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OPENSSL_malloc(3) OpenSSL OPENSSL_malloc(3)
NAME
OPENSSL_malloc_init, OPENSSL_malloc, OPENSSL_zalloc, OPENSSL_realloc,
OPENSSL_free, OPENSSL_clear_realloc, OPENSSL_clear_free,
OPENSSL_cleanse, CRYPTO_malloc, CRYPTO_zalloc, CRYPTO_realloc,
CRYPTO_free, OPENSSL_strdup, OPENSSL_strndup, OPENSSL_memdup,
OPENSSL_strlcpy, OPENSSL_strlcat, CRYPTO_strdup, CRYPTO_strndup,
OPENSSL_mem_debug_push, OPENSSL_mem_debug_pop, CRYPTO_mem_debug_push,
CRYPTO_mem_debug_pop, CRYPTO_clear_realloc, CRYPTO_clear_free,
CRYPTO_malloc_fn, CRYPTO_realloc_fn, CRYPTO_free_fn,
CRYPTO_get_mem_functions, CRYPTO_set_mem_functions,
CRYPTO_get_alloc_counts, CRYPTO_set_mem_debug, CRYPTO_mem_ctrl,
CRYPTO_mem_leaks, CRYPTO_mem_leaks_fp, CRYPTO_mem_leaks_cb,
OPENSSL_MALLOC_FAILURES, OPENSSL_MALLOC_FD - Memory allocation
functions
LIBRARY
libcrypto, -lcrypto
SYNOPSIS
#include <openssl/crypto.h>
int OPENSSL_malloc_init(void);
void *OPENSSL_malloc(size_t num);
void *OPENSSL_zalloc(size_t num);
void *OPENSSL_realloc(void *addr, size_t num);
void OPENSSL_free(void *addr);
char *OPENSSL_strdup(const char *str);
char *OPENSSL_strndup(const char *str, size_t s);
size_t OPENSSL_strlcat(char *dst, const char *src, size_t size);
size_t OPENSSL_strlcpy(char *dst, const char *src, size_t size);
void *OPENSSL_memdup(void *data, size_t s);
void *OPENSSL_clear_realloc(void *p, size_t old_len, size_t num);
void OPENSSL_clear_free(void *str, size_t num);
void OPENSSL_cleanse(void *ptr, size_t len);
void *CRYPTO_malloc(size_t num, const char *file, int line);
void *CRYPTO_zalloc(size_t num, const char *file, int line);
void *CRYPTO_realloc(void *p, size_t num, const char *file, int line);
void CRYPTO_free(void *str, const char *, int);
char *CRYPTO_strdup(const char *p, const char *file, int line);
char *CRYPTO_strndup(const char *p, size_t num, const char *file, int line);
void *CRYPTO_clear_realloc(void *p, size_t old_len, size_t num,
const char *file, int line);
void CRYPTO_clear_free(void *str, size_t num, const char *, int);
typedef void *(*CRYPTO_malloc_fn)(size_t num, const char *file, int line);
typedef void *(*CRYPTO_realloc_fn)(void *addr, size_t num, const char *file,
int line);
typedef void (*CRYPTO_free_fn)(void *addr, const char *file, int line);
void CRYPTO_get_mem_functions(CRYPTO_malloc_fn *malloc_fn,
CRYPTO_realloc_fn *realloc_fn,
CRYPTO_free_fn *free_fn);
int CRYPTO_set_mem_functions(CRYPTO_malloc_fn malloc_fn,
CRYPTO_realloc_fn realloc_fn,
CRYPTO_free_fn free_fn);
void CRYPTO_get_alloc_counts(int *mcount, int *rcount, int *fcount);
env OPENSSL_MALLOC_FAILURES=... <application>
env OPENSSL_MALLOC_FD=... <application>
The following functions have been deprecated since OpenSSL 3.0, and can
be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
version value, see openssl_user_macros(7):
int CRYPTO_mem_leaks(BIO *b);
int CRYPTO_mem_leaks_fp(FILE *fp);
int CRYPTO_mem_leaks_cb(int (*cb)(const char *str, size_t len, void *u),
void *u);
int CRYPTO_set_mem_debug(int onoff);
int CRYPTO_mem_ctrl(int mode);
int OPENSSL_mem_debug_push(const char *info);
int OPENSSL_mem_debug_pop(void);
int CRYPTO_mem_debug_push(const char *info, const char *file, int line);
int CRYPTO_mem_debug_pop(void);
DESCRIPTION
OpenSSL memory allocation is handled by the OPENSSL_xxx API. These are
generally macro's that add the standard C __FILE__ and __LINE__
parameters and call a lower-level CRYPTO_xxx API. Some functions do not
add those parameters, but exist for consistency.
OPENSSL_malloc_init() does nothing and does not need to be called. It
is included for compatibility with older versions of OpenSSL.
OPENSSL_malloc(), OPENSSL_realloc(), and OPENSSL_free() are like the C
malloc(), realloc(), and free() functions. OPENSSL_zalloc() calls
memset() to zero the memory before returning.
OPENSSL_clear_realloc() and OPENSSL_clear_free() should be used when
the buffer at addr holds sensitive information. The old buffer is
filled with zero's by calling OPENSSL_cleanse() before ultimately
calling OPENSSL_free().
OPENSSL_cleanse() fills ptr of size len with a string of 0's. Use
OPENSSL_cleanse() with care if the memory is a mapping of a file. If
the storage controller uses write compression, then it's possible that
sensitive tail bytes will survive zeroization because the block of
zeros will be compressed. If the storage controller uses wear leveling,
then the old sensitive data will not be overwritten; rather, a block of
0's will be written at a new physical location.
OPENSSL_strdup(), OPENSSL_strndup() and OPENSSL_memdup() are like the
equivalent C functions, except that memory is allocated by calling the
OPENSSL_malloc() and should be released by calling OPENSSL_free().
OPENSSL_strlcpy(), OPENSSL_strlcat() and OPENSSL_strnlen() are
equivalents of the common C library functions and are provided for
portability.
If no allocations have been done, it is possible to "swap out" the
default implementations for OPENSSL_malloc(), OPENSSL_realloc() and
OPENSSL_free() and replace them with alternate versions.
CRYPTO_get_mem_functions() function fills in the given arguments with
the function pointers for the current implementations. With
CRYPTO_set_mem_functions(), you can specify a different set of
functions. If any of malloc_fn, realloc_fn, or free_fn are NULL, then
the function is not changed. While it's permitted to swap out only a
few and not all the functions with CRYPTO_set_mem_functions(), it's
recommended to swap them all out at once.
If the library is built with the "crypto-mdebug" option, then one
function, CRYPTO_get_alloc_counts(), and two additional environment
variables, OPENSSL_MALLOC_FAILURES and OPENSSL_MALLOC_FD, are
available.
The function CRYPTO_get_alloc_counts() fills in the number of times
each of CRYPTO_malloc(), CRYPTO_realloc(), and CRYPTO_free() have been
called, into the values pointed to by mcount, rcount, and fcount,
respectively. If a pointer is NULL, then the corresponding count is
not stored.
The variable OPENSSL_MALLOC_FAILURES controls how often allocations
should fail. It is a set of fields separated by semicolons, which each
field is a count (defaulting to zero) and an optional atsign and
percentage (defaulting to 100). If the count is zero, then it lasts
forever. For example, "100;@25" or "100@0;0@25" means the first 100
allocations pass, then all other allocations (until the program exits
or crashes) have a 25% chance of failing.
If the variable OPENSSL_MALLOC_FD is parsed as a positive integer, then
it is taken as an open file descriptor. This is used in conjunction
with OPENSSL_MALLOC_FAILURES described above. For every allocation it
will log details about how many allocations there have been so far,
what percentage chance there is for this allocation failing, and
whether it has actually failed. The following example in classic shell
syntax shows how to use this (will not work on all platforms):
OPENSSL_MALLOC_FAILURES='200;@10'
export OPENSSL_MALLOC_FAILURES
OPENSSL_MALLOC_FD=3
export OPENSSL_MALLOC_FD
...app invocation... 3>/tmp/log$$
RETURN VALUES
OPENSSL_malloc_init(), OPENSSL_free(), OPENSSL_clear_free()
CRYPTO_free(), CRYPTO_clear_free() and CRYPTO_get_mem_functions()
return no value.
OPENSSL_malloc(), OPENSSL_zalloc(), OPENSSL_realloc(),
OPENSSL_clear_realloc(), CRYPTO_malloc(), CRYPTO_zalloc(),
CRYPTO_realloc(), CRYPTO_clear_realloc(), OPENSSL_strdup(), and
OPENSSL_strndup() return a pointer to allocated memory or NULL on
error.
CRYPTO_set_mem_functions() returns 1 on success or 0 on failure (almost
always because allocations have already happened).
CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp(), CRYPTO_mem_leaks_cb(),
CRYPTO_set_mem_debug(), and CRYPTO_mem_ctrl() are deprecated and are
no-ops that always return -1. OPENSSL_mem_debug_push(),
OPENSSL_mem_debug_pop(), CRYPTO_mem_debug_push(), and
CRYPTO_mem_debug_pop() are deprecated and are no-ops that always return
0.
HISTORY
OPENSSL_mem_debug_push(), OPENSSL_mem_debug_pop(),
CRYPTO_mem_debug_push(), CRYPTO_mem_debug_pop(), CRYPTO_mem_leaks(),
CRYPTO_mem_leaks_fp(), CRYPTO_mem_leaks_cb(), CRYPTO_set_mem_debug(),
CRYPTO_mem_ctrl() were deprecated in OpenSSL 3.0. The memory-leak
checking has been deprecated in OpenSSL 3.0 in favor of clang's memory
and leak sanitizer.
COPYRIGHT
Copyright 2016-2022 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>.
3.0.12 2023-05-07 OPENSSL_malloc(3)