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