aprs.me/lib/aprsme_web/plugs/api_csrf.ex

81 lines
2.1 KiB
Elixir

defmodule AprsmeWeb.Plugs.ApiCSRF do
@moduledoc """
CSRF protection for API endpoints using X-Requested-With header or API tokens
"""
import Phoenix.Controller
import Plug.Conn
def init(opts) do
opts
end
def call(conn, _opts) do
case get_req_header(conn, "content-type") do
[content_type | _] when content_type in ["application/json", "application/json; charset=utf-8"] ->
# For JSON requests, check for X-Requested-With header or valid API token
check_csrf_protection(conn)
_ ->
# For non-JSON requests, proceed without CSRF check
conn
end
end
defp check_csrf_protection(conn) do
case {get_req_header(conn, "x-requested-with"), get_req_header(conn, "authorization")} do
{["XMLHttpRequest"], _} ->
# Valid AJAX request
conn
{_, ["Bearer " <> _token]} ->
# Has authorization header (API token) - would need validation in production
conn
{_, _} ->
# Check for CSRF token in header
case get_req_header(conn, "x-csrf-token") do
[token] when byte_size(token) > 0 ->
# Validate CSRF token
validate_csrf_token(conn, token)
_ ->
reject_request(conn)
end
end
end
defp validate_csrf_token(conn, token) do
# Get session token for comparison
session_token = get_session(conn, "_csrf_token")
# Use Phoenix.Controller CSRF token validation
if session_token && valid_csrf_token?(conn, token) do
conn
else
reject_request(conn)
end
end
defp valid_csrf_token?(conn, token) do
session_token = get_session(conn, "_csrf_token")
if session_token do
# Use a simple comparison for now
Phoenix.Token.verify(conn, "_csrf_token", token, max_age: 86_400) == {:ok, session_token}
else
false
end
rescue
_ -> false
end
defp reject_request(conn) do
conn
|> put_status(:forbidden)
|> json(%{
error: "CSRF protection failed",
message: "Include X-Requested-With: XMLHttpRequest header or valid CSRF token"
})
|> halt()
end
end