1OPENSSL_MALLOC(3) OpenSSL OPENSSL_MALLOC(3)
2
6 OPENSSL_malloc_init, OPENSSL_malloc, OPENSSL_zalloc, OPENSSL_realloc,
7 OPENSSL_free, OPENSSL_clear_realloc, OPENSSL_clear_free,
8 OPENSSL_cleanse, CRYPTO_malloc, CRYPTO_zalloc, CRYPTO_realloc,
9 CRYPTO_free, OPENSSL_strdup, OPENSSL_strndup, OPENSSL_memdup,
10 OPENSSL_strlcpy, OPENSSL_strlcat, OPENSSL_hexstr2buf,
11 OPENSSL_buf2hexstr, OPENSSL_hexchar2int, CRYPTO_strdup, CRYPTO_strndup,
12 OPENSSL_mem_debug_push, OPENSSL_mem_debug_pop, CRYPTO_mem_debug_push,
13 CRYPTO_mem_debug_pop, CRYPTO_clear_realloc, CRYPTO_clear_free,
14 CRYPTO_get_mem_functions, CRYPTO_set_mem_functions,
15 CRYPTO_get_alloc_counts, CRYPTO_set_mem_debug, CRYPTO_mem_ctrl,
16 CRYPTO_mem_leaks, CRYPTO_mem_leaks_fp, CRYPTO_mem_leaks_cb,
17 OPENSSL_MALLOC_FAILURES, OPENSSL_MALLOC_FD - Memory allocation
18 functions
19
21 #include <openssl/crypto.h>
22 int OPENSSL_malloc_init(void)
24 void *OPENSSL_malloc(size_t num)
26 void *OPENSSL_zalloc(size_t num)
27 void *OPENSSL_realloc(void *addr, size_t num)
28 void OPENSSL_free(void *addr)
29 char *OPENSSL_strdup(const char *str)
30 char *OPENSSL_strndup(const char *str, size_t s)
31 size_t OPENSSL_strlcat(char *dst, const char *src, size_t size);
32 size_t OPENSSL_strlcpy(char *dst, const char *src, size_t size);
33 void *OPENSSL_memdup(void *data, size_t s)
34 void *OPENSSL_clear_realloc(void *p, size_t old_len, size_t num)
35 void OPENSSL_clear_free(void *str, size_t num)
36 void OPENSSL_cleanse(void *ptr, size_t len);
37 unsigned char *OPENSSL_hexstr2buf(const char *str, long *len);
39 char *OPENSSL_buf2hexstr(const unsigned char *buffer, long len);
40 int OPENSSL_hexchar2int(unsigned char c);
41 void *CRYPTO_malloc(size_t num, const char *file, int line)
43 void *CRYPTO_zalloc(size_t num, const char *file, int line)
44 void *CRYPTO_realloc(void *p, size_t num, const char *file, int line)
45 void CRYPTO_free(void *str, const char *, int)
46 char *CRYPTO_strdup(const char *p, const char *file, int line)
47 char *CRYPTO_strndup(const char *p, size_t num, const char *file, int line)
48 void *CRYPTO_clear_realloc(void *p, size_t old_len, size_t num,
49 const char *file, int line)
50 void CRYPTO_clear_free(void *str, size_t num, const char *, int)
51 void CRYPTO_get_mem_functions(
53 void *(**m)(size_t, const char *, int),
54 void *(**r)(void *, size_t, const char *, int),
55 void (**f)(void *, const char *, int))
56 int CRYPTO_set_mem_functions(
57 void *(*m)(size_t, const char *, int),
58 void *(*r)(void *, size_t, const char *, int),
59 void (*f)(void *, const char *, int))
60 void CRYPTO_get_alloc_counts(int *m, int *r, int *f)
62 int CRYPTO_set_mem_debug(int onoff)
64 env OPENSSL_MALLOC_FAILURES=... <application>
66 env OPENSSL_MALLOC_FD=... <application>
67 int CRYPTO_mem_ctrl(int mode);
69 int OPENSSL_mem_debug_push(const char *info)
71 int OPENSSL_mem_debug_pop(void);
72 int CRYPTO_mem_debug_push(const char *info, const char *file, int line);
74 int CRYPTO_mem_debug_pop(void);
75 int CRYPTO_mem_leaks(BIO *b);
77 int CRYPTO_mem_leaks_fp(FILE *fp);
78 int CRYPTO_mem_leaks_cb(int (*cb)(const char *str, size_t len, void *u),
79 void *u);
80
82 OpenSSL memory allocation is handled by the OPENSSL_xxx API. These are
83 generally macro's that add the standard C __FILE__ and __LINE__
84 parameters and call a lower-level CRYPTO_xxx API. Some functions do
85 not add those parameters, but exist for consistency.
86 OPENSSL_malloc_init() does nothing and does not need to be called. It
88 is included for compatibility with older versions of OpenSSL.
89 OPENSSL_malloc(), OPENSSL_realloc(), and OPENSSL_free() are like the C
91 malloc(), realloc(), and free() functions. OPENSSL_zalloc() calls
92 memset() to zero the memory before returning.
93 OPENSSL_clear_realloc() and OPENSSL_clear_free() should be used when
95 the buffer at addr holds sensitive information. The old buffer is
96 filled with zero's by calling OPENSSL_cleanse() before ultimately
97 calling OPENSSL_free().
98 OPENSSL_cleanse() fills ptr of size len with a string of 0's. Use
100 OPENSSL_cleanse() with care if the memory is a mapping of a file. If
101 the storage controller uses write compression, then it's possible that
102 sensitive tail bytes will survive zeroization because the block of
103 zeros will be compressed. If the storage controller uses wear leveling,
104 then the old sensitive data will not be overwritten; rather, a block of
105 0's will be written at a new physical location.
106 OPENSSL_strdup(), OPENSSL_strndup() and OPENSSL_memdup() are like the
108 equivalent C functions, except that memory is allocated by calling the
109 OPENSSL_malloc() and should be released by calling OPENSSL_free().
110 OPENSSL_strlcpy(), OPENSSL_strlcat() and OPENSSL_strnlen() are
112 equivalents of the common C library functions and are provided for
113 portability.
114 OPENSSL_hexstr2buf() parses str as a hex string and returns a pointer
116 to the parsed value. The memory is allocated by calling
117 OPENSSL_malloc() and should be released by calling OPENSSL_free(). If
118 len is not NULL, it is filled in with the output length. Colons
119 between two-character hex "bytes" are ignored. An odd number of hex
120 digits is an error.
121 OPENSSL_buf2hexstr() takes the specified buffer and length, and returns
123 a hex string for value, or NULL on error. Buffer cannot be NULL; if
124 len is 0 an empty string is returned.
125 OPENSSL_hexchar2int() converts a character to the hexadecimal
127 equivalent, or returns -1 on error.
128 If no allocations have been done, it is possible to "swap out" the
130 default implementations for OPENSSL_malloc(), OPENSSL_realloc and
131 OPENSSL_free() and replace them with alternate versions (hooks).
132 CRYPTO_get_mem_functions() function fills in the given arguments with
133 the function pointers for the current implementations. With
134 CRYPTO_set_mem_functions(), you can specify a different set of
135 functions. If any of m, r, or f are NULL, then the function is not
136 changed.
137 The default implementation can include some debugging capability (if
139 enabled at build-time). This adds some overhead by keeping a list of
140 all memory allocations, and removes items from the list when they are
141 free'd. This is most useful for identifying memory leaks.
142 CRYPTO_set_mem_debug() turns this tracking on and off. In order to
143 have any effect, is must be called before any of the allocation
144 functions (e.g., CRYPTO_malloc()) are called, and is therefore normally
145 one of the first lines of main() in an application. CRYPTO_mem_ctrl()
146 provides fine-grained control of memory leak tracking. To enable
147 tracking call CRYPTO_mem_ctrl() with a mode argument of the
148 CRYPTO_MEM_CHECK_ON. To disable tracking call CRYPTO_mem_ctrl() with a
149 mode argument of the CRYPTO_MEM_CHECK_OFF.
150 While checking memory, it can be useful to store additional context
152 about what is being done. For example, identifying the field names
153 when parsing a complicated data structure. OPENSSL_mem_debug_push()
154 (which calls CRYPTO_mem_debug_push()) attaches an identifying string to
155 the allocation stack. This must be a global or other static string; it
156 is not copied. OPENSSL_mem_debug_pop() removes identifying state from
157 the stack.
158 At the end of the program, calling CRYPTO_mem_leaks() or
160 CRYPTO_mem_leaks_fp() will report all "leaked" memory, writing it to
161 the specified BIO b or FILE fp. These functions return 1 if there are
162 no leaks, 0 if there are leaks and -1 if an error occurred.
163 CRYPTO_mem_leaks_cb() does the same as CRYPTO_mem_leaks(), but instead
165 of writing to a given BIO, the callback function is called for each
166 output string with the string, length, and userdata u as the callback
167 parameters.
168 If the library is built with the "crypto-mdebug" option, then one
170 function, CRYPTO_get_alloc_counts(), and two additional environment
171 variables, OPENSSL_MALLOC_FAILURES and OPENSSL_MALLOC_FD, are
172 available.
173 The function CRYPTO_get_alloc_counts() fills in the number of times
175 each of CRYPTO_malloc(), CRYPTO_realloc(), and CRYPTO_free() have been
176 called, into the values pointed to by mcount, rcount, and fcount,
177 respectively. If a pointer is NULL, then the corresponding count is
178 not stored.
179 The variable OPENSSL_MALLOC_FAILURES controls how often allocations
181 should fail. It is a set of fields separated by semicolons, which each
182 field is a count (defaulting to zero) and an optional atsign and
183 percentage (defaulting to 100). If the count is zero, then it lasts
184 forever. For example, "100;@25" or "100@0;0@25" means the first 100
185 allocations pass, then all other allocations (until the program exits
186 or crashes) have a 25% chance of failing.
187 If the variable OPENSSL_MALLOC_FD is parsed as a positive integer, then
189 it is taken as an open file descriptor, and a record of all allocations
190 is written to that descriptor. If an allocation will fail, and the
191 platform supports it, then a backtrace will be written to the
192 descriptor. This can be useful because a malloc may fail but not be
193 checked, and problems will only occur later. The following example in
194 classic shell syntax shows how to use this (will not work on all
195 platforms):
196 OPENSSL_MALLOC_FAILURES='200;@10'
198 export OPENSSL_MALLOC_FAILURES
199 OPENSSL_MALLOC_FD=3
200 export OPENSSL_MALLOC_FD
201 ...app invocation... 3>/tmp/log$$
202
204 OPENSSL_malloc_init(), OPENSSL_free(), OPENSSL_clear_free()
205 CRYPTO_free(), CRYPTO_clear_free() and CRYPTO_get_mem_functions()
206 return no value.
207 CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp() and CRYPTO_mem_leaks_cb()
209 return 1 if there are no leaks, 0 if there are leaks and -1 if an error
210 occurred.
211 OPENSSL_malloc(), OPENSSL_zalloc(), OPENSSL_realloc(),
213 OPENSSL_clear_realloc(), CRYPTO_malloc(), CRYPTO_zalloc(),
214 CRYPTO_realloc(), CRYPTO_clear_realloc(), OPENSSL_buf2hexstr(),
215 OPENSSL_hexstr2buf(), OPENSSL_strdup(), and OPENSSL_strndup() return a
216 pointer to allocated memory or NULL on error.
217 CRYPTO_set_mem_functions() and CRYPTO_set_mem_debug() return 1 on
219 success or 0 on failure (almost always because allocations have already
220 happened).
221 CRYPTO_mem_ctrl() returns -1 if an error occurred, otherwise the
223 previous value of the mode.
224 OPENSSL_mem_debug_push() and OPENSSL_mem_debug_pop() return 1 on
226 success or 0 on failure.
227
229 While it's permitted to swap out only a few and not all the functions
230 with CRYPTO_set_mem_functions(), it's recommended to swap them all out
231 at once. This applies specially if OpenSSL was built with the
232 configuration option "crypto-mdebug" enabled. In case, swapping out
233 only, say, the malloc() implementation is outright dangerous.
234
236 Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
237 Licensed under the OpenSSL license (the "License"). You may not use
239 this file except in compliance with the License. You can obtain a copy
240 in the file LICENSE in the source distribution or at
241 <https://www.openssl.org/source/license.html>.
2421.1.1q 2023-07-20 OPENSSL_MALLOC(3)