aboutsummaryrefslogtreecommitdiffstats
path: root/doc/man3/OPENSSL_secure_malloc.pod
diff options
context:
space:
mode:
Diffstat (limited to 'doc/man3/OPENSSL_secure_malloc.pod')
-rw-r--r--doc/man3/OPENSSL_secure_malloc.pod134
1 files changed, 134 insertions, 0 deletions
diff --git a/doc/man3/OPENSSL_secure_malloc.pod b/doc/man3/OPENSSL_secure_malloc.pod
new file mode 100644
index 000000000000..5a01c8246933
--- /dev/null
+++ b/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
+
+OPENSSL_secure_clear_free() 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