Merge #20326: tests: Fix ecdsa_verify in test framework

568a1d7 fix ecdsa verify in test framework (Stepan Snigirev)

Pull request description:

  This PR fixes a small bug in the test framework in `verify_ecdsa` function.
  `r` in ecdsa signature is modulo curve order, so if the point `R` calculated during verification has x-coordinate that is larger than the curve order, the verification will fail in the test framework but pass in libsecp256k1.

  Example (all in hex):
  public key: `0289d889551598a0263746c01e5882ccf9b7dc4ca5a37108482c9d80de40e0a8cf`
  der signature: `3006020104020104` (r = 4, s = 4)
  message: `3232323232323232323232323232323232323232323232323232323232323232`

  libsecp256k1 returns `true`, test framework returns `false`.

ACKs for top commit:
  sipa:
    utACK 568a1d7

Tree-SHA512: 9e9c58498f10085d2ad85e95caff6c92793799d2a40696ef43febcd7d313c8c3d5ecec715ca903cbb8432a8a96bd0065d86d060966d4ee651c3871ce16c252bf

test/functional/test_framework/key.py

@@ -322,7 +322,7 @@ def verify_ecdsa(self, sig, msg, low_s=True):
         u1 = z*w % SECP256K1_ORDER
         u2 = r*w % SECP256K1_ORDER
         R = SECP256K1.affine(SECP256K1.mul([(SECP256K1_G, u1), (self.p, u2)]))
-        if R is None or R[0] != r:
+        if R is None or (R[0] % SECP256K1_ORDER) != r:
             return False
         return True