X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frand%2Frand_lcl.h;h=c3e9804dc07e5b078379bbea30216a368f2fc9e0;hp=c96625456df9ff28f42b371998a88861aa571dfd;hb=0e2ad9593a0ff494fab3234e49499a2e68542228;hpb=a35f607c9f9112c649b367d05639394fc1c30771 diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h index c96625456d..c3e9804dc0 100644 --- a/crypto/rand/rand_lcl.h +++ b/crypto/rand/rand_lcl.h @@ -1,5 +1,5 @@ /* - * 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 * this file except in compliance with the License. You can obtain a copy @@ -15,64 +15,118 @@ # include # include # include -# include "internal/rand.h" +# include +# include "internal/tsan_assist.h" + +# include "internal/numbers.h" + +/* 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 */ + + /* - * Amount of randomness (in bytes) we want for initial seeding. - * This is based on the fact that we use AES-128 as the CRBG, and - * that we use the derivation function. If either of those changes, - * (see rand_init() in rand_lib.c), change this. + * 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 RANDOMNESS_NEEDED 16 - -/* Maximum amount of randomness to hold in RAND_BYTES_BUFFER. */ -# define MAX_RANDOMNESS_HELD (4 * RANDOMNESS_NEEDED) +# define DRBG_MAX_LENGTH INT32_MAX -/* Maximum count allowed in reseeding */ -# define MAX_RESEED (1 << 24) -/* How often we call RAND_poll() in drbg_entropy_from_system */ -# define RAND_POLL_RETRIES 8 -/* Max size of entropy, addin, etc. Larger than any reasonable value */ -# define DRBG_MAX_LENGTH 0x7ffffff0 +/* + * 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)) + */ /* DRBG status values */ typedef enum drbg_status_e { DRBG_UNINITIALISED, DRBG_READY, - DRBG_RESEED, 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); + + /* - * A buffer of random bytes to be fed as "entropy" into the DRBG. RAND_add() - * adds data to the buffer, and the drbg_entropy_from_system() pulls data from - * the buffer. We have a separate data structure because of the way the - * API is defined; otherwise we'd run into deadlocks (RAND_bytes -> - * RAND_DRBG_generate* -> drbg_entropy_from_system -> RAND_poll -> RAND_add -> - * drbg_add*; the functions with an asterisk lock). + * The DRBG methods */ -typedef struct rand_bytes_buffer_st { - CRYPTO_RWLOCK *lock; - size_t size; - size_t curr; - unsigned char *buff; -} RAND_BYTES_BUFFER; + +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; + /* * The state of a DRBG AES-CTR. */ typedef struct rand_drbg_ctr_st { - AES_KEY ks; + EVP_CIPHER_CTX *ctx; + EVP_CIPHER_CTX *ctx_df; + const 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; @@ -80,6 +134,29 @@ typedef struct rand_drbg_ctr_st { } 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 */ + + size_t min_len; /* minimum number of random bytes requested */ + size_t max_len; /* maximum number of random bytes (allocated buffer size) */ + size_t entropy; /* current entropy count in bits */ + size_t entropy_requested; /* requested entropy count in bits */ +}; + /* * The state of all types of DRBGs, even though we only have CTR mode * right now. @@ -87,33 +164,95 @@ typedef struct rand_drbg_ctr_st { struct rand_drbg_st { CRYPTO_RWLOCK *lock; RAND_DRBG *parent; - int nid; /* the underlying algorithm */ + 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 */ - unsigned short filled; + /* - * This is a fixed-size buffer, but we malloc to make it a little - * harder to find; a classic security/performance trade-off. + * 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. + * + * Currently the only type is CTR_DRBG, its init function is drbg_ctr_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. */ - int size; - unsigned char *randomness; - /* These parameters are setup by the per-type "init" function. */ int strength; 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. */ + 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; DRBG_STATUS state; /* Application data, mainly used in the KATs. */ CRYPTO_EX_DATA ex_data; - /* Implementation specific structures; was a union, but inline for now */ - RAND_DRBG_CTR ctr; + /* Implementation specific data (currently only one implementation) */ + union { + RAND_DRBG_CTR ctr; + } data; + + /* Implementation specific methods */ + RAND_DRBG_METHOD *meth; /* Callback functions. See comments in rand_lib.c */ RAND_DRBG_get_entropy_fn get_entropy; @@ -124,38 +263,31 @@ struct rand_drbg_st { /* The global RAND method, and the global buffer and DRBG instance. */ extern RAND_METHOD rand_meth; -extern RAND_BYTES_BUFFER rand_bytes; -extern RAND_DRBG rand_drbg; -extern RAND_DRBG priv_drbg; -/* How often we've forked (only incremented in child). */ +/* + * 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; -/* Hardware-based seeding functions. */ -void rand_read_tsc(RAND_poll_fn cb, void *arg); -int rand_read_cpu(RAND_poll_fn cb, void *arg); - -/* DRBG entropy callbacks. */ -void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out); -size_t drbg_entropy_from_parent(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len); -size_t drbg_entropy_from_system(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len); - -/* DRBG functions implementing AES-CTR */ -int ctr_init(RAND_DRBG *drbg); -int ctr_uninstantiate(RAND_DRBG *drbg); -int ctr_instantiate(RAND_DRBG *drbg, - const unsigned char *ent, size_t entlen, - const unsigned char *nonce, size_t noncelen, - const unsigned char *pers, size_t perslen); -int ctr_reseed(RAND_DRBG *drbg, - const unsigned char *ent, size_t entlen, - const unsigned char *adin, size_t adinlen); -int ctr_generate(RAND_DRBG *drbg, - unsigned char *out, size_t outlen, - const unsigned char *adin, size_t adinlen); +/* 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 AES-CTR DRBG implementation */ +int drbg_ctr_init(RAND_DRBG *drbg); #endif