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 #include "utils/includes.h"
10
11 #include "utils/common.h"
12 #include "common/ieee802_11_defs.h"
13 #include "crypto/aes.h"
14 #include "crypto/aes_wrap.h"
15 #include "wlantest.h"
16
17
ccmp_aad_nonce(const struct ieee80211_hdr * hdr,const u8 * data,u8 * aad,size_t * aad_len,u8 * nonce)18 static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
19 u8 *aad, size_t *aad_len, u8 *nonce)
20 {
21 u16 fc, stype, seq;
22 int qos = 0, addr4 = 0;
23 u8 *pos;
24
25 nonce[0] = 0;
26
27 fc = le_to_host16(hdr->frame_control);
28 stype = WLAN_FC_GET_STYPE(fc);
29 if ((fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
30 (WLAN_FC_TODS | WLAN_FC_FROMDS))
31 addr4 = 1;
32
33 if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA) {
34 fc &= ~0x0070; /* Mask subtype bits */
35 if (stype & 0x08) {
36 const u8 *qc;
37 qos = 1;
38 fc &= ~WLAN_FC_HTC;
39 qc = (const u8 *) (hdr + 1);
40 if (addr4)
41 qc += ETH_ALEN;
42 nonce[0] = qc[0] & 0x0f;
43 }
44 } else if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_MGMT)
45 nonce[0] |= 0x10; /* Management */
46
47 fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
48 fc |= WLAN_FC_ISWEP;
49 WPA_PUT_LE16(aad, fc);
50 pos = aad + 2;
51 os_memcpy(pos, hdr->addr1, 3 * ETH_ALEN);
52 pos += 3 * ETH_ALEN;
53 seq = le_to_host16(hdr->seq_ctrl);
54 seq &= ~0xfff0; /* Mask Seq#; do not modify Frag# */
55 WPA_PUT_LE16(pos, seq);
56 pos += 2;
57
58 os_memcpy(pos, hdr + 1, addr4 * ETH_ALEN + qos * 2);
59 pos += addr4 * ETH_ALEN;
60 if (qos) {
61 pos[0] &= ~0x70;
62 if (1 /* FIX: either device has SPP A-MSDU Capab = 0 */)
63 pos[0] &= ~0x80;
64 pos++;
65 *pos++ = 0x00;
66 }
67
68 *aad_len = pos - aad;
69
70 os_memcpy(nonce + 1, hdr->addr2, ETH_ALEN);
71 nonce[7] = data[7]; /* PN5 */
72 nonce[8] = data[6]; /* PN4 */
73 nonce[9] = data[5]; /* PN3 */
74 nonce[10] = data[4]; /* PN2 */
75 nonce[11] = data[1]; /* PN1 */
76 nonce[12] = data[0]; /* PN0 */
77 }
78
79
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)80 static void ccmp_aad_nonce_pv1(const u8 *hdr, const u8 *a1, const u8 *a2,
81 const u8 *a3, const u8 *pn,
82 u8 *aad, size_t *aad_len, u8 *nonce)
83 {
84 u16 fc, type;
85 u8 *pos;
86
87 nonce[0] = BIT(5); /* PV1 */
88 /* TODO: Priority for QMF; 0 is used for Data frames */
89
90 fc = WPA_GET_LE16(hdr);
91 type = (fc & (BIT(2) | BIT(3) | BIT(4))) >> 2;
92
93 if (type == 1)
94 nonce[0] |= 0x10; /* Management */
95
96 fc &= ~(BIT(10) | BIT(11) | BIT(13) | BIT(14) | BIT(15));
97 fc |= BIT(12);
98 WPA_PUT_LE16(aad, fc);
99 pos = aad + 2;
100 if (type == 0 || type == 3) {
101 const u8 *sc;
102
103 os_memcpy(pos, a1, ETH_ALEN);
104 pos += ETH_ALEN;
105 os_memcpy(pos, a2, ETH_ALEN);
106 pos += ETH_ALEN;
107
108 if (type == 0) {
109 /* Either A1 or A2 contains SID */
110 sc = hdr + 2 + 2 + ETH_ALEN;
111 } else {
112 /* Both A1 and A2 contain full addresses */
113 sc = hdr + 2 + 2 * ETH_ALEN;
114 }
115 /* SC with Sequence Number subfield (bits 4-15 of the Sequence
116 * Control field) masked to 0. */
117 *pos++ = *sc & 0x0f;
118 *pos++ = 0;
119
120 if (a3) {
121 os_memcpy(pos, a3, ETH_ALEN);
122 pos += ETH_ALEN;
123 }
124 }
125
126 *aad_len = pos - aad;
127
128 os_memcpy(nonce + 1, a2, ETH_ALEN);
129 nonce[7] = pn[5]; /* PN5 */
130 nonce[8] = pn[4]; /* PN4 */
131 nonce[9] = pn[3]; /* PN3 */
132 nonce[10] = pn[2]; /* PN2 */
133 nonce[11] = pn[1]; /* PN1 */
134 nonce[12] = pn[0]; /* PN0 */
135 }
136
137
ccmp_decrypt(const u8 * tk,const struct ieee80211_hdr * hdr,const u8 * data,size_t data_len,size_t * decrypted_len)138 u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
139 const u8 *data, size_t data_len, size_t *decrypted_len)
140 {
141 u8 aad[30], nonce[13];
142 size_t aad_len;
143 size_t mlen;
144 u8 *plain;
145
146 if (data_len < 8 + 8)
147 return NULL;
148
149 plain = os_malloc(data_len + AES_BLOCK_SIZE);
150 if (plain == NULL)
151 return NULL;
152
153 mlen = data_len - 8 - 8;
154
155 os_memset(aad, 0, sizeof(aad));
156 ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
157 wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
158 wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
159
160 if (aes_ccm_ad(tk, 16, nonce, 8, data + 8, mlen, aad, aad_len,
161 data + 8 + mlen, plain) < 0) {
162 u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
163 wpa_printf(MSG_INFO, "Invalid CCMP MIC in frame: A1=" MACSTR
164 " A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
165 MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
166 MAC2STR(hdr->addr3),
167 WLAN_GET_SEQ_SEQ(seq_ctrl),
168 WLAN_GET_SEQ_FRAG(seq_ctrl));
169 os_free(plain);
170 return NULL;
171 }
172 wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
173
174 *decrypted_len = mlen;
175 return plain;
176 }
177
178
ccmp_get_pn(u8 * pn,const u8 * data)179 void ccmp_get_pn(u8 *pn, const u8 *data)
180 {
181 pn[0] = data[7]; /* PN5 */
182 pn[1] = data[6]; /* PN4 */
183 pn[2] = data[5]; /* PN3 */
184 pn[3] = data[4]; /* PN2 */
185 pn[4] = data[1]; /* PN1 */
186 pn[5] = data[0]; /* PN0 */
187 }
188
189
ccmp_encrypt(const u8 * tk,u8 * frame,size_t len,size_t hdrlen,u8 * qos,u8 * pn,int keyid,size_t * encrypted_len)190 u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
191 u8 *pn, int keyid, size_t *encrypted_len)
192 {
193 u8 aad[30], nonce[13];
194 size_t aad_len, plen;
195 u8 *crypt, *pos;
196 struct ieee80211_hdr *hdr;
197
198 if (len < hdrlen || hdrlen < 24)
199 return NULL;
200 plen = len - hdrlen;
201
202 crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
203 if (crypt == NULL)
204 return NULL;
205
206 os_memcpy(crypt, frame, hdrlen);
207 hdr = (struct ieee80211_hdr *) crypt;
208 hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
209 pos = crypt + hdrlen;
210 *pos++ = pn[5]; /* PN0 */
211 *pos++ = pn[4]; /* PN1 */
212 *pos++ = 0x00; /* Rsvd */
213 *pos++ = 0x20 | (keyid << 6);
214 *pos++ = pn[3]; /* PN2 */
215 *pos++ = pn[2]; /* PN3 */
216 *pos++ = pn[1]; /* PN4 */
217 *pos++ = pn[0]; /* PN5 */
218
219 os_memset(aad, 0, sizeof(aad));
220 ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
221 wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
222 wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
223
224 if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
225 pos, pos + plen) < 0) {
226 os_free(crypt);
227 return NULL;
228 }
229
230 wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen + 8, plen);
231
232 *encrypted_len = hdrlen + 8 + plen + 8;
233
234 return crypt;
235 }
236
237
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)238 u8 * ccmp_encrypt_pv1(const u8 *tk, const u8 *a1, const u8 *a2, const u8 *a3,
239 const u8 *frame, size_t len,
240 size_t hdrlen, const u8 *pn, int keyid,
241 size_t *encrypted_len)
242 {
243 u8 aad[24], nonce[13];
244 size_t aad_len, plen;
245 u8 *crypt, *pos;
246 struct ieee80211_hdr *hdr;
247
248 if (len < hdrlen || hdrlen < 12)
249 return NULL;
250 plen = len - hdrlen;
251
252 crypt = os_malloc(hdrlen + plen + 8 + AES_BLOCK_SIZE);
253 if (crypt == NULL)
254 return NULL;
255
256 os_memcpy(crypt, frame, hdrlen);
257 hdr = (struct ieee80211_hdr *) crypt;
258 hdr->frame_control |= host_to_le16(BIT(12)); /* Protected Frame */
259 pos = crypt + hdrlen;
260
261 os_memset(aad, 0, sizeof(aad));
262 ccmp_aad_nonce_pv1(crypt, a1, a2, a3, pn, aad, &aad_len, nonce);
263 wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
264 wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, sizeof(nonce));
265
266 if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
267 pos, pos + plen) < 0) {
268 os_free(crypt);
269 return NULL;
270 }
271
272 wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen, plen);
273
274 *encrypted_len = hdrlen + plen + 8;
275
276 return crypt;
277 }
278
279
ccmp_256_decrypt(const u8 * tk,const struct ieee80211_hdr * hdr,const u8 * data,size_t data_len,size_t * decrypted_len)280 u8 * ccmp_256_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
281 const u8 *data, size_t data_len, size_t *decrypted_len)
282 {
283 u8 aad[30], nonce[13];
284 size_t aad_len;
285 size_t mlen;
286 u8 *plain;
287
288 if (data_len < 8 + 16)
289 return NULL;
290
291 plain = os_malloc(data_len + AES_BLOCK_SIZE);
292 if (plain == NULL)
293 return NULL;
294
295 mlen = data_len - 8 - 16;
296
297 os_memset(aad, 0, sizeof(aad));
298 ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
299 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
300 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
301
302 if (aes_ccm_ad(tk, 32, nonce, 16, data + 8, mlen, aad, aad_len,
303 data + 8 + mlen, plain) < 0) {
304 u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
305 wpa_printf(MSG_INFO, "Invalid CCMP-256 MIC in frame: A1=" MACSTR
306 " A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
307 MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
308 MAC2STR(hdr->addr3),
309 WLAN_GET_SEQ_SEQ(seq_ctrl),
310 WLAN_GET_SEQ_FRAG(seq_ctrl));
311 os_free(plain);
312 return NULL;
313 }
314 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 decrypted", plain, mlen);
315
316 *decrypted_len = mlen;
317 return plain;
318 }
319
320
ccmp_256_encrypt(const u8 * tk,u8 * frame,size_t len,size_t hdrlen,u8 * qos,u8 * pn,int keyid,size_t * encrypted_len)321 u8 * ccmp_256_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
322 u8 *qos, u8 *pn, int keyid, size_t *encrypted_len)
323 {
324 u8 aad[30], nonce[13];
325 size_t aad_len, plen;
326 u8 *crypt, *pos;
327 struct ieee80211_hdr *hdr;
328
329 if (len < hdrlen || hdrlen < 24)
330 return NULL;
331 plen = len - hdrlen;
332
333 crypt = os_malloc(hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
334 if (crypt == NULL)
335 return NULL;
336
337 os_memcpy(crypt, frame, hdrlen);
338 hdr = (struct ieee80211_hdr *) crypt;
339 hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
340 pos = crypt + hdrlen;
341 *pos++ = pn[5]; /* PN0 */
342 *pos++ = pn[4]; /* PN1 */
343 *pos++ = 0x00; /* Rsvd */
344 *pos++ = 0x20 | (keyid << 6);
345 *pos++ = pn[3]; /* PN2 */
346 *pos++ = pn[2]; /* PN3 */
347 *pos++ = pn[1]; /* PN4 */
348 *pos++ = pn[0]; /* PN5 */
349
350 os_memset(aad, 0, sizeof(aad));
351 ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
352 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
353 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
354
355 if (aes_ccm_ae(tk, 32, nonce, 16, frame + hdrlen, plen, aad, aad_len,
356 pos, pos + plen) < 0) {
357 os_free(crypt);
358 return NULL;
359 }
360
361 wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 encrypted", crypt + hdrlen + 8,
362 plen);
363
364 *encrypted_len = hdrlen + 8 + plen + 16;
365
366 return crypt;
367 }
368