1 /*
2 * CTR with CBC-MAC Protocol (CCMP)
3 * Copyright (c) 2010-2012, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #ifdef CONFIG_IEEE80211W
10
11 #include "utils/includes.h"
12
13 #include "utils/common.h"
14 #include "common/ieee802_11_defs.h"
15 #include "crypto/aes.h"
16 #include "crypto/aes_wrap.h"
17
18
ccmp_aad_nonce(const struct ieee80211_hdr * hdr,const u8 * data,u8 * aad,size_t * aad_len,u8 * nonce)19 static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
20 u8 *aad, size_t *aad_len, u8 *nonce)
21 {
22 u16 fc, stype, seq;
23 int qos = 0, addr4 = 0;
24 u8 *pos;
25
26 nonce[0] = 0;
27
28 fc = le_to_host16(hdr->frame_control);
29 stype = WLAN_FC_GET_STYPE(fc);
30 if ((fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
31 (WLAN_FC_TODS | WLAN_FC_FROMDS))
32 addr4 = 1;
33
34 if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA) {
35 fc &= ~0x0070; /* Mask subtype bits */
36 if (stype & 0x08) {
37 const u8 *qc;
38 qos = 1;
39 fc &= ~WLAN_FC_ORDER;
40 qc = (const u8 *) (hdr + 1);
41 if (addr4)
42 qc += ETH_ALEN;
43 nonce[0] = qc[0] & 0x0f;
44 }
45 } else if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_MGMT)
46 nonce[0] |= 0x10; /* Management */
47
48 fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
49 fc |= WLAN_FC_ISWEP;
50 WPA_PUT_LE16(aad, fc);
51 pos = aad + 2;
52 os_memcpy(pos, hdr->addr1, 3 * ETH_ALEN);
53 pos += 3 * ETH_ALEN;
54 seq = le_to_host16(hdr->seq_ctrl);
55 seq &= ~0xfff0; /* Mask Seq#; do not modify Frag# */
56 WPA_PUT_LE16(pos, seq);
57 pos += 2;
58
59 os_memcpy(pos, hdr + 1, addr4 * ETH_ALEN + qos * 2);
60 pos += addr4 * ETH_ALEN;
61 if (qos) {
62 pos[0] &= ~0x70;
63 if (1 /* FIX: either device has SPP A-MSDU Capab = 0 */)
64 pos[0] &= ~0x80;
65 pos++;
66 *pos++ = 0x00;
67 }
68
69 *aad_len = pos - aad;
70
71 os_memcpy(nonce + 1, hdr->addr2, ETH_ALEN);
72 nonce[7] = data[7]; /* PN5 */
73 nonce[8] = data[6]; /* PN4 */
74 nonce[9] = data[5]; /* PN3 */
75 nonce[10] = data[4]; /* PN2 */
76 nonce[11] = data[1]; /* PN1 */
77 nonce[12] = data[0]; /* PN0 */
78 }
79
80
ccmp_aad_nonce_pv1(const u8 * hdr,const u8 * a1,const u8 * a2,const u8 * a3,const u8 * pn,u8 * aad,size_t * aad_len,u8 * nonce)81 static void ccmp_aad_nonce_pv1(const u8 *hdr, const u8 *a1, const u8 *a2,
82 const u8 *a3, const u8 *pn,
83 u8 *aad, size_t *aad_len, u8 *nonce)
84 {
85 u16 fc, type;
86 u8 *pos;
87
88 nonce[0] = BIT(5); /* PV1 */
89 /* TODO: Priority for QMF; 0 is used for Data frames */
90
91 fc = WPA_GET_LE16(hdr);
92 type = (fc & (BIT(2) | BIT(3) | BIT(4))) >> 2;
93
94 if (type == 1)
95 nonce[0] |= 0x10; /* Management */
96
97 fc &= ~(BIT(10) | BIT(11) | BIT(13) | BIT(14) | BIT(15));
98 fc |= BIT(12);
99 WPA_PUT_LE16(aad, fc);
100 pos = aad + 2;
101 if (type == 0 || type == 3) {
102 const u8 *sc;
103
104 os_memcpy(pos, a1, ETH_ALEN);
105 pos += ETH_ALEN;
106 os_memcpy(pos, a2, ETH_ALEN);
107 pos += ETH_ALEN;
108
109 if (type == 0) {
110 /* Either A1 or A2 contains SID */
111 sc = hdr + 2 + 2 + ETH_ALEN;
112 } else {
113 /* Both A1 and A2 contain full addresses */
114 sc = hdr + 2 + 2 * ETH_ALEN;
115 }
116 /* SC with Sequence Number subfield (bits 4-15 of the Sequence
117 * Control field) masked to 0. */
118 *pos++ = *sc & 0x0f;
119 *pos++ = 0;
120
121 if (a3) {
122 os_memcpy(pos, a3, ETH_ALEN);
123 pos += ETH_ALEN;
124 }
125 }
126
127 *aad_len = pos - aad;
128
129 os_memcpy(nonce + 1, a2, ETH_ALEN);
130 nonce[7] = pn[5]; /* PN5 */
131 nonce[8] = pn[4]; /* PN4 */
132 nonce[9] = pn[3]; /* PN3 */
133 nonce[10] = pn[2]; /* PN2 */
134 nonce[11] = pn[1]; /* PN1 */
135 nonce[12] = pn[0]; /* PN0 */
136 }
137
138
ccmp_decrypt(const u8 * tk,const u8 * hdr,const u8 * data,size_t data_len,size_t * decrypted_len,bool espnow_pkt)139 u8 * ccmp_decrypt(const u8 *tk, const u8 *hdr,
140 const u8 *data, size_t data_len, size_t *decrypted_len, bool espnow_pkt)
141 {
142 u8 aad[30], nonce[13];
143 size_t aad_len;
144 size_t mlen;
145 size_t tag_len = 8;
146 u8 *plain;
147
148 if (data_len < 8 + 8)
149 return NULL;
150
151 plain = os_malloc(data_len + AES_BLOCK_SIZE);
152 if (plain == NULL)
153 return NULL;
154
155 mlen = data_len - 8 - 8;
156
157 os_memset(aad, 0, sizeof(aad));
158 ccmp_aad_nonce((const struct ieee80211_hdr *)hdr, data, aad, &aad_len,
159 nonce);
160 wpa_hexdump(MSG_DEBUG, "CCMP AAD", aad, aad_len);
161 wpa_hexdump(MSG_DEBUG, "CCMP nonce", nonce, 13);
162
163 #ifdef ESPRESSIF_USE
164 if (espnow_pkt) {
165 tag_len = 0;
166 nonce[0] = 0;
167 }
168 #endif
169 if (aes_ccm_ad(tk, 16, nonce, tag_len, data + 8, mlen, aad, aad_len,
170 data + 8 + mlen, plain) < 0) {
171 os_free(plain);
172 return NULL;
173 }
174 wpa_hexdump(MSG_DEBUG, "CCMP decrypted", plain, mlen);
175
176 *decrypted_len = mlen;
177 return plain;
178 }
179
ccmp_get_pn(u8 * pn,const u8 * data)180 void ccmp_get_pn(u8 *pn, const u8 *data)
181 {
182 pn[0] = data[7]; /* PN5 */
183 pn[1] = data[6]; /* PN4 */
184 pn[2] = data[5]; /* PN3 */
185 pn[3] = data[4]; /* PN2 */
186 pn[4] = data[1]; /* PN1 */
187 pn[5] = data[0]; /* PN0 */
188 }
189
190
ccmp_encrypt(const u8 * tk,u8 * frame,size_t len,size_t hdrlen,u8 * pn,int keyid,size_t * encrypted_len)191 u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
192 u8 *pn, int keyid, size_t *encrypted_len)
193 {
194 u8 aad[30], nonce[13];
195 size_t aad_len, plen;
196 u8 *crypt, *pos;
197 struct ieee80211_hdr *hdr;
198
199 if (len < hdrlen || hdrlen < 24)
200 return NULL;
201 plen = len - hdrlen;
202
203 crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
204 if (crypt == NULL)
205 return NULL;
206
207 os_memcpy(crypt, frame, hdrlen);
208 hdr = (struct ieee80211_hdr *) crypt;
209 hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
210 pos = crypt + hdrlen;
211 *pos++ = pn[5]; /* PN0 */
212 *pos++ = pn[4]; /* PN1 */
213 *pos++ = 0x00; /* Rsvd */
214 *pos++ = 0x20 | (keyid << 6);
215 *pos++ = pn[3]; /* PN2 */
216 *pos++ = pn[2]; /* PN3 */
217 *pos++ = pn[1]; /* PN4 */
218 *pos++ = pn[0]; /* PN5 */
219
220 os_memset(aad, 0, sizeof(aad));
221 ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
222 wpa_hexdump(MSG_DEBUG, "CCMP AAD", aad, aad_len);
223 wpa_hexdump(MSG_DEBUG, "CCMP nonce", nonce, 13);
224
225 if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
226 pos, pos + plen) < 0) {
227 wpa_printf(MSG_ERROR, "aes ccm ae failed");
228 os_free(crypt);
229 return NULL;
230 }
231
232 wpa_hexdump(MSG_DEBUG, "CCMP encrypted", crypt + hdrlen + 8, plen);
233
234 *encrypted_len = hdrlen + 8 + plen + 8;
235
236 return crypt;
237 }
238
239
ccmp_encrypt_pv1(const u8 * tk,const u8 * a1,const u8 * a2,const u8 * a3,const u8 * frame,size_t len,size_t hdrlen,const u8 * pn,int keyid,size_t * encrypted_len)240 u8 * ccmp_encrypt_pv1(const u8 *tk, const u8 *a1, const u8 *a2, const u8 *a3,
241 const u8 *frame, size_t len,
242 size_t hdrlen, const u8 *pn, int keyid,
243 size_t *encrypted_len)
244 {
245 u8 aad[24], nonce[13];
246 size_t aad_len, plen;
247 u8 *crypt, *pos;
248 struct ieee80211_hdr *hdr;
249
250 if (len < hdrlen || hdrlen < 12)
251 return NULL;
252 plen = len - hdrlen;
253
254 crypt = os_malloc(hdrlen + plen + 8 + AES_BLOCK_SIZE);
255 if (crypt == NULL)
256 return NULL;
257
258 os_memcpy(crypt, frame, hdrlen);
259 hdr = (struct ieee80211_hdr *) crypt;
260 hdr->frame_control |= host_to_le16(BIT(12)); /* Protected Frame */
261 pos = crypt + hdrlen;
262
263 os_memset(aad, 0, sizeof(aad));
264 ccmp_aad_nonce_pv1(crypt, a1, a2, a3, pn, aad, &aad_len, nonce);
265 wpa_hexdump(MSG_DEBUG, "CCMP AAD", aad, aad_len);
266 wpa_hexdump(MSG_DEBUG, "CCMP nonce", nonce, sizeof(nonce));
267
268 if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
269 pos, pos + plen) < 0) {
270 os_free(crypt);
271 return NULL;
272 }
273
274 wpa_hexdump(MSG_DEBUG, "CCMP encrypted", crypt + hdrlen, plen);
275
276 *encrypted_len = hdrlen + plen + 8;
277
278 return crypt;
279 }
280
281
ccmp_256_decrypt(const u8 * tk,const u8 * hdr,const u8 * data,size_t data_len,size_t * decrypted_len)282 u8 * ccmp_256_decrypt(const u8 *tk, const u8 *hdr, const u8 *data,
283 size_t data_len, size_t *decrypted_len)
284 {
285 u8 aad[30], nonce[13];
286 size_t aad_len;
287 size_t mlen;
288 u8 *plain;
289
290 if (data_len < 8 + 16)
291 return NULL;
292
293 plain = os_malloc(data_len + AES_BLOCK_SIZE);
294 if (plain == NULL)
295 return NULL;
296
297 mlen = data_len - 8 - 16;
298
299 os_memset(aad, 0, sizeof(aad));
300 ccmp_aad_nonce((const struct ieee80211_hdr *)hdr, data, aad,
301 &aad_len, nonce);
302 wpa_hexdump(MSG_DEBUG, "CCMP-256 AAD", aad, aad_len);
303 wpa_hexdump(MSG_DEBUG, "CCMP-256 nonce", nonce, 13);
304
305 if (aes_ccm_ad(tk, 32, nonce, 16, data + 8, mlen, aad, aad_len,
306 data + 8 + mlen, plain) < 0) {
307 os_free(plain);
308 return NULL;
309 }
310 wpa_hexdump(MSG_DEBUG, "CCMP-256 decrypted", plain, mlen);
311
312 *decrypted_len = mlen;
313 return plain;
314 }
315
316
ccmp_256_encrypt(const u8 * tk,u8 * frame,size_t len,size_t hdrlen,u8 * pn,int keyid,size_t * encrypted_len)317 u8 * ccmp_256_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
318 u8 *pn, int keyid, size_t *encrypted_len)
319 {
320 u8 aad[30], nonce[13];
321 size_t aad_len, plen;
322 u8 *crypt, *pos;
323 struct ieee80211_hdr *hdr;
324
325 if (len < hdrlen || hdrlen < 24)
326 return NULL;
327 plen = len - hdrlen;
328
329 crypt = os_malloc(hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
330 if (crypt == NULL)
331 return NULL;
332
333 os_memcpy(crypt, frame, hdrlen);
334 hdr = (struct ieee80211_hdr *) crypt;
335 hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
336 pos = crypt + hdrlen;
337 *pos++ = pn[5]; /* PN0 */
338 *pos++ = pn[4]; /* PN1 */
339 *pos++ = 0x00; /* Rsvd */
340 *pos++ = 0x20 | (keyid << 6);
341 *pos++ = pn[3]; /* PN2 */
342 *pos++ = pn[2]; /* PN3 */
343 *pos++ = pn[1]; /* PN4 */
344 *pos++ = pn[0]; /* PN5 */
345
346 os_memset(aad, 0, sizeof(aad));
347 ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
348 wpa_hexdump(MSG_DEBUG, "CCMP-256 AAD", aad, aad_len);
349 wpa_hexdump(MSG_DEBUG, "CCMP-256 nonce", nonce, 13);
350
351 if (aes_ccm_ae(tk, 32, nonce, 16, frame + hdrlen, plen, aad, aad_len,
352 pos, pos + plen) < 0) {
353 os_free(crypt);
354 return NULL;
355 }
356
357 wpa_hexdump(MSG_DEBUG, "CCMP-256 encrypted", crypt + hdrlen + 8,
358 plen);
359
360 *encrypted_len = hdrlen + 8 + plen + 16;
361
362 return crypt;
363 }
364 #endif /* CONFIG_IEEE80211W */
365
