diff --git a/fips/rand/fips_drbgvs.c b/fips/rand/fips_drbgvs.c
index 9aae88c3e..214e3c340 100644
--- a/fips/rand/fips_drbgvs.c
+++ b/fips/rand/fips_drbgvs.c
@@ -182,7 +182,7 @@ int main(int argc,char **argv)
 	int r, nid = 0;
 	int pr = 0;
 	char buf[2048], lbuf[2048];
-	unsigned char randout[2048];
+	unsigned char *randout = NULL;
 	char *keyword = NULL, *value = NULL;
 
 	unsigned char *ent = NULL, *nonce = NULL, *pers = NULL, *adin = NULL;
@@ -298,6 +298,8 @@ int main(int argc,char **argv)
 			else
 				exit(1);
 			}
+		if (!strcmp(keyword, "[ReturnedBitsLen"))
+			randoutlen = atoi(value) / 8;
 
 		if (!strcmp(keyword, "EntropyInput"))
 			{
@@ -327,7 +329,11 @@ int main(int argc,char **argv)
 			FIPS_drbg_set_callbacks(dctx, test_entropy, 0, 0,
 							test_nonce, 0);
 			FIPS_drbg_set_app_data(dctx, &t);
-			randoutlen = (int)FIPS_drbg_get_blocklength(dctx);
+			if (randoutlen == 0)
+				randoutlen = (int)FIPS_drbg_get_blocklength(dctx);
+			if (randout)
+				OPENSSL_free(randout);
+			randout = OPENSSL_malloc(randoutlen);
 			r = FIPS_drbg_instantiate(dctx, pers, perslen);
 			if (!r)
 				{
@@ -406,6 +412,8 @@ int main(int argc,char **argv)
 			}
 
 		}
+	if (randout)
+		OPENSSL_free(randout);
 	if (in && in != stdin)
 		fclose(in);
 	if (out && out != stdout)