Merge bitcoin/bitcoin#25812: psbt: Avoid unsigned int overflow in PSBT_IN_TAP_BIP32_DERIVATION

70a55c0 psbt: Avoid unsigned int overflow in PSBT_IN_TAP_BIP32_DERIVATION (Andrew Chow)

Pull request description:

  Fixes #25749

ACKs for top commit:
  instagibbs:
    ACK 70a55c0
  darosior:
    re-utACK 70a55c0
  jonatack:
    Review ACK 70a55c0, this should avoid the issue reported in bitcoin/bitcoin#25749

Tree-SHA512: 6bb58e1cda9a5baa50fcd24f818b5b27ed94f0d33da3f71f6e457618176611bf2a84e1864e9a48d9303c301252bc4c1dee8b19a67dd713e849fb9442851ca341

Author: fanquake

src/psbt.h

@@ -641,6 +641,9 @@ struct PSBTInput
                     s >> leaf_hashes;
                     size_t after_hashes = s.size();
                     size_t hashes_len = before_hashes - after_hashes;
+                    if (hashes_len > value_len) {
+                        throw std::ios_base::failure("Input Taproot BIP32 keypath has an invalid length");
+                    }
                     size_t origin_len = value_len - hashes_len;
                     m_tap_bip32_paths.emplace(xonly, std::make_pair(leaf_hashes, DeserializeKeyOrigin(s, origin_len)));
                     break;

test/functional/data/rpc_psbt.json

@@ -40,6 +40,12 @@
         "cHNidP8BAF4CAAAAAZvUh2UjC/mnLmYgAflyVW5U8Mb5f+tWvLVgDYF/aZUmAQAAAAD/////AUjmBSoBAAAAIlEgAw2k/OT32yjCyylRYx4ANxOFZZf+ljiCy1AOaBEsymMAAAAAAAEBKwDyBSoBAAAAIlEgwiR++/2SrEf29AuNQtFpF1oZ+p+hDkol1/NetN2FtpJjFcFQkpt0waBJVLeLS2A16XpeB4paDyjsltVHv+6azoA6wG99YgWelJehpKJnVp2YdtpgEBr/OONSm5uTnOf5GulwEV8uSQr3zEXE94UR82BXzlxaXFYyWin7RN/CA/NW4fgAIyAssTrGgkjegGqmo2Wc88A+toIdCcgRSk6Gj+vehlu20qzAAAA=",
         "cHNidP8BAF4CAAAAAZvUh2UjC/mnLmYgAflyVW5U8Mb5f+tWvLVgDYF/aZUmAQAAAAD/////AUjmBSoBAAAAIlEgAw2k/OT32yjCyylRYx4ANxOFZZf+ljiCy1AOaBEsymMAAAAAAAEBKwDyBSoBAAAAIlEgwiR++/2SrEf29AuNQtFpF1oZ+p+hDkol1/NetN2FtpJhFcFQkpt0waBJVLeLS2A16XpeB4paDyjsltVHv+6azoA6wG99YgWelJehpKJnVp2YdtpgEBr/OONSm5uTnOf5GulwEV8uSQr3zEXE94UR82BXzlxaXFYyWin7RN/CA/NW4SMgLLE6xoJI3oBqpqNlnPPAPraCHQnIEUpOho/r3oZbttKswAAA"
     ],
+    "invalid_with_msg": [
+        [
+            "cHNidP8BAKOro2MDAwMDA5ggCAAA////CQAtAAD+///1AAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAJAAAAAAAAAAAAAAAAAAAAAAAAAD+///1Zm9ybmV3nWx1Y2vmelLmegAAAAAAAAAAAAAAAAAAAAMKAwMDAwMDAwMDAwMACvMBA3FkAAAAAAAAAAAABAAlAAAAAAAAACEWDQ0zDQ0NDQ0NDQ0NCwEAAH9/f39/fwMAAABNo6P///kAAA==",
+            "Input Taproot BIP32 keypath has an invalid length"
+        ]
+    ],
     "valid" : [
         "cHNidP8BAHUCAAAAASaBcTce3/KF6Tet7qSze3gADAVmy7OtZGQXE8pCFxv2AAAAAAD+////AtPf9QUAAAAAGXapFNDFmQPFusKGh2DpD9UhpGZap2UgiKwA4fUFAAAAABepFDVF5uM7gyxHBQ8k0+65PJwDlIvHh7MuEwAAAQD9pQEBAAAAAAECiaPHHqtNIOA3G7ukzGmPopXJRjr6Ljl/hTPMti+VZ+UBAAAAFxYAFL4Y0VKpsBIDna89p95PUzSe7LmF/////4b4qkOnHf8USIk6UwpyN+9rRgi7st0tAXHmOuxqSJC0AQAAABcWABT+Pp7xp0XpdNkCxDVZQ6vLNL1TU/////8CAMLrCwAAAAAZdqkUhc/xCX/Z4Ai7NK9wnGIZeziXikiIrHL++E4sAAAAF6kUM5cluiHv1irHU6m80GfWx6ajnQWHAkcwRAIgJxK+IuAnDzlPVoMR3HyppolwuAJf3TskAinwf4pfOiQCIAGLONfc0xTnNMkna9b7QPZzMlvEuqFEyADS8vAtsnZcASED0uFWdJQbrUqZY3LLh+GFbTZSYG2YVi/jnF6efkE/IQUCSDBFAiEA0SuFLYXc2WHS9fSrZgZU327tzHlMDDPOXMMJ/7X85Y0CIGczio4OFyXBl/saiK9Z9R5E5CVbIBZ8hoQDHAXR8lkqASECI7cr7vCWXRC+B3jv7NYfysb3mk6haTkzgHNEZPhPKrMAAAAAAAAA",
         "cHNidP8BAKACAAAAAqsJSaCMWvfEm4IS9Bfi8Vqz9cM9zxU4IagTn4d6W3vkAAAAAAD+////qwlJoIxa98SbghL0F+LxWrP1wz3PFTghqBOfh3pbe+QBAAAAAP7///8CYDvqCwAAAAAZdqkUdopAu9dAy+gdmI5x3ipNXHE5ax2IrI4kAAAAAAAAGXapFG9GILVT+glechue4O/p+gOcykWXiKwAAAAAAAEHakcwRAIgR1lmF5fAGwNrJZKJSGhiGDR9iYZLcZ4ff89X0eURZYcCIFMJ6r9Wqk2Ikf/REf3xM286KdqGbX+EhtdVRs7tr5MZASEDXNxh/HupccC1AaZGoqg7ECy0OIEhfKaC3Ibi1z+ogpIAAQEgAOH1BQAAAAAXqRQ1RebjO4MsRwUPJNPuuTycA5SLx4cBBBYAFIXRNTfy4mVAWjTbr6nj3aAfuCMIAAAA",

test/functional/rpc_psbt.py

@@ -450,6 +450,7 @@ def run_test(self):
         with open(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'data/rpc_psbt.json'), encoding='utf-8') as f:
             d = json.load(f)
             invalids = d['invalid']
+            invalid_with_msgs = d["invalid_with_msg"]
             valids = d['valid']
             creators = d['creator']
             signers = d['signer']
@@ -460,6 +461,9 @@ def run_test(self):
         # Invalid PSBTs
         for invalid in invalids:
             assert_raises_rpc_error(-22, "TX decode failed", self.nodes[0].decodepsbt, invalid)
+        for invalid in invalid_with_msgs:
+            psbt, msg = invalid
+            assert_raises_rpc_error(-22, f"TX decode failed {msg}", self.nodes[0].decodepsbt, psbt)
 
         # Valid PSBTs
         for valid in valids: