128 lines
3.9 KiB
Elixir
128 lines
3.9 KiB
Elixir
defmodule Pleroma.Web.Salmon do
|
|
use Bitwise
|
|
|
|
def decode(salmon) do
|
|
{doc, _rest} = :xmerl_scan.string(to_charlist(salmon))
|
|
|
|
{:xmlObj, :string, data} = :xmerl_xpath.string('string(//me:data[1])', doc)
|
|
{:xmlObj, :string, sig} = :xmerl_xpath.string('string(//me:sig[1])', doc)
|
|
{:xmlObj, :string, alg} = :xmerl_xpath.string('string(//me:alg[1])', doc)
|
|
{:xmlObj, :string, encoding} = :xmerl_xpath.string('string(//me:encoding[1])', doc)
|
|
{:xmlObj, :string, type} = :xmerl_xpath.string('string(//me:data[1]/@type)', doc)
|
|
|
|
|
|
{:ok, data} = Base.url_decode64(to_string(data), ignore: :whitespace)
|
|
{:ok, sig} = Base.url_decode64(to_string(sig), ignore: :whitespace)
|
|
alg = to_string(alg)
|
|
encoding = to_string(encoding)
|
|
type = to_string(type)
|
|
|
|
[data, type, encoding, alg, sig]
|
|
end
|
|
|
|
def fetch_magic_key(salmon) do
|
|
[data, _, _, _, _] = decode(salmon)
|
|
{doc, _rest} = :xmerl_scan.string(to_charlist(data))
|
|
{:xmlObj, :string, uri} = :xmerl_xpath.string('string(//author[1]/uri)', doc)
|
|
|
|
uri = to_string(uri)
|
|
base = URI.parse(uri).host
|
|
|
|
# TODO: Find out if this endpoint is mandated by the standard.
|
|
{:ok, response} = HTTPoison.get(base <> "/.well-known/webfinger", ["Accept": "application/xrd+xml"], [params: [resource: uri]])
|
|
|
|
{doc, _rest} = :xmerl_scan.string(to_charlist(response.body))
|
|
|
|
{:xmlObj, :string, magickey} = :xmerl_xpath.string('string(//Link[@rel="magic-public-key"]/@href)', doc)
|
|
"data:application/magic-public-key," <> magickey = to_string(magickey)
|
|
|
|
magickey
|
|
end
|
|
|
|
def decode_and_validate(magickey, salmon) do
|
|
[data, type, encoding, alg, sig] = decode(salmon)
|
|
|
|
signed_text = [data, type, encoding, alg]
|
|
|> Enum.map(&Base.url_encode64/1)
|
|
|> Enum.join(".")
|
|
|
|
key = decode_key(magickey)
|
|
|
|
verify = :public_key.verify(signed_text, :sha256, sig, key)
|
|
|
|
if verify do
|
|
{:ok, data}
|
|
else
|
|
:error
|
|
end
|
|
end
|
|
|
|
def decode_key("RSA." <> magickey) do
|
|
make_integer = fn(bin) ->
|
|
list = :erlang.binary_to_list(bin)
|
|
Enum.reduce(list, 0, fn (el, acc) -> (acc <<< 8) ||| el end)
|
|
end
|
|
|
|
[modulus, exponent] = magickey
|
|
|> String.split(".")
|
|
|> Enum.map(&Base.url_decode64!/1)
|
|
|> Enum.map(make_integer)
|
|
|
|
{:RSAPublicKey, modulus, exponent}
|
|
end
|
|
|
|
def encode_key({:RSAPublicKey, modulus, exponent}) do
|
|
modulus_enc = :binary.encode_unsigned(modulus) |> Base.url_encode64
|
|
exponent_enc = :binary.encode_unsigned(exponent) |> Base.url_encode64
|
|
|
|
"RSA.#{modulus_enc}.#{exponent_enc}"
|
|
end
|
|
|
|
def generate_rsa_pem do
|
|
port = Port.open({:spawn, "openssl genrsa"}, [:binary])
|
|
{:ok, pem} = receive do
|
|
{^port, {:data, pem}} -> {:ok, pem}
|
|
end
|
|
Port.close(port)
|
|
if Regex.match?(~r/RSA PRIVATE KEY/, pem) do
|
|
{:ok, pem}
|
|
else
|
|
:error
|
|
end
|
|
end
|
|
|
|
def keys_from_pem(pem) do
|
|
[private_key_code] = :public_key.pem_decode(pem)
|
|
private_key = :public_key.pem_entry_decode(private_key_code)
|
|
{:RSAPrivateKey, _, modulus, exponent, _, _, _, _, _, _, _} = private_key
|
|
public_key = {:RSAPublicKey, modulus, exponent}
|
|
{:ok, private_key, public_key}
|
|
end
|
|
|
|
def encode(private_key, doc) do
|
|
type = "application/atom+xml"
|
|
encoding = "base64url"
|
|
alg = "RSA-SHA256"
|
|
|
|
signed_text = [doc, type, encoding, alg]
|
|
|> Enum.map(&Base.url_encode64/1)
|
|
|> Enum.join(".")
|
|
|
|
signature = :public_key.sign(signed_text, :sha256, private_key) |> to_string |> Base.url_encode64
|
|
doc_base64= doc |> Base.url_encode64
|
|
|
|
# Don't need proper xml building, these strings are safe to leave unescaped
|
|
salmon = """
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<me:env xmlns:me="http://salmon-protocol.org/ns/magic-env">
|
|
<me:data type="application/atom+xml">#{doc_base64}</me:data>
|
|
<me:encoding>#{encoding}</me:encoding>
|
|
<me:alg>#{alg}</me:alg>
|
|
<me:sig>#{signature}</me:sig>
|
|
</me:env>
|
|
"""
|
|
|
|
{:ok, salmon}
|
|
end
|
|
end
|