99ba9fd02f
In the BN_hex2bn function the number of hex digits is calculated using an int value |i|. Later |bn_expand| is called with a value of |i * 4|. For large values of |i| this can result in |bn_expand| not allocating any memory because |i * 4| is negative. This leaves ret->d as NULL leading to a subsequent NULL ptr deref. For very large values of |i|, the calculation |i * 4| could be a positive value smaller than |i|. In this case memory is allocated to ret->d, but it is insufficiently sized leading to heap corruption. A similar issue exists in BN_dec2bn. This could have security consequences if BN_hex2bn/BN_dec2bn is ever called by user applications with very large untrusted hex/dec data. This is anticipated to be a rare occurrence. All OpenSSL internal usage of this function uses data that is not expected to be untrusted, e.g. config file data or application command line arguments. If user developed applications generate config file data based on untrusted data then it is possible that this could also lead to security consequences. This is also anticipated to be a rare. Issue reported by Guido Vranken. CVE-2016-0797 Reviewed-by: Andy Polyakov <appro@openssl.org>
127 lines
4.5 KiB
C
127 lines
4.5 KiB
C
/* ====================================================================
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* Copyright (c) 1998-2014 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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#ifndef HEADER_BN_INT_H
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# define HEADER_BN_INT_H
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# include <openssl/bn.h>
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# include <limits.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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BIGNUM *bn_wexpand(BIGNUM *a, int words);
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BIGNUM *bn_expand2(BIGNUM *a, int words);
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void bn_correct_top(BIGNUM *a);
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/*
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* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
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* This is an array r[] of values that are either zero or odd with an
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* absolute value less than 2^w satisfying scalar = \sum_j r[j]*2^j where at
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* most one of any w+1 consecutive digits is non-zero with the exception that
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* the most significant digit may be only w-1 zeros away from that next
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* non-zero digit.
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*/
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signed char *bn_compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len);
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int bn_get_top(const BIGNUM *a);
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void bn_set_top(BIGNUM *a, int top);
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int bn_get_dmax(const BIGNUM *a);
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/* Set all words to zero */
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void bn_set_all_zero(BIGNUM *a);
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/*
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* Copy the internal BIGNUM words into out which holds size elements (and size
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* must be bigger than top)
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*/
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int bn_copy_words(BN_ULONG *out, const BIGNUM *in, int size);
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BN_ULONG *bn_get_words(const BIGNUM *a);
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/*
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* Set the internal data words in a to point to words which contains size
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* elements. The BN_FLG_STATIC_DATA flag is set
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*/
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void bn_set_static_words(BIGNUM *a, BN_ULONG *words, int size);
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/*
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* Copy words into the BIGNUM |a|, reallocating space as necessary.
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* The negative flag of |a| is not modified.
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* Returns 1 on success and 0 on failure.
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*/
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/*
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* |num_words| is int because bn_expand2 takes an int. This is an internal
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* function so we simply trust callers not to pass negative values.
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*/
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int bn_set_words(BIGNUM *a, BN_ULONG *words, int num_words);
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size_t bn_sizeof_BIGNUM(void);
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/*
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* Return element el from an array of BIGNUMs starting at base (required
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* because callers do not know the size of BIGNUM at compilation time)
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*/
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BIGNUM *bn_array_el(BIGNUM *base, int el);
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#ifdef __cplusplus
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}
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#endif
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#endif
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