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 "config.h"
  31
  32 #include <stdarg.h>
  33
  34 #include <mLib/bits.h>
  35
  36 #include "arena.h"
  37 #include "chacha.h"
  38 #include "chacha-core.h"
  39 #include "dispatch.h"
  40 #include "gcipher.h"
  41 #include "grand.h"
  42 #include "keysz.h"
  43 #include "paranoia.h"
  44
  45 /*----- Global variables --------------------------------------------------*/
  46
  47 const octet chacha_keysz[] = { KSZ_SET, 32, 16, 10, 0 };
  48
  49 /*----- The ChaCha core function and utilities ----------------------------*/
  50
  51 /* --- @core@ --- *
  52  *
  53  * Arguments:   @unsigned r@ = number of rounds
  54  *              @const chacha_matrix src@ = input matrix
  55  *              @chacha_matrix dest@ = where to put the output
  56  *
  57  * Returns:     ---
  58  *
  59  *
  60  * Use:         Apply the ChaCha/r core function to @src@, writing the
  61  *              result to @dest@.  This consists of @r@ rounds followed by
  62  *              the feedforward step.
  63  */
  64
  65 CPU_DISPATCH(static, (void), void, core,
  66              (unsigned r, const chacha_matrix src, chacha_matrix dest),
  67              (r, src, dest), pick_core, simple_core);
  68
  69 static void simple_core(unsigned r, const chacha_matrix src,
  70                         chacha_matrix dest)
  71   { CHACHA_nR(dest, src, r); CHACHA_FFWD(dest, src); }
  72
  73 #if CPUFAM_X86 || CPUFAM_AMD64
  74 extern core__functype chacha_core_x86ish_sse2;
  75 #endif
  76
  77 #if CPUFAM_ARMEL
  78 extern core__functype chacha_core_arm_neon;
  79 #endif
  80
  81 static core__functype *pick_core(void)
  82 {
  83 #if CPUFAM_X86 || CPUFAM_AMD64
  84   DISPATCH_PICK_COND(chacha_core, chacha_core_x86ish_sse2,
  85                      cpu_feature_p(CPUFEAT_X86_SSE2));
  86 #endif
  87 #if CPUFAM_ARMEL
  88   DISPATCH_PICK_COND(chacha_core, chacha_core_arm_neon,
  89                      cpu_feature_p(CPUFEAT_ARM_NEON));
  90 #endif
  91   DISPATCH_PICK_FALLBACK(chacha_core, simple_core);
  92 }
  93
  94 /* --- @populate@ --- *
  95  *
  96  * Arguments:   @chacha_matrix a@ = a matrix to fill in
  97  *              @const void *key@ = pointer to key material
  98  *              @size_t ksz@ = size of key
  99  *
 100  * Returns:     ---
 101  *
 102  * Use:         Fills in a ChaCha matrix from the key, setting the
 103  *              appropriate constants according to the key length.  The nonce
 104  *              and position words are left uninitialized.
 105  */
 106
 107 static void populate(chacha_matrix a, const void *key, size_t ksz)
 108 {
 109   const octet *k = key;
 110
 111   KSZ_ASSERT(chacha, ksz);
 112
 113   a[ 4] = LOAD32_L(k +  0);
 114   a[ 5] = LOAD32_L(k +  4);
 115   if (ksz == 10) {
 116     a[ 6] = LOAD16_L(k +  8);
 117     a[ 7] = 0;
 118   } else {
 119     a[ 6] = LOAD32_L(k +  8);
 120     a[ 7] = LOAD32_L(k + 12);
 121   }
 122   if (ksz <= 16) {
 123     a[ 8] = a[ 4];
 124     a[ 9] = a[ 5];
 125     a[10] = a[ 6];
 126     a[11] = a[ 7];
 127     a[ 0] = CHACHA_A128;
 128     a[ 1] = CHACHA_B128;
 129     a[ 2] = ksz == 10 ? CHACHA_C80 : CHACHA_C128;
 130     a[ 3] = CHACHA_D128;
 131   } else {
 132     a[ 8] = LOAD32_L(k + 16);
 133     a[ 9] = LOAD32_L(k + 20);
 134     a[10] = LOAD32_L(k + 24);
 135     a[11] = LOAD32_L(k + 28);
 136     a[ 0] = CHACHA_A256;
 137     a[ 1] = CHACHA_B256;
 138     a[ 2] = CHACHA_C256;
 139     a[ 3] = CHACHA_D256;
 140   }
 141 }
 142
 143 /*----- ChaCha implementation ---------------------------------------------*/
 144
 145 /* --- @chacha_init@ --- *
 146  *
 147  * Arguments:   @chacha_ctx *ctx@ = context to fill in
 148  *              @const void *key@ = pointer to key material
 149  *              @size_t ksz@ = size of key (either 32 or 16)
 150  *              @const void *nonce@ = initial nonce, or null
 151  *
 152  * Returns:     ---
 153  *
 154  * Use:         Initializes a ChaCha context ready for use.
 155  */
 156
 157 void chacha_init(chacha_ctx *ctx, const void *key, size_t ksz,
 158                   const void *nonce)
 159 {
 160   static const octet zerononce[CHACHA_NONCESZ];
 161
 162   populate(ctx->a, key, ksz);
 163   chacha_setnonce(ctx, nonce ? nonce : zerononce);
 164 }
 165
 166 /* --- @chacha_setnonce@ --- *
 167  *
 168  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 169  *              @const void *nonce@ = the nonce (@CHACHA_NONCESZ@ bytes)
 170  *
 171  * Returns:     ---
 172  *
 173  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 174  *              different message.  The stream position is reset to zero (see
 175  *              @chacha_seek@ etc.).
 176  */
 177
 178 void chacha_setnonce(chacha_ctx *ctx, const void *nonce)
 179 {
 180   const octet *n = nonce;
 181
 182   ctx->a[14] = LOAD32_L(n + 0);
 183   ctx->a[15] = LOAD32_L(n + 4);
 184   chacha_seek(ctx, 0);
 185 }
 186
 187 /* --- @chacha_seek@, @chacha_seeku64@ --- *
 188  *
 189  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 190  *              @unsigned long i@, @kludge64 i@ = new position to set
 191  *
 192  * Returns:     ---
 193  *
 194  * Use:         Sets a new stream position, in units of Chacha output
 195  *              blocks, which are @CHACHA_OUTSZ@ bytes each.  Byte
 196  *              granularity can be achieved by calling @chachaR_encrypt@
 197  *              appropriately.
 198  */
 199
 200 void chacha_seek(chacha_ctx *ctx, unsigned long i)
 201   { kludge64 ii; ASSIGN64(ii, i); chacha_seeku64(ctx, ii); }
 202
 203 void chacha_seeku64(chacha_ctx *ctx, kludge64 i)
 204 {
 205   ctx->a[12] = LO64(i); ctx->a[13] = HI64(i);
 206   ctx->bufi = CHACHA_OUTSZ;
 207 }
 208
 209 /* --- @chacha_tell@, @chacha_tellu64@ --- *
 210  *
 211  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 212  *
 213  * Returns:     The current position in the output stream, in blocks,
 214  *              rounding upwards.
 215  */
 216
 217 unsigned long chacha_tell(chacha_ctx *ctx)
 218   { kludge64 i = chacha_tellu64(ctx); return (GET64(unsigned long, i)); }
 219
 220 kludge64 chacha_tellu64(chacha_ctx *ctx)
 221   { kludge64 i; SET64(i, ctx->a[9], ctx->a[8]); return (i); }
 222
 223 /* --- @chacha{,12,8}_encrypt@ --- *
 224  *
 225  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 226  *              @const void *src@ = source buffer (or null)
 227  *              @void *dest@ = destination buffer (or null)
 228  *              @size_t sz@ = size of the buffers
 229  *
 230  * Returns:     ---
 231  *
 232  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 233  *              ChaCha works by XORing plaintext with a keystream, so
 234  *              encryption and decryption are the same operation.  If @dest@
 235  *              is null then ignore @src@ and skip @sz@ bytes of the
 236  *              keystream.  If @src@ is null, then just write the keystream
 237  *              to @dest@.
 238  */
 239
 240 #define CHACHA_ENCRYPT(r, ctx, src, dest, sz)                           \
 241   chacha##r##_encrypt(ctx, src, dest, sz)
 242 #define DEFENCRYPT(r)                                                   \
 243   void CHACHA_ENCRYPT(r, chacha_ctx *ctx, const void *src,              \
 244                       void *dest, size_t sz)                            \
 245   {                                                                     \
 246     chacha_matrix b;                                                    \
 247     const octet *s = src;                                               \
 248     octet *d = dest;                                                    \
 249     size_t n;                                                           \
 250     kludge64 pos, delta;                                                \
 251                                                                         \
 252     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 253     if (!sz) return;                                                    \
 254                                                                         \
 255     if (!dest) {                                                        \
 256       n = sz/CHACHA_OUTSZ;                                              \
 257       pos = chacha_tellu64(ctx);                                        \
 258       ASSIGN64(delta, n);                                               \
 259       ADD64(pos, pos, delta);                                           \
 260       chacha_seeku64(ctx, pos);                                         \
 261       sz = sz%CHACHA_OUTSZ;                                             \
 262     } else if (!src) {                                                  \
 263       while (sz >= CHACHA_OUTSZ) {                                      \
 264         core(r, ctx->a, b);                                             \
 265         CHACHA_STEP(ctx->a);                                            \
 266         SALSA20_GENFULL(b, d);                                          \
 267         sz -= CHACHA_OUTSZ;                                             \
 268       }                                                                 \
 269     } else {                                                            \
 270       while (sz >= CHACHA_OUTSZ) {                                      \
 271         core(r, ctx->a, b);                                             \
 272         CHACHA_STEP(ctx->a);                                            \
 273         SALSA20_MIXFULL(b, d, s);                                       \
 274         sz -= CHACHA_OUTSZ;                                             \
 275       }                                                                 \
 276     }                                                                   \
 277                                                                         \
 278     if (sz) {                                                           \
 279       core(r, ctx->a, b);                                               \
 280       CHACHA_STEP(ctx->a);                                              \
 281       SALSA20_PREPBUF(ctx, b);                                          \
 282       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 283       assert(!sz);                                                      \
 284     }                                                                   \
 285   }
 286 CHACHA_VARS(DEFENCRYPT)
 287
 288 /*----- HChaCha implementation --------------------------------------------*/
 289
 290 #define HCHACHA_RAW(r, ctx, src, dest) hchacha##r##_raw(ctx, src, dest)
 291 #define HCHACHA_PRF(r, ctx, src, dest) hchacha##r##_prf(ctx, src, dest)
 292
 293 /* --- @hchacha{20,12,8}_prf@ --- *
 294  *
 295  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 296  *              @const void *src@ = the input (@HCHACHA_INSZ@ bytes)
 297  *              @void *dest@ = the output (@HCHACHA_OUTSZ@ bytes)
 298  *
 299  * Returns:     ---
 300  *
 301  * Use:         Apply the HChacha/r pseudorandom function to @src@, writing
 302  *              the result to @out@.
 303  */
 304
 305 #define DEFHCHACHA(r)                                                   \
 306   static void HCHACHA_RAW(r, chacha_matrix k,                           \
 307                           const uint32 *src, uint32 *dest)              \
 308   {                                                                     \
 309     chacha_matrix a;                                                    \
 310     int i;                                                              \
 311                                                                         \
 312     /* --- HChaCha, computed from full ChaCha --- *                     \
 313      *                                                                  \
 314      * The security proof makes use of the fact that HChaCha (i.e.,     \
 315      * without the final feedforward step) can be computed from full    \
 316      * ChaCha using only knowledge of the non-secret input.  I don't    \
 317      * want to compromise the performance of the main function by       \
 318      * making the feedforward step separate, but this operation is less \
 319      * speed critical, so we do it the harder way.                      \
 320      */                                                                 \
 321                                                                         \
 322     for (i = 0; i < 4; i++) k[12 + i] = src[i];                         \
 323     core(r, k, a);                                                      \
 324     for (i = 0; i < 8; i++) dest[i] = a[(i + 4)^4] - k[(i + 4)^4];      \
 325   }                                                                     \
 326                                                                         \
 327   void HCHACHA_PRF(r, chacha_ctx *ctx, const void *src, void *dest)     \
 328   {                                                                     \
 329     const octet *s = src;                                               \
 330     octet *d = dest;                                                    \
 331     uint32 in[4], out[8];                                               \
 332     int i;                                                              \
 333                                                                         \
 334     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 335     HCHACHA_RAW(r, ctx->a, in, out);                                    \
 336     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 337   }
 338 CHACHA_VARS(DEFHCHACHA)
 339
 340 /*----- XChaCha implementation -------------------------------------------*/
 341
 342 /* --- Some convenient macros for naming functions --- *
 343  *
 344  * Because the crypto core is involved in XChaCha/r's per-nonce setup, we
 345  * need to take an interest in the number of rounds in most of the various
 346  * functions, and it will probably help if we distinguish the context
 347  * structures for the various versions.
 348  */
 349
 350 #define XCHACHA_CTX(r) xchacha##r##_ctx
 351 #define XCHACHA_INIT(r, ctx, k, ksz, n) xchacha##r##_init(ctx, k, ksz, n)
 352 #define XCHACHA_SETNONCE(r, ctx, n) xchacha##r##_setnonce(ctx, n)
 353 #define XCHACHA_SEEK(r, ctx, i) xchacha##r##_seek(ctx, i)
 354 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 355 #define XCHACHA_TELL(r, ctx) xchacha##r##_tell(ctx)
 356 #define XCHACHA_TELLU64(r, ctx) xchacha##r##_tellu64(ctx)
 357 #define XCHACHA_ENCRYPT(r, ctx, src, dest, sz)                          \
 358   xchacha##r##_encrypt(ctx, src, dest, sz)
 359
 360 /* --- @xchacha{20,12,8}_init@ --- *
 361  *
 362  * Arguments:   @xchachaR_ctx *ctx@ = the context to fill in
 363  *              @const void *key@ = pointer to key material
 364  *              @size_t ksz@ = size of key (either 32 or 16)
 365  *              @const void *nonce@ = initial nonce, or null
 366  *
 367  * Returns:     ---
 368  *
 369  * Use:         Initializes an XChaCha/r context ready for use.
 370  *
 371  *              There is a different function for each number of rounds,
 372  *              unlike for plain ChaCha.
 373  */
 374
 375 #define DEFXINIT(r)                                                     \
 376   void XCHACHA_INIT(r, XCHACHA_CTX(r) *ctx,                             \
 377                     const void *key, size_t ksz, const void *nonce)     \
 378   {                                                                     \
 379     static const octet zerononce[XCHACHA_NONCESZ];                      \
 380                                                                         \
 381     populate(ctx->k, key, ksz);                                         \
 382     ctx->s.a[ 0] = CHACHA_A256;                                         \
 383     ctx->s.a[ 1] = CHACHA_B256;                                         \
 384     ctx->s.a[ 2] = CHACHA_C256;                                         \
 385     ctx->s.a[ 3] = CHACHA_D256;                                         \
 386     XCHACHA_SETNONCE(r, ctx, nonce ? nonce : zerononce);                \
 387   }
 388 CHACHA_VARS(DEFXINIT)
 389
 390 /* --- @xchacha{20,12,8}_setnonce@ --- *
 391  *
 392  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 393  *              @const void *nonce@ = the nonce (@XCHACHA_NONCESZ@ bytes)
 394  *
 395  * Returns:     ---
 396  *
 397  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 398  *              different message.  The stream position is reset to zero (see
 399  *              @chacha_seek@ etc.).
 400  *
 401  *              There is a different function for each number of rounds,
 402  *              unlike for plain ChaCha.
 403  */
 404
 405 #define DEFXNONCE(r)                                                    \
 406   void XCHACHA_SETNONCE(r, XCHACHA_CTX(r) *ctx, const void *nonce)      \
 407   {                                                                     \
 408     const octet *n = nonce;                                             \
 409     uint32 in[4];                                                       \
 410     int i;                                                              \
 411                                                                         \
 412     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 413     HCHACHA_RAW(r, ctx->k, in, ctx->s.a + 4);                           \
 414     chacha_setnonce(&ctx->s, n + 16);                                   \
 415   }
 416 CHACHA_VARS(DEFXNONCE)
 417
 418 /* --- @xchacha{20,12,8}_seek@, @xchacha{20,12,8}_seeku64@ --- *
 419  *
 420  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 421  *              @unsigned long i@, @kludge64 i@ = new position to set
 422  *
 423  * Returns:     ---
 424  *
 425  * Use:         Sets a new stream position, in units of ChaCha output
 426  *              blocks, which are @XCHACHA_OUTSZ@ bytes each.  Byte
 427  *              granularity can be achieved by calling @xchachaR_encrypt@
 428  *              appropriately.
 429  *
 430  *              There is a different function for each number of rounds,
 431  *              unlike for plain ChaCha, because the context structures are
 432  *              different.
 433  */
 434
 435 /* --- @xchacha{20,12,8}_tell@, @xchacha{20,12,8}_tellu64@ --- *
 436  *
 437  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 438  *
 439  * Returns:     The current position in the output stream, in blocks,
 440  *              rounding upwards.
 441  *
 442  *              There is a different function for each number of rounds,
 443  *              unlike for plain ChaCha, because the context structures are
 444  *              different.
 445  */
 446
 447 /* --- @xchacha{,12,8}_encrypt@ --- *
 448  *
 449  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 450  *              @const void *src@ = source buffer (or null)
 451  *              @void *dest@ = destination buffer (or null)
 452  *              @size_t sz@ = size of the buffers
 453  *
 454  * Returns:     ---
 455  *
 456  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 457  *              XChaCha works by XORing plaintext with a keystream, so
 458  *              encryption and decryption are the same operation.  If @dest@
 459  *              is null then ignore @src@ and skip @sz@ bytes of the
 460  *              keystream.  If @src@ is null, then just write the keystream
 461  *              to @dest@.
 462  */
 463
 464 #define DEFXPASSTHRU(r)                                                 \
 465   void XCHACHA_SEEK(r, XCHACHA_CTX(r) *ctx, unsigned long i)            \
 466     { chacha_seek(&ctx->s, i); }                                        \
 467   void XCHACHA_SEEKU64(r, XCHACHA_CTX(r) *ctx, kludge64 i)              \
 468     { chacha_seeku64(&ctx->s, i); }                                     \
 469   unsigned long XCHACHA_TELL(r, XCHACHA_CTX(r) *ctx)                    \
 470     { return chacha_tell(&ctx->s); }                                    \
 471   kludge64 XCHACHA_TELLU64(r, XCHACHA_CTX(r) *ctx)                      \
 472     { return chacha_tellu64(&ctx->s); }                                 \
 473   void XCHACHA_ENCRYPT(r, XCHACHA_CTX(r) *ctx,                          \
 474                         const void *src, void *dest, size_t sz)         \
 475     { CHACHA_ENCRYPT(r, &ctx->s, src, dest, sz); }
 476 CHACHA_VARS(DEFXPASSTHRU)
 477
 478 /*----- Generic cipher interface ------------------------------------------*/
 479
 480 typedef struct gctx { gcipher c; chacha_ctx ctx; } gctx;
 481
 482 static void gsetiv(gcipher *c, const void *iv)
 483   { gctx *g = (gctx *)c; chacha_setnonce(&g->ctx, iv); }
 484
 485 static void gdestroy(gcipher *c)
 486   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 487
 488 #define DEFGCIPHER(r)                                                   \
 489                                                                         \
 490   static const gcipher_ops gops_##r;                                    \
 491                                                                         \
 492   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 493   {                                                                     \
 494     gctx *g = S_CREATE(gctx);                                           \
 495     g->c.ops = &gops_##r;                                               \
 496     chacha_init(&g->ctx, k, sz, 0);                                     \
 497     return (&g->c);                                                     \
 498   }                                                                     \
 499                                                                         \
 500   static void gencrypt_##r(gcipher *c, const void *s,                   \
 501                            void *t, size_t sz)                          \
 502     { gctx *g = (gctx *)c; CHACHA_ENCRYPT(r, &g->ctx, s, t, sz); }      \
 503                                                                         \
 504   static const gcipher_ops gops_##r = {                                 \
 505     &chacha##r,                                                         \
 506     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 507   };                                                                    \
 508                                                                         \
 509   const gccipher chacha##r = {                                          \
 510     "chacha" #r, chacha_keysz,                                          \
 511     CHACHA_NONCESZ, ginit_##r                                           \
 512   };
 513
 514 CHACHA_VARS(DEFGCIPHER)
 515
 516 #define DEFGXCIPHER(r)                                                  \
 517                                                                         \
 518   typedef struct { gcipher c; XCHACHA_CTX(r) ctx; } gxctx_##r;          \
 519                                                                         \
 520   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 521     { gxctx_##r *g = (gxctx_##r *)c; XCHACHA_SETNONCE(r, &g->ctx, iv); } \
 522                                                                         \
 523   static void gxdestroy_##r(gcipher *c)                                 \
 524     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 525                                                                         \
 526   static const gcipher_ops gxops_##r;                                   \
 527                                                                         \
 528   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 529   {                                                                     \
 530     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 531     g->c.ops = &gxops_##r;                                              \
 532     XCHACHA_INIT(r, &g->ctx, k, sz, 0);                                 \
 533     return (&g->c);                                                     \
 534   }                                                                     \
 535                                                                         \
 536   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 537                             void *t, size_t sz)                         \
 538   {                                                                     \
 539     gxctx_##r *g = (gxctx_##r *)c;                                      \
 540     XCHACHA_ENCRYPT(r, &g->ctx, s, t, sz);                              \
 541   }                                                                     \
 542                                                                         \
 543   static const gcipher_ops gxops_##r = {                                \
 544     &xchacha##r,                                                        \
 545     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 546   };                                                                    \
 547                                                                         \
 548   const gccipher xchacha##r = {                                         \
 549     "xchacha" #r, chacha_keysz,                                         \
 550     CHACHA_NONCESZ, gxinit_##r                                          \
 551   };
 552
 553 CHACHA_VARS(DEFGXCIPHER)
 554
 555 /*----- Generic random number generator interface -------------------------*/
 556
 557 typedef struct grops {
 558   size_t noncesz;
 559   void (*seek)(void *, kludge64);
 560   kludge64 (*tell)(void *);
 561   void (*setnonce)(void *, const void *);
 562   void (*generate)(void *, void *, size_t);
 563 } grops;
 564
 565 typedef struct grbasectx {
 566   grand r;
 567   const grops *ops;
 568 } grbasectx;
 569
 570 static int grmisc(grand *r, unsigned op, ...)
 571 {
 572   octet buf[XCHACHA_NONCESZ];
 573   grbasectx *g = (grbasectx *)r;
 574   grand *rr;
 575   const octet *p;
 576   size_t sz;
 577   uint32 i;
 578   unsigned long ul;
 579   kludge64 pos;
 580   va_list ap;
 581   int rc = 0;
 582
 583   va_start(ap, op);
 584
 585   switch (op) {
 586     case GRAND_CHECK:
 587       switch (va_arg(ap, unsigned)) {
 588         case GRAND_CHECK:
 589         case GRAND_SEEDINT:
 590         case GRAND_SEEDUINT32:
 591         case GRAND_SEEDBLOCK:
 592         case GRAND_SEEDRAND:
 593         case CHACHA_SEEK:
 594         case CHACHA_SEEKU64:
 595         case CHACHA_TELL:
 596         case CHACHA_TELLU64:
 597           rc = 1;
 598           break;
 599         default:
 600           rc = 0;
 601           break;
 602       }
 603       break;
 604
 605     case GRAND_SEEDINT:
 606       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 607       memset(buf + 4, 0, g->ops->noncesz - 4);
 608       g->ops->setnonce(g, buf);
 609       break;
 610     case GRAND_SEEDUINT32:
 611       i = va_arg(ap, uint32); STORE32_L(buf, i);
 612       memset(buf + 4, 0, g->ops->noncesz - 4);
 613       g->ops->setnonce(g, buf);
 614       break;
 615     case GRAND_SEEDBLOCK:
 616       p = va_arg(ap, const void *);
 617       sz = va_arg(ap, size_t);
 618       if (sz < g->ops->noncesz) {
 619         memcpy(buf, p, sz);
 620         memset(buf + sz, 0, g->ops->noncesz - sz);
 621         p = buf;
 622       }
 623       g->ops->setnonce(g, p);
 624       break;
 625     case GRAND_SEEDRAND:
 626       rr = va_arg(ap, grand *);
 627       rr->ops->fill(rr, buf, g->ops->noncesz);
 628       g->ops->setnonce(g, buf);
 629       break;
 630     case CHACHA_SEEK:
 631       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 632       g->ops->seek(g, pos);
 633       break;
 634     case CHACHA_SEEKU64:
 635       pos = va_arg(ap, kludge64);
 636       g->ops->seek(g, pos);
 637       break;
 638     case CHACHA_TELL:
 639       pos = g->ops->tell(g);
 640       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 641       break;
 642     case CHACHA_TELLU64:
 643       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 644       break;
 645     default:
 646       GRAND_BADOP;
 647       break;
 648   }
 649
 650   return (rc);
 651 }
 652
 653 static octet grbyte(grand *r)
 654 {
 655   grbasectx *g = (grbasectx *)r;
 656   octet o;
 657   g->ops->generate(g, &o, 1);
 658   return (o);
 659 }
 660
 661 static uint32 grword(grand *r)
 662 {
 663   grbasectx *g = (grbasectx *)r;
 664   octet b[4];
 665   g->ops->generate(g, b, sizeof(b));
 666   return (LOAD32_L(b));
 667 }
 668
 669 static void grfill(grand *r, void *p, size_t sz)
 670 {
 671   grbasectx *g = (grbasectx *)r;
 672   g->ops->generate(r, p, sz);
 673 }
 674
 675 typedef struct grctx {
 676   grbasectx r;
 677   chacha_ctx ctx;
 678 } grctx;
 679
 680 static void gr_seek(void *r, kludge64 pos)
 681   { grctx *g = r; chacha_seeku64(&g->ctx, pos); }
 682
 683 static kludge64 gr_tell(void *r)
 684   { grctx *g = r; return (chacha_tellu64(&g->ctx)); }
 685
 686 static void gr_setnonce(void *r, const void *n)
 687   { grctx *g = r; chacha_setnonce(&g->ctx, n); }
 688
 689 static void grdestroy(grand *r)
 690   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 691
 692 #define DEFGRAND(rr)                                                    \
 693                                                                         \
 694   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 695     { grctx *g = r; CHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }            \
 696                                                                         \
 697   static const grops grops_##rr =                                       \
 698     { CHACHA_NONCESZ, gr_seek, gr_tell,                                 \
 699       gr_setnonce, gr_generate_##rr };                                  \
 700                                                                         \
 701   static const grand_ops grops_rand_##rr = {                            \
 702     "chacha" #rr, GRAND_CRYPTO, 0,                                      \
 703     grmisc, grdestroy, grword,                                          \
 704     grbyte, grword, grand_defaultrange, grfill                          \
 705   };                                                                    \
 706                                                                         \
 707   grand *chacha##rr##_rand(const void *k, size_t ksz, const void *n)    \
 708   {                                                                     \
 709     grctx *g = S_CREATE(grctx);                                         \
 710     g->r.r.ops = &grops_rand_##rr;                                      \
 711     g->r.ops = &grops_##rr;                                             \
 712     chacha_init(&g->ctx, k, ksz, n);                                    \
 713     return (&g->r.r);                                                   \
 714   }
 715 CHACHA_VARS(DEFGRAND)
 716
 717 #define DEFXGRAND(rr)                                                   \
 718                                                                         \
 719   typedef struct grxctx_##rr {                                          \
 720     grbasectx r;                                                        \
 721     XCHACHA_CTX(rr) ctx;                                                \
 722   } grxctx_##rr;                                                        \
 723                                                                         \
 724   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 725     { grxctx_##rr *g = r; XCHACHA_SEEKU64(rr, &g->ctx, pos); }          \
 726                                                                         \
 727   static kludge64 grx_tell_##rr(void *r)                                \
 728     { grxctx_##rr *g = r; return (XCHACHA_TELLU64(rr, &g->ctx)); }      \
 729                                                                         \
 730   static void grx_setnonce_##rr(void *r, const void *n)                 \
 731     { grxctx_##rr *g = r; XCHACHA_SETNONCE(rr, &g->ctx, n); }           \
 732                                                                         \
 733   static void grxdestroy_##rr(grand *r)                                 \
 734     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 735                                                                         \
 736   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 737     { grxctx_##rr *g = r; XCHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }     \
 738                                                                         \
 739   static const grops grxops_##rr =                                      \
 740     { XCHACHA_NONCESZ, grx_seek_##rr, grx_tell_##rr,                    \
 741       grx_setnonce_##rr, grx_generate_##rr };                           \
 742                                                                         \
 743   static const grand_ops grxops_rand_##rr = {                           \
 744     "xchacha" #rr, GRAND_CRYPTO, 0,                                     \
 745     grmisc, grxdestroy_##rr, grword,                                    \
 746     grbyte, grword, grand_defaultrange, grfill                          \
 747   };                                                                    \
 748                                                                         \
 749   grand *xchacha##rr##_rand(const void *k, size_t ksz, const void *n)   \
 750   {                                                                     \
 751     grxctx_##rr *g = S_CREATE(grxctx_##rr);                             \
 752     g->r.r.ops = &grxops_rand_##rr;                                     \
 753     g->r.ops = &grxops_##rr;                                            \
 754     XCHACHA_INIT(rr, &g->ctx, k, ksz, n);                               \
 755     return (&g->r.r);                                                   \
 756   }
 757 CHACHA_VARS(DEFXGRAND)
 758
 759 /*----- Test rig ----------------------------------------------------------*/
 760
 761 #ifdef TEST_RIG
 762
 763 #include <stdio.h>
 764 #include <string.h>
 765
 766 #include <mLib/quis.h>
 767 #include <mLib/testrig.h>
 768
 769 #define DEFVCORE(r)                                                     \
 770   static int v_core_##r(dstr *v)                                        \
 771   {                                                                     \
 772     chacha_matrix a, b;                                                 \
 773     dstr d = DSTR_INIT;                                                 \
 774     int i, n;                                                           \
 775     int ok = 1;                                                         \
 776                                                                         \
 777     DENSURE(&d, CHACHA_OUTSZ); d.len = CHACHA_OUTSZ;                    \
 778     n = *(int *)v[0].buf;                                               \
 779     for (i = 0; i < CHACHA_OUTSZ/4; i++)                                \
 780       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 781     for (i = 0; i < n; i++) {                                           \
 782       core(r, a, b);                                                    \
 783       memcpy(a, b, sizeof(a));                                          \
 784     }                                                                   \
 785     for (i = 0; i < CHACHA_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]);  \
 786                                                                         \
 787     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 788       ok = 0;                                                           \
 789       printf("\nfail core:"                                             \
 790              "\n\titerations = %d"                                      \
 791              "\n\tin       = ", n);                                     \
 792       type_hex.dump(&v[1], stdout);                                     \
 793       printf("\n\texpected   = ");                                      \
 794       type_hex.dump(&v[2], stdout);                                     \
 795       printf("\n\tcalculated = ");                                      \
 796       type_hex.dump(&d, stdout);                                        \
 797       putchar('\n');                                                    \
 798     }                                                                   \
 799                                                                         \
 800     dstr_destroy(&d);                                                   \
 801     return (ok);                                                        \
 802   }
 803 CHACHA_VARS(DEFVCORE)
 804
 805 #define CHACHA_CTX(r) chacha_ctx
 806 #define CHACHA_INIT(r, ctx, k, ksz, n) chacha_init(ctx, k, ksz, n)
 807 #define CHACHA_SEEKU64(r, ctx, i) chacha_seeku64(ctx, i)
 808 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 809
 810 #define DEFxVENC(base, BASE, r)                                         \
 811   static int v_encrypt_##base##_##r(dstr *v)                            \
 812   {                                                                     \
 813     BASE##_CTX(r) ctx;                                                  \
 814     dstr d = DSTR_INIT;                                                 \
 815     kludge64 pos;                                                       \
 816     const octet *p, *p0;                                                \
 817     octet *q;                                                           \
 818     size_t sz, sz0, step;                                               \
 819     unsigned long skip;                                                 \
 820     int ok = 1;                                                         \
 821                                                                         \
 822     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 823     else { p0 = 0; sz0 = v[5].len; }                                    \
 824     DENSURE(&d, sz0); d.len = sz0;                                      \
 825     skip = *(unsigned long *)v[3].buf;                                  \
 826                                                                         \
 827     step = 0;                                                           \
 828     while (step < sz0 + skip) {                                         \
 829       step = step ? 3*step + 4 : 1;                                     \
 830       if (step > sz0 + skip) step = sz0 + skip;                         \
 831       BASE##_INIT(r, &ctx, v[0].buf, v[0].len, v[1].buf);               \
 832       if (v[2].len) {                                                   \
 833         LOAD64_(pos, v[2].buf);                                         \
 834         BASE##_SEEKU64(r, &ctx, pos);                                   \
 835       }                                                                 \
 836                                                                         \
 837       for (sz = skip; sz >= step; sz -= step)                           \
 838         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 839       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 840       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 841            sz >= step;                                                  \
 842            sz -= step, q += step) {                                     \
 843         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 844         if (p) p += step;                                               \
 845       }                                                                 \
 846       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 847                                                                         \
 848       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 849         ok = 0;                                                         \
 850         printf("\nfail encrypt:"                                        \
 851                "\n\tstep           = %lu"                               \
 852                "\n\tkey    = ", (unsigned long)step);                   \
 853         type_hex.dump(&v[0], stdout);                                   \
 854         printf("\n\tnonce          = ");                                \
 855         type_hex.dump(&v[1], stdout);                                   \
 856         printf("\n\tposition   = ");                                    \
 857         type_hex.dump(&v[2], stdout);                                   \
 858         printf("\n\tskip           = %lu", skip);                       \
 859         printf("\n\tmessage    = ");                                    \
 860         type_hex.dump(&v[4], stdout);                                   \
 861         printf("\n\texpected   = ");                                    \
 862         type_hex.dump(&v[5], stdout);                                   \
 863         printf("\n\tcalculated = ");                                    \
 864         type_hex.dump(&d, stdout);                                      \
 865         putchar('\n');                                                  \
 866       }                                                                 \
 867     }                                                                   \
 868                                                                         \
 869     dstr_destroy(&d);                                                   \
 870     return (ok);                                                        \
 871   }
 872 #define DEFVENC(r) DEFxVENC(chacha, CHACHA, r)
 873 #define DEFXVENC(r) DEFxVENC(xchacha, XCHACHA, r)
 874 CHACHA_VARS(DEFVENC)
 875 CHACHA_VARS(DEFXVENC)
 876
 877 static test_chunk defs[] = {
 878 #define DEFxTAB(base, r)                                                \
 879   { #base #r, v_encrypt_##base##_##r,                                   \
 880     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 881       &type_hex, &type_hex, 0 } },
 882 #define DEFTAB(r)                                                       \
 883   { "chacha" #r "-core", v_core_##r,                                    \
 884     { &type_int, &type_hex, &type_hex, 0 } },                           \
 885   DEFxTAB(chacha, r)
 886 #define DEFXTAB(r) DEFxTAB(xchacha, r)
 887 CHACHA_VARS(DEFTAB)
 888 CHACHA_VARS(DEFXTAB)
 889   { 0, 0, { 0 } }
 890 };
 891
 892 int main(int argc, char *argv[])
 893 {
 894   test_run(argc, argv, defs, SRCDIR"/t/chacha");
 895   return (0);
 896 }
 897
 898 #endif
 899
 900 /*----- That's all, folks -------------------------------------------------*/