-/* crypto/bn/bn_ctx.c */
-/* Written by Ulf Moeller for the OpenSSL project. */
-/* ====================================================================
- * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
+/*
+ * Copyright 2000-2019 The OpenSSL Project Authors. 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.
- * ====================================================================
+ * Licensed under the Apache License 2.0 (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/trace.h>
+#include "internal/cryptlib.h"
+#include "bn_lcl.h"
+
+/*-
+ * TODO list
*
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com).
+ * 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.
*/
-#ifndef BN_CTX_DEBUG
-# undef NDEBUG /* avoid conflicting definitions */
-# define NDEBUG
-#endif
+/* 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 */
+/***********/
-#include <stdio.h>
-#include <assert.h>
-#include "cryptlib.h"
-#include <openssl/bn.h>
+/* 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 *);
+static BIGNUM *BN_POOL_get(BN_POOL *, int);
+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 *);
+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;
+ /* Flags. */
+ int flags;
+};
+
+/* Debugging functionality */
+static void ctxdbg(BIO *channel, const char *text, BN_CTX *ctx)
+{
+ unsigned int bnidx = 0, fpidx = 0;
+ BN_POOL_ITEM *item = ctx->pool.head;
+ BN_STACK *stack = &ctx->stack;
+
+ BIO_printf(channel, "%s\n", text);
+ BIO_printf(channel, " (%16p): ", (void*)ctx);
+ while (bnidx < ctx->used) {
+ BIO_printf(channel, "%03x ",
+ item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax);
+ if (!(bnidx % BN_CTX_POOL_SIZE))
+ item = item->next;
+ }
+ BIO_printf(channel, "\n");
+ bnidx = 0;
+ BIO_printf(channel, " %16s : ", "");
+ while (fpidx < stack->depth) {
+ while (bnidx++ < stack->indexes[fpidx])
+ BIO_printf(channel, " ");
+ BIO_printf(channel, "^^^ ");
+ bnidx++;
+ fpidx++;
+ }
+ BIO_printf(channel, "\n");
+}
+
+#define CTXDBG(str, ctx) \
+ OSSL_TRACE_BEGIN(BN_CTX) { \
+ ctxdbg(trc_out, str, ctx); \
+ } OSSL_TRACE_END(BN_CTX)
BN_CTX *BN_CTX_new(void)
- {
- BN_CTX *ret;
-
- ret=(BN_CTX *)Malloc(sizeof(BN_CTX));
- if (ret == NULL)
- {
- BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
- return(NULL);
- }
-
- BN_CTX_init(ret);
- ret->flags=BN_FLG_MALLOCED;
- return(ret);
- }
-
-void BN_CTX_init(BN_CTX *ctx)
- {
- int i;
- ctx->tos = 0;
- ctx->flags = 0;
- ctx->depth = 0;
- ctx->too_many = 0;
- for (i = 0; i < BN_CTX_NUM; i++)
- BN_init(&(ctx->bn[i]));
- }
+{
+ BN_CTX *ret;
-void BN_CTX_free(BN_CTX *ctx)
- {
- int i;
+ if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
+ BNerr(BN_F_BN_CTX_NEW, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+ /* Initialise the structure */
+ BN_POOL_init(&ret->pool);
+ BN_STACK_init(&ret->stack);
+ return ret;
+}
- if (ctx == NULL) return;
- assert(ctx->depth == 0);
+BN_CTX *BN_CTX_secure_new(void)
+{
+ BN_CTX *ret = BN_CTX_new();
- for (i=0; i < BN_CTX_NUM; i++)
- BN_clear_free(&(ctx->bn[i]));
- if (ctx->flags & BN_FLG_MALLOCED)
- Free(ctx);
- }
+ if (ret != NULL)
+ ret->flags = BN_FLG_SECURE;
+ return ret;
+}
+
+void BN_CTX_free(BN_CTX *ctx)
+{
+ if (ctx == NULL)
+ return;
+ OSSL_TRACE_BEGIN(BN_CTX) {
+ BN_POOL_ITEM *pool = ctx->pool.head;
+ BIO_printf(trc_out,
+ "BN_CTX_free(): stack-size=%d, pool-bignums=%d\n",
+ ctx->stack.size, ctx->pool.size);
+ BIO_printf(trc_out, " dmaxs: ");
+ while (pool) {
+ unsigned loop = 0;
+ while (loop < BN_CTX_POOL_SIZE)
+ BIO_printf(trc_out, "%02x ", pool->vals[loop++].dmax);
+ pool = pool->next;
+ }
+ BIO_printf(trc_out, "\n");
+ } OSSL_TRACE_END(BN_CTX);
+ BN_STACK_finish(&ctx->stack);
+ BN_POOL_finish(&ctx->pool);
+ OPENSSL_free(ctx);
+}
void BN_CTX_start(BN_CTX *ctx)
- {
- if (ctx->depth < BN_CTX_NUM_POS)
- ctx->pos[ctx->depth] = ctx->tos;
- ctx->depth++;
- }
+{
+ CTXDBG("ENTER 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)) {
+ BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);
+ ctx->err_stack++;
+ }
+ CTXDBG("LEAVE BN_CTX_start()", ctx);
+}
+
+void BN_CTX_end(BN_CTX *ctx)
+{
+ if (ctx == NULL)
+ return;
+ CTXDBG("ENTER 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("LEAVE BN_CTX_end()", ctx);
+}
BIGNUM *BN_CTX_get(BN_CTX *ctx)
- {
- if (ctx->depth > BN_CTX_NUM_POS || ctx->tos >= BN_CTX_NUM)
- {
- if (!ctx->too_many)
- {
- BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
- /* disable error code until SSL_CTX_end is called: */
- ctx->too_many = 1;
- }
- return NULL;
- }
- return (&(ctx->bn[ctx->tos++]));
- }
+{
+ BIGNUM *ret;
-void BN_CTX_end(BN_CTX *ctx)
- {
- if (ctx == NULL) return;
- assert(ctx->depth > 0);
- if (ctx->depth == 0)
- /* should never happen, but we can tolerate it if not in
- * debug mode (could be a 'goto err' in the calling function
- * before BN_CTX_start was reached) */
- BN_CTX_start(ctx);
-
- ctx->too_many = 0;
- ctx->depth--;
- if (ctx->depth < BN_CTX_NUM_POS)
- ctx->tos = ctx->pos[ctx->depth];
- }
+ CTXDBG("ENTER BN_CTX_get()", ctx);
+ if (ctx->err_stack || ctx->too_many)
+ return NULL;
+ if ((ret = BN_POOL_get(&ctx->pool, ctx->flags)) == NULL) {
+ /*
+ * Setting too_many prevents repeated "get" attempts from cluttering
+ * the error stack.
+ */
+ ctx->too_many = 1;
+ BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);
+ return NULL;
+ }
+ /* OK, make sure the returned bignum is "zero" */
+ BN_zero(ret);
+ /* clear BN_FLG_CONSTTIME if leaked from previous frames */
+ ret->flags &= (~BN_FLG_CONSTTIME);
+ ctx->used++;
+ CTXDBG("LEAVE BN_CTX_get()", ctx);
+ 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)
+{
+ OPENSSL_free(st->indexes);
+ st->indexes = NULL;
+}
+
+
+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;
+
+ if ((newitems = OPENSSL_malloc(sizeof(*newitems) * newsize)) == NULL) {
+ BNerr(BN_F_BN_STACK_PUSH, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+ if (st->depth)
+ memcpy(newitems, st->indexes, sizeof(*newitems) * st->depth);
+ OPENSSL_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)
+{
+ unsigned int loop;
+ BIGNUM *bn;
+
+ while (p->head) {
+ for (loop = 0, bn = p->head->vals; loop++ < BN_CTX_POOL_SIZE; bn++)
+ if (bn->d)
+ BN_clear_free(bn);
+ p->current = p->head->next;
+ OPENSSL_free(p->head);
+ p->head = p->current;
+ }
+}
+
+
+static BIGNUM *BN_POOL_get(BN_POOL *p, int flag)
+{
+ BIGNUM *bn;
+ unsigned int loop;
+
+ /* Full; allocate a new pool item and link it in. */
+ if (p->used == p->size) {
+ BN_POOL_ITEM *item;
+
+ if ((item = OPENSSL_malloc(sizeof(*item))) == NULL) {
+ BNerr(BN_F_BN_POOL_GET, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+ for (loop = 0, bn = item->vals; loop++ < BN_CTX_POOL_SIZE; bn++) {
+ bn_init(bn);
+ if ((flag & BN_FLG_SECURE) != 0)
+ BN_set_flags(bn, BN_FLG_SECURE);
+ }
+ item->prev = p->tail;
+ item->next = NULL;
+
+ if (p->head == NULL)
+ 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 == 0) {
+ offset = BN_CTX_POOL_SIZE - 1;
+ p->current = p->current->prev;
+ } else
+ offset--;
+ }
+}
projects / openssl.git / blobdiff