drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_ccmp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
   4  *
   5  * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/random.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/if_ether.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/string.h>
  17 #include <linux/wireless.h>
  18
  19 #include "ieee80211.h"
  20
  21 #include <linux/crypto.h>
  22 #include <crypto/aead.h>
  23     #include <linux/scatterlist.h>
  24
  25 MODULE_AUTHOR("Jouni Malinen");
  26 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  27 MODULE_LICENSE("GPL");
  28
  29 #define AES_BLOCK_LEN 16
  30 #define CCMP_HDR_LEN 8
  31 #define CCMP_MIC_LEN 8
  32 #define CCMP_TK_LEN 16
  33 #define CCMP_PN_LEN 6
  34
  35 struct ieee80211_ccmp_data {
  36         u8 key[CCMP_TK_LEN];
  37         int key_set;
  38
  39         u8 tx_pn[CCMP_PN_LEN];
  40         u8 rx_pn[CCMP_PN_LEN];
  41
  42         u32 dot11RSNAStatsCCMPFormatErrors;
  43         u32 dot11RSNAStatsCCMPReplays;
  44         u32 dot11RSNAStatsCCMPDecryptErrors;
  45
  46         int key_idx;
  47
  48         struct crypto_aead *tfm;
  49
  50         /* scratch buffers for virt_to_page() (crypto API) */
  51         u8 tx_aad[2 * AES_BLOCK_LEN];
  52         u8 rx_aad[2 * AES_BLOCK_LEN];
  53 };
  54
  55 static void *ieee80211_ccmp_init(int key_idx)
  56 {
  57         struct ieee80211_ccmp_data *priv;
  58
  59         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  60         if (!priv)
  61                 goto fail;
  62         priv->key_idx = key_idx;
  63
  64         priv->tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  65         if (IS_ERR(priv->tfm)) {
  66                 pr_debug("ieee80211_crypt_ccmp: could not allocate crypto API aes\n");
  67                 priv->tfm = NULL;
  68                 goto fail;
  69         }
  70
  71         return priv;
  72
  73 fail:
  74         if (priv) {
  75                 if (priv->tfm)
  76                         crypto_free_aead(priv->tfm);
  77                 kfree(priv);
  78         }
  79
  80         return NULL;
  81 }
  82
  83 static void ieee80211_ccmp_deinit(void *priv)
  84 {
  85         struct ieee80211_ccmp_data *_priv = priv;
  86
  87         if (_priv && _priv->tfm)
  88                 crypto_free_aead(_priv->tfm);
  89         kfree(priv);
  90 }
  91
  92 static int ccmp_init_iv_and_aad(struct rtl_80211_hdr_4addr *hdr,
  93                              u8 *pn, u8 *iv, u8 *aad)
  94 {
  95         u8 *pos, qc = 0;
  96         size_t aad_len;
  97         u16 fc;
  98         int a4_included, qc_included;
  99
 100         fc = le16_to_cpu(hdr->frame_ctl);
 101         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 102                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 103         /* qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 104          *             (WLAN_FC_GET_STYPE(fc) & 0x08));
 105          */
 106         /* fixed by David :2006.9.6 */
 107         qc_included = (WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 108                        (WLAN_FC_GET_STYPE(fc) & 0x80);
 109         aad_len = 22;
 110         if (a4_included)
 111                 aad_len += 6;
 112         if (qc_included) {
 113                 pos = (u8 *)&hdr->addr4;
 114                 if (a4_included)
 115                         pos += 6;
 116                 qc = *pos & 0x0f;
 117                 aad_len += 2;
 118         }
 119
 120         /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
 121          * mode authentication are not allowed to collide, yet both are derived
 122          * from the same vector. We only set L := 1 here to indicate that the
 123          * data size can be represented in (L+1) bytes. The CCM layer will take
 124          * care of storing the data length in the top (L+1) bytes and setting
 125          * and clearing the other bits as is required to derive the two IVs.
 126          */
 127         iv[0] = 0x1;
 128
 129         /* Nonce: QC | A2 | PN */
 130         iv[1] = qc;
 131         memcpy(iv + 2, hdr->addr2, ETH_ALEN);
 132         memcpy(iv + 8, pn, CCMP_PN_LEN);
 133
 134         /* AAD:
 135          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 136          * A1 | A2 | A3
 137          * SC with bits 4..15 (seq#) masked to zero
 138          * A4 (if present)
 139          * QC (if present)
 140          */
 141         pos = (u8 *)hdr;
 142         aad[0] = pos[0] & 0x8f;
 143         aad[1] = pos[1] & 0xc7;
 144         memcpy(aad + 2, hdr->addr1, 3 * ETH_ALEN);
 145         pos = (u8 *)&hdr->seq_ctl;
 146         aad[20] = pos[0] & 0x0f;
 147         aad[21] = 0; /* all bits masked */
 148         memset(aad + 22, 0, 8);
 149         if (a4_included)
 150                 memcpy(aad + 22, hdr->addr4, ETH_ALEN);
 151         if (qc_included) {
 152                 aad[a4_included ? 28 : 22] = qc;
 153                 /* rest of QC masked */
 154         }
 155
 156         return aad_len;
 157 }
 158
 159 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 160 {
 161         struct ieee80211_ccmp_data *key = priv;
 162         int i;
 163         u8 *pos;
 164         struct rtl_80211_hdr_4addr *hdr;
 165         struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 166
 167         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 168             skb_tailroom(skb) < CCMP_MIC_LEN ||
 169             skb->len < hdr_len)
 170                 return -1;
 171
 172         pos = skb_push(skb, CCMP_HDR_LEN);
 173         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 174         pos += hdr_len;
 175         /* mic = skb_put(skb, CCMP_MIC_LEN); */
 176
 177         i = CCMP_PN_LEN - 1;
 178         while (i >= 0) {
 179                 key->tx_pn[i]++;
 180                 if (key->tx_pn[i] != 0)
 181                         break;
 182                 i--;
 183         }
 184
 185         *pos++ = key->tx_pn[5];
 186         *pos++ = key->tx_pn[4];
 187         *pos++ = 0;
 188         *pos++ = (key->key_idx << 6) | BIT(5) /* Ext IV included */;
 189         *pos++ = key->tx_pn[3];
 190         *pos++ = key->tx_pn[2];
 191         *pos++ = key->tx_pn[1];
 192         *pos++ = key->tx_pn[0];
 193
 194         hdr = (struct rtl_80211_hdr_4addr *)skb->data;
 195         if (!tcb_desc->bHwSec) {
 196                 struct aead_request *req;
 197                 struct scatterlist sg[2];
 198                 u8 *aad = key->tx_aad;
 199                 u8 iv[AES_BLOCK_LEN];
 200                 int aad_len, ret;
 201                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;
 202
 203                 req = aead_request_alloc(key->tfm, GFP_ATOMIC);
 204                 if (!req)
 205                         return -ENOMEM;
 206
 207                 aad_len = ccmp_init_iv_and_aad(hdr, key->tx_pn, iv, aad);
 208
 209                 skb_put(skb, CCMP_MIC_LEN);
 210
 211                 sg_init_table(sg, 2);
 212                 sg_set_buf(&sg[0], aad, aad_len);
 213                 sg_set_buf(&sg[1], skb->data + hdr_len + CCMP_HDR_LEN,
 214                            data_len + CCMP_MIC_LEN);
 215
 216                 aead_request_set_callback(req, 0, NULL, NULL);
 217                 aead_request_set_ad(req, aad_len);
 218                 aead_request_set_crypt(req, sg, sg, data_len, iv);
 219
 220                 ret = crypto_aead_encrypt(req);
 221                 aead_request_free(req);
 222
 223                 return ret;
 224         }
 225         return 0;
 226 }
 227
 228 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 229 {
 230         struct ieee80211_ccmp_data *key = priv;
 231         u8 keyidx, *pos;
 232         struct rtl_80211_hdr_4addr *hdr;
 233         struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE);
 234         u8 pn[6];
 235
 236         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 237                 key->dot11RSNAStatsCCMPFormatErrors++;
 238                 return -1;
 239         }
 240
 241         hdr = (struct rtl_80211_hdr_4addr *)skb->data;
 242         pos = skb->data + hdr_len;
 243         keyidx = pos[3];
 244         if (!(keyidx & BIT(5))) {
 245                 if (net_ratelimit()) {
 246                         netdev_dbg(skb->dev, "CCMP: received packet without ExtIV flag from %pM\n",
 247                                    hdr->addr2);
 248                 }
 249                 key->dot11RSNAStatsCCMPFormatErrors++;
 250                 return -2;
 251         }
 252         keyidx >>= 6;
 253         if (key->key_idx != keyidx) {
 254                 netdev_dbg(skb->dev, "CCMP: RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
 255                            key->key_idx, keyidx, priv);
 256                 return -6;
 257         }
 258         if (!key->key_set) {
 259                 if (net_ratelimit()) {
 260                         netdev_dbg(skb->dev, "CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
 261                                    hdr->addr2, keyidx);
 262                 }
 263                 return -3;
 264         }
 265
 266         pn[0] = pos[7];
 267         pn[1] = pos[6];
 268         pn[2] = pos[5];
 269         pn[3] = pos[4];
 270         pn[4] = pos[1];
 271         pn[5] = pos[0];
 272         pos += 8;
 273
 274         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 275                 if (net_ratelimit()) {
 276                         netdev_dbg(skb->dev, "CCMP: replay detected: STA=%pM previous PN %pm received PN %pm\n",
 277                                    hdr->addr2, key->rx_pn, pn);
 278                 }
 279                 key->dot11RSNAStatsCCMPReplays++;
 280                 return -4;
 281         }
 282         if (!tcb_desc->bHwSec) {
 283                 struct aead_request *req;
 284                 struct scatterlist sg[2];
 285                 u8 *aad = key->rx_aad;
 286                 u8 iv[AES_BLOCK_LEN];
 287                 int aad_len, ret;
 288                 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;
 289
 290                 req = aead_request_alloc(key->tfm, GFP_ATOMIC);
 291                 if (!req)
 292                         return -ENOMEM;
 293
 294                 aad_len = ccmp_init_iv_and_aad(hdr, pn, iv, aad);
 295
 296                 sg_init_table(sg, 2);
 297                 sg_set_buf(&sg[0], aad, aad_len);
 298                 sg_set_buf(&sg[1], pos, data_len);
 299
 300                 aead_request_set_callback(req, 0, NULL, NULL);
 301                 aead_request_set_ad(req, aad_len);
 302                 aead_request_set_crypt(req, sg, sg, data_len, iv);
 303
 304                 ret = crypto_aead_decrypt(req);
 305                 aead_request_free(req);
 306
 307                 if (ret) {
 308                         if (net_ratelimit()) {
 309                                 netdev_dbg(skb->dev, "CCMP: decrypt failed: STA=%pM\n",
 310                                            hdr->addr2);
 311                         }
 312                         key->dot11RSNAStatsCCMPDecryptErrors++;
 313                         return -5;
 314                 }
 315
 316                 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 317         }
 318         /* Remove hdr and MIC */
 319         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 320         skb_pull(skb, CCMP_HDR_LEN);
 321         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 322
 323         return keyidx;
 324 }
 325
 326 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 327 {
 328         struct ieee80211_ccmp_data *data = priv;
 329         int keyidx;
 330         struct crypto_aead *tfm = data->tfm;
 331
 332         keyidx = data->key_idx;
 333         memset(data, 0, sizeof(*data));
 334         data->key_idx = keyidx;
 335         if (len == CCMP_TK_LEN) {
 336                 memcpy(data->key, key, CCMP_TK_LEN);
 337                 data->key_set = 1;
 338                 if (seq) {
 339                         data->rx_pn[0] = seq[5];
 340                         data->rx_pn[1] = seq[4];
 341                         data->rx_pn[2] = seq[3];
 342                         data->rx_pn[3] = seq[2];
 343                         data->rx_pn[4] = seq[1];
 344                         data->rx_pn[5] = seq[0];
 345                 }
 346                 if (crypto_aead_setauthsize(tfm, CCMP_MIC_LEN) ||
 347                     crypto_aead_setkey(tfm, data->key, CCMP_TK_LEN))
 348                         return -1;
 349         } else if (len == 0) {
 350                 data->key_set = 0;
 351         } else {
 352                 return -1;
 353         }
 354
 355         return 0;
 356 }
 357
 358 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 359 {
 360         struct ieee80211_ccmp_data *data = priv;
 361
 362         if (len < CCMP_TK_LEN)
 363                 return -1;
 364
 365         if (!data->key_set)
 366                 return 0;
 367         memcpy(key, data->key, CCMP_TK_LEN);
 368
 369         if (seq) {
 370                 seq[0] = data->tx_pn[5];
 371                 seq[1] = data->tx_pn[4];
 372                 seq[2] = data->tx_pn[3];
 373                 seq[3] = data->tx_pn[2];
 374                 seq[4] = data->tx_pn[1];
 375                 seq[5] = data->tx_pn[0];
 376         }
 377
 378         return CCMP_TK_LEN;
 379 }
 380
 381 static char *ieee80211_ccmp_print_stats(char *p, void *priv)
 382 {
 383         struct ieee80211_ccmp_data *ccmp = priv;
 384
 385         p += sprintf(p, "key[%d] alg=CCMP key_set=%d tx_pn=%pm rx_pn=%pm format_errors=%d replays=%d decrypt_errors=%d\n",
 386                      ccmp->key_idx, ccmp->key_set,
 387                      ccmp->tx_pn, ccmp->rx_pn,
 388                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 389                      ccmp->dot11RSNAStatsCCMPReplays,
 390                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 391
 392         return p;
 393 }
 394
 395 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 396         .name                   = "CCMP",
 397         .init                   = ieee80211_ccmp_init,
 398         .deinit                 = ieee80211_ccmp_deinit,
 399         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 400         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 401         .encrypt_msdu           = NULL,
 402         .decrypt_msdu           = NULL,
 403         .set_key                = ieee80211_ccmp_set_key,
 404         .get_key                = ieee80211_ccmp_get_key,
 405         .print_stats            = ieee80211_ccmp_print_stats,
 406         .extra_prefix_len       = CCMP_HDR_LEN,
 407         .extra_postfix_len      = CCMP_MIC_LEN,
 408         .owner                  = THIS_MODULE,
 409 };
 410
 411 int __init ieee80211_crypto_ccmp_init(void)
 412 {
 413         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 414 }
 415
 416 void __exit ieee80211_crypto_ccmp_exit(void)
 417 {
 418         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 419 }