graduate bn_expand() to a real function. the openssl version of this

uses a macro with multiple-evaluations of arguments (different amount
than the previous version..), but doug/bcook's inline version makes
BIGNUM not opaque [problem spotted by naddy]
ok doug

1 files changed, 13 insertions, 1 deletions

diff --git a/src/lib/libcrypto/bn/bn_lib.c b/src/lib/libcrypto/bn/bn_lib.c
index 7cc76c1e85..311ec2044d 100644
--- a/src/lib/libcrypto/bn/bn_lib.c
+++ b/src/lib/libcrypto/bn/bn_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_lib.c,v 1.34 2015/09/10 15:56:25 jsing Exp $ */
+/* $OpenBSD: bn_lib.c,v 1.35 2016/03/04 16:23:30 deraadt Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -550,6 +550,18 @@ BN_get_word(const BIGNUM *a)
         return 0;
 }
 
+BIGNUM *
+bn_expand(BIGNUM *a, int bits)
+{
+        if (bits > (INT_MAX - BN_BITS2 + 1))
+                return (NULL);
+
+        if (((bits + BN_BITS2 - 1) / BN_BITS2) <= a->dmax)
+                return (a);
+
+        return bn_expand2(a, (bits + BN_BITS2 - 1) / BN_BITS2);
+}
+
 int
 BN_set_word(BIGNUM *a, BN_ULONG w)
 {