1=pod 2 3=head1 NAME 4 5CRYPTO_secure_malloc_init, CRYPTO_secure_malloc_initialized, 6CRYPTO_secure_malloc_done, OPENSSL_secure_malloc, CRYPTO_secure_malloc, 7OPENSSL_secure_zalloc, CRYPTO_secure_zalloc, OPENSSL_secure_free, 8CRYPTO_secure_free, OPENSSL_secure_clear_free, 9CRYPTO_secure_clear_free, OPENSSL_secure_actual_size, 10CRYPTO_secure_allocated, 11CRYPTO_secure_used - secure heap storage 12 13=head1 SYNOPSIS 14 15 #include <openssl/crypto.h> 16 17 int CRYPTO_secure_malloc_init(size_t size, int minsize); 18 19 int CRYPTO_secure_malloc_initialized(); 20 21 int CRYPTO_secure_malloc_done(); 22 23 void *OPENSSL_secure_malloc(size_t num); 24 void *CRYPTO_secure_malloc(size_t num, const char *file, int line); 25 26 void *OPENSSL_secure_zalloc(size_t num); 27 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line); 28 29 void OPENSSL_secure_free(void* ptr); 30 void CRYPTO_secure_free(void *ptr, const char *, int); 31 32 void OPENSSL_secure_clear_free(void* ptr, size_t num); 33 void CRYPTO_secure_clear_free(void *ptr, size_t num, const char *, int); 34 35 size_t OPENSSL_secure_actual_size(const void *ptr); 36 37 int CRYPTO_secure_allocated(const void *ptr); 38 size_t CRYPTO_secure_used(); 39 40=head1 DESCRIPTION 41 42In order to help protect applications (particularly long-running servers) 43from pointer overruns or underruns that could return arbitrary data from 44the program's dynamic memory area, where keys and other sensitive 45information might be stored, OpenSSL supports the concept of a "secure heap." 46The level and type of security guarantees depend on the operating system. 47It is a good idea to review the code and see if it addresses your 48threat model and concerns. 49 50If a secure heap is used, then private key B<BIGNUM> values are stored there. 51This protects long-term storage of private keys, but will not necessarily 52put all intermediate values and computations there. 53 54CRYPTO_secure_malloc_init() creates the secure heap, with the specified 55C<size> in bytes. The C<minsize> parameter is the minimum size to 56allocate from the heap. Both C<size> and C<minsize> must be a power 57of two. 58 59CRYPTO_secure_malloc_initialized() indicates whether or not the secure 60heap as been initialized and is available. 61 62CRYPTO_secure_malloc_done() releases the heap and makes the memory unavailable 63to the process if all secure memory has been freed. 64It can take noticeably long to complete. 65 66OPENSSL_secure_malloc() allocates C<num> bytes from the heap. 67If CRYPTO_secure_malloc_init() is not called, this is equivalent to 68calling OPENSSL_malloc(). 69It is a macro that expands to 70CRYPTO_secure_malloc() and adds the C<__FILE__> and C<__LINE__> parameters. 71 72OPENSSL_secure_zalloc() and CRYPTO_secure_zalloc() are like 73OPENSSL_secure_malloc() and CRYPTO_secure_malloc(), respectively, 74except that they call memset() to zero the memory before returning. 75 76OPENSSL_secure_free() releases the memory at C<ptr> back to the heap. 77It must be called with a value previously obtained from 78OPENSSL_secure_malloc(). 79If CRYPTO_secure_malloc_init() is not called, this is equivalent to 80calling OPENSSL_free(). 81It exists for consistency with OPENSSL_secure_malloc() , and 82is a macro that expands to CRYPTO_secure_free() and adds the C<__FILE__> 83and C<__LINE__> parameters.. 84 85OPENSSL_secure_clear_free() is similar to OPENSSL_secure_free() except 86that it has an additional C<num> parameter which is used to clear 87the memory if it was not allocated from the secure heap. 88If CRYPTO_secure_malloc_init() is not called, this is equivalent to 89calling OPENSSL_clear_free(). 90 91OPENSSL_secure_actual_size() tells the actual size allocated to the 92pointer; implementations may allocate more space than initially 93requested, in order to "round up" and reduce secure heap fragmentation. 94 95OPENSSL_secure_allocated() tells if a pointer is allocated in the secure heap. 96 97CRYPTO_secure_used() returns the number of bytes allocated in the 98secure heap. 99 100=head1 RETURN VALUES 101 102CRYPTO_secure_malloc_init() returns 0 on failure, 1 if successful, 103and 2 if successful but the heap could not be protected by memory 104mapping. 105 106CRYPTO_secure_malloc_initialized() returns 1 if the secure heap is 107available (that is, if CRYPTO_secure_malloc_init() has been called, 108but CRYPTO_secure_malloc_done() has not been called or failed) or 0 if not. 109 110OPENSSL_secure_malloc() and OPENSSL_secure_zalloc() return a pointer into 111the secure heap of the requested size, or C<NULL> if memory could not be 112allocated. 113 114CRYPTO_secure_allocated() returns 1 if the pointer is in the secure heap, or 0 if not. 115 116CRYPTO_secure_malloc_done() returns 1 if the secure memory area is released, or 0 if not. 117 118OPENSSL_secure_free() and OPENSSL_secure_clear_free() return no values. 119 120=head1 SEE ALSO 121 122L<OPENSSL_malloc(3)>, 123L<BN_new(3)> 124 125=head1 HISTORY 126 127The OPENSSL_secure_clear_free() function was added in OpenSSL 1.1.0g. 128 129=head1 COPYRIGHT 130 131Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. 132 133Licensed under the OpenSSL license (the "License"). You may not use 134this file except in compliance with the License. You can obtain a copy 135in the file LICENSE in the source distribution or at 136L<https://www.openssl.org/source/license.html>. 137 138=cut 139