Fix error handling in RAND_DRBG_set
[openssl.git] / crypto / rand / drbg_lib.c
index 4404e4f..f518ce5 100644 (file)
 #include "rand_lcl.h"
 #include "internal/thread_once.h"
 #include "internal/rand_int.h"
+#include "internal/cryptlib_int.h"
 
 /*
- * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
- * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
+ * Support framework for NIST SP 800-90A DRBG
+ *
+ * See manual page RAND_DRBG(7) for a general overview.
  *
  * The OpenSSL model is to have new and free functions, and that new
  * does all initialization.  That is not the NIST model, which has
  */
 
 /*
- * THE THREE SHARED DRBGs
- *
- * There are three shared DRBGs (master, public and private), which are
- * accessed concurrently by all threads.
+ * The three shared DRBG instances
  *
- * THE MASTER DRBG
+ * There are three shared DRBG instances: <master>, <public>, and <private>.
+ */
+
+/*
+ * The <master> DRBG
  *
  * Not used directly by the application, only for reseeding the two other
  * DRBGs. It reseeds itself by pulling either randomness from os entropy
- * sources or by consuming randomnes which was added by RAND_add()
+ * sources or by consuming randomness which was added by RAND_add().
+ *
+ * The <master> DRBG is a global instance which is accessed concurrently by
+ * all threads. The necessary locking is managed automatically by its child
+ * DRBG instances during reseeding.
  */
-static RAND_DRBG *drbg_master;
+static RAND_DRBG *master_drbg;
 /*
- * THE PUBLIC DRBG
+ * The <public> DRBG
  *
  * Used by default for generating random bytes using RAND_bytes().
+ *
+ * The <public> DRBG is thread-local, i.e., there is one instance per thread.
  */
-static RAND_DRBG *drbg_public;
+static CRYPTO_THREAD_LOCAL public_drbg;
 /*
- * THE PRIVATE DRBG
+ * The <private> DRBG
  *
  * Used by default for generating private keys using RAND_priv_bytes()
- */
-static RAND_DRBG *drbg_private;
-/*+
- * DRBG HIERARCHY
- *
- * In addition there are DRBGs, which are not shared, but used only by a
- * single thread at every time, for example the DRBGs which are owned by
- * an SSL context. All DRBGs are organized in a hierarchical fashion
- * with the <master> DRBG as root.
  *
- * This gives the following overall picture:
- *
- *                  <os entropy sources>
- *                         |
- *    RAND_add() ==>    <master>          \
- *                       /   \            | shared DRBGs (with locking)
- *                 <public>  <private>    /
- *                     |
- *                   <ssl>  owned by an SSL context
- *
- * AUTOMATIC RESEEDING
- *
- * Before satisfying a generate request, a DRBG reseeds itself automatically,
- * if one of the following two conditions holds:
- *
- * - the number of generate requests since the last reseeding exceeds a
- *   certain threshold, the so called |reseed_interval|. This behaviour
- *   can be disabled by setting the |reseed_interval| to 0.
- *
- * - the time elapsed since the last reseeding exceeds a certain time
- *   interval, the so called |reseed_time_interval|. This behaviour
- *   can be disabled by setting the |reseed_time_interval| to 0.
- *
- * MANUAL RESEEDING
- *
- * For the three shared DRBGs (and only for these) there is another way to
- * reseed them manually by calling RAND_seed() (or RAND_add() with a positive
- * |randomness| argument). This will immediately reseed the <master> DRBG.
- * The <public> and <private> DRBG will detect this on their next generate
- * call and reseed, pulling randomness from <master>.
+ * The <private> DRBG is thread-local, i.e., there is one instance per thread.
  */
+static CRYPTO_THREAD_LOCAL private_drbg;
+
 
 
 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
@@ -98,72 +71,248 @@ static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
 
 static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
 
-static RAND_DRBG *drbg_setup(RAND_DRBG *parent);
-static void drbg_cleanup(RAND_DRBG *drbg);
+
+#define RAND_DRBG_TYPE_FLAGS    ( \
+    RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
+
+#define RAND_DRBG_TYPE_MASTER                     0
+#define RAND_DRBG_TYPE_PUBLIC                     1
+#define RAND_DRBG_TYPE_PRIVATE                    2
+
+/* Defaults */
+static int rand_drbg_type[3] = {
+    RAND_DRBG_TYPE, /* Master */
+    RAND_DRBG_TYPE, /* Public */
+    RAND_DRBG_TYPE  /* Private */
+};
+static unsigned int rand_drbg_flags[3] = {
+    RAND_DRBG_FLAGS | RAND_DRBG_FLAG_MASTER, /* Master */
+    RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PUBLIC, /* Public */
+    RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PRIVATE /* Private */
+};
+
+static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
+static unsigned int slave_reseed_interval  = SLAVE_RESEED_INTERVAL;
+
+static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
+static time_t slave_reseed_time_interval  = SLAVE_RESEED_TIME_INTERVAL;
+
+/* A logical OR of all used DRBG flag bits (currently there is only one) */
+static const unsigned int rand_drbg_used_flags =
+    RAND_DRBG_FLAG_CTR_NO_DF | RAND_DRBG_FLAG_HMAC | RAND_DRBG_TYPE_FLAGS;
+
+
+static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type);
+
+static RAND_DRBG *rand_drbg_new(int secure,
+                                int type,
+                                unsigned int flags,
+                                RAND_DRBG *parent);
+
+static int is_ctr(int type)
+{
+    switch (type) {
+    case NID_aes_128_ctr:
+    case NID_aes_192_ctr:
+    case NID_aes_256_ctr:
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+static int is_digest(int type)
+{
+    switch (type) {
+    case NID_sha1:
+    case NID_sha224:
+    case NID_sha256:
+    case NID_sha384:
+    case NID_sha512:
+    case NID_sha512_224:
+    case NID_sha512_256:
+    case NID_sha3_224:
+    case NID_sha3_256:
+    case NID_sha3_384:
+    case NID_sha3_512:
+        return 1;
+    default:
+        return 0;
+    }
+}
 
 /*
- * Set/initialize |drbg| to be of type |nid|, with optional |flags|.
+ * Set/initialize |drbg| to be of type |type|, with optional |flags|.
+ *
+ * If |type| and |flags| are zero, use the defaults
  *
  * Returns 1 on success, 0 on failure.
  */
-int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
+int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
 {
     int ret = 1;
 
+    if (type == 0 && flags == 0) {
+        type = rand_drbg_type[RAND_DRBG_TYPE_MASTER];
+        flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER];
+    }
+
+    /* If set is called multiple times - clear the old one */
+    if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
+        drbg->meth->uninstantiate(drbg);
+        rand_pool_free(drbg->adin_pool);
+        drbg->adin_pool = NULL;
+    }
+
     drbg->state = DRBG_UNINITIALISED;
     drbg->flags = flags;
-    drbg->nid = nid;
+    drbg->type = type;
 
-    switch (nid) {
-    default:
-        RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
-        return 0;
-    case 0:
+    if (type == 0) {
         /* Uninitialized; that's okay. */
+        drbg->meth = NULL;
         return 1;
-    case NID_aes_128_ctr:
-    case NID_aes_192_ctr:
-    case NID_aes_256_ctr:
+    } else if (is_ctr(type)) {
         ret = drbg_ctr_init(drbg);
-        break;
+    } else if (is_digest(type)) {
+        if (flags & RAND_DRBG_FLAG_HMAC)
+            ret = drbg_hmac_init(drbg);
+        else
+            ret = drbg_hash_init(drbg);
+    } else {
+        drbg->type = 0;
+        drbg->flags = 0;
+        drbg->meth = NULL;
+        RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
+        return 0;
     }
 
-    if (ret == 0)
+    if (ret == 0) {
+        drbg->state = DRBG_ERROR;
         RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
+    }
     return ret;
 }
 
 /*
- * Allocate memory and initialize a new DRBG.  The |parent|, if not
- * NULL, will be used to auto-seed this RAND_DRBG as needed.
+ * Set/initialize default |type| and |flag| for new drbg instances.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int RAND_DRBG_set_defaults(int type, unsigned int flags)
+{
+    int all;
+    if (!(is_digest(type) || is_ctr(type))) {
+        RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
+        return 0;
+    }
+
+    if ((flags & ~rand_drbg_used_flags) != 0) {
+        RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
+        return 0;
+    }
+
+    all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
+    if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
+        rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
+        rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
+    }
+    if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
+        rand_drbg_type[RAND_DRBG_TYPE_PUBLIC]  = type;
+        rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
+    }
+    if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
+        rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
+        rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
+    }
+    return 1;
+}
+
+
+/*
+ * Allocate memory and initialize a new DRBG. The DRBG is allocated on
+ * the secure heap if |secure| is nonzero and the secure heap is enabled.
+ * The |parent|, if not NULL, will be used as random source for reseeding.
  *
  * Returns a pointer to the new DRBG instance on success, NULL on failure.
  */
-RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
+static RAND_DRBG *rand_drbg_new(int secure,
+                                int type,
+                                unsigned int flags,
+                                RAND_DRBG *parent)
 {
-    RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
+    RAND_DRBG *drbg = secure ?
+        OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg));
 
     if (drbg == NULL) {
         RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
-        goto err;
+        return NULL;
     }
+
+    drbg->secure = secure && CRYPTO_secure_allocated(drbg);
     drbg->fork_count = rand_fork_count;
     drbg->parent = parent;
+
+    if (parent == NULL) {
+        drbg->get_entropy = rand_drbg_get_entropy;
+        drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
+#ifndef RAND_DRBG_GET_RANDOM_NONCE
+        drbg->get_nonce = rand_drbg_get_nonce;
+        drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
+#endif
+
+        drbg->reseed_interval = master_reseed_interval;
+        drbg->reseed_time_interval = master_reseed_time_interval;
+    } else {
+        drbg->get_entropy = rand_drbg_get_entropy;
+        drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
+        /*
+         * Do not provide nonce callbacks, the child DRBGs will
+         * obtain their nonce using random bits from the parent.
+         */
+
+        drbg->reseed_interval = slave_reseed_interval;
+        drbg->reseed_time_interval = slave_reseed_time_interval;
+    }
+
     if (RAND_DRBG_set(drbg, type, flags) == 0)
         goto err;
 
-    if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
-                                 rand_drbg_cleanup_entropy,
-                                 NULL, NULL))
-        goto err;
+    if (parent != NULL) {
+        rand_drbg_lock(parent);
+        if (drbg->strength > parent->strength) {
+            /*
+             * We currently don't support the algorithm from NIST SP 800-90C
+             * 10.1.2 to use a weaker DRBG as source
+             */
+            rand_drbg_unlock(parent);
+            RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
+            goto err;
+        }
+        rand_drbg_unlock(parent);
+    }
 
     return drbg;
 
-err:
-    OPENSSL_free(drbg);
+ err:
+    if (drbg->secure)
+        OPENSSL_secure_free(drbg);
+    else
+        OPENSSL_free(drbg);
+
     return NULL;
 }
 
+RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
+{
+    return rand_drbg_new(0, type, flags, parent);
+}
+
+RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
+{
+    return rand_drbg_new(1, type, flags, parent);
+}
+
 /*
  * Uninstantiate |drbg| and free all memory.
  */
@@ -174,8 +323,14 @@ void RAND_DRBG_free(RAND_DRBG *drbg)
 
     if (drbg->meth != NULL)
         drbg->meth->uninstantiate(drbg);
+    rand_pool_free(drbg->adin_pool);
+    CRYPTO_THREAD_lock_free(drbg->lock);
     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
-    OPENSSL_clear_free(drbg, sizeof(*drbg));
+
+    if (drbg->secure)
+        OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
+    else
+        OPENSSL_clear_free(drbg, sizeof(*drbg));
 }
 
 /*
@@ -191,6 +346,9 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
 {
     unsigned char *nonce = NULL, *entropy = NULL;
     size_t noncelen = 0, entropylen = 0;
+    size_t min_entropy = drbg->strength;
+    size_t min_entropylen = drbg->min_entropylen;
+    size_t max_entropylen = drbg->max_entropylen;
 
     if (perslen > drbg->max_perslen) {
         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
@@ -198,8 +356,7 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
         goto end;
     }
 
-    if (drbg->meth == NULL)
-    {
+    if (drbg->meth == NULL) {
         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
                 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
         goto end;
@@ -213,21 +370,40 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
     }
 
     drbg->state = DRBG_ERROR;
+
+    /*
+     * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
+     * and nonce in 1 call by increasing the entropy with 50% and increasing
+     * the minimum length to accomadate the length of the nonce.
+     * We do this in case a nonce is require and get_nonce is NULL.
+     */
+    if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
+        min_entropy += drbg->strength / 2;
+        min_entropylen += drbg->min_noncelen;
+        max_entropylen += drbg->max_noncelen;
+    }
+
+    drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
+    if (drbg->reseed_next_counter) {
+        drbg->reseed_next_counter++;
+        if(!drbg->reseed_next_counter)
+            drbg->reseed_next_counter = 1;
+    }
+
     if (drbg->get_entropy != NULL)
-        entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
-                                   drbg->min_entropylen, drbg->max_entropylen);
-    if (entropylen < drbg->min_entropylen
-        || entropylen > drbg->max_entropylen) {
+        entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
+                                       min_entropylen, max_entropylen, 0);
+    if (entropylen < min_entropylen
+            || entropylen > max_entropylen) {
         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
         goto end;
     }
 
-    if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
+    if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
         noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
                                    drbg->min_noncelen, drbg->max_noncelen);
         if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
-            RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
-                    RAND_R_ERROR_RETRIEVING_NONCE);
+            RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
             goto end;
         }
     }
@@ -239,29 +415,15 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
     }
 
     drbg->state = DRBG_READY;
-    drbg->generate_counter = 0;
+    drbg->reseed_gen_counter = 1;
     drbg->reseed_time = time(NULL);
-    if (drbg->reseed_counter > 0) {
-        if (drbg->parent == NULL)
-            drbg->reseed_counter++;
-        else
-            drbg->reseed_counter = drbg->parent->reseed_counter;
-    }
+    tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
 
-end:
+ end:
     if (entropy != NULL && drbg->cleanup_entropy != NULL)
         drbg->cleanup_entropy(drbg, entropy, entropylen);
-    if (nonce != NULL && drbg->cleanup_nonce!= NULL )
+    if (nonce != NULL && drbg->cleanup_nonce != NULL)
         drbg->cleanup_nonce(drbg, nonce, noncelen);
-    if (drbg->pool != NULL) {
-        if (drbg->state == DRBG_READY) {
-            RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
-                    RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
-            drbg->state = DRBG_ERROR;
-        }
-        RAND_POOL_free(drbg->pool);
-        drbg->pool = NULL;
-    }
     if (drbg->state == DRBG_READY)
         return 1;
     return 0;
@@ -276,8 +438,8 @@ end:
  */
 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
 {
-    if (drbg->meth == NULL)
-    {
+    int index = -1, type, flags;
+    if (drbg->meth == NULL) {
         RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
                 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
         return 0;
@@ -288,7 +450,23 @@ int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
      * initial values.
      */
     drbg->meth->uninstantiate(drbg);
-    return RAND_DRBG_set(drbg, drbg->nid, drbg->flags);
+
+    /* The reset uses the default values for type and flags */
+    if (drbg->flags & RAND_DRBG_FLAG_MASTER)
+        index = RAND_DRBG_TYPE_MASTER;
+    else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
+        index = RAND_DRBG_TYPE_PRIVATE;
+    else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
+        index = RAND_DRBG_TYPE_PUBLIC;
+
+    if (index != -1) {
+        flags = rand_drbg_flags[index];
+        type = rand_drbg_type[index];
+    } else {
+        flags = drbg->flags;
+        type = drbg->type;
+    }
+    return RAND_DRBG_set(drbg, type, flags);
 }
 
 /*
@@ -299,7 +477,8 @@ int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
  * Returns 1 on success, 0 on failure.
  */
 int RAND_DRBG_reseed(RAND_DRBG *drbg,
-                     const unsigned char *adin, size_t adinlen)
+                     const unsigned char *adin, size_t adinlen,
+                     int prediction_resistance)
 {
     unsigned char *entropy = NULL;
     size_t entropylen = 0;
@@ -313,19 +492,29 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
         return 0;
     }
 
-    if (adin == NULL)
+    if (adin == NULL) {
         adinlen = 0;
-    else if (adinlen > drbg->max_adinlen) {
+    else if (adinlen > drbg->max_adinlen) {
         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
         return 0;
     }
 
     drbg->state = DRBG_ERROR;
+
+    drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
+    if (drbg->reseed_next_counter) {
+        drbg->reseed_next_counter++;
+        if(!drbg->reseed_next_counter)
+            drbg->reseed_next_counter = 1;
+    }
+
     if (drbg->get_entropy != NULL)
         entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
-                                   drbg->min_entropylen, drbg->max_entropylen);
+                                       drbg->min_entropylen,
+                                       drbg->max_entropylen,
+                                       prediction_resistance);
     if (entropylen < drbg->min_entropylen
-        || entropylen > drbg->max_entropylen) {
+            || entropylen > drbg->max_entropylen) {
         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
         goto end;
     }
@@ -334,16 +523,11 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
         goto end;
 
     drbg->state = DRBG_READY;
-    drbg->generate_counter = 0;
+    drbg->reseed_gen_counter = 1;
     drbg->reseed_time = time(NULL);
-    if (drbg->reseed_counter > 0) {
-        if (drbg->parent == NULL)
-            drbg->reseed_counter++;
-        else
-            drbg->reseed_counter = drbg->parent->reseed_counter;
-    }
+    tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
 
-end:
+ end:
     if (entropy != NULL && drbg->cleanup_entropy != NULL)
         drbg->cleanup_entropy(drbg, entropy, entropylen);
     if (drbg->state == DRBG_READY)
@@ -377,8 +561,10 @@ int rand_drbg_restart(RAND_DRBG *drbg,
 
     if (drbg->pool != NULL) {
         RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
-        RAND_POOL_free(drbg->pool);
+        drbg->state = DRBG_ERROR;
+        rand_pool_free(drbg->pool);
         drbg->pool = NULL;
+        return 0;
     }
 
     if (buffer != NULL) {
@@ -386,24 +572,25 @@ int rand_drbg_restart(RAND_DRBG *drbg,
             if (drbg->max_entropylen < len) {
                 RANDerr(RAND_F_RAND_DRBG_RESTART,
                     RAND_R_ENTROPY_INPUT_TOO_LONG);
+                drbg->state = DRBG_ERROR;
                 return 0;
             }
 
             if (entropy > 8 * len) {
                 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
+                drbg->state = DRBG_ERROR;
                 return 0;
             }
 
             /* will be picked up by the rand_drbg_get_entropy() callback */
-            drbg->pool = RAND_POOL_new(entropy, len, len);
+            drbg->pool = rand_pool_attach(buffer, len, entropy);
             if (drbg->pool == NULL)
                 return 0;
-
-            RAND_POOL_add(drbg->pool, buffer, len, entropy);
         } else {
             if (drbg->max_adinlen < len) {
                 RANDerr(RAND_F_RAND_DRBG_RESTART,
                         RAND_R_ADDITIONAL_INPUT_TOO_LONG);
+                drbg->state = DRBG_ERROR;
                 return 0;
             }
             adin = buffer;
@@ -439,18 +626,12 @@ int rand_drbg_restart(RAND_DRBG *drbg,
             drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
         } else if (reseeded == 0) {
             /* do a full reseeding if it has not been done yet above */
-            RAND_DRBG_reseed(drbg, NULL, 0);
+            RAND_DRBG_reseed(drbg, NULL, 0, 0);
         }
     }
 
-    /* check whether a given entropy pool was cleared properly during reseed */
-    if (drbg->pool != NULL) {
-        drbg->state = DRBG_ERROR;
-        RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
-        RAND_POOL_free(drbg->pool);
-        drbg->pool = NULL;
-        return 0;
-    }
+    rand_pool_free(drbg->pool);
+    drbg->pool = NULL;
 
     return drbg->state == DRBG_READY;
 }
@@ -500,7 +681,7 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
     }
 
     if (drbg->reseed_interval > 0) {
-        if (drbg->generate_counter >= drbg->reseed_interval)
+        if (drbg->reseed_gen_counter > drbg->reseed_interval)
             reseed_required = 1;
     }
     if (drbg->reseed_time_interval > 0) {
@@ -509,13 +690,16 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
             || now - drbg->reseed_time >= drbg->reseed_time_interval)
             reseed_required = 1;
     }
-    if (drbg->reseed_counter > 0 && drbg->parent != NULL) {
-        if (drbg->reseed_counter != drbg->parent->reseed_counter)
+    if (drbg->parent != NULL) {
+        unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
+        if (reseed_counter > 0
+                && tsan_load(&drbg->parent->reseed_prop_counter)
+                   != reseed_counter)
             reseed_required = 1;
     }
 
     if (reseed_required || prediction_resistance) {
-        if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
+        if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
             RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
             return 0;
         }
@@ -529,7 +713,7 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
         return 0;
     }
 
-    drbg->generate_counter++;
+    drbg->reseed_gen_counter++;
 
     return 1;
 }
@@ -547,9 +731,18 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
     unsigned char *additional = NULL;
     size_t additional_len;
     size_t chunk;
-    size_t ret;
+    size_t ret = 0;
 
-    additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
+    if (drbg->adin_pool == NULL) {
+        if (drbg->type == 0)
+            goto err;
+        drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
+        if (drbg->adin_pool == NULL)
+            goto err;
+    }
+
+    additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
+                                                   &additional);
 
     for ( ; outlen > 0; outlen -= chunk, out += chunk) {
         chunk = outlen;
@@ -561,9 +754,9 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
     }
     ret = 1;
 
-err:
-    if (additional_len != 0)
-        OPENSSL_secure_clear_free(additional, additional_len);
+ err:
+    if (additional != NULL)
+        rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
 
     return ret;
 }
@@ -571,40 +764,10 @@ err:
 /*
  * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
  *
- * In the following, the signature and the semantics of the
- * get_entropy() and cleanup_entropy() callbacks are explained.
- *
- * GET_ENTROPY
- *
- *     size_t get_entropy(RAND_DRBG *ctx,
- *                        unsigned char **pout,
- *                        int entropy,
- *                        size_t min_len, size_t max_len);
- *
- * This is a request to allocate and fill a buffer of size
- * |min_len| <= size <= |max_len| (in bytes) which contains
- * at least |entropy| bits of randomness. The buffer's address is
- * to be returned in |*pout| and the number of collected
- * randomness bytes (which may be less than the allocated size
- * of the buffer) as return value.
- *
- * If the callback fails to acquire at least |entropy| bits of
- * randomness, it shall return a buffer length of 0.
- *
- * CLEANUP_ENTROPY
- *
- *     void cleanup_entropy(RAND_DRBG *ctx,
- *                          unsigned char *out, size_t outlen);
+ * Setting the callbacks is allowed only if the drbg has not been
+ * initialized yet. Otherwise, the operation will fail.
  *
- * A request to clear and free the buffer allocated by get_entropy().
- * The values |out| and |outlen| are expected to be the random buffer's
- * address and length, as returned by the get_entropy() callback.
- *
- * GET_NONCE, CLEANUP_NONCE
- *
- * Signature and semantics of the get_nonce() and cleanup_nonce()
- * callbacks are analogous to get_entropy() and cleanup_entropy().
- * Currently, the nonce is used only for the known answer tests.
+ * Returns 1 on success, 0 on failure.
  */
 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
                             RAND_DRBG_get_entropy_fn get_entropy,
@@ -612,7 +775,8 @@ int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
                             RAND_DRBG_get_nonce_fn get_nonce,
                             RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
 {
-    if (drbg->state != DRBG_UNINITIALISED)
+    if (drbg->state != DRBG_UNINITIALISED
+            || drbg->parent != NULL)
         return 0;
     drbg->get_entropy = get_entropy;
     drbg->cleanup_entropy = cleanup_entropy;
@@ -656,6 +820,101 @@ int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
     return 1;
 }
 
+/*
+ * Set the default values for reseed (time) intervals of new DRBG instances
+ *
+ * The default values can be set independently for master DRBG instances
+ * (without a parent) and slave DRBG instances (with parent).
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+
+int RAND_DRBG_set_reseed_defaults(
+                                  unsigned int _master_reseed_interval,
+                                  unsigned int _slave_reseed_interval,
+                                  time_t _master_reseed_time_interval,
+                                  time_t _slave_reseed_time_interval
+                                  )
+{
+    if (_master_reseed_interval > MAX_RESEED_INTERVAL
+        || _slave_reseed_interval > MAX_RESEED_INTERVAL)
+        return 0;
+
+    if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
+        || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
+        return 0;
+
+    master_reseed_interval = _master_reseed_interval;
+    slave_reseed_interval = _slave_reseed_interval;
+
+    master_reseed_time_interval = _master_reseed_time_interval;
+    slave_reseed_time_interval = _slave_reseed_time_interval;
+
+    return 1;
+}
+
+/*
+ * Locks the given drbg. Locking a drbg which does not have locking
+ * enabled is considered a successful no-op.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int rand_drbg_lock(RAND_DRBG *drbg)
+{
+    if (drbg->lock != NULL)
+        return CRYPTO_THREAD_write_lock(drbg->lock);
+
+    return 1;
+}
+
+/*
+ * Unlocks the given drbg. Unlocking a drbg which does not have locking
+ * enabled is considered a successful no-op.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int rand_drbg_unlock(RAND_DRBG *drbg)
+{
+    if (drbg->lock != NULL)
+        return CRYPTO_THREAD_unlock(drbg->lock);
+
+    return 1;
+}
+
+/*
+ * Enables locking for the given drbg
+ *
+ * Locking can only be enabled if the random generator
+ * is in the uninitialized state.
+ *
+ * Returns 1 on success, 0 on failure.
+ */
+int rand_drbg_enable_locking(RAND_DRBG *drbg)
+{
+    if (drbg->state != DRBG_UNINITIALISED) {
+        RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+                RAND_R_DRBG_ALREADY_INITIALIZED);
+        return 0;
+    }
+
+    if (drbg->lock == NULL) {
+        if (drbg->parent != NULL && drbg->parent->lock == NULL) {
+            RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+                    RAND_R_PARENT_LOCKING_NOT_ENABLED);
+            return 0;
+        }
+
+        drbg->lock = CRYPTO_THREAD_lock_new();
+        if (drbg->lock == NULL) {
+            RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
+                    RAND_R_FAILED_TO_CREATE_LOCK);
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
 /*
  * Get and set the EXDATA
  */
@@ -681,52 +940,35 @@ void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
  *
  * Returns a pointer to the new DRBG instance on success, NULL on failure.
  */
-static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
+static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type)
 {
     RAND_DRBG *drbg;
 
-    drbg = OPENSSL_secure_zalloc(sizeof(RAND_DRBG));
+    drbg = RAND_DRBG_secure_new(rand_drbg_type[drbg_type],
+                                rand_drbg_flags[drbg_type], parent);
     if (drbg == NULL)
         return NULL;
 
-    drbg->lock = CRYPTO_THREAD_lock_new();
-    if (drbg->lock == NULL) {
-        RANDerr(RAND_F_DRBG_SETUP, RAND_R_FAILED_TO_CREATE_LOCK);
+    /* Only the master DRBG needs to have a lock */
+    if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
         goto err;
-    }
-
-    if (RAND_DRBG_set(drbg,
-                      RAND_DRBG_NID, RAND_DRBG_FLAG_CTR_USE_DF) != 1)
-        goto err;
-    if (RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
-                                rand_drbg_cleanup_entropy, NULL, NULL) != 1)
-        goto err;
-
-    if (parent == NULL) {
-        drbg->reseed_interval = MASTER_RESEED_INTERVAL;
-        drbg->reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
-    } else {
-        drbg->parent = parent;
-        drbg->reseed_interval = SLAVE_RESEED_INTERVAL;
-        drbg->reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
-    }
 
     /* enable seed propagation */
-    drbg->reseed_counter = 1;
+    tsan_store(&drbg->reseed_prop_counter, 1);
 
     /*
-     * Ignore instantiation error so support just-in-time instantiation.
+     * Ignore instantiation error to support just-in-time instantiation.
      *
      * The state of the drbg will be checked in RAND_DRBG_generate() and
      * an automatic recovery is attempted.
      */
-    RAND_DRBG_instantiate(drbg,
-                          (const unsigned char *) ossl_pers_string,
-                          sizeof(ossl_pers_string) - 1);
+    (void)RAND_DRBG_instantiate(drbg,
+                                (const unsigned char *) ossl_pers_string,
+                                sizeof(ossl_pers_string) - 1);
     return drbg;
 
 err:
-    drbg_cleanup(drbg);
+    RAND_DRBG_free(drbg);
     return NULL;
 }
 
@@ -743,34 +985,48 @@ DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
     if (!OPENSSL_init_crypto(0, NULL))
         return 0;
 
-    drbg_master = drbg_setup(NULL);
-    drbg_public = drbg_setup(drbg_master);
-    drbg_private = drbg_setup(drbg_master);
-
-    if (drbg_master == NULL || drbg_public == NULL || drbg_private == NULL)
+    if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
         return 0;
 
+    if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
+        goto err1;
+
+    master_drbg = drbg_setup(NULL, RAND_DRBG_TYPE_MASTER);
+    if (master_drbg == NULL)
+        goto err2;
+
     return 1;
+
+err2:
+    CRYPTO_THREAD_cleanup_local(&public_drbg);
+err1:
+    CRYPTO_THREAD_cleanup_local(&private_drbg);
+    return 0;
 }
 
-/* Cleans up the given global DRBG  */
-static void drbg_cleanup(RAND_DRBG *drbg)
+/* Clean up the global DRBGs before exit */
+void rand_drbg_cleanup_int(void)
 {
-    if (drbg != NULL) {
-        RAND_DRBG_uninstantiate(drbg);
-        CRYPTO_THREAD_lock_free(drbg->lock);
-        OPENSSL_secure_clear_free(drbg, sizeof(RAND_DRBG));
+    if (master_drbg != NULL) {
+        RAND_DRBG_free(master_drbg);
+        master_drbg = NULL;
+
+        CRYPTO_THREAD_cleanup_local(&private_drbg);
+        CRYPTO_THREAD_cleanup_local(&public_drbg);
     }
 }
 
-/* Clean up the global DRBGs before exit */
-void rand_drbg_cleanup_int(void)
+void drbg_delete_thread_state(void)
 {
-    drbg_cleanup(drbg_private);
-    drbg_cleanup(drbg_public);
-    drbg_cleanup(drbg_master);
+    RAND_DRBG *drbg;
+
+    drbg = CRYPTO_THREAD_get_local(&public_drbg);
+    CRYPTO_THREAD_set_local(&public_drbg, NULL);
+    RAND_DRBG_free(drbg);
 
-    drbg_private = drbg_public = drbg_master = NULL;
+    drbg = CRYPTO_THREAD_get_local(&private_drbg);
+    CRYPTO_THREAD_set_local(&private_drbg, NULL);
+    RAND_DRBG_free(drbg);
 }
 
 /* Implements the default OpenSSL RAND_bytes() method */
@@ -782,18 +1038,58 @@ static int drbg_bytes(unsigned char *out, int count)
     if (drbg == NULL)
         return 0;
 
-    CRYPTO_THREAD_write_lock(drbg->lock);
     ret = RAND_DRBG_bytes(drbg, out, count);
-    CRYPTO_THREAD_unlock(drbg->lock);
 
     return ret;
 }
 
+/*
+ * Calculates the minimum length of a full entropy buffer
+ * which is necessary to seed (i.e. instantiate) the DRBG
+ * successfully.
+ *
+ * NOTE: There is a copy of this function in drbgtest.c.
+ *       If you change anything here, you need to update
+ *       the copy accordingly.
+ */
+static size_t rand_drbg_seedlen(RAND_DRBG *drbg)
+{
+    /*
+     * If no os entropy source is available then RAND_seed(buffer, bufsize)
+     * is expected to succeed if and only if the buffer length satisfies
+     * the following requirements, which follow from the calculations
+     * in RAND_DRBG_instantiate().
+     */
+    size_t min_entropy = drbg->strength;
+    size_t min_entropylen = drbg->min_entropylen;
+
+    /*
+     * Extra entropy for the random nonce in the absence of a
+     * get_nonce callback, see comment in RAND_DRBG_instantiate().
+     */
+    if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
+        min_entropy += drbg->strength / 2;
+        min_entropylen += drbg->min_noncelen;
+    }
+
+    /*
+     * Convert entropy requirement from bits to bytes
+     * (dividing by 8 without rounding upwards, because
+     * all entropy requirements are divisible by 8).
+     */
+    min_entropy >>= 3;
+
+    /* Return a value that satisfies both requirements */
+    return min_entropy > min_entropylen ? min_entropy : min_entropylen;
+}
+
 /* Implements the default OpenSSL RAND_add() method */
 static int drbg_add(const void *buf, int num, double randomness)
 {
     int ret = 0;
     RAND_DRBG *drbg = RAND_DRBG_get0_master();
+    size_t buflen;
+    size_t seedlen;
 
     if (drbg == NULL)
         return 0;
@@ -801,21 +1097,50 @@ static int drbg_add(const void *buf, int num, double randomness)
     if (num < 0 || randomness < 0.0)
         return 0;
 
-    if (randomness > (double)drbg->max_entropylen) {
+    rand_drbg_lock(drbg);
+    seedlen = rand_drbg_seedlen(drbg);
+
+    buflen = (size_t)num;
+
+    if (buflen < seedlen || randomness < (double) seedlen) {
+#if defined(OPENSSL_RAND_SEED_NONE)
+        /*
+         * If no os entropy source is available, a reseeding will fail
+         * inevitably. So we use a trick to mix the buffer contents into
+         * the DRBG state without forcing a reseeding: we generate a
+         * dummy random byte, using the buffer content as additional data.
+         * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
+         */
+        unsigned char dummy[1];
+
+        ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
+        rand_drbg_unlock(drbg);
+        return ret;
+#else
+        /*
+         * If an os entropy source is avaible then we declare the buffer content
+         * as additional data by setting randomness to zero and trigger a regular
+         * reseeding.
+         */
+        randomness = 0.0;
+#endif
+    }
+
+
+    if (randomness > (double)seedlen) {
         /*
          * The purpose of this check is to bound |randomness| by a
          * relatively small value in order to prevent an integer
          * overflow when multiplying by 8 in the rand_drbg_restart()
-         * call below.
+         * call below. Note that randomness is measured in bytes,
+         * not bits, so this value corresponds to eight times the
+         * security strength.
          */
-        return 0;
+        randomness = (double)seedlen;
     }
 
-    CRYPTO_THREAD_write_lock(drbg->lock);
-    ret = rand_drbg_restart(drbg, buf,
-                            (size_t)(unsigned int)num,
-                            (size_t)(8*randomness));
-    CRYPTO_THREAD_unlock(drbg->lock);
+    ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
+    rand_drbg_unlock(drbg);
 
     return ret;
 }
@@ -835,9 +1160,9 @@ static int drbg_status(void)
     if (drbg == NULL)
         return 0;
 
-    CRYPTO_THREAD_write_lock(drbg->lock);
+    rand_drbg_lock(drbg);
     ret = drbg->state == DRBG_READY ? 1 : 0;
-    CRYPTO_THREAD_unlock(drbg->lock);
+    rand_drbg_unlock(drbg);
     return ret;
 }
 
@@ -851,7 +1176,7 @@ RAND_DRBG *RAND_DRBG_get0_master(void)
     if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
         return NULL;
 
-    return drbg_master;
+    return master_drbg;
 }
 
 /*
@@ -860,10 +1185,19 @@ RAND_DRBG *RAND_DRBG_get0_master(void)
  */
 RAND_DRBG *RAND_DRBG_get0_public(void)
 {
+    RAND_DRBG *drbg;
+
     if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
         return NULL;
 
-    return drbg_public;
+    drbg = CRYPTO_THREAD_get_local(&public_drbg);
+    if (drbg == NULL) {
+        if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
+            return NULL;
+        drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PUBLIC);
+        CRYPTO_THREAD_set_local(&public_drbg, drbg);
+    }
+    return drbg;
 }
 
 /*
@@ -872,10 +1206,19 @@ RAND_DRBG *RAND_DRBG_get0_public(void)
  */
 RAND_DRBG *RAND_DRBG_get0_private(void)
 {
+    RAND_DRBG *drbg;
+
     if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
         return NULL;
 
-    return drbg_private;
+    drbg = CRYPTO_THREAD_get_local(&private_drbg);
+    if (drbg == NULL) {
+        if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
+            return NULL;
+        drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PRIVATE);
+        CRYPTO_THREAD_set_local(&private_drbg, drbg);
+    }
+    return drbg;
 }
 
 RAND_METHOD rand_meth = {