61 lines
2.0 KiB
Python
61 lines
2.0 KiB
Python
import base64
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from typing import List, TypedDict
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from cryptography.hazmat.primitives import hashes
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from django.http import HttpRequest
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class HttpSignature:
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"""
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Allows for calculation and verification of HTTP signatures
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"""
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@classmethod
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def calculate_digest(cls, data, algorithm="sha-256") -> str:
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"""
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Calculates the digest header value for a given HTTP body
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"""
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if algorithm == "sha-256":
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digest = hashes.Hash(hashes.SHA256())
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digest.update(data)
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return "SHA-256=" + base64.b64encode(digest.finalize()).decode("ascii")
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else:
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raise ValueError(f"Unknown digest algorithm {algorithm}")
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@classmethod
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def headers_from_request(cls, request: HttpRequest, header_names: List[str]) -> str:
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"""
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Creates the to-be-signed header payload from a Django request"""
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headers = {}
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for header_name in header_names:
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if header_name == "(request-target)":
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value = f"post {request.path}"
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elif header_name == "content-type":
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value = request.META["CONTENT_TYPE"]
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else:
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value = request.META[f"HTTP_{header_name.upper()}"]
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headers[header_name] = value
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return "\n".join(f"{name.lower()}: {value}" for name, value in headers.items())
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@classmethod
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def parse_signature(cls, signature) -> "SignatureDetails":
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bits = {}
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for item in signature.split(","):
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name, value = item.split("=", 1)
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value = value.strip('"')
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bits[name.lower()] = value
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signature_details: SignatureDetails = {
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"headers": bits["headers"].split(),
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"signature": base64.b64decode(bits["signature"]),
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"algorithm": bits["algorithm"],
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"keyid": bits["keyid"],
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}
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return signature_details
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class SignatureDetails(TypedDict):
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algorithm: str
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headers: List[str]
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signature: bytes
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keyid: str
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