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 #ifdef CPUFAM_X86
  76 extern core__functype chacha_core_x86_sse2;
  77 #endif
  78
  79 static core__functype *pick_core(void)
  80 {
  81 #ifdef CPUFAM_X86
  82   if (cpu_feature_p(CPUFEAT_X86_SSE2)) return chacha_core_x86_sse2;
  83 #endif
  84   return simple_core;
  85 }
  86
  87 /* --- @populate@ --- *
  88  *
  89  * Arguments:   @chacha_matrix a@ = a matrix to fill in
  90  *              @const void *key@ = pointer to key material
  91  *              @size_t ksz@ = size of key
  92  *
  93  * Returns:     ---
  94  *
  95  * Use:         Fills in a ChaCha matrix from the key, setting the
  96  *              appropriate constants according to the key length.  The nonce
  97  *              and position words are left uninitialized.
  98  */
  99
 100 static void populate(chacha_matrix a, const void *key, size_t ksz)
 101 {
 102   const octet *k = key;
 103
 104   KSZ_ASSERT(chacha, ksz);
 105
 106   a[ 4] = LOAD32_L(k +  0);
 107   a[ 5] = LOAD32_L(k +  4);
 108   if (ksz == 10) {
 109     a[ 6] = LOAD16_L(k +  8);
 110     a[ 7] = 0;
 111   } else {
 112     a[ 6] = LOAD32_L(k +  8);
 113     a[ 7] = LOAD32_L(k + 12);
 114   }
 115   if (ksz <= 16) {
 116     a[ 8] = a[ 4];
 117     a[ 9] = a[ 5];
 118     a[10] = a[ 6];
 119     a[11] = a[ 7];
 120     a[ 0] = CHACHA_A128;
 121     a[ 1] = CHACHA_B128;
 122     a[ 2] = ksz == 10 ? CHACHA_C80 : CHACHA_C128;
 123     a[ 3] = CHACHA_D128;
 124   } else {
 125     a[ 8] = LOAD32_L(k + 16);
 126     a[ 9] = LOAD32_L(k + 20);
 127     a[10] = LOAD32_L(k + 24);
 128     a[11] = LOAD32_L(k + 28);
 129     a[ 0] = CHACHA_A256;
 130     a[ 1] = CHACHA_B256;
 131     a[ 2] = CHACHA_C256;
 132     a[ 3] = CHACHA_D256;
 133   }
 134 }
 135
 136 /*----- ChaCha implementation ---------------------------------------------*/
 137
 138 /* --- @chacha_init@ --- *
 139  *
 140  * Arguments:   @chacha_ctx *ctx@ = context to fill in
 141  *              @const void *key@ = pointer to key material
 142  *              @size_t ksz@ = size of key (either 32 or 16)
 143  *              @const void *nonce@ = initial nonce, or null
 144  *
 145  * Returns:     ---
 146  *
 147  * Use:         Initializes a ChaCha context ready for use.
 148  */
 149
 150 void chacha_init(chacha_ctx *ctx, const void *key, size_t ksz,
 151                   const void *nonce)
 152 {
 153   static const octet zerononce[CHACHA_NONCESZ];
 154
 155   populate(ctx->a, key, ksz);
 156   chacha_setnonce(ctx, nonce ? nonce : zerononce);
 157 }
 158
 159 /* --- @chacha_setnonce@ --- *
 160  *
 161  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 162  *              @const void *nonce@ = the nonce (@CHACHA_NONCESZ@ bytes)
 163  *
 164  * Returns:     ---
 165  *
 166  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 167  *              different message.  The stream position is reset to zero (see
 168  *              @chacha_seek@ etc.).
 169  */
 170
 171 void chacha_setnonce(chacha_ctx *ctx, const void *nonce)
 172 {
 173   const octet *n = nonce;
 174
 175   ctx->a[14] = LOAD32_L(n + 0);
 176   ctx->a[15] = LOAD32_L(n + 4);
 177   chacha_seek(ctx, 0);
 178 }
 179
 180 /* --- @chacha_seek@, @chacha_seeku64@ --- *
 181  *
 182  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 183  *              @unsigned long i@, @kludge64 i@ = new position to set
 184  *
 185  * Returns:     ---
 186  *
 187  * Use:         Sets a new stream position, in units of Chacha output
 188  *              blocks, which are @CHACHA_OUTSZ@ bytes each.  Byte
 189  *              granularity can be achieved by calling @chachaR_encrypt@
 190  *              appropriately.
 191  */
 192
 193 void chacha_seek(chacha_ctx *ctx, unsigned long i)
 194   { kludge64 ii; ASSIGN64(ii, i); chacha_seeku64(ctx, ii); }
 195
 196 void chacha_seeku64(chacha_ctx *ctx, kludge64 i)
 197 {
 198   ctx->a[12] = LO64(i); ctx->a[13] = HI64(i);
 199   ctx->bufi = CHACHA_OUTSZ;
 200 }
 201
 202 /* --- @chacha_tell@, @chacha_tellu64@ --- *
 203  *
 204  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 205  *
 206  * Returns:     The current position in the output stream, in blocks,
 207  *              rounding upwards.
 208  */
 209
 210 unsigned long chacha_tell(chacha_ctx *ctx)
 211   { kludge64 i = chacha_tellu64(ctx); return (GET64(unsigned long, i)); }
 212
 213 kludge64 chacha_tellu64(chacha_ctx *ctx)
 214   { kludge64 i; SET64(i, ctx->a[9], ctx->a[8]); return (i); }
 215
 216 /* --- @chacha{,12,8}_encrypt@ --- *
 217  *
 218  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 219  *              @const void *src@ = source buffer (or null)
 220  *              @void *dest@ = destination buffer (or null)
 221  *              @size_t sz@ = size of the buffers
 222  *
 223  * Returns:     ---
 224  *
 225  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 226  *              ChaCha works by XORing plaintext with a keystream, so
 227  *              encryption and decryption are the same operation.  If @dest@
 228  *              is null then ignore @src@ and skip @sz@ bytes of the
 229  *              keystream.  If @src@ is null, then just write the keystream
 230  *              to @dest@.
 231  */
 232
 233 #define CHACHA_ENCRYPT(r, ctx, src, dest, sz)                           \
 234   chacha##r##_encrypt(ctx, src, dest, sz)
 235 #define DEFENCRYPT(r)                                                   \
 236   void CHACHA_ENCRYPT(r, chacha_ctx *ctx, const void *src,              \
 237                       void *dest, size_t sz)                            \
 238   {                                                                     \
 239     chacha_matrix b;                                                    \
 240     const octet *s = src;                                               \
 241     octet *d = dest;                                                    \
 242     size_t n;                                                           \
 243     kludge64 pos, delta;                                                \
 244                                                                         \
 245     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 246     if (!sz) return;                                                    \
 247                                                                         \
 248     if (!dest) {                                                        \
 249       n = sz/CHACHA_OUTSZ;                                              \
 250       pos = chacha_tellu64(ctx);                                        \
 251       ASSIGN64(delta, n);                                               \
 252       ADD64(pos, pos, delta);                                           \
 253       chacha_seeku64(ctx, pos);                                         \
 254       sz = sz%CHACHA_OUTSZ;                                             \
 255     } else if (!src) {                                                  \
 256       while (sz >= CHACHA_OUTSZ) {                                      \
 257         core(r, ctx->a, b);                                             \
 258         CHACHA_STEP(ctx->a);                                            \
 259         SALSA20_GENFULL(b, d);                                          \
 260         sz -= CHACHA_OUTSZ;                                             \
 261       }                                                                 \
 262     } else {                                                            \
 263       while (sz >= CHACHA_OUTSZ) {                                      \
 264         core(r, ctx->a, b);                                             \
 265         CHACHA_STEP(ctx->a);                                            \
 266         SALSA20_MIXFULL(b, d, s);                                       \
 267         sz -= CHACHA_OUTSZ;                                             \
 268       }                                                                 \
 269     }                                                                   \
 270                                                                         \
 271     if (sz) {                                                           \
 272       core(r, ctx->a, b);                                               \
 273       CHACHA_STEP(ctx->a);                                              \
 274       SALSA20_PREPBUF(ctx, b);                                          \
 275       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 276       assert(!sz);                                                      \
 277     }                                                                   \
 278   }
 279 CHACHA_VARS(DEFENCRYPT)
 280
 281 /*----- HChaCha implementation --------------------------------------------*/
 282
 283 #define HCHACHA_RAW(r, ctx, src, dest) hchacha##r##_raw(ctx, src, dest)
 284 #define HCHACHA_PRF(r, ctx, src, dest) hchacha##r##_prf(ctx, src, dest)
 285
 286 /* --- @hchacha{20,12,8}_prf@ --- *
 287  *
 288  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 289  *              @const void *src@ = the input (@HCHACHA_INSZ@ bytes)
 290  *              @void *dest@ = the output (@HCHACHA_OUTSZ@ bytes)
 291  *
 292  * Returns:     ---
 293  *
 294  * Use:         Apply the HChacha/r pseudorandom function to @src@, writing
 295  *              the result to @out@.
 296  */
 297
 298 #define DEFHCHACHA(r)                                                   \
 299   static void HCHACHA_RAW(r, chacha_matrix k,                           \
 300                           const uint32 *src, uint32 *dest)              \
 301   {                                                                     \
 302     chacha_matrix a;                                                    \
 303     int i;                                                              \
 304                                                                         \
 305     /* --- HChaCha, computed from full ChaCha --- *                     \
 306      *                                                                  \
 307      * The security proof makes use of the fact that HChaCha (i.e.,     \
 308      * without the final feedforward step) can be computed from full    \
 309      * ChaCha using only knowledge of the non-secret input.  I don't    \
 310      * want to compromise the performance of the main function by       \
 311      * making the feedforward step separate, but this operation is less \
 312      * speed critical, so we do it the harder way.                      \
 313      */                                                                 \
 314                                                                         \
 315     for (i = 0; i < 4; i++) k[12 + i] = src[i];                         \
 316     core(r, k, a);                                                      \
 317     for (i = 0; i < 8; i++) dest[i] = a[(i + 4)^4] - k[(i + 4)^4];      \
 318   }                                                                     \
 319                                                                         \
 320   void HCHACHA_PRF(r, chacha_ctx *ctx, const void *src, void *dest)     \
 321   {                                                                     \
 322     const octet *s = src;                                               \
 323     octet *d = dest;                                                    \
 324     uint32 in[4], out[8];                                               \
 325     int i;                                                              \
 326                                                                         \
 327     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 328     HCHACHA_RAW(r, ctx->a, in, out);                                    \
 329     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 330   }
 331 CHACHA_VARS(DEFHCHACHA)
 332
 333 /*----- XChaCha implementation -------------------------------------------*/
 334
 335 /* --- Some convenient macros for naming functions --- *
 336  *
 337  * Because the crypto core is involved in XChaCha/r's per-nonce setup, we
 338  * need to take an interest in the number of rounds in most of the various
 339  * functions, and it will probably help if we distinguish the context
 340  * structures for the various versions.
 341  */
 342
 343 #define XCHACHA_CTX(r) xchacha##r##_ctx
 344 #define XCHACHA_INIT(r, ctx, k, ksz, n) xchacha##r##_init(ctx, k, ksz, n)
 345 #define XCHACHA_SETNONCE(r, ctx, n) xchacha##r##_setnonce(ctx, n)
 346 #define XCHACHA_SEEK(r, ctx, i) xchacha##r##_seek(ctx, i)
 347 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 348 #define XCHACHA_TELL(r, ctx) xchacha##r##_tell(ctx)
 349 #define XCHACHA_TELLU64(r, ctx) xchacha##r##_tellu64(ctx)
 350 #define XCHACHA_ENCRYPT(r, ctx, src, dest, sz)                          \
 351   xchacha##r##_encrypt(ctx, src, dest, sz)
 352
 353 /* --- @xchacha{20,12,8}_init@ --- *
 354  *
 355  * Arguments:   @xchachaR_ctx *ctx@ = the context to fill in
 356  *              @const void *key@ = pointer to key material
 357  *              @size_t ksz@ = size of key (either 32 or 16)
 358  *              @const void *nonce@ = initial nonce, or null
 359  *
 360  * Returns:     ---
 361  *
 362  * Use:         Initializes an XChaCha/r context ready for use.
 363  *
 364  *              There is a different function for each number of rounds,
 365  *              unlike for plain ChaCha.
 366  */
 367
 368 #define DEFXINIT(r)                                                     \
 369   void XCHACHA_INIT(r, XCHACHA_CTX(r) *ctx,                             \
 370                     const void *key, size_t ksz, const void *nonce)     \
 371   {                                                                     \
 372     static const octet zerononce[XCHACHA_NONCESZ];                      \
 373                                                                         \
 374     populate(ctx->k, key, ksz);                                         \
 375     ctx->s.a[ 0] = CHACHA_A256;                                         \
 376     ctx->s.a[ 1] = CHACHA_B256;                                         \
 377     ctx->s.a[ 2] = CHACHA_C256;                                         \
 378     ctx->s.a[ 3] = CHACHA_D256;                                         \
 379     XCHACHA_SETNONCE(r, ctx, nonce ? nonce : zerononce);                \
 380   }
 381 CHACHA_VARS(DEFXINIT)
 382
 383 /* --- @xchacha{20,12,8}_setnonce@ --- *
 384  *
 385  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 386  *              @const void *nonce@ = the nonce (@XCHACHA_NONCESZ@ bytes)
 387  *
 388  * Returns:     ---
 389  *
 390  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 391  *              different message.  The stream position is reset to zero (see
 392  *              @chacha_seek@ etc.).
 393  *
 394  *              There is a different function for each number of rounds,
 395  *              unlike for plain ChaCha.
 396  */
 397
 398 #define DEFXNONCE(r)                                                    \
 399   void XCHACHA_SETNONCE(r, XCHACHA_CTX(r) *ctx, const void *nonce)      \
 400   {                                                                     \
 401     const octet *n = nonce;                                             \
 402     uint32 in[4];                                                       \
 403     int i;                                                              \
 404                                                                         \
 405     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 406     HCHACHA_RAW(r, ctx->k, in, ctx->s.a + 4);                           \
 407     chacha_setnonce(&ctx->s, n + 16);                                   \
 408   }
 409 CHACHA_VARS(DEFXNONCE)
 410
 411 /* --- @xchacha{20,12,8}_seek@, @xchacha{20,12,8}_seeku64@ --- *
 412  *
 413  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 414  *              @unsigned long i@, @kludge64 i@ = new position to set
 415  *
 416  * Returns:     ---
 417  *
 418  * Use:         Sets a new stream position, in units of ChaCha output
 419  *              blocks, which are @XCHACHA_OUTSZ@ bytes each.  Byte
 420  *              granularity can be achieved by calling @xchachaR_encrypt@
 421  *              appropriately.
 422  *
 423  *              There is a different function for each number of rounds,
 424  *              unlike for plain ChaCha, because the context structures are
 425  *              different.
 426  */
 427
 428 /* --- @xchacha{20,12,8}_tell@, @xchacha{20,12,8}_tellu64@ --- *
 429  *
 430  * Arguments:   @chacha_ctx *ctx@ = pointer to context
 431  *
 432  * Returns:     The current position in the output stream, in blocks,
 433  *              rounding upwards.
 434  *
 435  *              There is a different function for each number of rounds,
 436  *              unlike for plain ChaCha, because the context structures are
 437  *              different.
 438  */
 439
 440 /* --- @xchacha{,12,8}_encrypt@ --- *
 441  *
 442  * Arguments:   @xchachaR_ctx *ctx@ = pointer to context
 443  *              @const void *src@ = source buffer (or null)
 444  *              @void *dest@ = destination buffer (or null)
 445  *              @size_t sz@ = size of the buffers
 446  *
 447  * Returns:     ---
 448  *
 449  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 450  *              XChaCha works by XORing plaintext with a keystream, so
 451  *              encryption and decryption are the same operation.  If @dest@
 452  *              is null then ignore @src@ and skip @sz@ bytes of the
 453  *              keystream.  If @src@ is null, then just write the keystream
 454  *              to @dest@.
 455  */
 456
 457 #define DEFXPASSTHRU(r)                                                 \
 458   void XCHACHA_SEEK(r, XCHACHA_CTX(r) *ctx, unsigned long i)            \
 459     { chacha_seek(&ctx->s, i); }                                        \
 460   void XCHACHA_SEEKU64(r, XCHACHA_CTX(r) *ctx, kludge64 i)              \
 461     { chacha_seeku64(&ctx->s, i); }                                     \
 462   unsigned long XCHACHA_TELL(r, XCHACHA_CTX(r) *ctx)                    \
 463     { return chacha_tell(&ctx->s); }                                    \
 464   kludge64 XCHACHA_TELLU64(r, XCHACHA_CTX(r) *ctx)                      \
 465     { return chacha_tellu64(&ctx->s); }                                 \
 466   void XCHACHA_ENCRYPT(r, XCHACHA_CTX(r) *ctx,                          \
 467                         const void *src, void *dest, size_t sz)         \
 468     { CHACHA_ENCRYPT(r, &ctx->s, src, dest, sz); }
 469 CHACHA_VARS(DEFXPASSTHRU)
 470
 471 /*----- Generic cipher interface ------------------------------------------*/
 472
 473 typedef struct gctx { gcipher c; chacha_ctx ctx; } gctx;
 474
 475 static void gsetiv(gcipher *c, const void *iv)
 476   { gctx *g = (gctx *)c; chacha_setnonce(&g->ctx, iv); }
 477
 478 static void gdestroy(gcipher *c)
 479   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 480
 481 #define DEFGCIPHER(r)                                                   \
 482                                                                         \
 483   static const gcipher_ops gops_##r;                                    \
 484                                                                         \
 485   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 486   {                                                                     \
 487     gctx *g = S_CREATE(gctx);                                           \
 488     g->c.ops = &gops_##r;                                               \
 489     chacha_init(&g->ctx, k, sz, 0);                                     \
 490     return (&g->c);                                                     \
 491   }                                                                     \
 492                                                                         \
 493   static void gencrypt_##r(gcipher *c, const void *s,                   \
 494                            void *t, size_t sz)                          \
 495     { gctx *g = (gctx *)c; CHACHA_ENCRYPT(r, &g->ctx, s, t, sz); }      \
 496                                                                         \
 497   static const gcipher_ops gops_##r = {                                 \
 498     &chacha##r,                                                         \
 499     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 500   };                                                                    \
 501                                                                         \
 502   const gccipher chacha##r = {                                          \
 503     "chacha" #r, chacha_keysz,                                          \
 504     CHACHA_NONCESZ, ginit_##r                                           \
 505   };
 506
 507 CHACHA_VARS(DEFGCIPHER)
 508
 509 #define DEFGXCIPHER(r)                                                  \
 510                                                                         \
 511   typedef struct { gcipher c; XCHACHA_CTX(r) ctx; } gxctx_##r;          \
 512                                                                         \
 513   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 514     { gxctx_##r *g = (gxctx_##r *)c; XCHACHA_SETNONCE(r, &g->ctx, iv); } \
 515                                                                         \
 516   static void gxdestroy_##r(gcipher *c)                                 \
 517     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 518                                                                         \
 519   static const gcipher_ops gxops_##r;                                   \
 520                                                                         \
 521   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 522   {                                                                     \
 523     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 524     g->c.ops = &gxops_##r;                                              \
 525     XCHACHA_INIT(r, &g->ctx, k, sz, 0);                                 \
 526     return (&g->c);                                                     \
 527   }                                                                     \
 528                                                                         \
 529   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 530                             void *t, size_t sz)                         \
 531   {                                                                     \
 532     gxctx_##r *g = (gxctx_##r *)c;                                      \
 533     XCHACHA_ENCRYPT(r, &g->ctx, s, t, sz);                              \
 534   }                                                                     \
 535                                                                         \
 536   static const gcipher_ops gxops_##r = {                                \
 537     &xchacha##r,                                                        \
 538     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 539   };                                                                    \
 540                                                                         \
 541   const gccipher xchacha##r = {                                         \
 542     "xchacha" #r, chacha_keysz,                                         \
 543     CHACHA_NONCESZ, gxinit_##r                                          \
 544   };
 545
 546 CHACHA_VARS(DEFGXCIPHER)
 547
 548 /*----- Generic random number generator interface -------------------------*/
 549
 550 typedef struct grops {
 551   size_t noncesz;
 552   void (*seek)(void *, kludge64);
 553   kludge64 (*tell)(void *);
 554   void (*setnonce)(void *, const void *);
 555   void (*generate)(void *, void *, size_t);
 556 } grops;
 557
 558 typedef struct grbasectx {
 559   grand r;
 560   const grops *ops;
 561 } grbasectx;
 562
 563 static int grmisc(grand *r, unsigned op, ...)
 564 {
 565   octet buf[XCHACHA_NONCESZ];
 566   grbasectx *g = (grbasectx *)r;
 567   grand *rr;
 568   const octet *p;
 569   size_t sz;
 570   uint32 i;
 571   unsigned long ul;
 572   kludge64 pos;
 573   va_list ap;
 574   int rc = 0;
 575
 576   va_start(ap, op);
 577
 578   switch (op) {
 579     case GRAND_CHECK:
 580       switch (va_arg(ap, unsigned)) {
 581         case GRAND_CHECK:
 582         case GRAND_SEEDINT:
 583         case GRAND_SEEDUINT32:
 584         case GRAND_SEEDBLOCK:
 585         case GRAND_SEEDRAND:
 586         case CHACHA_SEEK:
 587         case CHACHA_SEEKU64:
 588         case CHACHA_TELL:
 589         case CHACHA_TELLU64:
 590           rc = 1;
 591           break;
 592         default:
 593           rc = 0;
 594           break;
 595       }
 596       break;
 597
 598     case GRAND_SEEDINT:
 599       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 600       memset(buf + 4, 0, g->ops->noncesz - 4);
 601       g->ops->setnonce(g, buf);
 602       break;
 603     case GRAND_SEEDUINT32:
 604       i = va_arg(ap, uint32); STORE32_L(buf, i);
 605       memset(buf + 4, 0, g->ops->noncesz - 4);
 606       g->ops->setnonce(g, buf);
 607       break;
 608     case GRAND_SEEDBLOCK:
 609       p = va_arg(ap, const void *);
 610       sz = va_arg(ap, size_t);
 611       if (sz < g->ops->noncesz) {
 612         memcpy(buf, p, sz);
 613         memset(buf + sz, 0, g->ops->noncesz - sz);
 614         p = buf;
 615       }
 616       g->ops->setnonce(g, p);
 617       break;
 618     case GRAND_SEEDRAND:
 619       rr = va_arg(ap, grand *);
 620       rr->ops->fill(rr, buf, g->ops->noncesz);
 621       g->ops->setnonce(g, buf);
 622       break;
 623     case CHACHA_SEEK:
 624       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 625       g->ops->seek(g, pos);
 626       break;
 627     case CHACHA_SEEKU64:
 628       pos = va_arg(ap, kludge64);
 629       g->ops->seek(g, pos);
 630       break;
 631     case CHACHA_TELL:
 632       pos = g->ops->tell(g);
 633       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 634       break;
 635     case CHACHA_TELLU64:
 636       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 637       break;
 638     default:
 639       GRAND_BADOP;
 640       break;
 641   }
 642
 643   return (rc);
 644 }
 645
 646 static octet grbyte(grand *r)
 647 {
 648   grbasectx *g = (grbasectx *)r;
 649   octet o;
 650   g->ops->generate(g, &o, 1);
 651   return (o);
 652 }
 653
 654 static uint32 grword(grand *r)
 655 {
 656   grbasectx *g = (grbasectx *)r;
 657   octet b[4];
 658   g->ops->generate(g, b, sizeof(b));
 659   return (LOAD32_L(b));
 660 }
 661
 662 static void grfill(grand *r, void *p, size_t sz)
 663 {
 664   grbasectx *g = (grbasectx *)r;
 665   g->ops->generate(r, p, sz);
 666 }
 667
 668 typedef struct grctx {
 669   grbasectx r;
 670   chacha_ctx ctx;
 671 } grctx;
 672
 673 static void gr_seek(void *r, kludge64 pos)
 674   { grctx *g = r; chacha_seeku64(&g->ctx, pos); }
 675
 676 static kludge64 gr_tell(void *r)
 677   { grctx *g = r; return (chacha_tellu64(&g->ctx)); }
 678
 679 static void gr_setnonce(void *r, const void *n)
 680   { grctx *g = r; chacha_setnonce(&g->ctx, n); }
 681
 682 static void grdestroy(grand *r)
 683   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 684
 685 #define DEFGRAND(rr)                                                    \
 686                                                                         \
 687   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 688     { grctx *g = r; CHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }            \
 689                                                                         \
 690   static const grops grops_##rr =                                       \
 691     { CHACHA_NONCESZ, gr_seek, gr_tell,                                 \
 692       gr_setnonce, gr_generate_##rr };                                  \
 693                                                                         \
 694   static const grand_ops grops_rand_##rr = {                            \
 695     "chacha" #rr, GRAND_CRYPTO, 0,                                      \
 696     grmisc, grdestroy, grword,                                          \
 697     grbyte, grword, grand_range, grfill                                 \
 698   };                                                                    \
 699                                                                         \
 700   grand *chacha##rr##_rand(const void *k, size_t ksz, const void *n)    \
 701   {                                                                     \
 702     grctx *g = S_CREATE(g);                                             \
 703     g->r.r.ops = &grops_rand_##rr;                                      \
 704     g->r.ops = &grops_##rr;                                             \
 705     chacha_init(&g->ctx, k, ksz, n);                                    \
 706     return (&g->r.r);                                                   \
 707   }
 708 CHACHA_VARS(DEFGRAND)
 709
 710 #define DEFXGRAND(rr)                                                   \
 711                                                                         \
 712   typedef struct grxctx_##rr {                                          \
 713     grbasectx r;                                                        \
 714     XCHACHA_CTX(rr) ctx;                                                \
 715   } grxctx_##rr;                                                        \
 716                                                                         \
 717   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 718     { grxctx_##rr *g = r; XCHACHA_SEEKU64(rr, &g->ctx, pos); }          \
 719                                                                         \
 720   static kludge64 grx_tell_##rr(void *r)                                \
 721     { grxctx_##rr *g = r; return (XCHACHA_TELLU64(rr, &g->ctx)); }      \
 722                                                                         \
 723   static void grx_setnonce_##rr(void *r, const void *n)                 \
 724     { grxctx_##rr *g = r; XCHACHA_SETNONCE(rr, &g->ctx, n); }           \
 725                                                                         \
 726   static void grxdestroy_##rr(grand *r)                                 \
 727     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 728                                                                         \
 729   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 730     { grxctx_##rr *g = r; XCHACHA_ENCRYPT(rr, &g->ctx, 0, b, sz); }     \
 731                                                                         \
 732   static const grops grxops_##rr =                                      \
 733     { XCHACHA_NONCESZ, grx_seek_##rr, grx_tell_##rr,                    \
 734       grx_setnonce_##rr, grx_generate_##rr };                           \
 735                                                                         \
 736   static const grand_ops grxops_rand_##rr = {                           \
 737     "xchacha" #rr, GRAND_CRYPTO, 0,                                     \
 738     grmisc, grxdestroy_##rr, grword,                                    \
 739     grbyte, grword, grand_range, grfill                                 \
 740   };                                                                    \
 741                                                                         \
 742   grand *xchacha##rr##_rand(const void *k, size_t ksz, const void *n)   \
 743   {                                                                     \
 744     grxctx_##rr *g = S_CREATE(g);                                       \
 745     g->r.r.ops = &grxops_rand_##rr;                                     \
 746     g->r.ops = &grxops_##rr;                                            \
 747     XCHACHA_INIT(rr, &g->ctx, k, ksz, n);                               \
 748     return (&g->r.r);                                                   \
 749   }
 750 CHACHA_VARS(DEFXGRAND)
 751
 752 /*----- Test rig ----------------------------------------------------------*/
 753
 754 #ifdef TEST_RIG
 755
 756 #include <stdio.h>
 757 #include <string.h>
 758
 759 #include <mLib/quis.h>
 760 #include <mLib/testrig.h>
 761
 762 #define DEFVCORE(r)                                                     \
 763   static int v_core_##r(dstr *v)                                        \
 764   {                                                                     \
 765     chacha_matrix a, b;                                                 \
 766     dstr d = DSTR_INIT;                                                 \
 767     int i, n;                                                           \
 768     int ok = 1;                                                         \
 769                                                                         \
 770     DENSURE(&d, CHACHA_OUTSZ); d.len = CHACHA_OUTSZ;                    \
 771     n = *(int *)v[0].buf;                                               \
 772     for (i = 0; i < CHACHA_OUTSZ/4; i++)                                \
 773       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 774     for (i = 0; i < n; i++) {                                           \
 775       core(r, a, b);                                                    \
 776       memcpy(a, b, sizeof(a));                                          \
 777     }                                                                   \
 778     for (i = 0; i < CHACHA_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]);  \
 779                                                                         \
 780     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 781       ok = 0;                                                           \
 782       printf("\nfail core:"                                             \
 783              "\n\titerations = %d"                                      \
 784              "\n\tin       = ", n);                                     \
 785       type_hex.dump(&v[1], stdout);                                     \
 786       printf("\n\texpected   = ");                                      \
 787       type_hex.dump(&v[2], stdout);                                     \
 788       printf("\n\tcalculated = ");                                      \
 789       type_hex.dump(&d, stdout);                                        \
 790       putchar('\n');                                                    \
 791     }                                                                   \
 792                                                                         \
 793     dstr_destroy(&d);                                                   \
 794     return (ok);                                                        \
 795   }
 796 CHACHA_VARS(DEFVCORE)
 797
 798 #define CHACHA_CTX(r) chacha_ctx
 799 #define CHACHA_INIT(r, ctx, k, ksz, n) chacha_init(ctx, k, ksz, n)
 800 #define CHACHA_SEEKU64(r, ctx, i) chacha_seeku64(ctx, i)
 801 #define XCHACHA_SEEKU64(r, ctx, i) xchacha##r##_seeku64(ctx, i)
 802
 803 #define DEFxVENC(base, BASE, r)                                         \
 804   static int v_encrypt_##base##_##r(dstr *v)                            \
 805   {                                                                     \
 806     BASE##_CTX(r) ctx;                                                  \
 807     dstr d = DSTR_INIT;                                                 \
 808     kludge64 pos;                                                       \
 809     const octet *p, *p0;                                                \
 810     octet *q;                                                           \
 811     size_t sz, sz0, step;                                               \
 812     unsigned long skip;                                                 \
 813     int ok = 1;                                                         \
 814                                                                         \
 815     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 816     else { p0 = 0; sz0 = v[5].len; }                                    \
 817     DENSURE(&d, sz0); d.len = sz0;                                      \
 818     skip = *(unsigned long *)v[3].buf;                                  \
 819                                                                         \
 820     step = 0;                                                           \
 821     while (step < sz0 + skip) {                                         \
 822       step = step ? 3*step + 4 : 1;                                     \
 823       if (step > sz0 + skip) step = sz0 + skip;                         \
 824       BASE##_INIT(r, &ctx, v[0].buf, v[0].len, v[1].buf);               \
 825       if (v[2].len) {                                                   \
 826         LOAD64_(pos, v[2].buf);                                         \
 827         BASE##_SEEKU64(r, &ctx, pos);                                   \
 828       }                                                                 \
 829                                                                         \
 830       for (sz = skip; sz >= step; sz -= step)                           \
 831         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 832       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 833       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 834            sz >= step;                                                  \
 835            sz -= step, q += step) {                                     \
 836         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 837         if (p) p += step;                                               \
 838       }                                                                 \
 839       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 840                                                                         \
 841       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 842         ok = 0;                                                         \
 843         printf("\nfail encrypt:"                                        \
 844                "\n\tstep           = %lu"                               \
 845                "\n\tkey    = ", (unsigned long)step);                   \
 846         type_hex.dump(&v[0], stdout);                                   \
 847         printf("\n\tnonce          = ");                                \
 848         type_hex.dump(&v[1], stdout);                                   \
 849         printf("\n\tposition   = ");                                    \
 850         type_hex.dump(&v[2], stdout);                                   \
 851         printf("\n\tskip           = %lu", skip);                       \
 852         printf("\n\tmessage    = ");                                    \
 853         type_hex.dump(&v[4], stdout);                                   \
 854         printf("\n\texpected   = ");                                    \
 855         type_hex.dump(&v[5], stdout);                                   \
 856         printf("\n\tcalculated = ");                                    \
 857         type_hex.dump(&d, stdout);                                      \
 858         putchar('\n');                                                  \
 859       }                                                                 \
 860     }                                                                   \
 861                                                                         \
 862     dstr_destroy(&d);                                                   \
 863     return (ok);                                                        \
 864   }
 865 #define DEFVENC(r) DEFxVENC(chacha, CHACHA, r)
 866 #define DEFXVENC(r) DEFxVENC(xchacha, XCHACHA, r)
 867 CHACHA_VARS(DEFVENC)
 868 CHACHA_VARS(DEFXVENC)
 869
 870 static test_chunk defs[] = {
 871 #define DEFxTAB(base, r)                                                \
 872   { #base #r, v_encrypt_##base##_##r,                                   \
 873     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 874       &type_hex, &type_hex, 0 } },
 875 #define DEFTAB(r)                                                       \
 876   { "chacha" #r "-core", v_core_##r,                                    \
 877     { &type_int, &type_hex, &type_hex, 0 } },                           \
 878   DEFxTAB(chacha, r)
 879 #define DEFXTAB(r) DEFxTAB(xchacha, r)
 880 CHACHA_VARS(DEFTAB)
 881 CHACHA_VARS(DEFXTAB)
 882   { 0, 0, { 0 } }
 883 };
 884
 885 int main(int argc, char *argv[])
 886 {
 887   test_run(argc, argv, defs, SRCDIR"/t/chacha");
 888   return (0);
 889 }
 890
 891 #endif
 892
 893 /*----- That's all, folks -------------------------------------------------*/