Rework bn_add()/bn_sub() to operate on word arrays.

Rather than working on BIGNUMs, change bn_add()/bn_sub() to operate on word
arrays that potentially differ in length. This matches the behaviour of
s2n-bignum's bignum_add() and bignum_sub().

ok tb@

1 files changed, 10 insertions, 7 deletions

diff --git a/src/lib/libcrypto/bn/arch/amd64/bn_arch.c b/src/lib/libcrypto/bn/arch/amd64/bn_arch.c
index a4a2d93ada..55275aa14e 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bn_arch.c
+++ b/src/lib/libcrypto/bn/arch/amd64/bn_arch.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bn_arch.c,v 1.5 2023/02/16 11:13:05 jsing Exp $ */
+/*      $OpenBSD: bn_arch.c,v 1.6 2023/02/22 05:46:37 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -23,13 +23,15 @@
 
 #ifdef HAVE_BN_ADD
 BN_ULONG
-bn_add(BIGNUM *r, int rn, const BIGNUM *a, const BIGNUM *b)
+bn_add(BN_ULONG *r, int r_len, const BN_ULONG *a, int a_len, const BN_ULONG *b,
+    int b_len)
 {
-        return bignum_add(rn, (uint64_t *)r->d, a->top, (uint64_t *)a->d,
-            b->top, (uint64_t *)b->d);
+        return bignum_add(r_len, (uint64_t *)r, a_len, (uint64_t *)a,
+            b_len, (uint64_t *)b);
 }
 #endif
 
+
 #ifdef HAVE_BN_ADD_WORDS
 BN_ULONG
 bn_add_words(BN_ULONG *rd, const BN_ULONG *ad, const BN_ULONG *bd, int n)
@@ -41,10 +43,11 @@ bn_add_words(BN_ULONG *rd, const BN_ULONG *ad, const BN_ULONG *bd, int n)
 
 #ifdef HAVE_BN_SUB
 BN_ULONG
-bn_sub(BIGNUM *r, int rn, const BIGNUM *a, const BIGNUM *b)
+bn_sub(BN_ULONG *r, int r_len, const BN_ULONG *a, int a_len, const BN_ULONG *b,
+    int b_len)
 {
-        return bignum_sub(rn, (uint64_t *)r->d, a->top, (uint64_t *)a->d,
-            b->top, (uint64_t *)b->d);
+        return bignum_sub(r_len, (uint64_t *)r, a_len, (uint64_t *)a,
+            b_len, (uint64_t *)b);
 }
 #endif