diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 3ec88cd4f..1635aabd2 100644
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -712,7 +712,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
  * zero otherwise. */
 int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx);
 
-/* BN_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
+/* BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
  * algorithm for the values provided and can run in constant time if
  * |BN_FLG_CONSTTIME| is set for |p|. It returns one on success or zero
  * otherwise. */
diff --git a/crypto/bn/random.c b/crypto/bn/random.c
index 06e4c0fde..924aad71d 100644
--- a/crypto/bn/random.c
+++ b/crypto/bn/random.c
@@ -117,6 +117,10 @@ int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) {
   uint8_t *buf = NULL;
   int ret = 0, bit, bytes, mask;
 
+  if (rnd == NULL) {
+    return 0;
+  }
+
   if (bits == 0) {
     BN_zero(rnd);
     return 1;
@@ -252,6 +256,10 @@ int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv,
   uint8_t *k_bytes = NULL;
   int ret = 0;
 
+  if (out == NULL) {
+    return 0;
+  }
+
   if (BN_is_zero(range)) {
     OPENSSL_PUT_ERROR(BN, BN_generate_dsa_nonce, BN_R_DIV_BY_ZERO);
     goto err;