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