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),
  66              void, core, (unsigned r, const chacha_matrix src,
  67                           chacha_matrix dest),
  68              (r, src, dest),
  69              pick_core, simple_core);
  70
  71 static void simple_core(unsigned r, const chacha_matrix src,
  72                         chacha_matrix dest)
  73   { CHACHA_nR(dest, src, r); CHACHA_FFWD(dest, src); }
  74
  75 #if CPUFAM_X86 || CPUFAM_AMD64
  76 extern core__functype chacha_core_x86ish_sse2;
  77 #endif
  78
  79 #if CPUFAM_ARMEL
  80 extern core__functype chacha_core_arm_neon;
  81 #endif
  82
  83 static core__functype *pick_core(void)
  84 {
  85 #if CPUFAM_X86 || CPUFAM_AMD64
  86   DISPATCH_PICK_COND(chacha_core, chacha_core_x86ish_sse2,
  87                      cpu_feature_p(CPUFEAT_X86_SSE2));
  88 #endif
  89 #if CPUFAM_ARMEL
  90   DISPATCH_PICK_COND(chacha_core, chacha_core_arm_neon,
  91                      cpu_feature_p(CPUFEAT_ARM_NEON));
  92 #endif
  93   DISPATCH_PICK_FALLBACK(chacha_core, simple_core);
  94 }
  95
  96 /* --- @populate@ --- *
  97  *
  98  * Arguments:   @chacha_matrix a@ = a matrix to fill in
  99  *              @const void *key@ = pointer to key material
 100  *              @size_t ksz@ = size of key
 101  *
 102  * Returns:     ---
 103  *
 104  * Use:         Fills in a ChaCha matrix from the key, setting the
 105  *              appropriate constants according to the key length.  The nonce
 106  *              and position words are left uninitialized.
 107  */
 108
 109 static void populate(chacha_matrix a, const void *key, size_t ksz)
 110 {
 111   const octet *k = key;
 112
 113   KSZ_ASSERT(chacha, ksz);
 114
 115   a[ 4] = LOAD32_L(k +  0);
 116   a[ 5] = LOAD32_L(k +  4);
 117   if (ksz == 10) {
 118     a[ 6] = LOAD16_L(k +  8);
 119     a[ 7] = 0;
 120   } else {
 121     a[ 6] = LOAD32_L(k +  8);
 122     a[ 7] = LOAD32_L(k + 12);
 123   }
 124   if (ksz <= 16) {
 125     a[ 8] = a[ 4];
 126     a[ 9] = a[ 5];
 127     a[10] = a[ 6];
 128     a[11] = a[ 7];
 129     a[ 0] = CHACHA_A128;
 130     a[ 1] = CHACHA_B128;
 131     a[ 2] = ksz == 10 ? CHACHA_C80 : CHACHA_C128;
 132     a[ 3] = CHACHA_D128;
 133   } else {
 134     a[ 8] = LOAD32_L(k + 16);
 135     a[ 9] = LOAD32_L(k + 20);
 136     a[10] = LOAD32_L(k + 24);
 137     a[11] = LOAD32_L(k + 28);
 138     a[ 0] = CHACHA_A256;
 139     a[ 1] = CHACHA_B256;
 140     a[ 2] = CHACHA_C256;
 141     a[ 3] = CHACHA_D256;
 142   }
 143 }
 144
 145 /*----- ChaCha implementation ---------------------------------------------*/
 146
 147 /* --- @chacha_init@ --- *
 148  *
 149  * Arguments:   @chacha_ctx *ctx@ = context to fill in
 150  *              @const void *key@ = pointer to key material
 151  *              @size_t ksz@ = size of key (either 32 or 16)
 152  *              @const void *nonce@ = initial nonce, or null
 153  *
 154  * Returns:     ---
 155  *
 156  * Use:         Initializes a ChaCha context ready for use.
 157  */
 158
 159 void chacha_init(chacha_ctx *ctx, const void *key, size_t ksz,
 160                   const void *nonce)
 161 {
 162   static const octet zerononce[CHACHA_NONCESZ];
 163
 164   populate(ctx->a, key, ksz);
 165   chacha_setnonce(ctx, nonce ? nonce : zerononce);
 166 }
 167
 168 /* --- @chacha_setnonce@ --- *
 169  *
 170  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 171  *              @const void *nonce@ = the nonce (@CHACHA_NONCESZ@ bytes)
 172  *
 173  * Returns:     ---
 174  *
 175  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 176  *              different message.  The stream position is reset to zero (see
 177  *              @chacha_seek@ etc.).
 178  */
 179
 180 void chacha_setnonce(chacha_ctx *ctx, const void *nonce)
 181 {
 182   const octet *n = nonce;
 183
 184   ctx->a[14] = LOAD32_L(n + 0);
 185   ctx->a[15] = LOAD32_L(n + 4);
 186   chacha_seek(ctx, 0);
 187 }
 188
 189 /* --- @chacha_seek@, @chacha_seeku64@ --- *
 190  *
 191  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 192  *              @unsigned long i@, @kludge64 i@ = new position to set
 193  *
 194  * Returns:     ---
 195  *
 196  * Use:         Sets a new stream position, in units of Chacha output
 197  *              blocks, which are @CHACHA_OUTSZ@ bytes each.  Byte
 198  *              granularity can be achieved by calling @chachaR_encrypt@
 199  *              appropriately.
 200  */
 201
 202 void chacha_seek(chacha_ctx *ctx, unsigned long i)
 203   { kludge64 ii; ASSIGN64(ii, i); chacha_seeku64(ctx, ii); }
 204
 205 void chacha_seeku64(chacha_ctx *ctx, kludge64 i)
 206 {
 207   ctx->a[12] = LO64(i); ctx->a[13] = HI64(i);
 208   ctx->bufi = CHACHA_OUTSZ;
 209 }
 210
 211 /* --- @chacha_tell@, @chacha_tellu64@ --- *
 212  *
 213  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 214  *
 215  * Returns:     The current position in the output stream, in blocks,
 216  *              rounding upwards.
 217  */
 218
 219 unsigned long chacha_tell(chacha_ctx *ctx)
 220   { kludge64 i = chacha_tellu64(ctx); return (GET64(unsigned long, i)); }
 221
 222 kludge64 chacha_tellu64(chacha_ctx *ctx)
 223   { kludge64 i; SET64(i, ctx->a[9], ctx->a[8]); return (i); }
 224
 225 /* --- @chacha{,12,8}_encrypt@ --- *
 226  *
 227  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 228  *              @const void *src@ = source buffer (or null)
 229  *              @void *dest@ = destination buffer (or null)
 230  *              @size_t sz@ = size of the buffers
 231  *
 232  * Returns:     ---
 233  *
 234  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 235  *              ChaCha works by XORing plaintext with a keystream, so
 236  *              encryption and decryption are the same operation.  If @dest@
 237  *              is null then ignore @src@ and skip @sz@ bytes of the
 238  *              keystream.  If @src@ is null, then just write the keystream
 239  *              to @dest@.
 240  */
 241
 242 #define CHACHA_ENCRYPT(r, ctx, src, dest, sz)                           \
 243   chacha##r##_encrypt(ctx, src, dest, sz)
 244 #define DEFENCRYPT(r)                                                   \
 245   void CHACHA_ENCRYPT(r, chacha_ctx *ctx, const void *src,              \
 246                       void *dest, size_t sz)                            \
 247   {                                                                     \
 248     chacha_matrix b;                                                    \
 249     const octet *s = src;                                               \
 250     octet *d = dest;                                                    \
 251     size_t n;                                                           \
 252     kludge64 pos, delta;                                                \
 253                                                                         \
 254     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 255     if (!sz) return;                                                    \
 256                                                                         \
 257     if (!dest) {                                                        \
 258       n = sz/CHACHA_OUTSZ;                                              \
 259       pos = chacha_tellu64(ctx);                                        \
 260       ASSIGN64(delta, n);                                               \
 261       ADD64(pos, pos, delta);                                           \
 262       chacha_seeku64(ctx, pos);                                         \
 263       sz = sz%CHACHA_OUTSZ;                                             \
 264     } else if (!src) {                                                  \
 265       while (sz >= CHACHA_OUTSZ) {                                      \
 266         core(r, ctx->a, b);                                             \
 267         CHACHA_STEP(ctx->a);                                            \
 268         SALSA20_GENFULL(b, d);                                          \
 269         sz -= CHACHA_OUTSZ;                                             \
 270       }                                                                 \
 271     } else {                                                            \
 272       while (sz >= CHACHA_OUTSZ) {                                      \
 273         core(r, ctx->a, b);                                             \
 274         CHACHA_STEP(ctx->a);                                            \
 275         SALSA20_MIXFULL(b, d, s);                                       \
 276         sz -= CHACHA_OUTSZ;                                             \
 277       }                                                                 \
 278     }                                                                   \
 279                                                                         \
 280     if (sz) {                                                           \
 281       core(r, ctx->a, b);                                               \
 282       CHACHA_STEP(ctx->a);                                              \
 283       SALSA20_PREPBUF(ctx, b);                                          \
 284       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 285       assert(!sz);                                                      \
 286     }                                                                   \
 287   }
 288 CHACHA_VARS(DEFENCRYPT)
 289
 290 /*----- HChaCha implementation --------------------------------------------*/
 291
 292 #define HCHACHA_RAW(r, ctx, src, dest) hchacha##r##_raw(ctx, src, dest)
 293 #define HCHACHA_PRF(r, ctx, src, dest) hchacha##r##_prf(ctx, src, dest)
 294
 295 /* --- @hchacha{20,12,8}_prf@ --- *
 296  *
 297  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 298  *              @const void *src@ = the input (@HCHACHA_INSZ@ bytes)
 299  *              @void *dest@ = the output (@HCHACHA_OUTSZ@ bytes)
 300  *
 301  * Returns:     ---
 302  *
 303  * Use:         Apply the HChacha/r pseudorandom function to @src@, writing
 304  *              the result to @out@.
 305  */
 306
 307 #define DEFHCHACHA(r)                                                   \
 308   static void HCHACHA_RAW(r, chacha_matrix k,                           \
 309                           const uint32 *src, uint32 *dest)              \
 310   {                                                                     \
 311     chacha_matrix a;                                                    \
 312     int i;                                                              \
 313                                                                         \
 314     /* --- HChaCha, computed from full ChaCha --- *                     \
 315      *                                                                  \
 316      * The security proof makes use of the fact that HChaCha (i.e.,     \
 317      * without the final feedforward step) can be computed from full    \
 318      * ChaCha using only knowledge of the non-secret input.  I don't    \
 319      * want to compromise the performance of the main function by       \
 320      * making the feedforward step separate, but this operation is less \
 321      * speed critical, so we do it the harder way.                      \
 322      */                                                                 \
 323                                                                         \
 324     for (i = 0; i < 4; i++) k[12 + i] = src[i];                         \
 325     core(r, k, a);                                                      \
 326     for (i = 0; i < 8; i++) dest[i] = a[(i + 4)^4] - k[(i + 4)^4];      \
 327   }                                                                     \
 328                                                                         \
 329   void HCHACHA_PRF(r, chacha_ctx *ctx, const void *src, void *dest)     \
 330   {                                                                     \
 331     const octet *s = src;                                               \
 332     octet *d = dest;                                                    \
 333     uint32 in[4], out[8];                                               \
 334     int i;                                                              \
 335                                                                         \
 336     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 337     HCHACHA_RAW(r, ctx->a, in, out);                                    \
 338     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 339   }
 340 CHACHA_VARS(DEFHCHACHA)
 341
 342 /*----- XChaCha implementation -------------------------------------------*/
 343
 344 /* --- Some convenient macros for naming functions --- *
 345  *
 346  * Because the crypto core is involved in XChaCha/r's per-nonce setup, we
 347  * need to take an interest in the number of rounds in most of the various
 348  * functions, and it will probably help if we distinguish the context
 349  * structures for the various versions.
 350  */
 351
 352 #define XCHACHA_CTX(r) xchacha##r##_ctx
 353 #define XCHACHA_INIT(r, ctx, k, ksz, n) xchacha##r##_init(ctx, k, ksz, n)
 354 #define XCHACHA_SETNONCE(r, ctx, n) xchacha##r##_setnonce(ctx, n)
 355 #define XCHACHA_SEEK(r, ctx, i) xchacha##r##_seek(ctx, i)
 356 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 357 #define XCHACHA_TELL(r, ctx) xchacha##r##_tell(ctx)
 358 #define XCHACHA_TELLU64(r, ctx) xchacha##r##_tellu64(ctx)
 359 #define XCHACHA_ENCRYPT(r, ctx, src, dest, sz)                          \
 360   xchacha##r##_encrypt(ctx, src, dest, sz)
 361
 362 /* --- @xchacha{20,12,8}_init@ --- *
 363  *
 364  * Arguments:   @xchachaR_ctx *ctx@ = the context to fill in
 365  *              @const void *key@ = pointer to key material
 366  *              @size_t ksz@ = size of key (either 32 or 16)
 367  *              @const void *nonce@ = initial nonce, or null
 368  *
 369  * Returns:     ---
 370  *
 371  * Use:         Initializes an XChaCha/r context ready for use.
 372  *
 373  *              There is a different function for each number of rounds,
 374  *              unlike for plain ChaCha.
 375  */
 376
 377 #define DEFXINIT(r)                                                     \
 378   void XCHACHA_INIT(r, XCHACHA_CTX(r) *ctx,                             \
 379                     const void *key, size_t ksz, const void *nonce)     \
 380   {                                                                     \
 381     static const octet zerononce[XCHACHA_NONCESZ];                      \
 382                                                                         \
 383     populate(ctx->k, key, ksz);                                         \
 384     ctx->s.a[ 0] = CHACHA_A256;                                         \
 385     ctx->s.a[ 1] = CHACHA_B256;                                         \
 386     ctx->s.a[ 2] = CHACHA_C256;                                         \
 387     ctx->s.a[ 3] = CHACHA_D256;                                         \
 388     XCHACHA_SETNONCE(r, ctx, nonce ? nonce : zerononce);                \
 389   }
 390 CHACHA_VARS(DEFXINIT)
 391
 392 /* --- @xchacha{20,12,8}_setnonce@ --- *
 393  *
 394  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 395  *              @const void *nonce@ = the nonce (@XCHACHA_NONCESZ@ bytes)
 396  *
 397  * Returns:     ---
 398  *
 399  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 400  *              different message.  The stream position is reset to zero (see
 401  *              @chacha_seek@ etc.).
 402  *
 403  *              There is a different function for each number of rounds,
 404  *              unlike for plain ChaCha.
 405  */
 406
 407 #define DEFXNONCE(r)                                                    \
 408   void XCHACHA_SETNONCE(r, XCHACHA_CTX(r) *ctx, const void *nonce)      \
 409   {                                                                     \
 410     const octet *n = nonce;                                             \
 411     uint32 in[4];                                                       \
 412     int i;                                                              \
 413                                                                         \
 414     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 415     HCHACHA_RAW(r, ctx->k, in, ctx->s.a + 4);                           \
 416     chacha_setnonce(&ctx->s, n + 16);                                   \
 417   }
 418 CHACHA_VARS(DEFXNONCE)
 419
 420 /* --- @xchacha{20,12,8}_seek@, @xchacha{20,12,8}_seeku64@ --- *
 421  *
 422  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 423  *              @unsigned long i@, @kludge64 i@ = new position to set
 424  *
 425  * Returns:     ---
 426  *
 427  * Use:         Sets a new stream position, in units of ChaCha output
 428  *              blocks, which are @XCHACHA_OUTSZ@ bytes each.  Byte
 429  *              granularity can be achieved by calling @xchachaR_encrypt@
 430  *              appropriately.
 431  *
 432  *              There is a different function for each number of rounds,
 433  *              unlike for plain ChaCha, because the context structures are
 434  *              different.
 435  */
 436
 437 /* --- @xchacha{20,12,8}_tell@, @xchacha{20,12,8}_tellu64@ --- *
 438  *
 439  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 440  *
 441  * Returns:     The current position in the output stream, in blocks,
 442  *              rounding upwards.
 443  *
 444  *              There is a different function for each number of rounds,
 445  *              unlike for plain ChaCha, because the context structures are
 446  *              different.
 447  */
 448
 449 /* --- @xchacha{,12,8}_encrypt@ --- *
 450  *
 451  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 452  *              @const void *src@ = source buffer (or null)
 453  *              @void *dest@ = destination buffer (or null)
 454  *              @size_t sz@ = size of the buffers
 455  *
 456  * Returns:     ---
 457  *
 458  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 459  *              XChaCha works by XORing plaintext with a keystream, so
 460  *              encryption and decryption are the same operation.  If @dest@
 461  *              is null then ignore @src@ and skip @sz@ bytes of the
 462  *              keystream.  If @src@ is null, then just write the keystream
 463  *              to @dest@.
 464  */
 465
 466 #define DEFXPASSTHRU(r)                                                 \
 467   void XCHACHA_SEEK(r, XCHACHA_CTX(r) *ctx, unsigned long i)            \
 468     { chacha_seek(&ctx->s, i); }                                        \
 469   void XCHACHA_SEEKU64(r, XCHACHA_CTX(r) *ctx, kludge64 i)              \
 470     { chacha_seeku64(&ctx->s, i); }                                     \
 471   unsigned long XCHACHA_TELL(r, XCHACHA_CTX(r) *ctx)                    \
 472     { return chacha_tell(&ctx->s); }                                    \
 473   kludge64 XCHACHA_TELLU64(r, XCHACHA_CTX(r) *ctx)                      \
 474     { return chacha_tellu64(&ctx->s); }                                 \
 475   void XCHACHA_ENCRYPT(r, XCHACHA_CTX(r) *ctx,                          \
 476                         const void *src, void *dest, size_t sz)         \
 477     { CHACHA_ENCRYPT(r, &ctx->s, src, dest, sz); }
 478 CHACHA_VARS(DEFXPASSTHRU)
 479
 480 /*----- Generic cipher interface ------------------------------------------*/
 481
 482 typedef struct gctx { gcipher c; chacha_ctx ctx; } gctx;
 483
 484 static void gsetiv(gcipher *c, const void *iv)
 485   { gctx *g = (gctx *)c; chacha_setnonce(&g->ctx, iv); }
 486
 487 static void gdestroy(gcipher *c)
 488   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 489
 490 #define DEFGCIPHER(r)                                                   \
 491                                                                         \
 492   static const gcipher_ops gops_##r;                                    \
 493                                                                         \
 494   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 495   {                                                                     \
 496     gctx *g = S_CREATE(gctx);                                           \
 497     g->c.ops = &gops_##r;                                               \
 498     chacha_init(&g->ctx, k, sz, 0);                                     \
 499     return (&g->c);                                                     \
 500   }                                                                     \
 501                                                                         \
 502   static void gencrypt_##r(gcipher *c, const void *s,                   \
 503                            void *t, size_t sz)                          \
 504     { gctx *g = (gctx *)c; CHACHA_ENCRYPT(r, &g->ctx, s, t, sz); }      \
 505                                                                         \
 506   static const gcipher_ops gops_##r = {                                 \
 507     &chacha##r,                                                         \
 508     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 509   };                                                                    \
 510                                                                         \
 511   const gccipher chacha##r = {                                          \
 512     "chacha" #r, chacha_keysz,                                          \
 513     CHACHA_NONCESZ, ginit_##r                                           \
 514   };
 515
 516 CHACHA_VARS(DEFGCIPHER)
 517
 518 #define DEFGXCIPHER(r)                                                  \
 519                                                                         \
 520   typedef struct { gcipher c; XCHACHA_CTX(r) ctx; } gxctx_##r;          \
 521                                                                         \
 522   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 523     { gxctx_##r *g = (gxctx_##r *)c; XCHACHA_SETNONCE(r, &g->ctx, iv); } \
 524                                                                         \
 525   static void gxdestroy_##r(gcipher *c)                                 \
 526     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 527                                                                         \
 528   static const gcipher_ops gxops_##r;                                   \
 529                                                                         \
 530   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 531   {                                                                     \
 532     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 533     g->c.ops = &gxops_##r;                                              \
 534     XCHACHA_INIT(r, &g->ctx, k, sz, 0);                                 \
 535     return (&g->c);                                                     \
 536   }                                                                     \
 537                                                                         \
 538   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 539                             void *t, size_t sz)                         \
 540   {                                                                     \
 541     gxctx_##r *g = (gxctx_##r *)c;                                      \
 542     XCHACHA_ENCRYPT(r, &g->ctx, s, t, sz);                              \
 543   }                                                                     \
 544                                                                         \
 545   static const gcipher_ops gxops_##r = {                                \
 546     &xchacha##r,                                                        \
 547     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 548   };                                                                    \
 549                                                                         \
 550   const gccipher xchacha##r = {                                         \
 551     "xchacha" #r, chacha_keysz,                                         \
 552     CHACHA_NONCESZ, gxinit_##r                                          \
 553   };
 554
 555 CHACHA_VARS(DEFGXCIPHER)
 556
 557 /*----- Generic random number generator interface -------------------------*/
 558
 559 typedef struct grops {
 560   size_t noncesz;
 561   void (*seek)(void *, kludge64);
 562   kludge64 (*tell)(void *);
 563   void (*setnonce)(void *, const void *);
 564   void (*generate)(void *, void *, size_t);
 565 } grops;
 566
 567 typedef struct grbasectx {
 568   grand r;
 569   const grops *ops;
 570 } grbasectx;
 571
 572 static int grmisc(grand *r, unsigned op, ...)
 573 {
 574   octet buf[XCHACHA_NONCESZ];
 575   grbasectx *g = (grbasectx *)r;
 576   grand *rr;
 577   const octet *p;
 578   size_t sz;
 579   uint32 i;
 580   unsigned long ul;
 581   kludge64 pos;
 582   va_list ap;
 583   int rc = 0;
 584
 585   va_start(ap, op);
 586
 587   switch (op) {
 588     case GRAND_CHECK:
 589       switch (va_arg(ap, unsigned)) {
 590         case GRAND_CHECK:
 591         case GRAND_SEEDINT:
 592         case GRAND_SEEDUINT32:
 593         case GRAND_SEEDBLOCK:
 594         case GRAND_SEEDRAND:
 595         case CHACHA_SEEK:
 596         case CHACHA_SEEKU64:
 597         case CHACHA_TELL:
 598         case CHACHA_TELLU64:
 599           rc = 1;
 600           break;
 601         default:
 602           rc = 0;
 603           break;
 604       }
 605       break;
 606
 607     case GRAND_SEEDINT:
 608       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 609       memset(buf + 4, 0, g->ops->noncesz - 4);
 610       g->ops->setnonce(g, buf);
 611       break;
 612     case GRAND_SEEDUINT32:
 613       i = va_arg(ap, uint32); STORE32_L(buf, i);
 614       memset(buf + 4, 0, g->ops->noncesz - 4);
 615       g->ops->setnonce(g, buf);
 616       break;
 617     case GRAND_SEEDBLOCK:
 618       p = va_arg(ap, const void *);
 619       sz = va_arg(ap, size_t);
 620       if (sz < g->ops->noncesz) {
 621         memcpy(buf, p, sz);
 622         memset(buf + sz, 0, g->ops->noncesz - sz);
 623         p = buf;
 624       }
 625       g->ops->setnonce(g, p);
 626       break;
 627     case GRAND_SEEDRAND:
 628       rr = va_arg(ap, grand *);
 629       rr->ops->fill(rr, buf, g->ops->noncesz);
 630       g->ops->setnonce(g, buf);
 631       break;
 632     case CHACHA_SEEK:
 633       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 634       g->ops->seek(g, pos);
 635       break;
 636     case CHACHA_SEEKU64:
 637       pos = va_arg(ap, kludge64);
 638       g->ops->seek(g, pos);
 639       break;
 640     case CHACHA_TELL:
 641       pos = g->ops->tell(g);
 642       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 643       break;
 644     case CHACHA_TELLU64:
 645       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 646       break;
 647     default:
 648       GRAND_BADOP;
 649       break;
 650   }
 651
 652   return (rc);
 653 }
 654
 655 static octet grbyte(grand *r)
 656 {
 657   grbasectx *g = (grbasectx *)r;
 658   octet o;
 659   g->ops->generate(g, &o, 1);
 660   return (o);
 661 }
 662
 663 static uint32 grword(grand *r)
 664 {
 665   grbasectx *g = (grbasectx *)r;
 666   octet b[4];
 667   g->ops->generate(g, b, sizeof(b));
 668   return (LOAD32_L(b));
 669 }
 670
 671 static void grfill(grand *r, void *p, size_t sz)
 672 {
 673   grbasectx *g = (grbasectx *)r;
 674   g->ops->generate(r, p, sz);
 675 }
 676
 677 typedef struct grctx {
 678   grbasectx r;
 679   chacha_ctx ctx;
 680 } grctx;
 681
 682 static void gr_seek(void *r, kludge64 pos)
 683   { grctx *g = r; chacha_seeku64(&g->ctx, pos); }
 684
 685 static kludge64 gr_tell(void *r)
 686   { grctx *g = r; return (chacha_tellu64(&g->ctx)); }
 687
 688 static void gr_setnonce(void *r, const void *n)
 689   { grctx *g = r; chacha_setnonce(&g->ctx, n); }
 690
 691 static void grdestroy(grand *r)
 692   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 693
 694 #define DEFGRAND(rr)                                                    \
 695                                                                         \
 696   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 697     { grctx *g = r; CHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }            \
 698                                                                         \
 699   static const grops grops_##rr =                                       \
 700     { CHACHA_NONCESZ, gr_seek, gr_tell,                                 \
 701       gr_setnonce, gr_generate_##rr };                                  \
 702                                                                         \
 703   static const grand_ops grops_rand_##rr = {                            \
 704     "chacha" #rr, GRAND_CRYPTO, 0,                                      \
 705     grmisc, grdestroy, grword,                                          \
 706     grbyte, grword, grand_defaultrange, grfill                          \
 707   };                                                                    \
 708                                                                         \
 709   grand *chacha##rr##_rand(const void *k, size_t ksz, const void *n)    \
 710   {                                                                     \
 711     grctx *g = S_CREATE(g);                                             \
 712     g->r.r.ops = &grops_rand_##rr;                                      \
 713     g->r.ops = &grops_##rr;                                             \
 714     chacha_init(&g->ctx, k, ksz, n);                                    \
 715     return (&g->r.r);                                                   \
 716   }
 717 CHACHA_VARS(DEFGRAND)
 718
 719 #define DEFXGRAND(rr)                                                   \
 720                                                                         \
 721   typedef struct grxctx_##rr {                                          \
 722     grbasectx r;                                                        \
 723     XCHACHA_CTX(rr) ctx;                                                \
 724   } grxctx_##rr;                                                        \
 725                                                                         \
 726   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 727     { grxctx_##rr *g = r; XCHACHA_SEEKU64(rr, &g->ctx, pos); }          \
 728                                                                         \
 729   static kludge64 grx_tell_##rr(void *r)                                \
 730     { grxctx_##rr *g = r; return (XCHACHA_TELLU64(rr, &g->ctx)); }      \
 731                                                                         \
 732   static void grx_setnonce_##rr(void *r, const void *n)                 \
 733     { grxctx_##rr *g = r; XCHACHA_SETNONCE(rr, &g->ctx, n); }           \
 734                                                                         \
 735   static void grxdestroy_##rr(grand *r)                                 \
 736     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 737                                                                         \
 738   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 739     { grxctx_##rr *g = r; XCHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }     \
 740                                                                         \
 741   static const grops grxops_##rr =                                      \
 742     { XCHACHA_NONCESZ, grx_seek_##rr, grx_tell_##rr,                    \
 743       grx_setnonce_##rr, grx_generate_##rr };                           \
 744                                                                         \
 745   static const grand_ops grxops_rand_##rr = {                           \
 746     "xchacha" #rr, GRAND_CRYPTO, 0,                                     \
 747     grmisc, grxdestroy_##rr, grword,                                    \
 748     grbyte, grword, grand_defaultrange, grfill                          \
 749   };                                                                    \
 750                                                                         \
 751   grand *xchacha##rr##_rand(const void *k, size_t ksz, const void *n)   \
 752   {                                                                     \
 753     grxctx_##rr *g = S_CREATE(g);                                       \
 754     g->r.r.ops = &grxops_rand_##rr;                                     \
 755     g->r.ops = &grxops_##rr;                                            \
 756     XCHACHA_INIT(rr, &g->ctx, k, ksz, n);                               \
 757     return (&g->r.r);                                                   \
 758   }
 759 CHACHA_VARS(DEFXGRAND)
 760
 761 /*----- Test rig ----------------------------------------------------------*/
 762
 763 #ifdef TEST_RIG
 764
 765 #include <stdio.h>
 766 #include <string.h>
 767
 768 #include <mLib/quis.h>
 769 #include <mLib/testrig.h>
 770
 771 #define DEFVCORE(r)                                                     \
 772   static int v_core_##r(dstr *v)                                        \
 773   {                                                                     \
 774     chacha_matrix a, b;                                                 \
 775     dstr d = DSTR_INIT;                                                 \
 776     int i, n;                                                           \
 777     int ok = 1;                                                         \
 778                                                                         \
 779     DENSURE(&d, CHACHA_OUTSZ); d.len = CHACHA_OUTSZ;                    \
 780     n = *(int *)v[0].buf;                                               \
 781     for (i = 0; i < CHACHA_OUTSZ/4; i++)                                \
 782       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 783     for (i = 0; i < n; i++) {                                           \
 784       core(r, a, b);                                                    \
 785       memcpy(a, b, sizeof(a));                                          \
 786     }                                                                   \
 787     for (i = 0; i < CHACHA_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]);  \
 788                                                                         \
 789     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 790       ok = 0;                                                           \
 791       printf("\nfail core:"                                             \
 792              "\n\titerations = %d"                                      \
 793              "\n\tin       = ", n);                                     \
 794       type_hex.dump(&v[1], stdout);                                     \
 795       printf("\n\texpected   = ");                                      \
 796       type_hex.dump(&v[2], stdout);                                     \
 797       printf("\n\tcalculated = ");                                      \
 798       type_hex.dump(&d, stdout);                                        \
 799       putchar('\n');                                                    \
 800     }                                                                   \
 801                                                                         \
 802     dstr_destroy(&d);                                                   \
 803     return (ok);                                                        \
 804   }
 805 CHACHA_VARS(DEFVCORE)
 806
 807 #define CHACHA_CTX(r) chacha_ctx
 808 #define CHACHA_INIT(r, ctx, k, ksz, n) chacha_init(ctx, k, ksz, n)
 809 #define CHACHA_SEEKU64(r, ctx, i) chacha_seeku64(ctx, i)
 810 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 811
 812 #define DEFxVENC(base, BASE, r)                                         \
 813   static int v_encrypt_##base##_##r(dstr *v)                            \
 814   {                                                                     \
 815     BASE##_CTX(r) ctx;                                                  \
 816     dstr d = DSTR_INIT;                                                 \
 817     kludge64 pos;                                                       \
 818     const octet *p, *p0;                                                \
 819     octet *q;                                                           \
 820     size_t sz, sz0, step;                                               \
 821     unsigned long skip;                                                 \
 822     int ok = 1;                                                         \
 823                                                                         \
 824     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 825     else { p0 = 0; sz0 = v[5].len; }                                    \
 826     DENSURE(&d, sz0); d.len = sz0;                                      \
 827     skip = *(unsigned long *)v[3].buf;                                  \
 828                                                                         \
 829     step = 0;                                                           \
 830     while (step < sz0 + skip) {                                         \
 831       step = step ? 3*step + 4 : 1;                                     \
 832       if (step > sz0 + skip) step = sz0 + skip;                         \
 833       BASE##_INIT(r, &ctx, v[0].buf, v[0].len, v[1].buf);               \
 834       if (v[2].len) {                                                   \
 835         LOAD64_(pos, v[2].buf);                                         \
 836         BASE##_SEEKU64(r, &ctx, pos);                                   \
 837       }                                                                 \
 838                                                                         \
 839       for (sz = skip; sz >= step; sz -= step)                           \
 840         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 841       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 842       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 843            sz >= step;                                                  \
 844            sz -= step, q += step) {                                     \
 845         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 846         if (p) p += step;                                               \
 847       }                                                                 \
 848       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 849                                                                         \
 850       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 851         ok = 0;                                                         \
 852         printf("\nfail encrypt:"                                        \
 853                "\n\tstep           = %lu"                               \
 854                "\n\tkey    = ", (unsigned long)step);                   \
 855         type_hex.dump(&v[0], stdout);                                   \
 856         printf("\n\tnonce          = ");                                \
 857         type_hex.dump(&v[1], stdout);                                   \
 858         printf("\n\tposition   = ");                                    \
 859         type_hex.dump(&v[2], stdout);                                   \
 860         printf("\n\tskip           = %lu", skip);                       \
 861         printf("\n\tmessage    = ");                                    \
 862         type_hex.dump(&v[4], stdout);                                   \
 863         printf("\n\texpected   = ");                                    \
 864         type_hex.dump(&v[5], stdout);                                   \
 865         printf("\n\tcalculated = ");                                    \
 866         type_hex.dump(&d, stdout);                                      \
 867         putchar('\n');                                                  \
 868       }                                                                 \
 869     }                                                                   \
 870                                                                         \
 871     dstr_destroy(&d);                                                   \
 872     return (ok);                                                        \
 873   }
 874 #define DEFVENC(r) DEFxVENC(chacha, CHACHA, r)
 875 #define DEFXVENC(r) DEFxVENC(xchacha, XCHACHA, r)
 876 CHACHA_VARS(DEFVENC)
 877 CHACHA_VARS(DEFXVENC)
 878
 879 static test_chunk defs[] = {
 880 #define DEFxTAB(base, r)                                                \
 881   { #base #r, v_encrypt_##base##_##r,                                   \
 882     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 883       &type_hex, &type_hex, 0 } },
 884 #define DEFTAB(r)                                                       \
 885   { "chacha" #r "-core", v_core_##r,                                    \
 886     { &type_int, &type_hex, &type_hex, 0 } },                           \
 887   DEFxTAB(chacha, r)
 888 #define DEFXTAB(r) DEFxTAB(xchacha, r)
 889 CHACHA_VARS(DEFTAB)
 890 CHACHA_VARS(DEFXTAB)
 891   { 0, 0, { 0 } }
 892 };
 893
 894 int main(int argc, char *argv[])
 895 {
 896   test_run(argc, argv, defs, SRCDIR"/t/chacha");
 897   return (0);
 898 }
 899
 900 #endif
 901
 902 /*----- That's all, folks -------------------------------------------------*/