wlantest/ccmp.c

   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
  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_ORDER;
  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
  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
 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
 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
 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
 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
 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
 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 }