_included, qc_included;
99
100 fc = le16_to_cpu(hdr->frame_ctl);
101 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
102 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
103
104
105
106
107 qc_included = (WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
108 (WLAN_FC_GET_STYPE(fc) & 0x80);
109 aad_len = 22;
110 if (a4_included)
111 aad_len += 6;
112 if (qc_included) {
113 pos = (u8 *)&hdr->addr4;
114 if (a4_included)
115 pos += 6;
116 qc = *pos & 0x0f;
117 aad_len += 2;
118 }
119
120
121
122
123
124
125
126
127 iv[0] = 0x1;
128
129
130 iv[1] = qc;
131 memcpy(iv + 2, hdr->addr2, ETH_ALEN);
132 memcpy(iv + 8, pn, CCMP_PN_LEN);
133
134
135
136
137
138
139
140
141 pos = (u8 *)hdr;
142 aad[0] = pos[0] & 0x8f;
143 aad[1] = pos[1] & 0xc7;
144 memcpy(&aad[2], &hdr->addr1, ETH_ALEN);
145 memcpy(&aad[8], &hdr->addr2, ETH_ALEN);
146 memcpy(&aad[14], &hdr->addr3, ETH_ALEN);
147 pos = (u8 *)&hdr->seq_ctl;
148 aad[20] = pos[0] & 0x0f;
149 aad[21] = 0;
150 memset(aad + 22, 0, 8);
151 if (a4_included)
152 memcpy(aad + 22, hdr->addr4, ETH_ALEN);
153 if (qc_included) {
154 aad[a4_included ? 28 : 22] = qc;
155
156 }
157
158 return aad_len;
159}
160
161static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
162{
163 struct ieee80211_ccmp_data *key = priv;
164 int i;
165 u8 *pos;
166 struct rtl_80211_hdr_4addr *hdr;
167 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
168
169 if (skb_headroom(skb) < CCMP_HDR_LEN ||
170 skb_tailroom(skb) < CCMP_MIC_LEN ||
171 skb->len < hdr_len)
172 return -1;
173
174 pos = skb_push(skb, CCMP_HDR_LEN);
175 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
176 pos += hdr_len;
177
178
179 i = CCMP_PN_LEN - 1;
180 while (i >= 0) {
181 key->tx_pn[i]++;
182 if (key->tx_pn[i] != 0)
183 break;
184 i--;
185 }
186
187 *pos++ = key->tx_pn[5];
188 *pos++ = key->tx_pn[4];
189 *pos++ = 0;
190 *pos++ = (key->key_idx << 6) | BIT(5) ;
191 *pos++ = key->tx_pn[3];
192 *pos++ = key->tx_pn[2];
193 *pos++ = key->tx_pn[1];
194 *pos++ = key->tx_pn[0];
195
196 hdr = (struct rtl_80211_hdr_4addr *)skb->data;
197 if (!tcb_desc->bHwSec) {
198 struct aead_request *req;
199 struct scatterlist sg[2];
200 u8 *aad = key->tx_aad;
201 u8 iv[AES_BLOCK_LEN];
202 int aad_len, ret;
203 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;
204
205 req = aead_request_alloc(key->tfm, GFP_ATOMIC);
206 if (!req)
207 return -ENOMEM;
208
209 aad_len = ccmp_init_iv_and_aad(hdr, key->tx_pn, iv, aad);
210
211 skb_put(skb, CCMP_MIC_LEN);
212
213 sg_init_table(sg, 2);
214 sg_set_buf(&sg[0], aad, aad_len);
215 sg_set_buf(&sg[1], skb->data + hdr_len + CCMP_HDR_LEN,
216 data_len + CCMP_MIC_LEN);
217
218 aead_request_set_callback(req, 0, NULL, NULL);
219 aead_request_set_ad(req, aad_len);
220 aead_request_set_crypt(req, sg, sg, data_len, iv);
221
222 ret = crypto_aead_encrypt(req);
223 aead_request_free(req);
224
225 return ret;
226 }
227 return 0;
228}
229
230static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
231{
232 struct ieee80211_ccmp_data *key = priv;
233 u8 keyidx, *pos;
234 struct rtl_80211_hdr_4addr *hdr;
235 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
236 u8 pn[6];
237
238 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
239 key->dot11RSNAStatsCCMPFormatErrors++;
240 return -1;
241 }
242
243 hdr = (struct rtl_80211_hdr_4addr *)skb->data;
244 pos = skb->data + hdr_len;
245 keyidx = pos[3];
246 if (!(keyidx & BIT(5))) {
247 if (net_ratelimit()) {
248 netdev_dbg(skb->dev, "CCMP: received packet without ExtIV flag from %pM\n",
249 hdr->addr2);
250 }
251 key->dot11RSNAStatsCCMPFormatErrors++;
252 return -2;
253 }
254 keyidx >>= 6;
255 if (key->key_idx != keyidx) {
256 netdev_dbg(skb->dev, "CCMP: RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
257 key->key_idx, keyidx, priv);
258 return -6;
259 }
260 if (!key->key_set) {
261 if (net_ratelimit()) {
262 netdev_dbg(skb->dev, "CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
263 hdr->addr2, keyidx);
264 }
265 return -3;
266 }
267
268 pn[0] = pos[7];
269 pn[1] = pos[6];
270 pn[2] = pos[5];
271 pn[3] = pos[4];
272 pn[4] = pos[1];
273 pn[5] = pos[0];
274 pos += 8;
275
276 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
277 if (net_ratelimit()) {
278 netdev_dbg(skb->dev, "CCMP: replay detected: STA=%pM previous PN %pm received PN %pm\n",
279 hdr->addr2, key->rx_pn, pn);
280 }
281 key->dot11RSNAStatsCCMPReplays++;
282 return -4;
283 }
284 if (!tcb_desc->bHwSec) {
285 struct aead_request *req;
286 struct scatterlist sg[2];
287 u8 *aad = key->rx_aad;
288 u8 iv[AES_BLOCK_LEN];
289 int aad_len, ret;
290 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;
291
292 req = aead_request_alloc(key->tfm, GFP_ATOMIC);
293 if (!req)
294 return -ENOMEM;
295
296 aad_len = ccmp_init_iv_and_aad(hdr, pn, iv, aad);
297
298 sg_init_table(sg, 2);
299 sg_set_buf(&sg[0], aad, aad_len);
300 sg_set_buf(&sg[1], pos, data_len);
301
302 aead_request_set_callback(req, 0, NULL, NULL);
303 aead_request_set_ad(req, aad_len);
304 aead_request_set_crypt(req, sg, sg, data_len, iv);
305
306 ret = crypto_aead_decrypt(req);
307 aead_request_free(req);
308
309 if (ret) {
310 if (net_ratelimit()) {
311 netdev_dbg(skb->dev, "CCMP: decrypt failed: STA=%pM\n",
312 hdr->addr2);
313 }
314 key->dot11RSNAStatsCCMPDecryptErrors++;
315 return -5;
316 }
317
318 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
319 }
320
321 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
322 skb_pull(skb, CCMP_HDR_LEN);
323 skb_trim(skb, skb->len - CCMP_MIC_LEN);
324
325 return keyidx;
326}
327
328static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
329{
330 struct ieee80211_ccmp_data *data = priv;
331 int keyidx;
332 struct crypto_aead *tfm = data->tfm;
333
334 keyidx = data->key_idx;
335 memset(data, 0, sizeof(*data));
336 data->key_idx = keyidx;
337 if (len == CCMP_TK_LEN) {
338 memcpy(data->key, key, CCMP_TK_LEN);
339 data->key_set = 1;
340 if (seq) {
341 data->rx_pn[0] = seq[5];
342 data->rx_pn[1] = seq[4];
343 data->rx_pn[2] = seq[3];
344 data->rx_pn[3] = seq[2];
345 data->rx_pn[4] = seq[1];
346 data->rx_pn[5] = seq[0];
347 }
348 if (crypto_aead_setauthsize(tfm, CCMP_MIC_LEN) ||
349 crypto_aead_setkey(tfm, data->key, CCMP_TK_LEN))
350 return -1;
351 } else if (len == 0) {
352 data->key_set = 0;
353 } else {
354 return -1;
355 }
356
357 return 0;
358}
359
360static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
361{
362 struct ieee80211_ccmp_data *data = priv;
363
364 if (len < CCMP_TK_LEN)
365 return -1;
366
367 if (!data->key_set)
368 return 0;
369 memcpy(key, data->key, CCMP_TK_LEN);
370
371 if (seq) {
372 seq[0] = data->tx_pn[5];
373 seq[1] = data->tx_pn[4];
374 seq[2] = data->tx_pn[3];
375 seq[3] = data->tx_pn[2];
376 seq[4] = data->tx_pn[1];
377 seq[5] = data->tx_pn[0];
378 }
379
380 return CCMP_TK_LEN;
381}
382
383static char *ieee80211_ccmp_print_stats(char *p, void *priv)
384{
385 struct ieee80211_ccmp_data *ccmp = priv;
386
387 p += sprintf(p, "key[%d] alg=CCMP key_set=%d tx_pn=%pm rx_pn=%pm format_errors=%d replays=%d decrypt_errors=%d\n",
388 ccmp->key_idx, ccmp->key_set,
389 ccmp->tx_pn, ccmp->rx_pn,
390 ccmp->dot11RSNAStatsCCMPFormatErrors,
391 ccmp->dot11RSNAStatsCCMPReplays,
392 ccmp->dot11RSNAStatsCCMPDecryptErrors);
393
394 return p;
395}
396
397static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
398 .name = "CCMP",
399 .init = ieee80211_ccmp_init,
400 .deinit = ieee80211_ccmp_deinit,
401 .encrypt_mpdu = ieee80211_ccmp_encrypt,
402 .decrypt_mpdu = ieee80211_ccmp_decrypt,
403 .encrypt_msdu = NULL,
404 .decrypt_msdu = NULL,
405 .set_key = ieee80211_ccmp_set_key,
406 .get_key = ieee80211_ccmp_get_key,
407 .print_stats = ieee80211_ccmp_print_stats,
408 .extra_prefix_len = CCMP_HDR_LEN,
409 .extra_postfix_len = CCMP_MIC_LEN,
410 .owner = THIS_MODULE,
411};
412
413int __init ieee80211_crypto_ccmp_init(void)
414{
415 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
416}
417
418void __exit ieee80211_crypto_ccmp_exit(void)
419{
420 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
421}
422
