diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index d31735c5c45a1b01ca266072995edf3a78f30c8e..6123d148a4027ceff64b7cc66ae798296ecf2d72 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -174,7 +174,7 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
             if (RAND_DRBG_generate(drbg->parent,
                                    buffer, bytes_needed,
                                    prediction_resistance,
-                                   (unsigned char *)drbg, sizeof(*drbg)) != 0)
+                                   NULL, 0) != 0)
                 bytes = bytes_needed;
             rand_drbg_unlock(drbg->parent);