6ebb49f3f9
rand_pool_bytes_needed() was constructed in such a way that the smallest acceptable entropy factor was 1 entropy bits per 8 bits of data. At the same time, we have a DRBG_MINMAX_FACTOR that allows weaker source, as small as 1 bit of entropy per 128 bits of data. The conclusion is that rand_pool_bytes_needed() needs to change to support weaker entropy sources. We therefore change the input of entropy per byte to be an entropy factor instead. This entropy factor expresses how many bits of data it takes (on average) to get 1 bit of entropy. Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> (Merged from https://github.com/openssl/openssl/pull/6150)
114 lines
3.9 KiB
C
114 lines
3.9 KiB
C
/*
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* Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (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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* https://www.openssl.org/source/license.html
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*/
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/*
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* Licensed under the OpenSSL licenses, (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* https://www.openssl.org/source/license.html
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* or in the file LICENSE in the source distribution.
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*/
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#ifndef HEADER_RAND_INT_H
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# define HEADER_RAND_INT_H
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# include <openssl/rand.h>
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/* forward declaration */
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typedef struct rand_pool_st RAND_POOL;
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void rand_cleanup_int(void);
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void rand_drbg_cleanup_int(void);
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void drbg_delete_thread_state(void);
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void rand_fork(void);
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/* Hardware-based seeding functions. */
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size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
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size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
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/* DRBG entropy callbacks. */
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size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
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unsigned char **pout,
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int entropy, size_t min_len, size_t max_len,
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int prediction_resistance);
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void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
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unsigned char *out, size_t outlen);
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size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
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unsigned char **pout,
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int entropy, size_t min_len, size_t max_len);
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void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
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unsigned char *out, size_t outlen);
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size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len);
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void rand_drbg_cleanup_additional_data(unsigned char *out, size_t outlen);
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/*
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* RAND_POOL functions
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*/
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RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len);
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void rand_pool_free(RAND_POOL *pool);
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const unsigned char *rand_pool_buffer(RAND_POOL *pool);
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unsigned char *rand_pool_detach(RAND_POOL *pool);
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size_t rand_pool_entropy(RAND_POOL *pool);
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size_t rand_pool_length(RAND_POOL *pool);
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size_t rand_pool_entropy_available(RAND_POOL *pool);
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size_t rand_pool_entropy_needed(RAND_POOL *pool);
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/* |entropy_factor| expresses how many bits of data contain 1 bit of entropy */
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size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor);
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size_t rand_pool_bytes_remaining(RAND_POOL *pool);
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int rand_pool_add(RAND_POOL *pool,
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const unsigned char *buffer, size_t len, size_t entropy);
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unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len);
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int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy);
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/*
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* Add random bytes to the pool to acquire requested amount of entropy
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*
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* This function is platform specific and tries to acquire the requested
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* amount of entropy by polling platform specific entropy sources.
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*
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* If the function succeeds in acquiring at least |entropy_requested| bits
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* of entropy, the total entropy count is returned. If it fails, it returns
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* an entropy count of 0.
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*/
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size_t rand_pool_acquire_entropy(RAND_POOL *pool);
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/*
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* Add some application specific nonce data
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*
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* This function is platform specific and adds some application specific
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* data to the nonce used for instantiating the drbg.
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*
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* This data currently consists of the process and thread id, and a high
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* resolution timestamp. The data does not include an atomic counter,
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* because that is added by the calling function rand_drbg_get_nonce().
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*
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* Returns 1 on success and 0 on failure.
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*/
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int rand_pool_add_nonce_data(RAND_POOL *pool);
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/*
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* Add some platform specific additional data
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*
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* This function is platform specific and adds some random noise to the
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* additional data used for generating random bytes and for reseeding
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* the drbg.
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*
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* Returns 1 on success and 0 on failure.
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*/
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int rand_pool_add_additional_data(RAND_POOL *pool);
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#endif
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