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 <linux/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/cipher.h>
  40 #include <crypto/internal/hash.h>
  41
  42 /*
  43  * User definable settings.
  44  */
  45 #define VMAC_TAG_LEN    64
  46 #define VMAC_KEY_SIZE   128/* Must be 128, 192 or 256                   */
  47 #define VMAC_KEY_LEN    (VMAC_KEY_SIZE/8)
  48 #define VMAC_NHBYTES    128/* Must 2^i for any 3 < i < 13 Standard = 128*/
  49 #define VMAC_NONCEBYTES 16
  50
  51 /* per-transform (per-key) context */
  52 struct vmac_tfm_ctx {
  53         struct crypto_cipher *cipher;
  54         u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)];
  55         u64 polykey[2*VMAC_TAG_LEN/64];
  56         u64 l3key[2*VMAC_TAG_LEN/64];
  57 };
  58
  59 /* per-request context */
  60 struct vmac_desc_ctx {
  61         union {
  62                 u8 partial[VMAC_NHBYTES];       /* partial block */
  63                 __le64 partial_words[VMAC_NHBYTES / 8];
  64         };
  65         unsigned int partial_size;      /* size of the partial block */
  66         bool first_block_processed;
  67         u64 polytmp[2*VMAC_TAG_LEN/64]; /* running total of L2-hash */
  68         union {
  69                 u8 bytes[VMAC_NONCEBYTES];
  70                 __be64 pads[VMAC_NONCEBYTES / 8];
  71         } nonce;
  72         unsigned int nonce_size; /* nonce bytes filled so far */
  73 };
  74
  75 /*
  76  * Constants and masks
  77  */
  78 #define UINT64_C(x) x##ULL
  79 static const u64 p64   = UINT64_C(0xfffffffffffffeff);  /* 2^64 - 257 prime  */
  80 static const u64 m62   = UINT64_C(0x3fffffffffffffff);  /* 62-bit mask       */
  81 static const u64 m63   = UINT64_C(0x7fffffffffffffff);  /* 63-bit mask       */
  82 static const u64 m64   = UINT64_C(0xffffffffffffffff);  /* 64-bit mask       */
  83 static const u64 mpoly = UINT64_C(0x1fffffff1fffffff);  /* Poly key mask     */
  84
  85 #define pe64_to_cpup le64_to_cpup               /* Prefer little endian */
  86
  87 #ifdef __LITTLE_ENDIAN
  88 #define INDEX_HIGH 1
  89 #define INDEX_LOW 0
  90 #else
  91 #define INDEX_HIGH 0
  92 #define INDEX_LOW 1
  93 #endif
  94
  95 /*
  96  * The following routines are used in this implementation. They are
  97  * written via macros to simulate zero-overhead call-by-reference.
  98  *
  99  * MUL64: 64x64->128-bit multiplication
 100  * PMUL64: assumes top bits cleared on inputs
 101  * ADD128: 128x128->128-bit addition
 102  */
 103
 104 #define ADD128(rh, rl, ih, il)                                          \
 105         do {                                                            \
 106                 u64 _il = (il);                                         \
 107                 (rl) += (_il);                                          \
 108                 if ((rl) < (_il))                                       \
 109                         (rh)++;                                         \
 110                 (rh) += (ih);                                           \
 111         } while (0)
 112
 113 #define MUL32(i1, i2)   ((u64)(u32)(i1)*(u32)(i2))
 114
 115 #define PMUL64(rh, rl, i1, i2)  /* Assumes m doesn't overflow */        \
 116         do {                                                            \
 117                 u64 _i1 = (i1), _i2 = (i2);                             \
 118                 u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2);      \
 119                 rh = MUL32(_i1>>32, _i2>>32);                           \
 120                 rl = MUL32(_i1, _i2);                                   \
 121                 ADD128(rh, rl, (m >> 32), (m << 32));                   \
 122         } while (0)
 123
 124 #define MUL64(rh, rl, i1, i2)                                           \
 125         do {                                                            \
 126                 u64 _i1 = (i1), _i2 = (i2);                             \
 127                 u64 m1 = MUL32(_i1, _i2>>32);                           \
 128                 u64 m2 = MUL32(_i1>>32, _i2);                           \
 129                 rh = MUL32(_i1>>32, _i2>>32);                           \
 130                 rl = MUL32(_i1, _i2);                                   \
 131                 ADD128(rh, rl, (m1 >> 32), (m1 << 32));                 \
 132                 ADD128(rh, rl, (m2 >> 32), (m2 << 32));                 \
 133         } while (0)
 134
 135 /*
 136  * For highest performance the L1 NH and L2 polynomial hashes should be
 137  * carefully implemented to take advantage of one's target architecture.
 138  * Here these two hash functions are defined multiple time; once for
 139  * 64-bit architectures, once for 32-bit SSE2 architectures, and once
 140  * for the rest (32-bit) architectures.
 141  * For each, nh_16 *must* be defined (works on multiples of 16 bytes).
 142  * Optionally, nh_vmac_nhbytes can be defined (for multiples of
 143  * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two
 144  * NH computations at once).
 145  */
 146
 147 #ifdef CONFIG_64BIT
 148
 149 #define nh_16(mp, kp, nw, rh, rl)                                       \
 150         do {                                                            \
 151                 int i; u64 th, tl;                                      \
 152                 rh = rl = 0;                                            \
 153                 for (i = 0; i < nw; i += 2) {                           \
 154                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 155                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 156                         ADD128(rh, rl, th, tl);                         \
 157                 }                                                       \
 158         } while (0)
 159
 160 #define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1)                           \
 161         do {                                                            \
 162                 int i; u64 th, tl;                                      \
 163                 rh1 = rl1 = rh = rl = 0;                                \
 164                 for (i = 0; i < nw; i += 2) {                           \
 165                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 166                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 167                         ADD128(rh, rl, th, tl);                         \
 168                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],   \
 169                                 pe64_to_cpup((mp)+i+1)+(kp)[i+3]);      \
 170                         ADD128(rh1, rl1, th, tl);                       \
 171                 }                                                       \
 172         } while (0)
 173
 174 #if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */
 175 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl)                             \
 176         do {                                                            \
 177                 int i; u64 th, tl;                                      \
 178                 rh = rl = 0;                                            \
 179                 for (i = 0; i < nw; i += 8) {                           \
 180                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 181                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 182                         ADD128(rh, rl, th, tl);                         \
 183                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
 184                                 pe64_to_cpup((mp)+i+3)+(kp)[i+3]);      \
 185                         ADD128(rh, rl, th, tl);                         \
 186                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
 187                                 pe64_to_cpup((mp)+i+5)+(kp)[i+5]);      \
 188                         ADD128(rh, rl, th, tl);                         \
 189                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
 190                                 pe64_to_cpup((mp)+i+7)+(kp)[i+7]);      \
 191                         ADD128(rh, rl, th, tl);                         \
 192                 }                                                       \
 193         } while (0)
 194
 195 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1)                 \
 196         do {                                                            \
 197                 int i; u64 th, tl;                                      \
 198                 rh1 = rl1 = rh = rl = 0;                                \
 199                 for (i = 0; i < nw; i += 8) {                           \
 200                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],     \
 201                                 pe64_to_cpup((mp)+i+1)+(kp)[i+1]);      \
 202                         ADD128(rh, rl, th, tl);                         \
 203                         MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],   \
 204                                 pe64_to_cpup((mp)+i+1)+(kp)[i+3]);      \
 205                         ADD128(rh1, rl1, th, tl);                       \
 206                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2], \
 207                                 pe64_to_cpup((mp)+i+3)+(kp)[i+3]);      \
 208                         ADD128(rh, rl, th, tl);                         \
 209                         MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4], \
 210                                 pe64_to_cpup((mp)+i+3)+(kp)[i+5]);      \
 211                         ADD128(rh1, rl1, th, tl);                       \
 212                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4], \
 213                                 pe64_to_cpup((mp)+i+5)+(kp)[i+5]);      \
 214                         ADD128(rh, rl, th, tl);                         \
 215                         MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6], \
 216                                 pe64_to_cpup((mp)+i+5)+(kp)[i+7]);      \
 217                         ADD128(rh1, rl1, th, tl);                       \
 218                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6], \
 219                                 pe64_to_cpup((mp)+i+7)+(kp)[i+7]);      \
 220                         ADD128(rh, rl, th, tl);                         \
 221                         MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8], \
 222                                 pe64_to_cpup((mp)+i+7)+(kp)[i+9]);      \
 223                         ADD128(rh1, rl1, th, tl);                       \
 224                 }                                                       \
 225         } while (0)
 226 #endif
 227
 228 #define poly_step(ah, al, kh, kl, mh, ml)                               \
 229         do {                                                            \
 230                 u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0;                \
 231                 /* compute ab*cd, put bd into result registers */       \
 232                 PMUL64(t3h, t3l, al, kh);                               \
 233                 PMUL64(t2h, t2l, ah, kl);                               \
 234                 PMUL64(t1h, t1l, ah, 2*kh);                             \
 235                 PMUL64(ah, al, al, kl);                                 \
 236                 /* add 2 * ac to result */                              \
 237                 ADD128(ah, al, t1h, t1l);                               \
 238                 /* add together ad + bc */                              \
 239                 ADD128(t2h, t2l, t3h, t3l);                             \
 240                 /* now (ah,al), (t2l,2*t2h) need summing */             \
 241                 /* first add the high registers, carrying into t2h */   \
 242                 ADD128(t2h, ah, z, t2l);                                \
 243                 /* double t2h and add top bit of ah */                  \
 244                 t2h = 2 * t2h + (ah >> 63);                             \
 245                 ah &= m63;                                              \
 246                 /* now add the low registers */                         \
 247                 ADD128(ah, al, mh, ml);                                 \
 248                 ADD128(ah, al, z, t2h);                                 \
 249         } while (0)
 250
 251 #else /* ! CONFIG_64BIT */
 252
 253 #ifndef nh_16
 254 #define nh_16(mp, kp, nw, rh, rl)                                       \
 255         do {                                                            \
 256                 u64 t1, t2, m1, m2, t;                                  \
 257                 int i;                                                  \
 258                 rh = rl = t = 0;                                        \
 259                 for (i = 0; i < nw; i += 2)  {                          \
 260                         t1 = pe64_to_cpup(mp+i) + kp[i];                \
 261                         t2 = pe64_to_cpup(mp+i+1) + kp[i+1];            \
 262                         m2 = MUL32(t1 >> 32, t2);                       \
 263                         m1 = MUL32(t1, t2 >> 32);                       \
 264                         ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32),       \
 265                                 MUL32(t1, t2));                         \
 266                         rh += (u64)(u32)(m1 >> 32)                      \
 267                                 + (u32)(m2 >> 32);                      \
 268                         t += (u64)(u32)m1 + (u32)m2;                    \
 269                 }                                                       \
 270                 ADD128(rh, rl, (t >> 32), (t << 32));                   \
 271         } while (0)
 272 #endif
 273
 274 static void poly_step_func(u64 *ahi, u64 *alo,
 275                         const u64 *kh, const u64 *kl,
 276                         const u64 *mh, const u64 *ml)
 277 {
 278 #define a0 (*(((u32 *)alo)+INDEX_LOW))
 279 #define a1 (*(((u32 *)alo)+INDEX_HIGH))
 280 #define a2 (*(((u32 *)ahi)+INDEX_LOW))
 281 #define a3 (*(((u32 *)ahi)+INDEX_HIGH))
 282 #define k0 (*(((u32 *)kl)+INDEX_LOW))
 283 #define k1 (*(((u32 *)kl)+INDEX_HIGH))
 284 #define k2 (*(((u32 *)kh)+INDEX_LOW))
 285 #define k3 (*(((u32 *)kh)+INDEX_HIGH))
 286
 287         u64 p, q, t;
 288         u32 t2;
 289
 290         p = MUL32(a3, k3);
 291         p += p;
 292         p += *(u64 *)mh;
 293         p += MUL32(a0, k2);
 294         p += MUL32(a1, k1);
 295         p += MUL32(a2, k0);
 296         t = (u32)(p);
 297         p >>= 32;
 298         p += MUL32(a0, k3);
 299         p += MUL32(a1, k2);
 300         p += MUL32(a2, k1);
 301         p += MUL32(a3, k0);
 302         t |= ((u64)((u32)p & 0x7fffffff)) << 32;
 303         p >>= 31;
 304         p += (u64)(((u32 *)ml)[INDEX_LOW]);
 305         p += MUL32(a0, k0);
 306         q =  MUL32(a1, k3);
 307         q += MUL32(a2, k2);
 308         q += MUL32(a3, k1);
 309         q += q;
 310         p += q;
 311         t2 = (u32)(p);
 312         p >>= 32;
 313         p += (u64)(((u32 *)ml)[INDEX_HIGH]);
 314         p += MUL32(a0, k1);
 315         p += MUL32(a1, k0);
 316         q =  MUL32(a2, k3);
 317         q += MUL32(a3, k2);
 318         q += q;
 319         p += q;
 320         *(u64 *)(alo) = (p << 32) | t2;
 321         p >>= 32;
 322         *(u64 *)(ahi) = p + t;
 323
 324 #undef a0
 325 #undef a1
 326 #undef a2
 327 #undef a3
 328 #undef k0
 329 #undef k1
 330 #undef k2
 331 #undef k3
 332 }
 333
 334 #define poly_step(ah, al, kh, kl, mh, ml)                               \
 335         poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml))
 336
 337 #endif  /* end of specialized NH and poly definitions */
 338
 339 /* At least nh_16 is defined. Defined others as needed here */
 340 #ifndef nh_16_2
 341 #define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2)                           \
 342         do {                                                            \
 343                 nh_16(mp, kp, nw, rh, rl);                              \
 344                 nh_16(mp, ((kp)+2), nw, rh2, rl2);                      \
 345         } while (0)
 346 #endif
 347 #ifndef nh_vmac_nhbytes
 348 #define nh_vmac_nhbytes(mp, kp, nw, rh, rl)                             \
 349         nh_16(mp, kp, nw, rh, rl)
 350 #endif
 351 #ifndef nh_vmac_nhbytes_2
 352 #define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2)                 \
 353         do {                                                            \
 354                 nh_vmac_nhbytes(mp, kp, nw, rh, rl);                    \
 355                 nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2);            \
 356         } while (0)
 357 #endif
 358
 359 static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len)
 360 {
 361         u64 rh, rl, t, z = 0;
 362
 363         /* fully reduce (p1,p2)+(len,0) mod p127 */
 364         t = p1 >> 63;
 365         p1 &= m63;
 366         ADD128(p1, p2, len, t);
 367         /* At this point, (p1,p2) is at most 2^127+(len<<64) */
 368         t = (p1 > m63) + ((p1 == m63) && (p2 == m64));
 369         ADD128(p1, p2, z, t);
 370         p1 &= m63;
 371
 372         /* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */
 373         t = p1 + (p2 >> 32);
 374         t += (t >> 32);
 375         t += (u32)t > 0xfffffffeu;
 376         p1 += (t >> 32);
 377         p2 += (p1 << 32);
 378
 379         /* compute (p1+k1)%p64 and (p2+k2)%p64 */
 380         p1 += k1;
 381         p1 += (0 - (p1 < k1)) & 257;
 382         p2 += k2;
 383         p2 += (0 - (p2 < k2)) & 257;
 384
 385         /* compute (p1+k1)*(p2+k2)%p64 */
 386         MUL64(rh, rl, p1, p2);
 387         t = rh >> 56;
 388         ADD128(t, rl, z, rh);
 389         rh <<= 8;
 390         ADD128(t, rl, z, rh);
 391         t += t << 8;
 392         rl += t;
 393         rl += (0 - (rl < t)) & 257;
 394         rl += (0 - (rl > p64-1)) & 257;
 395         return rl;
 396 }
 397
 398 /* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */
 399 static void vhash_blocks(const struct vmac_tfm_ctx *tctx,
 400                          struct vmac_desc_ctx *dctx,
 401                          const __le64 *mptr, unsigned int blocks)
 402 {
 403         const u64 *kptr = tctx->nhkey;
 404         const u64 pkh = tctx->polykey[0];
 405         const u64 pkl = tctx->polykey[1];
 406         u64 ch = dctx->polytmp[0];
 407         u64 cl = dctx->polytmp[1];
 408         u64 rh, rl;
 409
 410         if (!dctx->first_block_processed) {
 411                 dctx->first_block_processed = true;
 412                 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
 413                 rh &= m62;
 414                 ADD128(ch, cl, rh, rl);
 415                 mptr += (VMAC_NHBYTES/sizeof(u64));
 416                 blocks--;
 417         }
 418
 419         while (blocks--) {
 420                 nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
 421                 rh &= m62;
 422                 poly_step(ch, cl, pkh, pkl, rh, rl);
 423                 mptr += (VMAC_NHBYTES/sizeof(u64));
 424         }
 425
 426         dctx->polytmp[0] = ch;
 427         dctx->polytmp[1] = cl;
 428 }
 429
 430 static int vmac_setkey(struct crypto_shash *tfm,
 431                        const u8 *key, unsigned int keylen)
 432 {
 433         struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm);
 434         __be64 out[2];
 435         u8 in[16] = { 0 };
 436         unsigned int i;
 437         int err;
 438
 439         if (keylen != VMAC_KEY_LEN)
 440                 return -EINVAL;
 441
 442         err = crypto_cipher_setkey(tctx->cipher, key, keylen);
 443         if (err)
 444                 return err;
 445
 446         /* Fill nh key */
 447         in[0] = 0x80;
 448         for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) {
 449                 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 450                 tctx->nhkey[i] = be64_to_cpu(out[0]);
 451                 tctx->nhkey[i+1] = be64_to_cpu(out[1]);
 452                 in[15]++;
 453         }
 454
 455         /* Fill poly key */
 456         in[0] = 0xC0;
 457         in[15] = 0;
 458         for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) {
 459                 crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 460                 tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly;
 461                 tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly;
 462                 in[15]++;
 463         }
 464
 465         /* Fill ip key */
 466         in[0] = 0xE0;
 467         in[15] = 0;
 468         for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) {
 469                 do {
 470                         crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
 471                         tctx->l3key[i] = be64_to_cpu(out[0]);
 472                         tctx->l3key[i+1] = be64_to_cpu(out[1]);
 473                         in[15]++;
 474                 } while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64);
 475         }
 476
 477         return 0;
 478 }
 479
 480 static int vmac_init(struct shash_desc *desc)
 481 {
 482         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 483         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 484
 485         dctx->partial_size = 0;
 486         dctx->first_block_processed = false;
 487         memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp));
 488         dctx->nonce_size = 0;
 489         return 0;
 490 }
 491
 492 static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len)
 493 {
 494         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 495         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 496         unsigned int n;
 497
 498         /* Nonce is passed as first VMAC_NONCEBYTES bytes of data */
 499         if (dctx->nonce_size < VMAC_NONCEBYTES) {
 500                 n = min(len, VMAC_NONCEBYTES - dctx->nonce_size);
 501                 memcpy(&dctx->nonce.bytes[dctx->nonce_size], p, n);
 502                 dctx->nonce_size += n;
 503                 p += n;
 504                 len -= n;
 505         }
 506
 507         if (dctx->partial_size) {
 508                 n = min(len, VMAC_NHBYTES - dctx->partial_size);
 509                 memcpy(&dctx->partial[dctx->partial_size], p, n);
 510                 dctx->partial_size += n;
 511                 p += n;
 512                 len -= n;
 513                 if (dctx->partial_size == VMAC_NHBYTES) {
 514                         vhash_blocks(tctx, dctx, dctx->partial_words, 1);
 515                         dctx->partial_size = 0;
 516                 }
 517         }
 518
 519         if (len >= VMAC_NHBYTES) {
 520                 n = round_down(len, VMAC_NHBYTES);
 521                 /* TODO: 'p' may be misaligned here */
 522                 vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES);
 523                 p += n;
 524                 len -= n;
 525         }
 526
 527         if (len) {
 528                 memcpy(dctx->partial, p, len);
 529                 dctx->partial_size = len;
 530         }
 531
 532         return 0;
 533 }
 534
 535 static u64 vhash_final(const struct vmac_tfm_ctx *tctx,
 536                        struct vmac_desc_ctx *dctx)
 537 {
 538         unsigned int partial = dctx->partial_size;
 539         u64 ch = dctx->polytmp[0];
 540         u64 cl = dctx->polytmp[1];
 541
 542         /* L1 and L2-hash the final block if needed */
 543         if (partial) {
 544                 /* Zero-pad to next 128-bit boundary */
 545                 unsigned int n = round_up(partial, 16);
 546                 u64 rh, rl;
 547
 548                 memset(&dctx->partial[partial], 0, n - partial);
 549                 nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl);
 550                 rh &= m62;
 551                 if (dctx->first_block_processed)
 552                         poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1],
 553                                   rh, rl);
 554                 else
 555                         ADD128(ch, cl, rh, rl);
 556         }
 557
 558         /* L3-hash the 128-bit output of L2-hash */
 559         return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8);
 560 }
 561
 562 static int vmac_final(struct shash_desc *desc, u8 *out)
 563 {
 564         const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
 565         struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
 566         int index;
 567         u64 hash, pad;
 568
 569         if (dctx->nonce_size != VMAC_NONCEBYTES)
 570                 return -EINVAL;
 571
 572         /*
 573          * The VMAC specification requires a nonce at least 1 bit shorter than
 574          * the block cipher's block length, so we actually only accept a 127-bit
 575          * nonce.  We define the unused bit to be the first one and require that
 576          * it be 0, so the needed prepending of a 0 bit is implicit.
 577          */
 578         if (dctx->nonce.bytes[0] & 0x80)
 579                 return -EINVAL;
 580
 581         /* Finish calculating the VHASH of the message */
 582         hash = vhash_final(tctx, dctx);
 583
 584         /* Generate pseudorandom pad by encrypting the nonce */
 585         BUILD_BUG_ON(VMAC_NONCEBYTES != 2 * (VMAC_TAG_LEN / 8));
 586         index = dctx->nonce.bytes[VMAC_NONCEBYTES - 1] & 1;
 587         dctx->nonce.bytes[VMAC_NONCEBYTES - 1] &= ~1;
 588         crypto_cipher_encrypt_one(tctx->cipher, dctx->nonce.bytes,
 589                                   dctx->nonce.bytes);
 590         pad = be64_to_cpu(dctx->nonce.pads[index]);
 591
 592         /* The VMAC is the sum of VHASH and the pseudorandom pad */
 593         put_unaligned_be64(hash + pad, out);
 594         return 0;
 595 }
 596
 597 static int vmac_init_tfm(struct crypto_tfm *tfm)
 598 {
 599         struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
 600         struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
 601         struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
 602         struct crypto_cipher *cipher;
 603
 604         cipher = crypto_spawn_cipher(spawn);
 605         if (IS_ERR(cipher))
 606                 return PTR_ERR(cipher);
 607
 608         tctx->cipher = cipher;
 609         return 0;
 610 }
 611
 612 static void vmac_exit_tfm(struct crypto_tfm *tfm)
 613 {
 614         struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
 615
 616         crypto_free_cipher(tctx->cipher);
 617 }
 618
 619 static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 620 {
 621         struct shash_instance *inst;
 622         struct crypto_cipher_spawn *spawn;
 623         struct crypto_alg *alg;
 624         u32 mask;
 625         int err;
 626
 627         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
 628         if (err)
 629                 return err;
 630
 631         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 632         if (!inst)
 633                 return -ENOMEM;
 634         spawn = shash_instance_ctx(inst);
 635
 636         err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
 637                                  crypto_attr_alg_name(tb[1]), 0, mask);
 638         if (err)
 639                 goto err_free_inst;
 640         alg = crypto_spawn_cipher_alg(spawn);
 641
 642         err = -EINVAL;
 643         if (alg->cra_blocksize != VMAC_NONCEBYTES)
 644                 goto err_free_inst;
 645
 646         err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
 647         if (err)
 648                 goto err_free_inst;
 649
 650         inst->alg.base.cra_priority = alg->cra_priority;
 651         inst->alg.base.cra_blocksize = alg->cra_blocksize;
 652
 653         inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx);
 654         inst->alg.base.cra_init = vmac_init_tfm;
 655         inst->alg.base.cra_exit = vmac_exit_tfm;
 656
 657         inst->alg.descsize = sizeof(struct vmac_desc_ctx);
 658         inst->alg.digestsize = VMAC_TAG_LEN / 8;
 659         inst->alg.init = vmac_init;
 660         inst->alg.update = vmac_update;
 661         inst->alg.final = vmac_final;
 662         inst->alg.setkey = vmac_setkey;
 663
 664         inst->free = shash_free_singlespawn_instance;
 665
 666         err = shash_register_instance(tmpl, inst);
 667         if (err) {
 668 err_free_inst:
 669                 shash_free_singlespawn_instance(inst);
 670         }
 671         return err;
 672 }
 673
 674 static struct crypto_template vmac64_tmpl = {
 675         .name = "vmac64",
 676         .create = vmac_create,
 677         .module = THIS_MODULE,
 678 };
 679
 680 static int __init vmac_module_init(void)
 681 {
 682         return crypto_register_template(&vmac64_tmpl);
 683 }
 684
 685 static void __exit vmac_module_exit(void)
 686 {
 687         crypto_unregister_template(&vmac64_tmpl);
 688 }
 689
 690 subsys_initcall(vmac_module_init);
 691 module_exit(vmac_module_exit);
 692
 693 MODULE_LICENSE("GPL");
 694 MODULE_DESCRIPTION("VMAC hash algorithm");
 695 MODULE_ALIAS_CRYPTO("vmac64");
 696 MODULE_IMPORT_NS("CRYPTO_INTERNAL");