311 lines
9.8 KiB
Elixir
311 lines
9.8 KiB
Elixir
defmodule MatrixServer.StateResolution.Authorization do
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@moduledoc """
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Implementation of Matrix event authorization rules for stat resolution.
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Note that some authorization rules are already checked in
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`MatrixServer.Event.prevalidate/1` so they are skipped here.
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"""
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import MatrixServer.StateResolution
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import Ecto.Query
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alias MatrixServer.{Repo, Event}
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alias MatrixServer.Types.UserId
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alias MatrixServer.StateResolution, as: StateRes
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@typep action :: :invite | :ban | :redact | :kick | {:event, Event.t()}
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@spec authorized?(Event.t(), StateRes.state_set()) :: boolean()
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def authorized?(%Event{type: "m.room.create", prev_events: prev_events}, %{}),
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do: prev_events == []
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# Check rule: 5.2.1
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def authorized?(
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%Event{type: "m.room.member", state_key: state_key, prev_events: [create_id]},
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%{
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{"m.room.create", ""} => %Event{event_id: create_id, content: %{"creator" => creator}}
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}
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),
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do: state_key == creator
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def authorized?(
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%Event{type: "m.room.member", sender: sender, content: %{"membership" => "join"}},
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state_set
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) do
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join_rule = get_join_rule(state_set)
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membership = get_membership(to_string(sender), state_set)
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# Check rules: 5.2.3, 5.2.4, 5.2.5
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cond do
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membership == "ban" -> false
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join_rule == "invite" -> membership in ["invite", "join"]
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join_rule == "public" -> true
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true -> false
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end
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end
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# TODO: rule 5.3.1
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def authorized?(
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%Event{
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type: "m.room.member",
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content: %{"membership" => "invite", "third_party_invite" => _}
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},
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_
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),
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do: false
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def authorized?(
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%Event{
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type: "m.room.member",
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sender: sender,
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content: %{"membership" => "invite"},
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state_key: state_key
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},
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state_set
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) do
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sender_membership = get_membership(to_string(sender), state_set)
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target_membership = get_membership(state_key, state_set)
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power_levels = get_power_levels(state_set)
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# Check rules: 5.3.2, 5.3.3, 5.3.4
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cond do
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sender_membership != "join" -> false
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target_membership in ["join", "ban"] -> false
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has_power_level?(to_string(sender), power_levels, :invite) -> true
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true -> false
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end
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end
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def authorized?(
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%Event{
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type: "m.room.member",
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sender: sender,
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content: %{"membership" => "leave"},
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state_key: state_key
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},
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state_set
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) do
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sender_membership = get_membership(to_string(sender), state_set)
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if to_string(sender) == state_key do
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# Check rule: 5.4.1
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sender_membership in ["invite", "join"]
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else
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target_membership = get_membership(state_key, state_set)
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power_levels = get_power_levels(state_set)
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sender_pl = get_user_power_level(to_string(sender), power_levels)
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target_pl = get_user_power_level(state_key, power_levels)
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# Check rules: 5.4.2, 5.4.3, 5.4.4
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cond do
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sender_membership != "join" ->
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false
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target_membership == "ban" and not has_power_level?(to_string(sender), power_levels, :ban) ->
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false
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has_power_level?(to_string(sender), power_levels, :kick) and target_pl < sender_pl ->
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true
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true ->
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false
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end
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end
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end
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def authorized?(
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%Event{
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type: "m.room.member",
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sender: sender,
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content: %{"membership" => "ban"},
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state_key: state_key
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},
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state_set
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) do
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sender_membership = get_membership(to_string(sender), state_set)
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power_levels = get_power_levels(state_set)
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sender_pl = get_user_power_level(to_string(sender), power_levels)
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target_pl = get_user_power_level(state_key, power_levels)
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# Check rules: 5.5.1, 5.5.2
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cond do
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sender_membership != "join" -> false
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has_power_level?(to_string(sender), power_levels, :ban) and target_pl < sender_pl -> true
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true -> false
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end
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end
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# Check rule: 5.6
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def authorized?(%Event{type: "m.room.member"}, _), do: false
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def authorized?(%Event{sender: sender} = event, state_set) do
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# Check rule: 6
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get_membership(to_string(sender), state_set) == "join" and _authorized?(event, state_set)
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end
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@spec _authorized?(Event.t(), StateRes.state_set()) :: boolean()
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defp _authorized?(%Event{type: "m.room.third_party_invite", sender: sender}, state_set) do
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power_levels = get_power_levels(state_set)
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# Check rule: 7.1
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has_power_level?(to_string(sender), power_levels, :invite)
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end
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defp _authorized?(%Event{state_key: state_key, sender: sender} = event, state_set) do
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power_levels = get_power_levels(state_set)
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# Check rules: 8, 9
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cond do
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not has_power_level?(to_string(sender), power_levels, {:event, event}) -> false
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String.starts_with?(state_key, "@") and state_key != sender -> false
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true -> __authorized?(event, state_set)
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end
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end
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@spec __authorized?(Event.t(), StateRes.state_set()) :: boolean()
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defp __authorized?(
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%Event{type: "m.room.power_levels", sender: sender, content: content},
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state_set
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) do
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current_pls = get_power_levels(state_set)
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new_pls = content
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sender_pl = get_user_power_level(to_string(sender), new_pls)
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# Check rules: 10.2, 10.3, 10.4, 10.5
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cond do
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not is_map_key(state_set, {"m.room.power_levels", ""}) -> true
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not authorize_power_levels(sender, sender_pl, current_pls, new_pls) -> false
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true -> true
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end
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end
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# TODO: Rule 11
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defp __authorized?(_, _), do: true
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@spec get_power_levels(StateRes.state_set()) :: map() | nil
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defp get_power_levels(state_set) do
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with %Event{content: content} <- state_set[{"m.room.power_levels", ""}] do
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content
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end
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end
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@spec get_join_rule(StateRes.state_set()) :: String.t() | nil
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defp get_join_rule(state_set) do
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with %Event{content: %{"join_rule" => join_rule}} <- state_set[{"m.room.join_rules", ""}] do
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join_rule
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end
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end
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@spec get_membership(String.t(), StateRes.state_set()) :: String.t() | nil
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defp get_membership(user, state_set) do
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with %Event{content: %{"membership" => membership}} <- state_set[{"m.room.member", user}] do
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membership
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end
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end
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@spec has_power_level?(String.t(), map() | nil, action()) :: boolean()
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defp has_power_level?(user, power_levels, action) do
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user_pl = get_user_power_level(user, power_levels)
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action_pl = get_action_power_level(action, power_levels)
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user_pl >= action_pl
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end
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@spec get_user_power_level(String.t(), map() | nil) :: non_neg_integer()
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defp get_user_power_level(user, %{"users" => users}) when is_map_key(users, user),
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do: users[user]
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defp get_user_power_level(_, %{"users_default" => pl}), do: pl
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defp get_user_power_level(_, _), do: 0
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@spec get_action_power_level(action(), map() | nil) :: non_neg_integer()
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defp get_action_power_level(:invite, %{"invite" => pl}), do: pl
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defp get_action_power_level(:invite, _), do: 50
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defp get_action_power_level(:ban, %{"ban" => pl}), do: pl
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defp get_action_power_level(:ban, _), do: 50
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# defp get_action_power_level(:redact, %{"redact" => pl}), do: pl
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# defp get_action_power_level(:redact, _), do: 50
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defp get_action_power_level(:kick, %{"kick" => pl}), do: pl
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defp get_action_power_level(:kick, _), do: 50
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defp get_action_power_level({:event, %Event{type: type}}, %{"events" => events})
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when is_map_key(events, type),
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do: events[type]
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defp get_action_power_level({:event, event}, power_levels) do
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if Event.is_state_event(event) do
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case power_levels do
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%{"state_default" => pl} -> pl
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%{} -> 50
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nil -> 0
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end
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else
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case power_levels do
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%{"events_default" => pl} -> pl
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_ -> 0
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end
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end
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end
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# TODO: Power_levels may not have all these keys defined.
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@spec authorize_power_levels(UserId.t(), non_neg_integer(), map() | nil, map() | nil) ::
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boolean()
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defp authorize_power_levels(
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user,
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user_pl,
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%{"events" => current_events, "users" => current_users} = current_pls,
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%{"events" => new_events, "users" => new_users} = new_pls
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) do
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keys = ["users_default", "events_default", "state_default", "ban", "redact", "kick", "invite"]
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valid_power_level_key_changes(Map.take(current_pls, keys), Map.take(new_pls, keys), user_pl) and
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valid_power_level_key_changes(current_events, new_events, user_pl) and
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valid_power_level_key_changes(current_users, new_users, user_pl) and
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valid_power_level_users_changes(current_users, new_users, to_string(user), user_pl)
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end
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defp authorize_power_levels(_, _, _, _), do: false
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@spec valid_power_level_key_changes(map(), map(), non_neg_integer()) :: boolean()
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defp valid_power_level_key_changes(l1, l2, user_pl) do
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set1 = MapSet.new(l1)
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set2 = MapSet.new(l2)
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MapSet.difference(
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MapSet.union(set1, set2),
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MapSet.intersection(set1, set2)
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)
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|> Enum.group_by(&elem(&1, 0), &elem(&1, 1))
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|> Enum.all?(fn {_k, values} ->
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Enum.all?(values, &(&1 <= user_pl))
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end)
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end
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defp valid_power_level_users_changes(current_users, new_users, user, user_pl) do
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set1 = MapSet.new(current_users)
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set2 = MapSet.new(new_users)
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MapSet.difference(
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MapSet.union(set1, set2),
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MapSet.intersection(set1, set2)
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)
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|> Enum.all?(fn
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{_k, values} when length(values) != 2 -> true
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{k, _} when k == user -> true
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{_k, [old_value, _]} -> old_value != user_pl
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end)
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end
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def authorized_by_auth_events?(%Event{auth_events: auth_event_ids} = event) do
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# We assume the auth events are validated beforehand.
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state_set =
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Event
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|> where([e], e.event_id in ^auth_event_ids)
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|> Repo.all()
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|> Enum.reduce(%{}, &update_state_set/2)
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IO.inspect(event)
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authorized?(event, state_set)
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end
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end
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