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 u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
  81                   const u8 *data, size_t data_len, size_t *decrypted_len)
  82 {
  83         u8 aad[30], nonce[13];
  84         size_t aad_len;
  85         size_t mlen;
  86         u8 *plain;
  87
  88         if (data_len < 8 + 8)
  89                 return NULL;
  90
  91         plain = os_malloc(data_len + AES_BLOCK_SIZE);
  92         if (plain == NULL)
  93                 return NULL;
  94
  95         mlen = data_len - 8 - 8;
  96
  97         os_memset(aad, 0, sizeof(aad));
  98         ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
  99         wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
 100         wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
 101
 102         if (aes_ccm_ad(tk, 16, nonce, 8, data + 8, mlen, aad, aad_len,
 103                        data + 8 + mlen, plain) < 0) {
 104                 u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
 105                 wpa_printf(MSG_INFO, "Invalid CCMP MIC in frame: A1=" MACSTR
 106                            " A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
 107                            MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
 108                            MAC2STR(hdr->addr3),
 109                            WLAN_GET_SEQ_SEQ(seq_ctrl),
 110                            WLAN_GET_SEQ_FRAG(seq_ctrl));
 111                 os_free(plain);
 112                 return NULL;
 113         }
 114         wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
 115
 116         *decrypted_len = mlen;
 117         return plain;
 118 }
 119
 120
 121 void ccmp_get_pn(u8 *pn, const u8 *data)
 122 {
 123         pn[0] = data[7]; /* PN5 */
 124         pn[1] = data[6]; /* PN4 */
 125         pn[2] = data[5]; /* PN3 */
 126         pn[3] = data[4]; /* PN2 */
 127         pn[4] = data[1]; /* PN1 */
 128         pn[5] = data[0]; /* PN0 */
 129 }
 130
 131
 132 u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
 133                   u8 *pn, int keyid, size_t *encrypted_len)
 134 {
 135         u8 aad[30], nonce[13];
 136         size_t aad_len, plen;
 137         u8 *crypt, *pos;
 138         struct ieee80211_hdr *hdr;
 139
 140         if (len < hdrlen || hdrlen < 24)
 141                 return NULL;
 142         plen = len - hdrlen;
 143
 144         crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
 145         if (crypt == NULL)
 146                 return NULL;
 147
 148         os_memcpy(crypt, frame, hdrlen);
 149         hdr = (struct ieee80211_hdr *) crypt;
 150         hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
 151         pos = crypt + hdrlen;
 152         *pos++ = pn[5]; /* PN0 */
 153         *pos++ = pn[4]; /* PN1 */
 154         *pos++ = 0x00; /* Rsvd */
 155         *pos++ = 0x20 | (keyid << 6);
 156         *pos++ = pn[3]; /* PN2 */
 157         *pos++ = pn[2]; /* PN3 */
 158         *pos++ = pn[1]; /* PN4 */
 159         *pos++ = pn[0]; /* PN5 */
 160
 161         os_memset(aad, 0, sizeof(aad));
 162         ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
 163         wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
 164         wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
 165
 166         if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
 167                        pos, pos + plen) < 0) {
 168                 os_free(crypt);
 169                 return NULL;
 170         }
 171
 172         wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen + 8, plen);
 173
 174         *encrypted_len = hdrlen + 8 + plen + 8;
 175
 176         return crypt;
 177 }
 178
 179
 180 u8 * ccmp_256_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
 181                       const u8 *data, size_t data_len, size_t *decrypted_len)
 182 {
 183         u8 aad[30], nonce[13];
 184         size_t aad_len;
 185         size_t mlen;
 186         u8 *plain;
 187
 188         if (data_len < 8 + 16)
 189                 return NULL;
 190
 191         plain = os_malloc(data_len + AES_BLOCK_SIZE);
 192         if (plain == NULL)
 193                 return NULL;
 194
 195         mlen = data_len - 8 - 16;
 196
 197         os_memset(aad, 0, sizeof(aad));
 198         ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
 199         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
 200         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
 201
 202         if (aes_ccm_ad(tk, 32, nonce, 16, data + 8, mlen, aad, aad_len,
 203                        data + 8 + mlen, plain) < 0) {
 204                 u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
 205                 wpa_printf(MSG_INFO, "Invalid CCMP-256 MIC in frame: A1=" MACSTR
 206                            " A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
 207                            MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
 208                            MAC2STR(hdr->addr3),
 209                            WLAN_GET_SEQ_SEQ(seq_ctrl),
 210                            WLAN_GET_SEQ_FRAG(seq_ctrl));
 211                 os_free(plain);
 212                 return NULL;
 213         }
 214         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 decrypted", plain, mlen);
 215
 216         *decrypted_len = mlen;
 217         return plain;
 218 }
 219
 220
 221 u8 * ccmp_256_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
 222                       u8 *qos, u8 *pn, int keyid, size_t *encrypted_len)
 223 {
 224         u8 aad[30], nonce[13];
 225         size_t aad_len, plen;
 226         u8 *crypt, *pos;
 227         struct ieee80211_hdr *hdr;
 228
 229         if (len < hdrlen || hdrlen < 24)
 230                 return NULL;
 231         plen = len - hdrlen;
 232
 233         crypt = os_malloc(hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
 234         if (crypt == NULL)
 235                 return NULL;
 236
 237         os_memcpy(crypt, frame, hdrlen);
 238         hdr = (struct ieee80211_hdr *) crypt;
 239         hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
 240         pos = crypt + hdrlen;
 241         *pos++ = pn[5]; /* PN0 */
 242         *pos++ = pn[4]; /* PN1 */
 243         *pos++ = 0x00; /* Rsvd */
 244         *pos++ = 0x20 | (keyid << 6);
 245         *pos++ = pn[3]; /* PN2 */
 246         *pos++ = pn[2]; /* PN3 */
 247         *pos++ = pn[1]; /* PN4 */
 248         *pos++ = pn[0]; /* PN5 */
 249
 250         os_memset(aad, 0, sizeof(aad));
 251         ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
 252         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
 253         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
 254
 255         if (aes_ccm_ae(tk, 32, nonce, 16, frame + hdrlen, plen, aad, aad_len,
 256                        pos, pos + plen) < 0) {
 257                 os_free(crypt);
 258                 return NULL;
 259         }
 260
 261         wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 encrypted", crypt + hdrlen + 8,
 262                     plen);
 263
 264         *encrypted_len = hdrlen + 8 + plen + 16;
 265
 266         return crypt;
 267 }