chiark - git - mdw - catacomb/blob - symm/chacha.c

   1 /* -*-c-*-
   2  *
   3  * ChaCha stream cipher
   4  *
   5  * (c) 2015 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <stdarg.h>
  31
  32 #include <mLib/bits.h>
  33
  34 #include "arena.h"
  35 #include "chacha.h"
  36 #include "chacha-core.h"
  37 #include "gcipher.h"
  38 #include "grand.h"
  39 #include "keysz.h"
  40 #include "paranoia.h"
  41
  42 /*----- Global variables --------------------------------------------------*/
  43
  44 const octet chacha_keysz[] = { KSZ_SET, 32, 16, 10, 0 };
  45
  46 /*----- The ChaCha core function and utilities ----------------------------*/
  47
  48 /* --- @core@ --- *
  49  *
  50  * Arguments:   @unsigned r@ = number of rounds
  51  *              @const chacha_matrix src@ = input matrix
  52  *              @chacha_matrix dest@ = where to put the output
  53  *
  54  * Returns:     ---
  55  *
  56  *
  57  * Use:         Apply the ChaCha/r core function to @src@, writing the
  58  *              result to @dest@.  This consists of @r@ rounds followed by
  59  *              the feedforward step.
  60  */
  61
  62 static void core(unsigned r, const chacha_matrix src, chacha_matrix dest)
  63   { CHACHA_nR(dest, src, r); CHACHA_FFWD(dest, src); }
  64
  65 /* --- @populate@ --- *
  66  *
  67  * Arguments:   @chacha_matrix a@ = a matrix to fill in
  68  *              @const void *key@ = pointer to key material
  69  *              @size_t ksz@ = size of key
  70  *
  71  * Returns:     ---
  72  *
  73  * Use:         Fills in a ChaCha matrix from the key, setting the
  74  *              appropriate constants according to the key length.  The nonce
  75  *              and position words are left uninitialized.
  76  */
  77
  78 static void populate(chacha_matrix a, const void *key, size_t ksz)
  79 {
  80   const octet *k = key;
  81
  82   KSZ_ASSERT(chacha, ksz);
  83
  84   a[ 4] = LOAD32_L(k +  0);
  85   a[ 5] = LOAD32_L(k +  4);
  86   if (ksz == 10) {
  87     a[ 6] = LOAD16_L(k +  8);
  88     a[ 7] = 0;
  89   } else {
  90     a[ 6] = LOAD32_L(k +  8);
  91     a[ 7] = LOAD32_L(k + 12);
  92   }
  93   if (ksz <= 16) {
  94     a[ 8] = a[ 4];
  95     a[ 9] = a[ 5];
  96     a[10] = a[ 6];
  97     a[11] = a[ 7];
  98     a[ 0] = CHACHA_A128;
  99     a[ 1] = CHACHA_B128;
 100     a[ 2] = ksz == 10 ? CHACHA_C80 : CHACHA_C128;
 101     a[ 3] = CHACHA_D128;
 102   } else {
 103     a[ 8] = LOAD32_L(k + 16);
 104     a[ 9] = LOAD32_L(k + 20);
 105     a[10] = LOAD32_L(k + 24);
 106     a[11] = LOAD32_L(k + 28);
 107     a[ 0] = CHACHA_A256;
 108     a[ 1] = CHACHA_B256;
 109     a[ 2] = CHACHA_C256;
 110     a[ 3] = CHACHA_D256;
 111   }
 112 }
 113
 114 /*----- ChaCha implementation ---------------------------------------------*/
 115
 116 /* --- @chacha_init@ --- *
 117  *
 118  * Arguments:   @chacha_ctx *ctx@ = context to fill in
 119  *              @const void *key@ = pointer to key material
 120  *              @size_t ksz@ = size of key (either 32 or 16)
 121  *              @const void *nonce@ = initial nonce, or null
 122  *
 123  * Returns:     ---
 124  *
 125  * Use:         Initializes a ChaCha context ready for use.
 126  */
 127
 128 void chacha_init(chacha_ctx *ctx, const void *key, size_t ksz,
 129                   const void *nonce)
 130 {
 131   static const octet zerononce[CHACHA_NONCESZ];
 132
 133   populate(ctx->a, key, ksz);
 134   chacha_setnonce(ctx, nonce ? nonce : zerononce);
 135 }
 136
 137 /* --- @chacha_setnonce@ --- *
 138  *
 139  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 140  *              @const void *nonce@ = the nonce (@CHACHA_NONCESZ@ bytes)
 141  *
 142  * Returns:     ---
 143  *
 144  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 145  *              different message.  The stream position is reset to zero (see
 146  *              @chacha_seek@ etc.).
 147  */
 148
 149 void chacha_setnonce(chacha_ctx *ctx, const void *nonce)
 150 {
 151   const octet *n = nonce;
 152
 153   ctx->a[14] = LOAD32_L(n + 0);
 154   ctx->a[15] = LOAD32_L(n + 4);
 155   chacha_seek(ctx, 0);
 156 }
 157
 158 /* --- @chacha_seek@, @chacha_seeku64@ --- *
 159  *
 160  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 161  *              @unsigned long i@, @kludge64 i@ = new position to set
 162  *
 163  * Returns:     ---
 164  *
 165  * Use:         Sets a new stream position, in units of Chacha output
 166  *              blocks, which are @CHACHA_OUTSZ@ bytes each.  Byte
 167  *              granularity can be achieved by calling @chachaR_encrypt@
 168  *              appropriately.
 169  */
 170
 171 void chacha_seek(chacha_ctx *ctx, unsigned long i)
 172   { kludge64 ii; ASSIGN64(ii, i); chacha_seeku64(ctx, ii); }
 173
 174 void chacha_seeku64(chacha_ctx *ctx, kludge64 i)
 175 {
 176   ctx->a[12] = LO64(i); ctx->a[13] = HI64(i);
 177   ctx->bufi = CHACHA_OUTSZ;
 178 }
 179
 180 /* --- @chacha_tell@, @chacha_tellu64@ --- *
 181  *
 182  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 183  *
 184  * Returns:     The current position in the output stream, in blocks,
 185  *              rounding upwards.
 186  */
 187
 188 unsigned long chacha_tell(chacha_ctx *ctx)
 189   { kludge64 i = chacha_tellu64(ctx); return (GET64(unsigned long, i)); }
 190
 191 kludge64 chacha_tellu64(chacha_ctx *ctx)
 192   { kludge64 i; SET64(i, ctx->a[9], ctx->a[8]); return (i); }
 193
 194 /* --- @chacha{,12,8}_encrypt@ --- *
 195  *
 196  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 197  *              @const void *src@ = source buffer (or null)
 198  *              @void *dest@ = destination buffer (or null)
 199  *              @size_t sz@ = size of the buffers
 200  *
 201  * Returns:     ---
 202  *
 203  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 204  *              ChaCha works by XORing plaintext with a keystream, so
 205  *              encryption and decryption are the same operation.  If @dest@
 206  *              is null then ignore @src@ and skip @sz@ bytes of the
 207  *              keystream.  If @src@ is null, then just write the keystream
 208  *              to @dest@.
 209  */
 210
 211 #define CHACHA_ENCRYPT(r, ctx, src, dest, sz)                           \
 212   chacha##r##_encrypt(ctx, src, dest, sz)
 213 #define DEFENCRYPT(r)                                                   \
 214   void CHACHA_ENCRYPT(r, chacha_ctx *ctx, const void *src,              \
 215                       void *dest, size_t sz)                            \
 216   {                                                                     \
 217     chacha_matrix b;                                                    \
 218     const octet *s = src;                                               \
 219     octet *d = dest;                                                    \
 220     size_t n;                                                           \
 221     kludge64 pos, delta;                                                \
 222                                                                         \
 223     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 224     if (!sz) return;                                                    \
 225                                                                         \
 226     if (!dest) {                                                        \
 227       n = sz/CHACHA_OUTSZ;                                              \
 228       pos = chacha_tellu64(ctx);                                        \
 229       ASSIGN64(delta, n);                                               \
 230       ADD64(pos, pos, delta);                                           \
 231       chacha_seeku64(ctx, pos);                                         \
 232       sz = sz%CHACHA_OUTSZ;                                             \
 233     } else if (!src) {                                                  \
 234       while (sz >= CHACHA_OUTSZ) {                                      \
 235         core(r, ctx->a, b);                                             \
 236         CHACHA_STEP(ctx->a);                                            \
 237         SALSA20_GENFULL(b, d);                                          \
 238         sz -= CHACHA_OUTSZ;                                             \
 239       }                                                                 \
 240     } else {                                                            \
 241       while (sz >= CHACHA_OUTSZ) {                                      \
 242         core(r, ctx->a, b);                                             \
 243         CHACHA_STEP(ctx->a);                                            \
 244         SALSA20_MIXFULL(b, d, s);                                       \
 245         sz -= CHACHA_OUTSZ;                                             \
 246       }                                                                 \
 247     }                                                                   \
 248                                                                         \
 249     if (sz) {                                                           \
 250       core(r, ctx->a, b);                                               \
 251       CHACHA_STEP(ctx->a);                                              \
 252       SALSA20_PREPBUF(ctx, b);                                          \
 253       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 254       assert(!sz);                                                      \
 255     }                                                                   \
 256   }
 257 CHACHA_VARS(DEFENCRYPT)
 258
 259 /*----- HChaCha implementation --------------------------------------------*/
 260
 261 #define HCHACHA_RAW(r, ctx, src, dest) hchacha##r##_raw(ctx, src, dest)
 262 #define HCHACHA_PRF(r, ctx, src, dest) hchacha##r##_prf(ctx, src, dest)
 263
 264 /* --- @hchacha{20,12,8}_prf@ --- *
 265  *
 266  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 267  *              @const void *src@ = the input (@HCHACHA_INSZ@ bytes)
 268  *              @void *dest@ = the output (@HCHACHA_OUTSZ@ bytes)
 269  *
 270  * Returns:     ---
 271  *
 272  * Use:         Apply the HChacha/r pseudorandom function to @src@, writing
 273  *              the result to @out@.
 274  */
 275
 276 #define DEFHCHACHA(r)                                                   \
 277   static void HCHACHA_RAW(r, chacha_matrix k,                           \
 278                           const uint32 *src, uint32 *dest)              \
 279   {                                                                     \
 280     chacha_matrix a;                                                    \
 281     int i;                                                              \
 282                                                                         \
 283     /* --- HChaCha, computed from full ChaCha --- *                     \
 284      *                                                                  \
 285      * The security proof makes use of the fact that HChaCha (i.e.,     \
 286      * without the final feedforward step) can be computed from full    \
 287      * ChaCha using only knowledge of the non-secret input.  I don't    \
 288      * want to compromise the performance of the main function by       \
 289      * making the feedforward step separate, but this operation is less \
 290      * speed critical, so we do it the harder way.                      \
 291      */                                                                 \
 292                                                                         \
 293     for (i = 0; i < 4; i++) k[12 + i] = src[i];                         \
 294     core(r, k, a);                                                      \
 295     for (i = 0; i < 8; i++) dest[i] = a[(i + 4)^4] - k[(i + 4)^4];      \
 296   }                                                                     \
 297                                                                         \
 298   void HCHACHA_PRF(r, chacha_ctx *ctx, const void *src, void *dest)     \
 299   {                                                                     \
 300     const octet *s = src;                                               \
 301     octet *d = dest;                                                    \
 302     uint32 in[4], out[8];                                               \
 303     int i;                                                              \
 304                                                                         \
 305     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 306     HCHACHA_RAW(r, ctx->a, in, out);                                    \
 307     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 308   }
 309 CHACHA_VARS(DEFHCHACHA)
 310
 311 /*----- XChaCha implementation -------------------------------------------*/
 312
 313 /* --- Some convenient macros for naming functions --- *
 314  *
 315  * Because the crypto core is involved in XChaCha/r's per-nonce setup, we
 316  * need to take an interest in the number of rounds in most of the various
 317  * functions, and it will probably help if we distinguish the context
 318  * structures for the various versions.
 319  */
 320
 321 #define XCHACHA_CTX(r) xchacha##r##_ctx
 322 #define XCHACHA_INIT(r, ctx, k, ksz, n) xchacha##r##_init(ctx, k, ksz, n)
 323 #define XCHACHA_SETNONCE(r, ctx, n) xchacha##r##_setnonce(ctx, n)
 324 #define XCHACHA_SEEK(r, ctx, i) xchacha##r##_seek(ctx, i)
 325 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 326 #define XCHACHA_TELL(r, ctx) xchacha##r##_tell(ctx)
 327 #define XCHACHA_TELLU64(r, ctx) xchacha##r##_tellu64(ctx)
 328 #define XCHACHA_ENCRYPT(r, ctx, src, dest, sz)                          \
 329   xchacha##r##_encrypt(ctx, src, dest, sz)
 330
 331 /* --- @xchacha{20,12,8}_init@ --- *
 332  *
 333  * Arguments:   @xchachaR_ctx *ctx@ = the context to fill in
 334  *              @const void *key@ = pointer to key material
 335  *              @size_t ksz@ = size of key (either 32 or 16)
 336  *              @const void *nonce@ = initial nonce, or null
 337  *
 338  * Returns:     ---
 339  *
 340  * Use:         Initializes an XChaCha/r context ready for use.
 341  *
 342  *              There is a different function for each number of rounds,
 343  *              unlike for plain ChaCha.
 344  */
 345
 346 #define DEFXINIT(r)                                                     \
 347   void XCHACHA_INIT(r, XCHACHA_CTX(r) *ctx,                             \
 348                     const void *key, size_t ksz, const void *nonce)     \
 349   {                                                                     \
 350     static const octet zerononce[XCHACHA_NONCESZ];                      \
 351                                                                         \
 352     populate(ctx->k, key, ksz);                                         \
 353     ctx->s.a[ 0] = CHACHA_A256;                                         \
 354     ctx->s.a[ 1] = CHACHA_B256;                                         \
 355     ctx->s.a[ 2] = CHACHA_C256;                                         \
 356     ctx->s.a[ 3] = CHACHA_D256;                                         \
 357     XCHACHA_SETNONCE(r, ctx, nonce ? nonce : zerononce);                \
 358   }
 359 CHACHA_VARS(DEFXINIT)
 360
 361 /* --- @xchacha{20,12,8}_setnonce@ --- *
 362  *
 363  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 364  *              @const void *nonce@ = the nonce (@XCHACHA_NONCESZ@ bytes)
 365  *
 366  * Returns:     ---
 367  *
 368  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 369  *              different message.  The stream position is reset to zero (see
 370  *              @chacha_seek@ etc.).
 371  *
 372  *              There is a different function for each number of rounds,
 373  *              unlike for plain ChaCha.
 374  */
 375
 376 #define DEFXNONCE(r)                                                    \
 377   void XCHACHA_SETNONCE(r, XCHACHA_CTX(r) *ctx, const void *nonce)      \
 378   {                                                                     \
 379     const octet *n = nonce;                                             \
 380     uint32 in[4];                                                       \
 381     int i;                                                              \
 382                                                                         \
 383     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 384     HCHACHA_RAW(r, ctx->k, in, ctx->s.a + 4);                           \
 385     chacha_setnonce(&ctx->s, n + 16);                                   \
 386   }
 387 CHACHA_VARS(DEFXNONCE)
 388
 389 /* --- @xchacha{20,12,8}_seek@, @xchacha{20,12,8}_seeku64@ --- *
 390  *
 391  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 392  *              @unsigned long i@, @kludge64 i@ = new position to set
 393  *
 394  * Returns:     ---
 395  *
 396  * Use:         Sets a new stream position, in units of ChaCha output
 397  *              blocks, which are @XCHACHA_OUTSZ@ bytes each.  Byte
 398  *              granularity can be achieved by calling @xchachaR_encrypt@
 399  *              appropriately.
 400  *
 401  *              There is a different function for each number of rounds,
 402  *              unlike for plain ChaCha, because the context structures are
 403  *              different.
 404  */
 405
 406 /* --- @xchacha{20,12,8}_tell@, @xchacha{20,12,8}_tellu64@ --- *
 407  *
 408  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 409  *
 410  * Returns:     The current position in the output stream, in blocks,
 411  *              rounding upwards.
 412  *
 413  *              There is a different function for each number of rounds,
 414  *              unlike for plain ChaCha, because the context structures are
 415  *              different.
 416  */
 417
 418 /* --- @xchacha{,12,8}_encrypt@ --- *
 419  *
 420  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 421  *              @const void *src@ = source buffer (or null)
 422  *              @void *dest@ = destination buffer (or null)
 423  *              @size_t sz@ = size of the buffers
 424  *
 425  * Returns:     ---
 426  *
 427  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 428  *              XChaCha works by XORing plaintext with a keystream, so
 429  *              encryption and decryption are the same operation.  If @dest@
 430  *              is null then ignore @src@ and skip @sz@ bytes of the
 431  *              keystream.  If @src@ is null, then just write the keystream
 432  *              to @dest@.
 433  */
 434
 435 #define DEFXPASSTHRU(r)                                                 \
 436   void XCHACHA_SEEK(r, XCHACHA_CTX(r) *ctx, unsigned long i)            \
 437     { chacha_seek(&ctx->s, i); }                                        \
 438   void XCHACHA_SEEKU64(r, XCHACHA_CTX(r) *ctx, kludge64 i)              \
 439     { chacha_seeku64(&ctx->s, i); }                                     \
 440   unsigned long XCHACHA_TELL(r, XCHACHA_CTX(r) *ctx)                    \
 441     { return chacha_tell(&ctx->s); }                                    \
 442   kludge64 XCHACHA_TELLU64(r, XCHACHA_CTX(r) *ctx)                      \
 443     { return chacha_tellu64(&ctx->s); }                                 \
 444   void XCHACHA_ENCRYPT(r, XCHACHA_CTX(r) *ctx,                          \
 445                         const void *src, void *dest, size_t sz)         \
 446     { CHACHA_ENCRYPT(r, &ctx->s, src, dest, sz); }
 447 CHACHA_VARS(DEFXPASSTHRU)
 448
 449 /*----- Generic cipher interface ------------------------------------------*/
 450
 451 typedef struct gctx { gcipher c; chacha_ctx ctx; } gctx;
 452
 453 static void gsetiv(gcipher *c, const void *iv)
 454   { gctx *g = (gctx *)c; chacha_setnonce(&g->ctx, iv); }
 455
 456 static void gdestroy(gcipher *c)
 457   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 458
 459 #define DEFGCIPHER(r)                                                   \
 460                                                                         \
 461   static const gcipher_ops gops_##r;                                    \
 462                                                                         \
 463   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 464   {                                                                     \
 465     gctx *g = S_CREATE(gctx);                                           \
 466     g->c.ops = &gops_##r;                                               \
 467     chacha_init(&g->ctx, k, sz, 0);                                     \
 468     return (&g->c);                                                     \
 469   }                                                                     \
 470                                                                         \
 471   static void gencrypt_##r(gcipher *c, const void *s,                   \
 472                            void *t, size_t sz)                          \
 473     { gctx *g = (gctx *)c; CHACHA_ENCRYPT(r, &g->ctx, s, t, sz); }      \
 474                                                                         \
 475   static const gcipher_ops gops_##r = {                                 \
 476     &chacha##r,                                                         \
 477     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 478   };                                                                    \
 479                                                                         \
 480   const gccipher chacha##r = {                                          \
 481     "chacha" #r, chacha_keysz,                                          \
 482     CHACHA_NONCESZ, ginit_##r                                           \
 483   };
 484
 485 CHACHA_VARS(DEFGCIPHER)
 486
 487 #define DEFGXCIPHER(r)                                                  \
 488                                                                         \
 489   typedef struct { gcipher c; XCHACHA_CTX(r) ctx; } gxctx_##r;          \
 490                                                                         \
 491   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 492     { gxctx_##r *g = (gxctx_##r *)c; XCHACHA_SETNONCE(r, &g->ctx, iv); } \
 493                                                                         \
 494   static void gxdestroy_##r(gcipher *c)                                 \
 495     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 496                                                                         \
 497   static const gcipher_ops gxops_##r;                                   \
 498                                                                         \
 499   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 500   {                                                                     \
 501     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 502     g->c.ops = &gxops_##r;                                              \
 503     XCHACHA_INIT(r, &g->ctx, k, sz, 0);                                 \
 504     return (&g->c);                                                     \
 505   }                                                                     \
 506                                                                         \
 507   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 508                             void *t, size_t sz)                         \
 509   {                                                                     \
 510     gxctx_##r *g = (gxctx_##r *)c;                                      \
 511     XCHACHA_ENCRYPT(r, &g->ctx, s, t, sz);                              \
 512   }                                                                     \
 513                                                                         \
 514   static const gcipher_ops gxops_##r = {                                \
 515     &xchacha##r,                                                        \
 516     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 517   };                                                                    \
 518                                                                         \
 519   const gccipher xchacha##r = {                                         \
 520     "xchacha" #r, chacha_keysz,                                         \
 521     CHACHA_NONCESZ, gxinit_##r                                          \
 522   };
 523
 524 CHACHA_VARS(DEFGXCIPHER)
 525
 526 /*----- Generic random number generator interface -------------------------*/
 527
 528 typedef struct grops {
 529   size_t noncesz;
 530   void (*seek)(void *, kludge64);
 531   kludge64 (*tell)(void *);
 532   void (*setnonce)(void *, const void *);
 533   void (*generate)(void *, void *, size_t);
 534 } grops;
 535
 536 typedef struct grbasectx {
 537   grand r;
 538   const grops *ops;
 539 } grbasectx;
 540
 541 static int grmisc(grand *r, unsigned op, ...)
 542 {
 543   octet buf[XCHACHA_NONCESZ];
 544   grbasectx *g = (grbasectx *)r;
 545   grand *rr;
 546   const octet *p;
 547   size_t sz;
 548   uint32 i;
 549   unsigned long ul;
 550   kludge64 pos;
 551   va_list ap;
 552   int rc = 0;
 553
 554   va_start(ap, op);
 555
 556   switch (op) {
 557     case GRAND_CHECK:
 558       switch (va_arg(ap, unsigned)) {
 559         case GRAND_CHECK:
 560         case GRAND_SEEDINT:
 561         case GRAND_SEEDUINT32:
 562         case GRAND_SEEDBLOCK:
 563         case GRAND_SEEDRAND:
 564         case CHACHA_SEEK:
 565         case CHACHA_SEEKU64:
 566         case CHACHA_TELL:
 567         case CHACHA_TELLU64:
 568           rc = 1;
 569           break;
 570         default:
 571           rc = 0;
 572           break;
 573       }
 574       break;
 575
 576     case GRAND_SEEDINT:
 577       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 578       memset(buf + 4, 0, g->ops->noncesz - 4);
 579       g->ops->setnonce(g, buf);
 580       break;
 581     case GRAND_SEEDUINT32:
 582       i = va_arg(ap, uint32); STORE32_L(buf, i);
 583       memset(buf + 4, 0, g->ops->noncesz - 4);
 584       g->ops->setnonce(g, buf);
 585       break;
 586     case GRAND_SEEDBLOCK:
 587       p = va_arg(ap, const void *);
 588       sz = va_arg(ap, size_t);
 589       if (sz < g->ops->noncesz) {
 590         memcpy(buf, p, sz);
 591         memset(buf + sz, 0, g->ops->noncesz - sz);
 592         p = buf;
 593       }
 594       g->ops->setnonce(g, p);
 595       break;
 596     case GRAND_SEEDRAND:
 597       rr = va_arg(ap, grand *);
 598       rr->ops->fill(rr, buf, g->ops->noncesz);
 599       g->ops->setnonce(g, buf);
 600       break;
 601     case CHACHA_SEEK:
 602       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 603       g->ops->seek(g, pos);
 604       break;
 605     case CHACHA_SEEKU64:
 606       pos = va_arg(ap, kludge64);
 607       g->ops->seek(g, pos);
 608       break;
 609     case CHACHA_TELL:
 610       pos = g->ops->tell(g);
 611       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 612       break;
 613     case CHACHA_TELLU64:
 614       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 615       break;
 616     default:
 617       GRAND_BADOP;
 618       break;
 619   }
 620
 621   return (rc);
 622 }
 623
 624 static octet grbyte(grand *r)
 625 {
 626   grbasectx *g = (grbasectx *)r;
 627   octet o;
 628   g->ops->generate(g, &o, 1);
 629   return (o);
 630 }
 631
 632 static uint32 grword(grand *r)
 633 {
 634   grbasectx *g = (grbasectx *)r;
 635   octet b[4];
 636   g->ops->generate(g, b, sizeof(b));
 637   return (LOAD32_L(b));
 638 }
 639
 640 static void grfill(grand *r, void *p, size_t sz)
 641 {
 642   grbasectx *g = (grbasectx *)r;
 643   g->ops->generate(r, p, sz);
 644 }
 645
 646 typedef struct grctx {
 647   grbasectx r;
 648   chacha_ctx ctx;
 649 } grctx;
 650
 651 static void gr_seek(void *r, kludge64 pos)
 652   { grctx *g = r; chacha_seeku64(&g->ctx, pos); }
 653
 654 static kludge64 gr_tell(void *r)
 655   { grctx *g = r; return (chacha_tellu64(&g->ctx)); }
 656
 657 static void gr_setnonce(void *r, const void *n)
 658   { grctx *g = r; chacha_setnonce(&g->ctx, n); }
 659
 660 static void grdestroy(grand *r)
 661   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 662
 663 #define DEFGRAND(rr)                                                    \
 664                                                                         \
 665   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 666     { grctx *g = r; CHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }            \
 667                                                                         \
 668   static const grops grops_##rr =                                       \
 669     { CHACHA_NONCESZ, gr_seek, gr_tell,                                 \
 670       gr_setnonce, gr_generate_##rr };                                  \
 671                                                                         \
 672   static const grand_ops grops_rand_##rr = {                            \
 673     "chacha" #rr, GRAND_CRYPTO, 0,                                      \
 674     grmisc, grdestroy, grword,                                          \
 675     grbyte, grword, grand_range, grfill                                 \
 676   };                                                                    \
 677                                                                         \
 678   grand *chacha##rr##_rand(const void *k, size_t ksz, const void *n)    \
 679   {                                                                     \
 680     grctx *g = S_CREATE(g);                                             \
 681     g->r.r.ops = &grops_rand_##rr;                                      \
 682     g->r.ops = &grops_##rr;                                             \
 683     chacha_init(&g->ctx, k, ksz, n);                                    \
 684     return (&g->r.r);                                                   \
 685   }
 686 CHACHA_VARS(DEFGRAND)
 687
 688 #define DEFXGRAND(rr)                                                   \
 689                                                                         \
 690   typedef struct grxctx_##rr {                                          \
 691     grbasectx r;                                                        \
 692     XCHACHA_CTX(rr) ctx;                                                \
 693   } grxctx_##rr;                                                        \
 694                                                                         \
 695   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 696     { grxctx_##rr *g = r; XCHACHA_SEEKU64(rr, &g->ctx, pos); }          \
 697                                                                         \
 698   static kludge64 grx_tell_##rr(void *r)                                \
 699     { grxctx_##rr *g = r; return (XCHACHA_TELLU64(rr, &g->ctx)); }      \
 700                                                                         \
 701   static void grx_setnonce_##rr(void *r, const void *n)                 \
 702     { grxctx_##rr *g = r; XCHACHA_SETNONCE(rr, &g->ctx, n); }           \
 703                                                                         \
 704   static void grxdestroy_##rr(grand *r)                                 \
 705     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 706                                                                         \
 707   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 708     { grxctx_##rr *g = r; XCHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }     \
 709                                                                         \
 710   static const grops grxops_##rr =                                      \
 711     { XCHACHA_NONCESZ, grx_seek_##rr, grx_tell_##rr,                    \
 712       grx_setnonce_##rr, grx_generate_##rr };                           \
 713                                                                         \
 714   static const grand_ops grxops_rand_##rr = {                           \
 715     "xchacha" #rr, GRAND_CRYPTO, 0,                                     \
 716     grmisc, grxdestroy_##rr, grword,                                    \
 717     grbyte, grword, grand_range, grfill                                 \
 718   };                                                                    \
 719                                                                         \
 720   grand *xchacha##rr##_rand(const void *k, size_t ksz, const void *n)   \
 721   {                                                                     \
 722     grxctx_##rr *g = S_CREATE(g);                                       \
 723     g->r.r.ops = &grxops_rand_##rr;                                     \
 724     g->r.ops = &grxops_##rr;                                            \
 725     XCHACHA_INIT(rr, &g->ctx, k, ksz, n);                               \
 726     return (&g->r.r);                                                   \
 727   }
 728 CHACHA_VARS(DEFXGRAND)
 729
 730 /*----- Test rig ----------------------------------------------------------*/
 731
 732 #ifdef TEST_RIG
 733
 734 #include <stdio.h>
 735 #include <string.h>
 736
 737 #include <mLib/quis.h>
 738 #include <mLib/testrig.h>
 739
 740 #define DEFVCORE(r)                                                     \
 741   static int v_core_##r(dstr *v)                                        \
 742   {                                                                     \
 743     chacha_matrix a, b;                                                 \
 744     dstr d = DSTR_INIT;                                                 \
 745     int i, n;                                                           \
 746     int ok = 1;                                                         \
 747                                                                         \
 748     DENSURE(&d, CHACHA_OUTSZ); d.len = CHACHA_OUTSZ;                    \
 749     n = *(int *)v[0].buf;                                               \
 750     for (i = 0; i < CHACHA_OUTSZ/4; i++)                                \
 751       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 752     for (i = 0; i < n; i++) {                                           \
 753       core(r, a, b);                                                    \
 754       memcpy(a, b, sizeof(a));                                          \
 755     }                                                                   \
 756     for (i = 0; i < CHACHA_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]);  \
 757                                                                         \
 758     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 759       ok = 0;                                                           \
 760       printf("\nfail core:"                                             \
 761              "\n\titerations = %d"                                      \
 762              "\n\tin       = ", n);                                     \
 763       type_hex.dump(&v[1], stdout);                                     \
 764       printf("\n\texpected   = ");                                      \
 765       type_hex.dump(&v[2], stdout);                                     \
 766       printf("\n\tcalculated = ");                                      \
 767       type_hex.dump(&d, stdout);                                        \
 768       putchar('\n');                                                    \
 769     }                                                                   \
 770                                                                         \
 771     dstr_destroy(&d);                                                   \
 772     return (ok);                                                        \
 773   }
 774 CHACHA_VARS(DEFVCORE)
 775
 776 #define CHACHA_CTX(r) chacha_ctx
 777 #define CHACHA_INIT(r, ctx, k, ksz, n) chacha_init(ctx, k, ksz, n)
 778 #define CHACHA_SEEKU64(r, ctx, i) chacha_seeku64(ctx, i)
 779 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 780
 781 #define DEFxVENC(base, BASE, r)                                         \
 782   static int v_encrypt_##base##_##r(dstr *v)                            \
 783   {                                                                     \
 784     BASE##_CTX(r) ctx;                                                  \
 785     dstr d = DSTR_INIT;                                                 \
 786     kludge64 pos;                                                       \
 787     const octet *p, *p0;                                                \
 788     octet *q;                                                           \
 789     size_t sz, sz0, step;                                               \
 790     unsigned long skip;                                                 \
 791     int ok = 1;                                                         \
 792                                                                         \
 793     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 794     else { p0 = 0; sz0 = v[5].len; }                                    \
 795     DENSURE(&d, sz0); d.len = sz0;                                      \
 796     skip = *(unsigned long *)v[3].buf;                                  \
 797                                                                         \
 798     step = 0;                                                           \
 799     while (step < sz0 + skip) {                                         \
 800       step = step ? 3*step + 4 : 1;                                     \
 801       if (step > sz0 + skip) step = sz0 + skip;                         \
 802       BASE##_INIT(r, &ctx, v[0].buf, v[0].len, v[1].buf);               \
 803       if (v[2].len) {                                                   \
 804         LOAD64_(pos, v[2].buf);                                         \
 805         BASE##_SEEKU64(r, &ctx, pos);                                   \
 806       }                                                                 \
 807                                                                         \
 808       for (sz = skip; sz >= step; sz -= step)                           \
 809         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 810       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 811       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 812            sz >= step;                                                  \
 813            sz -= step, q += step) {                                     \
 814         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 815         if (p) p += step;                                               \
 816       }                                                                 \
 817       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 818                                                                         \
 819       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 820         ok = 0;                                                         \
 821         printf("\nfail encrypt:"                                        \
 822                "\n\tstep           = %lu"                               \
 823                "\n\tkey    = ", (unsigned long)step);                   \
 824         type_hex.dump(&v[0], stdout);                                   \
 825         printf("\n\tnonce          = ");                                \
 826         type_hex.dump(&v[1], stdout);                                   \
 827         printf("\n\tposition   = ");                                    \
 828         type_hex.dump(&v[2], stdout);                                   \
 829         printf("\n\tskip           = %lu", skip);                       \
 830         printf("\n\tmessage    = ");                                    \
 831         type_hex.dump(&v[4], stdout);                                   \
 832         printf("\n\texpected   = ");                                    \
 833         type_hex.dump(&v[5], stdout);                                   \
 834         printf("\n\tcalculated = ");                                    \
 835         type_hex.dump(&d, stdout);                                      \
 836         putchar('\n');                                                  \
 837       }                                                                 \
 838     }                                                                   \
 839                                                                         \
 840     dstr_destroy(&d);                                                   \
 841     return (ok);                                                        \
 842   }
 843 #define DEFVENC(r) DEFxVENC(chacha, CHACHA, r)
 844 #define DEFXVENC(r) DEFxVENC(xchacha, XCHACHA, r)
 845 CHACHA_VARS(DEFVENC)
 846 CHACHA_VARS(DEFXVENC)
 847
 848 static test_chunk defs[] = {
 849 #define DEFxTAB(base, r)                                                \
 850   { #base #r, v_encrypt_##base##_##r,                                   \
 851     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 852       &type_hex, &type_hex, 0 } },
 853 #define DEFTAB(r)                                                       \
 854   { "chacha" #r "-core", v_core_##r,                                    \
 855     { &type_int, &type_hex, &type_hex, 0 } },                           \
 856   DEFxTAB(chacha, r)
 857 #define DEFXTAB(r) DEFxTAB(xchacha, r)
 858 CHACHA_VARS(DEFTAB)
 859 CHACHA_VARS(DEFXTAB)
 860   { 0, 0, { 0 } }
 861 };
 862
 863 int main(int argc, char *argv[])
 864 {
 865   test_run(argc, argv, defs, SRCDIR"/t/chacha");
 866   return (0);
 867 }
 868
 869 #endif
 870
 871 /*----- That's all, folks -------------------------------------------------*/