Provide BN_zero()/BN_one() as functions and make BN_zero() always succeed.

BN_zero() is currently implemented using BN_set_word(), which means it can
fail, however almost nothing ever checks the return value. A long time
ago OpenSSL changed BN_zero() to always succeed and return void, however
kept BN_zero as a macro that calls a new BN_zero_ex() function, so that
it can be switched back to the "can fail" version.

Take a simpler approach - change BN_zero()/BN_one() to functions and make
BN_zero() always succeed. This will be exposed in the next bump, at which
point we can hopefully also remove the BN_zero_ex() function.

ok tb@

1 files changed, 14 insertions, 3 deletions

diff --git a/src/lib/libcrypto/bn/bn_lib.c b/src/lib/libcrypto/bn/bn_lib.c
index 851c337ef0..c47f2fa024 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 1.66 2022/11/30 03:08:39 jsing Exp $ */
+/* $OpenBSD: bn_lib.c,v 1.67 2022/12/17 15:56:25 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -998,11 +998,22 @@ BN_swap_ct(BN_ULONG condition, BIGNUM *a, BIGNUM *b, size_t nwords)
 }
 
 void
-BN_zero_ex(BIGNUM *a)
+BN_zero(BIGNUM *a)
 {
         a->neg = 0;
         a->top = 0;
-        /* XXX: a->flags &= ~BN_FIXED_TOP */
+}
+
+void
+BN_zero_ex(BIGNUM *a)
+{
+        BN_zero(a);
+}
+
+int
+BN_one(BIGNUM *a)
+{
+        return BN_set_word(a, 1);
 }
 
 int