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() sets the lower-level memory allocation functions
88 to their default implementation. It is generally not necessary to call
89 this, except perhaps in certain shared-library situations.
90 OPENSSL_malloc(), OPENSSL_realloc(), and OPENSSL_free() are like the C
92 malloc(), realloc(), and free() functions. OPENSSL_zalloc() calls
93 memset() to zero the memory before returning.
94 OPENSSL_clear_realloc() and OPENSSL_clear_free() should be used when
96 the buffer at addr holds sensitive information. The old buffer is
97 filled with zero's by calling OPENSSL_cleanse() before ultimately
98 calling OPENSSL_free().
99 OPENSSL_cleanse() fills ptr of size len with a string of 0's. Use
101 OPENSSL_cleanse() with care if the memory is a mapping of a file. If
102 the storage controller uses write compression, then its possible that
103 sensitive tail bytes will survive zeroization because the block of
104 zeros will be compressed. If the storage controller uses wear leveling,
105 then the old sensitive data will not be overwritten; rather, a block of
106 0's will be written at a new physical location.
107 OPENSSL_strdup(), OPENSSL_strndup() and OPENSSL_memdup() are like the
109 equivalent C functions, except that memory is allocated by calling the
110 OPENSSL_malloc() and should be released by calling OPENSSL_free().
111 OPENSSL_strlcpy(), OPENSSL_strlcat() and OPENSSL_strnlen() are
113 equivalents of the common C library functions and are provided for
114 portability.
115 OPENSSL_hexstr2buf() parses str as a hex string and returns a pointer
117 to the parsed value. The memory is allocated by calling
118 OPENSSL_malloc() and should be released by calling OPENSSL_free(). If
119 len is not NULL, it is filled in with the output length. Colons
120 between two-character hex "bytes" are ignored. An odd number of hex
121 digits is an error.
122 OPENSSL_buf2hexstr() takes the specified buffer and length, and returns
124 a hex string for value, or NULL on error. Buffer cannot be NULL; if
125 len is 0 an empty string is returned.
126 OPENSSL_hexchar2int() converts a character to the hexadecimal
128 equivalent, or returns -1 on error.
129 If no allocations have been done, it is possible to "swap out" the
131 default implementations for OPENSSL_malloc(), OPENSSL_realloc and
132 OPENSSL_free() and replace them with alternate versions (hooks).
133 CRYPTO_get_mem_functions() function fills in the given arguments with
134 the function pointers for the current implementations. With
135 CRYPTO_set_mem_functions(), you can specify a different set of
136 functions. If any of m, r, or f are NULL, then the function is not
137 changed.
138 The default implementation can include some debugging capability (if
140 enabled at build-time). This adds some overhead by keeping a list of
141 all memory allocations, and removes items from the list when they are
142 free'd. This is most useful for identifying memory leaks.
143 CRYPTO_set_mem_debug() turns this tracking on and off. In order to
144 have any effect, is must be called before any of the allocation
145 functions (e.g., CRYPTO_malloc()) are called, and is therefore normally
146 one of the first lines of main() in an application. CRYPTO_mem_ctrl()
147 provides fine-grained control of memory leak tracking. To enable
148 tracking call CRYPTO_mem_ctrl() with a mode argument of the
149 CRYPTO_MEM_CHECK_ON. To disable tracking call CRYPTO_mem_ctrl() with a
150 mode argument of the CRYPTO_MEM_CHECK_OFF.
151 While checking memory, it can be useful to store additional context
153 about what is being done. For example, identifying the field names
154 when parsing a complicated data structure. OPENSSL_mem_debug_push()
155 (which calls CRYPTO_mem_debug_push()) attachs an identifying string to
156 the allocation stack. This must be a global or other static string; it
157 is not copied. OPENSSL_mem_debug_pop() removes identifying state from
158 the stack.
159 At the end of the program, calling CRYPTO_mem_leaks() or
161 CRYPTO_mem_leaks_fp() will report all "leaked" memory, writing it to
162 the specified BIO b or FILE fp. These functions return 1 if there are
163 no leaks, 0 if there are leaks and -1 if an error occurred.
164 CRYPTO_mem_leaks_cb() does the same as CRYPTO_mem_leaks(), but instead
166 of writing to a given BIO, the callback function is called for each
167 output string with the string, length, and userdata u as the callback
168 parameters.
169 If the library is built with the "crypto-mdebug" option, then one
171 function, CRYPTO_get_alloc_counts(), and two additional environment
172 variables, OPENSSL_MALLOC_FAILURES and OPENSSL_MALLOC_FD, are
173 available.
174 The function CRYPTO_get_alloc_counts() fills in the number of times
176 each of CRYPTO_malloc(), CRYPTO_realloc(), and CRYPTO_free() have been
177 called, into the values pointed to by mcount, rcount, and fcount,
178 respectively. If a pointer is NULL, then the corresponding count is
179 not stored.
180 The variable OPENSSL_MALLOC_FAILURES controls how often allocations
182 should fail. It is a set of fields separated by semicolons, which each
183 field is a count (defaulting to zero) and an optional atsign and
184 percentage (defaulting to 100). If the count is zero, then it lasts
185 forever. For example, "100;@25" or "100@0;0@25" means the first 100
186 allocations pass, then all other allocations (until the program exits
187 or crashes) have a 25% chance of failing.
188 If the variable OPENSSL_MALLOC_FD is parsed as a positive integer, then
190 it is taken as an open file descriptor, and a record of all allocations
191 is written to that descriptor. If an allocation will fail, and the
192 platform supports it, then a backtrace will be written to the
193 descriptor. This can be useful because a malloc may fail but not be
194 checked, and problems will only occur later. The following example in
195 classic shell syntax shows how to use this (will not work on all
196 platforms):
197 OPENSSL_MALLOC_FAILURES='200;@10'
199 export OPENSSL_MALLOC_FAILURES
200 OPENSSL_MALLOC_FD=3
201 export OPENSSL_MALLOC_FD
202 ...app invocation... 3>/tmp/log$$
203
205 OPENSSL_malloc_init(), OPENSSL_free(), OPENSSL_clear_free()
206 CRYPTO_free(), CRYPTO_clear_free() and CRYPTO_get_mem_functions()
207 return no value.
208 CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp() and CRYPTO_mem_leaks_cb()
210 return 1 if there are no leaks, 0 if there are leaks and -1 if an error
211 occurred.
212 OPENSSL_malloc(), OPENSSL_zalloc(), OPENSSL_realloc(),
214 OPENSSL_clear_realloc(), CRYPTO_malloc(), CRYPTO_zalloc(),
215 CRYPTO_realloc(), CRYPTO_clear_realloc(), OPENSSL_buf2hexstr(),
216 OPENSSL_hexstr2buf(), OPENSSL_strdup(), and OPENSSL_strndup() return a
217 pointer to allocated memory or NULL on error.
218 CRYPTO_set_mem_functions() and CRYPTO_set_mem_debug() return 1 on
220 success or 0 on failure (almost always because allocations have already
221 happened).
222 CRYPTO_mem_ctrl() returns -1 if an error occurred, otherwise the
224 previous value of the mode.
225 OPENSSL_mem_debug_push() and OPENSSL_mem_debug_pop() return 1 on
227 success or 0 on failure.
228
230 While it's permitted to swap out only a few and not all the functions
231 with CRYPTO_set_mem_functions(), it's recommended to swap them all out
232 at once. This applies specially if OpenSSL was built with the
233 configuration option "crypto-mdebug" enabled. In case, swapping out
234 only, say, the malloc() implementation is outright dangerous.
235
237 Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
238 Licensed under the OpenSSL license (the "License"). You may not use
240 this file except in compliance with the License. You can obtain a copy
241 in the file LICENSE in the source distribution or at
242 <https://www.openssl.org/source/license.html>.
2431.1.1 2018-09-11 OPENSSL_MALLOC(3)