3 files changed, 44 insertions, 39 deletions

diff --git a/src/lib/libcrypto/bn/arch/amd64/bn_arch.c b/src/lib/libcrypto/bn/arch/amd64/bn_arch.c
index 55275aa14e..a377a05681 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 1.6 2023/02/22 05:46:37 jsing Exp $ */
+/*      $OpenBSD: bn_arch.c,v 1.7 2023/06/24 16:01:44 jsing Exp $ */
 /*
  * Copyright (c) 2023 Joel Sing <jsing@openbsd.org>
  *
@@ -96,9 +96,9 @@ bn_mul_comba8(BN_ULONG *rd, BN_ULONG *ad, BN_ULONG *bd)
 
 #ifdef HAVE_BN_SQR
 int
-bn_sqr(BIGNUM *r, const BIGNUM *a, int rn, BN_CTX *ctx)
+bn_sqr(BIGNUM *r, const BIGNUM *a, int r_len, BN_CTX *ctx)
 {
-        bignum_sqr(rn, (uint64_t *)r->d, a->top, (uint64_t *)a->d);
+        bignum_sqr(r_len, (uint64_t *)r->d, a->top, (uint64_t *)a->d);
 
         return 1;
 }
diff --git a/src/lib/libcrypto/bn/bn_local.h b/src/lib/libcrypto/bn/bn_local.h
index c86e4d032b..17f5447bec 100644
--- a/src/lib/libcrypto/bn/bn_local.h
+++ b/src/lib/libcrypto/bn/bn_local.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_local.h,v 1.23 2023/06/21 07:41:55 jsing Exp $ */
+/* $OpenBSD: bn_local.h,v 1.24 2023/06/24 16:01:43 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -252,7 +252,6 @@ void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb);
 void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b);
 void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b);
 
-void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp);
 void bn_sqr_comba4(BN_ULONG *r, const BN_ULONG *a);
 void bn_sqr_comba8(BN_ULONG *r, const BN_ULONG *a);
 
diff --git a/src/lib/libcrypto/bn/bn_sqr.c b/src/lib/libcrypto/bn/bn_sqr.c
index d414800feb..4eab796c90 100644
--- a/src/lib/libcrypto/bn/bn_sqr.c
+++ b/src/lib/libcrypto/bn/bn_sqr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_sqr.c,v 1.30 2023/04/19 10:51:22 jsing Exp $ */
+/* $OpenBSD: bn_sqr.c,v 1.31 2023/06/24 16:01:43 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -191,52 +191,58 @@ bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n)
 }
 #endif
 
-/* tmp must have 2*n words */
-void
-bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)
+#ifndef HAVE_BN_SQR
+static void
+bn_sqr_normal(BN_ULONG *r, int r_len, const BN_ULONG *a, int a_len,
+    BN_ULONG *tmp)
 {
-        int i, j, max;
         const BN_ULONG *ap;
         BN_ULONG *rp;
+        BN_ULONG w;
+        int n;
+
+        if (a_len <= 0)
+                return;
 
-        max = n * 2;
         ap = a;
+        w = ap[0];
+        ap++;
+
         rp = r;
-        rp[0] = rp[max - 1] = 0;
+        rp[0] = rp[r_len - 1] = 0;
         rp++;
-        j = n;
 
-        if (--j > 0) {
-                ap++;
-                rp[j] = bn_mul_words(rp, ap, j, ap[-1]);
-                rp += 2;
-        }
+        /* Compute initial product - r[n:1] = a[n:1] * a[0] */
+        n = a_len - 1;
+        rp[n] = bn_mul_words(rp, ap, n, w);
+        rp += 2;
+        n--;
 
-        for (i = n - 2; i > 0; i--) {
-                j--;
+        /* Compute and sum remaining products. */
+        while (n > 0) {
+                w = ap[0];
                 ap++;
-                rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);
+
+                rp[n] = bn_mul_add_words(rp, ap, n, w);
                 rp += 2;
+                n--;
         }
 
-        bn_add_words(r, r, r, max);
-
-        /* There will not be a carry */
-
-        bn_sqr_words(tmp, a, n);
+        /* Double the sum of products. */
+        bn_add_words(r, r, r, r_len);
 
-        bn_add_words(r, r, tmp, max);
+        /* Add squares. */
+        bn_sqr_words(tmp, a, a_len);
+        bn_add_words(r, r, tmp, r_len);
 }
 
-
 /*
  * bn_sqr() computes a * a, storing the result in r. The caller must ensure that
  * r is not the same BIGNUM as a and that r has been expanded to rn = a->top * 2
  * words.
  */
-#ifndef HAVE_BN_SQR
 int
-bn_sqr(BIGNUM *r, const BIGNUM *a, int rn, BN_CTX *ctx)
+bn_sqr(BIGNUM *r, const BIGNUM *a, int r_len, BN_CTX *ctx)
 {
         BIGNUM *tmp;
         int ret = 0;
@@ -245,10 +251,10 @@ bn_sqr(BIGNUM *r, const BIGNUM *a, int rn, BN_CTX *ctx)
 
         if ((tmp = BN_CTX_get(ctx)) == NULL)
                 goto err;
-
-        if (!bn_wexpand(tmp, rn))
+        if (!bn_wexpand(tmp, r_len))
                 goto err;
-        bn_sqr_normal(r->d, a->d, a->top, tmp->d);
+
+        bn_sqr_normal(r->d, r_len, a->d, a->top, tmp->d);
 
         ret = 1;
 
@@ -263,7 +269,7 @@ int
 BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
 {
         BIGNUM *rr;
-        int rn;
+        int r_len;
         int ret = 1;
 
         BN_CTX_start(ctx);
@@ -278,10 +284,10 @@ BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
         if (rr == NULL)
                 goto err;
 
-        rn = a->top * 2;
-        if (rn < a->top)
+        r_len = a->top * 2;
+        if (r_len < a->top)
                 goto err;
-        if (!bn_wexpand(rr, rn))
+        if (!bn_wexpand(rr, r_len))
                 goto err;
 
         if (a->top == 4) {
@@ -289,11 +295,11 @@ BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
         } else if (a->top == 8) {
                 bn_sqr_comba8(rr->d, a->d);
         } else {
-                if (!bn_sqr(rr, a, rn, ctx))
+                if (!bn_sqr(rr, a, r_len, ctx))
                         goto err;
         }
 
-        rr->top = rn;
+        rr->top = r_len;
         bn_correct_top(rr);
 
         rr->neg = 0;