74924dcb38
Add secure heap for storage of private keys (when possible). Add BIO_s_secmem(), CBIGNUM, etc. Add BIO_CTX_secure_new so all BIGNUM's in the context are secure. Contributed by Akamai Technologies under the Corporate CLA. Reviewed-by: Richard Levitte <levitte@openssl.org>
70 lines
1.9 KiB
Plaintext
70 lines
1.9 KiB
Plaintext
=pod
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=head1 NAME
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BN_CTX_new, BN_CTX_secure_new, BN_CTX_init, BN_CTX_free - allocate and free BN_CTX structures
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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BN_CTX *BN_CTX_new(void);
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BN_CTX *BN_CTX_secure_new(void);
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void BN_CTX_free(BN_CTX *c);
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=head1 DESCRIPTION
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A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by
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library functions. Since dynamic memory allocation to create B<BIGNUM>s
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is rather expensive when used in conjunction with repeated subroutine
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calls, the B<BN_CTX> structure is used.
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BN_CTX_new() allocates and initializes a B<BN_CTX> structure.
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BN_CTX_secure_new() allocates and initializes a B<BN_CTX> structure
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but uses the secure heap (see L<CRYPTO_secure_malloc(3)>) to hold the
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B<BIGNUM>s.
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BN_CTX_free() frees the components of the B<BN_CTX>, and if it was
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created by BN_CTX_new(), also the structure itself.
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If L<BN_CTX_start(3)|BN_CTX_start(3)> has been used on the B<BN_CTX>,
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L<BN_CTX_end(3)|BN_CTX_end(3)> must be called before the B<BN_CTX>
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may be freed by BN_CTX_free().
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If B<c> is NULL, nothing is done.
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=head1 RETURN VALUES
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BN_CTX_new() and BN_CTX_secure_new() return a pointer to the B<BN_CTX>.
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If the allocation fails,
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they return B<NULL> and sets an error code that can be obtained by
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L<ERR_get_error(3)|ERR_get_error(3)>.
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BN_CTX_free() has no return values.
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=head1 REMOVED FUNCTIONALITY
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void BN_CTX_init(BN_CTX *c);
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BN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications should
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replace use of BN_CTX_init with BN_CTX_new instead:
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BN_CTX *ctx;
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ctx = BN_CTX_new();
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if(!ctx) /* Handle error */
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...
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BN_CTX_free(ctx);
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=head1 SEE ALSO
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L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>,
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L<BN_CTX_start(3)|BN_CTX_start(3)>
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=head1 HISTORY
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BN_CTX_new() and BN_CTX_free() are available in all versions on SSLeay
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and OpenSSL. BN_CTX_init() was added in SSLeay 0.9.1b and removed in OpenSSL
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1.1.0.
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=cut
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