1OPENSSL_SECURE_MALLOC(3ossl) OpenSSL OPENSSL_SECURE_MALLOC(3ossl)
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6 CRYPTO_secure_malloc_init, CRYPTO_secure_malloc_initialized,
7 CRYPTO_secure_malloc_done, OPENSSL_secure_malloc, CRYPTO_secure_malloc,
8 OPENSSL_secure_zalloc, CRYPTO_secure_zalloc, OPENSSL_secure_free,
9 CRYPTO_secure_free, OPENSSL_secure_clear_free,
10 CRYPTO_secure_clear_free, OPENSSL_secure_actual_size,
11 CRYPTO_secure_allocated, CRYPTO_secure_used - secure heap storage
12
14 #include <openssl/crypto.h>
15 int CRYPTO_secure_malloc_init(size_t size, size_t minsize);
17 int CRYPTO_secure_malloc_initialized();
19 int CRYPTO_secure_malloc_done();
21 void *OPENSSL_secure_malloc(size_t num);
23 void *CRYPTO_secure_malloc(size_t num, const char *file, int line);
24 void *OPENSSL_secure_zalloc(size_t num);
26 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);
27 void OPENSSL_secure_free(void* ptr);
29 void CRYPTO_secure_free(void *ptr, const char *, int);
30 void OPENSSL_secure_clear_free(void* ptr, size_t num);
32 void CRYPTO_secure_clear_free(void *ptr, size_t num, const char *, int);
33 size_t OPENSSL_secure_actual_size(const void *ptr);
35 int CRYPTO_secure_allocated(const void *ptr);
37 size_t CRYPTO_secure_used();
38
40 In order to help protect applications (particularly long-running
41 servers) from pointer overruns or underruns that could return arbitrary
42 data from the program's dynamic memory area, where keys and other
43 sensitive information might be stored, OpenSSL supports the concept of
44 a "secure heap." The level and type of security guarantees depend on
45 the operating system. It is a good idea to review the code and see if
46 it addresses your threat model and concerns.
47 If a secure heap is used, then private key BIGNUM values are stored
49 there. This protects long-term storage of private keys, but will not
50 necessarily put all intermediate values and computations there.
51 CRYPTO_secure_malloc_init() creates the secure heap, with the specified
53 "size" in bytes. The "minsize" parameter is the minimum size to
54 allocate from the heap or zero to use a reasonable default value. Both
55 "size" and, if specified, "minsize" must be a power of two and
56 "minsize" should generally be small, for example 16 or 32. "minsize"
57 must be less than a quarter of "size" in any case.
58 CRYPTO_secure_malloc_initialized() indicates whether or not the secure
60 heap as been initialized and is available.
61 CRYPTO_secure_malloc_done() releases the heap and makes the memory
63 unavailable to the process if all secure memory has been freed. It can
64 take noticeably long to complete.
65 OPENSSL_secure_malloc() allocates "num" bytes from the heap. If
67 CRYPTO_secure_malloc_init() is not called, this is equivalent to
68 calling OPENSSL_malloc(). It is a macro that expands to
69 CRYPTO_secure_malloc() and adds the "__FILE__" and "__LINE__"
70 parameters.
71 OPENSSL_secure_zalloc() and CRYPTO_secure_zalloc() are like
73 OPENSSL_secure_malloc() and CRYPTO_secure_malloc(), respectively,
74 except that they call memset() to zero the memory before returning.
75 OPENSSL_secure_free() releases the memory at "ptr" back to the heap.
77 It must be called with a value previously obtained from
78 OPENSSL_secure_malloc(). If CRYPTO_secure_malloc_init() is not called,
79 this is equivalent to calling OPENSSL_free(). It exists for
80 consistency with OPENSSL_secure_malloc() , and is a macro that expands
81 to CRYPTO_secure_free() and adds the "__FILE__" and "__LINE__"
82 parameters..
83 OPENSSL_secure_clear_free() is similar to OPENSSL_secure_free() except
85 that it has an additional "num" parameter which is used to clear the
86 memory if it was not allocated from the secure heap. If
87 CRYPTO_secure_malloc_init() is not called, this is equivalent to
88 calling OPENSSL_clear_free().
89 OPENSSL_secure_actual_size() tells the actual size allocated to the
91 pointer; implementations may allocate more space than initially
92 requested, in order to "round up" and reduce secure heap fragmentation.
93 OPENSSL_secure_allocated() tells if a pointer is allocated in the
95 secure heap.
96 CRYPTO_secure_used() returns the number of bytes allocated in the
98 secure heap.
99
101 CRYPTO_secure_malloc_init() returns 0 on failure, 1 if successful, and
102 2 if successful but the heap could not be protected by memory mapping.
103 CRYPTO_secure_malloc_initialized() returns 1 if the secure heap is
105 available (that is, if CRYPTO_secure_malloc_init() has been called, but
106 CRYPTO_secure_malloc_done() has not been called or failed) or 0 if not.
107 OPENSSL_secure_malloc() and OPENSSL_secure_zalloc() return a pointer
109 into the secure heap of the requested size, or "NULL" if memory could
110 not be allocated.
111 CRYPTO_secure_allocated() returns 1 if the pointer is in the secure
113 heap, or 0 if not.
114 CRYPTO_secure_malloc_done() returns 1 if the secure memory area is
116 released, or 0 if not.
117 OPENSSL_secure_free() and OPENSSL_secure_clear_free() return no values.
119
121 OPENSSL_malloc(3), BN_new(3)
122
124 The OPENSSL_secure_clear_free() function was added in OpenSSL 1.1.0g.
125 The second argument to CRYPTO_secure_malloc_init() was changed from an
127 int to a size_t in OpenSSL 3.0.
128
130 Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
131 Licensed under the Apache License 2.0 (the "License"). You may not use
133 this file except in compliance with the License. You can obtain a copy
134 in the file LICENSE in the source distribution or at
135 <https://www.openssl.org/source/license.html>.
1363.1.1 2023-08-31 OPENSSL_SECURE_MALLOC(3ossl)