mirror of
https://github.com/openssl/openssl.git
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e8408681b3
Fix some of the variables to be (s)size_t, so that more than 1GB of secure memory can be allocated. The arena has to be a power of 2, and 2GB fails because it ends up being a negative 32-bit signed number. The |too_late| flag is not strictly necessary; it is easy to figure out if something is secure memory by looking at the arena. As before, secure memory allocations will not fail, but now they can be freed correctly. Once initialized, secure memory can still be used, even if allocations occured before initialization. Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Rich Salz <rsalz@openssl.org>
116 lines
4.1 KiB
Plaintext
116 lines
4.1 KiB
Plaintext
=pod
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=head1 NAME
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CRYPTO_secure_malloc_init, CRYPTO_secure_malloc_initialized,
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CRYPTO_secure_malloc_done, OPENSSL_secure_malloc, CRYPTO_secure_malloc,
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OPENSSL_secure_zalloc, CRYPTO_secure_zalloc, OPENSSL_secure_free,
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CRYPTO_secure_free, OPENSSL_secure_actual_size, OPENSSL_secure_allocated,
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CYRPTO_secure_malloc_used - secure heap storage
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=head1 SYNOPSIS
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#include <openssl/crypto.h>
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int CRYPTO_secure_malloc_init(size_t size, int minsize);
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int CRYPTO_secure_malloc_initialized();
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int CRYPTO_secure_malloc_done();
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void *OPENSSL_secure_malloc(size_t num);
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void *CRYPTO_secure_malloc(size_t num, const char *file, int line);
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void *OPENSSL_secure_zalloc(size_t num);
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void *CRYPTO_secure_zalloc(size_t num, const char *file, int line);
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void OPENSSL_secure_free(void* ptr);
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void CRYPTO_secure_free(void *ptr, const char *, int);
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size_t OPENSSL_secure_actual_size(const void *ptr);
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int OPENSSL_secure_allocated(const void *ptr);
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size_t CYRPTO_secure_used();
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=head1 DESCRIPTION
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In order to help protect applications (particularly long-running servers)
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from pointer overruns or underruns that could return arbitrary data from
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the program's dynamic memory area, where keys and other sensitive
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information might be stored, OpenSSL supports the concept of a "secure heap."
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The level and type of security guarantees depend on the operating system.
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It is a good idea to review the code and see if it addresses your
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threat model and concerns.
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If a secure heap is used, then private key B<BIGNUM> values are stored there.
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This protects long-term storage of private keys, but will not necessarily
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put all intermediate values and computations there.
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CRYPTO_secure_malloc_init() creates the secure heap, with the specified
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C<size> in bytes. The C<minsize> parameter is the minimum size to
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allocate from the heap. Both C<size> and C<minsize> must be a power
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of two.
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CRYPTO_secure_malloc_initialized() indicates whether or not the secure
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heap as been initialized and is available.
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CRYPTO_secure_malloc_done() releases the heap and makes the memory unavailable
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to the process if all secure memory has been freed.
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It can take noticeably long to complete.
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OPENSSL_secure_malloc() allocates C<num> bytes from the heap.
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If CRYPTO_secure_malloc_init() is not called, this is equivalent to
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calling OPENSSL_malloc().
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It is a macro that expands to
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CRYPTO_secure_malloc() and adds the C<__FILE__> and C<__LINE__> parameters.
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OPENSSL_secure_zalloc() and CRYPTO_secure_zalloc() are like
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OPENSSL_secure_malloc() and CRYPTO_secure_malloc(), respectively,
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except that they call memset() to zero the memory before returning.
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OPENSSL_secure_free() releases the memory at C<ptr> back to the heap.
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It must be called with a value previously obtained from
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OPENSSL_secure_malloc().
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If CRYPTO_secure_malloc_init() is not called, this is equivalent to
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calling OPENSSL_free().
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It exists for consistency with OPENSSL_secure_malloc() , and
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is a macro that expands to CRYPTO_secure_free() and adds the C<__FILE__>
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and C<__LINE__> parameters..
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OPENSSL_secure_allocated() tells whether or not a pointer is within
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the secure heap.
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OPENSSL_secure_actual_size() tells the actual size allocated to the
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pointer; implementations may allocate more space than initially
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requested, in order to "round up" and reduce secure heap fragmentation.
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CRYPTO_secure_used() returns the number of bytes allocated in the
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secure heap.
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=head1 RETURN VALUES
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CRYPTO_secure_malloc_init() returns 0 on failure, 1 if successful,
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and 2 if successful but the heap could not be protected by memory
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mapping.
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CRYPTO_secure_malloc_initialized() returns 1 if the secure heap is
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available (that is, if CRYPTO_secure_malloc_init() has been called,
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but CRYPTO_secure_malloc_done() has not been called or failed) or 0 if not.
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OPENSSL_secure_malloc() and OPENSSL_secure_zalloc() return a pointer into
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the secure heap of the requested size, or C<NULL> if memory could not be
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allocated.
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CRYPTO_secure_allocated() returns 1 if the pointer is in the secure heap, or 0 if not.
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CRYPTO_secure_malloc_done() returns 1 if the secure memory area is released, or 0 if not.
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OPENSSL_secure_free() returns no values.
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=head1 SEE ALSO
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L<OPENSSL_malloc(3)>,
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L<BN_new(3)>,
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L<bn_internal(3)>.
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=cut
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