funga

commit 89144945bba731dbdfc85554c211a4141b72266d
parent 88c01e7edfae7bf4e2d4687ca521ab3778ba0528
Author: lash <dev@holbrook.no>
Date:   Fri, 23 Jun 2023 21:31:22 +0100

Verify sig from xml curve params

Diffstat:
M
funga/xml/xml.py
 | 
27
+++++++++++++++++++++++----
M
test_requirements.txt
 | 
1
+
M
tests/test_xml.py
 | 
35
++++++++++++++++++++++++++++++++++-
M
tests/testdata/sign.xml
 | 
4
++--

4 files changed, 60 insertions(+), 7 deletions(-)
diff --git a/funga/xml/xml.py b/funga/xml/xml.py
@@ -20,6 +20,15 @@ def cryptobinary_to_int(v):
     return int.from_bytes(b, byteorder='big')
 
 
+def cryptobinary_to_pair(v):
+    b = b64decode(v)
+    b = b[1:] # TODO: force uncompressed
+    l = int(len(b) / 2)
+    x = int.from_bytes(b[:l], byteorder='big')
+    y = int.from_bytes(b[l:], byteorder='big')
+    return (x, y,)
+
+
 class SignatureParser:
 
     namespaces = {
@@ -62,18 +71,24 @@ class SignatureParser:
 
 
     def clear(self):
-        self.signature = None
+        self.sig_r = None
+        self.sig_s = None
+        self.sig_v = None
         self.digest = None
         self.public_key = None
         self.prime = None
         self.curve_a = None
         self.curve_b = None
-        self.base = None
+        self.base_x = None
+        self.base_y = None
         self.order = None
         self.cofactor = None
         self.keyname = None
 
 
+    def __str__(self):
+        return 'order {}'.format(self.order)
+
     def set(self, k, v):
         if k.__class__.__name__ == 'SignatureAccept':
             self.__settings[k.value - 1].append(v)
@@ -124,7 +139,11 @@ class SignatureParser:
         m = self.get(SignatureVerify.SIGNATURE)
         if m != None:
             assert m(b)
-        self.signature = b
+        #self.signature = b
+        logg.debug('sig {}'.format(b.hex()))
+        self.sig_r = int.from_bytes(b[:32], byteorder='little')
+        self.sig_s = int.from_bytes(b[32:64], byteorder='little')
+        self.sig_v = int(b[64])
 
     def __opt_verify_signedinfo(self, el):
         r = el.find('./DigestMethod', namespaces=self.namespaces)
@@ -164,7 +183,7 @@ class SignatureParser:
         r = el.find('./dsig11:ECParameters/dsig11:Curve/dsig11:B', namespaces=self.namespaces)
         self.curve_b = cryptobinary_to_int(r.text)
         r = el.find('./dsig11:ECParameters/dsig11:Base', namespaces=self.namespaces)
-        self.base = cryptobinary_to_int(r.text)
+        (self.base_x, self.base_y) = cryptobinary_to_pair(r.text)
         r = el.find('./dsig11:ECParameters/dsig11:Order', namespaces=self.namespaces)
         self.order = cryptobinary_to_int(r.text)
         r = el.find('./dsig11:ECParameters/dsig11:CoFactor', namespaces=self.namespaces)
diff --git a/test_requirements.txt b/test_requirements.txt
@@ -0,0 +1 @@
+fastecdsa~=2.3.0
diff --git a/tests/test_xml.py b/tests/test_xml.py
@@ -4,6 +4,10 @@ import unittest
 import os
 from base64 import b64decode
 
+# external imports
+from fastecdsa import curve
+from fastecdsa import ecdsa
+
 # local imports
 from funga.xml import SignatureParser
 from funga.xml import SignatureAccept
@@ -73,10 +77,39 @@ class TestXmlSig(unittest.TestCase):
         self.parser.set(SignatureVerify.PUBLICKEY, verify_pub_ok)
         self.parser.process_file(self.xml_file)
 
-        self.assertEqual(self.parser.signature.hex(), 'af77767edbccdf46380fed6f06af43c807de4bedce2eda129923340e9577c97e76bc55d587103a367057167f351ae1cfd6b8dea6e0282257de3594fbe3d8780700')
+        #self.assertEqual(self.parser.signature.hex(), 'af77767edbccdf46380fed6f06af43c807de4bedce2eda129923340e9577c97e76bc55d587103a367057167f351ae1cfd6b8dea6e0282257de3594fbe3d8780700')
         self.assertEqual(self.parser.public_key.hex(), '049f6bb6a7e3f5b7ee71756a891233d1415658f8712bac740282e083dc9240f5368bdb3b256a5bf40a8f7f9753414cb447ee3f796c5f30f7eb40a7f5018fc7f02e')
         self.assertEqual(self.parser.digest.hex(), '76b2e96714d3b5e6eb1d1c509265430b907b44f72b2a22b06fcd4d96372b8565')
 
+        logg.debug('r {}'.format(self.parser))
+
+        c = curve.Curve(
+                'eth',
+                self.parser.prime,
+                self.parser.curve_a,
+                self.parser.curve_b,
+                self.parser.order,
+                self.parser.base_x,
+                self.parser.base_y,
+                )
+
+        class Pubk:
+            def __init__(self, x, y):
+                self.x = x
+                self.y = y
+
+        x = int.from_bytes(self.parser.public_key[1:33], byteorder='big')
+        y = int.from_bytes(self.parser.public_key[33:65], byteorder='big')
+        pubk = Pubk(x, y)
+
+        ecdsa.verify(
+                (self.parser.sig_r, self.parser.sig_s),
+                self.parser.digest,
+                pubk,
+                curve=c,
+                )
+
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/testdata/sign.xml b/tests/testdata/sign.xml
@@ -26,8 +26,8 @@
 					</Prime>
 				</FieldID>
 				<Curve>
-					<A>AAo=</A>
-					<B>Bwo=</B>
+					<A>AA==</A>
+					<B>Bw==</B>
 				</Curve>
 				<Base>BHm+Zn753LusVaBilc6HCwcCm/zbLc4o2VnygVsW+BeYSDradyajxGVdpPv8DhEIqP0XtEimhVQZnEfQj/sQ1Lg=</Base>
 				<Order>/////////////////////rqu3OavSKA7v9JejNA2QUE=</Order>