CTR, HASH and HMAC DRBGs in provider

Move the three different DRBGs to the provider.

As part of the move, the DRBG specific data was pulled out of a common
structure and into their own structures.  Only these smaller structures are
securely allocated.  This saves quite a bit of secure memory:

    +-------------------------------+
    | DRBG         | Bytes | Secure |
    +--------------+-------+--------+
    | HASH         |  376  |   512  |
    | HMAC         |  168  |   256  |
    | CTR          |  176  |   256  |
    | Common (new) |  320  |     0  |
    | Common (old) |  592  |  1024  |
    +--------------+-------+--------+

Bytes is the structure size on the X86/64.
Secure is the number of bytes of secure memory used (power of two allocator).

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/11682)

4 files changed, 341 insertions, 1108 deletions

diff --git a/crypto/rand/build.info b/crypto/rand/build.info
index 7840428045..b7a4d598f1 100644
--- a/crypto/rand/build.info
+++ b/crypto/rand/build.info
@@ -1,16 +1,10 @@
 LIBS=../../libcrypto
 
-$COMMON=rand_pool.c rand_lib.c drbg_lib.c drbg_ctr.c drbg_hash.c drbg_hmac.c
-$CRYPTO=rand_unix.c rand_win.c randfile.c rand_err.c
+$COMMON=drbg_lib.c rand_lib.c
+$CRYPTO=randfile.c rand_err.c
 
 IF[{- !$disabled{'egd'} -}]
-  $CYPTO=$CYPTO rand_egd.c
-ENDIF
-IF[{- $config{target} =~ /vxworks/i -}]
-  $CYPTO=$CYPTO rand_vxworks.c
-ENDIF
-IF[{- $config{target} =~ /vms/i -}]
-  $CYPTO=$CYPTO rand_vms.c
+  $CRYPTO=$CRYPTO rand_egd.c
 ENDIF
 
 
diff --git a/crypto/rand/drbg_lib.c b/crypto/rand/drbg_lib.c
index 94a4e98d73..80759cbfaf 100644
--- a/crypto/rand/drbg_lib.c
+++ b/crypto/rand/drbg_lib.c
@@ -11,10 +11,10 @@
 #include <openssl/crypto.h>
 #include <openssl/err.h>
 #include <openssl/rand.h>
+#include <openssl/core_names.h>
 #include "rand_local.h"
 #include "internal/thread_once.h"
 #include "crypto/rand.h"
-#include "crypto/rand_pool.h"
 #include "crypto/cryptlib.h"
 
 /*
@@ -37,6 +37,7 @@ typedef struct drbg_global_st {
      *
      * There are three shared DRBG instances: <master>, <public>, and <private>.
      */
+    CRYPTO_RWLOCK *lock;
 
     /*
      * The <master> DRBG
@@ -70,14 +71,6 @@ typedef struct drbg_global_st {
     CRYPTO_THREAD_LOCAL private_drbg;
 } DRBG_GLOBAL;
 
-typedef struct drbg_nonce_global_st {
-    CRYPTO_RWLOCK *rand_nonce_lock;
-    int rand_nonce_count;
-} DRBG_NONCE_GLOBAL;
-
-/* NIST SP 800-90A DRBG recommends the use of a personalization string. */
-static const char ossl_pers_string[] = DRBG_DEFAULT_PERS_STRING;
-
 #define RAND_DRBG_TYPE_FLAGS    ( \
     RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
 
@@ -110,45 +103,76 @@ static const unsigned int rand_drbg_used_flags =
 
 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type);
 
-static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
-                                int secure,
-                                int type,
-                                unsigned int flags,
-                                RAND_DRBG *parent);
-
-static int rand_drbg_set(RAND_DRBG *drbg, int type, unsigned int flags);
-static int rand_drbg_init_method(RAND_DRBG *drbg);
-
-static int is_ctr(int type)
+static int get_drbg_params(int type, unsigned int flags, const char **name,
+                           OSSL_PARAM params[3])
 {
+    OSSL_PARAM *p = params;
+
     switch (type) {
-    case NID_aes_128_ctr:
-    case NID_aes_192_ctr:
-    case NID_aes_256_ctr:
+    case 0:
         return 1;
     default:
         return 0;
+
+#define CTR(v)                                                              \
+    *name = "CTR-DRBG";                                                     \
+    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER, v, 0)
+
+    case NID_aes_128_ctr:
+        CTR(SN_aes_128_ctr);
+        break;
+    case NID_aes_192_ctr:
+        CTR(SN_aes_192_ctr);
+        break;
+    case NID_aes_256_ctr:
+        CTR(SN_aes_256_ctr);
+        break;
+
+#define DGST(v)                                                             \
+    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST, v, 0);  \
+    if ((flags & RAND_DRBG_FLAG_HMAC) == 0) {                               \
+        *name = "HASH-DRBG";                                                \
+    } else {                                                                \
+        *name = "HMAC-DRBG";                                                \
+        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_MAC,        \
+                                                SN_hmac, 0);                \
     }
-}
 
-static int is_digest(int type)
-{
-    switch (type) {
     case NID_sha1:
+        DGST(SN_sha1);
+        break;
     case NID_sha224:
+        DGST(SN_sha224);
+        break;
     case NID_sha256:
+        DGST(SN_sha256);
+        break;
     case NID_sha384:
+        DGST(SN_sha384);
+        break;
     case NID_sha512:
+        DGST(SN_sha512);
+        break;
     case NID_sha512_224:
+        DGST(SN_sha512_224);
+        break;
     case NID_sha512_256:
+        DGST(SN_sha512_256);
+        break;
     case NID_sha3_224:
+        DGST(SN_sha3_224);
+        break;
     case NID_sha3_256:
+        DGST(SN_sha3_256);
+        break;
     case NID_sha3_384:
+        DGST(SN_sha3_384);
+        break;
     case NID_sha3_512:
-        return 1;
-    default:
-        return 0;
+        DGST(SN_sha3_512);
     }
+    *p = OSSL_PARAM_construct_end();
+    return 1;
 }
 
 /*
@@ -170,23 +194,23 @@ static void *drbg_ossl_ctx_new(OPENSSL_CTX *libctx)
      OPENSSL_init_crypto(0, NULL);
 #endif
 
+    dgbl->lock = CRYPTO_THREAD_lock_new();
+    if (dgbl->lock == NULL)
+        goto err0;
+
     if (!CRYPTO_THREAD_init_local(&dgbl->private_drbg, NULL))
         goto err1;
 
     if (!CRYPTO_THREAD_init_local(&dgbl->public_drbg, NULL))
         goto err2;
 
-    dgbl->master_drbg = drbg_setup(libctx, NULL, RAND_DRBG_TYPE_MASTER);
-    if (dgbl->master_drbg == NULL)
-        goto err3;
-
     return dgbl;
 
- err3:
-    CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
  err2:
     CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
  err1:
+    CRYPTO_THREAD_lock_free(dgbl->lock);
+ err0:
     OPENSSL_free(dgbl);
     return NULL;
 }
@@ -198,6 +222,7 @@ static void drbg_ossl_ctx_free(void *vdgbl)
     if (dgbl == NULL)
         return;
 
+    CRYPTO_THREAD_lock_free(dgbl->lock);
     RAND_DRBG_free(dgbl->master_drbg);
     CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
     CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
@@ -210,104 +235,12 @@ static const OPENSSL_CTX_METHOD drbg_ossl_ctx_method = {
     drbg_ossl_ctx_free,
 };
 
-/*
- * drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce()
- * which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since
- * drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock
- * to be in a different global data object. Otherwise we will go into an
- * infinite recursion loop.
- */
-static void *drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx)
-{
-    DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl));
-
-    if (dngbl == NULL)
-        return NULL;
-
-    dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new();
-    if (dngbl->rand_nonce_lock == NULL) {
-        OPENSSL_free(dngbl);
-        return NULL;
-    }
-
-    return dngbl;
-}
-
-static void drbg_nonce_ossl_ctx_free(void *vdngbl)
-{
-    DRBG_NONCE_GLOBAL *dngbl = vdngbl;
-
-    if (dngbl == NULL)
-        return;
-
-    CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock);
-
-    OPENSSL_free(dngbl);
-}
-
-static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = {
-    drbg_nonce_ossl_ctx_new,
-    drbg_nonce_ossl_ctx_free,
-};
-
 static DRBG_GLOBAL *drbg_get_global(OPENSSL_CTX *libctx)
 {
     return openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_INDEX,
                                 &drbg_ossl_ctx_method);
 }
 
-/* Implements the get_nonce() callback (see RAND_DRBG_set_callbacks()) */
-size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
-                           unsigned char **pout,
-                           int entropy, size_t min_len, size_t max_len)
-{
-    size_t ret = 0;
-    RAND_POOL *pool;
-    DRBG_NONCE_GLOBAL *dngbl
-        = openssl_ctx_get_data(drbg->libctx, OPENSSL_CTX_DRBG_NONCE_INDEX,
-                               &drbg_nonce_ossl_ctx_method);
-    struct {
-        void *instance;
-        int count;
-    } data;
-
-    if (dngbl == NULL)
-        return 0;
-
-    memset(&data, 0, sizeof(data));
-    pool = rand_pool_new(0, 0, min_len, max_len);
-    if (pool == NULL)
-        return 0;
-
-    if (rand_pool_add_nonce_data(pool) == 0)
-        goto err;
-
-    data.instance = drbg;
-    CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count,
-                      dngbl->rand_nonce_lock);
-
-    if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0)
-        goto err;
-
-    ret   = rand_pool_length(pool);
-    *pout = rand_pool_detach(pool);
-
- err:
-    rand_pool_free(pool);
-
-    return ret;
-}
-
-/*
- * Implements the cleanup_nonce() callback (see RAND_DRBG_set_callbacks())
- *
- */
-void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
-                             unsigned char *out, size_t outlen)
-{
-    OPENSSL_clear_free(out, outlen);
-}
-
 /*
  * Set the |drbg|'s callback data pointer for the entropy and nonce callbacks
  *
@@ -322,8 +255,8 @@ void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
  */
 int RAND_DRBG_set_callback_data(RAND_DRBG *drbg, void *data)
 {
-    if (drbg->state != DRBG_UNINITIALISED
-        || drbg->parent != NULL)
+    if (EVP_RAND_state(drbg->rand) != EVP_RAND_STATE_UNINITIALISED
+            || drbg->parent != NULL)
         return 0;
 
     drbg->callback_data = data;
@@ -345,68 +278,71 @@ void *RAND_DRBG_get_callback_data(RAND_DRBG *drbg)
  */
 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
 {
-    return rand_drbg_set(drbg, type, flags) && rand_drbg_init_method(drbg);
-}
+    OSSL_PARAM params[6], *p = params;
+    unsigned int reseed_interval;
+    time_t reseed_time_interval;
+    const char *name = NULL;
+    EVP_RAND *rand;
+    EVP_RAND_CTX *pctx;
+    int use_df;
 
-static int rand_drbg_set(RAND_DRBG *drbg, int type, unsigned int flags)
-{
     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)) {
-        if (drbg->meth != NULL)
-            drbg->meth->uninstantiate(drbg);
-        rand_pool_free(drbg->adin_pool);
-        drbg->adin_pool = NULL;
+    if (drbg->parent == NULL) {
+        reseed_interval = master_reseed_interval;
+        reseed_time_interval = master_reseed_time_interval;
+    } else {
+        reseed_interval = slave_reseed_interval;
+        reseed_time_interval = slave_reseed_time_interval;
+    }
+    *p++ = OSSL_PARAM_construct_uint(OSSL_DRBG_PARAM_RESEED_REQUESTS,
+                                     &reseed_interval);
+    *p++ = OSSL_PARAM_construct_time_t(OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL,
+                                       &reseed_time_interval);
+    use_df = (flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0;
+    *p++ = OSSL_PARAM_construct_int(OSSL_DRBG_PARAM_USE_DF, &use_df);
+
+    if (!get_drbg_params(type, flags, &name, p)) {
+        RANDerr(0, RAND_R_UNSUPPORTED_DRBG_TYPE);
+        return 0;
     }
 
-    drbg->state = DRBG_UNINITIALISED;
+    rand = EVP_RAND_fetch(drbg->libctx, name, NULL);
+    if (rand == NULL) {
+        RANDerr(0, RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
+        return 0;
+    }
+
+    EVP_RAND_CTX_free(drbg->rand);
+    drbg->rand = NULL;
+
     drbg->flags = flags;
     drbg->type = type;
-    drbg->meth = NULL;
 
-    if (type == 0 || is_ctr(type) || is_digest(type))
-        return 1;
+    pctx = drbg->parent != NULL ? drbg->parent->rand : NULL;
+    drbg->rand = EVP_RAND_CTX_new(rand, pctx);
+    EVP_RAND_free(rand);
+    if (drbg->rand == NULL) {
+        RANDerr(0, RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
+        goto err;
+    }
 
+    if (!EVP_RAND_set_ctx_params(drbg->rand, params)) {
+        RANDerr(0, RAND_R_ERROR_INITIALISING_DRBG);
+        goto err;
+    }
+    return 1;
+err:
+    EVP_RAND_CTX_free(drbg->rand);
+    drbg->rand = NULL;
     drbg->type = 0;
     drbg->flags = 0;
-    RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
-
     return 0;
 }
 
-static int rand_drbg_init_method(RAND_DRBG *drbg)
-{
-    int ret;
-
-    if (drbg->meth != NULL)
-        return 1;
-
-    if (is_ctr(drbg->type)) {
-        ret = drbg_ctr_init(drbg);
-    } else if (is_digest(drbg->type)) {
-        if (drbg->flags & RAND_DRBG_FLAG_HMAC)
-            ret = drbg_hmac_init(drbg);
-        else
-            ret = drbg_hash_init(drbg);
-    } else {
-        /* other cases should already be excluded */
-        RANDerr(RAND_F_RAND_DRBG_INIT_METHOD, ERR_R_INTERNAL_ERROR);
-        drbg->type = 0;
-        drbg->flags = 0;
-        return 0;
-    }
-
-    if (ret == 0) {
-        drbg->state = DRBG_ERROR;
-        RANDerr(RAND_F_RAND_DRBG_INIT_METHOD, RAND_R_ERROR_INITIALISING_DRBG);
-    }
-    return ret;
-}
-
 /*
  * Set/initialize default |type| and |flag| for new drbg instances.
  *
@@ -415,7 +351,10 @@ static int rand_drbg_init_method(RAND_DRBG *drbg)
 int RAND_DRBG_set_defaults(int type, unsigned int flags)
 {
     int all;
-    if (!(is_digest(type) || is_ctr(type))) {
+    const char *name;
+    OSSL_PARAM params[3];
+
+    if (!get_drbg_params(type, flags, &name, params)) {
         RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
         return 0;
     }
@@ -443,20 +382,17 @@ int RAND_DRBG_set_defaults(int type, unsigned int flags)
 
 
 /*
- * 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.
+ * Allocate memory and initialize a new DRBG.
  * 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.
  */
 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
-                                int secure,
                                 int type,
                                 unsigned int flags,
                                 RAND_DRBG *parent)
 {
-    RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg))
-                             : OPENSSL_zalloc(sizeof(*drbg));
+    RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
 
     if (drbg == NULL) {
         RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
@@ -464,49 +400,11 @@ static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
     }
 
     drbg->libctx = ctx;
-    drbg->secure = secure && CRYPTO_secure_allocated(drbg);
-    drbg->fork_id = openssl_get_fork_id();
     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 (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:
@@ -518,7 +416,7 @@ static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
 RAND_DRBG *RAND_DRBG_new_ex(OPENSSL_CTX *ctx, int type, unsigned int flags,
                             RAND_DRBG *parent)
 {
-    return rand_drbg_new(ctx, 0, type, flags, parent);
+    return rand_drbg_new(ctx, type, flags, parent);
 }
 
 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
@@ -526,16 +424,6 @@ RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
     return RAND_DRBG_new_ex(NULL, type, flags, parent);
 }
 
-RAND_DRBG *RAND_DRBG_secure_new_ex(OPENSSL_CTX *ctx, int type,
-                                   unsigned int flags, RAND_DRBG *parent)
-{
-    return rand_drbg_new(ctx, 1, type, flags, parent);
-}
-
-RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
-{
-    return RAND_DRBG_secure_new_ex(NULL, type, flags, parent);
-}
 /*
  * Uninstantiate |drbg| and free all memory.
  */
@@ -544,18 +432,8 @@ void RAND_DRBG_free(RAND_DRBG *drbg)
     if (drbg == NULL)
         return;
 
-    if (drbg->meth != NULL)
-        drbg->meth->uninstantiate(drbg);
-    rand_pool_free(drbg->adin_pool);
-    CRYPTO_THREAD_lock_free(drbg->lock);
-#ifndef FIPS_MODULE
     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_RAND_DRBG, drbg, &drbg->ex_data);
-#endif
-
-    if (drbg->secure)
-        OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
-    else
-        OPENSSL_clear_free(drbg, sizeof(*drbg));
+    OPENSSL_free(drbg);
 }
 
 /*
@@ -569,92 +447,8 @@ void RAND_DRBG_free(RAND_DRBG *drbg)
 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
                           const unsigned char *pers, size_t perslen)
 {
-    unsigned char *nonce = NULL, *entropy = NULL;
-    size_t noncelen = 0, entropylen = 0;
-    size_t min_entropy, min_entropylen, max_entropylen;
-
-    if (drbg->meth == NULL && !rand_drbg_init_method(drbg)) {
-        RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
-                RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
-        goto end;
-    }
-
-    min_entropy = drbg->strength;
-    min_entropylen = drbg->min_entropylen;
-    max_entropylen = drbg->max_entropylen;
-
-    if (perslen > drbg->max_perslen) {
-        RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
-                RAND_R_PERSONALISATION_STRING_TOO_LONG);
-        goto end;
-    }
-
-    if (drbg->state != DRBG_UNINITIALISED) {
-        if (drbg->state == DRBG_ERROR)
-            RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_IN_ERROR_STATE);
-        else
-            RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ALREADY_INSTANTIATED);
-        goto end;
-    }
-
-    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 accommodate 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, 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->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);
-            goto end;
-        }
-    }
-
-    if (!drbg->meth->instantiate(drbg, entropy, entropylen,
-                         nonce, noncelen, pers, perslen)) {
-        RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
-        goto end;
-    }
-
-    drbg->state = DRBG_READY;
-    drbg->reseed_gen_counter = 1;
-    drbg->reseed_time = time(NULL);
-    tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
-
- end:
-    if (entropy != NULL && drbg->cleanup_entropy != NULL)
-        drbg->cleanup_entropy(drbg, entropy, entropylen);
-    if (nonce != NULL && drbg->cleanup_nonce != NULL)
-        drbg->cleanup_nonce(drbg, nonce, noncelen);
-    if (drbg->state == DRBG_READY)
-        return 1;
-    return 0;
+    return EVP_RAND_instantiate(drbg->rand, EVP_RAND_strength(drbg->rand), 0,
+                                pers, perslen);
 }
 
 /*
@@ -667,10 +461,9 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg,
 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
 {
     int index = -1, type, flags;
-    if (drbg->meth != NULL) {
-        drbg->meth->uninstantiate(drbg);
-        drbg->meth = NULL;
-    }
+
+    if (!EVP_RAND_uninstantiate(drbg->rand))
+        return 0;
 
     /* The reset uses the default values for type and flags */
     if (drbg->flags & RAND_DRBG_FLAG_MASTER)
@@ -687,7 +480,7 @@ int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
         flags = drbg->flags;
         type = drbg->type;
     }
-    return rand_drbg_set(drbg, type, flags);
+    return RAND_DRBG_set(drbg, type, flags);
 }
 
 /*
@@ -701,288 +494,152 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg,
                      const unsigned char *adin, size_t adinlen,
                      int prediction_resistance)
 {
-    unsigned char *entropy = NULL;
-    size_t entropylen = 0;
-
-    if (drbg->state == DRBG_ERROR) {
-        RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
-        return 0;
-    }
-    if (drbg->state == DRBG_UNINITIALISED) {
-        RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
-        return 0;
-    }
-
-    if (adin == NULL) {
-        adinlen = 0;
-    } 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,
-                                       prediction_resistance);
-    if (entropylen < drbg->min_entropylen
-            || entropylen > drbg->max_entropylen) {
-        RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
-        goto end;
-    }
-
-    if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
-        goto end;
-
-    drbg->state = DRBG_READY;
-    drbg->reseed_gen_counter = 1;
-    drbg->reseed_time = time(NULL);
-    tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
-
- end:
-    if (entropy != NULL && drbg->cleanup_entropy != NULL)
-        drbg->cleanup_entropy(drbg, entropy, entropylen);
-    if (drbg->state == DRBG_READY)
-        return 1;
-    return 0;
+    return EVP_RAND_reseed(drbg->rand, prediction_resistance, NULL, 0,
+                           adin, adinlen);
 }
 
 /*
- * Restart |drbg|, using the specified entropy or additional input
- *
- * Tries its best to get the drbg instantiated by all means,
- * regardless of its current state.
+ * Generate |outlen| bytes into the buffer at |out|.  Reseed if we need
+ * to or if |prediction_resistance| is set.  Additional input can be
+ * sent in |adin| and |adinlen|.
  *
- * Optionally, a |buffer| of |len| random bytes can be passed,
- * which is assumed to contain at least |entropy| bits of entropy.
+ * Requires that drbg->lock is already locked for write, if non-null.
  *
- * If |entropy| > 0, the buffer content is used as entropy input.
+ * Returns 1 on success, 0 on failure.
  *
- * If |entropy| == 0, the buffer content is used as additional input
+ */
+int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
+                       int prediction_resistance,
+                       const unsigned char *adin, size_t adinlen)
+{
+    return EVP_RAND_generate(drbg->rand, out, outlen, 0,
+                             prediction_resistance, adin, adinlen);
+}
+
+/*
+ * Generates |outlen| random bytes and stores them in |out|. It will
+ * using the given |drbg| to generate the bytes.
  *
- * Returns 1 on success, 0 on failure.
+ * Requires that drbg->lock is already locked for write, if non-null.
  *
- * This function is used internally only.
+ * Returns 1 on success 0 on failure.
  */
-int rand_drbg_restart(RAND_DRBG *drbg,
-                      const unsigned char *buffer, size_t len, size_t entropy)
+int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
 {
-    int reseeded = 0;
-    const unsigned char *adin = NULL;
-    size_t adinlen = 0;
-
-    if (drbg->seed_pool != NULL) {
-        RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
-        drbg->state = DRBG_ERROR;
-        rand_pool_free(drbg->seed_pool);
-        drbg->seed_pool = NULL;
+    return EVP_RAND_generate(drbg->rand, out, outlen, 0, 0, NULL, 0);
+}
+
+/* DRBG call back shims */
+static int rand_drbg_get_entroy_cb(const OSSL_PARAM *params, OSSL_PARAM *out,
+                                   void *vdrbg)
+{
+    RAND_DRBG *drbg = (RAND_DRBG *)vdrbg;
+    int entropy = 0, prediction_resistance = 0;
+    size_t min_len = 0, max_len = 2048;
+    const OSSL_PARAM *p;
+    OSSL_PARAM *q;
+
+    if (drbg->get_entropy == NULL)
         return 0;
-    }
 
-    if (buffer != NULL) {
-        if (entropy > 0) {
-            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->seed_pool = rand_pool_attach(buffer, len, entropy);
-            if (drbg->seed_pool == NULL)
-                return 0;
-        } 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;
-            adinlen = len;
-        }
-    }
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_ENTROPY_REQUIRED);
+    if (p == NULL || !OSSL_PARAM_get_int(p, &entropy))
+        return 0;
 
-    /* repair error state */
-    if (drbg->state == DRBG_ERROR)
-        RAND_DRBG_uninstantiate(drbg);
-
-    /* repair uninitialized state */
-    if (drbg->state == DRBG_UNINITIALISED) {
-        /* reinstantiate drbg */
-        RAND_DRBG_instantiate(drbg,
-                              (const unsigned char *) ossl_pers_string,
-                              sizeof(ossl_pers_string) - 1);
-        /* already reseeded. prevent second reseeding below */
-        reseeded = (drbg->state == DRBG_READY);
-    }
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_PREDICTION_RESISTANCE);
+    if (p == NULL || !OSSL_PARAM_get_int(p, &prediction_resistance))
+        return 0;
 
-    /* refresh current state if entropy or additional input has been provided */
-    if (drbg->state == DRBG_READY) {
-        if (adin != NULL) {
-            /*
-             * mix in additional input without reseeding
-             *
-             * Similar to RAND_DRBG_reseed(), but the provided additional
-             * data |adin| is mixed into the current state without pulling
-             * entropy from the trusted entropy source using get_entropy().
-             * This is not a reseeding in the strict sense of NIST SP 800-90A.
-             */
-            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, 0);
-        }
-    }
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_MAX_LENGTH);
+    if (p == NULL || !OSSL_PARAM_get_size_t(p, &max_len))
+        return 0;
 
-    rand_pool_free(drbg->seed_pool);
-    drbg->seed_pool = NULL;
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_MIN_LENGTH);
+    if (p == NULL || !OSSL_PARAM_get_size_t(p, &min_len))
+        return 0;
+
+    q = OSSL_PARAM_locate(out, OSSL_DRBG_PARAM_RANDOM_DATA);
+    if (q == NULL || q->data_type != OSSL_PARAM_OCTET_PTR || q->data == NULL)
+        return 0;
 
-    return drbg->state == DRBG_READY;
+    q->return_size = drbg->get_entropy(drbg, (unsigned char **)q->data, entropy,
+                                       min_len, max_len, prediction_resistance);
+    return 1;
 }
 
-/*
- * Generate |outlen| bytes into the buffer at |out|.  Reseed if we need
- * to or if |prediction_resistance| is set.  Additional input can be
- * sent in |adin| and |adinlen|.
- *
- * Requires that drbg->lock is already locked for write, if non-null.
- *
- * Returns 1 on success, 0 on failure.
- *
- */
-int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
-                       int prediction_resistance,
-                       const unsigned char *adin, size_t adinlen)
+static int rand_drbg_cleanup_entropy_cb(const OSSL_PARAM *params, void *vdrbg)
 {
-    int fork_id;
-    int reseed_required = 0;
-
-    if (drbg->state != DRBG_READY) {
-        /* try to recover from previous errors */
-        rand_drbg_restart(drbg, NULL, 0, 0);
-
-        if (drbg->state == DRBG_ERROR) {
-            RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
-            return 0;
-        }
-        if (drbg->state == DRBG_UNINITIALISED) {
-            RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
-            return 0;
-        }
-    }
+    RAND_DRBG *drbg = (RAND_DRBG *)vdrbg;
+    const OSSL_PARAM *p;
+    size_t sz;
 
-    if (outlen > drbg->max_request) {
-        RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
+    if (drbg->cleanup_entropy == NULL)
         return 0;
-    }
-    if (adinlen > drbg->max_adinlen) {
-        RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
+
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_SIZE);
+    if (p == NULL || !OSSL_PARAM_get_size_t(p, &sz))
         return 0;
-    }
 
-    fork_id = openssl_get_fork_id();
+    p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_RANDOM_DATA);
+    if (p == NULL || p->data_type != OSSL_PARAM_OCTET_PTR)
+        return 0;
 
-    if (drbg->fork_id != fork_id) {
-        drbg->fork_id = fork_id;
-        reseed_required = 1;
-    }
+    drbg->cleanup_entropy(drbg, p->data, sz);
+    return 1;
+}
 
-    if (drbg->reseed_interval > 0) {
-        if (drbg->reseed_gen_counter > drbg->reseed_interval)
-            reseed_required = 1;
-    }
-    if (drbg->reseed_time_interval > 0) {
-        time_t now = time(NULL);
-        if (now < drbg->reseed_time
-            || now - drbg->reseed_time >= drbg->reseed_time_interval)
-            reseed_required = 1;
-    }
-    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;
-    }
+static int rand_drbg_get_nonce_cb(const OSSL_PARAM *params, OSSL_PARAM *out,
+                                  void *vdrbg)
+{
+    RAND_DRBG *drbg = (RAND_DRBG *)vdrbg;
+    int entropy = 0;
+    size_t min_len = 0, max_len = 10240;
+    co