drivers/staging/rtl8187se/ieee80211/ieee80211_crypt_ccmp.c

   1 /*
   2  * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
   3  *
   4  * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation. See README and COPYING for
   9  * more details.
  10  */
  11
  12 //#include <linux/config.h>
  13 #include <linux/version.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/random.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/if_ether.h>
  21 #include <linux/if_arp.h>
  22 #include <asm/string.h>
  23 #include <linux/wireless.h>
  24
  25 #include "ieee80211.h"
  26
  27 #include <linux/crypto.h>
  28 #include <linux/scatterlist.h>
  29
  30 MODULE_AUTHOR("Jouni Malinen");
  31 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  32 MODULE_LICENSE("GPL");
  33
  34
  35 #define AES_BLOCK_LEN 16
  36 #define CCMP_HDR_LEN 8
  37 #define CCMP_MIC_LEN 8
  38 #define CCMP_TK_LEN 16
  39 #define CCMP_PN_LEN 6
  40
  41 struct ieee80211_ccmp_data {
  42         u8 key[CCMP_TK_LEN];
  43         int key_set;
  44
  45         u8 tx_pn[CCMP_PN_LEN];
  46         u8 rx_pn[CCMP_PN_LEN];
  47
  48         u32 dot11RSNAStatsCCMPFormatErrors;
  49         u32 dot11RSNAStatsCCMPReplays;
  50         u32 dot11RSNAStatsCCMPDecryptErrors;
  51
  52         int key_idx;
  53
  54         struct crypto_tfm *tfm;
  55
  56         /* scratch buffers for virt_to_page() (crypto API) */
  57         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  58                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  59         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  60 };
  61
  62 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  63                              const u8 pt[16], u8 ct[16])
  64 {
  65         crypto_cipher_encrypt_one((void *)tfm, ct, pt);
  66 }
  67
  68 static void * ieee80211_ccmp_init(int key_idx)
  69 {
  70         struct ieee80211_ccmp_data *priv;
  71
  72         priv = kmalloc(sizeof(*priv), GFP_ATOMIC);
  73         if (priv == NULL)
  74                 goto fail;
  75         memset(priv, 0, sizeof(*priv));
  76         priv->key_idx = key_idx;
  77
  78         priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  79         if (IS_ERR(priv->tfm)) {
  80                 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate "
  81                        "crypto API aes\n");
  82                 priv->tfm = NULL;
  83                 goto fail;
  84         }
  85
  86         return priv;
  87
  88 fail:
  89         if (priv) {
  90                 if (priv->tfm)
  91                         crypto_free_cipher((void *)priv->tfm);
  92                 kfree(priv);
  93         }
  94
  95         return NULL;
  96 }
  97
  98
  99 static void ieee80211_ccmp_deinit(void *priv)
 100 {
 101         struct ieee80211_ccmp_data *_priv = priv;
 102
 103         if (_priv && _priv->tfm)
 104                 crypto_free_cipher((void *)_priv->tfm);
 105         kfree(priv);
 106 }
 107
 108
 109 static inline void xor_block(u8 *b, u8 *a, size_t len)
 110 {
 111         int i;
 112         for (i = 0; i < len; i++)
 113                 b[i] ^= a[i];
 114 }
 115
 116 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 117                              struct ieee80211_hdr_4addr *hdr,
 118                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 119                              u8 *s0)
 120 {
 121         u8 *pos, qc = 0;
 122         size_t aad_len;
 123         u16 fc;
 124         int a4_included, qc_included;
 125         u8 aad[2 * AES_BLOCK_LEN];
 126
 127         fc = le16_to_cpu(hdr->frame_ctl);
 128         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 129                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 130         /*
 131         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 132                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 133         */
 134         // fixed by David :2006.9.6
 135         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 136                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 137         aad_len = 22;
 138         if (a4_included)
 139                 aad_len += 6;
 140         if (qc_included) {
 141                 pos = (u8 *) &hdr->addr4;
 142                 if (a4_included)
 143                         pos += 6;
 144                 qc = *pos & 0x0f;
 145                 aad_len += 2;
 146         }
 147         /* CCM Initial Block:
 148          * Flag (Include authentication header, M=3 (8-octet MIC),
 149          *       L=1 (2-octet Dlen))
 150          * Nonce: 0x00 | A2 | PN
 151          * Dlen */
 152         b0[0] = 0x59;
 153         b0[1] = qc;
 154         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 155         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 156         b0[14] = (dlen >> 8) & 0xff;
 157         b0[15] = dlen & 0xff;
 158
 159         /* AAD:
 160          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 161          * A1 | A2 | A3
 162          * SC with bits 4..15 (seq#) masked to zero
 163          * A4 (if present)
 164          * QC (if present)
 165          */
 166         pos = (u8 *) hdr;
 167         aad[0] = 0; /* aad_len >> 8 */
 168         aad[1] = aad_len & 0xff;
 169         aad[2] = pos[0] & 0x8f;
 170         aad[3] = pos[1] & 0xc7;
 171         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 172         pos = (u8 *) &hdr->seq_ctl;
 173         aad[22] = pos[0] & 0x0f;
 174         aad[23] = 0; /* all bits masked */
 175         memset(aad + 24, 0, 8);
 176         if (a4_included)
 177                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 178         if (qc_included) {
 179                 aad[a4_included ? 30 : 24] = qc;
 180                 /* rest of QC masked */
 181         }
 182
 183         /* Start with the first block and AAD */
 184         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 185         xor_block(auth, aad, AES_BLOCK_LEN);
 186         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 187         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 188         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 189         b0[0] &= 0x07;
 190         b0[14] = b0[15] = 0;
 191         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 192 }
 193
 194 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 195 {
 196         struct ieee80211_ccmp_data *key = priv;
 197         int data_len, i;
 198         u8 *pos;
 199         struct ieee80211_hdr_4addr *hdr;
 200         int blocks, last, len;
 201         u8 *mic;
 202         u8 *b0 = key->tx_b0;
 203         u8 *b = key->tx_b;
 204         u8 *e = key->tx_e;
 205         u8 *s0 = key->tx_s0;
 206
 207         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 208             skb_tailroom(skb) < CCMP_MIC_LEN ||
 209             skb->len < hdr_len)
 210                 return -1;
 211
 212         data_len = skb->len - hdr_len;
 213         pos = skb_push(skb, CCMP_HDR_LEN);
 214         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 215         pos += hdr_len;
 216 //      mic = skb_put(skb, CCMP_MIC_LEN);
 217
 218         i = CCMP_PN_LEN - 1;
 219         while (i >= 0) {
 220                 key->tx_pn[i]++;
 221                 if (key->tx_pn[i] != 0)
 222                         break;
 223                 i--;
 224         }
 225
 226         *pos++ = key->tx_pn[5];
 227         *pos++ = key->tx_pn[4];
 228         *pos++ = 0;
 229         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 230         *pos++ = key->tx_pn[3];
 231         *pos++ = key->tx_pn[2];
 232         *pos++ = key->tx_pn[1];
 233         *pos++ = key->tx_pn[0];
 234
 235         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 236         //mic is moved to here by john
 237         mic = skb_put(skb, CCMP_MIC_LEN);
 238
 239         ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 240
 241         blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 242         last = data_len % AES_BLOCK_LEN;
 243
 244         for (i = 1; i <= blocks; i++) {
 245                 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 246                 /* Authentication */
 247                 xor_block(b, pos, len);
 248                 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 249                 /* Encryption, with counter */
 250                 b0[14] = (i >> 8) & 0xff;
 251                 b0[15] = i & 0xff;
 252                 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 253                 xor_block(pos, e, len);
 254                 pos += len;
 255         }
 256
 257         for (i = 0; i < CCMP_MIC_LEN; i++)
 258                 mic[i] = b[i] ^ s0[i];
 259
 260         return 0;
 261 }
 262
 263
 264 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 265 {
 266         struct ieee80211_ccmp_data *key = priv;
 267         u8 keyidx, *pos;
 268         struct ieee80211_hdr_4addr *hdr;
 269         u8 pn[6];
 270         size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 271         u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 272         u8 *b0 = key->rx_b0;
 273         u8 *b = key->rx_b;
 274         u8 *a = key->rx_a;
 275         int i, blocks, last, len;
 276
 277         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 278                 key->dot11RSNAStatsCCMPFormatErrors++;
 279                 return -1;
 280         }
 281
 282         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 283         pos = skb->data + hdr_len;
 284         keyidx = pos[3];
 285         if (!(keyidx & (1 << 5))) {
 286                 if (net_ratelimit()) {
 287                         printk(KERN_DEBUG "CCMP: received packet without ExtIV"
 288                                " flag from %pM\n", hdr->addr2);
 289                 }
 290                 key->dot11RSNAStatsCCMPFormatErrors++;
 291                 return -2;
 292         }
 293         keyidx >>= 6;
 294         if (key->key_idx != keyidx) {
 295                 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame "
 296                        "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv);
 297                 return -6;
 298         }
 299         if (!key->key_set) {
 300                 if (net_ratelimit()) {
 301                         printk(KERN_DEBUG "CCMP: received packet from %pM"
 302                                " with keyid=%d that does not have a configured"
 303                                " key\n", hdr->addr2, keyidx);
 304                 }
 305                 return -3;
 306         }
 307
 308         pn[0] = pos[7];
 309         pn[1] = pos[6];
 310         pn[2] = pos[5];
 311         pn[3] = pos[4];
 312         pn[4] = pos[1];
 313         pn[5] = pos[0];
 314         pos += 8;
 315
 316         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 317                 if (net_ratelimit()) {
 318                         printk(KERN_DEBUG "CCMP: replay detected: STA=%pM"
 319                                " previous PN %pm received PN %pm\n",
 320                                hdr->addr2, key->rx_pn, pn);
 321                 }
 322                 key->dot11RSNAStatsCCMPReplays++;
 323                 return -4;
 324         }
 325
 326         ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 327         xor_block(mic, b, CCMP_MIC_LEN);
 328
 329         blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 330         last = data_len % AES_BLOCK_LEN;
 331
 332         for (i = 1; i <= blocks; i++) {
 333                 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 334                 /* Decrypt, with counter */
 335                 b0[14] = (i >> 8) & 0xff;
 336                 b0[15] = i & 0xff;
 337                 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 338                 xor_block(pos, b, len);
 339                 /* Authentication */
 340                 xor_block(a, pos, len);
 341                 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 342                 pos += len;
 343         }
 344
 345         if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 346                 if (net_ratelimit()) {
 347                         printk(KERN_DEBUG "CCMP: decrypt failed: STA="
 348                                "%pM\n", hdr->addr2);
 349                 }
 350                 key->dot11RSNAStatsCCMPDecryptErrors++;
 351                 return -5;
 352         }
 353
 354         memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 355
 356         /* Remove hdr and MIC */
 357         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 358         skb_pull(skb, CCMP_HDR_LEN);
 359         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 360
 361         return keyidx;
 362 }
 363
 364
 365 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 366 {
 367         struct ieee80211_ccmp_data *data = priv;
 368         int keyidx;
 369         struct crypto_tfm *tfm = data->tfm;
 370
 371         keyidx = data->key_idx;
 372         memset(data, 0, sizeof(*data));
 373         data->key_idx = keyidx;
 374         data->tfm = tfm;
 375         if (len == CCMP_TK_LEN) {
 376                 memcpy(data->key, key, CCMP_TK_LEN);
 377                 data->key_set = 1;
 378                 if (seq) {
 379                         data->rx_pn[0] = seq[5];
 380                         data->rx_pn[1] = seq[4];
 381                         data->rx_pn[2] = seq[3];
 382                         data->rx_pn[3] = seq[2];
 383                         data->rx_pn[4] = seq[1];
 384                         data->rx_pn[5] = seq[0];
 385                 }
 386                 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
 387         } else if (len == 0)
 388                 data->key_set = 0;
 389         else
 390                 return -1;
 391
 392         return 0;
 393 }
 394
 395
 396 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 397 {
 398         struct ieee80211_ccmp_data *data = priv;
 399
 400         if (len < CCMP_TK_LEN)
 401                 return -1;
 402
 403         if (!data->key_set)
 404                 return 0;
 405         memcpy(key, data->key, CCMP_TK_LEN);
 406
 407         if (seq) {
 408                 seq[0] = data->tx_pn[5];
 409                 seq[1] = data->tx_pn[4];
 410                 seq[2] = data->tx_pn[3];
 411                 seq[3] = data->tx_pn[2];
 412                 seq[4] = data->tx_pn[1];
 413                 seq[5] = data->tx_pn[0];
 414         }
 415
 416         return CCMP_TK_LEN;
 417 }
 418
 419
 420 static char * ieee80211_ccmp_print_stats(char *p, void *priv)
 421 {
 422         struct ieee80211_ccmp_data *ccmp = priv;
 423         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 424                      "tx_pn=%pm rx_pn=%pm "
 425                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 426                      ccmp->key_idx, ccmp->key_set,
 427                      ccmp->tx_pn, ccmp->rx_pn,
 428                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 429                      ccmp->dot11RSNAStatsCCMPReplays,
 430                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 431
 432         return p;
 433 }
 434
 435 void ieee80211_ccmp_null(void)
 436 {
 437 //    printk("============>%s()\n", __func__);
 438         return;
 439 }
 440 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 441         .name                   = "CCMP",
 442         .init                   = ieee80211_ccmp_init,
 443         .deinit                 = ieee80211_ccmp_deinit,
 444         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 445         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 446         .encrypt_msdu           = NULL,
 447         .decrypt_msdu           = NULL,
 448         .set_key                = ieee80211_ccmp_set_key,
 449         .get_key                = ieee80211_ccmp_get_key,
 450         .print_stats            = ieee80211_ccmp_print_stats,
 451         .extra_prefix_len       = CCMP_HDR_LEN,
 452         .extra_postfix_len      = CCMP_MIC_LEN,
 453         .owner                  = THIS_MODULE,
 454 };
 455
 456
 457 int ieee80211_crypto_ccmp_init(void)
 458 {
 459         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 460 }
 461
 462
 463 void ieee80211_crypto_ccmp_exit(void)
 464 {
 465         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 466 }