X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/rand.c

diff --git a/rand.c b/rand.c
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+++ /dev/null
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-/* -*-c-*-
- *
- * $Id$
- *
- * Secure random number generator
- *
- * (c) 1998 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <stdarg.h>
-#include <stdio.h>
-#include <string.h>
-
-#include <mLib/bits.h>
-#include <mLib/sub.h>
-
-#include "arena.h"
-#include "blowfish-cbc.h"
-#include "paranoia.h"
-#include "rand.h"
-#include "rmd160.h"
-#include "rmd160-hmac.h"
-
-/*----- Static variables --------------------------------------------------*/
-
-static const grand_ops gops;
-
-typedef struct gctx {
-  grand r;
-  rand_pool p;
-} gctx;
-
-static gctx *pool = 0;			/* Default random pool */
-
-/*----- Macros ------------------------------------------------------------*/
-
-#define RAND_RESOLVE(r) do {						\
-  if ((r) == RAND_GLOBAL) {						\
-    if (!pool)								\
-      pool = (gctx *)rand_create();					\
-    (r) = &pool->p;							\
-  }									\
-} while (0)
-
-#define TIMER(r) do {							\
-  if ((r)->s && (r)->s->timer)						\
-    (r)->s->timer(r);							\
-} while (0)
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @rand_init@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *
- * Returns:	---
- *
- * Use:		Initializes a randomness pool.  The pool doesn't start out
- *		very random: that's your job to sort out.  A good suggestion
- *		would be to attach an appropriate noise source and call
- *		@rand_seed@.
- */
-
-void rand_init(rand_pool *r)
-{
-  RAND_RESOLVE(r);
-  memset(r->pool, 0, sizeof(r->pool));
-  memset(r->buf, 0, sizeof(r->buf));
-  r->i = 0;
-  r->irot = 0;
-  r->ibits = r->obits = 0;
-  r->o = RAND_SECSZ;
-  r->s = 0;
-  rmd160_hmacinit(&r->k, 0, 0);
-  rand_gate(r);
-}
-
-/* --- @rand_noisesrc@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@const rand_source *s@ = pointer to source definition
- *
- * Returns:	---
- *
- * Use:		Sets a noise source for a randomness pool.  When the pool's
- *		estimate of good random bits falls to zero, the @getnoise@
- *		function is called, passing the pool handle as an argument.
- *		It is expected to increase the number of good bits by at
- *		least one, because it'll be called over and over again until
- *		there are enough bits to satisfy the caller.  The @timer@
- *		function is called frequently throughout the generator's
- *		operation.
- */
-
-void rand_noisesrc(rand_pool *r, const rand_source *s)
-{
-  RAND_RESOLVE(r);
-  r->s = s;
-}
-
-/* --- @rand_seed@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@unsigned bits@ = number of bits to ensure
- *
- * Returns:	---
- *
- * Use:		Ensures that there are at least @bits@ good bits of entropy
- *		in the pool.  It is recommended that you call this after
- *		initializing a new pool.  Requesting @bits > RAND_IBITS@ is
- *		doomed to failure (and is an error).
- */
-
-void rand_seed(rand_pool *r, unsigned bits)
-{
-  RAND_RESOLVE(r);
-
-  assert(((void)"bits pointlessly large in rand_seed", bits <= RAND_IBITS));
-  assert(((void)"no noise source in rand_seed", r->s));
-
-  while (r->ibits < bits)
-    r->s->getnoise(r);
-  rand_gate(r);
-}
-
-/* --- @rand_key@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@const void *k@ = pointer to key data
- *		@size_t sz@ = size of key data
- *
- * Returns:	---
- *
- * Use:		Sets the secret key for a randomness pool.  The key is used
- *		when mixing in new random bits.
- */
-
-void rand_key(rand_pool *r, const void *k, size_t sz)
-{
-  RAND_RESOLVE(r);
-  rmd160_hmacinit(&r->k, k, sz);
-}
-
-/* --- @rand_add@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@const void *p@ = pointer a buffer of data to add
- *		@size_t sz@ = size of the data buffer
- *		@unsigned goodbits@ = number of good bits estimated in buffer
- *
- * Returns:	---
- *
- * Use:		Mixes the data in the buffer with the contents of the
- *		pool.  The estimate of the number of good bits is added to
- *		the pool's own count.  The mixing operation is not
- *		cryptographically strong.  However, data in the input pool
- *		isn't output directly, only through the one-way gating
- *		operation, so that shouldn't matter.
- */
-
-void rand_add(rand_pool *r, const void *p, size_t sz, unsigned goodbits)
-{
-  const octet *c = p;
-  int i, rot;
-
-#if RAND_POOLSZ != 128
-#  error Polynomial in rand_add is out of date.  Fix it.
-#endif
-
-  RAND_RESOLVE(r);
-
-  i = r->i; rot = r->irot;
-
-  while (sz) {
-    octet o = *c++;
-    r->pool[i] ^= (ROL8(o, rot) ^
-		   r->pool[(i + 1) % RAND_POOLSZ] ^
-		   r->pool[(i + 2) % RAND_POOLSZ] ^
-		   r->pool[(i + 7) % RAND_POOLSZ]);
-    rot = (rot + 5) & 7;
-    i++; if (i >= RAND_POOLSZ) i -= RAND_POOLSZ;
-    sz--;
-  }
-
-  r->i = i;
-  r->irot = rot;
-  r->ibits += goodbits;
-  if (r->ibits > RAND_IBITS)
-    r->ibits = RAND_IBITS;
-}
-
-/* --- @rand_goodbits@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *
- * Returns:	Estimate of the number of good bits remaining in the pool.
- */
-
-unsigned rand_goodbits(rand_pool *r)
-{
-  RAND_RESOLVE(r);
-  return (r->ibits + r->obits);
-}
-
-/* --- @rand_gate@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *
- * Returns:	---
- *
- * Use:		Mixes up the entire state of the generator in a nonreversible
- *		way.
- */
-
-void rand_gate(rand_pool *r)
-{
-  octet mac[RMD160_HASHSZ];
-
-  RAND_RESOLVE(r);
-  TIMER(r);
-
-  /* --- Hash up all the data in the pool --- */
-
-  {
-    rmd160_macctx mc;
-
-    rmd160_macinit(&mc, &r->k);
-    rmd160_machash(&mc, r->pool, sizeof(r->pool));
-    rmd160_machash(&mc, r->buf, sizeof(r->buf));
-    rmd160_macdone(&mc, mac);
-    BURN(mc);
-  }
-
-  /* --- Now mangle all of the data based on the hash --- */
-
-  {
-    blowfish_cbcctx bc;
-
-    blowfish_cbcinit(&bc, mac, sizeof(mac), 0);
-    blowfish_cbcencrypt(&bc, r->pool, r->pool, sizeof(r->pool));
-    blowfish_cbcencrypt(&bc, r->buf, r->buf, sizeof(r->buf));
-    BURN(bc);
-  }
-
-  /* --- Reset the various state variables --- */
-
-  r->o = RAND_SECSZ;
-  r->obits += r->ibits;
-  if (r->obits > RAND_OBITS) {
-    r->ibits = r->obits - r->ibits;
-    r->obits = RAND_OBITS;
-  } else
-    r->ibits = 0;
-  TIMER(r);
-}
-
-/* --- @rand_stretch@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *
- * Returns:	---
- *
- * Use:		Stretches the contents of the output buffer by transforming
- *		it in a nonreversible way.  This doesn't add any entropy
- *		worth speaking about, but it works well enough when the
- *		caller doesn't care about that sort of thing.
- */
-
-void rand_stretch(rand_pool *r)
-{
-  octet mac[RMD160_HASHSZ];
-
-  RAND_RESOLVE(r);
-  TIMER(r);
-
-  /* --- Hash up all the data in the buffer --- */
-
-  {
-    rmd160_macctx mc;
-
-    rmd160_macinit(&mc, &r->k);
-    rmd160_machash(&mc, r->pool, sizeof(r->pool));
-    rmd160_machash(&mc, r->buf, sizeof(r->buf));
-    rmd160_macdone(&mc, mac);
-    BURN(mc);
-  }
-
-  /* --- Now mangle the buffer based on that hash --- */
-
-  {
-    blowfish_cbcctx bc;
-
-    blowfish_cbcinit(&bc, mac, sizeof(mac), 0);
-    blowfish_cbcencrypt(&bc, r->buf, r->buf, sizeof(r->buf));
-    BURN(bc);
-  }
-
-  /* --- Reset the various state variables --- */
-
-  r->o = RAND_SECSZ;
-  TIMER(r);
-}
-
-/* --- @rand_get@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@void *p@ = pointer to output buffer
- *		@size_t sz@ = size of output buffer
- *
- * Returns:	---
- *
- * Use:		Gets random data from the pool.  The pool's contents can't be
- *		determined from the output of this function; nor can the
- *		output data be determined from a knowledge of the data input
- *		to the pool wihtout also having knowledge of the secret key.
- *		The good bits counter is decremented, although no special
- *		action is taken if it reaches zero.
- */
-
-void rand_get(rand_pool *r, void *p, size_t sz)
-{
-  octet *o = p;
-
-  RAND_RESOLVE(r);
-  TIMER(r);
-
-  if (!sz)
-    return;
-  for (;;) {
-    if (r->o + sz <= RAND_BUFSZ) {
-      memcpy(o, r->buf + r->o, sz);
-      r->o += sz;
-      break;
-    } else {
-      size_t chunk = RAND_BUFSZ - r->o;
-      if (chunk) {
-	memcpy(o, r->buf + r->o, chunk);
-	sz -= chunk;
-	o += chunk;
-      }
-      rand_stretch(r);
-    }
-  }
-
-  if (r->obits > sz * 8)
-    r->obits -= sz * 8;
-  else
-    r->obits = 0;
-}
-
-/* --- @rand_getgood@ --- *
- *
- * Arguments:	@rand_pool *r@ = pointer to a randomness pool
- *		@void *p@ = pointer to output buffer
- *		@size_t sz@ = size of output buffer
- *
- * Returns:	---
- *
- * Use:		Gets random data from the pool, ensuring that there are
- *		enough good bits.  This interface isn't recommended: it makes
- *		the generator slow, and doesn't provide much more security
- *		than @rand_get@, assuming you've previously done a
- *		@rand_seed@.
- */
-
-void rand_getgood(rand_pool *r, void *p, size_t sz)
-{
-  octet *o = p;
-
-  RAND_RESOLVE(r);
-
-  if (!sz)
-    return;
-  if (!r->s || !r->s->getnoise) {
-    rand_get(r, p, sz);
-    return;
-  }
-  TIMER(r);
-
-  while (sz) {
-    size_t chunk = sz;
-
-    if (chunk * 8 > r->obits) {
-      if (chunk * 8 > r->ibits + r->obits)
-	do r->s->getnoise(r); while (r->ibits + r->obits < 256);
-      rand_gate(r);
-      if (chunk * 8 > r->obits)
-	chunk = r->obits / 8;
-    }
-
-    if (chunk + r->o > RAND_BUFSZ)
-      chunk = RAND_BUFSZ - r->o;
-
-    memcpy(o, r->buf + r->o, chunk);
-    r->o += chunk;
-    r->obits -= chunk * 8;
-    o += chunk;
-    sz -= chunk;
-  }
-}
-
-/*----- Generic random number generator interface -------------------------*/
-
-#define GRESOLVE(g, r) do {						\
-  if (r != &rand_global)						\
-    g = (gctx *)r;							\
-  else {								\
-    if (!pool)								\
-      pool = (gctx *)rand_create();					\
-    g = pool;								\
-  }									\
-} while (0)
-
-static void gdestroy(grand *r)
-{
-  gctx *g;
-  GRESOLVE(g, r);
-  if (g != pool) {
-    BURN(*g);
-    S_DESTROY(g);
-  }
-}
-
-static int gmisc(grand *r, unsigned op, ...)
-{
-  gctx *g;
-  va_list ap;
-  int rc = 0;
-  va_start(ap, op);
-
-  GRESOLVE(g, r);
-  switch (op) {
-    case GRAND_CHECK:
-      switch (va_arg(ap, unsigned)) {
-	case GRAND_CHECK:
-	case GRAND_SEEDINT:
-	case GRAND_SEEDUINT32:
-	case GRAND_SEEDBLOCK:
-	case GRAND_SEEDRAND:
-	case RAND_GATE:
-	case RAND_STRETCH:
-	case RAND_KEY:
-	case RAND_NOISESRC:
-	case RAND_SEED:
-	case RAND_TIMER:
-	case RAND_GOODBITS:
-	case RAND_ADD:
-	  rc = 1;
-	  break;
-	default:
-	  rc = 0;
-	  break;
-      }
-      break;
-    case GRAND_SEEDINT: {
-      unsigned u = va_arg(ap, unsigned);
-      rand_add(&g->p, &u, sizeof(u), sizeof(u));
-    } break;
-    case GRAND_SEEDUINT32: {
-      uint32 i = va_arg(ap, uint32);
-      rand_add(&g->p, &i, sizeof(i), 4);
-    } break;
-    case GRAND_SEEDBLOCK: {
-      const void *p = va_arg(ap, const void *);
-      size_t sz = va_arg(ap, size_t);
-      rand_add(&g->p, p, sz, sz);
-    } break;
-    case GRAND_SEEDRAND: {
-      grand *rr = va_arg(ap, grand *);
-      octet buf[16];
-      rr->ops->fill(rr, buf, sizeof(buf));
-      rand_add(&g->p, buf, sizeof(buf), 8);
-    } break;
-    case RAND_GATE:
-      rand_gate(&g->p);
-      break;
-    case RAND_STRETCH:
-      rand_stretch(&g->p);
-      break;
-    case RAND_KEY: {
-      const void *k = va_arg(ap, const void *);
-      size_t sz = va_arg(ap, size_t);
-      rand_key(&g->p, k, sz);
-    } break;
-    case RAND_NOISESRC:
-      rand_noisesrc(&g->p, va_arg(ap, const rand_source *));
-      break;
-    case RAND_SEED:
-      rand_seed(&g->p, va_arg(ap, unsigned));
-      break;
-    case RAND_TIMER:
-      TIMER(&g->p);
-      break;
-    case RAND_GOODBITS:
-      rc = rand_goodbits(&g->p);
-      break;
-    case RAND_ADD: {
-      const void *p = va_arg(ap, const void *);
-      size_t sz = va_arg(ap, size_t);
-      unsigned goodbits = va_arg(ap, unsigned);
-      rand_add(&g->p, p, sz, goodbits);
-    } break;
-    default:
-      GRAND_BADOP;
-      break;
-  }
-
-  va_end(ap);
-  return (rc);
-}
-
-static octet gbyte(grand *r)
-{
-  gctx *g;
-  octet o;
-  GRESOLVE(g, r);
-  rand_getgood(&g->p, &o, 1);
-  return (o);
-}
-
-static uint32 gword(grand *r)
-{
-  gctx *g;
-  octet b[4];
-  GRESOLVE(g, r);
-  rand_getgood(&g->p, &b, sizeof(b));
-  return (LOAD32(b));
-}
-
-static void gfill(grand *r, void *p, size_t sz)
-{
-  gctx *g;
-  GRESOLVE(g, r);
-  rand_get(&g->p, p, sz);
-}
-
-static const grand_ops gops = {
-  "rand",
-  GRAND_CRYPTO, 0,
-  gmisc, gdestroy,
-  gword, gbyte, gword, grand_range, gfill
-};
-
-grand rand_global = { &gops };
-
-/* --- @rand_create@ --- *
- *
- * Arguments:	---
- *
- * Returns:	Pointer to a generic generator.
- *
- * Use:		Constructs a generic generator interface over a Catacomb
- *		entropy pool generator.
- */
-
-grand *rand_create(void)
-{
-  gctx *g = S_CREATE(gctx);
-  g->r.ops = &gops;
-  rand_init(&g->p);
-  return (&g->r);
-}
-
-/*----- That's all, folks -------------------------------------------------*/