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2c35d61790
The documentation was misleading in that it suggests that this environment variable will record information about all allocations. While this is true it doesn't record the most useful information that you might expect such as the requested size of the allocation! It is mainly for use in conjunction with OPENSSL_MALLOC_FAILURES, and reports information about what chance an allocation has of failing. We also clarify that the mem_debug functions are actually no-ops in 3.0. Reviewed-by: Hugo Landau <hlandau@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from https://github.com/openssl/openssl/pull/18967)
209 lines
8.7 KiB
Plaintext
209 lines
8.7 KiB
Plaintext
=pod
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=head1 NAME
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OPENSSL_malloc_init,
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OPENSSL_malloc, OPENSSL_zalloc, OPENSSL_realloc, OPENSSL_free,
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OPENSSL_clear_realloc, OPENSSL_clear_free, OPENSSL_cleanse,
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CRYPTO_malloc, CRYPTO_zalloc, CRYPTO_realloc, CRYPTO_free,
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OPENSSL_strdup, OPENSSL_strndup,
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OPENSSL_memdup, OPENSSL_strlcpy, OPENSSL_strlcat,
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CRYPTO_strdup, CRYPTO_strndup,
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OPENSSL_mem_debug_push, OPENSSL_mem_debug_pop,
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CRYPTO_mem_debug_push, CRYPTO_mem_debug_pop,
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CRYPTO_clear_realloc, CRYPTO_clear_free,
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CRYPTO_malloc_fn, CRYPTO_realloc_fn, CRYPTO_free_fn,
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CRYPTO_get_mem_functions, CRYPTO_set_mem_functions,
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CRYPTO_get_alloc_counts,
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CRYPTO_set_mem_debug, CRYPTO_mem_ctrl,
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CRYPTO_mem_leaks, CRYPTO_mem_leaks_fp, CRYPTO_mem_leaks_cb,
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OPENSSL_MALLOC_FAILURES,
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OPENSSL_MALLOC_FD
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- Memory allocation functions
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=head1 SYNOPSIS
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#include <openssl/crypto.h>
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int OPENSSL_malloc_init(void);
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void *OPENSSL_malloc(size_t num);
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void *OPENSSL_zalloc(size_t num);
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void *OPENSSL_realloc(void *addr, size_t num);
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void OPENSSL_free(void *addr);
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char *OPENSSL_strdup(const char *str);
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char *OPENSSL_strndup(const char *str, size_t s);
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size_t OPENSSL_strlcat(char *dst, const char *src, size_t size);
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size_t OPENSSL_strlcpy(char *dst, const char *src, size_t size);
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void *OPENSSL_memdup(void *data, size_t s);
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void *OPENSSL_clear_realloc(void *p, size_t old_len, size_t num);
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void OPENSSL_clear_free(void *str, size_t num);
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void OPENSSL_cleanse(void *ptr, size_t len);
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void *CRYPTO_malloc(size_t num, const char *file, int line);
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void *CRYPTO_zalloc(size_t num, const char *file, int line);
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void *CRYPTO_realloc(void *p, size_t num, const char *file, int line);
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void CRYPTO_free(void *str, const char *, int);
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char *CRYPTO_strdup(const char *p, const char *file, int line);
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char *CRYPTO_strndup(const char *p, size_t num, const char *file, int line);
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void *CRYPTO_clear_realloc(void *p, size_t old_len, size_t num,
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const char *file, int line);
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void CRYPTO_clear_free(void *str, size_t num, const char *, int);
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typedef void *(*CRYPTO_malloc_fn)(size_t num, const char *file, int line);
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typedef void *(*CRYPTO_realloc_fn)(void *addr, size_t num, const char *file,
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int line);
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typedef void (*CRYPTO_free_fn)(void *addr, const char *file, int line);
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void CRYPTO_get_mem_functions(CRYPTO_malloc_fn *malloc_fn,
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CRYPTO_realloc_fn *realloc_fn,
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CRYPTO_free_fn *free_fn);
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int CRYPTO_set_mem_functions(CRYPTO_malloc_fn malloc_fn,
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CRYPTO_realloc_fn realloc_fn,
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CRYPTO_free_fn free_fn);
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void CRYPTO_get_alloc_counts(int *mcount, int *rcount, int *fcount);
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env OPENSSL_MALLOC_FAILURES=... <application>
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env OPENSSL_MALLOC_FD=... <application>
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The following functions have been deprecated since OpenSSL 3.0, and can be
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hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
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see L<openssl_user_macros(7)>:
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int CRYPTO_mem_leaks(BIO *b);
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int CRYPTO_mem_leaks_fp(FILE *fp);
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int CRYPTO_mem_leaks_cb(int (*cb)(const char *str, size_t len, void *u),
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void *u);
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int CRYPTO_set_mem_debug(int onoff);
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int CRYPTO_mem_ctrl(int mode);
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int OPENSSL_mem_debug_push(const char *info);
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int OPENSSL_mem_debug_pop(void);
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int CRYPTO_mem_debug_push(const char *info, const char *file, int line);
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int CRYPTO_mem_debug_pop(void);
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=head1 DESCRIPTION
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OpenSSL memory allocation is handled by the B<OPENSSL_xxx> API. These are
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generally macro's that add the standard C B<__FILE__> and B<__LINE__>
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parameters and call a lower-level B<CRYPTO_xxx> API.
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Some functions do not add those parameters, but exist for consistency.
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OPENSSL_malloc_init() does nothing and does not need to be called. It is
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included for compatibility with older versions of OpenSSL.
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OPENSSL_malloc(), OPENSSL_realloc(), and OPENSSL_free() are like the
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C malloc(), realloc(), and free() functions.
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OPENSSL_zalloc() calls memset() to zero the memory before returning.
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OPENSSL_clear_realloc() and OPENSSL_clear_free() should be used
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when the buffer at B<addr> holds sensitive information.
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The old buffer is filled with zero's by calling OPENSSL_cleanse()
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before ultimately calling OPENSSL_free().
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OPENSSL_cleanse() fills B<ptr> of size B<len> with a string of 0's.
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Use OPENSSL_cleanse() with care if the memory is a mapping of a file.
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If the storage controller uses write compression, then it's possible
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that sensitive tail bytes will survive zeroization because the block of
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zeros will be compressed. If the storage controller uses wear leveling,
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then the old sensitive data will not be overwritten; rather, a block of
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0's will be written at a new physical location.
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OPENSSL_strdup(), OPENSSL_strndup() and OPENSSL_memdup() are like the
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equivalent C functions, except that memory is allocated by calling the
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OPENSSL_malloc() and should be released by calling OPENSSL_free().
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OPENSSL_strlcpy(),
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OPENSSL_strlcat() and OPENSSL_strnlen() are equivalents of the common C
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library functions and are provided for portability.
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If no allocations have been done, it is possible to "swap out" the default
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implementations for OPENSSL_malloc(), OPENSSL_realloc() and OPENSSL_free()
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and replace them with alternate versions.
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CRYPTO_get_mem_functions() function fills in the given arguments with the
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function pointers for the current implementations.
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With CRYPTO_set_mem_functions(), you can specify a different set of functions.
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If any of B<malloc_fn>, B<realloc_fn>, or B<free_fn> are NULL, then
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the function is not changed.
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While it's permitted to swap out only a few and not all the functions
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with CRYPTO_set_mem_functions(), it's recommended to swap them all out
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at once.
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If the library is built with the C<crypto-mdebug> option, then one
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function, CRYPTO_get_alloc_counts(), and two additional environment
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variables, B<OPENSSL_MALLOC_FAILURES> and B<OPENSSL_MALLOC_FD>,
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are available.
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The function CRYPTO_get_alloc_counts() fills in the number of times
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each of CRYPTO_malloc(), CRYPTO_realloc(), and CRYPTO_free() have been
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called, into the values pointed to by B<mcount>, B<rcount>, and B<fcount>,
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respectively. If a pointer is NULL, then the corresponding count is not stored.
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The variable
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B<OPENSSL_MALLOC_FAILURES> controls how often allocations should fail.
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It is a set of fields separated by semicolons, which each field is a count
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(defaulting to zero) and an optional atsign and percentage (defaulting
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to 100). If the count is zero, then it lasts forever. For example,
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C<100;@25> or C<100@0;0@25> means the first 100 allocations pass, then all
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other allocations (until the program exits or crashes) have a 25% chance of
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failing.
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If the variable B<OPENSSL_MALLOC_FD> is parsed as a positive integer, then
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it is taken as an open file descriptor. This is used in conjunction with
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B<OPENSSL_MALLOC_FAILURES> described above. For every allocation it will log
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details about how many allocations there have been so far, what percentage
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chance there is for this allocation failing, and whether it has actually failed.
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The following example in classic shell syntax shows how to use this (will not
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work on all platforms):
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OPENSSL_MALLOC_FAILURES='200;@10'
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export OPENSSL_MALLOC_FAILURES
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OPENSSL_MALLOC_FD=3
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export OPENSSL_MALLOC_FD
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...app invocation... 3>/tmp/log$$
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=head1 RETURN VALUES
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OPENSSL_malloc_init(), OPENSSL_free(), OPENSSL_clear_free()
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CRYPTO_free(), CRYPTO_clear_free() and CRYPTO_get_mem_functions()
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return no value.
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OPENSSL_malloc(), OPENSSL_zalloc(), OPENSSL_realloc(),
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OPENSSL_clear_realloc(),
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CRYPTO_malloc(), CRYPTO_zalloc(), CRYPTO_realloc(),
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CRYPTO_clear_realloc(),
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OPENSSL_strdup(), and OPENSSL_strndup()
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return a pointer to allocated memory or NULL on error.
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CRYPTO_set_mem_functions() returns 1 on success or 0 on failure (almost
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always because allocations have already happened).
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CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp(), CRYPTO_mem_leaks_cb(),
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CRYPTO_set_mem_debug(), and CRYPTO_mem_ctrl() are deprecated and are no-ops that
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always return -1.
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OPENSSL_mem_debug_push(), OPENSSL_mem_debug_pop(),
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CRYPTO_mem_debug_push(), and CRYPTO_mem_debug_pop()
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are deprecated and are no-ops that always return 0.
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=head1 HISTORY
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OPENSSL_mem_debug_push(), OPENSSL_mem_debug_pop(),
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CRYPTO_mem_debug_push(), CRYPTO_mem_debug_pop(),
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CRYPTO_mem_leaks(), CRYPTO_mem_leaks_fp(),
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CRYPTO_mem_leaks_cb(), CRYPTO_set_mem_debug(), CRYPTO_mem_ctrl()
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were deprecated in OpenSSL 3.0.
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The memory-leak checking has been deprecated in OpenSSL 3.0 in favor of
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clang's memory and leak sanitizer.
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=head1 COPYRIGHT
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Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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