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Diffstat (limited to 'crypto/openssl/doc/man3/OPENSSL_secure_malloc.pod')
-rw-r--r-- | crypto/openssl/doc/man3/OPENSSL_secure_malloc.pod | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/crypto/openssl/doc/man3/OPENSSL_secure_malloc.pod b/crypto/openssl/doc/man3/OPENSSL_secure_malloc.pod new file mode 100644 index 000000000000..6c395383513b --- /dev/null +++ b/crypto/openssl/doc/man3/OPENSSL_secure_malloc.pod @@ -0,0 +1,134 @@ +=pod + +=head1 NAME + +CRYPTO_secure_malloc_init, CRYPTO_secure_malloc_initialized, +CRYPTO_secure_malloc_done, OPENSSL_secure_malloc, CRYPTO_secure_malloc, +OPENSSL_secure_zalloc, CRYPTO_secure_zalloc, OPENSSL_secure_free, +CRYPTO_secure_free, OPENSSL_secure_clear_free, +CRYPTO_secure_clear_free, OPENSSL_secure_actual_size, +CRYPTO_secure_used - secure heap storage + +=head1 SYNOPSIS + + #include <openssl/crypto.h> + + int CRYPTO_secure_malloc_init(size_t size, int minsize); + + int CRYPTO_secure_malloc_initialized(); + + int CRYPTO_secure_malloc_done(); + + void *OPENSSL_secure_malloc(size_t num); + void *CRYPTO_secure_malloc(size_t num, const char *file, int line); + + void *OPENSSL_secure_zalloc(size_t num); + void *CRYPTO_secure_zalloc(size_t num, const char *file, int line); + + void OPENSSL_secure_free(void* ptr); + void CRYPTO_secure_free(void *ptr, const char *, int); + + void OPENSSL_secure_clear_free(void* ptr, size_t num); + void CRYPTO_secure_clear_free(void *ptr, size_t num, const char *, int); + + size_t OPENSSL_secure_actual_size(const void *ptr); + + size_t CRYPTO_secure_used(); + +=head1 DESCRIPTION + +In order to help protect applications (particularly long-running servers) +from pointer overruns or underruns that could return arbitrary data from +the program's dynamic memory area, where keys and other sensitive +information might be stored, OpenSSL supports the concept of a "secure heap." +The level and type of security guarantees depend on the operating system. +It is a good idea to review the code and see if it addresses your +threat model and concerns. + +If a secure heap is used, then private key B<BIGNUM> values are stored there. +This protects long-term storage of private keys, but will not necessarily +put all intermediate values and computations there. + +CRYPTO_secure_malloc_init() creates the secure heap, with the specified +C<size> in bytes. The C<minsize> parameter is the minimum size to +allocate from the heap. Both C<size> and C<minsize> must be a power +of two. + +CRYPTO_secure_malloc_initialized() indicates whether or not the secure +heap as been initialized and is available. + +CRYPTO_secure_malloc_done() releases the heap and makes the memory unavailable +to the process if all secure memory has been freed. +It can take noticeably long to complete. + +OPENSSL_secure_malloc() allocates C<num> bytes from the heap. +If CRYPTO_secure_malloc_init() is not called, this is equivalent to +calling OPENSSL_malloc(). +It is a macro that expands to +CRYPTO_secure_malloc() and adds the C<__FILE__> and C<__LINE__> parameters. + +OPENSSL_secure_zalloc() and CRYPTO_secure_zalloc() are like +OPENSSL_secure_malloc() and CRYPTO_secure_malloc(), respectively, +except that they call memset() to zero the memory before returning. + +OPENSSL_secure_free() releases the memory at C<ptr> back to the heap. +It must be called with a value previously obtained from +OPENSSL_secure_malloc(). +If CRYPTO_secure_malloc_init() is not called, this is equivalent to +calling OPENSSL_free(). +It exists for consistency with OPENSSL_secure_malloc() , and +is a macro that expands to CRYPTO_secure_free() and adds the C<__FILE__> +and C<__LINE__> parameters.. + +OPENSSL_secure_clear_free() is similar to OPENSSL_secure_free() except +that it has an additional C<num> parameter which is used to clear +the memory if it was not allocated from the secure heap. +If CRYPTO_secure_malloc_init() is not called, this is equivalent to +calling OPENSSL_clear_free(). + +OPENSSL_secure_actual_size() tells the actual size allocated to the +pointer; implementations may allocate more space than initially +requested, in order to "round up" and reduce secure heap fragmentation. + +CRYPTO_secure_used() returns the number of bytes allocated in the +secure heap. + +=head1 RETURN VALUES + +CRYPTO_secure_malloc_init() returns 0 on failure, 1 if successful, +and 2 if successful but the heap could not be protected by memory +mapping. + +CRYPTO_secure_malloc_initialized() returns 1 if the secure heap is +available (that is, if CRYPTO_secure_malloc_init() has been called, +but CRYPTO_secure_malloc_done() has not been called or failed) or 0 if not. + +OPENSSL_secure_malloc() and OPENSSL_secure_zalloc() return a pointer into +the secure heap of the requested size, or C<NULL> if memory could not be +allocated. + +CRYPTO_secure_allocated() returns 1 if the pointer is in the secure heap, or 0 if not. + +CRYPTO_secure_malloc_done() returns 1 if the secure memory area is released, or 0 if not. + +OPENSSL_secure_free() and OPENSSL_secure_clear_free() return no values. + +=head1 SEE ALSO + +L<OPENSSL_malloc(3)>, +L<BN_new(3)> + +=head1 HISTORY + +The OPENSSL_secure_clear_free() function was added in OpenSSL 1.1.0g. + +=head1 COPYRIGHT + +Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (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 +L<https://www.openssl.org/source/license.html>. + +=cut |