linux/crypto/vmac.c
<<
>>
Prefs
   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/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 */
  52struct 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 */
  60struct 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
  79static const u64 p64   = UINT64_C(0xfffffffffffffeff);  /* 2^64 - 257 prime  */
  80static const u64 m62   = UINT64_C(0x3fffffffffffffff);  /* 62-bit mask       */
  81static const u64 m63   = UINT64_C(0x7fffffffffffffff);  /* 63-bit mask       */
  82static const u64 m64   = UINT64_C(0xffffffffffffffff);  /* 64-bit mask       */
  83static 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
 274static 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
 359static 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 */
 399static 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
 430static 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
 480static 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
 492static 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
 535static 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
 562static 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
 597static 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
 612static 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
 619static 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        inst->alg.base.cra_alignmask = alg->cra_alignmask;
 653
 654        inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx);
 655        inst->alg.base.cra_init = vmac_init_tfm;
 656        inst->alg.base.cra_exit = vmac_exit_tfm;
 657
 658        inst->alg.descsize = sizeof(struct vmac_desc_ctx);
 659        inst->alg.digestsize = VMAC_TAG_LEN / 8;
 660        inst->alg.init = vmac_init;
 661        inst->alg.update = vmac_update;
 662        inst->alg.final = vmac_final;
 663        inst->alg.setkey = vmac_setkey;
 664
 665        inst->free = shash_free_singlespawn_instance;
 666
 667        err = shash_register_instance(tmpl, inst);
 668        if (err) {
 669err_free_inst:
 670                shash_free_singlespawn_instance(inst);
 671        }
 672        return err;
 673}
 674
 675static struct crypto_template vmac64_tmpl = {
 676        .name = "vmac64",
 677        .create = vmac_create,
 678        .module = THIS_MODULE,
 679};
 680
 681static int __init vmac_module_init(void)
 682{
 683        return crypto_register_template(&vmac64_tmpl);
 684}
 685
 686static void __exit vmac_module_exit(void)
 687{
 688        crypto_unregister_template(&vmac64_tmpl);
 689}
 690
 691subsys_initcall(vmac_module_init);
 692module_exit(vmac_module_exit);
 693
 694MODULE_LICENSE("GPL");
 695MODULE_DESCRIPTION("VMAC hash algorithm");
 696MODULE_ALIAS_CRYPTO("vmac64");
 697MODULE_IMPORT_NS(CRYPTO_INTERNAL);
 698
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.