X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frand%2Frand_lcl.h;h=e425d41090b048be7ce9662b63958b18f47451e6;hp=0c1aa72779f6c4afa41346b8ab83d39c5988fa49;hb=a6a66e4511eec0f4ecc2943117a42b3723eb2222;hpb=f2766f753ef72dd1b0cfae9bd3b54b18795a49e4 diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h index 0c1aa72779..e425d41090 100644 --- a/crypto/rand/rand_lcl.h +++ b/crypto/rand/rand_lcl.h @@ -1,7 +1,7 @@ /* - * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved. * - * Licensed under the OpenSSL license (the "License"). You may not use + * Licensed under the Apache License 2.0 (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 * https://www.openssl.org/source/license.html @@ -15,91 +15,353 @@ # include # include # include -# include "internal/rand.h" +# include +# include "internal/tsan_assist.h" +# include "internal/rand_int.h" -/* we require 256 bits of randomness */ -# define RANDOMNESS_NEEDED (256 / 8) +# include "internal/numbers.h" -/* Maximum count allowed in reseeding */ -#define MAX_RESEED (1 << 24) +/* How many times to read the TSC as a randomness source. */ +# define TSC_READ_COUNT 4 + +/* Maximum reseed intervals */ +# define MAX_RESEED_INTERVAL (1 << 24) +# define MAX_RESEED_TIME_INTERVAL (1 << 20) /* approx. 12 days */ + +/* Default reseed intervals */ +# define MASTER_RESEED_INTERVAL (1 << 8) +# define SLAVE_RESEED_INTERVAL (1 << 16) +# define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */ +# define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */ + +/* + * The number of bytes that constitutes an atomic lump of entropy with respect + * to the FIPS 140-2 section 4.9.2 Conditional Tests. The size is somewhat + * arbitrary, the smaller the value, the less entropy is consumed on first + * read but the higher the probability of the test failing by accident. + * + * The value is in bytes. + */ +#define CRNGT_BUFSIZ 16 + +/* + * Maximum input size for the DRBG (entropy, nonce, personalization string) + * + * NIST SP800 90Ar1 allows a maximum of (1 << 35) bits i.e., (1 << 32) bytes. + * + * We lower it to 'only' INT32_MAX bytes, which is equivalent to 2 gigabytes. + */ +# define DRBG_MAX_LENGTH INT32_MAX + +/* The default nonce */ +# define DRBG_DEFAULT_PERS_STRING "OpenSSL NIST SP 800-90A DRBG" + +/* + * Maximum allocation size for RANDOM_POOL buffers + * + * The max_len value for the buffer provided to the rand_drbg_get_entropy() + * callback is currently 2^31 bytes (2 gigabytes), if a derivation function + * is used. Since this is much too large to be allocated, the rand_pool_new() + * function chooses more modest values as default pool length, bounded + * by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH + * + * The choice of the RAND_POOL_FACTOR is large enough such that the + * RAND_POOL can store a random input which has a lousy entropy rate of + * 8/256 (= 0.03125) bits per byte. This input will be sent through the + * derivation function which 'compresses' the low quality input into a + * high quality output. + * + * The factor 1.5 below is the pessimistic estimate for the extra amount + * of entropy required when no get_nonce() callback is defined. + */ +# define RAND_POOL_FACTOR 256 +# define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \ + 3 * (RAND_DRBG_STRENGTH / 16)) +/* + * = (RAND_POOL_FACTOR * \ + * 1.5 * (RAND_DRBG_STRENGTH / 8)) + */ + +/* + * Initial allocation minimum. + * + * There is a distinction between the secure and normal allocation minimums. + * Ideally, the secure allocation size should be a power of two. The normal + * allocation size doesn't have any such restriction. + * + * The secure value is based on 128 bits of secure material, which is 16 bytes. + * Typically, the DRBGs will set a minimum larger than this so optimal + * allocation ought to take place (for full quality seed material). + * + * The normal value has been chosed by noticing that the rand_drbg_get_nonce + * function is usually the largest of the built in allocation (twenty four + * bytes and then appending another sixteen bytes). This means the buffer ends + * with 40 bytes. The value of forty eight is comfortably above this which + * allows some slack in the platform specific values used. + */ +# define RAND_POOL_MIN_ALLOCATION(secure) ((secure) ? 16 : 48) /* DRBG status values */ -#define DRBG_STATUS_UNINITIALISED 0 -#define DRBG_STATUS_READY 1 -#define DRBG_STATUS_RESEED 2 -#define DRBG_STATUS_ERROR 3 +typedef enum drbg_status_e { + DRBG_UNINITIALISED, + DRBG_READY, + DRBG_ERROR +} DRBG_STATUS; + + +/* instantiate */ +typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx, + const unsigned char *ent, + size_t entlen, + const unsigned char *nonce, + size_t noncelen, + const unsigned char *pers, + size_t perslen); +/* reseed */ +typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx, + const unsigned char *ent, + size_t entlen, + const unsigned char *adin, + size_t adinlen); +/* generate output */ +typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx, + unsigned char *out, + size_t outlen, + const unsigned char *adin, + size_t adinlen); +/* uninstantiate */ +typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx); + + +/* + * The DRBG methods + */ + +typedef struct rand_drbg_method_st { + RAND_DRBG_instantiate_fn instantiate; + RAND_DRBG_reseed_fn reseed; + RAND_DRBG_generate_fn generate; + RAND_DRBG_uninstantiate_fn uninstantiate; +} RAND_DRBG_METHOD; + +/* 888 bits from SP800-90Ar1 10.1 table 2 */ +#define HASH_PRNG_MAX_SEEDLEN (888/8) -/* A default maximum length: larger than any reasonable value used in pratice */ -#define DRBG_MAX_LENGTH 0x7ffffff0 +typedef struct rand_drbg_hash_st { + EVP_MD *md; + EVP_MD_CTX *ctx; + size_t blocklen; + unsigned char V[HASH_PRNG_MAX_SEEDLEN]; + unsigned char C[HASH_PRNG_MAX_SEEDLEN]; + /* Temporary value storage: should always exceed max digest length */ + unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN]; +} RAND_DRBG_HASH; -typedef struct drbg_ctr_ctx_st { - AES_KEY ks; +typedef struct rand_drbg_hmac_st { + EVP_MD *md; + HMAC_CTX *ctx; + size_t blocklen; + unsigned char K[EVP_MAX_MD_SIZE]; + unsigned char V[EVP_MAX_MD_SIZE]; +} RAND_DRBG_HMAC; + +/* + * The state of a DRBG AES-CTR. + */ +typedef struct rand_drbg_ctr_st { + EVP_CIPHER_CTX *ctx; + EVP_CIPHER_CTX *ctx_df; + EVP_CIPHER *cipher; size_t keylen; unsigned char K[32]; unsigned char V[16]; - /* Temp variables used by derivation function */ - AES_KEY df_ks; - AES_KEY df_kxks; /* Temporary block storage used by ctr_df */ unsigned char bltmp[16]; size_t bltmp_pos; unsigned char KX[48]; -} DRBG_CTR_CTX; +} RAND_DRBG_CTR; + + +/* + * The 'random pool' acts as a dumb container for collecting random + * input from various entropy sources. The pool has no knowledge about + * whether its randomness is fed into a legacy RAND_METHOD via RAND_add() + * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the + * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and + * 4) cleanup the random pool again. + * + * The random pool contains no locking mechanism because its scope and + * lifetime is intended to be restricted to a single stack frame. + */ +struct rand_pool_st { + unsigned char *buffer; /* points to the beginning of the random pool */ + size_t len; /* current number of random bytes contained in the pool */ + + int attached; /* true pool was attached to existing buffer */ + int secure; /* 1: allocated on the secure heap, 0: otherwise */ + + size_t min_len; /* minimum number of random bytes requested */ + size_t max_len; /* maximum number of random bytes (allocated buffer size) */ + size_t alloc_len; /* current number of bytes allocated */ + size_t entropy; /* current entropy count in bits */ + size_t entropy_requested; /* requested entropy count in bits */ +}; -struct drbg_ctx_st { +/* + * The state of all types of DRBGs, even though we only have CTR mode + * right now. + */ +struct rand_drbg_st { CRYPTO_RWLOCK *lock; - DRBG_CTX *parent; - int nid; /* the NID of the underlying algorithm */ - unsigned int flags; /* various external flags */ + /* The library context this DRBG is associated with, if any */ + OPENSSL_CTX *libctx; + RAND_DRBG *parent; + int secure; /* 1: allocated on the secure heap, 0: otherwise */ + int type; /* the nid of the underlying algorithm */ + /* + * Stores the value of the rand_fork_count global as of when we last + * reseeded. The DRBG reseeds automatically whenever drbg->fork_count != + * rand_fork_count. Used to provide fork-safety and reseed this DRBG in + * the child process. + */ + int fork_count; + unsigned short flags; /* various external flags */ + + /* + * The random_data is used by RAND_add()/drbg_add() to attach random + * data to the global drbg, such that the rand_drbg_get_entropy() callback + * can pull it during instantiation and reseeding. This is necessary to + * reconcile the different philosophies of the RAND and the RAND_DRBG + * with respect to how randomness is added to the RNG during reseeding + * (see PR #4328). + */ + struct rand_pool_st *seed_pool; + + /* + * Auxiliary pool for additional data. + */ + struct rand_pool_st *adin_pool; + + /* + * The following parameters are setup by the per-type "init" function. + * + * The supported types and their init functions are: + * (1) CTR_DRBG: drbg_ctr_init(). + * (2) HMAC_DRBG: drbg_hmac_init(). + * (3) HASH_DRBG: drbg_hash_init(). + * + * The parameters are closely related to the ones described in + * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one + * crucial difference: In the NIST standard, all counts are given + * in bits, whereas in OpenSSL entropy counts are given in bits + * and buffer lengths are given in bytes. + * + * Since this difference has lead to some confusion in the past, + * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055]) + * the 'len' suffix has been added to all buffer sizes for + * clarification. + */ - /* The following parameters are setup by mechanism drbg_init() call */ int strength; - size_t blocklength; size_t max_request; - size_t min_entropy, max_entropy; - size_t min_nonce, max_nonce; - size_t max_pers, max_adin; - unsigned int reseed_counter; + size_t min_entropylen, max_entropylen; + size_t min_noncelen, max_noncelen; + size_t max_perslen, max_adinlen; + + /* + * Counts the number of generate requests since the last reseed + * (Starts at 1). This value is the reseed_counter as defined in + * NIST SP 800-90Ar1 + */ + unsigned int reseed_gen_counter; + /* + * Maximum number of generate requests until a reseed is required. + * This value is ignored if it is zero. + */ unsigned int reseed_interval; + /* Stores the time when the last reseeding occurred */ + time_t reseed_time; + /* + * Specifies the maximum time interval (in seconds) between reseeds. + * This value is ignored if it is zero. + */ + time_t reseed_time_interval; + /* + * Counts the number of reseeds since instantiation. + * This value is ignored if it is zero. + * + * This counter is used only for seed propagation from the DRBG + * to its two children, the and DRBG. This feature is + * very special and its sole purpose is to ensure that any randomness which + * is added by RAND_add() or RAND_seed() will have an immediate effect on + * the output of RAND_bytes() resp. RAND_priv_bytes(). + */ + TSAN_QUALIFIER unsigned int reseed_prop_counter; + unsigned int reseed_next_counter; + size_t seedlen; - int status; + DRBG_STATUS state; - /* Application data: typically (only?) used by test get_entropy */ + /* Application data, mainly used in the KATs. */ CRYPTO_EX_DATA ex_data; - /* Implementation specific structures */ - DRBG_CTR_CTX ctr; + /* Implementation specific data */ + union { + RAND_DRBG_CTR ctr; + RAND_DRBG_HASH hash; + RAND_DRBG_HMAC hmac; + } data; - /* entropy gathering function */ - size_t (*get_entropy)(DRBG_CTX *ctx, unsigned char **pout, - int entropy, size_t min_len, size_t max_len); - /* Indicates we have finished with entropy buffer */ - void (*cleanup_entropy)(DRBG_CTX *ctx, unsigned char *out, size_t olen); + /* Implementation specific methods */ + RAND_DRBG_METHOD *meth; - /* nonce gathering function */ - size_t (*get_nonce)(DRBG_CTX *ctx, unsigned char **pout, - int entropy, size_t min_len, size_t max_len); - /* Indicates we have finished with nonce buffer */ - void (*cleanup_nonce)(DRBG_CTX *ctx, unsigned char *out, size_t olen); + /* Callback functions. See comments in rand_lib.c */ + RAND_DRBG_get_entropy_fn get_entropy; + RAND_DRBG_cleanup_entropy_fn cleanup_entropy; + RAND_DRBG_get_nonce_fn get_nonce; + RAND_DRBG_cleanup_nonce_fn cleanup_nonce; }; +/* The global RAND method, and the global buffer and DRBG instance. */ +extern RAND_METHOD rand_meth; -extern RAND_METHOD openssl_rand_meth; -void rand_drbg_cleanup(void); - -int ctr_init(DRBG_CTX *dctx); -int drbg_hash_init(DRBG_CTX *dctx); -int drbg_hmac_init(DRBG_CTX *dctx); -int ctr_uninstantiate(DRBG_CTX *dctx); -int ctr_instantiate(DRBG_CTX *dctx, - const unsigned char *ent, size_t entlen, - const unsigned char *nonce, size_t noncelen, - const unsigned char *pers, size_t perslen); -int ctr_reseed(DRBG_CTX *dctx, - const unsigned char *ent, size_t entlen, - const unsigned char *adin, size_t adinlen); -int ctr_generate(DRBG_CTX *dctx, - unsigned char *out, size_t outlen, - const unsigned char *adin, size_t adinlen); +/* + * A "generation count" of forks. Incremented in the child process after a + * fork. Since rand_fork_count is increment-only, and only ever written to in + * the child process of the fork, which is guaranteed to be single-threaded, no + * locking is needed for normal (read) accesses; the rest of pthread fork + * processing is assumed to introduce the necessary memory barriers. Sibling + * children of a given parent will produce duplicate values, but this is not + * problematic because the reseeding process pulls input from the system CSPRNG + * and/or other global sources, so the siblings will end up generating + * different output streams. + */ +extern int rand_fork_count; + +/* DRBG helpers */ +int rand_drbg_restart(RAND_DRBG *drbg, + const unsigned char *buffer, size_t len, size_t entropy); +size_t rand_drbg_seedlen(RAND_DRBG *drbg); +/* locking api */ +int rand_drbg_lock(RAND_DRBG *drbg); +int rand_drbg_unlock(RAND_DRBG *drbg); +int rand_drbg_enable_locking(RAND_DRBG *drbg); + + +/* initializes the DRBG implementation */ +int drbg_ctr_init(RAND_DRBG *drbg); +int drbg_hash_init(RAND_DRBG *drbg); +int drbg_hmac_init(RAND_DRBG *drbg); + +/* + * Entropy call back for the FIPS 140-2 section 4.9.2 Conditional Tests. + * These need to be exposed for the unit tests. + */ +int rand_crngt_get_entropy_cb(OPENSSL_CTX *ctx, RAND_POOL *pool, + unsigned char *buf, unsigned char *md, + unsigned int *md_size); +extern int (*crngt_get_entropy)(OPENSSL_CTX *ctx, RAND_POOL *pool, + unsigned char *buf, unsigned char *md, + unsigned int *md_size); #endif