49 lines
1.4 KiB
Elixir
49 lines
1.4 KiB
Elixir
# https://tools.ietf.org/html/draft-cavage-http-signatures-08
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defmodule Pleroma.Web.HTTPSignatures do
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alias Pleroma.User
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def split_signature(sig) do
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default = %{"headers" => "date"}
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sig = sig
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|> String.trim()
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|> String.split(",")
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|> Enum.reduce(default, fn(part, acc) ->
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[key | rest] = String.split(part, "=")
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value = Enum.join(rest, "=")
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Map.put(acc, key, String.trim(value, "\""))
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end)
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Map.put(sig, "headers", String.split(sig["headers"], ~r/\s/))
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end
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def validate(headers, signature, public_key) do
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sigstring = build_signing_string(headers, signature["headers"])
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{:ok, sig} = Base.decode64(signature["signature"])
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:public_key.verify(sigstring, :sha256, sig, public_key)
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end
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def validate_conn(conn) do
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# TODO: How to get the right key and see if it is actually valid for that request.
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# For now, fetch the key for the actor.
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with actor_id <- conn.params["actor"],
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{:ok, public_key} <- User.get_public_key_for_ap_id(actor_id) do
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validate_conn(conn, public_key)
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else
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_ -> false
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end
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end
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def validate_conn(conn, public_key) do
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headers = Enum.into(conn.req_headers, %{})
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signature = split_signature(headers["signature"])
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validate(headers, signature, public_key)
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end
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def build_signing_string(headers, used_headers) do
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used_headers
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|> Enum.map(fn (header) -> "#{header}: #{headers[header]}" end)
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|> Enum.join("\n")
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end
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end
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