/src/libressl/crypto/bn/bn_ctx.c

Source (jump to first uncovered line)
/* $OpenBSD: bn_ctx.c,v 1.16 2019/08/20 10:59:09 schwarze Exp $ */
/* Written by Ulf Moeller for the OpenSSL project. */
/* ====================================================================
 * Copyright (c) 1998-2004 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#if !defined(BN_CTX_DEBUG) && !defined(BN_DEBUG)
#ifndef NDEBUG
#define NDEBUG
#endif
#endif

#include <stdio.h>
#include <string.h>

#include <openssl/opensslconf.h>

#include <openssl/err.h>

#include "bn_lcl.h"

/* TODO list
 *
 * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and
 * check they can be safely removed.
 *  - Check +1 and other ugliness in BN_from_montgomery()
 *
 * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an
 * appropriate 'block' size that will be honoured by bn_expand_internal() to
 * prevent piddly little reallocations. OTOH, profiling bignum expansions in
 * BN_CTX doesn't show this to be a big issue.
 */

/* How many bignums are in each "pool item"; */
#define BN_CTX_POOL_SIZE  16
/* The stack frame info is resizing, set a first-time expansion size; */
#define BN_CTX_START_FRAMES 32

/***********/
/* BN_POOL */
/***********/

/* A bundle of bignums that can be linked with other bundles */
typedef struct bignum_pool_item {
  /* The bignum values */
  BIGNUM vals[BN_CTX_POOL_SIZE];
  /* Linked-list admin */
  struct bignum_pool_item *prev, *next;
} BN_POOL_ITEM;

/* A linked-list of bignums grouped in bundles */
typedef struct bignum_pool {
  /* Linked-list admin */
  BN_POOL_ITEM *head, *current, *tail;
  /* Stack depth and allocation size */
  unsigned used, size;
} BN_POOL;

static void   BN_POOL_init(BN_POOL *);
static void   BN_POOL_finish(BN_POOL *);
#ifndef OPENSSL_NO_DEPRECATED
static void   BN_POOL_reset(BN_POOL *);
#endif
static BIGNUM *   BN_POOL_get(BN_POOL *);
static void   BN_POOL_release(BN_POOL *, unsigned int);

/************/
/* BN_STACK */
/************/

/* A wrapper to manage the "stack frames" */
typedef struct bignum_ctx_stack {
  /* Array of indexes into the bignum stack */
  unsigned int *indexes;
  /* Number of stack frames, and the size of the allocated array */
  unsigned int depth, size;
} BN_STACK;

static void   BN_STACK_init(BN_STACK *);
static void   BN_STACK_finish(BN_STACK *);
#ifndef OPENSSL_NO_DEPRECATED
static void   BN_STACK_reset(BN_STACK *);
#endif
static int    BN_STACK_push(BN_STACK *, unsigned int);
static unsigned int BN_STACK_pop(BN_STACK *);

/**********/
/* BN_CTX */
/**********/

/* The opaque BN_CTX type */
struct bignum_ctx {
  /* The bignum bundles */
  BN_POOL pool;
  /* The "stack frames", if you will */
  BN_STACK stack;
  /* The number of bignums currently assigned */
  unsigned int used;
  /* Depth of stack overflow */
  int err_stack;
  /* Block "gets" until an "end" (compatibility behaviour) */
  int too_many;
};

/* Enable this to find BN_CTX bugs */
#ifdef BN_CTX_DEBUG
static const char *ctxdbg_cur = NULL;

static void
ctxdbg(BN_CTX *ctx)
{
  unsigned int bnidx = 0, fpidx = 0;
  BN_POOL_ITEM *item = ctx->pool.head;
  BN_STACK *stack = &ctx->stack;

  fprintf(stderr, "(%08x): ", (unsigned int)ctx);
  while (bnidx < ctx->used) {
    fprintf(stderr, "%03x ",
        item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax);
    if (!(bnidx % BN_CTX_POOL_SIZE))
      item = item->next;
  }
  fprintf(stderr, "\n");
  bnidx = 0;
  fprintf(stderr, "          : ");
  while (fpidx < stack->depth) {
    while (bnidx++ < stack->indexes[fpidx])
      fprintf(stderr, "    ");
    fprintf(stderr, "^^^ ");
    bnidx++;
    fpidx++;
  }
  fprintf(stderr, "\n");
}
#define CTXDBG_ENTRY(str, ctx) \
  do { \
    ctxdbg_cur = (str); \
    fprintf(stderr, "Starting %s\n", ctxdbg_cur); \
    ctxdbg(ctx); \
  } while(0)

#define CTXDBG_EXIT(ctx) \
  do { \
    fprintf(stderr, "Ending %s\n", ctxdbg_cur); \
    ctxdbg(ctx); \
  } while(0)

#define CTXDBG_RET(ctx,ret)
#else
#define CTXDBG_ENTRY(str, ctx)
#define CTXDBG_EXIT(ctx)
#define CTXDBG_RET(ctx,ret)
#endif

/* This function is an evil legacy and should not be used. This implementation
 * is WYSIWYG, though I've done my best. */
#ifndef OPENSSL_NO_DEPRECATED
void
BN_CTX_init(BN_CTX *ctx)
{
  /* Assume the caller obtained the context via BN_CTX_new() and so is
   * trying to reset it for use. Nothing else makes sense, least of all
   * binary compatibility from a time when they could declare a static
   * variable. */
  BN_POOL_reset(&ctx->pool);
  BN_STACK_reset(&ctx->stack);
  ctx->used = 0;
  ctx->err_stack = 0;
  ctx->too_many = 0;
}
#endif

BN_CTX *
BN_CTX_new(void)
{
  BN_CTX *ret = malloc(sizeof(BN_CTX));
  if (!ret) {
    BNerror(ERR_R_MALLOC_FAILURE);
    return NULL;
  }

  /* Initialise the structure */
  BN_POOL_init(&ret->pool);
  BN_STACK_init(&ret->stack);
  ret->used = 0;
  ret->err_stack = 0;
  ret->too_many = 0;
  return ret;
}

void
BN_CTX_free(BN_CTX *ctx)
{
  if (ctx == NULL)
    return;
#ifdef BN_CTX_DEBUG
  {
    BN_POOL_ITEM *pool = ctx->pool.head;
    fprintf(stderr, "BN_CTX_free, stack-size=%d, pool-bignums=%d\n",
        ctx->stack.size, ctx->pool.size);
    fprintf(stderr, "dmaxs: ");
    while (pool) {
      unsigned loop = 0;
      while (loop < BN_CTX_POOL_SIZE)
        fprintf(stderr, "%02x ",
            pool->vals[loop++].dmax);
      pool = pool->next;
    }
    fprintf(stderr, "\n");
  }
#endif
  BN_STACK_finish(&ctx->stack);
  BN_POOL_finish(&ctx->pool);
  free(ctx);
}

void
BN_CTX_start(BN_CTX *ctx)
{
  CTXDBG_ENTRY("BN_CTX_start", ctx);

  /* If we're already overflowing ... */
  if (ctx->err_stack || ctx->too_many)
    ctx->err_stack++;
  /* (Try to) get a new frame pointer */
  else if (!BN_STACK_push(&ctx->stack, ctx->used)) {
    BNerror(BN_R_TOO_MANY_TEMPORARY_VARIABLES);
    ctx->err_stack++;
  }
  CTXDBG_EXIT(ctx);
}

void
BN_CTX_end(BN_CTX *ctx)
{
  if (ctx == NULL)
    return;

  CTXDBG_ENTRY("BN_CTX_end", ctx);

  if (ctx->err_stack)
    ctx->err_stack--;
  else {
    unsigned int fp = BN_STACK_pop(&ctx->stack);
    /* Does this stack frame have anything to release? */
    if (fp < ctx->used)
      BN_POOL_release(&ctx->pool, ctx->used - fp);
    ctx->used = fp;
    /* Unjam "too_many" in case "get" had failed */
    ctx->too_many = 0;
  }
  CTXDBG_EXIT(ctx);
}

BIGNUM *
BN_CTX_get(BN_CTX *ctx)
{
  BIGNUM *ret;

  CTXDBG_ENTRY("BN_CTX_get", ctx);

  if (ctx->err_stack || ctx->too_many)
    return NULL;
  if ((ret = BN_POOL_get(&ctx->pool)) == NULL) {
    /* Setting too_many prevents repeated "get" attempts from
     * cluttering the error stack. */
    ctx->too_many = 1;
    BNerror(BN_R_TOO_MANY_TEMPORARY_VARIABLES);
    return NULL;
  }
  /* OK, make sure the returned bignum is "zero" */
  BN_zero(ret);
  ctx->used++;
  CTXDBG_RET(ctx, ret);
  return ret;
}

/************/
/* BN_STACK */
/************/

static void
BN_STACK_init(BN_STACK *st)
{
  st->indexes = NULL;
  st->depth = st->size = 0;
}

static void
BN_STACK_finish(BN_STACK *st)
{
  if (st->size)
    free(st->indexes);
}

#ifndef OPENSSL_NO_DEPRECATED
static void
BN_STACK_reset(BN_STACK *st)
{
  st->depth = 0;
}
#endif

static int
BN_STACK_push(BN_STACK *st, unsigned int idx)
{
  if (st->depth == st->size)
    /* Need to expand */
  {
    unsigned int newsize = (st->size ?
        (st->size * 3 / 2) : BN_CTX_START_FRAMES);
    unsigned int *newitems = reallocarray(NULL,
        newsize, sizeof(unsigned int));
    if (!newitems)
      return 0;
    if (st->depth)
      memcpy(newitems, st->indexes, st->depth *
          sizeof(unsigned int));
    if (st->size)
      free(st->indexes);
    st->indexes = newitems;
    st->size = newsize;
  }
  st->indexes[(st->depth)++] = idx;
  return 1;
}

static unsigned int
BN_STACK_pop(BN_STACK *st)
{
  return st->indexes[--(st->depth)];
}

/***********/
/* BN_POOL */
/***********/

static void
BN_POOL_init(BN_POOL *p)
{
  p->head = p->current = p->tail = NULL;
  p->used = p->size = 0;
}

static void
BN_POOL_finish(BN_POOL *p)
{
  while (p->head) {
    unsigned int loop = 0;
    BIGNUM *bn = p->head->vals;
    while (loop++ < BN_CTX_POOL_SIZE) {
      if (bn->d)
        BN_clear_free(bn);
      bn++;
    }
    p->current = p->head->next;
    free(p->head);
    p->head = p->current;
  }
}

#ifndef OPENSSL_NO_DEPRECATED
static void
BN_POOL_reset(BN_POOL *p)
{
  BN_POOL_ITEM *item = p->head;
  while (item) {
    unsigned int loop = 0;
    BIGNUM *bn = item->vals;
    while (loop++ < BN_CTX_POOL_SIZE) {
      if (bn->d)
        BN_clear(bn);
      bn++;
    }
    item = item->next;
  }
  p->current = p->head;
  p->used = 0;
}
#endif

static BIGNUM *
BN_POOL_get(BN_POOL *p)
{
  if (p->used == p->size) {
    BIGNUM *bn;
    unsigned int loop = 0;
    BN_POOL_ITEM *item = malloc(sizeof(BN_POOL_ITEM));
    if (!item)
      return NULL;
    /* Initialise the structure */
    bn = item->vals;
    while (loop++ < BN_CTX_POOL_SIZE)
      BN_init(bn++);
    item->prev = p->tail;
    item->next = NULL;
    /* Link it in */
    if (!p->head)
      p->head = p->current = p->tail = item;
    else {
      p->tail->next = item;
      p->tail = item;
      p->current = item;
    }
    p->size += BN_CTX_POOL_SIZE;
    p->used++;
    /* Return the first bignum from the new pool */
    return item->vals;
  }
  if (!p->used)
    p->current = p->head;
  else if ((p->used % BN_CTX_POOL_SIZE) == 0)
    p->current = p->current->next;
  return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE);
}

static void
BN_POOL_release(BN_POOL *p, unsigned int num)
{
  unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;

  p->used -= num;
  while (num--) {
    bn_check_top(p->current->vals + offset);
    if (!offset) {
      offset = BN_CTX_POOL_SIZE - 1;
      p->current = p->current->prev;
    } else
      offset--;
  }
}

Coverage Report

Created: 2022-08-24 06:31

Line	Count	Source (jump to first uncovered line)
1		/* $OpenBSD: bn_ctx.c,v 1.16 2019/08/20 10:59:09 schwarze Exp $ */
2		/* Written by Ulf Moeller for the OpenSSL project. */
3		/* ====================================================================
4		* Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved.
5		*
6		* Redistribution and use in source and binary forms, with or without
7		* modification, are permitted provided that the following conditions
8		* are met:
9		*
10		* 1. Redistributions of source code must retain the above copyright
11		* notice, this list of conditions and the following disclaimer.
12		*
13		* 2. Redistributions in binary form must reproduce the above copyright
14		* notice, this list of conditions and the following disclaimer in
15		* the documentation and/or other materials provided with the
16		* distribution.
17		*
18		* 3. All advertising materials mentioning features or use of this
19		* software must display the following acknowledgment:
20		* "This product includes software developed by the OpenSSL Project
21		* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
22		*
23		* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
24		* endorse or promote products derived from this software without
25		* prior written permission. For written permission, please contact
26		* openssl-core@openssl.org.
27		*
28		* 5. Products derived from this software may not be called "OpenSSL"
29		* nor may "OpenSSL" appear in their names without prior written
30		* permission of the OpenSSL Project.
31		*
32		* 6. Redistributions of any form whatsoever must retain the following
33		* acknowledgment:
34		* "This product includes software developed by the OpenSSL Project
35		* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
36		*
37		* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
38		* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39		* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
40		* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
41		* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42		* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
43		* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
44		* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
45		* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
46		* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
47		* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
48		* OF THE POSSIBILITY OF SUCH DAMAGE.
49		* ====================================================================
50		*
51		* This product includes cryptographic software written by Eric Young
52		* (eay@cryptsoft.com). This product includes software written by Tim
53		* Hudson (tjh@cryptsoft.com).
54		*
55		*/
56
57		#if !defined(BN_CTX_DEBUG) && !defined(BN_DEBUG)
58		#ifndef NDEBUG
59		#define NDEBUG
60		#endif
61		#endif
62
63		#include <stdio.h>
64		#include <string.h>
65
66		#include <openssl/opensslconf.h>
67
68		#include <openssl/err.h>
69
70		#include "bn_lcl.h"
71
72		/* TODO list
73		*
74		* 1. Check a bunch of "(words+1)" type hacks in various bignum functions and
75		* check they can be safely removed.
76		* - Check +1 and other ugliness in BN_from_montgomery()
77		*
78		* 2. Consider allowing a BN_new_ex() that, at least, lets you specify an
79		* appropriate 'block' size that will be honoured by bn_expand_internal() to
80		* prevent piddly little reallocations. OTOH, profiling bignum expansions in
81		* BN_CTX doesn't show this to be a big issue.
82		*/
83
84		/* How many bignums are in each "pool item"; */
85	294M	#define BN_CTX_POOL_SIZE 16
86		/* The stack frame info is resizing, set a first-time expansion size; */
87	112k	#define BN_CTX_START_FRAMES 32
88
89		/***********/
90		/* BN_POOL */
91		/***********/
92
93		/* A bundle of bignums that can be linked with other bundles */
94		typedef struct bignum_pool_item {
95		/* The bignum values */
96		BIGNUM vals[BN_CTX_POOL_SIZE];
97		/* Linked-list admin */
98		struct bignum_pool_item prev, next;
99		} BN_POOL_ITEM;
100
101		/* A linked-list of bignums grouped in bundles */
102		typedef struct bignum_pool {
103		/* Linked-list admin */
104		BN_POOL_ITEM head, current, *tail;
105		/* Stack depth and allocation size */
106		unsigned used, size;
107		} BN_POOL;
108
109		static void BN_POOL_init(BN_POOL *);
110		static void BN_POOL_finish(BN_POOL *);
111		#ifndef OPENSSL_NO_DEPRECATED
112		static void BN_POOL_reset(BN_POOL *);
113		#endif
114		static BIGNUM * BN_POOL_get(BN_POOL *);
115		static void BN_POOL_release(BN_POOL *, unsigned int);
116
117		/************/
118		/* BN_STACK */
119		/************/
120
121		/* A wrapper to manage the "stack frames" */
122		typedef struct bignum_ctx_stack {
123		/* Array of indexes into the bignum stack */
124		unsigned int *indexes;
125		/* Number of stack frames, and the size of the allocated array */
126		unsigned int depth, size;
127		} BN_STACK;
128
129		static void BN_STACK_init(BN_STACK *);
130		static void BN_STACK_finish(BN_STACK *);
131		#ifndef OPENSSL_NO_DEPRECATED
132		static void BN_STACK_reset(BN_STACK *);
133		#endif
134		static int BN_STACK_push(BN_STACK *, unsigned int);
135		static unsigned int BN_STACK_pop(BN_STACK *);
136
137		/**********/
138		/* BN_CTX */
139		/**********/
140
141		/* The opaque BN_CTX type */
142		struct bignum_ctx {
143		/* The bignum bundles */
144		BN_POOL pool;
145		/* The "stack frames", if you will */
146		BN_STACK stack;
147		/* The number of bignums currently assigned */
148		unsigned int used;
149		/* Depth of stack overflow */
150		int err_stack;
151		/* Block "gets" until an "end" (compatibility behaviour) */
152		int too_many;
153		};
154
155		/* Enable this to find BN_CTX bugs */
156		#ifdef BN_CTX_DEBUG
157		static const char *ctxdbg_cur = NULL;
158
159		static void
160		ctxdbg(BN_CTX *ctx)
161		{
162		unsigned int bnidx = 0, fpidx = 0;
163		BN_POOL_ITEM *item = ctx->pool.head;
164		BN_STACK *stack = &ctx->stack;
165
166		fprintf(stderr, "(%08x): ", (unsigned int)ctx);
167		while (bnidx < ctx->used) {
168		fprintf(stderr, "%03x ",
169		item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax);
170		if (!(bnidx % BN_CTX_POOL_SIZE))
171		item = item->next;
172		}
173		fprintf(stderr, "\n");
174		bnidx = 0;
175		fprintf(stderr, " : ");
176		while (fpidx < stack->depth) {
177		while (bnidx++ < stack->indexes[fpidx])
178		fprintf(stderr, " ");
179		fprintf(stderr, "^^^ ");
180		bnidx++;
181		fpidx++;
182		}
183		fprintf(stderr, "\n");
184		}
185		#define CTXDBG_ENTRY(str, ctx) \
186		do { \
187		ctxdbg_cur = (str); \
188		fprintf(stderr, "Starting %s\n", ctxdbg_cur); \
189		ctxdbg(ctx); \
190		} while(0)
191
192		#define CTXDBG_EXIT(ctx) \
193		do { \
194		fprintf(stderr, "Ending %s\n", ctxdbg_cur); \
195		ctxdbg(ctx); \
196		} while(0)
197
198		#define CTXDBG_RET(ctx,ret)
199		#else
200		#define CTXDBG_ENTRY(str, ctx)
201		#define CTXDBG_EXIT(ctx)
202		#define CTXDBG_RET(ctx,ret)
203		#endif
204
205		/* This function is an evil legacy and should not be used. This implementation
206		* is WYSIWYG, though I've done my best. */
207		#ifndef OPENSSL_NO_DEPRECATED
208		void
209		BN_CTX_init(BN_CTX *ctx)
210	0	{
211		/* Assume the caller obtained the context via BN_CTX_new() and so is
212		* trying to reset it for use. Nothing else makes sense, least of all
213		* binary compatibility from a time when they could declare a static
214		* variable. */
215	0	BN_POOL_reset(&ctx->pool);
216	0	BN_STACK_reset(&ctx->stack);
217	0	ctx->used = 0;
218	0	ctx->err_stack = 0;
219	0	ctx->too_many = 0;
220	0	}
221		#endif
222
223		BN_CTX *
224		BN_CTX_new(void)
225	121k	{
226	121k	BN_CTX *ret = malloc(sizeof(BN_CTX));
227	121k	if (!ret) {
228	0	BNerror(ERR_R_MALLOC_FAILURE);
229	0	return NULL;
230	0	}
231
232		/* Initialise the structure */
233	121k	BN_POOL_init(&ret->pool);
234	121k	BN_STACK_init(&ret->stack);
235	121k	ret->used = 0;
236	121k	ret->err_stack = 0;
237	121k	ret->too_many = 0;
238	121k	return ret;
239	121k	}
240
241		void
242		BN_CTX_free(BN_CTX *ctx)
243	12.9M	{
244	12.9M	if (ctx == NULL)
245	12.8M	return;
246		#ifdef BN_CTX_DEBUG
247		{
248		BN_POOL_ITEM *pool = ctx->pool.head;
249		fprintf(stderr, "BN_CTX_free, stack-size=%d, pool-bignums=%d\n",
250		ctx->stack.size, ctx->pool.size);
251		fprintf(stderr, "dmaxs: ");
252		while (pool) {
253		unsigned loop = 0;
254		while (loop < BN_CTX_POOL_SIZE)
255		fprintf(stderr, "%02x ",
256		pool->vals[loop++].dmax);
257		pool = pool->next;
258		}
259		fprintf(stderr, "\n");
260		}
261		#endif
262	121k	BN_STACK_finish(&ctx->stack);
263	121k	BN_POOL_finish(&ctx->pool);
264	121k	free(ctx);
265	121k	}
266
267		void
268		BN_CTX_start(BN_CTX *ctx)
269	45.4M	{
270	45.4M	CTXDBG_ENTRY("BN_CTX_start", ctx);
271
272		/* If we're already overflowing ... */
273	45.4M	if (ctx->err_stack \|\| ctx->too_many)
274	0	ctx->err_stack++;
275		/* (Try to) get a new frame pointer */
276	45.4M	else if (!BN_STACK_push(&ctx->stack, ctx->used)) {
277	0	BNerror(BN_R_TOO_MANY_TEMPORARY_VARIABLES);
278	0	ctx->err_stack++;
279	0	}
280	45.4M	CTXDBG_EXIT(ctx);
281	45.4M	}
282
283		void
284		BN_CTX_end(BN_CTX *ctx)
285	45.4M	{
286	45.4M	if (ctx == NULL)
287	0	return;
288
289	45.4M	CTXDBG_ENTRY("BN_CTX_end", ctx);
290
291	45.4M	if (ctx->err_stack)
292	0	ctx->err_stack--;
293	45.4M	else {
294	45.4M	unsigned int fp = BN_STACK_pop(&ctx->stack);
295		/* Does this stack frame have anything to release? */
296	45.4M	if (fp < ctx->used)
297	36.6M	BN_POOL_release(&ctx->pool, ctx->used - fp);
298	45.4M	ctx->used = fp;
299		/* Unjam "too_many" in case "get" had failed */
300	45.4M	ctx->too_many = 0;
301	45.4M	}
302	45.4M	CTXDBG_EXIT(ctx);
303	45.4M	}
304
305		BIGNUM *
306		BN_CTX_get(BN_CTX *ctx)
307	126M	{
308	126M	BIGNUM *ret;
309
310	126M	CTXDBG_ENTRY("BN_CTX_get", ctx);
311
312	126M	if (ctx->err_stack \|\| ctx->too_many)
313	0	return NULL;
314	126M	if ((ret = BN_POOL_get(&ctx->pool)) == NULL) {
315		/* Setting too_many prevents repeated "get" attempts from
316		* cluttering the error stack. */
317	0	ctx->too_many = 1;
318	0	BNerror(BN_R_TOO_MANY_TEMPORARY_VARIABLES);
319	0	return NULL;
320	0	}
321		/* OK, make sure the returned bignum is "zero" */
322	126M	BN_zero(ret);
323	126M	ctx->used++;
324	126M	CTXDBG_RET(ctx, ret);
325	126M	return ret;
326	126M	}
327
328		/************/
329		/* BN_STACK */
330		/************/
331
332		static void
333		BN_STACK_init(BN_STACK *st)
334	121k	{
335	121k	st->indexes = NULL;
336	121k	st->depth = st->size = 0;
337	121k	}
338
339		static void
340		BN_STACK_finish(BN_STACK *st)
341	121k	{
342	121k	if (st->size)
343	112k	free(st->indexes);
344	121k	}
345
346		#ifndef OPENSSL_NO_DEPRECATED
347		static void
348		BN_STACK_reset(BN_STACK *st)
349	0	{
350	0	st->depth = 0;
351	0	}
352		#endif
353
354		static int
355		BN_STACK_push(BN_STACK *st, unsigned int idx)
356	45.4M	{
357	45.4M	if (st->depth == st->size)
358		/* Need to expand */
359	112k	{
360	112k	unsigned int newsize = (st->size ?
361	112k	(st->size * 3 / 2) : BN_CTX_START_FRAMES);
362	112k	unsigned int *newitems = reallocarray(NULL,
363	112k	newsize, sizeof(unsigned int));
364	112k	if (!newitems)
365	0	return 0;
366	112k	if (st->depth)
367	0	memcpy(newitems, st->indexes, st->depth *
368	0	sizeof(unsigned int));
369	112k	if (st->size)
370	0	free(st->indexes);
371	112k	st->indexes = newitems;
372	112k	st->size = newsize;
373	112k	}
374	45.4M	st->indexes[(st->depth)++] = idx;
375	45.4M	return 1;
376	45.4M	}
377
378		static unsigned int
379		BN_STACK_pop(BN_STACK *st)
380	45.4M	{
381	45.4M	return st->indexes[--(st->depth)];
382	45.4M	}
383
384		/***********/
385		/* BN_POOL */
386		/***********/
387
388		static void
389		BN_POOL_init(BN_POOL *p)
390	121k	{
391	121k	p->head = p->current = p->tail = NULL;
392	121k	p->used = p->size = 0;
393	121k	}
394
395		static void
396		BN_POOL_finish(BN_POOL *p)
397	121k	{
398	249k	while (p->head) {
399	127k	unsigned int loop = 0;
400	127k	BIGNUM *bn = p->head->vals;
401	2.16M	while (loop++ < BN_CTX_POOL_SIZE) {
402	2.04M	if (bn->d)
403	1.31M	BN_clear_free(bn);
404	2.04M	bn++;
405	2.04M	}
406	127k	p->current = p->head->next;
407	127k	free(p->head);
408	127k	p->head = p->current;
409	127k	}
410	121k	}
411
412		#ifndef OPENSSL_NO_DEPRECATED
413		static void
414		BN_POOL_reset(BN_POOL *p)
415	0	{
416	0	BN_POOL_ITEM *item = p->head;
417	0	while (item) {
418	0	unsigned int loop = 0;
419	0	BIGNUM *bn = item->vals;
420	0	while (loop++ < BN_CTX_POOL_SIZE) {
421	0	if (bn->d)
422	0	BN_clear(bn);
423	0	bn++;
424	0	}
425	0	item = item->next;
426	0	}
427	0	p->current = p->head;
428	0	p->used = 0;
429	0	}
430		#endif
431
432		static BIGNUM *
433		BN_POOL_get(BN_POOL *p)
434	126M	{
435	126M	if (p->used == p->size) {
436	127k	BIGNUM *bn;
437	127k	unsigned int loop = 0;
438	127k	BN_POOL_ITEM *item = malloc(sizeof(BN_POOL_ITEM));
439	127k	if (!item)
440	0	return NULL;
441		/* Initialise the structure */
442	127k	bn = item->vals;
443	2.16M	while (loop++ < BN_CTX_POOL_SIZE)
444	2.04M	BN_init(bn++);
445	127k	item->prev = p->tail;
446	127k	item->next = NULL;
447		/* Link it in */
448	127k	if (!p->head)
449	112k	p->head = p->current = p->tail = item;
450	14.7k	else {
451	14.7k	p->tail->next = item;
452	14.7k	p->tail = item;
453	14.7k	p->current = item;
454	14.7k	}
455	127k	p->size += BN_CTX_POOL_SIZE;
456	127k	p->used++;
457		/* Return the first bignum from the new pool */
458	127k	return item->vals;
459	127k	}
460	126M	if (!p->used)
461	1.32M	p->current = p->head;
462	125M	else if ((p->used % BN_CTX_POOL_SIZE) == 0)
463	537k	p->current = p->current->next;
464	126M	return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE);
465	126M	}
466
467		static void
468		BN_POOL_release(BN_POOL *p, unsigned int num)
469	36.6M	{
470	36.6M	unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
471
472	36.6M	p->used -= num;
473	163M	while (num--) {
474	126M	bn_check_top(p->current->vals + offset);
475	126M	if (!offset) {
476	1.99M	offset = BN_CTX_POOL_SIZE - 1;
477	1.99M	p->current = p->current->prev;
478	1.99M	} else
479	124M	offset--;
480	126M	}
481	36.6M	}