crypto/vmac.c

   1 /*
   2  * VMAC: Message Authentication Code using Universal Hashing
   3  *
   4  * Reference: https://tools.ietf.org/html/draft-krovetz-vmac-01
   5  *
   6  * Copyright (c) 2009, Intel Corporation.
   7  * Copyright (c) 2018, Google Inc.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms and conditions of the GNU General Public License,
  11  * version 2, as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  20  * Place - Suite 330, Boston, MA 02111-1307 USA.
  21  */
  22
  23 /*
  24  * Derived from:
  25  *      VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai.
  26  *      This implementation is herby placed in the public domain.
  27  *      The authors offers no warranty. Use at your own risk.
  28  *      Last modified: 17 APR 08, 1700 PDT
  29  */
  30
  31 #include <asm/unaligned.h>
  32 #include <linux/init.h>
  33 #include <linux/types.h>
  34 #include <linux/crypto.h>
  35 #include <linux/module.h>
  36 #include <linux/scatterlist.h>
  37 #include <asm/byteorder.h>
  38 #include <crypto/scatterwalk.h>
  39 #include <crypto/internal/hash.h>
  40
  41 /*
  42  * User definable settings.
  43  */
  44 #define VMAC_TAG_LEN    64
  45 #define VMAC_KEY_SIZE   128/* Must be 128, 192 or 256                   */
  46 #define VMAC_KEY_LEN    (VMAC_KEY_SIZE/8)
  47 #define VMAC_NHBYTES    128/* Must 2^i for any 3 < i < 13 Standard = 128*/
  48
  49 /* per-transform (per-key) context */
  50 struct vmac_tfm_ctx {
  51         struct crypto_cipher *cipher;
  52         u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)];
  53         u64 polykey[2*VMAC_TAG_LEN/64];
  54         u64 l3key[2*VMAC_TAG_LEN/64];
  55 };
  56
  57 /* per-request context */
  58 struct vmac_desc_ctx {
  59         union {
  60                 u8 partial[VMAC_NHBYTES];       /* partial block */
  61                 __le64 partial_words[VMAC_NHBYTES / 8];
  62         };
  63         unsigned int partial_size;      /* size of the partial block */
  64         bool first_block_processed;
  65         u64 polytmp[2*VMAC_TAG_LEN/64]; /* running total of L2-hash */
  66 };
  67
  68 /*
  69  * Constants and masks
  70  */
  71 #define UINT64_C(x) x##ULL
  72 static const u64 p64   = UINT64_C(0xfffffffffffffeff);  /* 2^64 - 257 prime  */
  73 static const u64 m62   = UINT64_C(0x3fffffffffffffff);  /* 62-bit mask       */
  74 static const u64 m63   = UINT64_C(0x7fffffffffffffff);  /* 63-bit mask       */
  75 static const u64 m64   = UINT64_C(0xffffffffffffffff);  /* 64-bit mask       */
  76 static const u64 mpoly = UINT64_C(0x1fffffff1fffffff);  /* Poly key mask     */
  77
  78 #define pe64_to_cpup le64_to_cpup               /* Prefer little endian */
  79
  80 #ifdef __LITTLE_ENDIAN
  81 #define INDEX_HIGH 1
  82 #define INDEX_LOW 0
  83 #else
  84 #define INDEX_HIGH 0
  85 #define INDEX_LOW 1
  86 #endif
  87
  88 /*
  89  * The following routines are used in this implementation. They are
  90  * written via macros to simulate zero-overhead call-by-reference.
  91  *
  92  * MUL64: 64x64->128-bit multiplication
  93  * PMUL64: assumes top bits cleared on inputs
  94  * ADD128: 128x128->128-bit addition
  95  */
  96
  97 #define ADD128(rh, rl, ih, il)                                          \
  98         do {                                                            \
  99                 u64 _il = (il);                                         \
 100                 (rl) += (_il);                                          \
 101                 if ((rl) < (_il))                                       \
 102                         (rh)++;                                         \
 103                 (rh) += (ih);                                           \
 104         } while (0)
 105
 106 #define MUL32(i1, i2)   ((u64)(u32)(i1)*(u32)(i2))
 107
 108 #define PMUL64(rh, rl, i1, i2)  /* Assumes m doesn't overflow */        \
 109         do {                                                            \
 110                 u64 _i1 = (i1), _i2 = (i2);                             \
 111                 u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2);      \
 112                 rh = MUL32(_i1>>32, _i2>>32);                           \
 113                 rl = MUL32(_i1, _i2);                                   \
 114                 ADD128(rh, rl, (m >> 32), (m << 32));                   \
 115         } while (0)
 116
 117 #define MUL64(rh, rl, i1, i2)                                           \
 118         do {                                                            \
 119                 u64 _i1 = (i1), _i2 = (i2);                             \
 120                 u64 m1 = MUL32(_i1, _i2>>32);                           \
 121                 u64 m2 = MUL32(_i1>>32, _i2);                           \
 122                 rh = MUL32(_i1>>32, _i2>>32);                           \
 123                 rl = MUL32(_i1, _i2);                                   \
 124                 ADD128(rh, rl, (m1 >> 32), (m1 << 32));                 \
 125                 ADD128(rh, rl, (m2 >> 32), (m2 << 32));                 \
 126         } while (0)
 127
 128 /*
 129  * For highest performance the L1 NH and L2 polynomial hashes should be
 130  * carefully implemented to take advantage of one's target architecture.
 131  * Here these two hash functions are defined multiple time; once for
 132  * 64-bit architectures, once for 32-bit SSE2 architectures, and once
 133  * for the rest (32-bit) architectures.
 134  * For each, nh_16 *must* be defined (works on multiples of 16 bytes).
 135  * Optionally, nh_vmac_nhbytes can be defined (for multiples of
 136  * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two
 137  * NH computations at once).
 138  */
 139
 140 #ifdef CONFIG_64BIT
 141
 142 #define nh_16(mp, kp, nw, rh, rl)                                       \
 143         do {                                                            \
 144                 int i; u64 th, tl;                                      \
 145                 rh = rl = 0;                                            \
 146                 for (i = 0; i < nw; i += 2) {                           \
 147                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 148                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 149                         ADD128(rh, rl, th, tl);                         \
 150                 }                                                       \
 151         } while (0)
 152
 153 #define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1)                           \
 154         do {                                                            \
 155                 int i; u64 th, tl;                                      \
 156                 rh1 = rl1 = rh = rl = 0;                                \
 157                 for (i = 0; i < nw; i += 2) {                           \
 158                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 159                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 160                         ADD128(rh, rl, th, tl);                         \
 161                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],   \
 162                                 pe64_to_cpup((mp)+i+1)+(kp)[i+3]);      \
 163                         ADD128(rh1, rl1, th, tl);                       \
 164                 }                                                       \
 165         } while (0)
 166
 167 #if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */
 168 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl)                             \
 169         do {                                                            \
 170                 int i; u64 th, tl;                                      \
 171                 rh = rl = 0;                                            \
 172                 for (i = 0; i < nw; i += 8) {                           \
 173                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 174                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 175                         ADD128(rh, rl, th, tl);                         \
 176                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
 177                                 pe64_to_cpup((mp)+i+3)+(kp)[i+3]);      \
 178                         ADD128(rh, rl, th, tl);                         \
 179                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
 180                                 pe64_to_cpup((mp)+i+5)+(kp)[i+5]);      \
 181                         ADD128(rh, rl, th, tl);                         \
 182                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
 183                                 pe64_to_cpup((mp)+i+7)+(kp)[i+7]);      \
 184                         ADD128(rh, rl, th, tl);                         \
 185                 }                                                       \
 186         } while (0)
 187
 188 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1)                 \
 189         do {                                                            \
 190                 int i; u64 th, tl;                                      \
 191                 rh1 = rl1 = rh = rl = 0;                                \
 192                 for (i = 0; i < nw; i += 8) {                           \
 193                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 194                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 195                         ADD128(rh, rl, th, tl);                         \
 196                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],   \
 197                                 pe64_to_cpup((mp)+i+1)+(kp)[i+3]);      \
 198                         ADD128(rh1, rl1, th, tl);                       \
 199                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
 200                                 pe64_to_cpup((mp)+i+3)+(kp)[i+3]);      \
 201                         ADD128(rh, rl, th, tl);                         \
 202                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4], \
 203                                 pe64_to_cpup((mp)+i+3)+(kp)[i+5]);      \
 204                         ADD128(rh1, rl1, th, tl);                       \
 205                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
 206                                 pe64_to_cpup((mp)+i+5)+(kp)[i+5]);      \
 207                         ADD128(rh, rl, th, tl);                         \
 208                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6], \
 209                                 pe64_to_cpup((mp)+i+5)+(kp)[i+7]);      \
 210                         ADD128(rh1, rl1, th, tl);                       \
 211                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
 212                                 pe64_to_cpup((mp)+i+7)+(kp)[i+7]);      \
 213                         ADD128(rh, rl, th, tl);                         \
 214                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8], \
 215                                 pe64_to_cpup((mp)+i+7)+(kp)[i+9]);      \
 216                         ADD128(rh1, rl1, th, tl);                       \
 217                 }                                                       \
 218         } while (0)
 219 #endif
 220
 221 #define poly_step(ah, al, kh, kl, mh, ml)                               \
 222         do {                                                            \
 223                 u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0;                \
 224                 /* compute ab*cd, put bd into result registers */       \
 225                 PMUL64(t3h, t3l, al, kh);                               \
 226                 PMUL64(t2h, t2l, ah, kl);                               \
 227                 PMUL64(t1h, t1l, ah, 2*kh);                             \
 228                 PMUL64(ah, al, al, kl);                                 \
 229                 /* add 2 * ac to result */                              \
 230                 ADD128(ah, al, t1h, t1l);                               \
 231                 /* add together ad + bc */                              \
 232                 ADD128(t2h, t2l, t3h, t3l);                             \
 233                 /* now (ah,al), (t2l,2*t2h) need summing */             \
 234                 /* first add the high registers, carrying into t2h */   \
 235                 ADD128(t2h, ah, z, t2l);                                \
 236                 /* double t2h and add top bit of ah */                  \
 237                 t2h = 2 * t2h + (ah >> 63);                             \
 238                 ah &= m63;                                              \
 239                 /* now add the low registers */                         \
 240                 ADD128(ah, al, mh, ml);                                 \
 241                 ADD128(ah, al, z, t2h);                                 \
 242         } while (0)
 243
 244 #else /* ! CONFIG_64BIT */
 245
 246 #ifndef nh_16
 247 #define nh_16(mp, kp, nw, rh, rl)                                       \
 248         do {                                                            \
 249                 u64 t1, t2, m1, m2, t;                                  \
 250                 int i;                                                  \
 251                 rh = rl = t = 0;                                        \
 252                 for (i = 0; i < nw; i += 2)  {                          \
 253                         t1 = pe64_to_cpup(mp+i) + kp[i];                \
 254                         t2 = pe64_to_cpup(mp+i+1) + kp[i+1];            \
 255                         m2 = MUL32(t1 >> 32, t2);                       \
 256                         m1 = MUL32(t1, t2 >> 32);                       \
 257                         ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32),       \
 258                                 MUL32(t1, t2));                         \
 259                         rh += (u64)(u32)(m1 >> 32)                      \
 260                                 + (u32)(m2 >> 32);                      \
 261                         t += (u64)(u32)m1 + (u32)m2;                    \
 262                 }                                                       \
 263                 ADD128(rh, rl, (t >> 32), (t << 32));                   \
 264         } while (0)
 265 #endif
 266
 267 static void poly_step_func(u64 *ahi, u64 *alo,
 268                         const u64 *kh, const u64 *kl,
 269                         const u64 *mh, const u64 *ml)
 270 {
 271 #define a0 (*(((u32 *)alo)+INDEX_LOW))
 272 #define a1 (*(((u32 *)alo)+INDEX_HIGH))
 273 #define a2 (*(((u32 *)ahi)+INDEX_LOW))
 274 #define a3 (*(((u32 *)ahi)+INDEX_HIGH))
 275 #define k0 (*(((u32 *)kl)+INDEX_LOW))
 276 #define k1 (*(((u32 *)kl)+INDEX_HIGH))
 277 #define k2 (*(((u32 *)kh)+INDEX_LOW))
 278 #define k3 (*(((u32 *)kh)+INDEX_HIGH))
 279
 280         u64 p, q, t;
 281         u32 t2;
 282
 283         p = MUL32(a3, k3);
 284         p += p;
 285         p += *(u64 *)mh;
 286         p += MUL32(a0, k2);
 287         p += MUL32(a1, k1);
 288         p += MUL32(a2, k0);
 289         t = (u32)(p);
 290         p >>= 32;
 291         p += MUL32(a0, k3);
 292         p += MUL32(a1, k2);
 293         p += MUL32(a2, k1);
 294         p += MUL32(a3, k0);
 295         t |= ((u64)((u32)p & 0x7fffffff)) << 32;
 296         p >>= 31;
 297         p += (u64)(((u32 *)ml)[INDEX_LOW]);
 298         p += MUL32(a0, k0);
 299         q =  MUL32(a1, k3);
 300         q += MUL32(a2, k2);
 301         q += MUL32(a3, k1);
 302         q += q;
 303         p += q;
 304         t2 = (u32)(p);
 305         p >>= 32;
 306         p += (u64)(((u32 *)ml)[INDEX_HIGH]);
 307         p += MUL32(a0, k1);
 308         p += MUL32(a1, k0);
 309         q =  MUL32(a2, k3);
 310         q += MUL32(a3, k2);
 311         q += q;
 312         p += q;
 313         *(u64 *)(alo) = (p << 32) | t2;
 314         p >>= 32;
 315         *(u64 *)(ahi) = p + t;
 316
 317 #undef a0
 318 #undef a1
 319 #undef a2
 320 #undef a3
 321 #undef k0
 322 #undef k1
 323 #undef k2
 324 #undef k3
 325 }
 326
 327 #define poly_step(ah, al, kh, kl, mh, ml)                               \
 328         poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml))
 329
 330 #endif  /* end of specialized NH and poly definitions */
 331
 332 /* At least nh_16 is defined. Defined others as needed here */
 333 #ifndef nh_16_2
 334 #define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2)                           \
 335         do {                                                            \
 336                 nh_16(mp, kp, nw, rh, rl);                              \
 337                 nh_16(mp, ((kp)+2), nw, rh2, rl2);                      \
 338         } while (0)
 339 #endif
 340 #ifndef nh_vmac_nhbytes
 341 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl)                             \
 342         nh_16(mp, kp, nw, rh, rl)
 343 #endif
 344 #ifndef nh_vmac_nhbytes_2
 345 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2)                 \
 346         do {                                                            \
 347                 nh_vmac_nhbytes(mp, kp, nw, rh, rl);                    \
 348                 nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2);            \
 349         } while (0)
 350 #endif
 351
 352 static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len)
 353 {
 354         u64 rh, rl, t, z = 0;
 355
 356         /* fully reduce (p1,p2)+(len,0) mod p127 */
 357         t = p1 >> 63;
 358         p1 &= m63;
 359         ADD128(p1, p2, len, t);
 360         /* At this point, (p1,p2) is at most 2^127+(len<<64) */
 361         t = (p1 > m63) + ((p1 == m63) && (p2 == m64));
 362         ADD128(p1, p2, z, t);
 363         p1 &= m63;
 364
 365         /* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */
 366         t = p1 + (p2 >> 32);
 367         t += (t >> 32);
 368         t += (u32)t > 0xfffffffeu;
 369         p1 += (t >> 32);
 370         p2 += (p1 << 32);
 371
 372         /* compute (p1+k1)%p64 and (p2+k2)%p64 */
 373         p1 += k1;
 374         p1 += (0 - (p1 < k1)) & 257;
 375         p2 += k2;
 376         p2 += (0 - (p2 < k2)) & 257;
 377
 378         /* compute (p1+k1)*(p2+k2)%p64 */
 379         MUL64(rh, rl, p1, p2);
 380         t = rh >> 56;
 381         ADD128(t, rl, z, rh);
 382         rh <<= 8;
 383         ADD128(t, rl, z, rh);
 384         t += t << 8;
 385         rl += t;
 386         rl += (0 - (rl < t)) & 257;
 387         rl += (0 - (rl > p64-1)) & 257;
 388         return rl;
 389 }
 390
 391 /* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */
 392 static void vhash_blocks(const struct vmac_tfm_ctx *tctx,
 393                          struct vmac_desc_ctx *dctx,
 394                          const __le64 *mptr, unsigned int blocks)
 395 {
 396         const u64 *kptr = tctx->nhkey;
 397         const u64 pkh = tctx->polykey[0];
 398         const u64 pkl = tctx->polykey[1];
 399         u64 ch = dctx->polytmp[0];
 400         u64 cl = dctx->polytmp[1];
 401         u64 rh, rl;
 402
 403         if (!dctx->first_block_processed) {
 404                 dctx->first_block_processed = true;
 405                 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
 406                 rh &= m62;
 407                 ADD128(ch, cl, rh, rl);
 408                 mptr += (VMAC_NHBYTES/sizeof(u64));
 409                 blocks--;
 410         }
 411
 412         while (blocks--) {
 413                 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
 414                 rh &= m62;
 415                 poly_step(ch, cl, pkh, pkl, rh, rl);
 416                 mptr += (VMAC_NHBYTES/sizeof(u64));
 417         }
 418
 419         dctx->polytmp[0] = ch;
 420         dctx->polytmp[1] = cl;
 421 }
 422
 423 static int vmac_setkey(struct crypto_shash *tfm,
 424                        const u8 *key, unsigned int keylen)
 425 {
 426         struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm);
 427         __be64 out[2];
 428         u8 in[16] = { 0 };
 429         unsigned int i;
 430         int err;
 431
 432         if (keylen != VMAC_KEY_LEN) {
 433                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 434                 return -EINVAL;
 435         }
 436
 437         err = crypto_cipher_setkey(tctx->cipher, key, keylen);
 438         if (err)
 439                 return err;
 440
 441         /* Fill nh key */
 442         in[0] = 0x80;
 443         for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) {
 444                 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 445                 tctx->nhkey[i] = be64_to_cpu(out[0]);
 446                 tctx->nhkey[i+1] = be64_to_cpu(out[1]);
 447                 in[15]++;
 448         }
 449
 450         /* Fill poly key */
 451         in[0] = 0xC0;
 452         in[15] = 0;
 453         for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) {
 454                 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 455                 tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly;
 456                 tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly;
 457                 in[15]++;
 458         }
 459
 460         /* Fill ip key */
 461         in[0] = 0xE0;
 462         in[15] = 0;
 463         for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) {
 464                 do {
 465                         crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 466                         tctx->l3key[i] = be64_to_cpu(out[0]);
 467                         tctx->l3key[i+1] = be64_to_cpu(out[1]);
 468                         in[15]++;
 469                 } while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64);
 470         }
 471
 472         return 0;
 473 }
 474
 475 static int vmac_init(struct shash_desc *desc)
 476 {
 477         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 478         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 479
 480         dctx->partial_size = 0;
 481         dctx->first_block_processed = false;
 482         memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp));
 483         return 0;
 484 }
 485
 486 static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len)
 487 {
 488         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 489         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 490         unsigned int n;
 491
 492         if (dctx->partial_size) {
 493                 n = min(len, VMAC_NHBYTES - dctx->partial_size);
 494                 memcpy(&dctx->partial[dctx->partial_size], p, n);
 495                 dctx->partial_size += n;
 496                 p += n;
 497                 len -= n;
 498                 if (dctx->partial_size == VMAC_NHBYTES) {
 499                         vhash_blocks(tctx, dctx, dctx->partial_words, 1);
 500                         dctx->partial_size = 0;
 501                 }
 502         }
 503
 504         if (len >= VMAC_NHBYTES) {
 505                 n = round_down(len, VMAC_NHBYTES);
 506                 /* TODO: 'p' may be misaligned here */
 507                 vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES);
 508                 p += n;
 509                 len -= n;
 510         }
 511
 512         if (len) {
 513                 memcpy(dctx->partial, p, len);
 514                 dctx->partial_size = len;
 515         }
 516
 517         return 0;
 518 }
 519
 520 static u64 vhash_final(const struct vmac_tfm_ctx *tctx,
 521                        struct vmac_desc_ctx *dctx)
 522 {
 523         unsigned int partial = dctx->partial_size;
 524         u64 ch = dctx->polytmp[0];
 525         u64 cl = dctx->polytmp[1];
 526
 527         /* L1 and L2-hash the final block if needed */
 528         if (partial) {
 529                 /* Zero-pad to next 128-bit boundary */
 530                 unsigned int n = round_up(partial, 16);
 531                 u64 rh, rl;
 532
 533                 memset(&dctx->partial[partial], 0, n - partial);
 534                 nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl);
 535                 rh &= m62;
 536                 if (dctx->first_block_processed)
 537                         poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1],
 538                                   rh, rl);
 539                 else
 540                         ADD128(ch, cl, rh, rl);
 541         }
 542
 543         /* L3-hash the 128-bit output of L2-hash */
 544         return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8);
 545 }
 546
 547 static int vmac_final(struct shash_desc *desc, u8 *out)
 548 {
 549         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 550         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 551         static const u8 nonce[16] = {}; /* TODO: this is insecure */
 552         union {
 553                 u8 bytes[16];
 554                 __be64 pads[2];
 555         } block;
 556         int index;
 557         u64 hash, pad;
 558
 559         /* Finish calculating the VHASH of the message */
 560         hash = vhash_final(tctx, dctx);
 561
 562         /* Generate pseudorandom pad by encrypting the nonce */
 563         memcpy(&block, nonce, 16);
 564         index = block.bytes[15] & 1;
 565         block.bytes[15] &= ~1;
 566         crypto_cipher_encrypt_one(tctx->cipher, block.bytes, block.bytes);
 567         pad = be64_to_cpu(block.pads[index]);
 568
 569         /* The VMAC is the sum of VHASH and the pseudorandom pad */
 570         put_unaligned_le64(hash + pad, out);
 571         return 0;
 572 }
 573
 574 static int vmac_init_tfm(struct crypto_tfm *tfm)
 575 {
 576         struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
 577         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 578         struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
 579         struct crypto_cipher *cipher;
 580
 581         cipher = crypto_spawn_cipher(spawn);
 582         if (IS_ERR(cipher))
 583                 return PTR_ERR(cipher);
 584
 585         tctx->cipher = cipher;
 586         return 0;
 587 }
 588
 589 static void vmac_exit_tfm(struct crypto_tfm *tfm)
 590 {
 591         struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
 592
 593         crypto_free_cipher(tctx->cipher);
 594 }
 595
 596 static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 597 {
 598         struct shash_instance *inst;
 599         struct crypto_alg *alg;
 600         int err;
 601
 602         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
 603         if (err)
 604                 return err;
 605
 606         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
 607                         CRYPTO_ALG_TYPE_MASK);
 608         if (IS_ERR(alg))
 609                 return PTR_ERR(alg);
 610
 611         err = -EINVAL;
 612         if (alg->cra_blocksize != 16)
 613                 goto out_put_alg;
 614
 615         inst = shash_alloc_instance("vmac", alg);
 616         err = PTR_ERR(inst);
 617         if (IS_ERR(inst))
 618                 goto out_put_alg;
 619
 620         err = crypto_init_spawn(shash_instance_ctx(inst), alg,
 621                         shash_crypto_instance(inst),
 622                         CRYPTO_ALG_TYPE_MASK);
 623         if (err)
 624                 goto out_free_inst;
 625
 626         inst->alg.base.cra_priority = alg->cra_priority;
 627         inst->alg.base.cra_blocksize = alg->cra_blocksize;
 628         inst->alg.base.cra_alignmask = alg->cra_alignmask;
 629
 630         inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx);
 631         inst->alg.base.cra_init = vmac_init_tfm;
 632         inst->alg.base.cra_exit = vmac_exit_tfm;
 633
 634         inst->alg.descsize = sizeof(struct vmac_desc_ctx);
 635         inst->alg.digestsize = VMAC_TAG_LEN / 8;
 636         inst->alg.init = vmac_init;
 637         inst->alg.update = vmac_update;
 638         inst->alg.final = vmac_final;
 639         inst->alg.setkey = vmac_setkey;
 640
 641         err = shash_register_instance(tmpl, inst);
 642         if (err) {
 643 out_free_inst:
 644                 shash_free_instance(shash_crypto_instance(inst));
 645         }
 646
 647 out_put_alg:
 648         crypto_mod_put(alg);
 649         return err;
 650 }
 651
 652 static struct crypto_template vmac_tmpl = {
 653         .name = "vmac",
 654         .create = vmac_create,
 655         .free = shash_free_instance,
 656         .module = THIS_MODULE,
 657 };
 658
 659 static int __init vmac_module_init(void)
 660 {
 661         return crypto_register_template(&vmac_tmpl);
 662 }
 663
 664 static void __exit vmac_module_exit(void)
 665 {
 666         crypto_unregister_template(&vmac_tmpl);
 667 }
 668
 669 module_init(vmac_module_init);
 670 module_exit(vmac_module_exit);
 671
 672 MODULE_LICENSE("GPL");
 673 MODULE_DESCRIPTION("VMAC hash algorithm");
 674 MODULE_ALIAS_CRYPTO("vmac");