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{,_ietf}@ --- *
 167  *
 168  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 169  *              @const void *nonce@ = the nonce (@CHACHA_NONCESZ@ or
 170  *                      @CHACHA_IETF_NONCESZ@ bytes)
 171  *
 172  * Returns:     ---
 173  *
 174  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 175  *              different message.  The stream position is reset to zero (see
 176  *              @chacha_seek@ etc.).
 177  */
 178
 179 void chacha_setnonce(chacha_ctx *ctx, const void *nonce)
 180 {
 181   const octet *n = nonce;
 182
 183   ctx->a[14] = LOAD32_L(n + 0);
 184   ctx->a[15] = LOAD32_L(n + 4);
 185   chacha_seek(ctx, 0);
 186 }
 187
 188 void chacha_setnonce_ietf(chacha_ctx *ctx, const void *nonce)
 189 {
 190   const octet *n = nonce;
 191
 192   ctx->a[13] = LOAD32_L(n + 0);
 193   ctx->a[14] = LOAD32_L(n + 4);
 194   ctx->a[15] = LOAD32_L(n + 8);
 195   chacha_seek_ietf(ctx, 0);
 196 }
 197
 198 /* --- @chacha_seek{,u64,_ietf}@ --- *
 199  *
 200  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 201  *              @unsigned long i@, @kludge64 i@, @uint32 i@ = new position
 202  *
 203  * Returns:     ---
 204  *
 205  * Use:         Sets a new stream position, in units of Chacha output
 206  *              blocks, which are @CHACHA_OUTSZ@ bytes each.  Byte
 207  *              granularity can be achieved by calling @chachaR_encrypt@
 208  *              appropriately.
 209  */
 210
 211 void chacha_seek(chacha_ctx *ctx, unsigned long i)
 212   { kludge64 ii; ASSIGN64(ii, i); chacha_seeku64(ctx, ii); }
 213
 214 void chacha_seeku64(chacha_ctx *ctx, kludge64 i)
 215 {
 216   ctx->a[12] = LO64(i); ctx->a[13] = HI64(i);
 217   ctx->bufi = CHACHA_OUTSZ;
 218 }
 219
 220 void chacha_seek_ietf(chacha_ctx *ctx, uint32 i)
 221   { ctx->a[12] = i; }
 222
 223 /* --- @chacha_tell{,u64,_ietf}@ --- *
 224  *
 225  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 226  *
 227  * Returns:     The current position in the output stream, in blocks,
 228  *              rounding upwards.
 229  */
 230
 231 unsigned long chacha_tell(chacha_ctx *ctx)
 232   { kludge64 i = chacha_tellu64(ctx); return (GET64(unsigned long, i)); }
 233
 234 kludge64 chacha_tellu64(chacha_ctx *ctx)
 235   { kludge64 i; SET64(i, ctx->a[13], ctx->a[12]); return (i); }
 236
 237 uint32 chacha_tell_ietf(chacha_ctx *ctx)
 238   { return (ctx->a[12]); }
 239
 240 /* --- @chacha{20,12,8}_encrypt@ --- *
 241  *
 242  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 243  *              @const void *src@ = source buffer (or null)
 244  *              @void *dest@ = destination buffer (or null)
 245  *              @size_t sz@ = size of the buffers
 246  *
 247  * Returns:     ---
 248  *
 249  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 250  *              ChaCha works by XORing plaintext with a keystream, so
 251  *              encryption and decryption are the same operation.  If @dest@
 252  *              is null then ignore @src@ and skip @sz@ bytes of the
 253  *              keystream.  If @src@ is null, then just write the keystream
 254  *              to @dest@.
 255  */
 256
 257 #define CHACHA_ENCRYPT(r, ctx, src, dest, sz)                           \
 258   chacha##r##_encrypt(ctx, src, dest, sz)
 259 #define DEFENCRYPT(r)                                                   \
 260   void CHACHA_ENCRYPT(r, chacha_ctx *ctx, const void *src,              \
 261                       void *dest, size_t sz)                            \
 262   {                                                                     \
 263     chacha_matrix b;                                                    \
 264     const octet *s = src;                                               \
 265     octet *d = dest;                                                    \
 266     size_t n;                                                           \
 267     kludge64 pos, delta;                                                \
 268                                                                         \
 269     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 270     if (!sz) return;                                                    \
 271                                                                         \
 272     if (!dest) {                                                        \
 273       n = sz/CHACHA_OUTSZ;                                              \
 274       pos = chacha_tellu64(ctx);                                        \
 275       ASSIGN64(delta, n);                                               \
 276       ADD64(pos, pos, delta);                                           \
 277       chacha_seeku64(ctx, pos);                                         \
 278       sz = sz%CHACHA_OUTSZ;                                             \
 279     } else if (!src) {                                                  \
 280       while (sz >= CHACHA_OUTSZ) {                                      \
 281         core(r, ctx->a, b);                                             \
 282         CHACHA_STEP(ctx->a);                                            \
 283         SALSA20_GENFULL(b, d);                                          \
 284         sz -= CHACHA_OUTSZ;                                             \
 285       }                                                                 \
 286     } else {                                                            \
 287       while (sz >= CHACHA_OUTSZ) {                                      \
 288         core(r, ctx->a, b);                                             \
 289         CHACHA_STEP(ctx->a);                                            \
 290         SALSA20_MIXFULL(b, d, s);                                       \
 291         sz -= CHACHA_OUTSZ;                                             \
 292       }                                                                 \
 293     }                                                                   \
 294                                                                         \
 295     if (sz) {                                                           \
 296       core(r, ctx->a, b);                                               \
 297       CHACHA_STEP(ctx->a);                                              \
 298       SALSA20_PREPBUF(ctx, b);                                          \
 299       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 300       assert(!sz);                                                      \
 301     }                                                                   \
 302   }
 303 CHACHA_VARS(DEFENCRYPT)
 304
 305 /*----- HChaCha implementation --------------------------------------------*/
 306
 307 #define HCHACHA_RAW(r, ctx, src, dest) hchacha##r##_raw(ctx, src, dest)
 308 #define HCHACHA_PRF(r, ctx, src, dest) hchacha##r##_prf(ctx, src, dest)
 309
 310 /* --- @hchacha{20,12,8}_prf@ --- *
 311  *
 312  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 313  *              @const void *src@ = the input (@HCHACHA_INSZ@ bytes)
 314  *              @void *dest@ = the output (@HCHACHA_OUTSZ@ bytes)
 315  *
 316  * Returns:     ---
 317  *
 318  * Use:         Apply the HChacha/r pseudorandom function to @src@, writing
 319  *              the result to @out@.
 320  */
 321
 322 #define DEFHCHACHA(r)                                                   \
 323   static void HCHACHA_RAW(r, chacha_matrix k,                           \
 324                           const uint32 *src, uint32 *dest)              \
 325   {                                                                     \
 326     chacha_matrix a;                                                    \
 327     int i;                                                              \
 328                                                                         \
 329     /* --- HChaCha, computed from full ChaCha --- *                     \
 330      *                                                                  \
 331      * The security proof makes use of the fact that HChaCha (i.e.,     \
 332      * without the final feedforward step) can be computed from full    \
 333      * ChaCha using only knowledge of the non-secret input.  I don't    \
 334      * want to compromise the performance of the main function by       \
 335      * making the feedforward step separate, but this operation is less \
 336      * speed critical, so we do it the harder way.                      \
 337      */                                                                 \
 338                                                                         \
 339     for (i = 0; i < 4; i++) k[12 + i] = src[i];                         \
 340     core(r, k, a);                                                      \
 341     for (i = 0; i < 8; i++) dest[i] = a[(i + 4)^4] - k[(i + 4)^4];      \
 342   }                                                                     \
 343                                                                         \
 344   void HCHACHA_PRF(r, chacha_ctx *ctx, const void *src, void *dest)     \
 345   {                                                                     \
 346     const octet *s = src;                                               \
 347     octet *d = dest;                                                    \
 348     uint32 in[4], out[8];                                               \
 349     int i;                                                              \
 350                                                                         \
 351     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 352     HCHACHA_RAW(r, ctx->a, in, out);                                    \
 353     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 354   }
 355 CHACHA_VARS(DEFHCHACHA)
 356
 357 /*----- XChaCha implementation -------------------------------------------*/
 358
 359 /* --- Some convenient macros for naming functions --- *
 360  *
 361  * Because the crypto core is involved in XChaCha/r's per-nonce setup, we
 362  * need to take an interest in the number of rounds in most of the various
 363  * functions, and it will probably help if we distinguish the context
 364  * structures for the various versions.
 365  */
 366
 367 #define XCHACHA_CTX(r) xchacha##r##_ctx
 368 #define XCHACHA_INIT(r, ctx, k, ksz, n) xchacha##r##_init(ctx, k, ksz, n)
 369 #define XCHACHA_SETNONCE(r, ctx, n) xchacha##r##_setnonce(ctx, n)
 370 #define XCHACHA_SEEK(r, ctx, i) xchacha##r##_seek(ctx, i)
 371 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 372 #define XCHACHA_TELL(r, ctx) xchacha##r##_tell(ctx)
 373 #define XCHACHA_TELLU64(r, ctx) xchacha##r##_tellu64(ctx)
 374 #define XCHACHA_ENCRYPT(r, ctx, src, dest, sz)                          \
 375   xchacha##r##_encrypt(ctx, src, dest, sz)
 376
 377 /* --- @xchacha{20,12,8}_init@ --- *
 378  *
 379  * Arguments:   @xchachaR_ctx *ctx@ = the context to fill in
 380  *              @const void *key@ = pointer to key material
 381  *              @size_t ksz@ = size of key (either 32 or 16)
 382  *              @const void *nonce@ = initial nonce, or null
 383  *
 384  * Returns:     ---
 385  *
 386  * Use:         Initializes an XChaCha/r context ready for use.
 387  *
 388  *              There is a different function for each number of rounds,
 389  *              unlike for plain ChaCha.
 390  */
 391
 392 #define DEFXINIT(r)                                                     \
 393   void XCHACHA_INIT(r, XCHACHA_CTX(r) *ctx,                             \
 394                     const void *key, size_t ksz, const void *nonce)     \
 395   {                                                                     \
 396     static const octet zerononce[XCHACHA_NONCESZ];                      \
 397                                                                         \
 398     populate(ctx->k, key, ksz);                                         \
 399     ctx->s.a[ 0] = CHACHA_A256;                                         \
 400     ctx->s.a[ 1] = CHACHA_B256;                                         \
 401     ctx->s.a[ 2] = CHACHA_C256;                                         \
 402     ctx->s.a[ 3] = CHACHA_D256;                                         \
 403     XCHACHA_SETNONCE(r, ctx, nonce ? nonce : zerononce);                \
 404   }
 405 CHACHA_VARS(DEFXINIT)
 406
 407 /* --- @xchacha{20,12,8}_setnonce@ --- *
 408  *
 409  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 410  *              @const void *nonce@ = the nonce (@XCHACHA_NONCESZ@ bytes)
 411  *
 412  * Returns:     ---
 413  *
 414  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 415  *              different message.  The stream position is reset to zero (see
 416  *              @chacha_seek@ etc.).
 417  *
 418  *              There is a different function for each number of rounds,
 419  *              unlike for plain ChaCha.
 420  */
 421
 422 #define DEFXNONCE(r)                                                    \
 423   void XCHACHA_SETNONCE(r, XCHACHA_CTX(r) *ctx, const void *nonce)      \
 424   {                                                                     \
 425     const octet *n = nonce;                                             \
 426     uint32 in[4];                                                       \
 427     int i;                                                              \
 428                                                                         \
 429     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 430     HCHACHA_RAW(r, ctx->k, in, ctx->s.a + 4);                           \
 431     chacha_setnonce(&ctx->s, n + 16);                                   \
 432   }
 433 CHACHA_VARS(DEFXNONCE)
 434
 435 /* --- @xchacha{20,12,8}_seek{,u64}@ --- *
 436  *
 437  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 438  *              @unsigned long i@, @kludge64 i@ = new position to set
 439  *
 440  * Returns:     ---
 441  *
 442  * Use:         Sets a new stream position, in units of ChaCha output
 443  *              blocks, which are @XCHACHA_OUTSZ@ bytes each.  Byte
 444  *              granularity can be achieved by calling @xchachaR_encrypt@
 445  *              appropriately.
 446  *
 447  *              There is a different function for each number of rounds,
 448  *              unlike for plain ChaCha, because the context structures are
 449  *              different.
 450  */
 451
 452 /* --- @xchacha{20,12,8}_tell{,u64}@ --- *
 453  *
 454  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 455  *
 456  * Returns:     The current position in the output stream, in blocks,
 457  *              rounding upwards.
 458  *
 459  *              There is a different function for each number of rounds,
 460  *              unlike for plain ChaCha, because the context structures are
 461  *              different.
 462  */
 463
 464 /* --- @xchacha{20,12,8}_encrypt@ --- *
 465  *
 466  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 467  *              @const void *src@ = source buffer (or null)
 468  *              @void *dest@ = destination buffer (or null)
 469  *              @size_t sz@ = size of the buffers
 470  *
 471  * Returns:     ---
 472  *
 473  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 474  *              XChaCha works by XORing plaintext with a keystream, so
 475  *              encryption and decryption are the same operation.  If @dest@
 476  *              is null then ignore @src@ and skip @sz@ bytes of the
 477  *              keystream.  If @src@ is null, then just write the keystream
 478  *              to @dest@.
 479  */
 480
 481 #define DEFXPASSTHRU(r)                                                 \
 482   void XCHACHA_SEEK(r, XCHACHA_CTX(r) *ctx, unsigned long i)            \
 483     { chacha_seek(&ctx->s, i); }                                        \
 484   void XCHACHA_SEEKU64(r, XCHACHA_CTX(r) *ctx, kludge64 i)              \
 485     { chacha_seeku64(&ctx->s, i); }                                     \
 486   unsigned long XCHACHA_TELL(r, XCHACHA_CTX(r) *ctx)                    \
 487     { return chacha_tell(&ctx->s); }                                    \
 488   kludge64 XCHACHA_TELLU64(r, XCHACHA_CTX(r) *ctx)                      \
 489     { return chacha_tellu64(&ctx->s); }                                 \
 490   void XCHACHA_ENCRYPT(r, XCHACHA_CTX(r) *ctx,                          \
 491                         const void *src, void *dest, size_t sz)         \
 492     { CHACHA_ENCRYPT(r, &ctx->s, src, dest, sz); }
 493 CHACHA_VARS(DEFXPASSTHRU)
 494
 495 /*----- Generic cipher interface ------------------------------------------*/
 496
 497 typedef struct gctx { gcipher c; chacha_ctx ctx; } gctx;
 498
 499 static void gsetiv(gcipher *c, const void *iv)
 500   { gctx *g = (gctx *)c; chacha_setnonce(&g->ctx, iv); }
 501
 502 static void gsetiv_ietf(gcipher *c, const void *iv)
 503   { gctx *g = (gctx *)c; chacha_setnonce_ietf(&g->ctx, iv); }
 504
 505 static void gdestroy(gcipher *c)
 506   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 507
 508 static gcipher *ginit(const void *k, size_t sz, const gcipher_ops *ops)
 509 {
 510   gctx *g = S_CREATE(gctx);
 511   g->c.ops = ops;
 512   chacha_init(&g->ctx, k, sz, 0);
 513   return (&g->c);
 514 }
 515
 516 #define DEFGCIPHER(r)                                                   \
 517                                                                         \
 518   static const gcipher_ops gops_##r, gops_##r##_ietf;                   \
 519                                                                         \
 520   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 521     { return (ginit(k, sz, &gops_##r)); }                               \
 522                                                                         \
 523   static gcipher *ginit_##r##_ietf(const void *k, size_t sz)            \
 524     { return (ginit(k, sz, &gops_##r##_ietf)); }                        \
 525                                                                         \
 526   static void gencrypt_##r(gcipher *c, const void *s,                   \
 527                            void *t, size_t sz)                          \
 528     { gctx *g = (gctx *)c; CHACHA_ENCRYPT(r, &g->ctx, s, t, sz); }      \
 529                                                                         \
 530   static const gcipher_ops gops_##r = {                                 \
 531     &chacha##r,                                                         \
 532     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 533   };                                                                    \
 534                                                                         \
 535   static const gcipher_ops gops_##r##_ietf = {                          \
 536     &chacha##r##_ietf,                                                  \
 537     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv_ietf, 0                \
 538   };                                                                    \
 539                                                                         \
 540   const gccipher chacha##r = {                                          \
 541     "chacha" #r, chacha_keysz,                                          \
 542     CHACHA_NONCESZ, ginit_##r                                           \
 543   };                                                                    \
 544                                                                         \
 545   const gccipher chacha##r##_ietf = {                                   \
 546     "chacha" #r "-ietf", chacha_keysz,                                  \
 547     CHACHA_IETF_NONCESZ, ginit_##r##_ietf                               \
 548   };
 549
 550 CHACHA_VARS(DEFGCIPHER)
 551
 552 #define DEFGXCIPHER(r)                                                  \
 553                                                                         \
 554   typedef struct { gcipher c; XCHACHA_CTX(r) ctx; } gxctx_##r;          \
 555                                                                         \
 556   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 557     { gxctx_##r *g = (gxctx_##r *)c; XCHACHA_SETNONCE(r, &g->ctx, iv); } \
 558                                                                         \
 559   static void gxdestroy_##r(gcipher *c)                                 \
 560     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 561                                                                         \
 562   static const gcipher_ops gxops_##r;                                   \
 563                                                                         \
 564   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 565   {                                                                     \
 566     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 567     g->c.ops = &gxops_##r;                                              \
 568     XCHACHA_INIT(r, &g->ctx, k, sz, 0);                                 \
 569     return (&g->c);                                                     \
 570   }                                                                     \
 571                                                                         \
 572   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 573                             void *t, size_t sz)                         \
 574   {                                                                     \
 575     gxctx_##r *g = (gxctx_##r *)c;                                      \
 576     XCHACHA_ENCRYPT(r, &g->ctx, s, t, sz);                              \
 577   }                                                                     \
 578                                                                         \
 579   static const gcipher_ops gxops_##r = {                                \
 580     &xchacha##r,                                                        \
 581     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 582   };                                                                    \
 583                                                                         \
 584   const gccipher xchacha##r = {                                         \
 585     "xchacha" #r, chacha_keysz,                                         \
 586     CHACHA_NONCESZ, gxinit_##r                                          \
 587   };
 588
 589 CHACHA_VARS(DEFGXCIPHER)
 590
 591 /*----- Generic random number generator interface -------------------------*/
 592
 593 typedef struct grops {
 594   size_t noncesz;
 595   void (*seek)(void *, kludge64);
 596   kludge64 (*tell)(void *);
 597   void (*setnonce)(void *, const void *);
 598   void (*generate)(void *, void *, size_t);
 599 } grops;
 600
 601 typedef struct grbasectx {
 602   grand r;
 603   const grops *ops;
 604 } grbasectx;
 605
 606 static int grmisc(grand *r, unsigned op, ...)
 607 {
 608   octet buf[XCHACHA_NONCESZ];
 609   grbasectx *g = (grbasectx *)r;
 610   grand *rr;
 611   const octet *p;
 612   size_t sz;
 613   uint32 i;
 614   unsigned long ul;
 615   kludge64 pos;
 616   va_list ap;
 617   int rc = 0;
 618
 619   va_start(ap, op);
 620
 621   switch (op) {
 622     case GRAND_CHECK:
 623       switch (va_arg(ap, unsigned)) {
 624         case GRAND_CHECK:
 625         case GRAND_SEEDINT:
 626         case GRAND_SEEDUINT32:
 627         case GRAND_SEEDBLOCK:
 628         case GRAND_SEEDRAND:
 629         case CHACHA_SEEK:
 630         case CHACHA_SEEKU64:
 631         case CHACHA_TELL:
 632         case CHACHA_TELLU64:
 633           rc = 1;
 634           break;
 635         default:
 636           rc = 0;
 637           break;
 638       }
 639       break;
 640
 641     case GRAND_SEEDINT:
 642       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 643       memset(buf + 4, 0, g->ops->noncesz - 4);
 644       g->ops->setnonce(g, buf);
 645       break;
 646     case GRAND_SEEDUINT32:
 647       i = va_arg(ap, uint32); STORE32_L(buf, i);
 648       memset(buf + 4, 0, g->ops->noncesz - 4);
 649       g->ops->setnonce(g, buf);
 650       break;
 651     case GRAND_SEEDBLOCK:
 652       p = va_arg(ap, const void *);
 653       sz = va_arg(ap, size_t);
 654       if (sz < g->ops->noncesz) {
 655         memcpy(buf, p, sz);
 656         memset(buf + sz, 0, g->ops->noncesz - sz);
 657         p = buf;
 658       }
 659       g->ops->setnonce(g, p);
 660       break;
 661     case GRAND_SEEDRAND:
 662       rr = va_arg(ap, grand *);
 663       rr->ops->fill(rr, buf, g->ops->noncesz);
 664       g->ops->setnonce(g, buf);
 665       break;
 666     case CHACHA_SEEK:
 667       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 668       g->ops->seek(g, pos);
 669       break;
 670     case CHACHA_SEEKU64:
 671       pos = va_arg(ap, kludge64);
 672       g->ops->seek(g, pos);
 673       break;
 674     case CHACHA_TELL:
 675       pos = g->ops->tell(g);
 676       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 677       break;
 678     case CHACHA_TELLU64:
 679       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 680       break;
 681     default:
 682       GRAND_BADOP;
 683       break;
 684   }
 685
 686   return (rc);
 687 }
 688
 689 static octet grbyte(grand *r)
 690 {
 691   grbasectx *g = (grbasectx *)r;
 692   octet o;
 693   g->ops->generate(g, &o, 1);
 694   return (o);
 695 }
 696
 697 static uint32 grword(grand *r)
 698 {
 699   grbasectx *g = (grbasectx *)r;
 700   octet b[4];
 701   g->ops->generate(g, b, sizeof(b));
 702   return (LOAD32_L(b));
 703 }
 704
 705 static void grfill(grand *r, void *p, size_t sz)
 706 {
 707   grbasectx *g = (grbasectx *)r;
 708   g->ops->generate(r, p, sz);
 709 }
 710
 711 typedef struct grctx {
 712   grbasectx r;
 713   chacha_ctx ctx;
 714 } grctx;
 715
 716 static void gr_seek(void *r, kludge64 pos)
 717   { grctx *g = r; chacha_seeku64(&g->ctx, pos); }
 718
 719 static void gr_seek_ietf(void *r, kludge64 pos)
 720   { grctx *g = r; chacha_seek_ietf(&g->ctx, LO64(pos)); }
 721
 722 static kludge64 gr_tell(void *r)
 723   { grctx *g = r; return (chacha_tellu64(&g->ctx)); }
 724
 725 static kludge64 gr_tell_ietf(void *r)
 726 {
 727   grctx *g = r;
 728   kludge64 pos;
 729
 730   SET64(pos, 0, chacha_tell_ietf(&g->ctx));
 731   return (pos);
 732 }
 733
 734 static void gr_setnonce(void *r, const void *n)
 735   { grctx *g = r; chacha_setnonce(&g->ctx, n); }
 736
 737 static void gr_setnonce_ietf(void *r, const void *n)
 738   { grctx *g = r; chacha_setnonce_ietf(&g->ctx, n); }
 739
 740 static void grdestroy(grand *r)
 741   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 742
 743 static grand *grinit(const void *k, size_t ksz, const void *n,
 744                      const grand_ops *ops, const grops *myops)
 745 {
 746     grctx *g = S_CREATE(grctx);
 747     g->r.r.ops = ops;
 748     g->r.ops = myops;
 749     chacha_init(&g->ctx, k, ksz, 0);
 750     if (n) myops->setnonce(g, n);
 751     return (&g->r.r);
 752 }
 753
 754 #define DEFGRAND(rr)                                                    \
 755                                                                         \
 756   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 757     { grctx *g = r; CHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }            \
 758                                                                         \
 759   static const grops grops_##rr =                                       \
 760     { CHACHA_NONCESZ, gr_seek, gr_tell,                                 \
 761       gr_setnonce, gr_generate_##rr };                                  \
 762                                                                         \
 763   static const grops grops_##rr##_ietf =                                \
 764     { CHACHA_IETF_NONCESZ, gr_seek_ietf, gr_tell_ietf,                  \
 765       gr_setnonce_ietf, gr_generate_##rr };                             \
 766                                                                         \
 767   static const grand_ops grops_rand_##rr = {                            \
 768     "chacha" #rr, GRAND_CRYPTO, 0,                                      \
 769     grmisc, grdestroy, grword,                                          \
 770     grbyte, grword, grand_defaultrange, grfill                          \
 771   };                                                                    \
 772                                                                         \
 773   static const grand_ops grops_rand_##rr##_ietf = {                     \
 774     "chacha" #rr "-ietf", GRAND_CRYPTO, 0,                              \
 775     grmisc, grdestroy, grword,                                          \
 776     grbyte, grword, grand_defaultrange, grfill                          \
 777   };                                                                    \
 778                                                                         \
 779   grand *chacha##rr##_rand(const void *k, size_t ksz, const void *n)    \
 780     { return (grinit(k, ksz, n, &grops_rand_##rr, &grops_##rr)); }      \
 781                                                                         \
 782   grand *chacha##rr##_ietf_rand(const void *k, size_t ksz,              \
 783                                 const void *n)                          \
 784   {                                                                     \
 785     return (grinit(k, ksz, n,                                           \
 786                    &grops_rand_##rr##_ietf,                             \
 787                    &grops_##rr##_ietf));                                \
 788   }
 789
 790 CHACHA_VARS(DEFGRAND)
 791
 792 #define DEFXGRAND(rr)                                                   \
 793                                                                         \
 794   typedef struct grxctx_##rr {                                          \
 795     grbasectx r;                                                        \
 796     XCHACHA_CTX(rr) ctx;                                                \
 797   } grxctx_##rr;                                                        \
 798                                                                         \
 799   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 800     { grxctx_##rr *g = r; XCHACHA_SEEKU64(rr, &g->ctx, pos); }          \
 801                                                                         \
 802   static kludge64 grx_tell_##rr(void *r)                                \
 803     { grxctx_##rr *g = r; return (XCHACHA_TELLU64(rr, &g->ctx)); }      \
 804                                                                         \
 805   static void grx_setnonce_##rr(void *r, const void *n)                 \
 806     { grxctx_##rr *g = r; XCHACHA_SETNONCE(rr, &g->ctx, n); }           \
 807                                                                         \
 808   static void grxdestroy_##rr(grand *r)                                 \
 809     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 810                                                                         \
 811   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 812     { grxctx_##rr *g = r; XCHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }     \
 813                                                                         \
 814   static const grops grxops_##rr =                                      \
 815     { XCHACHA_NONCESZ, grx_seek_##rr, grx_tell_##rr,                    \
 816       grx_setnonce_##rr, grx_generate_##rr };                           \
 817                                                                         \
 818   static const grand_ops grxops_rand_##rr = {                           \
 819     "xchacha" #rr, GRAND_CRYPTO, 0,                                     \
 820     grmisc, grxdestroy_##rr, grword,                                    \
 821     grbyte, grword, grand_defaultrange, grfill                          \
 822   };                                                                    \
 823                                                                         \
 824   grand *xchacha##rr##_rand(const void *k, size_t ksz, const void *n)   \
 825   {                                                                     \
 826     grxctx_##rr *g = S_CREATE(grxctx_##rr);                             \
 827     g->r.r.ops = &grxops_rand_##rr;                                     \
 828     g->r.ops = &grxops_##rr;                                            \
 829     XCHACHA_INIT(rr, &g->ctx, k, ksz, n);                               \
 830     return (&g->r.r);                                                   \
 831   }
 832 CHACHA_VARS(DEFXGRAND)
 833
 834 /*----- Test rig ----------------------------------------------------------*/
 835
 836 #ifdef TEST_RIG
 837
 838 #include <stdio.h>
 839 #include <string.h>
 840
 841 #include <mLib/quis.h>
 842 #include <mLib/testrig.h>
 843
 844 #define DEFVCORE(r)                                                     \
 845   static int v_core_##r(dstr *v)                                        \
 846   {                                                                     \
 847     chacha_matrix a, b;                                                 \
 848     dstr d = DSTR_INIT;                                                 \
 849     int i, n;                                                           \
 850     int ok = 1;                                                         \
 851                                                                         \
 852     DENSURE(&d, CHACHA_OUTSZ); d.len = CHACHA_OUTSZ;                    \
 853     n = *(int *)v[0].buf;                                               \
 854     for (i = 0; i < CHACHA_OUTSZ/4; i++)                                \
 855       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 856     for (i = 0; i < n; i++) {                                           \
 857       core(r, a, b);                                                    \
 858       memcpy(a, b, sizeof(a));                                          \
 859     }                                                                   \
 860     for (i = 0; i < CHACHA_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]);  \
 861                                                                         \
 862     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 863       ok = 0;                                                           \
 864       printf("\nfail core:"                                             \
 865              "\n\titerations = %d"                                      \
 866              "\n\tin       = ", n);                                     \
 867       type_hex.dump(&v[1], stdout);                                     \
 868       printf("\n\texpected   = ");                                      \
 869       type_hex.dump(&v[2], stdout);                                     \
 870       printf("\n\tcalculated = ");                                      \
 871       type_hex.dump(&d, stdout);                                        \
 872       putchar('\n');                                                    \
 873     }                                                                   \
 874                                                                         \
 875     dstr_destroy(&d);                                                   \
 876     return (ok);                                                        \
 877   }
 878 CHACHA_VARS(DEFVCORE)
 879
 880 #define CHACHA_CTX(r) chacha_ctx
 881
 882 #define CHACHA_TESTSETUP(r, ctx, k, ksz, n, nsz, p, psz) do {           \
 883   kludge64 pos64;                                                       \
 884   chacha_init(ctx, k, ksz, 0);                                          \
 885   if (nsz == 8) chacha_setnonce(ctx, n);                                \
 886   else if (nsz == 12) chacha_setnonce_ietf(ctx, n);                     \
 887   if (psz == 8) { LOAD64_(pos64, p); chacha_seeku64(ctx, pos64); }      \
 888   else if (psz == 4) chacha_seek_ietf(ctx, LOAD32(p));                  \
 889 } while (0)
 890
 891 #define XCHACHA_TESTSETUP(r, ctx, k, ksz, n, nsz, p, psz) do {          \
 892   kludge64 pos64;                                                       \
 893   XCHACHA_INIT(r, ctx, k, ksz, 0);                                      \
 894   if (nsz == 24) XCHACHA_SETNONCE(r, ctx, n);                           \
 895   if (psz == 8) { LOAD64_(pos64, p); xchacha##r##_seeku64(ctx, pos64); } \
 896 } while (0)
 897
 898 #define DEFxVENC(base, BASE, r)                                         \
 899   static int v_encrypt_##base##_##r(dstr *v)                            \
 900   {                                                                     \
 901     BASE##_CTX(r) ctx;                                                  \
 902     dstr d = DSTR_INIT;                                                 \
 903     const octet *p, *p0;                                                \
 904     octet *q;                                                           \
 905     size_t sz, sz0, step;                                               \
 906     unsigned long skip;                                                 \
 907     int ok = 1;                                                         \
 908                                                                         \
 909     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 910     else { p0 = 0; sz0 = v[5].len; }                                    \
 911     DENSURE(&d, sz0); d.len = sz0;                                      \
 912     skip = *(unsigned long *)v[3].buf;                                  \
 913                                                                         \
 914     step = 0;                                                           \
 915     while (step < sz0 + skip) {                                         \
 916       step = step ? 3*step + 4 : 1;                                     \
 917       if (step > sz0 + skip) step = sz0 + skip;                         \
 918       BASE##_TESTSETUP(r, &ctx, v[0].buf, v[0].len,                     \
 919                        v[1].buf, v[1].len, v[2].buf, v[2].len);         \
 920                                                                         \
 921       for (sz = skip; sz >= step; sz -= step)                           \
 922         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 923       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 924       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 925            sz >= step;                                                  \
 926            sz -= step, q += step) {                                     \
 927         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 928         if (p) p += step;                                               \
 929       }                                                                 \
 930       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 931                                                                         \
 932       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 933         ok = 0;                                                         \
 934         printf("\nfail encrypt:"                                        \
 935                "\n\tstep           = %lu"                               \
 936                "\n\tkey    = ", (unsigned long)step);                   \
 937         type_hex.dump(&v[0], stdout);                                   \
 938         printf("\n\tnonce          = ");                                \
 939         type_hex.dump(&v[1], stdout);                                   \
 940         printf("\n\tposition   = ");                                    \
 941         type_hex.dump(&v[2], stdout);                                   \
 942         printf("\n\tskip           = %lu", skip);                       \
 943         printf("\n\tmessage    = ");                                    \
 944         type_hex.dump(&v[4], stdout);                                   \
 945         printf("\n\texpected   = ");                                    \
 946         type_hex.dump(&v[5], stdout);                                   \
 947         printf("\n\tcalculated = ");                                    \
 948         type_hex.dump(&d, stdout);                                      \
 949         putchar('\n');                                                  \
 950       }                                                                 \
 951     }                                                                   \
 952                                                                         \
 953     dstr_destroy(&d);                                                   \
 954     return (ok);                                                        \
 955   }
 956 #define DEFVENC(r) DEFxVENC(chacha, CHACHA, r)
 957 #define DEFXVENC(r) DEFxVENC(xchacha, XCHACHA, r)
 958 CHACHA_VARS(DEFVENC)
 959 CHACHA_VARS(DEFXVENC)
 960
 961 static test_chunk defs[] = {
 962 #define DEFxTAB(base, r)                                                \
 963   { #base #r, v_encrypt_##base##_##r,                                   \
 964     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 965       &type_hex, &type_hex, 0 } },
 966 #define DEFTAB(r)                                                       \
 967   { "chacha" #r "-core", v_core_##r,                                    \
 968     { &type_int, &type_hex, &type_hex, 0 } },                           \
 969   DEFxTAB(chacha, r)
 970 #define DEFXTAB(r) DEFxTAB(xchacha, r)
 971 CHACHA_VARS(DEFTAB)
 972 CHACHA_VARS(DEFXTAB)
 973   { 0, 0, { 0 } }
 974 };
 975
 976 int main(int argc, char *argv[])
 977 {
 978   test_run(argc, argv, defs, SRCDIR"/t/chacha");
 979   return (0);
 980 }
 981
 982 #endif
 983
 984 /*----- That's all, folks -------------------------------------------------*/