forked from forks/microblog.pub
91 lines
2.7 KiB
Python
91 lines
2.7 KiB
Python
import base64
|
|
import hashlib
|
|
import typing
|
|
from datetime import datetime
|
|
|
|
import pyld # type: ignore
|
|
from Crypto.Hash import SHA256
|
|
from Crypto.Signature import PKCS1_v1_5
|
|
from loguru import logger
|
|
from pyld import jsonld # type: ignore
|
|
|
|
from app import activitypub as ap
|
|
from app.database import AsyncSession
|
|
from app.httpsig import _get_public_key
|
|
|
|
if typing.TYPE_CHECKING:
|
|
from app.key import Key
|
|
|
|
|
|
requests_loader = pyld.documentloader.requests.requests_document_loader()
|
|
|
|
|
|
def _loader(url, options={}):
|
|
# See https://github.com/digitalbazaar/pyld/issues/133
|
|
options["headers"]["Accept"] = "application/ld+json"
|
|
return requests_loader(url, options)
|
|
|
|
|
|
pyld.jsonld.set_document_loader(_loader)
|
|
|
|
|
|
def _options_hash(doc: ap.RawObject) -> str:
|
|
doc = dict(doc["signature"])
|
|
for k in ["type", "id", "signatureValue"]:
|
|
if k in doc:
|
|
del doc[k]
|
|
doc["@context"] = "https://w3id.org/identity/v1"
|
|
normalized = jsonld.normalize(
|
|
doc, {"algorithm": "URDNA2015", "format": "application/nquads"}
|
|
)
|
|
h = hashlib.new("sha256")
|
|
h.update(normalized.encode("utf-8"))
|
|
return h.hexdigest()
|
|
|
|
|
|
def _doc_hash(doc: ap.RawObject) -> str:
|
|
doc = dict(doc)
|
|
if "signature" in doc:
|
|
del doc["signature"]
|
|
normalized = jsonld.normalize(
|
|
doc, {"algorithm": "URDNA2015", "format": "application/nquads"}
|
|
)
|
|
h = hashlib.new("sha256")
|
|
h.update(normalized.encode("utf-8"))
|
|
return h.hexdigest()
|
|
|
|
|
|
async def verify_signature(
|
|
db_session: AsyncSession,
|
|
doc: ap.RawObject,
|
|
) -> bool:
|
|
if "signature" not in doc:
|
|
logger.warning("The object does contain a signature")
|
|
return False
|
|
|
|
key_id = doc["signature"]["creator"]
|
|
key = await _get_public_key(db_session, key_id)
|
|
to_be_signed = _options_hash(doc) + _doc_hash(doc)
|
|
signature = doc["signature"]["signatureValue"]
|
|
signer = PKCS1_v1_5.new(key.pubkey or key.privkey) # type: ignore
|
|
digest = SHA256.new()
|
|
digest.update(to_be_signed.encode("utf-8"))
|
|
return signer.verify(digest, base64.b64decode(signature)) # type: ignore
|
|
|
|
|
|
def generate_signature(doc: ap.RawObject, key: "Key") -> None:
|
|
options = {
|
|
"type": "RsaSignature2017",
|
|
"creator": doc["actor"] + "#main-key",
|
|
"created": datetime.utcnow().replace(microsecond=0).isoformat() + "Z",
|
|
}
|
|
doc["signature"] = options
|
|
to_be_signed = _options_hash(doc) + _doc_hash(doc)
|
|
if not key.privkey:
|
|
raise ValueError(f"missing privkey on key {key!r}")
|
|
|
|
signer = PKCS1_v1_5.new(key.privkey)
|
|
digest = SHA256.new()
|
|
digest.update(to_be_signed.encode("utf-8"))
|
|
sig = base64.b64encode(signer.sign(digest)) # type: ignore
|
|
options["signatureValue"] = sig.decode("utf-8")
|