X-Git-Url: https://git.openssl.org/?a=blobdiff_plain;f=crypto%2Frand%2Frand_lib.c;h=1ab2a8246c4af5b636c90dd853512ac587c656d6;hb=fa3eb248e29ca8031e6a14e8a2c6f3cd58b5450e;hp=e76ca2702d908b33e1828fbe5bae40ca0d3ecefc;hpb=69a978d35984bb27af336cffc252bdde51d36adb;p=openssl.git

diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index e76ca2702d..1ab2a8246c 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -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
@@ -15,266 +15,768 @@
 #include <openssl/engine.h>
 #include "internal/thread_once.h"
 #include "rand_lcl.h"
+#include "e_os.h"
 
-#ifndef OPENSSL_NO_ENGINE
+#ifndef FIPS_MODE
+# ifndef OPENSSL_NO_ENGINE
 /* non-NULL if default_RAND_meth is ENGINE-provided */
 static ENGINE *funct_ref;
 static CRYPTO_RWLOCK *rand_engine_lock;
-#endif
+# endif
 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;
+
+static int rand_inited = 0;
+#endif /* FIPS_MODE */
+
+int rand_fork_count;
 
 #ifdef OPENSSL_RAND_SEED_RDTSC
 /*
  * IMPORTANT NOTE:  It is not currently possible to use this code
- * because we are not sure about the amount of randomness.  Some
- * SP900 tests have been run, but there is internal skepticism.
+ * because we are not sure about the amount of randomness it provides.
+ * Some SP900 tests have been run, but there is internal skepticism.
  * So for now this code is not used.
  */
 # 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_fn cb, void *arg)
+size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
 {
     unsigned char c;
     int i;
 
-    for (i = 0; i < 10; i++) {
-        c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
-        cb(arg, &c, 1, 0.5);
+    if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
+        for (i = 0; i < TSC_READ_COUNT; i++) {
+            c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
+            rand_pool_add(pool, &c, 1, 4);
+        }
     }
+    return rand_pool_entropy_available(pool);
 }
 #endif
 
 #ifdef OPENSSL_RAND_SEED_RDCPU
-size_t OPENSSL_ia32_rdseed(void);
-size_t OPENSSL_ia32_rdrand(void);
+size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
+size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
+
+/*
+ * 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)
+{
+    size_t bytes_needed;
+    unsigned char *buffer;
+
+    bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+    if (bytes_needed > 0) {
+        buffer = rand_pool_add_begin(pool, bytes_needed);
+
+        if (buffer != NULL) {
+            /* Whichever comes first, use RDSEED, RDRAND or nothing */
+            if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
+                if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
+                    == bytes_needed) {
+                    rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
+                }
+            } else if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
+                if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
+                    == bytes_needed) {
+                    rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
+                }
+            } else {
+                rand_pool_add_end(pool, 0, 0);
+            }
+        }
+    }
+
+    return rand_pool_entropy_available(pool);
+}
+#endif
 
-extern unsigned int OPENSSL_ia32cap_P[];
 
-int rand_read_cpu(RAND_poll_fn cb, void *arg)
+/*
+ * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ * 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 rand_drbg_get_entropy(RAND_DRBG *drbg,
+                             unsigned char **pout,
+                             int entropy, size_t min_len, size_t max_len,
+                             int prediction_resistance)
 {
-    size_t i, s;
+    size_t ret = 0;
+    size_t entropy_available = 0;
+    RAND_POOL *pool;
+
+    if (drbg->parent != NULL && 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;
+    }
 
-    /* If RDSEED is available, use that. */
-    if ((OPENSSL_ia32cap_P[1] & (1 << 18)) != 0) {
-        for (i = 0; i < RANDOMNESS_NEEDED; i += sizeof(s)) {
-            s = OPENSSL_ia32_rdseed();
-            if (s == 0)
-                break;
-            cb(arg, &s, (int)sizeof(s), sizeof(s));
-        }
-        if (i >= RANDOMNESS_NEEDED)
-            return 1;
+    if (drbg->seed_pool != NULL) {
+        pool = drbg->seed_pool;
+        pool->entropy_requested = entropy;
+    } else {
+        pool = rand_pool_new(entropy, drbg->secure, min_len, max_len);
+        if (pool == NULL)
+            return 0;
     }
 
-    /* Second choice is RDRAND. */
-    if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
-        for (i = 0; i < RANDOMNESS_NEEDED; i += sizeof(s)) {
-            s = OPENSSL_ia32_rdrand();
-            if (s == 0)
-                break;
-            cb(arg, &s, (int)sizeof(s), sizeof(s));
+    if (drbg->parent != NULL) {
+        size_t bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+        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,
+                                   NULL, 0) != 0)
+                bytes = bytes_needed;
+            drbg->reseed_next_counter
+                = tsan_load(&drbg->parent->reseed_prop_counter);
+            rand_drbg_unlock(drbg->parent);
+
+            rand_pool_add_end(pool, bytes, 8 * bytes);
+            entropy_available = rand_pool_entropy_available(pool);
         }
-        if (i >= RANDOMNESS_NEEDED)
-            return 1;
+
+    } else {
+        /* Get entropy by polling system entropy sources. */
+        entropy_available = rand_pool_acquire_entropy(pool);
+    }
+
+    if (entropy_available > 0) {
+        ret   = rand_pool_length(pool);
+        *pout = rand_pool_detach(pool);
     }
 
+    if (drbg->seed_pool == NULL)
+        rand_pool_free(pool);
+    return ret;
+}
+
+/*
+ * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
+ *
+ */
+void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
+                               unsigned char *out, size_t outlen)
+{
+    if (drbg->seed_pool == NULL) {
+        if (drbg->secure)
+            OPENSSL_secure_clear_free(out, outlen);
+        else
+            OPENSSL_clear_free(out, outlen);
+    }
+}
+
+/*
+ * 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(RAND_POOL *pool, unsigned char **pout)
+{
+    size_t ret = 0;
+
+    if (rand_pool_add_additional_data(pool) == 0)
+        goto err;
+
+    ret = rand_pool_length(pool);
+    *pout = rand_pool_detach(pool);
+
+ err:
+    return ret;
+}
+
+void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
+{
+    rand_pool_reattach(pool, out);
+}
+
+void rand_fork(void)
+{
+    rand_fork_count++;
+}
+
+#ifndef FIPS_MODE
+DEFINE_RUN_ONCE_STATIC(do_rand_init)
+{
+# ifndef OPENSSL_NO_ENGINE
+    rand_engine_lock = CRYPTO_THREAD_lock_new();
+    if (rand_engine_lock == NULL)
+        return 0;
+# endif
+
+    rand_meth_lock = CRYPTO_THREAD_lock_new();
+    if (rand_meth_lock == NULL)
+        goto err;
+
+    if (!rand_pool_init())
+        goto err;
+
+    rand_inited = 1;
+    return 1;
+
+ err:
+    CRYPTO_THREAD_lock_free(rand_meth_lock);
+    rand_meth_lock = NULL;
+# ifndef OPENSSL_NO_ENGINE
+    CRYPTO_THREAD_lock_free(rand_engine_lock);
+    rand_engine_lock = NULL;
+# endif
     return 0;
 }
-#endif
 
+void rand_cleanup_int(void)
+{
+    const RAND_METHOD *meth = default_RAND_meth;
+
+    if (!rand_inited)
+        return;
 
+    if (meth != NULL && meth->cleanup != NULL)
+        meth->cleanup();
+    RAND_set_rand_method(NULL);
+    rand_pool_cleanup();
+# ifndef OPENSSL_NO_ENGINE
+    CRYPTO_THREAD_lock_free(rand_engine_lock);
+    rand_engine_lock = NULL;
+# endif
+    CRYPTO_THREAD_lock_free(rand_meth_lock);
+    rand_meth_lock = NULL;
+    rand_inited = 0;
+}
+
+/* TODO(3.0): Do we need to handle this somehow in the FIPS module? */
 /*
- * 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.
+ * RAND_close_seed_files() ensures that any seed file descriptors are
+ * closed after use.
+ */
+void RAND_keep_random_devices_open(int keep)
+{
+    if (RUN_ONCE(&rand_init, do_rand_init))
+        rand_pool_keep_random_devices_open(keep);
+}
+
+/*
+ * RAND_poll() reseeds the default RNG using random input
  *
- * 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.
+ * 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.
  */
-size_t drbg_entropy_from_system(RAND_DRBG *drbg,
-                                unsigned char **pout,
-                                int entropy, size_t min_len, size_t max_len)
+int RAND_poll(void)
 {
-    int i;
+    int ret = 0;
 
+    const RAND_METHOD *meth = RAND_get_rand_method();
 
-    if (min_len > (size_t)drbg->size) {
-        /* Should not happen.  See comment near RANDOMNESS_NEEDED. */
-        min_len = drbg->size;
-    }
+    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 {
+        RAND_POOL *pool = NULL;
+
+        /* fill random pool and seed the current legacy RNG */
+        pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
+                             (RAND_DRBG_STRENGTH + 7) / 8,
+                             RAND_POOL_MAX_LENGTH);
+        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;
 
-    if (drbg->filled) {
-        /* Re-use what we have. */
-        *pout = drbg->randomness;
-        return drbg->size;
+     err:
+        rand_pool_free(pool);
     }
 
-    /* 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);
+    return ret;
+}
+#endif /* FIPS_MODE */
+
+/*
+ * Allocate memory and initialize a new random pool
+ */
+
+RAND_POOL *rand_pool_new(int entropy_requested, int secure,
+                         size_t min_len, size_t max_len)
+{
+    RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
+    size_t min_alloc_size = RAND_POOL_MIN_ALLOCATION(secure);
+
+    if (pool == NULL) {
+        RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+        return NULL;
     }
 
-    /* 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);
+    pool->min_len = min_len;
+    pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
+        RAND_POOL_MAX_LENGTH : max_len;
+    pool->alloc_len = min_len < min_alloc_size ? min_alloc_size : min_len;
+    if (pool->alloc_len > pool->max_len)
+        pool->alloc_len = pool->max_len;
+
+    if (secure)
+        pool->buffer = OPENSSL_secure_zalloc(pool->alloc_len);
+    else
+        pool->buffer = OPENSSL_zalloc(pool->alloc_len);
+
+    if (pool->buffer == NULL) {
+        RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
+        goto err;
     }
-    CRYPTO_THREAD_unlock(rand_bytes.lock);
-    *pout = drbg->randomness;
-    return min_len;
+
+    pool->entropy_requested = entropy_requested;
+    pool->secure = secure;
+
+    return pool;
+
+err:
+    OPENSSL_free(pool);
+    return NULL;
 }
 
-size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
-                                unsigned char **pout,
-                                int entropy, size_t min_len, size_t max_len)
+/*
+ * Attach new random pool to the given buffer
+ *
+ * This function is intended to be used only for feeding random data
+ * provided by RAND_add() and RAND_seed() into the <master> DRBG.
+ */
+RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
+                            size_t entropy)
 {
-    int st;
+    RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
 
-    if (min_len > (size_t)drbg->size) {
-        /* Should not happen.  See comment near RANDOMNESS_NEEDED. */
-        min_len = drbg->size;
+    if (pool == NULL) {
+        RANDerr(RAND_F_RAND_POOL_ATTACH, ERR_R_MALLOC_FAILURE);
+        return NULL;
     }
 
-    /* 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)
-        return 0;
-    drbg->filled = 1;
-    *pout = drbg->randomness;
-    return min_len;
+    /*
+     * The const needs to be cast away, but attached buffers will not be
+     * modified (in contrary to allocated buffers which are zeroed and
+     * freed in the end).
+     */
+    pool->buffer = (unsigned char *) buffer;
+    pool->len = len;
+
+    pool->attached = 1;
+
+    pool->min_len = pool->max_len = pool->alloc_len = pool->len;
+    pool->entropy = entropy;
+
+    return pool;
+}
+
+/*
+ * Free |pool|, securely erasing its buffer.
+ */
+void rand_pool_free(RAND_POOL *pool)
+{
+    if (pool == NULL)
+        return;
+
+    /*
+     * Although it would be advisable from a cryptographical viewpoint,
+     * we are not allowed to clear attached buffers, since they are passed
+     * to rand_pool_attach() as `const unsigned char*`.
+     * (see corresponding comment in rand_pool_attach()).
+     */
+    if (!pool->attached) {
+        if (pool->secure)
+            OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
+        else
+            OPENSSL_clear_free(pool->buffer, pool->alloc_len);
+    }
+
+    OPENSSL_free(pool);
 }
 
-void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out)
+/*
+ * Return the |pool|'s buffer to the caller (readonly).
+ */
+const unsigned char *rand_pool_buffer(RAND_POOL *pool)
 {
-    drbg->filled = 0;
-    OPENSSL_cleanse(drbg->randomness, drbg->size);
+    return pool->buffer;
 }
 
+/*
+ * Return the |pool|'s entropy to the caller.
+ */
+size_t rand_pool_entropy(RAND_POOL *pool)
+{
+    return pool->entropy;
+}
 
 /*
- * Set up a global DRBG.
+ * Return the |pool|'s buffer length to the caller.
  */
-static int setup_drbg(RAND_DRBG *drbg)
-{
-    int ret = 1;
-
-    drbg->lock = CRYPTO_THREAD_lock_new();
-    ret &= drbg->lock != NULL;
-    drbg->size = RANDOMNESS_NEEDED;
-    drbg->randomness = OPENSSL_malloc(drbg->size);
-    ret &= 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;
+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() or to re-attach it
+ * again to the pool using rand_pool_reattach().
+ */
+unsigned char *rand_pool_detach(RAND_POOL *pool)
+{
+    unsigned char *ret = pool->buffer;
+    pool->buffer = NULL;
+    pool->entropy = 0;
     return ret;
 }
 
-static void free_drbg(RAND_DRBG *drbg)
+/*
+ * Re-attach the |pool| buffer. It is only allowed to pass
+ * the |buffer| which was previously detached from the same pool.
+ */
+void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer)
 {
-    CRYPTO_THREAD_lock_free(drbg->lock);
-    OPENSSL_clear_free(drbg->randomness, drbg->size);
-    RAND_DRBG_uninstantiate(drbg);
+    pool->buffer = buffer;
+    OPENSSL_cleanse(pool->buffer, pool->len);
+    pool->len = 0;
 }
 
-DEFINE_RUN_ONCE_STATIC(do_rand_init)
+/*
+ * If |entropy_factor| bits contain 1 bit of entropy, how many bytes does one
+ * need to obtain at least |bits| bits of entropy?
+ */
+#define ENTROPY_TO_BYTES(bits, entropy_factor) \
+    (((bits) * (entropy_factor) + 7) / 8)
+
+
+/*
+ * 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)
 {
-    int ret = 1;
+    if (pool->entropy < pool->entropy_requested)
+        return 0;
 
-#ifndef OPENSSL_NO_ENGINE
-    rand_engine_lock = CRYPTO_THREAD_lock_new();
-    ret &= rand_engine_lock != NULL;
-#endif
-    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;
-    /* TODO: Should this be secure malloc? */
-    rand_bytes.buff = malloc(rand_bytes.size);
-
-    ret &= rand_bytes.buff != NULL;
-    ret &= setup_drbg(&rand_drbg);
-    ret &= setup_drbg(&priv_drbg);
-    return ret;
+    if (pool->len < pool->min_len)
+        return 0;
+
+    return pool->entropy;
 }
 
+/*
+ * Returns the (remaining) amount of entropy needed to fill
+ * the random pool.
+ */
 
-void rand_cleanup_int(void)
+size_t rand_pool_entropy_needed(RAND_POOL *pool)
 {
-    const RAND_METHOD *meth = default_RAND_meth;
+    if (pool->entropy < pool->entropy_requested)
+        return pool->entropy_requested - pool->entropy;
 
-    if (meth != NULL && meth->cleanup != NULL)
-        meth->cleanup();
-    RAND_set_rand_method(NULL);
-#ifndef OPENSSL_NO_ENGINE
-    CRYPTO_THREAD_lock_free(rand_engine_lock);
-#endif
-    CRYPTO_THREAD_lock_free(rand_meth_lock);
-    CRYPTO_THREAD_lock_free(rand_bytes.lock);
-    OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
-    free_drbg(&rand_drbg);
-    free_drbg(&priv_drbg);
+    return 0;
+}
+
+/* Increase the allocation size -- not usable for an attached pool */
+static int rand_pool_grow(RAND_POOL *pool, size_t len)
+{
+    if (len > pool->alloc_len - pool->len) {
+        unsigned char *p;
+        const size_t limit = pool->max_len / 2;
+        size_t newlen = pool->alloc_len;
+
+        if (pool->attached || len > pool->max_len - pool->len) {
+            RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+
+        do
+            newlen = newlen < limit ? newlen * 2 : pool->max_len;
+        while (len > newlen - pool->len);
+
+        if (pool->secure)
+            p = OPENSSL_secure_zalloc(newlen);
+        else
+            p = OPENSSL_zalloc(newlen);
+        if (p == NULL) {
+            RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_MALLOC_FAILURE);
+            return 0;
+        }
+        memcpy(p, pool->buffer, pool->len);
+        if (pool->secure)
+            OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
+        else
+            OPENSSL_clear_free(pool->buffer, pool->alloc_len);
+        pool->buffer = p;
+        pool->alloc_len = newlen;
+    }
+    return 1;
 }
 
 /*
- * 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().
+ * Returns the number of bytes needed to fill the pool, assuming
+ * the input has 1 / |entropy_factor| entropy bits per data bit.
+ * In case of an error, 0 is returned.
  */
-static void call_rand_add(void* arg, const void *buf, int num, double r)
+
+size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
 {
-    RAND_add(buf, num, r);
+    size_t bytes_needed;
+    size_t entropy_needed = rand_pool_entropy_needed(pool);
+
+    if (entropy_factor < 1) {
+        RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
+        return 0;
+    }
+
+    bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_factor);
+
+    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;
+
+    /*
+     * Make sure the buffer is large enough for the requested amount
+     * of data. This guarantees that existing code patterns where
+     * rand_pool_add_begin, rand_pool_add_end or rand_pool_add
+     * are used to collect entropy data without any error handling
+     * whatsoever, continue to be valid.
+     * Furthermore if the allocation here fails once, make sure that
+     * we don't fall back to a less secure or even blocking random source,
+     * as that could happen by the existing code patterns.
+     * This is not a concern for additional data, therefore that
+     * is not needed if rand_pool_grow fails in other places.
+     */
+    if (!rand_pool_grow(pool, bytes_needed)) {
+        /* persistent error for this pool */
+        pool->max_len = pool->len = 0;
+        return 0;
+    }
+
+    return bytes_needed;
 }
 
-int RAND_poll(void)
+/* 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.
+ *
+ * Returns 1 if the added amount is adequate, otherwise 0
+ */
+int rand_pool_add(RAND_POOL *pool,
+                  const unsigned char *buffer, size_t len, size_t entropy)
 {
-    return RAND_poll_ex(call_rand_add, NULL);
+    if (len > pool->max_len - pool->len) {
+        RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
+        return 0;
+    }
+
+    if (pool->buffer == NULL) {
+        RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    if (len > 0) {
+        /*
+         * This is to protect us from accidentally passing the buffer
+         * returned from rand_pool_add_begin.
+         * The check for alloc_len makes sure we do not compare the
+         * address of the end of the allocated memory to something
+         * different, since that comparison would have an
+         * indeterminate result.
+         */
+        if (pool->alloc_len > pool->len && pool->buffer + pool->len == buffer) {
+            RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+        /*
+         * We have that only for cases when a pool is used to collect
+         * additional data.
+         * For entropy data, as long as the allocation request stays within
+         * the limits given by rand_pool_bytes_needed this rand_pool_grow
+         * below is guaranteed to succeed, thus no allocation happens.
+         */
+        if (!rand_pool_grow(pool, len))
+            return 0;
+        memcpy(pool->buffer + pool->len, buffer, len);
+        pool->len += len;
+        pool->entropy += entropy;
+    }
+
+    return 1;
+}
+
+/*
+ * 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;
+    }
+
+    if (pool->buffer == NULL) {
+        RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, ERR_R_INTERNAL_ERROR);
+        return NULL;
+    }
+
+    /*
+     * As long as the allocation request stays within the limits given
+     * by rand_pool_bytes_needed this rand_pool_grow below is guaranteed
+     * to succeed, thus no allocation happens.
+     * We have that only for cases when a pool is used to collect
+     * additional data. Then the buffer might need to grow here,
+     * and of course the caller is responsible to check the return
+     * value of this function.
+     */
+    if (!rand_pool_grow(pool, len))
+        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.
+ */
+int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy)
+{
+    if (len > pool->alloc_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 1;
 }
 
+#ifndef FIPS_MODE
 int RAND_set_rand_method(const RAND_METHOD *meth)
 {
     if (!RUN_ONCE(&rand_init, do_rand_init))
         return 0;
 
     CRYPTO_THREAD_write_lock(rand_meth_lock);
-#ifndef OPENSSL_NO_ENGINE
+# ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(funct_ref);
     funct_ref = NULL;
-#endif
+# endif
     default_RAND_meth = meth;
     CRYPTO_THREAD_unlock(rand_meth_lock);
     return 1;
 }
+#endif
 
 const RAND_METHOD *RAND_get_rand_method(void)
 {
+#ifdef FIPS_MODE
+    return NULL;
+#else
     const RAND_METHOD *tmp_meth = NULL;
 
     if (!RUN_ONCE(&rand_init, do_rand_init))
@@ -282,7 +784,7 @@ const RAND_METHOD *RAND_get_rand_method(void)
 
     CRYPTO_THREAD_write_lock(rand_meth_lock);
     if (default_RAND_meth == NULL) {
-#ifndef OPENSSL_NO_ENGINE
+# ifndef OPENSSL_NO_ENGINE
         ENGINE *e;
 
         /* If we have an engine that can do RAND, use it. */
@@ -294,16 +796,17 @@ const RAND_METHOD *RAND_get_rand_method(void)
             ENGINE_finish(e);
             default_RAND_meth = &rand_meth;
         }
-#else
+# else
         default_RAND_meth = &rand_meth;
-#endif
+# endif
     }
     tmp_meth = default_RAND_meth;
     CRYPTO_THREAD_unlock(rand_meth_lock);
     return tmp_meth;
+#endif
 }
 
-#ifndef OPENSSL_NO_ENGINE
+#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
 int RAND_set_rand_engine(ENGINE *engine)
 {
     const RAND_METHOD *tmp_meth = NULL;
@@ -350,31 +853,55 @@ void RAND_add(const void *buf, int num, double randomness)
  * the default method, then just call RAND_bytes().  Otherwise make
  * sure we're instantiated and use the private DRBG.
  */
-int RAND_priv_bytes(unsigned char *buf, int num)
+int rand_priv_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
 {
+    RAND_DRBG *drbg;
+    int ret;
     const RAND_METHOD *meth = RAND_get_rand_method();
 
     if (meth != RAND_OpenSSL())
-        return RAND_bytes(buf, num);
+        return meth->bytes(buf, num);
 
-    if (priv_drbg.state == DRBG_UNINITIALISED
-            && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)
+    drbg = OPENSSL_CTX_get0_private_drbg(ctx);
+    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)
+int RAND_priv_bytes(unsigned char *buf, int num)
+{
+    return rand_priv_bytes_ex(NULL, buf, num);
+}
+
+int rand_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
 {
+    RAND_DRBG *drbg;
+    int ret;
     const RAND_METHOD *meth = RAND_get_rand_method();
 
-    if (meth->bytes != NULL)
-        return meth->bytes(buf, num);
-    RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
-    return -1;
+    if (meth != RAND_OpenSSL()) {
+        if (meth->bytes != NULL)
+            return meth->bytes(buf, num);
+        RANDerr(RAND_F_RAND_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
+        return -1;
+    }
+
+    drbg = OPENSSL_CTX_get0_public_drbg(ctx);
+    if (drbg == NULL)
+        return 0;
+
+    ret = RAND_DRBG_bytes(drbg, buf, num);
+    return ret;
+}
+
+int RAND_bytes(unsigned char *buf, int num)
+{
+    return rand_bytes_ex(NULL, buf, num);
 }
 
-#if OPENSSL_API_COMPAT < 0x10100000L
+#if !OPENSSL_API_1_1_0 && !defined(FIPS_MODE)
 int RAND_pseudo_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();