drivers/usb/wusbcore/crypto.c

   1 /*
   2  * Ultra Wide Band
   3  * AES-128 CCM Encryption
   4  *
   5  * Copyright (C) 2007 Intel Corporation
   6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version
  10  * 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20  * 02110-1301, USA.
  21  *
  22  *
  23  * We don't do any encryption here; we use the Linux Kernel's AES-128
  24  * crypto modules to construct keys and payload blocks in a way
  25  * defined by WUSB1.0[6]. Check the erratas, as typos are are patched
  26  * there.
  27  *
  28  * Thanks a zillion to John Keys for his help and clarifications over
  29  * the designed-by-a-committee text.
  30  *
  31  * So the idea is that there is this basic Pseudo-Random-Function
  32  * defined in WUSB1.0[6.5] which is the core of everything. It works
  33  * by tweaking some blocks, AES crypting them and then xoring
  34  * something else with them (this seems to be called CBC(AES) -- can
  35  * you tell I know jack about crypto?). So we just funnel it into the
  36  * Linux Crypto API.
  37  *
  38  * We leave a crypto test module so we can verify that vectors match,
  39  * every now and then.
  40  *
  41  * Block size: 16 bytes -- AES seems to do things in 'block sizes'. I
  42  *             am learning a lot...
  43  *
  44  *             Conveniently, some data structures that need to be
  45  *             funneled through AES are...16 bytes in size!
  46  */
  47
  48 #include <linux/crypto.h>
  49 #include <linux/module.h>
  50 #include <linux/err.h>
  51 #include <linux/uwb.h>
  52 #include <linux/usb/wusb.h>
  53 #include <linux/scatterlist.h>
  54 #define D_LOCAL 0
  55 #include <linux/uwb/debug.h>
  56
  57 static int debug_crypto_verify = 0;
  58
  59 module_param(debug_crypto_verify, int, 0);
  60 MODULE_PARM_DESC(debug_crypto_verify, "verify the key generation algorithms");
  61
  62 /*
  63  * Block of data, as understood by AES-CCM
  64  *
  65  * The code assumes this structure is nothing but a 16 byte array
  66  * (packed in a struct to avoid common mess ups that I usually do with
  67  * arrays and enforcing type checking).
  68  */
  69 struct aes_ccm_block {
  70         u8 data[16];
  71 } __attribute__((packed));
  72
  73 /*
  74  * Counter-mode Blocks (WUSB1.0[6.4])
  75  *
  76  * According to CCM (or so it seems), for the purpose of calculating
  77  * the MIC, the message is broken in N counter-mode blocks, B0, B1,
  78  * ... BN.
  79  *
  80  * B0 contains flags, the CCM nonce and l(m).
  81  *
  82  * B1 contains l(a), the MAC header, the encryption offset and padding.
  83  *
  84  * If EO is nonzero, additional blocks are built from payload bytes
  85  * until EO is exahusted (FIXME: padding to 16 bytes, I guess). The
  86  * padding is not xmitted.
  87  */
  88
  89 /* WUSB1.0[T6.4] */
  90 struct aes_ccm_b0 {
  91         u8 flags;       /* 0x59, per CCM spec */
  92         struct aes_ccm_nonce ccm_nonce;
  93         __be16 lm;
  94 } __attribute__((packed));
  95
  96 /* WUSB1.0[T6.5] */
  97 struct aes_ccm_b1 {
  98         __be16 la;
  99         u8 mac_header[10];
 100         __le16 eo;
 101         u8 security_reserved;   /* This is always zero */
 102         u8 padding;             /* 0 */
 103 } __attribute__((packed));
 104
 105 /*
 106  * Encryption Blocks (WUSB1.0[6.4.4])
 107  *
 108  * CCM uses Ax blocks to generate a keystream with which the MIC and
 109  * the message's payload are encoded. A0 always encrypts/decrypts the
 110  * MIC. Ax (x>0) are used for the sucesive payload blocks.
 111  *
 112  * The x is the counter, and is increased for each block.
 113  */
 114 struct aes_ccm_a {
 115         u8 flags;       /* 0x01, per CCM spec */
 116         struct aes_ccm_nonce ccm_nonce;
 117         __be16 counter; /* Value of x */
 118 } __attribute__((packed));
 119
 120 static void bytewise_xor(void *_bo, const void *_bi1, const void *_bi2,
 121                          size_t size)
 122 {
 123         u8 *bo = _bo;
 124         const u8 *bi1 = _bi1, *bi2 = _bi2;
 125         size_t itr;
 126         for (itr = 0; itr < size; itr++)
 127                 bo[itr] = bi1[itr] ^ bi2[itr];
 128 }
 129
 130 /*
 131  * CC-MAC function WUSB1.0[6.5]
 132  *
 133  * Take a data string and produce the encrypted CBC Counter-mode MIC
 134  *
 135  * Note the names for most function arguments are made to (more or
 136  * less) match those used in the pseudo-function definition given in
 137  * WUSB1.0[6.5].
 138  *
 139  * @tfm_cbc: CBC(AES) blkcipher handle (initialized)
 140  *
 141  * @tfm_aes: AES cipher handle (initialized)
 142  *
 143  * @mic: buffer for placing the computed MIC (Message Integrity
 144  *       Code). This is exactly 8 bytes, and we expect the buffer to
 145  *       be at least eight bytes in length.
 146  *
 147  * @key: 128 bit symmetric key
 148  *
 149  * @n: CCM nonce
 150  *
 151  * @a: ASCII string, 14 bytes long (I guess zero padded if needed;
 152  *     we use exactly 14 bytes).
 153  *
 154  * @b: data stream to be processed; cannot be a global or const local
 155  *     (will confuse the scatterlists)
 156  *
 157  * @blen: size of b...
 158  *
 159  * Still not very clear how this is done, but looks like this: we
 160  * create block B0 (as WUSB1.0[6.5] says), then we AES-crypt it with
 161  * @key. We bytewise xor B0 with B1 (1) and AES-crypt that. Then we
 162  * take the payload and divide it in blocks (16 bytes), xor them with
 163  * the previous crypto result (16 bytes) and crypt it, repeat the next
 164  * block with the output of the previous one, rinse wash (I guess this
 165  * is what AES CBC mode means...but I truly have no idea). So we use
 166  * the CBC(AES) blkcipher, that does precisely that. The IV (Initial
 167  * Vector) is 16 bytes and is set to zero, so
 168  *
 169  * See rfc3610. Linux crypto has a CBC implementation, but the
 170  * documentation is scarce, to say the least, and the example code is
 171  * so intricated that is difficult to understand how things work. Most
 172  * of this is guess work -- bite me.
 173  *
 174  * (1) Created as 6.5 says, again, using as l(a) 'Blen + 14', and
 175  *     using the 14 bytes of @a to fill up
 176  *     b1.{mac_header,e0,security_reserved,padding}.
 177  *
 178  * NOTE: The definiton of l(a) in WUSB1.0[6.5] vs the definition of
 179  *       l(m) is orthogonal, they bear no relationship, so it is not
 180  *       in conflict with the parameter's relation that
 181  *       WUSB1.0[6.4.2]) defines.
 182  *
 183  * NOTE: WUSB1.0[A.1]: Host Nonce is missing a nibble? (1e); fixed in
 184  *       first errata released on 2005/07.
 185  *
 186  * NOTE: we need to clean IV to zero at each invocation to make sure
 187  *       we start with a fresh empty Initial Vector, so that the CBC
 188  *       works ok.
 189  *
 190  * NOTE: blen is not aligned to a block size, we'll pad zeros, that's
 191  *       what sg[4] is for. Maybe there is a smarter way to do this.
 192  */
 193 static int wusb_ccm_mac(struct crypto_blkcipher *tfm_cbc,
 194                         struct crypto_cipher *tfm_aes, void *mic,
 195                         const struct aes_ccm_nonce *n,
 196                         const struct aes_ccm_label *a, const void *b,
 197                         size_t blen)
 198 {
 199         int result = 0;
 200         struct blkcipher_desc desc;
 201         struct aes_ccm_b0 b0;
 202         struct aes_ccm_b1 b1;
 203         struct aes_ccm_a ax;
 204         struct scatterlist sg[4], sg_dst;
 205         void *iv, *dst_buf;
 206         size_t ivsize, dst_size;
 207         const u8 bzero[16] = { 0 };
 208         size_t zero_padding;
 209
 210         d_fnstart(3, NULL, "(tfm_cbc %p, tfm_aes %p, mic %p, "
 211                   "n %p, a %p, b %p, blen %zu)\n",
 212                   tfm_cbc, tfm_aes, mic, n, a, b, blen);
 213         /*
 214          * These checks should be compile time optimized out
 215          * ensure @a fills b1's mac_header and following fields
 216          */
 217         WARN_ON(sizeof(*a) != sizeof(b1) - sizeof(b1.la));
 218         WARN_ON(sizeof(b0) != sizeof(struct aes_ccm_block));
 219         WARN_ON(sizeof(b1) != sizeof(struct aes_ccm_block));
 220         WARN_ON(sizeof(ax) != sizeof(struct aes_ccm_block));
 221
 222         result = -ENOMEM;
 223         zero_padding = sizeof(struct aes_ccm_block)
 224                 - blen % sizeof(struct aes_ccm_block);
 225         zero_padding = blen % sizeof(struct aes_ccm_block);
 226         if (zero_padding)
 227                 zero_padding = sizeof(struct aes_ccm_block) - zero_padding;
 228         dst_size = blen + sizeof(b0) + sizeof(b1) + zero_padding;
 229         dst_buf = kzalloc(dst_size, GFP_KERNEL);
 230         if (dst_buf == NULL) {
 231                 printk(KERN_ERR "E: can't alloc destination buffer\n");
 232                 goto error_dst_buf;
 233         }
 234
 235         iv = crypto_blkcipher_crt(tfm_cbc)->iv;
 236         ivsize = crypto_blkcipher_ivsize(tfm_cbc);
 237         memset(iv, 0, ivsize);
 238
 239         /* Setup B0 */
 240         b0.flags = 0x59;        /* Format B0 */
 241         b0.ccm_nonce = *n;
 242         b0.lm = cpu_to_be16(0); /* WUSB1.0[6.5] sez l(m) is 0 */
 243
 244         /* Setup B1
 245          *
 246          * The WUSB spec is anything but clear! WUSB1.0[6.5]
 247          * says that to initialize B1 from A with 'l(a) = blen +
 248          * 14'--after clarification, it means to use A's contents
 249          * for MAC Header, EO, sec reserved and padding.
 250          */
 251         b1.la = cpu_to_be16(blen + 14);
 252         memcpy(&b1.mac_header, a, sizeof(*a));
 253
 254         d_printf(4, NULL, "I: B0 (%zu bytes)\n", sizeof(b0));
 255         d_dump(4, NULL, &b0, sizeof(b0));
 256         d_printf(4, NULL, "I: B1 (%zu bytes)\n", sizeof(b1));
 257         d_dump(4, NULL, &b1, sizeof(b1));
 258         d_printf(4, NULL, "I: B (%zu bytes)\n", blen);
 259         d_dump(4, NULL, b, blen);
 260         d_printf(4, NULL, "I: B 0-padding (%zu bytes)\n", zero_padding);
 261         d_printf(4, NULL, "D: IV before crypto (%zu)\n", ivsize);
 262         d_dump(4, NULL, iv, ivsize);
 263
 264         sg_init_table(sg, ARRAY_SIZE(sg));
 265         sg_set_buf(&sg[0], &b0, sizeof(b0));
 266         sg_set_buf(&sg[1], &b1, sizeof(b1));
 267         sg_set_buf(&sg[2], b, blen);
 268         /* 0 if well behaved :) */
 269         sg_set_buf(&sg[3], bzero, zero_padding);
 270         sg_init_one(&sg_dst, dst_buf, dst_size);
 271
 272         desc.tfm = tfm_cbc;
 273         desc.flags = 0;
 274         result = crypto_blkcipher_encrypt(&desc, &sg_dst, sg, dst_size);
 275         if (result < 0) {
 276                 printk(KERN_ERR "E: can't compute CBC-MAC tag (MIC): %d\n",
 277                        result);
 278                 goto error_cbc_crypt;
 279         }
 280         d_printf(4, NULL, "D: MIC tag\n");
 281         d_dump(4, NULL, iv, ivsize);
 282
 283         /* Now we crypt the MIC Tag (*iv) with Ax -- values per WUSB1.0[6.5]
 284          * The procedure is to AES crypt the A0 block and XOR the MIC
 285          * Tag agains it; we only do the first 8 bytes and place it
 286          * directly in the destination buffer.
 287          *
 288          * POS Crypto API: size is assumed to be AES's block size.
 289          * Thanks for documenting it -- tip taken from airo.c
 290          */
 291         ax.flags = 0x01;                /* as per WUSB 1.0 spec */
 292         ax.ccm_nonce = *n;
 293         ax.counter = 0;
 294         crypto_cipher_encrypt_one(tfm_aes, (void *)&ax, (void *)&ax);
 295         bytewise_xor(mic, &ax, iv, 8);
 296         d_printf(4, NULL, "D: CTR[MIC]\n");
 297         d_dump(4, NULL, &ax, 8);
 298         d_printf(4, NULL, "D: CCM-MIC tag\n");
 299         d_dump(4, NULL, mic, 8);
 300         result = 8;
 301 error_cbc_crypt:
 302         kfree(dst_buf);
 303 error_dst_buf:
 304         d_fnend(3, NULL, "(tfm_cbc %p, tfm_aes %p, mic %p, "
 305                 "n %p, a %p, b %p, blen %zu)\n",
 306                 tfm_cbc, tfm_aes, mic, n, a, b, blen);
 307         return result;
 308 }
 309
 310 /*
 311  * WUSB Pseudo Random Function (WUSB1.0[6.5])
 312  *
 313  * @b: buffer to the source data; cannot be a global or const local
 314  *     (will confuse the scatterlists)
 315  */
 316 ssize_t wusb_prf(void *out, size_t out_size,
 317                  const u8 key[16], const struct aes_ccm_nonce *_n,
 318                  const struct aes_ccm_label *a,
 319                  const void *b, size_t blen, size_t len)
 320 {
 321         ssize_t result, bytes = 0, bitr;
 322         struct aes_ccm_nonce n = *_n;
 323         struct crypto_blkcipher *tfm_cbc;
 324         struct crypto_cipher *tfm_aes;
 325         u64 sfn = 0;
 326         __le64 sfn_le;
 327
 328         d_fnstart(3, NULL, "(out %p, out_size %zu, key %p, _n %p, "
 329                   "a %p, b %p, blen %zu, len %zu)\n", out, out_size,
 330                   key, _n, a, b, blen, len);
 331
 332         tfm_cbc = crypto_alloc_blkcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
 333         if (IS_ERR(tfm_cbc)) {
 334                 result = PTR_ERR(tfm_cbc);
 335                 printk(KERN_ERR "E: can't load CBC(AES): %d\n", (int)result);
 336                 goto error_alloc_cbc;
 337         }
 338         result = crypto_blkcipher_setkey(tfm_cbc, key, 16);
 339         if (result < 0) {
 340                 printk(KERN_ERR "E: can't set CBC key: %d\n", (int)result);
 341                 goto error_setkey_cbc;
 342         }
 343
 344         tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 345         if (IS_ERR(tfm_aes)) {
 346                 result = PTR_ERR(tfm_aes);
 347                 printk(KERN_ERR "E: can't load AES: %d\n", (int)result);
 348                 goto error_alloc_aes;
 349         }
 350         result = crypto_cipher_setkey(tfm_aes, key, 16);
 351         if (result < 0) {
 352                 printk(KERN_ERR "E: can't set AES key: %d\n", (int)result);
 353                 goto error_setkey_aes;
 354         }
 355
 356         for (bitr = 0; bitr < (len + 63) / 64; bitr++) {
 357                 sfn_le = cpu_to_le64(sfn++);
 358                 memcpy(&n.sfn, &sfn_le, sizeof(n.sfn)); /* n.sfn++... */
 359                 result = wusb_ccm_mac(tfm_cbc, tfm_aes, out + bytes,
 360                                       &n, a, b, blen);
 361                 if (result < 0)
 362                         goto error_ccm_mac;
 363                 bytes += result;
 364         }
 365         result = bytes;
 366 error_ccm_mac:
 367 error_setkey_aes:
 368         crypto_free_cipher(tfm_aes);
 369 error_alloc_aes:
 370 error_setkey_cbc:
 371         crypto_free_blkcipher(tfm_cbc);
 372 error_alloc_cbc:
 373         d_fnend(3, NULL, "(out %p, out_size %zu, key %p, _n %p, "
 374                 "a %p, b %p, blen %zu, len %zu) = %d\n", out, out_size,
 375                 key, _n, a, b, blen, len, (int)bytes);
 376         return result;
 377 }
 378
 379 /* WUSB1.0[A.2] test vectors */
 380 static const u8 stv_hsmic_key[16] = {
 381         0x4b, 0x79, 0xa3, 0xcf, 0xe5, 0x53, 0x23, 0x9d,
 382         0xd7, 0xc1, 0x6d, 0x1c, 0x2d, 0xab, 0x6d, 0x3f
 383 };
 384
 385 static const struct aes_ccm_nonce stv_hsmic_n = {
 386         .sfn = { 0 },
 387         .tkid = { 0x76, 0x98, 0x01,  },
 388         .dest_addr = { .data = { 0xbe, 0x00 } },
 389                 .src_addr = { .data = { 0x76, 0x98 } },
 390 };
 391
 392 /*
 393  * Out-of-band MIC Generation verification code
 394  *
 395  */
 396 static int wusb_oob_mic_verify(void)
 397 {
 398         int result;
 399         u8 mic[8];
 400         /* WUSB1.0[A.2] test vectors
 401          *
 402          * Need to keep it in the local stack as GCC 4.1.3something
 403          * messes up and generates noise.
 404          */
 405         struct usb_handshake stv_hsmic_hs = {
 406                 .bMessageNumber = 2,
 407                 .bStatus        = 00,
 408                 .tTKID          = { 0x76, 0x98, 0x01 },
 409                 .bReserved      = 00,
 410                 .CDID           = { 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
 411                                     0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
 412                                     0x3c, 0x3d, 0x3e, 0x3f },
 413                 .nonce          = { 0x20, 0x21, 0x22, 0x23, 0x24, 0x25,
 414                                     0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
 415                                     0x2c, 0x2d, 0x2e, 0x2f },
 416                 .MIC            = { 0x75, 0x6a, 0x97, 0x51, 0x0c, 0x8c,
 417                                     0x14, 0x7b } ,
 418         };
 419         size_t hs_size;
 420
 421         result = wusb_oob_mic(mic, stv_hsmic_key, &stv_hsmic_n, &stv_hsmic_hs);
 422         if (result < 0)
 423                 printk(KERN_ERR "E: WUSB OOB MIC test: failed: %d\n", result);
 424         else if (memcmp(stv_hsmic_hs.MIC, mic, sizeof(mic))) {
 425                 printk(KERN_ERR "E: OOB MIC test: "
 426                        "mismatch between MIC result and WUSB1.0[A2]\n");
 427                 hs_size = sizeof(stv_hsmic_hs) - sizeof(stv_hsmic_hs.MIC);
 428                 printk(KERN_ERR "E: Handshake2 in: (%zu bytes)\n", hs_size);
 429                 dump_bytes(NULL, &stv_hsmic_hs, hs_size);
 430                 printk(KERN_ERR "E: CCM Nonce in: (%zu bytes)\n",
 431                        sizeof(stv_hsmic_n));
 432                 dump_bytes(NULL, &stv_hsmic_n, sizeof(stv_hsmic_n));
 433                 printk(KERN_ERR "E: MIC out:\n");
 434                 dump_bytes(NULL, mic, sizeof(mic));
 435                 printk(KERN_ERR "E: MIC out (from WUSB1.0[A.2]):\n");
 436                 dump_bytes(NULL, stv_hsmic_hs.MIC, sizeof(stv_hsmic_hs.MIC));
 437                 result = -EINVAL;
 438         } else
 439                 result = 0;
 440         return result;
 441 }
 442
 443 /*
 444  * Test vectors for Key derivation
 445  *
 446  * These come from WUSB1.0[6.5.1], the vectors in WUSB1.0[A.1]
 447  * (errata corrected in 2005/07).
 448  */
 449 static const u8 stv_key_a1[16] __attribute__ ((__aligned__(4))) = {
 450         0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87,
 451         0x78, 0x69, 0x5a, 0x4b, 0x3c, 0x2d, 0x1e, 0x0f
 452 };
 453
 454 static const struct aes_ccm_nonce stv_keydvt_n_a1 = {
 455         .sfn = { 0 },
 456         .tkid = { 0x76, 0x98, 0x01,  },
 457         .dest_addr = { .data = { 0xbe, 0x00 } },
 458         .src_addr = { .data = { 0x76, 0x98 } },
 459 };
 460
 461 static const struct wusb_keydvt_out stv_keydvt_out_a1 = {
 462         .kck = {
 463                 0x4b, 0x79, 0xa3, 0xcf, 0xe5, 0x53, 0x23, 0x9d,
 464                 0xd7, 0xc1, 0x6d, 0x1c, 0x2d, 0xab, 0x6d, 0x3f
 465         },
 466         .ptk = {
 467                 0xc8, 0x70, 0x62, 0x82, 0xb6, 0x7c, 0xe9, 0x06,
 468                 0x7b, 0xc5, 0x25, 0x69, 0xf2, 0x36, 0x61, 0x2d
 469         }
 470 };
 471
 472 /*
 473  * Performa a test to make sure we match the vectors defined in
 474  * WUSB1.0[A.1](Errata2006/12)
 475  */
 476 static int wusb_key_derive_verify(void)
 477 {
 478         int result = 0;
 479         struct wusb_keydvt_out keydvt_out;
 480         /* These come from WUSB1.0[A.1] + 2006/12 errata
 481          * NOTE: can't make this const or global -- somehow it seems
 482          *       the scatterlists for crypto get confused and we get
 483          *       bad data. There is no doc on this... */
 484         struct wusb_keydvt_in stv_keydvt_in_a1 = {
 485                 .hnonce = {
 486                         0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
 487                         0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
 488                 },
 489                 .dnonce = {
 490                         0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
 491                         0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f
 492                 }
 493         };
 494
 495         result = wusb_key_derive(&keydvt_out, stv_key_a1, &stv_keydvt_n_a1,
 496                                  &stv_keydvt_in_a1);
 497         if (result < 0)
 498                 printk(KERN_ERR "E: WUSB key derivation test: "
 499                        "derivation failed: %d\n", result);
 500         if (memcmp(&stv_keydvt_out_a1, &keydvt_out, sizeof(keydvt_out))) {
 501                 printk(KERN_ERR "E: WUSB key derivation test: "
 502                        "mismatch between key derivation result "
 503                        "and WUSB1.0[A1] Errata 2006/12\n");
 504                 printk(KERN_ERR "E: keydvt in: key (%zu bytes)\n",
 505                        sizeof(stv_key_a1));
 506                 dump_bytes(NULL, stv_key_a1, sizeof(stv_key_a1));
 507                 printk(KERN_ERR "E: keydvt in: nonce (%zu bytes)\n",
 508                        sizeof(stv_keydvt_n_a1));
 509                 dump_bytes(NULL, &stv_keydvt_n_a1, sizeof(stv_keydvt_n_a1));
 510                 printk(KERN_ERR "E: keydvt in: hnonce & dnonce (%zu bytes)\n",
 511                        sizeof(stv_keydvt_in_a1));
 512                 dump_bytes(NULL, &stv_keydvt_in_a1, sizeof(stv_keydvt_in_a1));
 513                 printk(KERN_ERR "E: keydvt out: KCK\n");
 514                 dump_bytes(NULL, &keydvt_out.kck, sizeof(keydvt_out.kck));
 515                 printk(KERN_ERR "E: keydvt out: PTK\n");
 516                 dump_bytes(NULL, &keydvt_out.ptk, sizeof(keydvt_out.ptk));
 517                 result = -EINVAL;
 518         } else
 519                 result = 0;
 520         return result;
 521 }
 522
 523 /*
 524  * Initialize crypto system
 525  *
 526  * FIXME: we do nothing now, other than verifying. Later on we'll
 527  * cache the encryption stuff, so that's why we have a separate init.
 528  */
 529 int wusb_crypto_init(void)
 530 {
 531         int result;
 532
 533         if (debug_crypto_verify) {
 534                 result = wusb_key_derive_verify();
 535                 if (result < 0)
 536                         return result;
 537                 return wusb_oob_mic_verify();
 538         }
 539         return 0;
 540 }
 541
 542 void wusb_crypto_exit(void)
 543 {
 544         /* FIXME: free cached crypto transforms */
 545 }