From dd4328ae523bb375dd871e85d1bacd9311e87a89 Mon Sep 17 00:00:00 2001 From: Andrew Godwin Date: Sat, 12 Nov 2022 15:10:15 -0700 Subject: Add JSON-LD signatures and tests for sig stuff --- core/ld.py | 85 +++++++++++++++++++ core/signatures.py | 190 +++++++++++++++++++++++++++++++++++++++--- core/tests/conftest.py | 9 ++ core/tests/test_signatures.py | 156 ++++++++++++++++++++++++++++++++++ 4 files changed, 428 insertions(+), 12 deletions(-) create mode 100644 core/tests/conftest.py create mode 100644 core/tests/test_signatures.py (limited to 'core') diff --git a/core/ld.py b/core/ld.py index 8ced9ac..7863480 100644 --- a/core/ld.py +++ b/core/ld.py @@ -229,6 +229,91 @@ schemas = { } }, }, + "w3id.org/identity/v1": { + "contentType": "application/ld+json", + "documentUrl": "http://w3id.org/identity/v1", + "contextUrl": None, + "document": { + "@context": { + "id": "@id", + "type": "@type", + "cred": "https://w3id.org/credentials#", + "dc": "http://purl.org/dc/terms/", + "identity": "https://w3id.org/identity#", + "perm": "https://w3id.org/permissions#", + "ps": "https://w3id.org/payswarm#", + "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#", + "rdfs": "http://www.w3.org/2000/01/rdf-schema#", + "sec": "https://w3id.org/security#", + "schema": "http://schema.org/", + "xsd": "http://www.w3.org/2001/XMLSchema#", + "Group": "https://www.w3.org/ns/activitystreams#Group", + "claim": {"@id": "cred:claim", "@type": "@id"}, + "credential": {"@id": "cred:credential", "@type": "@id"}, + "issued": {"@id": "cred:issued", "@type": "xsd:dateTime"}, + "issuer": {"@id": "cred:issuer", "@type": "@id"}, + "recipient": {"@id": "cred:recipient", "@type": "@id"}, + "Credential": "cred:Credential", + "CryptographicKeyCredential": "cred:CryptographicKeyCredential", + "about": {"@id": "schema:about", "@type": "@id"}, + "address": {"@id": "schema:address", "@type": "@id"}, + "addressCountry": "schema:addressCountry", + "addressLocality": "schema:addressLocality", + "addressRegion": "schema:addressRegion", + "comment": "rdfs:comment", + "created": {"@id": "dc:created", "@type": "xsd:dateTime"}, + "creator": {"@id": "dc:creator", "@type": "@id"}, + "description": "schema:description", + "email": "schema:email", + "familyName": "schema:familyName", + "givenName": "schema:givenName", + "image": {"@id": "schema:image", "@type": "@id"}, + "label": "rdfs:label", + "name": "schema:name", + "postalCode": "schema:postalCode", + "streetAddress": "schema:streetAddress", + "title": "dc:title", + "url": {"@id": "schema:url", "@type": "@id"}, + "Person": "schema:Person", + "PostalAddress": "schema:PostalAddress", + "Organization": "schema:Organization", + "identityService": {"@id": "identity:identityService", "@type": "@id"}, + "idp": {"@id": "identity:idp", "@type": "@id"}, + "Identity": "identity:Identity", + "paymentProcessor": "ps:processor", + "preferences": {"@id": "ps:preferences", "@type": "@vocab"}, + "cipherAlgorithm": "sec:cipherAlgorithm", + "cipherData": "sec:cipherData", + "cipherKey": "sec:cipherKey", + "digestAlgorithm": "sec:digestAlgorithm", + "digestValue": "sec:digestValue", + "domain": "sec:domain", + "expires": {"@id": "sec:expiration", "@type": "xsd:dateTime"}, + "initializationVector": "sec:initializationVector", + "member": {"@id": "schema:member", "@type": "@id"}, + "memberOf": {"@id": "schema:memberOf", "@type": "@id"}, + "nonce": "sec:nonce", + "normalizationAlgorithm": "sec:normalizationAlgorithm", + "owner": {"@id": "sec:owner", "@type": "@id"}, + "password": "sec:password", + "privateKey": {"@id": "sec:privateKey", "@type": "@id"}, + "privateKeyPem": "sec:privateKeyPem", + "publicKey": {"@id": "sec:publicKey", "@type": "@id"}, + "publicKeyPem": "sec:publicKeyPem", + "publicKeyService": {"@id": "sec:publicKeyService", "@type": "@id"}, + "revoked": {"@id": "sec:revoked", "@type": "xsd:dateTime"}, + "signature": "sec:signature", + "signatureAlgorithm": "sec:signatureAlgorithm", + "signatureValue": "sec:signatureValue", + "CryptographicKey": "sec:Key", + "EncryptedMessage": "sec:EncryptedMessage", + "GraphSignature2012": "sec:GraphSignature2012", + "LinkedDataSignature2015": "sec:LinkedDataSignature2015", + "accessControl": {"@id": "perm:accessControl", "@type": "@id"}, + "writePermission": {"@id": "perm:writePermission", "@type": "@id"}, + } + }, + }, "*/schemas/litepub-0.1.jsonld": { "contentType": "application/ld+json", "documentUrl": "http://w3id.org/security/v1", diff --git a/core/signatures.py b/core/signatures.py index 27e7f7d..74b5324 100644 --- a/core/signatures.py +++ b/core/signatures.py @@ -1,16 +1,33 @@ import base64 import json -from typing import TYPE_CHECKING, Dict, List, Literal, TypedDict +from typing import Dict, List, Literal, TypedDict from urllib.parse import urlparse import httpx from cryptography.hazmat.primitives import hashes from django.http import HttpRequest -from django.utils.http import http_date +from django.utils import timezone +from django.utils.http import http_date, parse_http_date +from OpenSSL import crypto +from pyld import jsonld -# Prevent a circular import -if TYPE_CHECKING: - from users.models import Identity +from core.ld import format_date + + +class VerificationError(BaseException): + """ + There was an error with verifying the signature + """ + + pass + + +class VerificationFormatError(VerificationError): + """ + There was an error with the format of the signature (not if it is valid) + """ + + pass class HttpSignature: @@ -47,13 +64,13 @@ class HttpSignature: return "\n".join(f"{name.lower()}: {value}" for name, value in headers.items()) @classmethod - def parse_signature(cls, signature: str) -> "SignatureDetails": + def parse_signature(cls, signature: str) -> "HttpSignatureDetails": bits = {} for item in signature.split(","): name, value = item.split("=", 1) value = value.strip('"') bits[name.lower()] = value - signature_details: SignatureDetails = { + signature_details: HttpSignatureDetails = { "headers": bits["headers"].split(), "signature": base64.b64decode(bits["signature"]), "algorithm": bits["algorithm"], @@ -62,7 +79,7 @@ class HttpSignature: return signature_details @classmethod - def compile_signature(cls, details: "SignatureDetails") -> str: + def compile_signature(cls, details: "HttpSignatureDetails") -> str: value = f'keyId="{details["keyid"]}",headers="' value += " ".join(h.lower() for h in details["headers"]) value += '",signature="' @@ -70,12 +87,66 @@ class HttpSignature: value += f'",algorithm="{details["algorithm"]}"' return value + @classmethod + def verify_signature( + cls, + signature: bytes, + cleartext: str, + public_key: str, + ): + x509 = crypto.X509() + x509.set_pubkey( + crypto.load_publickey( + crypto.FILETYPE_PEM, + public_key.encode("ascii"), + ) + ) + try: + crypto.verify(x509, signature, cleartext.encode("ascii"), "sha256") + except crypto.Error: + raise VerificationError("Signature mismatch") + + @classmethod + def verify_request(cls, request, public_key, skip_date=False): + """ + Verifies that the request has a valid signature for its body + """ + # Verify body digest + if "HTTP_DIGEST" in request.META: + expected_digest = HttpSignature.calculate_digest(request.body) + if request.META["HTTP_DIGEST"] != expected_digest: + print("Wrong digest") + raise VerificationFormatError("Digest is incorrect") + # Verify date header + if "HTTP_DATE" in request.META and not skip_date: + header_date = parse_http_date(request.META["HTTP_DATE"]) + if abs(timezone.now().timestamp() - header_date) > 60: + print( + f"Date mismatch - they sent {header_date}, now is {timezone.now().timestamp()}" + ) + raise VerificationFormatError("Date is too far away") + # Get the signature details + if "HTTP_SIGNATURE" not in request.META: + raise VerificationFormatError("No signature header present") + signature_details = cls.parse_signature(request.META["HTTP_SIGNATURE"]) + # Reject unknown algorithms + if signature_details["algorithm"] != "rsa-sha256": + raise VerificationFormatError("Unknown signature algorithm") + # Create the signature payload + headers_string = cls.headers_from_request(request, signature_details["headers"]) + cls.verify_signature( + signature_details["signature"], + headers_string, + public_key, + ) + @classmethod async def signed_request( self, uri: str, body: Dict, - identity: "Identity", + private_key: str, + key_id: str, content_type: str = "application/json", method: Literal["post"] = "post", ): @@ -96,11 +167,20 @@ class HttpSignature: signed_string = "\n".join( f"{name.lower()}: {value}" for name, value in headers.items() ) + pkey = crypto.load_privatekey( + crypto.FILETYPE_PEM, + private_key.encode("ascii"), + ) + signature = crypto.sign( + pkey, + signed_string.encode("ascii"), + "sha256", + ) headers["Signature"] = self.compile_signature( { - "keyid": identity.key_id, + "keyid": key_id, "headers": list(headers.keys()), - "signature": identity.sign(signed_string), + "signature": signature, "algorithm": "rsa-sha256", } ) @@ -120,8 +200,94 @@ class HttpSignature: return response -class SignatureDetails(TypedDict): +class HttpSignatureDetails(TypedDict): algorithm: str headers: List[str] signature: bytes keyid: str + + +class LDSignature: + """ + Creates and verifies signatures of JSON-LD documents + """ + + @classmethod + def verify_signature(cls, document: Dict, public_key: str) -> None: + """ + Verifies a document + """ + try: + # Strip out the signature from the incoming document + signature = document.pop("signature") + # Create the options document + options = { + "@context": "https://w3id.org/identity/v1", + "creator": signature["creator"], + "created": signature["created"], + } + except KeyError: + raise VerificationFormatError("Invalid signature section") + if signature["type"].lower() != "rsasignature2017": + raise VerificationFormatError("Unknown signature type") + # Get the normalised hash of each document + final_hash = cls.normalized_hash(options) + cls.normalized_hash(document) + # Verify the signature + x509 = crypto.X509() + x509.set_pubkey( + crypto.load_publickey( + crypto.FILETYPE_PEM, + public_key.encode("ascii"), + ) + ) + try: + crypto.verify( + x509, + base64.b64decode(signature["signatureValue"]), + final_hash, + "sha256", + ) + except crypto.Error: + raise VerificationError("Signature mismatch") + + @classmethod + def create_signature( + cls, document: Dict, private_key: str, key_id: str + ) -> Dict[str, str]: + """ + Creates the signature for a document + """ + # Create the options document + options: Dict[str, str] = { + "@context": "https://w3id.org/identity/v1", + "creator": key_id, + "created": format_date(timezone.now()), + } + # Get the normalised hash of each document + final_hash = cls.normalized_hash(options) + cls.normalized_hash(document) + # Create the signature + pkey = crypto.load_privatekey( + crypto.FILETYPE_PEM, + private_key.encode("ascii"), + ) + signature = base64.b64encode(crypto.sign(pkey, final_hash, "sha256")) + # Add it to the options document along with other bits + options["signatureValue"] = signature.decode("ascii") + options["type"] = "RsaSignature2017" + return options + + @classmethod + def normalized_hash(cls, document) -> bytes: + """ + Takes a JSON-LD document and create a hash of its URDNA2015 form, + in the same way that Mastodon does internally. + + Reference: https://socialhub.activitypub.rocks/t/making-sense-of-rsasignature2017/347 + """ + norm_form = jsonld.normalize( + document, + {"algorithm": "URDNA2015", "format": "application/n-quads"}, + ) + digest = hashes.Hash(hashes.SHA256()) + digest.update(norm_form.encode("utf8")) + return digest.finalize().hex().encode("ascii") diff --git a/core/tests/conftest.py b/core/tests/conftest.py new file mode 100644 index 0000000..ab8d6ea --- /dev/null +++ b/core/tests/conftest.py @@ -0,0 +1,9 @@ +import pytest +from pyld import jsonld + +from core.ld import builtin_document_loader + + +@pytest.fixture(scope="session", autouse=True) +def ldloader(): + jsonld.set_document_loader(builtin_document_loader) diff --git a/core/tests/test_signatures.py b/core/tests/test_signatures.py new file mode 100644 index 0000000..2d480b7 --- /dev/null +++ b/core/tests/test_signatures.py @@ -0,0 +1,156 @@ +import pytest +from asgiref.sync import async_to_sync +from django.test.client import RequestFactory +from pytest_httpx import HTTPXMock + +from core.signatures import HttpSignature, LDSignature, VerificationError + +# Our testing-only keypair +private_key = """-----BEGIN PRIVATE KEY----- +MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQCzNJa9JIxQpOtQ +z8UQKXDPREF9DyBliGu3uPWo6DMnkOm7hoh2+nOryrWDqWOFaVK//n7kltHXUEbm +U3exh0/0iWfzx2AbNrI04csAvW/hRvHbHBnVTotSxzqTd3ESkpcSW4xVuz9aCcFR +kW3unSCO3fF0Lh8Jsy9N/CT6oTnwG+ZpeGvHVbh9xfR5Ww6zA7z8A6B17hbzdMd/ +3qUPijyIb5se4cWVtGg/ZJ0X1syn9u9kpwUjhHlyWH/esMRHxPuW49BPZPhhKs1+ +t//4xgZcRX515qFqPS2EtYgZAfh7M3TRv8uCSzL4TT+8ka9IUwKdV6TFaqH27bAG +KyJQfGaTAgMBAAECggEALZY5qFjlRtiFMfQApdlc5KTw4d7Yt2tqN3zaJUMYTD7d +boJNMbMJfNCetyT+d6Aw2D1ly0GglNzLhGkEQElzKfpQUt/Lj3CtCa3Mpd4K2Wxi +NwJhgfUulPqwaHYQchCPVLCsNNziw0VLA7Rymionb6B+/TaEV8PYy0ZSo90ir3UD +CL5t+IWgIPiy6pk1wGOmeB+tU4+V7/hFel+vPFNahafqVhLE311dfx2aOfweAEfN +e4JoPeJP1/fB+BVZMyVSAraKz6wheymBBNKKn/vpFsdd6it2AP4UZeFp6ma9wT9t +nk65IpHg1MBxazQd7621GrPH+ZnhMg62H/FEj6rIDQKBgQC1w1fEbk+zjI54DXU8 +FAe5cJbZS89fMP5CtzlWKzTzfdaavT+5cUYp3XAv37tSGsqYAXxY+4bHGa+qdCQO +I41cmylWGNX2e29/p2BspDPM6YQ0Z21MxFRBTWvHFrhd0bF1cXKBKPttdkKvzOEP +6uNy+/QtRNn9xF/ZjaMHcyPPTQKBgQD8ZdOmZ3TMsYJchAjjseN8S+Objw2oZzmK +6I1ULJBz3DWiyCUfir+pMjSH4fsAf9zrHkiM7xUgMByTukVRt16BrT7TlEBanAxc +/AKdNB3f0pza829LCz1lMAUn+ngZLTmRR+1rQFXqTjhB+0peJzKiMli+9BBhL9Ry +jMeTuLHdXwKBgGiz9kL5KIBNX2RYnEfXYfu4l6zktrgnCNB1q1mv2fjJbG4GxkaU +sc47+Pwa7VUGid22PWMkwSa/7SlLbdmXMT8/QjiOZfJueHQYfrsWe6B2g+mMCrJG +BiL37jXpKJsiyA7XIxaz/OG5VgDfDGaW8B60dJv/JXPBQ1WW+Wq5MM+hAoGAAUdS +xykHAnJzwpw4n06rZFnOEV+sJgo/1GBRNvfy02NuMiDpbzt4tRa4BWgzqVD8gYRp +wa0EYmFcA7OR3lQbenSyOMgre0oHFgGA0eMNs7CRctqA2dR4vyZ7IDS4nwgHnqDK +pxxwUvuKdWsceVWhgAjZQj5iRtvDK8Fi0XDCFekCgYALTU1v5iMIpaRAe+eyA2B1 +42qm4B/uhXznvOu2YXU6iJFmMgHGYgpa+Dq8uUjKtpn/LIFeX1KN0hH8z/0LW3gB +e7tN7taW0oLK3RQcEMfkZ7diE9x3LGqo/xMxsZMtxAr88p5eMEU/nxxznOqq+W9b +qxRbXYzEtHz+cW9+FZkyVw== +-----END PRIVATE KEY-----""" + +public_key = """-----BEGIN PUBLIC KEY----- +MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAszSWvSSMUKTrUM/FEClw +z0RBfQ8gZYhrt7j1qOgzJ5Dpu4aIdvpzq8q1g6ljhWlSv/5+5JbR11BG5lN3sYdP +9Iln88dgGzayNOHLAL1v4Ubx2xwZ1U6LUsc6k3dxEpKXEluMVbs/WgnBUZFt7p0g +jt3xdC4fCbMvTfwk+qE58BvmaXhrx1W4fcX0eVsOswO8/AOgde4W83THf96lD4o8 +iG+bHuHFlbRoP2SdF9bMp/bvZKcFI4R5clh/3rDER8T7luPQT2T4YSrNfrf/+MYG +XEV+deahaj0thLWIGQH4ezN00b/Lgksy+E0/vJGvSFMCnVekxWqh9u2wBisiUHxm +kwIDAQAB +-----END PUBLIC KEY-----""" + +public_key_id = "https://example.com/test-actor#test-key" + + +def test_sign_ld(): + """ + Tests signing JSON-LD documents by round-tripping them through the + verifier. + """ + # Create the signature + document = { + "id": "https://example.com/test-create", + "type": "Create", + "actor": "https://example.com/test-actor", + "object": { + "id": "https://example.com/test-object", + "type": "Note", + }, + } + signature_section = LDSignature.create_signature( + document, + private_key, + public_key_id, + ) + # Check it and assign it to the document + assert "signatureValue" in signature_section + assert signature_section["type"] == "RsaSignature2017" + document["signature"] = signature_section + # Now verify it ourselves + LDSignature.verify_signature(document, public_key) + + +def test_verifying_ld(): + """ + Tests verifying JSON-LD signatures from a known-good document + """ + document = { + "id": "https://example.com/test-create", + "type": "Create", + "actor": "https://example.com/test-actor", + "object": {"id": "https://example.com/test-object", "type": "Note"}, + "signature": { + "@context": "https://w3id.org/identity/v1", + "creator": "https://example.com/test-actor#test-key", + "created": "2022-11-12T21:41:47Z", + "signatureValue": "nTHfkHqG4hegfnjpHucXtXDLDaIKi2Duk+NeCzqTtkjf4NneXsofbZY2tGew4uAooEe1UeM23PIyjWYnR16KwcD4YY8nMj8L3xY2czwQPScMM9n+KhSHzkWfX+iI4FWKbjpPI8M53EtTRJU+1qEjjmGUx03Ip0vfvT5821etIgvY4wLNhg3y7R8fevnNux+BeytcEV6gM4awJJ6RK0xrWGLyTgDNon5V5aNUjwcV/UVPy9UAQi1KYWtA74/F0Y4oPzL5CTudPpyiViyVHZQaal4r+ExzgSvGztqKxQeT1ya6gLXxbm1YQ+8UiGVSS8zoGhMFDEZWVsRPv7e0jm5wfA==", + "type": "RsaSignature2017", + }, + } + # Ensure it verifies with correct data + LDSignature.verify_signature(document, public_key) + # Mutate it slightly and ensure it does not verify + with pytest.raises(VerificationError): + document["actor"] = "https://example.com/evil-actor" + LDSignature.verify_signature(document, public_key) + + +def test_sign_http(httpx_mock: HTTPXMock): + """ + Tests signing HTTP requests by round-tripping them through our verifier + """ + # Create document + document = { + "id": "https://example.com/test-create", + "type": "Create", + "actor": "https://example.com/test-actor", + "object": { + "id": "https://example.com/test-object", + "type": "Note", + }, + } + # Send the signed request to the mock library + httpx_mock.add_response() + async_to_sync(HttpSignature.signed_request)( + uri="https://example.com/test-actor", + body=document, + private_key=private_key, + key_id=public_key_id, + ) + # Retrieve it and construct a fake request object + outbound_request = httpx_mock.get_request() + fake_request = RequestFactory().post( + path="/test-actor", + data=outbound_request.content, + content_type=outbound_request.headers["content-type"], + HTTP_HOST="example.com", + HTTP_DATE=outbound_request.headers["date"], + HTTP_SIGNATURE=outbound_request.headers["signature"], + HTTP_DIGEST=outbound_request.headers["digest"], + ) + # Verify that + HttpSignature.verify_request(fake_request, public_key) + + +def test_verify_http(): + """ + Tests verifying HTTP requests against a known good example + """ + # Make our predictable request + fake_request = RequestFactory().post( + path="/test-actor", + data=b'{"id": "https://example.com/test-create", "type": "Create", "actor": "https://example.com/test-actor", "object": {"id": "https://example.com/test-object", "type": "Note"}}', + content_type="application/json", + HTTP_HOST="example.com", + HTTP_DATE="Sat, 12 Nov 2022 21:57:18 GMT", + HTTP_SIGNATURE='keyId="https://example.com/test-actor#test-key",headers="(request-target) host date digest content-type",signature="IRduYoDJIh90mprjUgOIdxY1iaBWHs5ou9vsDlcmSekg6DXMZTiXjmZxbNIrnpEbNFu3wTcqz1nv9H97Gp7orbYMuHm6j2ecxsvzSr37T9jxBbt3Ov3xSfuYWwhv6PuTWNxHtUQWNuAIc3wHDAQt8Flnak/uHe7swoAq4uHq2kt18iMW6CEV9XA5ESFho2HSUgRaifoNxJlIWbHYPJiP0t9aktgGBkpQoZ8ulOj3Ew4RwC1lwk9kzWiLIjU4tSAie8RbIy2g0aUvA1tQh9Uge1by3o7+349SL5iooj+B6WSCEvvjEl52wo3xoEQmv0ptYuSPLUgB9tP8q7DoHEc8Dw==",algorithm="rsa-sha256"', + HTTP_DIGEST="SHA-256=07sIbQ3GlOHWMbFMNajtPNtmUQXXu20UuvrIYLlI3kc=", + ) + # Verify that + HttpSignature.verify_request(fake_request, public_key, skip_date=True) -- cgit v1.2.3