X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frand%2Frand_lib.c;h=defa3ecb538cfaf3b8039c39d1cf7727ea9c4396;hp=909f30426fda5415ff677b971a68c98ab17e1fd2;hb=7caf122e717e79afcb986fe217e77a630b67bf4c;hpb=4871fa49cdd0d4473b6a815fc01fbde3e6ced339 diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c index 909f30426f..defa3ecb53 100644 --- a/crypto/rand/rand_lib.c +++ b/crypto/rand/rand_lib.c @@ -1,5 +1,5 @@ /* - * Copyright 1995-2017 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 @@ -15,6 +15,48 @@ #include #include "internal/thread_once.h" #include "rand_lcl.h" +#ifdef OPENSSL_SYS_UNIX +# include +# include +# include +#endif +#include "e_os.h" + +/* Macro to convert two thirty two bit values into a sixty four bit one */ +#define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b)) + +/* + * Check for the existence and support of POSIX timers. The standard + * says that the _POSIX_TIMERS macro will have a positive value if they + * are available. + * + * However, we want an additional constraint: that the timer support does + * not require an extra library dependency. Early versions of glibc + * require -lrt to be specified on the link line to access the timers, + * so this needs to be checked for. + * + * It is worse because some libraries define __GLIBC__ but don't + * support the version testing macro (e.g. uClibc). This means + * an extra check is needed. + * + * The final condition is: + * "have posix timers and either not glibc or glibc without -lrt" + * + * The nested #if sequences are required to avoid using a parameterised + * macro that might be undefined. + */ +#undef OSSL_POSIX_TIMER_OKAY +#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0 +# if defined(__GLIBC__) +# if defined(__GLIBC_PREREQ) +# if __GLIBC_PREREQ(2, 17) +# define OSSL_POSIX_TIMER_OKAY +# endif +# endif +# else +# define OSSL_POSIX_TIMER_OKAY +# endif +#endif #ifndef OPENSSL_NO_ENGINE /* non-NULL if default_RAND_meth is ENGINE-provided */ @@ -24,7 +66,7 @@ static CRYPTO_RWLOCK *rand_engine_lock; static CRYPTO_RWLOCK *rand_meth_lock; static const RAND_METHOD *default_RAND_meth; static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT; -RAND_BYTES_BUFFER rand_bytes; + int rand_fork_count; #ifdef OPENSSL_RAND_SEED_RDTSC @@ -37,12 +79,15 @@ int rand_fork_count; # error "RDTSC enabled? Should not be possible!" /* + * Acquire entropy from high-speed clock + * * Since we get some randomness from the low-order bits of the - * high-speec clock, it can help. But don't return a status since - * it's not sufficient to indicate whether or not the seeding was - * done. + * high-speed clock, it can help. + * + * Returns the total entropy count, if it exceeds the requested + * entropy count. Otherwise, returns an entropy count of 0. */ -void rand_read_tsc(RAND_poll_cb rand_add, void *arg) +size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool) { unsigned char c; int i; @@ -50,160 +95,290 @@ void rand_read_tsc(RAND_poll_cb rand_add, void *arg) if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) { for (i = 0; i < TSC_READ_COUNT; i++) { c = (unsigned char)(OPENSSL_rdtsc() & 0xFF); - rand_add(arg, &c, 1, 0.5); + rand_pool_add(pool, &c, 1, 4); } } + return rand_pool_entropy_available(pool); } #endif #ifdef OPENSSL_RAND_SEED_RDCPU -size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len); -size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len); +size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len); +size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len); extern unsigned int OPENSSL_ia32cap_P[]; -int rand_read_cpu(RAND_poll_cb rand_add, void *arg) +/* + * Acquire entropy using Intel-specific cpu instructions + * + * Uses the RDSEED instruction if available, otherwise uses + * RDRAND if available. + * + * For the differences between RDSEED and RDRAND, and why RDSEED + * is the preferred choice, see https://goo.gl/oK3KcN + * + * Returns the total entropy count, if it exceeds the requested + * entropy count. Otherwise, returns an entropy count of 0. + */ +size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool) { - char buff[RANDOMNESS_NEEDED]; - - /* If RDSEED is available, use that. */ - if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) { - if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) { - rand_add(arg, buff, (int)sizeof(buff), sizeof(buff)); - return 1; + size_t bytes_needed; + unsigned char *buffer; + + bytes_needed = rand_pool_bytes_needed(pool, 8 /*entropy_per_byte*/); + if (bytes_needed > 0) { + buffer = rand_pool_add_begin(pool, bytes_needed); + + if (buffer != NULL) { + + /* If RDSEED is available, use that. */ + if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) { + if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed) + == bytes_needed) + return rand_pool_add_end(pool, + bytes_needed, + 8 * bytes_needed); + } + + /* Second choice is RDRAND. */ + if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) { + if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed) + == bytes_needed) + return rand_pool_add_end(pool, + bytes_needed, + 8 * bytes_needed); + } + + return rand_pool_add_end(pool, 0, 0); } } - /* Second choice is RDRAND. */ - if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) { - if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) { - rand_add(arg, buff, (int)sizeof(buff), sizeof(buff)); - return 1; - } - } - - return 0; + return rand_pool_entropy_available(pool); } #endif /* - * DRBG has two sets of callbacks; we only discuss the "entropy" one - * here. When the DRBG needs additional randomness bits (called entropy - * in the NIST document), it calls the get_entropy callback which fills in - * a pointer and returns the number of bytes. When the DRBG is finished with - * the buffer, it calls the cleanup_entropy callback, with the value of - * the buffer that the get_entropy callback filled in. + * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks()) * - * Get entropy from the system, via RAND_poll if needed. The |entropy| - * is the bits of randomness required, and is expected to fit into a buffer - * of |min_len|..|max__len| size. We assume we're getting high-quality - * randomness from the system, and that |min_len| bytes will do. + * If the DRBG has a parent, then the required amount of entropy input + * is fetched using the parent's RAND_DRBG_generate(). + * + * Otherwise, the entropy is polled from the system entropy sources + * using rand_pool_acquire_entropy(). + * + * If a random pool has been added to the DRBG using RAND_add(), then + * its entropy will be used up first. */ -size_t drbg_entropy_from_system(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len) +size_t rand_drbg_get_entropy(RAND_DRBG *drbg, + unsigned char **pout, + int entropy, size_t min_len, size_t max_len, + int prediction_resistance) { - int i; + size_t ret = 0; + size_t entropy_available = 0; + RAND_POOL *pool; + + if (drbg->parent && drbg->strength > drbg->parent->strength) { + /* + * We currently don't support the algorithm from NIST SP 800-90C + * 10.1.2 to use a weaker DRBG as source + */ + RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_R_PARENT_STRENGTH_TOO_WEAK); + return 0; + } + pool = rand_pool_new(entropy, min_len, max_len); + if (pool == NULL) + return 0; - if (min_len > (size_t)drbg->size) { - /* Should not happen. See comment near RANDOMNESS_NEEDED. */ - min_len = drbg->size; + if (drbg->pool) { + rand_pool_add(pool, + rand_pool_buffer(drbg->pool), + rand_pool_length(drbg->pool), + rand_pool_entropy(drbg->pool)); + rand_pool_free(drbg->pool); + drbg->pool = NULL; } - if (drbg->filled) { - /* Re-use what we have. */ - *pout = drbg->randomness; - return drbg->size; - } + if (drbg->parent) { + size_t bytes_needed = rand_pool_bytes_needed(pool, 8); + unsigned char *buffer = rand_pool_add_begin(pool, bytes_needed); + + if (buffer != NULL) { + size_t bytes = 0; + + /* + * Get random from parent, include our state as additional input. + * Our lock is already held, but we need to lock our parent before + * generating bits from it. (Note: taking the lock will be a no-op + * if locking if drbg->parent->lock == NULL.) + */ + rand_drbg_lock(drbg->parent); + if (RAND_DRBG_generate(drbg->parent, + buffer, bytes_needed, + prediction_resistance, + (unsigned char *)drbg, sizeof(*drbg)) != 0) + bytes = bytes_needed; + rand_drbg_unlock(drbg->parent); + + entropy_available = rand_pool_add_end(pool, bytes, 8 * bytes); + } - drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size) - : OPENSSL_malloc(drbg->size); + } else { + if (prediction_resistance) { + /* + * We don't have any entropy sources that comply with the NIST + * standard to provide prediction resistance (see NIST SP 800-90C, + * Section 5.4). + */ + RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, + RAND_R_PREDICTION_RESISTANCE_NOT_SUPPORTED); + return 0; + } - /* If we don't have enough, try to get more. */ - CRYPTO_THREAD_write_lock(rand_bytes.lock); - for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) { - CRYPTO_THREAD_unlock(rand_bytes.lock); - RAND_poll(); - CRYPTO_THREAD_write_lock(rand_bytes.lock); + /* Get entropy by polling system entropy sources. */ + entropy_available = rand_pool_acquire_entropy(pool); } - /* Get desired amount, but no more than we have. */ - if (min_len > rand_bytes.curr) - min_len = rand_bytes.curr; - if (min_len != 0) { - memcpy(drbg->randomness, rand_bytes.buff, min_len); - drbg->filled = 1; - /* Update amount left and shift it down. */ - rand_bytes.curr -= min_len; - if (rand_bytes.curr != 0) - memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr); + if (entropy_available > 0) { + ret = rand_pool_length(pool); + *pout = rand_pool_detach(pool); } - CRYPTO_THREAD_unlock(rand_bytes.lock); - *pout = drbg->randomness; - return min_len; + + rand_pool_free(pool); + return ret; } -size_t drbg_entropy_from_parent(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len) +/* + * Find a suitable source of time. Start with the highest resolution source + * and work down to the slower ones. This is added as additional data and + * isn't counted as randomness, so any result is acceptable. + * + * Returns 0 when we weren't able to find any time source + */ +static uint64_t get_timer_bits(void) { - int st; + uint64_t res = OPENSSL_rdtsc(); + + if (res != 0) + return res; +#if defined(_WIN32) + { + LARGE_INTEGER t; + FILETIME ft; + + if (QueryPerformanceCounter(&t) != 0) + return t.QuadPart; + GetSystemTimeAsFileTime(&ft); + return TWO32TO64(ft.dwHighDateTime, ft.dwLowDateTime); + } +#elif defined(__sun) || defined(__hpux) + return gethrtime(); +#elif defined(_AIX) + { + timebasestruct_t t; + + read_wall_time(&t, TIMEBASE_SZ); + return TWO32TO64(t.tb_high, t.tb_low); + } +#else - if (min_len > (size_t)drbg->size) { - /* Should not happen. See comment near RANDOMNESS_NEEDED. */ - min_len = drbg->size; +# if defined(OSSL_POSIX_TIMER_OKAY) + { + struct timespec ts; + clockid_t cid; + +# ifdef CLOCK_BOOTTIME + cid = CLOCK_BOOTTIME; +# elif defined(_POSIX_MONOTONIC_CLOCK) + cid = CLOCK_MONOTONIC; +# else + cid = CLOCK_REALTIME; +# endif + + if (clock_gettime(cid, &ts) == 0) + return TWO32TO64(ts.tv_sec, ts.tv_nsec); } +# endif +# if defined(__unix__) \ + || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L) + { + struct timeval tv; + + if (gettimeofday(&tv, NULL) == 0) + return TWO32TO64(tv.tv_sec, tv.tv_usec); + } +# endif + { + time_t t = time(NULL); + if (t == (time_t)-1) + return 0; + return t; + } +#endif +} - drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size) - : OPENSSL_malloc(drbg->size); +/* + * Generate additional data that can be used for the drbg. The data does + * not need to contain entropy, but it's useful if it contains at least + * some bits that are unpredictable. + * + * Returns 0 on failure. + * + * On success it allocates a buffer at |*pout| and returns the length of + * the data. The buffer should get freed using OPENSSL_secure_clear_free(). + */ +size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len) +{ + RAND_POOL *pool; + CRYPTO_THREAD_ID thread_id; + size_t len; +#ifdef OPENSSL_SYS_UNIX + pid_t pid; +#elif defined(OPENSSL_SYS_WIN32) + DWORD pid; +#endif + uint64_t tbits; - /* Get random from parent, include our state as additional input. */ - st = RAND_DRBG_generate(drbg->parent, drbg->randomness, min_len, 0, - (unsigned char *)drbg, sizeof(*drbg)); - if (st == 0) + pool = rand_pool_new(0, 0, max_len); + if (pool == NULL) return 0; - drbg->filled = 1; - *pout = drbg->randomness; - return min_len; -} -void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out) -{ - drbg->filled = 0; - if (drbg->secure) - OPENSSL_secure_clear_free(drbg->randomness, drbg->size); - else - OPENSSL_clear_free(drbg->randomness, drbg->size); - drbg->randomness = NULL; -} +#ifdef OPENSSL_SYS_UNIX + pid = getpid(); + rand_pool_add(pool, (unsigned char *)&pid, sizeof(pid), 0); +#elif defined(OPENSSL_SYS_WIN32) + pid = GetCurrentProcessId(); + rand_pool_add(pool, (unsigned char *)&pid, sizeof(pid), 0); +#endif + thread_id = CRYPTO_THREAD_get_current_id(); + if (thread_id != 0) + rand_pool_add(pool, (unsigned char *)&thread_id, sizeof(thread_id), 0); -/* - * Set up a global DRBG. - */ -static int setup_drbg(RAND_DRBG *drbg) -{ - int ret = 1; + tbits = get_timer_bits(); + if (tbits != 0) + rand_pool_add(pool, (unsigned char *)&tbits, sizeof(tbits), 0); - drbg->lock = CRYPTO_THREAD_lock_new(); - ret &= drbg->lock != NULL; - drbg->size = RANDOMNESS_NEEDED; - drbg->secure = CRYPTO_secure_malloc_initialized(); - drbg->randomness = NULL; - /* If you change these parameters, see RANDOMNESS_NEEDED */ - ret &= RAND_DRBG_set(drbg, - NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1; - ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system, - drbg_release_entropy, NULL, NULL) == 1; - return ret; + /* TODO: Use RDSEED? */ + + len = rand_pool_length(pool); + if (len != 0) + *pout = rand_pool_detach(pool); + rand_pool_free(pool); + + return len; } -static void free_drbg(RAND_DRBG *drbg) +/* + * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks()) + * + */ +void rand_drbg_cleanup_entropy(RAND_DRBG *drbg, + unsigned char *out, size_t outlen) { - CRYPTO_THREAD_lock_free(drbg->lock); - RAND_DRBG_uninstantiate(drbg); + OPENSSL_secure_clear_free(out, outlen); } void rand_fork() @@ -222,17 +397,6 @@ DEFINE_RUN_ONCE_STATIC(do_rand_init) rand_meth_lock = CRYPTO_THREAD_lock_new(); ret &= rand_meth_lock != NULL; - rand_bytes.lock = CRYPTO_THREAD_lock_new(); - ret &= rand_bytes.lock != NULL; - rand_bytes.curr = 0; - rand_bytes.size = MAX_RANDOMNESS_HELD; - rand_bytes.secure = CRYPTO_secure_malloc_initialized(); - rand_bytes.buff = rand_bytes.secure - ? OPENSSL_secure_malloc(rand_bytes.size) - : OPENSSL_malloc(rand_bytes.size); - ret &= rand_bytes.buff != NULL; - ret &= setup_drbg(&rand_drbg); - ret &= setup_drbg(&priv_drbg); return ret; } @@ -247,27 +411,314 @@ void rand_cleanup_int(void) CRYPTO_THREAD_lock_free(rand_engine_lock); #endif CRYPTO_THREAD_lock_free(rand_meth_lock); - CRYPTO_THREAD_lock_free(rand_bytes.lock); - if (rand_bytes.secure) - OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size); - else - OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size); - free_drbg(&rand_drbg); - free_drbg(&priv_drbg); } /* - * RAND_poll_ex() gets a function pointer to call when it has random bytes. - * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add(). + * RAND_poll() reseeds the default RNG using random input + * + * The random input is obtained from polling various entropy + * sources which depend on the operating system and are + * configurable via the --with-rand-seed configure option. */ -static void call_rand_add(void* arg, const void *buf, int num, double r) +int RAND_poll(void) { - RAND_add(buf, num, r); + int ret = 0; + + RAND_POOL *pool = NULL; + + const RAND_METHOD *meth = RAND_get_rand_method(); + + if (meth == RAND_OpenSSL()) { + /* fill random pool and seed the master DRBG */ + RAND_DRBG *drbg = RAND_DRBG_get0_master(); + + if (drbg == NULL) + return 0; + + rand_drbg_lock(drbg); + ret = rand_drbg_restart(drbg, NULL, 0, 0); + rand_drbg_unlock(drbg); + + return ret; + + } else { + /* fill random pool and seed the current legacy RNG */ + pool = rand_pool_new(RAND_DRBG_STRENGTH, + RAND_DRBG_STRENGTH / 8, + DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8)); + if (pool == NULL) + return 0; + + if (rand_pool_acquire_entropy(pool) == 0) + goto err; + + if (meth->add == NULL + || meth->add(rand_pool_buffer(pool), + rand_pool_length(pool), + (rand_pool_entropy(pool) / 8.0)) == 0) + goto err; + + ret = 1; + } + +err: + rand_pool_free(pool); + return ret; } -int RAND_poll(void) +/* + * 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 */ + + 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 requested_entropy; /* requested entropy count in bits */ +}; + +/* + * Allocate memory and initialize a new random pool + */ + +RAND_POOL *rand_pool_new(int entropy, size_t min_len, size_t max_len) { - return RAND_poll_ex(call_rand_add, NULL); + RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool)); + + if (pool == NULL) { + RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE); + goto err; + } + + pool->min_len = min_len; + pool->max_len = max_len; + + pool->buffer = OPENSSL_secure_zalloc(pool->max_len); + if (pool->buffer == NULL) { + RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE); + goto err; + } + + pool->requested_entropy = entropy; + + return pool; + +err: + OPENSSL_free(pool); + return NULL; +} + +/* + * Free |pool|, securely erasing its buffer. + */ +void rand_pool_free(RAND_POOL *pool) +{ + if (pool == NULL) + return; + + OPENSSL_secure_clear_free(pool->buffer, pool->max_len); + OPENSSL_free(pool); +} + +/* + * Return the |pool|'s buffer to the caller (readonly). + */ +const unsigned char *rand_pool_buffer(RAND_POOL *pool) +{ + return pool->buffer; +} + +/* + * Return the |pool|'s entropy to the caller. + */ +size_t rand_pool_entropy(RAND_POOL *pool) +{ + return pool->entropy; +} + +/* + * Return the |pool|'s buffer length to the caller. + */ +size_t rand_pool_length(RAND_POOL *pool) +{ + return pool->len; +} + +/* + * Detach the |pool| buffer and return it to the caller. + * It's the responsibility of the caller to free the buffer + * using OPENSSL_secure_clear_free(). + */ +unsigned char *rand_pool_detach(RAND_POOL *pool) +{ + unsigned char *ret = pool->buffer; + pool->buffer = NULL; + return ret; +} + + +/* + * If every byte of the input contains |entropy_per_bytes| bits of entropy, + * how many bytes does one need to obtain at least |bits| bits of entropy? + */ +#define ENTROPY_TO_BYTES(bits, entropy_per_bytes) \ + (((bits) + ((entropy_per_bytes) - 1))/(entropy_per_bytes)) + + +/* + * Checks whether the |pool|'s entropy is available to the caller. + * This is the case when entropy count and buffer length are high enough. + * Returns + * + * |entropy| if the entropy count and buffer size is large enough + * 0 otherwise + */ +size_t rand_pool_entropy_available(RAND_POOL *pool) +{ + if (pool->entropy < pool->requested_entropy) + return 0; + + if (pool->len < pool->min_len) + return 0; + + return pool->entropy; +} + +/* + * Returns the (remaining) amount of entropy needed to fill + * the random pool. + */ + +size_t rand_pool_entropy_needed(RAND_POOL *pool) +{ + if (pool->entropy < pool->requested_entropy) + return pool->requested_entropy - pool->entropy; + + return 0; +} + +/* + * Returns the number of bytes needed to fill the pool, assuming + * the input has 'entropy_per_byte' entropy bits per byte. + * In case of an error, 0 is returned. + */ + +size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte) +{ + size_t bytes_needed; + size_t entropy_needed = rand_pool_entropy_needed(pool); + + if (entropy_per_byte < 1 || entropy_per_byte > 8) { + RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE); + return 0; + } + + bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_per_byte); + + if (bytes_needed > pool->max_len - pool->len) { + /* not enough space left */ + RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW); + return 0; + } + + if (pool->len < pool->min_len && + bytes_needed < pool->min_len - pool->len) + /* to meet the min_len requirement */ + bytes_needed = pool->min_len - pool->len; + + return bytes_needed; +} + +/* Returns the remaining number of bytes available */ +size_t rand_pool_bytes_remaining(RAND_POOL *pool) +{ + return pool->max_len - pool->len; +} + +/* + * Add random bytes to the random pool. + * + * It is expected that the |buffer| contains |len| bytes of + * random input which contains at least |entropy| bits of + * randomness. + * + * Return available amount of entropy after this operation. + * (see rand_pool_entropy_available(pool)) + */ +size_t rand_pool_add(RAND_POOL *pool, + const unsigned char *buffer, size_t len, size_t entropy) +{ + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG); + return 0; + } + + if (len > 0) { + memcpy(pool->buffer + pool->len, buffer, len); + pool->len += len; + pool->entropy += entropy; + } + + return rand_pool_entropy_available(pool); +} + +/* + * Start to add random bytes to the random pool in-place. + * + * Reserves the next |len| bytes for adding random bytes in-place + * and returns a pointer to the buffer. + * The caller is allowed to copy up to |len| bytes into the buffer. + * If |len| == 0 this is considered a no-op and a NULL pointer + * is returned without producing an error message. + * + * After updating the buffer, rand_pool_add_end() needs to be called + * to finish the udpate operation (see next comment). + */ +unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len) +{ + if (len == 0) + return NULL; + + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW); + return NULL; + } + + return pool->buffer + pool->len; +} + +/* + * Finish to add random bytes to the random pool in-place. + * + * Finishes an in-place update of the random pool started by + * rand_pool_add_begin() (see previous comment). + * It is expected that |len| bytes of random input have been added + * to the buffer which contain at least |entropy| bits of randomness. + * It is allowed to add less bytes than originally reserved. + */ +size_t rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy) +{ + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW); + return 0; + } + + if (len > 0) { + pool->len += len; + pool->entropy += entropy; + } + + return rand_pool_entropy_available(pool); } int RAND_set_rand_method(const RAND_METHOD *meth) @@ -365,15 +816,18 @@ void RAND_add(const void *buf, int num, double randomness) int RAND_priv_bytes(unsigned char *buf, int num) { const RAND_METHOD *meth = RAND_get_rand_method(); + RAND_DRBG *drbg; + int ret; if (meth != RAND_OpenSSL()) return RAND_bytes(buf, num); - if (priv_drbg.state == DRBG_UNINITIALISED - && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0) + drbg = RAND_DRBG_get0_private(); + if (drbg == NULL) return 0; - return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0); + ret = RAND_DRBG_bytes(drbg, buf, num); + return ret; } int RAND_bytes(unsigned char *buf, int num)