validate pubkey from extended public key when parsed; validate extended key version

ngu/hdnode.c

@@ -261,18 +261,29 @@ STATIC mp_obj_t s_hdnode_deserialize(mp_obj_t self_in, mp_obj_t encoded) {
     p += 32;
 
     if(p[0] == 0x00) {
+        /* mainnet/testnet private */
+        assert((version == 0x0488ADE4) || (version == 0x04358394));
         p++;
         memcpy(self->privkey, p, 32);
         p += 32;
         self->have_private = true;
         _calc_pubkey(self);
     } else if(p[0] == 0x02 || p[0] == 0x3) {
+        /* mainnet/testnet public */
+        assert((version == 0x0488B21E) || (version == 0x043587CF));
         // 33 bytes of pubkey
         self->have_private = false;
         memcpy(self->pubkey, p, 33);
         p += 33;
+
+        /* verify that parsed pubkey is valid */
+        secp256k1_pubkey pub;
+        int ok;
+        ok = secp256k1_ec_pubkey_parse(lib_ctx, &pub, self->pubkey, 33);
+        if(!ok) goto fail;
+
     } else {
-        mp_raise_ValueError(MP_ERROR_TEXT("bad pubkey"));
+        goto fail;
     }
 
     _calc_hash160(self);
@@ -291,6 +302,11 @@ STATIC mp_obj_t s_hdnode_deserialize(mp_obj_t self_in, mp_obj_t encoded) {
     assert(p == &tmp[78]);
 
     return mp_obj_new_int(version);
+
+    fail:
+        self->depth = -1;
+        mp_raise_ValueError(MP_ERROR_TEXT("bad pubkey"));
+        return 0;       // not reached
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(s_hdnode_deserialize_obj, s_hdnode_deserialize);
 

ngu/ngu_tests/Makefile

@@ -25,6 +25,7 @@ test tests:
 	$(MPY) test_ec_gen.py
 	$(PY) test_bip39.py
 	$(MPY) test_bip39.py
+ 	$(MPY) test_bip32.py
 
 # runs the test compiled in, not here
 # or, on target

ngu/ngu_tests/run.py

@@ -23,3 +23,4 @@
     import ngu_tests.test_ec
     import ngu_tests.test_ec_gen
 import ngu_tests.test_bip39
+import ngu_tests.test_bip32

ngu/ngu_tests/test_bip32.py

@@ -0,0 +1,35 @@
+# Invalid Extended Keys test
+# https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#test-vector-5
+import ngu
+
+TO_DO = [
+    "xpub661MyMwAqRbcEYS8w7XLSVeEsBXy79zSzH1J8vCdxAZningWLdN3zgtU6LBpB85b3D2yc8sfvZU521AAwdZafEz7mnzBBsz4wKY5fTtTQBm", #(pubkey version / prvkey mismatch)
+    "xpub661MyMwAqRbcEYS8w7XLSVeEsBXy79zSzH1J8vCdxAZningWLdN3zgtU6Txnt3siSujt9RCVYsx4qHZGc62TG4McvMGcAUjeuwZdduYEvFn", #(invalid pubkey prefix 04)
+    "xpub661MyMwAqRbcEYS8w7XLSVeEsBXy79zSzH1J8vCdxAZningWLdN3zgtU6N8ZMMXctdiCjxTNq964yKkwrkBJJwpzZS4HS2fxvyYUA4q2Xe4", #(invalid pubkey prefix 01)
+    # allowed
+    # "xpub661no6RGEX3uJkY4bNnPcw4URcQTrSibUZ4NqJEw5eBkv7ovTwgiT91XX27VbEXGENhYRCf7hyEbWrR3FewATdCEebj6znwMfQkhRYHRLpJ", # (zero depth with non - zero parent fingerprint)
+    # "xpub661MyMwAuDcm6CRQ5N4qiHKrJ39Xe1R1NyfouMKTTWcguwVcfrZJaNvhpebzGerh7gucBvzEQWRugZDuDXjNDRmXzSZe4c7mnTK97pTvGS8", # (zero depth with non - zero index)
+    "xpub661MyMwAqRbcEYS8w7XLSVeEsBXy79zSzH1J8vCdxAZningWLdN3zgtU6Q5JXayek4PRsn35jii4veMimro1xefsM58PgBMrvdYre8QyULY", # (invalid pubkey 020000000000000000000000000000000000000000000000000000000000000007)
+    "DMwo58pR1QLEFihHiXPVykYB6fJmsTeHvyTp7hRThAtCX8CvYzgPcn8XnmdfHPmHJiEDXkTiJTVV9rHEBUem2mwVbbNfvT2MTcAqj3nesx8uBf9", # unknown version
+    # private below
+    "xprv9s21ZrQH143K24Mfq5zL5MhWK9hUhhGbd45hLXo2Pq2oqzMMo63oStZzFGTQQD3dC4H2D5GBj7vWvSQaaBv5cxi9gafk7NF3pnBju6dwKvH", # (prvkey version / pubkey mismatch)
+    "xprv9s21ZrQH143K24Mfq5zL5MhWK9hUhhGbd45hLXo2Pq2oqzMMo63oStZzFGpWnsj83BHtEy5Zt8CcDr1UiRXuWCmTQLxEK9vbz5gPstX92JQ", # (invalid prvkey prefix 04)
+    "xprv9s21ZrQH143K24Mfq5zL5MhWK9hUhhGbd45hLXo2Pq2oqzMMo63oStZzFAzHGBP2UuGCqWLTAPLcMtD9y5gkZ6Eq3Rjuahrv17fEQ3Qen6J", # (invalid prvkey prefix 01)
+    # allowed
+    # "xprv9s2SPatNQ9Vc6GTbVMFPFo7jsaZySyzk7L8n2uqKXJen3KUmvQNTuLh3fhZMBoG3G4ZW1N2kZuHEPY53qmbZzCHshoQnNf4GvELZfqTUrcv", # (zero depth with non - zero parent fingerprint)
+    # "xprv9s21ZrQH4r4TsiLvyLXqM9P7k1K3EYhA1kkD6xuquB5i39AU8KF42acDyL3qsDbU9NmZn6MsGSUYZEsuoePmjzsB3eFKSUEh3Gu1N3cqVUN", # (zero depth with non - zero index)
+    "xprv9s21ZrQH143K24Mfq5zL5MhWK9hUhhGbd45hLXo2Pq2oqzMMo63oStZzF93Y5wvzdUayhgkkFoicQZcP3y52uPPxFnfoLZB21Teqt1VvEHx", # (private key 0 not in 1..n - 1)
+    "xprv9s21ZrQH143K24Mfq5zL5MhWK9hUhhGbd45hLXo2Pq2oqzMMo63oStZzFAzHGBP2UuGCqWLTAPLcMtD5SDKr24z3aiUvKr9bJpdrcLg1y3G", # (private key n not in 1..n - 1)
+    "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHL", # (invalid checksum)
+    "DMwo58pR1QLEFihHiXPVykYB6fJmsTeHvyTp7hRThAtCX8CvYzgPcn8XnmdfHGMQzT7ayAmfo4z3gY5KfbrZWZ6St24UVf2Qgo6oujFktLHdHY4", # (unknown version)
+]
+
+HDNode = ngu.hdnode.HDNode
+for ek in TO_DO:
+    n = HDNode()
+    try:
+        n.deserialize(ek)
+        raise AttributeError
+    except (AssertionError, ValueError, RuntimeError): pass
+
+print('PASS - test_bip32')

ngu/ngu_tests/test_hdnode.py

@@ -85,7 +85,7 @@ def test_derive():
     p1 = a.derive(43, False).pubkey()
 
     b = HDNode()
-    assert b.deserialize(a.serialize(0x123, 0)) == 0x123
+    assert b.deserialize(a.serialize(0x0488B21E, 0)) == 0x0488B21E
     p2 = b.pubkey()
     assert b.depth() == 1
     assert b.parent_fp() == m_fp