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sobelow lib sobelow dos binary_to_atom.ex
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lib/sobelow/dos/binary_to_atom.ex

defmodule Sobelow.DOS.BinToAtom do
@moduledoc """
# Denial of Service via Unsafe Atom Interpolation
In Elixir, atoms are not garbage collected. As such, if user input
is used to create atoms (as in `:"foo\#{bar}"`, or in `:erlang.binary_to_atom`),
it may result in memory exhaustion. Prefer the `String.to_existing_atom`
function for untrusted user input.
Atom interpolation checks can be ignored with the following command:
$ mix sobelow -i DOS.BinToAtom
"""
alias Sobelow.{Parse, Print}
use Sobelow.Finding
@finding_type "DOS.BinToAtom: Unsafe atom interpolation"
def run(fun, meta_file) do
severity = if meta_file.is_controller?, do: false, else: :low
{findings, params, {fun_name, [{_, line_no}]}} = parse_def(fun)
Enum.each(findings, fn {finding, var} ->
Print.add_finding(
line_no,
meta_file.filename,
fun,
fun_name,
var,
Print.get_sev(params, var, severity),
finding,
@finding_type
)
end)
end
def parse_def(fun) do
Parse.get_erlang_fun_vars_and_meta(fun, 0, :binary_to_atom, :erlang)
end
end