mirror of https://github.com/openssl/openssl
361 lines
13 KiB
C
361 lines
13 KiB
C
/*
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* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
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*
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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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* https://www.openssl.org/source/license.html
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*/
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#ifndef OSSL_CRYPTO_RAND_LOCAL_H
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# define OSSL_CRYPTO_RAND_LOCAL_H
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# include <openssl/aes.h>
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# include <openssl/evp.h>
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# include <openssl/sha.h>
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# include <openssl/hmac.h>
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# include <openssl/ec.h>
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# include <openssl/rand_drbg.h>
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# include "internal/tsan_assist.h"
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# include "crypto/rand.h"
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# include "internal/numbers.h"
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/* How many times to read the TSC as a randomness source. */
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# define TSC_READ_COUNT 4
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/* Maximum reseed intervals */
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# define MAX_RESEED_INTERVAL (1 << 24)
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# define MAX_RESEED_TIME_INTERVAL (1 << 20) /* approx. 12 days */
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/* Default reseed intervals */
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# define MASTER_RESEED_INTERVAL (1 << 8)
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# define SLAVE_RESEED_INTERVAL (1 << 16)
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# define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */
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# define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */
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/*
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* The number of bytes that constitutes an atomic lump of entropy with respect
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* to the FIPS 140-2 section 4.9.2 Conditional Tests. The size is somewhat
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* arbitrary, the smaller the value, the less entropy is consumed on first
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* read but the higher the probability of the test failing by accident.
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*
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* The value is in bytes.
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*/
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#define CRNGT_BUFSIZ 16
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/*
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* Maximum input size for the DRBG (entropy, nonce, personalization string)
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*
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* NIST SP800 90Ar1 allows a maximum of (1 << 35) bits i.e., (1 << 32) bytes.
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*
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* We lower it to 'only' INT32_MAX bytes, which is equivalent to 2 gigabytes.
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*/
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# define DRBG_MAX_LENGTH INT32_MAX
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/* The default nonce */
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#ifdef CHARSET_EBCDIC
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# define DRBG_DEFAULT_PERS_STRING { 0x4f, 0x70, 0x65, 0x6e, 0x53, 0x53, \
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0x4c, 0x20, 0x4e, 0x49, 0x53, 0x54, 0x20, 0x53, 0x50, 0x20, 0x38, 0x30, \
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0x30, 0x2d, 0x39, 0x30, 0x41, 0x20, 0x44, 0x52, 0x42, 0x47, 0x00};
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#else
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# define DRBG_DEFAULT_PERS_STRING "OpenSSL NIST SP 800-90A DRBG"
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#endif
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/*
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* Maximum allocation size for RANDOM_POOL buffers
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*
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* The max_len value for the buffer provided to the rand_drbg_get_entropy()
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* callback is currently 2^31 bytes (2 gigabytes), if a derivation function
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* is used. Since this is much too large to be allocated, the rand_pool_new()
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* function chooses more modest values as default pool length, bounded
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* by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH
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*
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* The choice of the RAND_POOL_FACTOR is large enough such that the
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* RAND_POOL can store a random input which has a lousy entropy rate of
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* 8/256 (= 0.03125) bits per byte. This input will be sent through the
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* derivation function which 'compresses' the low quality input into a
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* high quality output.
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*
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* The factor 1.5 below is the pessimistic estimate for the extra amount
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* of entropy required when no get_nonce() callback is defined.
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*/
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# define RAND_POOL_FACTOR 256
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# define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \
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3 * (RAND_DRBG_STRENGTH / 16))
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/*
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* = (RAND_POOL_FACTOR * \
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* 1.5 * (RAND_DRBG_STRENGTH / 8))
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*/
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/*
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* Initial allocation minimum.
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*
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* There is a distinction between the secure and normal allocation minimums.
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* Ideally, the secure allocation size should be a power of two. The normal
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* allocation size doesn't have any such restriction.
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*
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* The secure value is based on 128 bits of secure material, which is 16 bytes.
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* Typically, the DRBGs will set a minimum larger than this so optimal
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* allocation ought to take place (for full quality seed material).
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*
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* The normal value has been chosed by noticing that the rand_drbg_get_nonce
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* function is usually the largest of the built in allocation (twenty four
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* bytes and then appending another sixteen bytes). This means the buffer ends
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* with 40 bytes. The value of forty eight is comfortably above this which
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* allows some slack in the platform specific values used.
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*/
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# define RAND_POOL_MIN_ALLOCATION(secure) ((secure) ? 16 : 48)
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/* DRBG status values */
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typedef enum drbg_status_e {
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DRBG_UNINITIALISED,
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DRBG_READY,
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DRBG_ERROR
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} DRBG_STATUS;
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/* instantiate */
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typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
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const unsigned char *ent,
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size_t entlen,
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const unsigned char *nonce,
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size_t noncelen,
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const unsigned char *pers,
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size_t perslen);
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/* reseed */
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typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx,
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const unsigned char *ent,
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size_t entlen,
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const unsigned char *adin,
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size_t adinlen);
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/* generate output */
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typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
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unsigned char *out,
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size_t outlen,
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const unsigned char *adin,
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size_t adinlen);
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/* uninstantiate */
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typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx);
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/*
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* The DRBG methods
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*/
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typedef struct rand_drbg_method_st {
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RAND_DRBG_instantiate_fn instantiate;
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RAND_DRBG_reseed_fn reseed;
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RAND_DRBG_generate_fn generate;
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RAND_DRBG_uninstantiate_fn uninstantiate;
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} RAND_DRBG_METHOD;
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/* 888 bits from SP800-90Ar1 10.1 table 2 */
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#define HASH_PRNG_MAX_SEEDLEN (888/8)
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typedef struct rand_drbg_hash_st {
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EVP_MD *md;
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EVP_MD_CTX *ctx;
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size_t blocklen;
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unsigned char V[HASH_PRNG_MAX_SEEDLEN];
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unsigned char C[HASH_PRNG_MAX_SEEDLEN];
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/* Temporary value storage: should always exceed max digest length */
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unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
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} RAND_DRBG_HASH;
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typedef struct rand_drbg_hmac_st {
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EVP_MD *md;
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HMAC_CTX *ctx;
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size_t blocklen;
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unsigned char K[EVP_MAX_MD_SIZE];
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unsigned char V[EVP_MAX_MD_SIZE];
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} RAND_DRBG_HMAC;
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/*
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* The state of a DRBG AES-CTR.
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*/
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typedef struct rand_drbg_ctr_st {
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EVP_CIPHER_CTX *ctx;
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EVP_CIPHER_CTX *ctx_df;
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EVP_CIPHER *cipher;
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size_t keylen;
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unsigned char K[32];
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unsigned char V[16];
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/* Temporary block storage used by ctr_df */
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unsigned char bltmp[16];
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size_t bltmp_pos;
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unsigned char KX[48];
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} RAND_DRBG_CTR;
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/*
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* The 'random pool' acts as a dumb container for collecting random
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* input from various entropy sources. The pool has no knowledge about
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* whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
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* or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
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* random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
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* 4) cleanup the random pool again.
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*
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* The random pool contains no locking mechanism because its scope and
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* lifetime is intended to be restricted to a single stack frame.
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*/
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struct rand_pool_st {
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unsigned char *buffer; /* points to the beginning of the random pool */
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size_t len; /* current number of random bytes contained in the pool */
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int attached; /* true pool was attached to existing buffer */
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int secure; /* 1: allocated on the secure heap, 0: otherwise */
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size_t min_len; /* minimum number of random bytes requested */
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size_t max_len; /* maximum number of random bytes (allocated buffer size) */
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size_t alloc_len; /* current number of bytes allocated */
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size_t entropy; /* current entropy count in bits */
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size_t entropy_requested; /* requested entropy count in bits */
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};
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/*
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* The state of all types of DRBGs, even though we only have CTR mode
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* right now.
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*/
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struct rand_drbg_st {
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CRYPTO_RWLOCK *lock;
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/* The library context this DRBG is associated with, if any */
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OPENSSL_CTX *libctx;
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RAND_DRBG *parent;
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int secure; /* 1: allocated on the secure heap, 0: otherwise */
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int type; /* the nid of the underlying algorithm */
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/*
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* Stores the return value of openssl_get_fork_id() as of when we last
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* reseeded. The DRBG reseeds automatically whenever drbg->fork_id !=
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* openssl_get_fork_id(). Used to provide fork-safety and reseed this
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* DRBG in the child process.
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*/
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int fork_id;
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unsigned short flags; /* various external flags */
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/*
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* The random_data is used by RAND_add()/drbg_add() to attach random
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* data to the global drbg, such that the rand_drbg_get_entropy() callback
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* can pull it during instantiation and reseeding. This is necessary to
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* reconcile the different philosophies of the RAND and the RAND_DRBG
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* with respect to how randomness is added to the RNG during reseeding
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* (see PR #4328).
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*/
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struct rand_pool_st *seed_pool;
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/*
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* Auxiliary pool for additional data.
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*/
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struct rand_pool_st *adin_pool;
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/*
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* The following parameters are setup by the per-type "init" function.
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*
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* The supported types and their init functions are:
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* (1) CTR_DRBG: drbg_ctr_init().
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* (2) HMAC_DRBG: drbg_hmac_init().
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* (3) HASH_DRBG: drbg_hash_init().
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*
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* The parameters are closely related to the ones described in
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* section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
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* crucial difference: In the NIST standard, all counts are given
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* in bits, whereas in OpenSSL entropy counts are given in bits
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* and buffer lengths are given in bytes.
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*
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* Since this difference has lead to some confusion in the past,
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* (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
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* the 'len' suffix has been added to all buffer sizes for
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* clarification.
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*/
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int strength;
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size_t max_request;
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size_t min_entropylen, max_entropylen;
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size_t min_noncelen, max_noncelen;
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size_t max_perslen, max_adinlen;
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/*
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* Counts the number of generate requests since the last reseed
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* (Starts at 1). This value is the reseed_counter as defined in
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* NIST SP 800-90Ar1
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*/
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unsigned int reseed_gen_counter;
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/*
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* Maximum number of generate requests until a reseed is required.
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* This value is ignored if it is zero.
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*/
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unsigned int reseed_interval;
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/* Stores the time when the last reseeding occurred */
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time_t reseed_time;
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/*
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* Specifies the maximum time interval (in seconds) between reseeds.
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* This value is ignored if it is zero.
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*/
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time_t reseed_time_interval;
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/*
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* Counts the number of reseeds since instantiation.
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* This value is ignored if it is zero.
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*
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* This counter is used only for seed propagation from the <master> DRBG
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* to its two children, the <public> and <private> DRBG. This feature is
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* very special and its sole purpose is to ensure that any randomness which
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* is added by RAND_add() or RAND_seed() will have an immediate effect on
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* the output of RAND_bytes() resp. RAND_priv_bytes().
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*/
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TSAN_QUALIFIER unsigned int reseed_prop_counter;
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unsigned int reseed_next_counter;
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size_t seedlen;
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DRBG_STATUS state;
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/* Application data, mainly used in the KATs. */
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CRYPTO_EX_DATA ex_data;
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/* Implementation specific data */
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union {
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RAND_DRBG_CTR ctr;
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RAND_DRBG_HASH hash;
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RAND_DRBG_HMAC hmac;
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} data;
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/* Implementation specific methods */
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RAND_DRBG_METHOD *meth;
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/* Callback functions. See comments in rand_lib.c */
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RAND_DRBG_get_entropy_fn get_entropy;
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RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
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RAND_DRBG_get_nonce_fn get_nonce;
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RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
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};
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/* The global RAND method, and the global buffer and DRBG instance. */
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extern RAND_METHOD rand_meth;
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/* DRBG helpers */
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int rand_drbg_restart(RAND_DRBG *drbg,
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const unsigned char *buffer, size_t len, size_t entropy);
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size_t rand_drbg_seedlen(RAND_DRBG *drbg);
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/* locking api */
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int rand_drbg_lock(RAND_DRBG *drbg);
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int rand_drbg_unlock(RAND_DRBG *drbg);
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int rand_drbg_enable_locking(RAND_DRBG *drbg);
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/* initializes the DRBG implementation */
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int drbg_ctr_init(RAND_DRBG *drbg);
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int drbg_hash_init(RAND_DRBG *drbg);
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int drbg_hmac_init(RAND_DRBG *drbg);
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/*
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* Entropy call back for the FIPS 140-2 section 4.9.2 Conditional Tests.
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* These need to be exposed for the unit tests.
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*/
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int rand_crngt_get_entropy_cb(OPENSSL_CTX *ctx, RAND_POOL *pool,
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unsigned char *buf, unsigned char *md,
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unsigned int *md_size);
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extern int (*crngt_get_entropy)(OPENSSL_CTX *ctx, RAND_POOL *pool,
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unsigned char *buf, unsigned char *md,
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unsigned int *md_size);
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#endif
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