revert use of bn_rand_interval due to failures with ECDHE and TLS

2 files changed, 17 insertions, 8 deletions

diff --git a/src/lib/libcrypto/dsa/dsa_key.c b/src/lib/libcrypto/dsa/dsa_key.c
index 7ead1f30cc..4039fbf407 100644
--- a/src/lib/libcrypto/dsa/dsa_key.c
+++ b/src/lib/libcrypto/dsa/dsa_key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dsa_key.c,v 1.26 2018/11/05 23:54:27 tb Exp $ */
+/* $OpenBSD: dsa_key.c,v 1.27 2018/11/06 02:14:39 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -92,8 +92,10 @@ dsa_builtin_keygen(DSA *dsa)
                         goto err;
         }
 
-        if (!bn_rand_interval(priv_key, BN_value_one(), dsa->q))
-                goto err;
+        do {
+                if (!BN_rand_range(priv_key, dsa->q))
+                        goto err;
+        } while (BN_is_zero(priv_key));
 
         if (pub_key == NULL) {
                 if ((pub_key = BN_new()) == NULL)
diff --git a/src/lib/libcrypto/dsa/dsa_ossl.c b/src/lib/libcrypto/dsa/dsa_ossl.c
index cda750a0ed..6eb391ddeb 100644
--- a/src/lib/libcrypto/dsa/dsa_ossl.c
+++ b/src/lib/libcrypto/dsa/dsa_ossl.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dsa_ossl.c,v 1.38 2018/11/05 23:54:27 tb Exp $ */
+/* $OpenBSD: dsa_ossl.c,v 1.39 2018/11/06 02:14:39 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -150,9 +150,13 @@ dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
          *
          *  s = inv(k)inv(b)(bm + bxr) mod q
          *
-         * Where b is a random value in the range [1, q).
+         * Where b is a random value in the range [1, q-1].
          */
-        if (!bn_rand_interval(&b, BN_value_one(), dsa->q))
+        if (!BN_sub(&bm, dsa->q, BN_value_one()))
+                goto err;
+        if (!BN_rand_range(&b, &bm))
+                goto err;
+        if (!BN_add(&b, &b, BN_value_one()))
                 goto err;
         if (BN_mod_inverse_ct(&binv, &b, dsa->q, ctx) == NULL)
                 goto err;
@@ -238,8 +242,11 @@ dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
             !BN_set_bit(&m, q_bits))
                 goto err;
 
-        if (!bn_rand_interval(&k, BN_value_one(), dsa->q))
-                goto err;
+        /* Get random k */
+        do {
+                if (!BN_rand_range(&k, dsa->q))
+                        goto err;
+        } while (BN_is_zero(&k));
 
         BN_set_flags(&k, BN_FLG_CONSTTIME);