Test that only paths for which a key is present are indeed signed

tests/test_sign_psbt.py

@@ -987,3 +987,44 @@ def test_sign_psbt_multiple_derivation_paths(navigator: Navigator, firmware: Fir
                               testname=test_name)
 
     assert len(result) == 2
+
+
+def test_sign_psbt_multiple_derivation_paths(navigator: Navigator, firmware: Firmware, client: RaggerClient, test_name: str):
+    # A previous implementation of the app incompletely checked the derivation paths of keys in certain
+    # transactions when multiple internal in the policy; that wasn't detected in other tests, so this
+    # was added in order to avoid regressions.
+    wallet = WalletPolicy(
+        name="Cold storage",
+        descriptor_template="wsh(or_d(multi(4,@0/<0;1>/*,@1/<0;1>/*,@2/<0;1>/*,@3/<0;1>/*),and_v(v:thresh(3,pkh(@0/<2;3>/*),a:pkh(@1/<2;3>/*),a:pkh(@2/<2;3>/*),a:pkh(@3/<2;3>/*)),older(65535))))",
+        keys_info=["[f5acc2fd/48'/1'/0'/2']tpubDFAqEGNyad35aBCKUAXbQGDjdVhNueno5ZZVEn3sQbW5ci457gLR7HyTmHBg93oourBssgUxuWz1jX5uhc1qaqFo9VsybY1J5FuedLfm4dK", 'tpubDE7NQymr4AFtewpAsWtnreyq9ghkzQBXpCZjWLFVRAvnbf7vya2eMTvT2fPapNqL8SuVvLQdbUbMfWLVDCZKnsEBqp6UK93QEzL8Ck23AwF',
+                   'tpubDF4kujkh5dAhC1pFgBToZybXdvJFXXGX4BWdDxWqP7EUpG8gxkfMQeDjGPDnTr9e4NrkFmDM1ocav3Jz6x79CRZbxGr9dzFokJLuvDDnyRh', 'tpubDD3ULTdBbyuMMMs8BCsJKgZgEnZjjbsbtV6ig3xtkQnaSc1gu9kNhmDDEW49HoLzDNA4y2TMqRzj4BugrrtcpXkjoHSoMVhJwfZLUFmv6yn']
+    )
+    wallet_hmac = bytes.fromhex(
+        "8a0e67be3697449e4d1b19d6aaec634ce747cbcf35287887588028c9da250ab3")
+
+    psbt_b64 = "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"
+    psbt = PSBT()
+    psbt.deserialize(psbt_b64)
+
+    assert len(psbt.inputs) == 1
+
+    result = client.sign_psbt(psbt, wallet, wallet_hmac, navigator,
+                              instructions=sign_psbt_instruction_approve(
+                                  firmware, has_spend_from_wallet=True, save_screenshot=False),
+                              testname=test_name)
+
+    assert len(result) == 2
+
+    # Removing all the PSBT_IN_BIP32_DERIVATION fields for that don't end in /<0;1>/*, the app should
+    # no longer sign for those keys (therefore we only expect one signature)
+    for input in psbt.inputs:
+        for pk, key_orig in list(input.hd_keypaths.items()):
+            if key_orig.path[-2] not in [0, 1]:
+                del input.hd_keypaths[pk]
+
+    result = client.sign_psbt(psbt, wallet, wallet_hmac, navigator,
+                              instructions=sign_psbt_instruction_approve(
+                                  firmware, has_spend_from_wallet=True, save_screenshot=False),
+                              testname=test_name)
+
+    assert len(result) == 1