1 files changed, 205 insertions, 1 deletions

diff --git a/src/lib/libcrypto/ec/ecp_methods.c b/src/lib/libcrypto/ec/ecp_methods.c
index 9cce6880df..f3c9f05850 100644
--- a/src/lib/libcrypto/ec/ecp_methods.c
+++ b/src/lib/libcrypto/ec/ecp_methods.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ecp_methods.c,v 1.2 2024/11/12 10:26:06 tb Exp $ */
+/* $OpenBSD: ecp_methods.c,v 1.3 2024/11/12 10:44:25 tb Exp $ */
 /* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
  * for the OpenSSL project.
  * Includes code written by Bodo Moeller for the OpenSSL project.
@@ -1608,6 +1608,160 @@ ec_GFp_simple_mul_double_nonct(const EC_GROUP *group, EC_POINT *r,
         return ec_wNAF_mul(group, r, g_scalar, 1, &point, &p_scalar, ctx);
 }
 
+static void
+ec_GFp_mont_group_clear(EC_GROUP *group)
+{
+        BN_MONT_CTX_free(group->mont_ctx);
+        group->mont_ctx = NULL;
+
+        BN_free(group->mont_one);
+        group->mont_one = NULL;
+}
+
+static int
+ec_GFp_mont_group_init(EC_GROUP *group)
+{
+        int ok;
+
+        ok = ec_GFp_simple_group_init(group);
+        group->mont_ctx = NULL;
+        group->mont_one = NULL;
+        return ok;
+}
+
+static void
+ec_GFp_mont_group_finish(EC_GROUP *group)
+{
+        ec_GFp_mont_group_clear(group);
+        ec_GFp_simple_group_finish(group);
+}
+
+static int
+ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
+{
+        ec_GFp_mont_group_clear(dest);
+
+        if (!ec_GFp_simple_group_copy(dest, src))
+                return 0;
+
+        if (src->mont_ctx != NULL) {
+                dest->mont_ctx = BN_MONT_CTX_new();
+                if (dest->mont_ctx == NULL)
+                        return 0;
+                if (!BN_MONT_CTX_copy(dest->mont_ctx, src->mont_ctx))
+                        goto err;
+        }
+        if (src->mont_one != NULL) {
+                dest->mont_one = BN_dup(src->mont_one);
+                if (dest->mont_one == NULL)
+                        goto err;
+        }
+        return 1;
+
+ err:
+        if (dest->mont_ctx != NULL) {
+                BN_MONT_CTX_free(dest->mont_ctx);
+                dest->mont_ctx = NULL;
+        }
+        return 0;
+}
+
+static int
+ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
+    const BIGNUM *b, BN_CTX *ctx)
+{
+        BN_MONT_CTX *mont = NULL;
+        BIGNUM *one = NULL;
+        int ret = 0;
+
+        ec_GFp_mont_group_clear(group);
+
+        mont = BN_MONT_CTX_new();
+        if (mont == NULL)
+                goto err;
+        if (!BN_MONT_CTX_set(mont, p, ctx)) {
+                ECerror(ERR_R_BN_LIB);
+                goto err;
+        }
+        one = BN_new();
+        if (one == NULL)
+                goto err;
+        if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
+                goto err;
+
+        group->mont_ctx = mont;
+        mont = NULL;
+        group->mont_one = one;
+        one = NULL;
+
+        ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
+        if (!ret)
+                ec_GFp_mont_group_clear(group);
+
+ err:
+        BN_MONT_CTX_free(mont);
+        BN_free(one);
+
+        return ret;
+}
+
+static int
+ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+    const BIGNUM *b, BN_CTX *ctx)
+{
+        if (group->mont_ctx == NULL) {
+                ECerror(EC_R_NOT_INITIALIZED);
+                return 0;
+        }
+        return BN_mod_mul_montgomery(r, a, b, group->mont_ctx, ctx);
+}
+
+static int
+ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+    BN_CTX *ctx)
+{
+        if (group->mont_ctx == NULL) {
+                ECerror(EC_R_NOT_INITIALIZED);
+                return 0;
+        }
+        return BN_mod_mul_montgomery(r, a, a, group->mont_ctx, ctx);
+}
+
+static int
+ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+    BN_CTX *ctx)
+{
+        if (group->mont_ctx == NULL) {
+                ECerror(EC_R_NOT_INITIALIZED);
+                return 0;
+        }
+        return BN_to_montgomery(r, a, group->mont_ctx, ctx);
+}
+
+static int
+ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+    BN_CTX *ctx)
+{
+        if (group->mont_ctx == NULL) {
+                ECerror(EC_R_NOT_INITIALIZED);
+                return 0;
+        }
+        return BN_from_montgomery(r, a, group->mont_ctx, ctx);
+}
+
+static int
+ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r, BN_CTX *ctx)
+{
+        if (group->mont_one == NULL) {
+                ECerror(EC_R_NOT_INITIALIZED);
+                return 0;
+        }
+        if (!bn_copy(r, group->mont_one))
+                return 0;
+
+        return 1;
+}
+
 static const EC_METHOD ec_GFp_simple_method = {
         .field_type = NID_X9_62_prime_field,
         .group_init = ec_GFp_simple_group_init,
@@ -1654,3 +1808,53 @@ EC_GFp_simple_method(void)
         return &ec_GFp_simple_method;
 }
 LCRYPTO_ALIAS(EC_GFp_simple_method);
+
+static const EC_METHOD ec_GFp_mont_method = {
+        .field_type = NID_X9_62_prime_field,
+        .group_init = ec_GFp_mont_group_init,
+        .group_finish = ec_GFp_mont_group_finish,
+        .group_copy = ec_GFp_mont_group_copy,
+        .group_set_curve = ec_GFp_mont_group_set_curve,
+        .group_get_curve = ec_GFp_simple_group_get_curve,
+        .group_get_degree = ec_GFp_simple_group_get_degree,
+        .group_order_bits = ec_group_simple_order_bits,
+        .group_check_discriminant = ec_GFp_simple_group_check_discriminant,
+        .point_init = ec_GFp_simple_point_init,
+        .point_finish = ec_GFp_simple_point_finish,
+        .point_copy = ec_GFp_simple_point_copy,
+        .point_set_to_infinity = ec_GFp_simple_point_set_to_infinity,
+        .point_set_Jprojective_coordinates =
+            ec_GFp_simple_set_Jprojective_coordinates,
+        .point_get_Jprojective_coordinates =
+            ec_GFp_simple_get_Jprojective_coordinates,
+        .point_set_affine_coordinates =
+            ec_GFp_simple_point_set_affine_coordinates,
+        .point_get_affine_coordinates =
+            ec_GFp_simple_point_get_affine_coordinates,
+        .point_set_compressed_coordinates =
+            ec_GFp_simple_set_compressed_coordinates,
+        .add = ec_GFp_simple_add,
+        .dbl = ec_GFp_simple_dbl,
+        .invert = ec_GFp_simple_invert,
+        .is_at_infinity = ec_GFp_simple_is_at_infinity,
+        .is_on_curve = ec_GFp_simple_is_on_curve,
+        .point_cmp = ec_GFp_simple_cmp,
+        .make_affine = ec_GFp_simple_make_affine,
+        .points_make_affine = ec_GFp_simple_points_make_affine,
+        .mul_generator_ct = ec_GFp_simple_mul_generator_ct,
+        .mul_single_ct = ec_GFp_simple_mul_single_ct,
+        .mul_double_nonct = ec_GFp_simple_mul_double_nonct,
+        .field_mul = ec_GFp_mont_field_mul,
+        .field_sqr = ec_GFp_mont_field_sqr,
+        .field_encode = ec_GFp_mont_field_encode,
+        .field_decode = ec_GFp_mont_field_decode,
+        .field_set_to_one = ec_GFp_mont_field_set_to_one,
+        .blind_coordinates = ec_GFp_simple_blind_coordinates,
+};
+
+const EC_METHOD *
+EC_GFp_mont_method(void)
+{
+        return &ec_GFp_mont_method;
+}
+LCRYPTO_ALIAS(EC_GFp_mont_method);