Make use of bn_rand_interval() where appropriate.

ok beck jsing

1 files changed, 9 insertions, 6 deletions

diff --git a/src/lib/libcrypto/dh/dh_key.c b/src/lib/libcrypto/dh/dh_key.c
index 2cbf128d80..17df620ec5 100644
--- a/src/lib/libcrypto/dh/dh_key.c
+++ b/src/lib/libcrypto/dh/dh_key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dh_key.c,v 1.31 2018/11/05 23:50:05 tb Exp $ */
+/* $OpenBSD: dh_key.c,v 1.32 2018/11/05 23:54:27 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -106,7 +106,7 @@ generate_key(DH *dh)
         unsigned l;
         BN_CTX *ctx;
         BN_MONT_CTX *mont = NULL;
-        BIGNUM *pub_key = dh->pub_key, *priv_key = dh->priv_key;
+        BIGNUM *pub_key = dh->pub_key, *priv_key = dh->priv_key, *two = NULL;
 
         if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
                 DHerror(DH_R_MODULUS_TOO_LARGE);
@@ -137,10 +137,12 @@ generate_key(DH *dh)
 
         if (generate_new_key) {
                 if (dh->q) {
-                        do {
-                                if (!BN_rand_range(priv_key, dh->q))
-                                        goto err;
-                        } while (BN_is_zero(priv_key) || BN_is_one(priv_key));
+                        if ((two = BN_new()) == NULL)
+                                goto err;
+                        if (!BN_add(two, BN_value_one(), BN_value_one()))
+                                goto err;
+                        if (!bn_rand_interval(priv_key, two, dh->q))
+                                goto err;
                 } else {
                         /* secret exponent length */
                         l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
@@ -165,6 +167,7 @@ generate_key(DH *dh)
         if (dh->priv_key == NULL)
                 BN_free(priv_key);
         BN_CTX_free(ctx);
+        BN_free(two);
         return ok;
 }