Allocate DRBG additional data pool from non-secure memory

The additional data allocates 12K per DRBG instance in the
secure memory, which is not necessary. Also nonces are not
considered secret.

[extended tests]
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9424)

crypto/include/internal/rand_int.h

@@ -52,7 +52,8 @@ void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out);
 /*
  * RAND_POOL functions
  */
-RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len);
+RAND_POOL *rand_pool_new(int entropy_requested, int secure,
+                         size_t min_len, size_t max_len);
 RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
                             size_t entropy);
 void rand_pool_free(RAND_POOL *pool);

crypto/rand/drbg_lib.c

@@ -664,7 +664,7 @@ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
     if (drbg->adin_pool == NULL) {
         if (drbg->type == 0)
             goto err;
-        drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
+        drbg->adin_pool = rand_pool_new(0, 0, 0, drbg->max_adinlen);
         if (drbg->adin_pool == NULL)
             goto err;
     }

crypto/rand/rand_lcl.h

@@ -150,6 +150,7 @@ struct rand_pool_st {
     size_t len; /* current number of random bytes contained in the pool */
 
     int attached;  /* true pool was attached to existing buffer */
+    int secure;    /* 1: allocated on the secure heap, 0: otherwise */
 
     size_t min_len; /* minimum number of random bytes requested */
     size_t max_len; /* maximum number of random bytes (allocated buffer size) */

crypto/rand/rand_lib.c

@@ -150,7 +150,7 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
         pool = drbg->seed_pool;
         pool->entropy_requested = entropy;
     } else {
-        pool = rand_pool_new(entropy, min_len, max_len);
+        pool = rand_pool_new(entropy, drbg->secure, min_len, max_len);
         if (pool == NULL)
             return 0;
     }
@@ -216,8 +216,12 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
                                unsigned char *out, size_t outlen)
 {
-    if (drbg->seed_pool == NULL)
-        OPENSSL_secure_clear_free(out, outlen);
+    if (drbg->seed_pool == NULL) {
+        if (drbg->secure)
+            OPENSSL_secure_clear_free(out, outlen);
+        else
+            OPENSSL_clear_free(out, outlen);
+    }
 }
 
 
@@ -238,7 +242,7 @@ size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
     } data;
 
     memset(&data, 0, sizeof(data));
-    pool = rand_pool_new(0, min_len, max_len);
+    pool = rand_pool_new(0, 0, min_len, max_len);
     if (pool == NULL)
         return 0;
 
@@ -267,7 +271,7 @@ size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
 void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
                              unsigned char *out, size_t outlen)
 {
-    OPENSSL_secure_clear_free(out, outlen);
+    OPENSSL_clear_free(out, outlen);
 }
 
 /*
@@ -402,7 +406,7 @@ int RAND_poll(void)
 
     } else {
         /* fill random pool and seed the current legacy RNG */
-        pool = rand_pool_new(RAND_DRBG_STRENGTH,
+        pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
                              (RAND_DRBG_STRENGTH + 7) / 8,
                              RAND_POOL_MAX_LENGTH);
         if (pool == NULL)
@@ -429,7 +433,8 @@ err:
  * Allocate memory and initialize a new random pool
  */
 
-RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len)
+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));
 
@@ -442,13 +447,18 @@ RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len)
     pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
         RAND_POOL_MAX_LENGTH : max_len;
 
-    pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
+    if (secure)
+        pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
+    else
+        pool->buffer = OPENSSL_zalloc(pool->max_len);
+
     if (pool->buffer == NULL) {
         RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
         goto err;
     }
 
     pool->entropy_requested = entropy_requested;
+    pool->secure = secure;
 
     return pool;
 
@@ -503,8 +513,13 @@ void rand_pool_free(RAND_POOL *pool)
      * to rand_pool_attach() as `const unsigned char*`.
      * (see corresponding comment in rand_pool_attach()).
      */
-    if (!pool->attached)
-        OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+    if (!pool->attached) {
+        if (pool->secure)
+            OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+        else
+            OPENSSL_clear_free(pool->buffer, pool->max_len);
+    }
+
     OPENSSL_free(pool);
 }