Merge remote-tracking branch 'upstream/develop' into spc2

changelog.d/fix-webfinger-spoofing.security

@@ -0,0 +1 @@
+Fix webfinger spoofing.

changelog.d/webfinger-validation.fix

@@ -0,0 +1 @@
+Fix validate_webfinger when running a different domain for Webfinger

lib/pleroma/application.ex

@@ -162,7 +162,8 @@ defp cachex_children do
         expiration: chat_message_id_idempotency_key_expiration(),
         limit: 500_000
       ),
-      build_cachex("rel_me", limit: 2500)
+      build_cachex("rel_me", limit: 2500),
+      build_cachex("host_meta", default_ttl: :timer.minutes(120), limit: 5000)
     ]
   end
 

lib/pleroma/web/web_finger.ex

@@ -155,7 +155,16 @@ def get_template_from_xml(body) do
     end
   end
 
+  @cachex Pleroma.Config.get([:cachex, :provider], Cachex)
   def find_lrdd_template(domain) do
+    @cachex.fetch!(:host_meta_cache, domain, fn _ ->
+      {:commit, fetch_lrdd_template(domain)}
+    end)
+  rescue
+    e -> {:error, "Cachex error: #{inspect(e)}"}
+  end
+
+  defp fetch_lrdd_template(domain) do
     # WebFinger is restricted to HTTPS - https://tools.ietf.org/html/rfc7033#section-9.1
     meta_url = "https://#{domain}/.well-known/host-meta"
 
@@ -168,7 +177,7 @@ def find_lrdd_template(domain) do
     end
   end
 
-  defp get_address_from_domain(domain, encoded_account) when is_binary(domain) do
+  defp get_address_from_domain(domain, "acct:" <> _ = encoded_account) when is_binary(domain) do
     case find_lrdd_template(domain) do
       {:ok, template} ->
         String.replace(template, "{uri}", encoded_account)
@@ -178,6 +187,11 @@ defp get_address_from_domain(domain, encoded_account) when is_binary(domain) do
     end
   end
 
+  defp get_address_from_domain(domain, account) when is_binary(domain) do
+    encoded_account = URI.encode("acct:#{account}")
+    get_address_from_domain(domain, encoded_account)
+  end
+
   defp get_address_from_domain(_, _), do: {:error, :webfinger_no_domain}
 
   @spec finger(String.t()) :: {:ok, map()} | {:error, any()}
@@ -192,9 +206,7 @@ def finger(account) do
           URI.parse(account).host
       end
 
-    encoded_account = URI.encode("acct:#{account}")
+    with address when is_binary(address) <- get_address_from_domain(domain, account),
-
-    with address when is_binary(address) <- get_address_from_domain(domain, encoded_account),
          {:ok, %{status: status, body: body, headers: headers}} when status in 200..299 <-
            HTTP.get(
              address,
@@ -216,10 +228,28 @@ def finger(account) do
         _ ->
           {:error, {:content_type, nil}}
       end
+      |> case do
+        {:ok, data} -> validate_webfinger(address, data)
+        error -> error
+      end
     else
       error ->
         Logger.debug("Couldn't finger #{account}: #{inspect(error)}")
         error
     end
   end
+
+  defp validate_webfinger(request_url, %{"subject" => "acct:" <> acct = subject} = data) do
+    with [_name, acct_host] <- String.split(acct, "@"),
+         {_, url} <- {:address, get_address_from_domain(acct_host, subject)},
+         %URI{host: request_host} <- URI.parse(request_url),
+         %URI{host: acct_host} <- URI.parse(url),
+         {_, true} <- {:hosts_match, acct_host == request_host} do
+      {:ok, data}
+    else
+      _ -> {:error, {:webfinger_invalid, request_url, data}}
+    end
+  end
+
+  defp validate_webfinger(url, data), do: {:error, {:webfinger_invalid, url, data}}
 end

test/fixtures/tesla_mock/gleasonator.com_host_meta

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
+  <Link rel="lrdd" template="https://gleasonator.com/.well-known/webfinger?resource={uri}" type="application/xrd+xml" />
+</XRD>

test/fixtures/tesla_mock/webfinger_spoof.json

@@ -0,0 +1,28 @@
+{
+  "aliases": [
+    "https://gleasonator.com/users/alex",
+    "https://mitra.social/users/alex"
+  ],
+  "links": [
+    {
+      "href": "https://gleasonator.com/users/alex",
+      "rel": "http://webfinger.net/rel/profile-page",
+      "type": "text/html"
+    },
+    {
+      "href": "https://gleasonator.com/users/alex",
+      "rel": "self",
+      "type": "application/activity+json"
+    },
+    {
+      "href": "https://gleasonator.com/users/alex",
+      "rel": "self",
+      "type": "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\""
+    },
+    {
+      "rel": "http://ostatus.org/schema/1.0/subscribe",
+      "template": "https://gleasonator.com/ostatus_subscribe?acct={uri}"
+    }
+  ],
+  "subject": "acct:trump@whitehouse.gov"
+}

test/fixtures/webfinger/graf-imposter-webfinger.json

@@ -0,0 +1,41 @@
+{
+    "subject": "acct:graf@poa.st",
+    "aliases": [
+        "https://fba.ryona.agenc/webfingertest"
+    ],
+    "links": [
+        {
+            "rel": "http://webfinger.net/rel/profile-page",
+            "type": "text/html",
+            "href": "https://fba.ryona.agenc/webfingertest"
+        },
+        {
+            "rel": "self",
+            "type": "application/activity+json",
+            "href": "https://fba.ryona.agenc/webfingertest"
+        },
+        {
+            "rel": "http://ostatus.org/schema/1.0/subscribe",
+            "template": "https://fba.ryona.agenc/contact/follow?url={uri}"
+        },
+        {
+            "rel": "http://schemas.google.com/g/2010#updates-from",
+            "type": "application/atom+xml",
+            "href": ""
+        },
+        {
+            "rel": "salmon",
+            "href": "https://fba.ryona.agenc/salmon/friendica"
+        },
+        {
+            "rel": "http://microformats.org/profile/hcard",
+            "type": "text/html",
+            "href": "https://fba.ryona.agenc/hcard/friendica"
+        },
+        {
+            "rel": "http://joindiaspora.com/seed_location",
+            "type": "text/html",
+            "href": "https://fba.ryona.agenc"
+        }
+    ]
+}

test/pleroma/user_test.exs

@@ -877,109 +877,19 @@ test "gets an existing user by nickname starting with http" do
     setup do: clear_config([Pleroma.Web.WebFinger, :update_nickname_on_user_fetch], true)
 
     test "for mastodon" do
-      Tesla.Mock.mock(fn
+      ap_id = "a@mastodon.example"
-        %{url: "https://example.com/.well-known/host-meta"} ->
-          %Tesla.Env{
-            status: 302,
-            headers: [{"location", "https://sub.example.com/.well-known/host-meta"}]
-          }
-
-        %{url: "https://sub.example.com/.well-known/host-meta"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/masto-host-meta.xml"
-              |> File.read!()
-              |> String.replace("{{domain}}", "sub.example.com")
-          }
-
-        %{url: "https://sub.example.com/.well-known/webfinger?resource=acct:a@example.com"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/masto-webfinger.json"
-              |> File.read!()
-              |> String.replace("{{nickname}}", "a")
-              |> String.replace("{{domain}}", "example.com")
-              |> String.replace("{{subdomain}}", "sub.example.com"),
-            headers: [{"content-type", "application/jrd+json"}]
-          }
-
-        %{url: "https://sub.example.com/users/a"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/masto-user.json"
-              |> File.read!()
-              |> String.replace("{{nickname}}", "a")
-              |> String.replace("{{domain}}", "sub.example.com"),
-            headers: [{"content-type", "application/activity+json"}]
-          }
-
-        %{url: "https://sub.example.com/users/a/collections/featured"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              File.read!("test/fixtures/users_mock/masto_featured.json")
-              |> String.replace("{{domain}}", "sub.example.com")
-              |> String.replace("{{nickname}}", "a"),
-            headers: [{"content-type", "application/activity+json"}]
-          }
-      end)
-
-      ap_id = "a@example.com"
       {:ok, fetched_user} = User.get_or_fetch(ap_id)
 
-      assert fetched_user.ap_id == "https://sub.example.com/users/a"
+      assert fetched_user.ap_id == "https://sub.mastodon.example/users/a"
-      assert fetched_user.nickname == "a@example.com"
+      assert fetched_user.nickname == "a@mastodon.example"
     end
 
     test "for pleroma" do
-      Tesla.Mock.mock(fn
+      ap_id = "a@pleroma.example"
-        %{url: "https://example.com/.well-known/host-meta"} ->
-          %Tesla.Env{
-            status: 302,
-            headers: [{"location", "https://sub.example.com/.well-known/host-meta"}]
-          }
-
-        %{url: "https://sub.example.com/.well-known/host-meta"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/pleroma-host-meta.xml"
-              |> File.read!()
-              |> String.replace("{{domain}}", "sub.example.com")
-          }
-
-        %{url: "https://sub.example.com/.well-known/webfinger?resource=acct:a@example.com"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/pleroma-webfinger.json"
-              |> File.read!()
-              |> String.replace("{{nickname}}", "a")
-              |> String.replace("{{domain}}", "example.com")
-              |> String.replace("{{subdomain}}", "sub.example.com"),
-            headers: [{"content-type", "application/jrd+json"}]
-          }
-
-        %{url: "https://sub.example.com/users/a"} ->
-          %Tesla.Env{
-            status: 200,
-            body:
-              "test/fixtures/webfinger/pleroma-user.json"
-              |> File.read!()
-              |> String.replace("{{nickname}}", "a")
-              |> String.replace("{{domain}}", "sub.example.com"),
-            headers: [{"content-type", "application/activity+json"}]
-          }
-      end)
-
-      ap_id = "a@example.com"
       {:ok, fetched_user} = User.get_or_fetch(ap_id)
 
-      assert fetched_user.ap_id == "https://sub.example.com/users/a"
+      assert fetched_user.ap_id == "https://sub.pleroma.example/users/a"
-      assert fetched_user.nickname == "a@example.com"
+      assert fetched_user.nickname == "a@pleroma.example"
     end
   end
 

test/pleroma/web/web_finger_test.exs

@@ -76,15 +76,6 @@ test "returns the ActivityPub actor URI for an ActivityPub user" do
       {:ok, _data} = WebFinger.finger(user)
     end
 
-    test "returns the ActivityPub actor URI and subscribe address for an ActivityPub user with the ld+json mimetype" do
-      user = "kaniini@gerzilla.de"
-
-      {:ok, data} = WebFinger.finger(user)
-
-      assert data["ap_id"] == "https://gerzilla.de/channel/kaniini"
-      assert data["subscribe_address"] == "https://gerzilla.de/follow?f=&url={uri}"
-    end
-
     test "it work for AP-only user" do
       user = "kpherox@mstdn.jp"
 
@@ -99,12 +90,6 @@ test "it work for AP-only user" do
       assert data["subscribe_address"] == "https://mstdn.jp/authorize_interaction?acct={uri}"
     end
 
-    test "it works for friendica" do
-      user = "lain@squeet.me"
-
-      {:ok, _data} = WebFinger.finger(user)
-    end
-
     test "it gets the xrd endpoint" do
       {:ok, template} = WebFinger.find_lrdd_template("social.heldscal.la")
 
@@ -203,5 +188,44 @@ test "refuses to process XML remote entities" do
 
       assert :error = WebFinger.finger("pekorino@pawoo.net")
     end
+
+    test "prevents spoofing" do
+      Tesla.Mock.mock(fn
+        %{
+          url: "https://gleasonator.com/.well-known/webfinger?resource=acct:alex@gleasonator.com"
+        } ->
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: File.read!("test/fixtures/tesla_mock/webfinger_spoof.json"),
+             headers: [{"content-type", "application/jrd+json"}]
+           }}
+
+        %{url: "https://gleasonator.com/.well-known/host-meta"} ->
+          {:ok,
+           %Tesla.Env{
+             status: 200,
+             body: File.read!("test/fixtures/tesla_mock/gleasonator.com_host_meta")
+           }}
+      end)
+
+      {:error, _data} = WebFinger.finger("alex@gleasonator.com")
+    end
+  end
+
+  @tag capture_log: true
+  test "prevents forgeries" do
+    Tesla.Mock.mock(fn
+      %{url: "https://fba.ryona.agency/.well-known/webfinger?resource=acct:graf@fba.ryona.agency"} ->
+        fake_webfinger =
+          File.read!("test/fixtures/webfinger/graf-imposter-webfinger.json") |> Jason.decode!()
+
+        Tesla.Mock.json(fake_webfinger)
+
+      %{url: "https://fba.ryona.agency/.well-known/host-meta"} ->
+        {:ok, %Tesla.Env{status: 404}}
+    end)
+
+    assert {:error, _} = WebFinger.finger("graf@fba.ryona.agency")
   end
 end

test/support/http_request_mock.ex

@@ -1521,6 +1521,120 @@ def get("https://friends.grishka.me/users/1", _, _, _) do
      }}
   end
 
+  def get("https://mastodon.example/.well-known/host-meta", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 302,
+       headers: [{"location", "https://sub.mastodon.example/.well-known/host-meta"}]
+     }}
+  end
+
+  def get("https://sub.mastodon.example/.well-known/host-meta", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/masto-host-meta.xml"
+         |> File.read!()
+         |> String.replace("{{domain}}", "sub.mastodon.example")
+     }}
+  end
+
+  def get(
+        "https://sub.mastodon.example/.well-known/webfinger?resource=acct:a@mastodon.example",
+        _,
+        _,
+        _
+      ) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/masto-webfinger.json"
+         |> File.read!()
+         |> String.replace("{{nickname}}", "a")
+         |> String.replace("{{domain}}", "mastodon.example")
+         |> String.replace("{{subdomain}}", "sub.mastodon.example"),
+       headers: [{"content-type", "application/jrd+json"}]
+     }}
+  end
+
+  def get("https://sub.mastodon.example/users/a", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/masto-user.json"
+         |> File.read!()
+         |> String.replace("{{nickname}}", "a")
+         |> String.replace("{{domain}}", "sub.mastodon.example"),
+       headers: [{"content-type", "application/activity+json"}]
+     }}
+  end
+
+  def get("https://sub.mastodon.example/users/a/collections/featured", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         File.read!("test/fixtures/users_mock/masto_featured.json")
+         |> String.replace("{{domain}}", "sub.mastodon.example")
+         |> String.replace("{{nickname}}", "a"),
+       headers: [{"content-type", "application/activity+json"}]
+     }}
+  end
+
+  def get("https://pleroma.example/.well-known/host-meta", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 302,
+       headers: [{"location", "https://sub.pleroma.example/.well-known/host-meta"}]
+     }}
+  end
+
+  def get("https://sub.pleroma.example/.well-known/host-meta", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/pleroma-host-meta.xml"
+         |> File.read!()
+         |> String.replace("{{domain}}", "sub.pleroma.example")
+     }}
+  end
+
+  def get(
+        "https://sub.pleroma.example/.well-known/webfinger?resource=acct:a@pleroma.example",
+        _,
+        _,
+        _
+      ) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/pleroma-webfinger.json"
+         |> File.read!()
+         |> String.replace("{{nickname}}", "a")
+         |> String.replace("{{domain}}", "pleroma.example")
+         |> String.replace("{{subdomain}}", "sub.pleroma.example"),
+       headers: [{"content-type", "application/jrd+json"}]
+     }}
+  end
+
+  def get("https://sub.pleroma.example/users/a", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body:
+         "test/fixtures/webfinger/pleroma-user.json"
+         |> File.read!()
+         |> String.replace("{{nickname}}", "a")
+         |> String.replace("{{domain}}", "sub.pleroma.example"),
+       headers: [{"content-type", "application/activity+json"}]
+     }}
+  end
+
   def get(url, query, body, headers) do
     {:error,
      "Mock response not implemented for GET #{inspect(url)}, #{query}, #{inspect(body)}, #{inspect(headers)}"}