pleroma

commit: d0f7a5c4f53f631703cc108b95c52a934c122873
parent 1062185ba03ffa03f0dfcfc11f948285b2ffd610
Author: Haelwenn <contact+git.pleroma.social@hacktivis.me>
Date:   Sat,  5 Aug 2023 08:13:03 +0000

Merge branch 'mergeback/2.5.4' into 'develop'

Mergeback: 2.5.4

See merge request pleroma/pleroma!3930
Diffstat:
M
CHANGELOG.md
5
+++++
A
changelog.d/akkoma-xml-remote-entities.security
1
+
M
lib/pleroma/web/xml.ex
5
++++-
M
mix.exs
2
+-
A
test/fixtures/xml_external_entities.xml
3
+++
M
test/pleroma/web/web_finger_test.exs
23
+++++++++++++++++++++++
A
test/pleroma/web/xml_test.exs
10
++++++++++

7 files changed, 47 insertions(+), 2 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -18,6 +18,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Removed
 - BREAKING: Support for passwords generated with `crypt(3)` (Gnu Social migration artifact)
 
+## 2.5.4
+
+## Security
+- Fix XML External Entity (XXE) loading vulnerability allowing to fetch arbitary files from the server's filesystem
+
 ## 2.5.3
 
 ### Security
diff --git a/changelog.d/akkoma-xml-remote-entities.security b/changelog.d/akkoma-xml-remote-entities.security
@@ -0,0 +1 @@
+Fix XML External Entity (XXE) loading vulnerability allowing to fetch arbitary files from the server's filesystem
diff --git a/lib/pleroma/web/xml.ex b/lib/pleroma/web/xml.ex
@@ -29,7 +29,10 @@ defmodule Pleroma.Web.XML do
       {doc, _rest} =
         text
         |> :binary.bin_to_list()
-        |> :xmerl_scan.string(quiet: true)
+        |> :xmerl_scan.string(
+          quiet: true,
+          fetch_fun: fn _, _ -> raise "Resolving external entities not supported" end
+        )
 
       {:ok, doc}
     rescue
diff --git a/mix.exs b/mix.exs
@@ -4,7 +4,7 @@ defmodule Pleroma.Mixfile do
   def project do
     [
       app: :pleroma,
-      version: version("2.5.53"),
+      version: version("2.5.54"),
       elixir: "~> 1.11",
       elixirc_paths: elixirc_paths(Mix.env()),
       compilers: [:phoenix] ++ Mix.compilers(),
diff --git a/test/fixtures/xml_external_entities.xml b/test/fixtures/xml_external_entities.xml
@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file:///etc/passwd"> ]>
+<stockCheck><productId>&xxe;</productId></stockCheck>
diff --git a/test/pleroma/web/web_finger_test.exs b/test/pleroma/web/web_finger_test.exs
@@ -180,5 +180,28 @@ defmodule Pleroma.Web.WebFingerTest do
 
       {:ok, _data} = WebFinger.finger("pekorino@pawoo.net")
     end
+
+    test "refuses to process XML remote entities" do
+      Tesla.Mock.mock(fn
+        %{
+          url: "https://pawoo.net/.well-known/webfinger?resource=acct:pekorino@pawoo.net"
+        } ->
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: File.read!("test/fixtures/xml_external_entities.xml"),
+             headers: [{"content-type", "application/xrd+xml"}]
+           }}
+
+        %{url: "https://pawoo.net/.well-known/host-meta"} ->
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: File.read!("test/fixtures/tesla_mock/pawoo.net_host_meta")
+           }}
+      end)
+
+      assert :error = WebFinger.finger("pekorino@pawoo.net")
+    end
   end
 end
diff --git a/test/pleroma/web/xml_test.exs b/test/pleroma/web/xml_test.exs
@@ -0,0 +1,10 @@
+defmodule Pleroma.Web.XMLTest do
+  use Pleroma.DataCase, async: true
+
+  alias Pleroma.Web.XML
+
+  test "refuses to load external entities from XML" do
+    data = File.read!("test/fixtures/xml_external_entities.xml")
+    assert(:error == XML.parse_document(data))
+  end
+end