chiark - git - mdw - catacomb/blob - symm/salsa20.c

   1 /* -*-c-*-
   2  *
   3  * Salsa20 stream cipher
   4  *
   5  * (c) 2015 Straylight/Edgeware
   6  */
   7
   8 /*----- Header files ------------------------------------------------------*/
   9
  10 #include <stdarg.h>
  11
  12 #include <mLib/bits.h>
  13
  14 #include "arena.h"
  15 #include "gcipher.h"
  16 #include "grand.h"
  17 #include "keysz.h"
  18 #include "paranoia.h"
  19 #include "salsa20.h"
  20 #include "salsa20-core.h"
  21
  22 /*----- Global variables --------------------------------------------------*/
  23
  24 const octet salsa20_keysz[] = { KSZ_SET, 32, 16, 10, 0 };
  25
  26 /*----- The Salsa20 core function and utilities ---------------------------*/
  27
  28 /* --- @core@ --- *
  29  *
  30  * Arguments:   @unsigned r@ = number of rounds
  31  *              @const salsa20_matrix src@ = input matrix
  32  *              @salsa20_matrix dest@ = where to put the output
  33  *
  34  * Returns:     ---
  35  *
  36  *
  37  * Use:         Apply the Salsa20/r core function to @src@, writing the
  38  *              result to @dest@.  This consists of @r@ rounds followed by
  39  *              the feedforward step.
  40  */
  41
  42 static void core(unsigned r, const salsa20_matrix src, salsa20_matrix dest)
  43   { SALSA20_nR(dest, src, r); SALSA20_FFWD(dest, src); }
  44
  45 /* --- @populate@ --- *
  46  *
  47  * Arguments:   @salsa20_matrix a@ = a matrix to fill in
  48  *              @const void *key@ = pointer to key material
  49  *              @size_t ksz@ = size of key
  50  *
  51  * Returns:     ---
  52  *
  53  * Use:         Fills in a Salsa20 matrix from the key, setting the
  54  *              appropriate constants according to the key length.  The nonce
  55  *              and position words are left uninitialized.
  56  */
  57
  58 static void populate(salsa20_matrix a, const void *key, size_t ksz)
  59 {
  60   const octet *k = key;
  61
  62   KSZ_ASSERT(salsa20, ksz);
  63
  64   a[ 1] = LOAD32_L(k +  0);
  65   a[ 2] = LOAD32_L(k +  4);
  66   if (ksz == 10) {
  67     a[ 3] = LOAD16_L(k +  8);
  68     a[ 4] = 0;
  69   } else {
  70     a[ 3] = LOAD32_L(k +  8);
  71     a[ 4] = LOAD32_L(k + 12);
  72   }
  73   if (ksz <= 16) {
  74     a[11] = a[ 1];
  75     a[12] = a[ 2];
  76     a[13] = a[ 3];
  77     a[14] = a[ 4];
  78     a[ 0] = SALSA20_A128;
  79     a[ 5] = SALSA20_B128;
  80     a[10] = ksz == 10 ? SALSA20_C80 : SALSA20_C128;
  81     a[15] = SALSA20_D128;
  82   } else {
  83     a[11] = LOAD32_L(k + 16);
  84     a[12] = LOAD32_L(k + 20);
  85     a[13] = LOAD32_L(k + 24);
  86     a[14] = LOAD32_L(k + 28);
  87     a[ 0] = SALSA20_A256;
  88     a[ 5] = SALSA20_B256;
  89     a[10] = SALSA20_C256;
  90     a[15] = SALSA20_D256;
  91   }
  92 }
  93
  94 /*----- Salsa20 implementation --------------------------------------------*/
  95
  96 /* --- @salsa20_init@ --- *
  97  *
  98  * Arguments:   @salsa20_ctx *ctx@ = context to fill in
  99  *              @const void *key@ = pointer to key material
 100  *              @size_t ksz@ = size of key (either 32 or 16)
 101  *              @const void *nonce@ = initial nonce, or null
 102  *
 103  * Returns:     ---
 104  *
 105  * Use:         Initializes a Salsa20 context ready for use.
 106  */
 107
 108 void salsa20_init(salsa20_ctx *ctx, const void *key, size_t ksz,
 109                   const void *nonce)
 110 {
 111   static const octet zerononce[SALSA20_NONCESZ];
 112
 113   populate(ctx->a, key, ksz);
 114   salsa20_setnonce(ctx, nonce ? nonce : zerononce);
 115 }
 116
 117 /* --- @salsa20_setnonce@ --- *
 118  *
 119  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 120  *              @const void *nonce@ = the nonce (@SALSA20_NONCESZ@ bytes)
 121  *
 122  * Returns:     ---
 123  *
 124  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 125  *              different message.  The stream position is reset to zero (see
 126  *              @salsa20_seek@ etc.).
 127  */
 128
 129 void salsa20_setnonce(salsa20_ctx *ctx, const void *nonce)
 130 {
 131   const octet *n = nonce;
 132
 133   ctx->a[6] = LOAD32_L(n + 0);
 134   ctx->a[7] = LOAD32_L(n + 4);
 135   salsa20_seek(ctx, 0);
 136 }
 137
 138 /* --- @salsa20_seek@, @salsa20_seeku64@ --- *
 139  *
 140  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 141  *              @unsigned long i@, @kludge64 i@ = new position to set
 142  *
 143  * Returns:     ---
 144  *
 145  * Use:         Sets a new stream position, in units of Salsa20 output
 146  *              blocks, which are @SALSA20_OUTSZ@ bytes each.  Byte
 147  *              granularity can be achieved by calling @salsa20R_encrypt@
 148  *              appropriately.
 149  */
 150
 151 void salsa20_seek(salsa20_ctx *ctx, unsigned long i)
 152   { kludge64 ii; ASSIGN64(ii, i); salsa20_seeku64(ctx, ii); }
 153
 154 void salsa20_seeku64(salsa20_ctx *ctx, kludge64 i)
 155 {
 156   ctx->a[8] = LO64(i); ctx->a[9] = HI64(i);
 157   ctx->bufi = SALSA20_OUTSZ;
 158 }
 159
 160 /* --- @salsa20_tell@, @salsa20_tellu64@ --- *
 161  *
 162  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 163  *
 164  * Returns:     The current position in the output stream, in blocks,
 165  *              rounding upwards.
 166  */
 167
 168 unsigned long salsa20_tell(salsa20_ctx *ctx)
 169   { kludge64 i = salsa20_tellu64(ctx); return (GET64(unsigned long, i)); }
 170
 171 kludge64 salsa20_tellu64(salsa20_ctx *ctx)
 172   { kludge64 i; SET64(i, ctx->a[9], ctx->a[8]); return (i); }
 173
 174 /* --- @salsa20{,12,8}_encrypt@ --- *
 175  *
 176  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 177  *              @const void *src@ = source buffer (or null)
 178  *              @void *dest@ = destination buffer (or null)
 179  *              @size_t sz@ = size of the buffers
 180  *
 181  * Returns:     ---
 182  *
 183  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 184  *              Salsa20 works by XORing plaintext with a keystream, so
 185  *              encryption and decryption are the same operation.  If @dest@
 186  *              is null then ignore @src@ and skip @sz@ bytes of the
 187  *              keystream.  If @src@ is null, then just write the keystream
 188  *              to @dest@.
 189  */
 190
 191 #define SALSA20_ENCRYPT(r, ctx, src, dest, sz)                          \
 192   SALSA20_DECOR(salsa20, r, _encrypt)(ctx, src, dest, sz)
 193 #define DEFENCRYPT(r)                                                   \
 194   void SALSA20_ENCRYPT(r, salsa20_ctx *ctx, const void *src,            \
 195                        void *dest, size_t sz)                           \
 196   {                                                                     \
 197     salsa20_matrix b;                                                   \
 198     const octet *s = src;                                               \
 199     octet *d = dest;                                                    \
 200     size_t n;                                                           \
 201     kludge64 pos, delta;                                                \
 202                                                                         \
 203     SALSA20_OUTBUF(ctx, d, s, sz);                                      \
 204     if (!sz) return;                                                    \
 205                                                                         \
 206     if (!dest) {                                                        \
 207       n = sz/SALSA20_OUTSZ;                                             \
 208       pos = salsa20_tellu64(ctx);                                       \
 209       ASSIGN64(delta, n);                                               \
 210       ADD64(pos, pos, delta);                                           \
 211       salsa20_seeku64(ctx, pos);                                        \
 212       sz = sz%SALSA20_OUTSZ;                                            \
 213     } else if (!src) {                                                  \
 214       while (sz >= SALSA20_OUTSZ) {                                     \
 215         core(r, ctx->a, b);                                             \
 216         SALSA20_STEP(ctx->a);                                           \
 217         SALSA20_GENFULL(b, d);                                          \
 218         sz -= SALSA20_OUTSZ;                                            \
 219       }                                                                 \
 220     } else {                                                            \
 221       while (sz >= SALSA20_OUTSZ) {                                     \
 222         core(r, ctx->a, b);                                             \
 223         SALSA20_STEP(ctx->a);                                           \
 224         SALSA20_MIXFULL(b, d, s);                                       \
 225         sz -= SALSA20_OUTSZ;                                            \
 226       }                                                                 \
 227     }                                                                   \
 228                                                                         \
 229     if (sz) {                                                           \
 230       core(r, ctx->a, b);                                               \
 231       SALSA20_STEP(ctx->a);                                             \
 232       SALSA20_PREPBUF(ctx, b);                                          \
 233       SALSA20_OUTBUF(ctx, d, s, sz);                                    \
 234       assert(!sz);                                                      \
 235     }                                                                   \
 236   }
 237 SALSA20_VARS(DEFENCRYPT)
 238
 239 /*----- HSalsa20 implementation -------------------------------------------*/
 240
 241 #define HSALSA20_RAW(r, ctx, src, dest)                                 \
 242   SALSA20_DECOR(hsalsa20, r, _raw)(ctx, src, dest)
 243 #define HSALSA20_PRF(r, ctx, src, dest)                                 \
 244   SALSA20_DECOR(hsalsa20, r, _prf)(ctx, src, dest)
 245
 246 /* --- @hsalsa20{,12,8}_prf@ --- *
 247  *
 248  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 249  *              @const void *src@ = the input (@HSALSA20_INSZ@ bytes)
 250  *              @void *dest@ = the output (@HSALSA20_OUTSZ@ bytes)
 251  *
 252  * Returns:     ---
 253  *
 254  * Use:         Apply the HSalsa20/r pseudorandom function to @src@, writing
 255  *              the result to @out@.
 256  */
 257
 258 #define DEFHSALSA20(r)                                                  \
 259   static void HSALSA20_RAW(r, salsa20_matrix k,                         \
 260                            const uint32 *src, uint32 *dest)             \
 261   {                                                                     \
 262     salsa20_matrix a;                                                   \
 263     int i;                                                              \
 264                                                                         \
 265     /* --- HSalsa20, computed from full Salsa20 --- *                   \
 266      *                                                                  \
 267      * The security proof makes use of the fact that HSalsa20 (i.e.,    \
 268      * without the final feedforward step) can be computed from full    \
 269      * Salsa20 using only knowledge of the non-secret input.  I don't   \
 270      * want to compromise the performance of the main function by       \
 271      * making the feedforward step separate, but this operation is less \
 272      * speed critical, so we do it the harder way.                      \
 273      */                                                                 \
 274                                                                         \
 275     for (i = 0; i < 4; i++) k[i + 6] = src[i];                          \
 276     core(r, k, a);                                                      \
 277     for (i = 0; i < 4; i++) dest[i] = a[5*i] - k[5*i];                  \
 278     for (i = 4; i < 8; i++) dest[i] = a[i + 2] - k[i + 2];              \
 279   }                                                                     \
 280                                                                         \
 281   void HSALSA20_PRF(r, salsa20_ctx *ctx, const void *src, void *dest)   \
 282   {                                                                     \
 283     const octet *s = src;                                               \
 284     octet *d = dest;                                                    \
 285     uint32 in[4], out[8];                                               \
 286     int i;                                                              \
 287                                                                         \
 288     for (i = 0; i < 4; i++) in[i] = LOAD32_L(s + 4*i);                  \
 289     HSALSA20_RAW(r, ctx->a, in, out);                                   \
 290     for (i = 0; i < 8; i++) STORE32_L(d + 4*i, out[i]);                 \
 291   }
 292 SALSA20_VARS(DEFHSALSA20)
 293
 294 /*----- XSalsa20 implementation -------------------------------------------*/
 295
 296 /* --- Some convenient macros for naming functions --- *
 297  *
 298  * Because the crypto core is involved in XSalsa20/r's per-nonce setup, we
 299  * need to take an interest in the number of rounds in most of the various
 300  * functions, and it will probably help if we distinguish the context
 301  * structures for the various versions.
 302  */
 303
 304 #define XSALSA20_CTX(r) SALSA20_DECOR(xsalsa20, r, _ctx)
 305 #define XSALSA20_INIT(r, ctx, k, ksz, n)                                \
 306   SALSA20_DECOR(xsalsa20, r, _init)(ctx, k, ksz, n)
 307 #define XSALSA20_SETNONCE(r, ctx, n)                                    \
 308   SALSA20_DECOR(xsalsa20, r, _setnonce)(ctx, n)
 309 #define XSALSA20_SEEK(r, ctx, i)                                        \
 310   SALSA20_DECOR(xsalsa20, r, _seek)(ctx, i)
 311 #define XSALSA20_SEEKU64(r, ctx, i)                                     \
 312   SALSA20_DECOR(xsalsa20, r, _seeku64)(ctx, i)
 313 #define XSALSA20_TELL(r, ctx)                                           \
 314   SALSA20_DECOR(xsalsa20, r, _tell)(ctx)
 315 #define XSALSA20_TELLU64(r, ctx)                                        \
 316   SALSA20_DECOR(xsalsa20, r, _tellu64)(ctx)
 317 #define XSALSA20_ENCRYPT(r, ctx, src, dest, sz)                         \
 318   SALSA20_DECOR(xsalsa20, r, _encrypt)(ctx, src, dest, sz)
 319
 320 /* --- @xsalsa20{,12,8}_init@ --- *
 321  *
 322  * Arguments:   @xsalsa20R_ctx *ctx@ = the context to fill in
 323  *              @const void *key@ = pointer to key material
 324  *              @size_t ksz@ = size of key (either 32 or 16)
 325  *              @const void *nonce@ = initial nonce, or null
 326  *
 327  * Returns:     ---
 328  *
 329  * Use:         Initializes an XSalsa20/r context ready for use.
 330  *
 331  *              There is a different function for each number of rounds,
 332  *              unlike for plain Salsa20.
 333  */
 334
 335 #define DEFXINIT(r)                                                     \
 336   void XSALSA20_INIT(r, XSALSA20_CTX(r) *ctx,                           \
 337                         const void *key, size_t ksz, const void *nonce) \
 338   {                                                                     \
 339     static const octet zerononce[XSALSA20_NONCESZ];                     \
 340                                                                         \
 341     populate(ctx->k, key, ksz);                                         \
 342     ctx->s.a[ 0] = SALSA20_A256;                                        \
 343     ctx->s.a[ 5] = SALSA20_B256;                                        \
 344     ctx->s.a[10] = SALSA20_C256;                                        \
 345     ctx->s.a[15] = SALSA20_D256;                                        \
 346     XSALSA20_SETNONCE(r, ctx, nonce ? nonce : zerononce);               \
 347   }
 348 SALSA20_VARS(DEFXINIT)
 349
 350 /* --- @xsalsa20{,12,8}_setnonce@ --- *
 351  *
 352  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 353  *              @const void *nonce@ = the nonce (@XSALSA20_NONCESZ@ bytes)
 354  *
 355  * Returns:     ---
 356  *
 357  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 358  *              different message.  The stream position is reset to zero (see
 359  *              @salsa20_seek@ etc.).
 360  *
 361  *              There is a different function for each number of rounds,
 362  *              unlike for plain Salsa20.
 363  */
 364
 365 #define DEFXNONCE(r)                                                    \
 366   void XSALSA20_SETNONCE(r, XSALSA20_CTX(r) *ctx, const void *nonce)    \
 367   {                                                                     \
 368     const octet *n = nonce;                                             \
 369     uint32 in[4], out[8];                                               \
 370     int i;                                                              \
 371                                                                         \
 372     for (i = 0; i < 4; i++) in[i] = LOAD32_L(n + 4*i);                  \
 373     HSALSA20_RAW(r, ctx->k, in, out);                                   \
 374     for (i = 0; i < 4; i++) ctx->s.a[i + 1] = out[i];                   \
 375     for (i = 4; i < 8; i++) ctx->s.a[i + 7] = out[i];                   \
 376     salsa20_setnonce(&ctx->s, n + 16);                                  \
 377   }
 378 SALSA20_VARS(DEFXNONCE)
 379
 380 /* --- @xsalsa20{,12,8}_seek@, @xsalsa20{,12,8}_seeku64@ --- *
 381  *
 382  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 383  *              @unsigned long i@, @kludge64 i@ = new position to set
 384  *
 385  * Returns:     ---
 386  *
 387  * Use:         Sets a new stream position, in units of Salsa20 output
 388  *              blocks, which are @XSALSA20_OUTSZ@ bytes each.  Byte
 389  *              granularity can be achieved by calling @xsalsa20R_encrypt@
 390  *              appropriately.
 391  *
 392  *              There is a different function for each number of rounds,
 393  *              unlike for plain Salsa20, because the context structures are
 394  *              different.
 395  */
 396
 397 /* --- @xsalsa20{,12,8}_tell@, @xsalsa20{,12,8}_tellu64@ --- *
 398  *
 399  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 400  *
 401  * Returns:     The current position in the output stream, in blocks,
 402  *              rounding upwards.
 403  *
 404  *              There is a different function for each number of rounds,
 405  *              unlike for plain Salsa20, because the context structures are
 406  *              different.
 407  */
 408
 409 /* --- @xsalsa20{,12,8}_encrypt@ --- *
 410  *
 411  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 412  *              @const void *src@ = source buffer (or null)
 413  *              @void *dest@ = destination buffer (or null)
 414  *              @size_t sz@ = size of the buffers
 415  *
 416  * Returns:     ---
 417  *
 418  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 419  *              XSalsa20 works by XORing plaintext with a keystream, so
 420  *              encryption and decryption are the same operation.  If @dest@
 421  *              is null then ignore @src@ and skip @sz@ bytes of the
 422  *              keystream.  If @src@ is null, then just write the keystream
 423  *              to @dest@.
 424  */
 425
 426 #define DEFXPASSTHRU(r)                                                 \
 427   void XSALSA20_SEEK(r, XSALSA20_CTX(r) *ctx, unsigned long i)          \
 428     { salsa20_seek(&ctx->s, i); }                                       \
 429   void XSALSA20_SEEKU64(r, XSALSA20_CTX(r) *ctx, kludge64 i)            \
 430     { salsa20_seeku64(&ctx->s, i); }                                    \
 431   unsigned long XSALSA20_TELL(r, XSALSA20_CTX(r) *ctx)                  \
 432     { return salsa20_tell(&ctx->s); }                                   \
 433   kludge64 XSALSA20_TELLU64(r, XSALSA20_CTX(r) *ctx)                    \
 434     { return salsa20_tellu64(&ctx->s); }                                \
 435   void XSALSA20_ENCRYPT(r, XSALSA20_CTX(r) *ctx,                        \
 436                         const void *src, void *dest, size_t sz)         \
 437     { SALSA20_ENCRYPT(r, &ctx->s, src, dest, sz); }
 438 SALSA20_VARS(DEFXPASSTHRU)
 439
 440 /*----- Generic cipher interface ------------------------------------------*/
 441
 442 typedef struct gctx { gcipher c; salsa20_ctx ctx; } gctx;
 443
 444 static void gsetiv(gcipher *c, const void *iv)
 445   { gctx *g = (gctx *)c; salsa20_setnonce(&g->ctx, iv); }
 446
 447 static void gdestroy(gcipher *c)
 448   { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }
 449
 450 #define DEFGCIPHER(r)                                                   \
 451                                                                         \
 452   static const gcipher_ops gops_##r;                                    \
 453                                                                         \
 454   static gcipher *ginit_##r(const void *k, size_t sz)                   \
 455   {                                                                     \
 456     gctx *g = S_CREATE(gctx);                                           \
 457     g->c.ops = &gops_##r;                                               \
 458     salsa20_init(&g->ctx, k, sz, 0);                                    \
 459     return (&g->c);                                                     \
 460   }                                                                     \
 461                                                                         \
 462   static void gencrypt_##r(gcipher *c, const void *s,                   \
 463                            void *t, size_t sz)                          \
 464     { gctx *g = (gctx *)c; SALSA20_ENCRYPT(r, &g->ctx, s, t, sz); }     \
 465                                                                         \
 466   static const gcipher_ops gops_##r = {                                 \
 467     &SALSA20_DECOR(salsa20, r, ),                                       \
 468     gencrypt_##r, gencrypt_##r, gdestroy, gsetiv, 0                     \
 469   };                                                                    \
 470                                                                         \
 471   const gccipher SALSA20_DECOR(salsa20, r, ) = {                        \
 472     SALSA20_NAME_##r, salsa20_keysz,                                    \
 473     SALSA20_NONCESZ, ginit_##r                                          \
 474   };
 475
 476 SALSA20_VARS(DEFGCIPHER)
 477
 478 #define DEFGXCIPHER(r)                                                  \
 479                                                                         \
 480   typedef struct { gcipher c; XSALSA20_CTX(r) ctx; } gxctx_##r;         \
 481                                                                         \
 482   static void gxsetiv_##r(gcipher *c, const void *iv)                   \
 483     { gxctx_##r *g = (gxctx_##r *)c; XSALSA20_SETNONCE(r, &g->ctx, iv); } \
 484                                                                         \
 485   static void gxdestroy_##r(gcipher *c)                                 \
 486     { gxctx_##r *g = (gxctx_##r *)c; BURN(*g); S_DESTROY(g); }          \
 487                                                                         \
 488   static const gcipher_ops gxops_##r;                                   \
 489                                                                         \
 490   static gcipher *gxinit_##r(const void *k, size_t sz)                  \
 491   {                                                                     \
 492     gxctx_##r *g = S_CREATE(gxctx_##r);                                 \
 493     g->c.ops = &gxops_##r;                                              \
 494     XSALSA20_INIT(r, &g->ctx, k, sz, 0);                                \
 495     return (&g->c);                                                     \
 496   }                                                                     \
 497                                                                         \
 498   static void gxencrypt_##r(gcipher *c, const void *s,                  \
 499                             void *t, size_t sz)                         \
 500   {                                                                     \
 501     gxctx_##r *g = (gxctx_##r *)c;                                      \
 502     XSALSA20_ENCRYPT(r, &g->ctx, s, t, sz);                             \
 503   }                                                                     \
 504                                                                         \
 505   static const gcipher_ops gxops_##r = {                                \
 506     &SALSA20_DECOR(xsalsa20, r, ),                                      \
 507     gxencrypt_##r, gxencrypt_##r, gxdestroy_##r, gxsetiv_##r, 0         \
 508   };                                                                    \
 509                                                                         \
 510   const gccipher SALSA20_DECOR(xsalsa20, r, ) = {                       \
 511     "x" SALSA20_NAME_##r, salsa20_keysz,                                \
 512     XSALSA20_NONCESZ, gxinit_##r                                        \
 513   };
 514
 515 SALSA20_VARS(DEFGXCIPHER)
 516
 517 /*----- Generic random number generator interface -------------------------*/
 518
 519 typedef struct grops {
 520   size_t noncesz;
 521   void (*seek)(void *, kludge64);
 522   kludge64 (*tell)(void *);
 523   void (*setnonce)(void *, const void *);
 524   void (*generate)(void *, void *, size_t);
 525 } grops;
 526
 527 typedef struct grbasectx {
 528   grand r;
 529   const grops *ops;
 530 } grbasectx;
 531
 532 static int grmisc(grand *r, unsigned op, ...)
 533 {
 534   octet buf[XSALSA20_NONCESZ];
 535   grbasectx *g = (grbasectx *)r;
 536   grand *rr;
 537   const octet *p;
 538   size_t sz;
 539   uint32 i;
 540   unsigned long ul;
 541   kludge64 pos;
 542   va_list ap;
 543   int rc = 0;
 544
 545   va_start(ap, op);
 546
 547   switch (op) {
 548     case GRAND_CHECK:
 549       switch (va_arg(ap, unsigned)) {
 550         case GRAND_CHECK:
 551         case GRAND_SEEDINT:
 552         case GRAND_SEEDUINT32:
 553         case GRAND_SEEDBLOCK:
 554         case GRAND_SEEDRAND:
 555         case SALSA20_SEEK:
 556         case SALSA20_SEEKU64:
 557         case SALSA20_TELL:
 558         case SALSA20_TELLU64:
 559           rc = 1;
 560           break;
 561         default:
 562           rc = 0;
 563           break;
 564       }
 565       break;
 566
 567     case GRAND_SEEDINT:
 568       i = va_arg(ap, unsigned); STORE32_L(buf, i);
 569       memset(buf + 4, 0, g->ops->noncesz - 4);
 570       g->ops->setnonce(g, buf);
 571       break;
 572     case GRAND_SEEDUINT32:
 573       i = va_arg(ap, uint32); STORE32_L(buf, i);
 574       memset(buf + 4, 0, g->ops->noncesz - 4);
 575       g->ops->setnonce(g, buf);
 576       break;
 577     case GRAND_SEEDBLOCK:
 578       p = va_arg(ap, const void *);
 579       sz = va_arg(ap, size_t);
 580       if (sz < g->ops->noncesz) {
 581         memcpy(buf, p, sz);
 582         memset(buf + sz, 0, g->ops->noncesz - sz);
 583         p = buf;
 584       }
 585       g->ops->setnonce(g, p);
 586       break;
 587     case GRAND_SEEDRAND:
 588       rr = va_arg(ap, grand *);
 589       rr->ops->fill(rr, buf, g->ops->noncesz);
 590       g->ops->setnonce(g, buf);
 591       break;
 592     case SALSA20_SEEK:
 593       ul = va_arg(ap, unsigned long); ASSIGN64(pos, ul);
 594       g->ops->seek(g, pos);
 595       break;
 596     case SALSA20_SEEKU64:
 597       pos = va_arg(ap, kludge64);
 598       g->ops->seek(g, pos);
 599       break;
 600     case SALSA20_TELL:
 601       pos = g->ops->tell(g);
 602       *va_arg(ap, unsigned long *) = GET64(unsigned long, pos);
 603       break;
 604     case SALSA20_TELLU64:
 605       *va_arg(ap, kludge64 *) = g->ops->tell(g);
 606       break;
 607     default:
 608       GRAND_BADOP;
 609       break;
 610   }
 611
 612   return (rc);
 613 }
 614
 615 static octet grbyte(grand *r)
 616 {
 617   grbasectx *g = (grbasectx *)r;
 618   octet o;
 619   g->ops->generate(g, &o, 1);
 620   return (o);
 621 }
 622
 623 static uint32 grword(grand *r)
 624 {
 625   grbasectx *g = (grbasectx *)r;
 626   octet b[4];
 627   g->ops->generate(g, b, sizeof(b));
 628   return (LOAD32_L(b));
 629 }
 630
 631 static void grfill(grand *r, void *p, size_t sz)
 632 {
 633   grbasectx *g = (grbasectx *)r;
 634   g->ops->generate(r, p, sz);
 635 }
 636
 637 typedef struct grctx {
 638   grbasectx r;
 639   salsa20_ctx ctx;
 640 } grctx;
 641
 642 static void gr_seek(void *r, kludge64 pos)
 643   { grctx *g = r; salsa20_seeku64(&g->ctx, pos); }
 644
 645 static kludge64 gr_tell(void *r)
 646   { grctx *g = r; return (salsa20_tellu64(&g->ctx)); }
 647
 648 static void gr_setnonce(void *r, const void *n)
 649   { grctx *g = r; salsa20_setnonce(&g->ctx, n); }
 650
 651 static void grdestroy(grand *r)
 652   { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }
 653
 654 #define DEFGRAND(rr)                                                    \
 655                                                                         \
 656   static void gr_generate_##rr(void *r, void *b, size_t sz)             \
 657     { grctx *g = r; SALSA20_ENCRYPT(rr, &g->ctx, 0, b, sz); }           \
 658                                                                         \
 659   static const grops grops_##rr =                                       \
 660     { SALSA20_NONCESZ, gr_seek, gr_tell,                                \
 661       gr_setnonce, gr_generate_##rr };                                  \
 662                                                                         \
 663   static const grand_ops grops_rand_##rr = {                            \
 664     SALSA20_NAME_##rr, GRAND_CRYPTO, 0,                                 \
 665     grmisc, grdestroy, grword,                                          \
 666     grbyte, grword, grand_range, grfill                                 \
 667   };                                                                    \
 668                                                                         \
 669   grand *SALSA20_DECOR(salsa20, rr, _rand)                              \
 670     (const void *k, size_t ksz, const void *n)                          \
 671   {                                                                     \
 672     grctx *g = S_CREATE(g);                                             \
 673     g->r.r.ops = &grops_rand_##rr;                                      \
 674     g->r.ops = &grops_##rr;                                             \
 675     salsa20_init(&g->ctx, k, ksz, n);                                   \
 676     return (&g->r.r);                                                   \
 677   }
 678 SALSA20_VARS(DEFGRAND)
 679
 680 #define DEFXGRAND(rr)                                                   \
 681                                                                         \
 682   typedef struct grxctx_##rr {                                          \
 683     grbasectx r;                                                        \
 684     XSALSA20_CTX(rr) ctx;                                               \
 685   } grxctx_##rr;                                                        \
 686                                                                         \
 687   static void grx_seek_##rr(void *r, kludge64 pos)                      \
 688     { grxctx_##rr *g = r; XSALSA20_SEEKU64(rr, &g->ctx, pos); }         \
 689                                                                         \
 690   static kludge64 grx_tell_##rr(void *r)                                \
 691     { grxctx_##rr *g = r; return (XSALSA20_TELLU64(rr, &g->ctx)); }     \
 692                                                                         \
 693   static void grx_setnonce_##rr(void *r, const void *n)                 \
 694     { grxctx_##rr *g = r; XSALSA20_SETNONCE(rr, &g->ctx, n); }          \
 695                                                                         \
 696   static void grxdestroy_##rr(grand *r)                                 \
 697     { grxctx_##rr *g = (grxctx_##rr *)r; BURN(*g); S_DESTROY(g); }      \
 698                                                                         \
 699   static void grx_generate_##rr(void *r, void *b, size_t sz)            \
 700     { grxctx_##rr *g = r; XSALSA20_ENCRYPT(rr, &g->ctx, 0, b, sz); }    \
 701                                                                         \
 702   static const grops grxops_##rr =                                      \
 703   { XSALSA20_NONCESZ, grx_seek_##rr, grx_tell_##rr,                     \
 704       grx_setnonce_##rr, grx_generate_##rr };                           \
 705                                                                         \
 706   static const grand_ops grxops_rand_##rr = {                           \
 707     "x" SALSA20_NAME_##rr, GRAND_CRYPTO, 0,                             \
 708     grmisc, grxdestroy_##rr, grword,                                    \
 709     grbyte, grword, grand_range, grfill                                 \
 710   };                                                                    \
 711                                                                         \
 712   grand *SALSA20_DECOR(xsalsa20, rr, _rand)                             \
 713     (const void *k, size_t ksz, const void *n)                          \
 714   {                                                                     \
 715     grxctx_##rr *g = S_CREATE(g);                                       \
 716     g->r.r.ops = &grxops_rand_##rr;                                     \
 717     g->r.ops = &grxops_##rr;                                            \
 718     XSALSA20_INIT(rr, &g->ctx, k, ksz, n);                              \
 719     return (&g->r.r);                                                   \
 720   }
 721 SALSA20_VARS(DEFXGRAND)
 722
 723 /*----- Test rig ----------------------------------------------------------*/
 724
 725 #ifdef TEST_RIG
 726
 727 #include <stdio.h>
 728 #include <string.h>
 729
 730 #include <mLib/quis.h>
 731 #include <mLib/testrig.h>
 732
 733 #define DEFVCORE(r)                                                     \
 734   static int v_core_##r(dstr *v)                                        \
 735   {                                                                     \
 736     salsa20_matrix a, b;                                                \
 737     dstr d = DSTR_INIT;                                                 \
 738     int i, n;                                                           \
 739     int ok = 1;                                                         \
 740                                                                         \
 741     DENSURE(&d, SALSA20_OUTSZ); d.len = SALSA20_OUTSZ;                  \
 742     n = *(int *)v[0].buf;                                               \
 743     for (i = 0; i < SALSA20_OUTSZ/4; i++)                               \
 744       a[i] = LOAD32_L(v[1].buf + 4*i);                                  \
 745     for (i = 0; i < n; i++) {                                           \
 746       core(r, a, b);                                                    \
 747       memcpy(a, b, sizeof(a));                                          \
 748     }                                                                   \
 749     for (i = 0; i < SALSA20_OUTSZ/4; i++) STORE32_L(d.buf + 4*i, a[i]); \
 750                                                                         \
 751     if (d.len != v[2].len || memcmp(d.buf, v[2].buf, v[2].len) != 0) {  \
 752       ok = 0;                                                           \
 753       printf("\nfail core:"                                             \
 754              "\n\titerations = %d"                                      \
 755              "\n\tin       = ", n);                                     \
 756       type_hex.dump(&v[1], stdout);                                     \
 757       printf("\n\texpected   = ");                                      \
 758       type_hex.dump(&v[2], stdout);                                     \
 759       printf("\n\tcalculated = ");                                      \
 760       type_hex.dump(&d, stdout);                                        \
 761       putchar('\n');                                                    \
 762     }                                                                   \
 763                                                                         \
 764     dstr_destroy(&d);                                                   \
 765     return (ok);                                                        \
 766   }
 767 SALSA20_VARS(DEFVCORE)
 768
 769 #define SALSA20_CTX(r) salsa20_ctx
 770 #define SALSA20_INIT(r, ctx, k, ksz, n) salsa20_init(ctx, k, ksz, n)
 771 #define SALSA20_SEEKU64(r, ctx, i) salsa20_seeku64(ctx, i)
 772
 773 #define DEFxVENC(base, BASE, r)                                         \
 774   static int v_encrypt_##base##_##r(dstr *v)                            \
 775   {                                                                     \
 776     BASE##_CTX(r) ctx;                                                  \
 777     dstr d = DSTR_INIT;                                                 \
 778     kludge64 pos;                                                       \
 779     const octet *p, *p0;                                                \
 780     octet *q;                                                           \
 781     size_t sz, sz0, step;                                               \
 782     unsigned long skip;                                                 \
 783     int ok = 1;                                                         \
 784                                                                         \
 785     if (v[4].len) { p0 = (const octet *)v[4].buf; sz0 = v[4].len; }     \
 786     else { p0 = 0; sz0 = v[5].len; }                                    \
 787     DENSURE(&d, sz0); d.len = sz0;                                      \
 788     skip = *(unsigned long *)v[3].buf;                                  \
 789                                                                         \
 790     step = 0;                                                           \
 791     while (step < sz0 + skip) {                                         \
 792       step = step ? 3*step + 4 : 1;                                     \
 793       if (step > sz0 + skip) step = sz0 + skip;                         \
 794       BASE##_INIT(r, &ctx, v[0].buf, v[0].len, v[1].buf);               \
 795       if (v[2].len) {                                                   \
 796         LOAD64_(pos, v[2].buf);                                         \
 797         BASE##_SEEKU64(r, &ctx, pos);                                   \
 798       }                                                                 \
 799                                                                         \
 800       for (sz = skip; sz >= step; sz -= step)                           \
 801         BASE##_ENCRYPT(r, &ctx, 0, 0, step);                            \
 802       if (sz) BASE##_ENCRYPT(r, &ctx, 0, 0, sz);                        \
 803       for (p = p0, q = (octet *)d.buf, sz = sz0;                        \
 804            sz >= step;                                                  \
 805            sz -= step, q += step) {                                     \
 806         BASE##_ENCRYPT(r, &ctx, p, q, step);                            \
 807         if (p) p += step;                                               \
 808       }                                                                 \
 809       if (sz) BASE##_ENCRYPT(r, &ctx, p, q, sz);                        \
 810                                                                         \
 811       if (d.len != v[5].len || memcmp(d.buf, v[5].buf, v[5].len) != 0) { \
 812         ok = 0;                                                         \
 813         printf("\nfail encrypt:"                                        \
 814                "\n\tstep           = %lu"                               \
 815                "\n\tkey    = ", (unsigned long)step);                   \
 816         type_hex.dump(&v[0], stdout);                                   \
 817         printf("\n\tnonce          = ");                                \
 818         type_hex.dump(&v[1], stdout);                                   \
 819         printf("\n\tposition   = ");                                    \
 820         type_hex.dump(&v[2], stdout);                                   \
 821         printf("\n\tskip           = %lu", skip);                       \
 822         printf("\n\tmessage    = ");                                    \
 823         type_hex.dump(&v[4], stdout);                                   \
 824         printf("\n\texpected   = ");                                    \
 825         type_hex.dump(&v[5], stdout);                                   \
 826         printf("\n\tcalculated = ");                                    \
 827         type_hex.dump(&d, stdout);                                      \
 828         putchar('\n');                                                  \
 829       }                                                                 \
 830     }                                                                   \
 831                                                                         \
 832     dstr_destroy(&d);                                                   \
 833     return (ok);                                                        \
 834   }
 835 #define DEFVENC(r) DEFxVENC(salsa20, SALSA20, r)
 836 #define DEFXVENC(r) DEFxVENC(xsalsa20, XSALSA20, r)
 837 SALSA20_VARS(DEFVENC)
 838 SALSA20_VARS(DEFXVENC)
 839
 840 static test_chunk defs[] = {
 841 #define DEFxTAB(pre, base, r)                                           \
 842   { pre SALSA20_NAME_##r, v_encrypt_##base##_##r,                       \
 843     { &type_hex, &type_hex, &type_hex, &type_ulong,                     \
 844       &type_hex, &type_hex, 0 } },
 845 #define DEFTAB(r)                                                       \
 846   { SALSA20_NAME_##r "-core", v_core_##r,                               \
 847     { &type_int, &type_hex, &type_hex, 0 } },                           \
 848   DEFxTAB("", salsa20, r)
 849 #define DEFXTAB(r) DEFxTAB("x", xsalsa20, r)
 850 SALSA20_VARS(DEFTAB)
 851 SALSA20_VARS(DEFXTAB)
 852   { 0, 0, { 0 } }
 853 };
 854
 855 int main(int argc, char *argv[])
 856 {
 857   test_run(argc, argv, defs, SRCDIR"/t/salsa20");
 858   return (0);
 859 }
 860
 861 #endif
 862
 863 /*----- That's all, folks -------------------------------------------------*/