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OPENSSL_malloc(3)                   OpenSSL                  OPENSSL_malloc(3)

       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, OPENSSL_hexstr2buf,
       OPENSSL_buf2hexstr, OPENSSL_hexchar2int, 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_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,

       libcrypto, -lcrypto

        #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);

        unsigned char *OPENSSL_hexstr2buf(const char *str, long *len);
        char *OPENSSL_buf2hexstr(const unsigned char *buffer, long len);
        int OPENSSL_hexchar2int(unsigned char c);

        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)

        void CRYPTO_get_mem_functions(
                void *(**m)(size_t, const char *, int),
                void *(**r)(void *, size_t, const char *, int),
                void (**f)(void *, const char *, int))
        int CRYPTO_set_mem_functions(
                void *(*m)(size_t, const char *, int),
                void *(*r)(void *, size_t, const char *, int),
                void (*f)(void *, const char *, int))

        void CRYPTO_get_alloc_counts(int *m, int *r, int *f)

        int CRYPTO_set_mem_debug(int onoff)

        env OPENSSL_MALLOC_FAILURES=... <application>
        env OPENSSL_MALLOC_FD=... <application>

        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);

        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);

       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 its 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

       OPENSSL_hexstr2buf() parses str as a hex string and returns a pointer
       to the parsed value. The memory is allocated by calling
       OPENSSL_malloc() and should be released by calling OPENSSL_free().  If
       len is not NULL, it is filled in with the output length.  Colons
       between two-character hex "bytes" are ignored.  An odd number of hex
       digits is an error.

       OPENSSL_buf2hexstr() takes the specified buffer and length, and returns
       a hex string for value, or NULL on error.  Buffer cannot be NULL; if
       len is 0 an empty string is returned.

       OPENSSL_hexchar2int() converts a character to the hexadecimal
       equivalent, or returns -1 on error.

       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 (hooks).
       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 m, r, or f are NULL, then the function is not

       The default implementation can include some debugging capability (if
       enabled at build-time).  This adds some overhead by keeping a list of
       all memory allocations, and removes items from the list when they are
       free'd.  This is most useful for identifying memory leaks.
       CRYPTO_set_mem_debug() turns this tracking on and off.  In order to
       have any effect, is must be called before any of the allocation
       functions (e.g., CRYPTO_malloc()) are called, and is therefore normally
       one of the first lines of main() in an application.  CRYPTO_mem_ctrl()
       provides fine-grained control of memory leak tracking.  To enable
       tracking call CRYPTO_mem_ctrl() with a mode argument of the
       CRYPTO_MEM_CHECK_ON.  To disable tracking call CRYPTO_mem_ctrl() with a
       mode argument of the CRYPTO_MEM_CHECK_OFF.

       While checking memory, it can be useful to store additional context
       about what is being done.  For example, identifying the field names
       when parsing a complicated data structure.  OPENSSL_mem_debug_push()
       (which calls CRYPTO_mem_debug_push()) attaches an identifying string to
       the allocation stack.  This must be a global or other static string; it
       is not copied.  OPENSSL_mem_debug_pop() removes identifying state from
       the stack.

       At the end of the program, calling CRYPTO_mem_leaks() or
       CRYPTO_mem_leaks_fp() will report all "leaked" memory, writing it to
       the specified BIO b or FILE fp. These functions return 1 if there are
       no leaks, 0 if there are leaks and -1 if an error occurred.

       CRYPTO_mem_leaks_cb() does the same as CRYPTO_mem_leaks(), but instead
       of writing to a given BIO, the callback function is called for each
       output string with the string, length, and userdata u as the callback

       If the library is built with the "crypto-mdebug" option, then one
       function, CRYPTO_get_alloc_counts(), and two additional environment

       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, and a record of all allocations
       is written to that descriptor.  If an allocation will fail, and the
       platform supports it, then a backtrace will be written to the
       descriptor.  This can be useful because a malloc may fail but not be
       checked, and problems will only occur later.  The following example in
       classic shell syntax shows how to use this (will not work on all

         export OPENSSL_MALLOC_FD
         ...app invocation... 3>/tmp/log$$

       OPENSSL_malloc_init(), OPENSSL_free(), OPENSSL_clear_free()
       CRYPTO_free(), CRYPTO_clear_free() and CRYPTO_get_mem_functions()
       return no value.

       CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp() and CRYPTO_mem_leaks_cb()
       return 1 if there are no leaks, 0 if there are leaks and -1 if an error

       OPENSSL_malloc(), OPENSSL_zalloc(), OPENSSL_realloc(),
       OPENSSL_clear_realloc(), CRYPTO_malloc(), CRYPTO_zalloc(),
       CRYPTO_realloc(), CRYPTO_clear_realloc(), OPENSSL_buf2hexstr(),
       OPENSSL_hexstr2buf(), OPENSSL_strdup(), and OPENSSL_strndup() return a
       pointer to allocated memory or NULL on error.

       CRYPTO_set_mem_functions() and CRYPTO_set_mem_debug() return 1 on
       success or 0 on failure (almost always because allocations have already

       CRYPTO_mem_ctrl() returns -1 if an error occurred, otherwise the
       previous value of the mode.

       OPENSSL_mem_debug_push() and OPENSSL_mem_debug_pop() return 1 on
       success or 0 on failure.

       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.  This applies specially if OpenSSL was built with the
       configuration option "crypto-mdebug" enabled.  In case, swapping out
       only, say, the mmaalllloocc(()) implementation is outright dangerous.

       Copyright 2016-2020 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

1.1.1i                            2020-03-22                 OPENSSL_malloc(3)