1 defmodule Pleroma.Web.Salmon do
5 {doc, _rest} = :xmerl_scan.string(to_charlist(salmon))
7 {:xmlObj, :string, data} = :xmerl_xpath.string('string(//me:data[1])', doc)
8 {:xmlObj, :string, sig} = :xmerl_xpath.string('string(//me:sig[1])', doc)
9 {:xmlObj, :string, alg} = :xmerl_xpath.string('string(//me:alg[1])', doc)
10 {:xmlObj, :string, encoding} = :xmerl_xpath.string('string(//me:encoding[1])', doc)
11 {:xmlObj, :string, type} = :xmerl_xpath.string('string(//me:data[1]/@type)', doc)
14 {:ok, data} = Base.url_decode64(to_string(data), ignore: :whitespace)
15 {:ok, sig} = Base.url_decode64(to_string(sig), ignore: :whitespace)
17 encoding = to_string(encoding)
18 type = to_string(type)
20 [data, type, encoding, alg, sig]
23 def fetch_magic_key(salmon) do
24 [data, _, _, _, _] = decode(salmon)
25 {doc, _rest} = :xmerl_scan.string(to_charlist(data))
26 {:xmlObj, :string, uri} = :xmerl_xpath.string('string(//author[1]/uri)', doc)
29 base = URI.parse(uri).host
31 # TODO: Find out if this endpoint is mandated by the standard.
32 {:ok, response} = HTTPoison.get(base <> "/.well-known/webfinger", ["Accept": "application/xrd+xml"], [params: [resource: uri]])
34 {doc, _rest} = :xmerl_scan.string(to_charlist(response.body))
36 {:xmlObj, :string, magickey} = :xmerl_xpath.string('string(//Link[@rel="magic-public-key"]/@href)', doc)
37 "data:application/magic-public-key," <> magickey = to_string(magickey)
42 def decode_and_validate(magickey, salmon) do
43 [data, type, encoding, alg, sig] = decode(salmon)
45 signed_text = [data, type, encoding, alg]
46 |> Enum.map(&Base.url_encode64/1)
49 key = decode_key(magickey)
51 verify = :public_key.verify(signed_text, :sha256, sig, key)
60 def decode_key("RSA." <> magickey) do
61 make_integer = fn(bin) ->
62 list = :erlang.binary_to_list(bin)
63 Enum.reduce(list, 0, fn (el, acc) -> (acc <<< 8) ||| el end)
66 [modulus, exponent] = magickey
68 |> Enum.map(&Base.url_decode64!/1)
69 |> Enum.map(make_integer)
71 {:RSAPublicKey, modulus, exponent}
74 def encode_key({:RSAPublicKey, modulus, exponent}) do
75 modulus_enc = :binary.encode_unsigned(modulus) |> Base.url_encode64
76 exponent_enc = :binary.encode_unsigned(exponent) |> Base.url_encode64
78 "RSA.#{modulus_enc}.#{exponent_enc}"
81 def generate_rsa_pem do
82 port = Port.open({:spawn, "openssl genrsa"}, [:binary])
83 {:ok, pem} = receive do
84 {^port, {:data, pem}} -> {:ok, pem}
87 if Regex.match?(~r/RSA PRIVATE KEY/, pem) do
94 def keys_from_pem(pem) do
95 [private_key_code] = :public_key.pem_decode(pem)
96 private_key = :public_key.pem_entry_decode(private_key_code)
97 {:RSAPrivateKey, _, modulus, exponent, _, _, _, _, _, _, _} = private_key
98 public_key = {:RSAPublicKey, modulus, exponent}
99 {:ok, private_key, public_key}
102 def encode(private_key, doc) do
103 type = "application/atom+xml"
104 encoding = "base64url"
107 signed_text = [doc, type, encoding, alg]
108 |> Enum.map(&Base.url_encode64/1)
111 signature = :public_key.sign(signed_text, :sha256, private_key) |> to_string |> Base.url_encode64
112 doc_base64= doc |> Base.url_encode64
114 # Don't need proper xml building, these strings are safe to leave unescaped
116 <?xml version="1.0" encoding="UTF-8"?>
117 <me:env xmlns:me="http://salmon-protocol.org/ns/magic-env">
118 <me:data type="application/atom+xml">#{doc_base64}</me:data>
119 <me:encoding>#{encoding}</me:encoding>
120 <me:alg>#{alg}</me:alg>
121 <me:sig>#{signature}</me:sig>