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

4 files changed, 32 insertions, 8 deletions

diff --git a/src/lib/libcrypto/bn/bn.h b/src/lib/libcrypto/bn/bn.h
index 7d11a049d0..4ae6a8195d 100644
--- a/src/lib/libcrypto/bn/bn.h
+++ b/src/lib/libcrypto/bn/bn.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn.h,v 1.30 2016/03/04 16:06:38 doug Exp $ */
+/* $OpenBSD: bn.h,v 1.31 2016/03/04 16:23:30 deraadt Exp $ */
 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -619,10 +619,10 @@ const BIGNUM *BN_get0_nist_prime_521(void);
 
 /* library internal functions */
 
-#define bn_expand(a,bits) ((((((bits+BN_BITS2-1))/BN_BITS2)) <= (a)->dmax)?\
-        (a):bn_expand2((a),(bits+BN_BITS2-1)/BN_BITS2))
 #define bn_wexpand(a,words) (((words) <= (a)->dmax)?(a):bn_expand2((a),(words)))
 BIGNUM *bn_expand2(BIGNUM *a, int words);
+BIGNUM *bn_expand(BIGNUM *a, int bits);
+
 #ifndef OPENSSL_NO_DEPRECATED
 BIGNUM *bn_dup_expand(const BIGNUM *a, int words); /* unused */
 #endif
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)
 {
diff --git a/src/lib/libssl/src/crypto/bn/bn.h b/src/lib/libssl/src/crypto/bn/bn.h
index 7d11a049d0..4ae6a8195d 100644
--- a/src/lib/libssl/src/crypto/bn/bn.h
+++ b/src/lib/libssl/src/crypto/bn/bn.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn.h,v 1.30 2016/03/04 16:06:38 doug Exp $ */
+/* $OpenBSD: bn.h,v 1.31 2016/03/04 16:23:30 deraadt Exp $ */
 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -619,10 +619,10 @@ const BIGNUM *BN_get0_nist_prime_521(void);
 
 /* library internal functions */
 
-#define bn_expand(a,bits) ((((((bits+BN_BITS2-1))/BN_BITS2)) <= (a)->dmax)?\
-        (a):bn_expand2((a),(bits+BN_BITS2-1)/BN_BITS2))
 #define bn_wexpand(a,words) (((words) <= (a)->dmax)?(a):bn_expand2((a),(words)))
 BIGNUM *bn_expand2(BIGNUM *a, int words);
+BIGNUM *bn_expand(BIGNUM *a, int bits);
+
 #ifndef OPENSSL_NO_DEPRECATED
 BIGNUM *bn_dup_expand(const BIGNUM *a, int words); /* unused */
 #endif
diff --git a/src/lib/libssl/src/crypto/bn/bn_lib.c b/src/lib/libssl/src/crypto/bn/bn_lib.c
index 7cc76c1e85..311ec2044d 100644
--- a/src/lib/libssl/src/crypto/bn/bn_lib.c
+++ b/src/lib/libssl/src/crypto/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)
 {