feat(tests): add test cases for P256 input hash special values (#2203)

Make sure a valid P256 signature is correctly verified in the full range
of hash values: `0–2**256-1`. Add also tests with invalid signature but
with valid inputs (r and s in range, Q on curve).

Author: chfast

tests/osaka/eip7951_p256verify_precompiles/spec.py

@@ -99,6 +99,9 @@ class Spec:
     B = 0x5AC635D8AA3A93E7B3EBBD55769886BC651D06B0CC53B0F63BCE3C3E27D2604B  ## Curve Coefficient
     N = 0xFFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551  ## Subgroup Order
 
+    Gx = 0x6B17D1F2E12C4247F8BCE6E563A440F277037D812DEB33A0F4A13945D898C296  ## Generator Point X
+    Gy = 0x4FE342E2FE1A7F9B8EE7EB4A7C0F9E162BCE33576B315ECECBB6406837BF51F5  ## Generator Point Y
+
     # Other constants
     SUCCESS_RETURN_VALUE = b"\x01".rjust(32, b"\x00")
     INVALID_RETURN_VALUE = b""

tests/osaka/eip7951_p256verify_precompiles/test_p256verify.py

@@ -89,6 +89,50 @@ def test_wycheproof_extra(state_test: StateTestFiller, pre: Alloc, post: dict, t
     state_test(env=Environment(), pre=pre, post=post, tx=tx)
 
 
+@pytest.mark.parametrize(
+    "input_data",
+    [
+        pytest.param(
+            H(0) + R(Spec.Gx) + S(Spec.Gx) + X(Spec.Gx) + Y(Spec.Gy),
+            id="hash_0",
+        ),
+        pytest.param(
+            H(Spec.N - 1) + R(Spec.Gx) + S(Spec.Gx - 1) + X(Spec.Gx) + Y(Spec.Gy),
+            id="hash_N_minus_1",
+        ),
+        pytest.param(
+            H(Spec.N) + R(Spec.Gx) + S(Spec.Gx) + X(Spec.Gx) + Y(Spec.Gy),
+            id="hash_N",
+        ),
+        pytest.param(
+            H(Spec.P - 1)
+            + R(Spec.Gx)
+            + S(Spec.Gx + Spec.P - 1 - Spec.N)
+            + X(Spec.Gx)
+            + Y(Spec.Gy),
+            id="hash_P_minus_1",
+        ),
+        pytest.param(
+            H(Spec.P) + R(Spec.Gx) + S(Spec.Gx + Spec.P - Spec.N) + X(Spec.Gx) + Y(Spec.Gy),
+            id="hash_P",
+        ),
+        pytest.param(
+            H(2**256 - 1)
+            + R(Spec.Gx)
+            + S(Spec.Gx + 2**256 - 1 - Spec.N)
+            + X(Spec.Gx)
+            + Y(Spec.Gy),
+            id="hash_max",
+        ),
+    ],
+)
+@pytest.mark.parametrize("expected_output", [Spec.SUCCESS_RETURN_VALUE], ids=[""])
+@pytest.mark.parametrize("precompile_address", [Spec.P256VERIFY], ids=[""])
+def test_valid(state_test: StateTestFiller, pre: Alloc, post: dict, tx: Transaction):
+    """Positive tests for the P256VERIFY precompile."""
+    state_test(env=Environment(), pre=pre, post=post, tx=tx)
+
+
 @pytest.mark.parametrize(
     "input_data",
     [
@@ -105,6 +149,30 @@ def test_wycheproof_extra(state_test: StateTestFiller, pre: Alloc, post: dict, t
             H(0) + R(0) + S(0) + X(0) + Y(0),
             id="input_all_zeros",
         ),
+        pytest.param(
+            H(0) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_0",
+        ),
+        pytest.param(
+            H(Spec.N - 1) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_N_minus_1",
+        ),
+        pytest.param(
+            H(Spec.N) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_N",
+        ),
+        pytest.param(
+            H(Spec.P - 1) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_P_minus_1",
+        ),
+        pytest.param(
+            H(Spec.P) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_P",
+        ),
+        pytest.param(
+            H(2**256 - 1) + Spec.R0 + Spec.S0 + Spec.X0 + Spec.Y0,
+            id="hash_max",
+        ),
         pytest.param(
             Spec.H0 + R(0) + Spec.S0 + Spec.X0 + Spec.Y0,
             id="r_eq_to_zero",