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_allocated, CRYPTO_secure_used -
secure heap storage
#include <openssl/crypto.h>
int CRYPTO_secure_malloc_init(size_t size, size_t 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);
int CRYPTO_secure_allocated(const void *ptr);
size_t CRYPTO_secure_used();
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
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
"size" in bytes. The "minsize" parameter is the minimum
size to allocate from the heap or zero to use a reasonable default value. Both
"size" and, if specified, "minsize" must be a power of two
and "minsize" should generally be small, for example 16 or 32.
"minsize" must be less than a quarter of "size" in any
case.
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 "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 "__FILE__" and
"__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 "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 "__FILE__" and
"__LINE__" parameters..
OPENSSL_secure_clear_free() is similar to
OPENSSL_secure_free()
except that it has an additional "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.
OPENSSL_secure_allocated() tells if a pointer is allocated in the secure
heap.
CRYPTO_secure_used() returns the number of bytes allocated in the secure
heap.
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 "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.
OPENSSL_malloc(3),
BN_new(3)
The
OPENSSL_secure_clear_free() function was added in OpenSSL 1.1.0g.
The second argument to
CRYPTO_secure_malloc_init() was changed from an
int to a
size_t in OpenSSL 3.0.
Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
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>.