Move compressed coordinate setting into public API

Now that it is method-agnostic, we can remove the method and move the
implementation to the body of the public API function. And another
method goes away. We're soon down to the ones we really need.

discussed with jsing

1 files changed, 1 insertions, 97 deletions

diff --git a/src/lib/libcrypto/ec/ecp_methods.c b/src/lib/libcrypto/ec/ecp_methods.c
index 57efce0366..66bde292a8 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 1.30 2025/01/11 14:53:46 tb Exp $ */
+/* $OpenBSD: ecp_methods.c,v 1.31 2025/01/11 15:02:42 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.
@@ -276,100 +276,6 @@ ec_point_get_affine_coordinates(const EC_GROUP *group, const EC_POINT *point,
 }
 
 static int
-ec_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
-    const BIGNUM *in_x, int y_bit, BN_CTX *ctx)
-{
-        BIGNUM *p, *a, *b, *w, *x, *y;
-        int ret = 0;
-
-        y_bit = (y_bit != 0);
-
-        BN_CTX_start(ctx);
-
-        if ((p = BN_CTX_get(ctx)) == NULL)
-                goto err;
-        if ((a = BN_CTX_get(ctx)) == NULL)
-                goto err;
-        if ((b = BN_CTX_get(ctx)) == NULL)
-                goto err;
-        if ((w = BN_CTX_get(ctx)) == NULL)
-                goto err;
-        if ((x = BN_CTX_get(ctx)) == NULL)
-                goto err;
-        if ((y = BN_CTX_get(ctx)) == NULL)
-                goto err;
-
-        /*
-         * Weierstrass equation: y^2 = x^3 + ax + b, so y is one of the
-         * square roots of x^3 + ax + b. The y-bit indicates which one.
-         */
-
-        if (!EC_GROUP_get_curve(group, p, a, b, ctx))
-                goto err;
-
-        /* XXX - should we not insist on 0 <= x < p instead? */
-        if (!BN_nnmod(x, in_x, p, ctx))
-                goto err;
-
-        /* y = x^3 */
-        if (!BN_mod_sqr(y, x, p, ctx))
-                goto err;
-        if (!BN_mod_mul(y, y, x, p, ctx))
-                goto err;
-
-        /* y += ax */
-        if (group->a_is_minus3) {
-                if (!BN_mod_lshift1_quick(w, x, p))
-                        goto err;
-                if (!BN_mod_add_quick(w, w, x, p))
-                        goto err;
-                if (!BN_mod_sub_quick(y, y, w, p))
-                        goto err;
-        } else {
-                if (!BN_mod_mul(w, a, x, p, ctx))
-                        goto err;
-                if (!BN_mod_add_quick(y, y, w, p))
-                        goto err;
-        }
-
-        /* y += b */
-        if (!BN_mod_add_quick(y, y, b, p))
-                goto err;
-
-        if (!BN_mod_sqrt(y, y, p, ctx)) {
-                ECerror(EC_R_INVALID_COMPRESSED_POINT);
-                goto err;
-        }
-
-        if (y_bit == BN_is_odd(y))
-                goto done;
-
-        if (BN_is_zero(y)) {
-                ECerror(EC_R_INVALID_COMPRESSION_BIT);
-                goto err;
-        }
-        if (!BN_usub(y, p, y))
-                goto err;
-
-        if (y_bit != BN_is_odd(y)) {
-                /* Can only happen if p is even and should not be reachable. */
-                ECerror(ERR_R_INTERNAL_ERROR);
-                goto err;
-        }
-
- done:
-        if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
-                goto err;
-
-        ret = 1;
-
- err:
-        BN_CTX_end(ctx);
-
-        return ret;
-}
-
-static int
 ec_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT **points,
     BN_CTX *ctx)
 {
@@ -1420,7 +1326,6 @@ static const EC_METHOD ec_GFp_simple_method = {
         .group_get_curve = ec_group_get_curve,
         .point_set_affine_coordinates = ec_point_set_affine_coordinates,
         .point_get_affine_coordinates = ec_point_get_affine_coordinates,
-        .point_set_compressed_coordinates = ec_set_compressed_coordinates,
         .points_make_affine = ec_points_make_affine,
         .add = ec_add,
         .dbl = ec_dbl,
@@ -1447,7 +1352,6 @@ static const EC_METHOD ec_GFp_mont_method = {
         .group_get_curve = ec_group_get_curve,
         .point_set_affine_coordinates = ec_point_set_affine_coordinates,
         .point_get_affine_coordinates = ec_point_get_affine_coordinates,
-        .point_set_compressed_coordinates = ec_set_compressed_coordinates,
         .points_make_affine = ec_points_make_affine,
         .add = ec_add,
         .dbl = ec_dbl,