From f516e317ea639bf0d2cdf3d1f1e2e00b5b7c90ef Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:10:21 +0000
Subject: [PATCH 01/12] plugs: add CSPPlug

---
 lib/pleroma/plugs/csp_plug.ex | 38 +++++++++++++++++++++++++++++++++++
 lib/pleroma/web/endpoint.ex   |  1 +
 2 files changed, 39 insertions(+)
 create mode 100644 lib/pleroma/plugs/csp_plug.ex

diff --git a/lib/pleroma/plugs/csp_plug.ex b/lib/pleroma/plugs/csp_plug.ex
new file mode 100644
index 000000000..15d466c36
--- /dev/null
+++ b/lib/pleroma/plugs/csp_plug.ex
@@ -0,0 +1,38 @@
+defmodule Pleroma.Plugs.CSPPlug do
+  import Plug.Conn
+
+  def init(opts), do: opts
+
+  def call(conn, options) do
+    conn = merge_resp_headers(conn, headers())
+  end
+
+  defp headers do
+    [
+      {"x-xss-protection", "1; mode=block"},
+      {"x-permitted-cross-domain-policies", "none"},
+      {"x-frame-options", "DENY"},
+      {"x-content-type-options", "nosniff"},
+      {"referrer-policy", "same-origin"},
+      {"x-download-options", "noopen"},
+      {"content-security-policy", csp_string() <> ";"}
+    ]
+  end
+
+  defp csp_string do
+    [
+      "default-src 'none'",
+      "base-uri 'self'",
+      "form-action *",
+      "frame-ancestors 'none'",
+      "img-src 'self' data: https:",
+      "media-src 'self' https:",
+      "style-src 'self' 'unsafe-inline'",
+      "font-src 'self'",
+      "script-src 'self'",
+      "connect-src 'self' " <> String.replace(Pleroma.Web.Endpoint.static_url(), "http", "ws"),
+      "upgrade-insecure-requests"
+    ]
+    |> Enum.join("; ")
+  end
+end
diff --git a/lib/pleroma/web/endpoint.ex b/lib/pleroma/web/endpoint.ex
index cb5de087b..370d2d792 100644
--- a/lib/pleroma/web/endpoint.ex
+++ b/lib/pleroma/web/endpoint.ex
@@ -12,6 +12,7 @@ defmodule Pleroma.Web.Endpoint do
   # You should set gzip to true if you are running phoenix.digest
   # when deploying your static files in production.
   plug(CORSPlug)
+  plug(Pleroma.Plugs.CSPPlug)
 
   plug(Plug.Static, at: "/media", from: Pleroma.Uploaders.Local.upload_path(), gzip: false)
 

From 057a9017b3852f10e76165b70b907d9af458c301 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:12:26 +0000
Subject: [PATCH 02/12] example configs: remove obsolete CSP configuration

---
 installation/caddyfile-pleroma.example | 17 -----------------
 installation/pleroma-apache.conf       |  6 ------
 installation/pleroma.nginx             |  8 --------
 installation/pleroma.vcl               |  5 -----
 4 files changed, 36 deletions(-)

diff --git a/installation/caddyfile-pleroma.example b/installation/caddyfile-pleroma.example
index 305f2aa79..c34b47045 100644
--- a/installation/caddyfile-pleroma.example
+++ b/installation/caddyfile-pleroma.example
@@ -22,27 +22,10 @@ example.tld  {
   }
 
   header / {
-    X-XSS-Protection "1; mode=block"
-    X-Frame-Options "DENY"
-    X-Content-Type-Options "nosniff"
-    Referrer-Policy "same-origin"
     Strict-Transport-Security "max-age=31536000; includeSubDomains;"
     Expect-CT "enforce, max-age=2592000"
-    Content-Security-Policy "default-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'; img-src 'self' data: https:; media-src 'self' https:; style-src 'self' 'unsafe-inline'; font-src 'self'; script-src 'self'; connect-src 'self' wss://{host}; upgrade-insecure-requests;"
   }
 
-  # If you do not want remote frontends to be able to access your Pleroma backend server, remove these lines.
-  # If you want to allow all origins access, remove the origin lines.
-  # To use this directive, you need the http.cors plugin for Caddy.
-  cors / {
-    origin https://halcyon.example.tld
-    origin https://pinafore.example.tld
-    methods POST,PUT,DELETE,GET,PATCH,OPTIONS
-    allowed_headers Authorization,Content-Type,Idempotency-Key
-    exposed_headers Link,X-RateLimit-Reset,X-RateLimit-Limit,X-RateLimit-Remaining,X-Request-Id
-  }
-  # Stop removing lines here.
-
   # If you do not want to use the mediaproxy function, remove these lines.
   # To use this directive, you need the http.cache plugin for Caddy.
   cache {
diff --git a/installation/pleroma-apache.conf b/installation/pleroma-apache.conf
index fb777983e..cbb165064 100644
--- a/installation/pleroma-apache.conf
+++ b/installation/pleroma-apache.conf
@@ -34,12 +34,6 @@ CustomLog ${APACHE_LOG_DIR}/access.log combined
     SSLCompression          off
     SSLSessionTickets       off
 
-    Header always set X-Xss-Protection "1; mode=block"
-    Header always set X-Frame-Options "DENY"
-    Header always set X-Content-Type-Options "nosniff"
-    Header always set Referrer-Policy same-origin
-    Header always set Content-Security-Policy "default-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'; img-src 'self' data: https:; media-src 'self' https:; style-src 'self' 'unsafe-inline'; font-src 'self'; script-src 'self'; connect-src 'self' wss://${servername}; upgrade-insecure-requests;"
-
     # Uncomment this only after you get HTTPS working.
     # Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
 
diff --git a/installation/pleroma.nginx b/installation/pleroma.nginx
index 9b7419497..62c99383f 100644
--- a/installation/pleroma.nginx
+++ b/installation/pleroma.nginx
@@ -60,14 +60,6 @@ server {
     client_max_body_size 16m;
 
     location / {
-        add_header X-XSS-Protection "1; mode=block" always;
-        add_header X-Permitted-Cross-Domain-Policies "none" always;
-        add_header X-Frame-Options "DENY" always;
-        add_header X-Content-Type-Options "nosniff" always;
-        add_header Referrer-Policy "same-origin" always;
-        add_header X-Download-Options "noopen" always;
-        add_header Content-Security-Policy "default-src 'none'; base-uri 'self'; form-action *; frame-ancestors 'none'; img-src 'self' data: https:; media-src 'self' https:; style-src 'self' 'unsafe-inline'; font-src 'self'; script-src 'self'; connect-src 'self' wss://$server_name; upgrade-insecure-requests;" always;
-
         # Uncomment this only after you get HTTPS working.
         # add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
 
diff --git a/installation/pleroma.vcl b/installation/pleroma.vcl
index 74490be2a..5d80c6f44 100644
--- a/installation/pleroma.vcl
+++ b/installation/pleroma.vcl
@@ -121,11 +121,6 @@ sub vcl_pipe {
 }
 
 sub vcl_deliver {
-  set resp.http.X-Frame-Options = "DENY";
-  set resp.http.X-XSS-Protection = "1; mode=block";
-  set resp.http.X-Content-Type-Options = "nosniff";
-  set resp.http.Referrer-Policy = "same-origin";
-  set resp.http.Content-Security-Policy = "default-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'; img-src 'self' data: https:; media-src 'self' https:; style-src 'self' 'unsafe-inline'; font-src 'self'; script-src 'self'; connect-src 'self' wss://" + req.http.host + "; upgrade-insecure-requests;";
   # Uncomment this only after you get HTTPS working.
   # set resp.http.Strict-Transport-Security= "max-age=31536000; includeSubDomains";
 }

From 69f5dfcfb3f2b498e1f9957244f0896b6f9d5c2a Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:37:18 +0000
Subject: [PATCH 03/12] config: add default parameters for CSPPlug

---
 config/config.exs | 5 +++++
 config/config.md  | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/config/config.exs b/config/config.exs
index e82c490e3..ad8653025 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -176,6 +176,11 @@ config :pleroma, :suggestions,
   limit: 23,
   web: "https://vinayaka.distsn.org/?{{host}}+{{user}}"
 
+config :pleroma, :csp,
+  enabled: true,
+  sts: false,
+  sts_max_age: 31_536_000
+
 config :cors_plug,
   max_age: 86_400,
   methods: ["POST", "PUT", "DELETE", "GET", "PATCH", "OPTIONS"],
diff --git a/config/config.md b/config/config.md
index 51172fc4d..e08d206b6 100644
--- a/config/config.md
+++ b/config/config.md
@@ -80,3 +80,8 @@ This section is used to configure Pleroma-FE, unless ``:managed_config`` in ``:i
 * ``unfollow_blocked``: Whether blocks result in people getting unfollowed
 * ``outgoing_blocks``: Whether to federate blocks to other instances
 * ``deny_follow_blocked``: Whether to disallow following an account that has blocked the user in question
+
+## :csp
+* ``enabled``: Whether the managed content security policy is enabled
+* ``sts``: Whether to additionally send a `Strict-Transport-Security` header
+* ``sts_max_age``: The maximum age for the `Strict-Transport-Security` header if sent

From a2bf5426cb84940dbd58aec10a7b1b0a90f26a60 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:42:14 +0000
Subject: [PATCH 04/12] sample config: document how to make CSPPlug send STS
 headers (off by default to allow for SSL debugging)

---
 lib/mix/tasks/sample_config.eex | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/mix/tasks/sample_config.eex b/lib/mix/tasks/sample_config.eex
index 3881ead26..824bc97a1 100644
--- a/lib/mix/tasks/sample_config.eex
+++ b/lib/mix/tasks/sample_config.eex
@@ -25,6 +25,10 @@ config :pleroma, Pleroma.Repo,
   hostname: "localhost",
   pool_size: 10
 
+# Enable Strict-Transport-Security once SSL is working:
+# config :pleroma, :csp,
+#   sts: true
+
 # Configure S3 support if desired.
 # The public S3 endpoint is different depending on region and provider,
 # consult your S3 provider's documentation for details on what to use.

From 331cf6ada1e4df51b366c79126e094ee335dd684 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:50:28 +0000
Subject: [PATCH 05/12] csp plug: add sts support

---
 lib/pleroma/plugs/csp_plug.ex | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/pleroma/plugs/csp_plug.ex b/lib/pleroma/plugs/csp_plug.ex
index 15d466c36..56f2376ee 100644
--- a/lib/pleroma/plugs/csp_plug.ex
+++ b/lib/pleroma/plugs/csp_plug.ex
@@ -1,10 +1,17 @@
 defmodule Pleroma.Plugs.CSPPlug do
+  alias Pleroma.Config
   import Plug.Conn
 
   def init(opts), do: opts
 
   def call(conn, options) do
-    conn = merge_resp_headers(conn, headers())
+    if Config.get([:csp, :enabled]) do
+      conn =
+        merge_resp_headers(conn, headers())
+        |> maybe_send_sts_header(Config.get([:csp, :sts]))
+    else
+      conn
+    end
   end
 
   defp headers do
@@ -35,4 +42,14 @@ defmodule Pleroma.Plugs.CSPPlug do
     ]
     |> Enum.join("; ")
   end
+
+  defp maybe_send_sts_header(conn, true) do
+    max_age = Config.get([:csp, :sts_max_age])
+
+    merge_resp_headers(conn, [
+      {"strict-transport-security", "max-age=#{max_age}; includeSubDomains"}
+    ])
+  end
+
+  defp maybe_send_sts_header(conn, _), do: conn
 end

From df72978dce3805157537e8fa1a2fec35fcf9a7cd Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:53:42 +0000
Subject: [PATCH 06/12] csp plug: add support for certificate transparency

---
 config/config.exs             | 3 ++-
 config/config.md              | 1 +
 lib/pleroma/plugs/csp_plug.ex | 6 ++++--
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/config/config.exs b/config/config.exs
index ad8653025..1d918919d 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -179,7 +179,8 @@ config :pleroma, :suggestions,
 config :pleroma, :csp,
   enabled: true,
   sts: false,
-  sts_max_age: 31_536_000
+  sts_max_age: 31_536_000,
+  ct_max_age: 2_592_000
 
 config :cors_plug,
   max_age: 86_400,
diff --git a/config/config.md b/config/config.md
index e08d206b6..34f703560 100644
--- a/config/config.md
+++ b/config/config.md
@@ -85,3 +85,4 @@ This section is used to configure Pleroma-FE, unless ``:managed_config`` in ``:i
 * ``enabled``: Whether the managed content security policy is enabled
 * ``sts``: Whether to additionally send a `Strict-Transport-Security` header
 * ``sts_max_age``: The maximum age for the `Strict-Transport-Security` header if sent
+* ``ct_max_age``: The maximum age for the `Except-CT` header if sent
diff --git a/lib/pleroma/plugs/csp_plug.ex b/lib/pleroma/plugs/csp_plug.ex
index 56f2376ee..8fc21b909 100644
--- a/lib/pleroma/plugs/csp_plug.ex
+++ b/lib/pleroma/plugs/csp_plug.ex
@@ -44,10 +44,12 @@ defmodule Pleroma.Plugs.CSPPlug do
   end
 
   defp maybe_send_sts_header(conn, true) do
-    max_age = Config.get([:csp, :sts_max_age])
+    max_age_sts = Config.get([:csp, :sts_max_age])
+    max_age_ct = Config.get([:csp, :ct_max_age])
 
     merge_resp_headers(conn, [
-      {"strict-transport-security", "max-age=#{max_age}; includeSubDomains"}
+      {"strict-transport-security", "max-age=#{max_age_sts}; includeSubDomains"},
+      {"expect-ct", "enforce, max-age=#{max_age_ct}"}
     ])
   end
 

From e4bd5a6950d08eddbbc12ddd3f2e91c43544238c Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 06:56:46 +0000
Subject: [PATCH 07/12] example configs: kill STS/CT headers

---
 installation/caddyfile-pleroma.example | 5 -----
 installation/pleroma-apache.conf       | 3 ---
 installation/pleroma.nginx             | 3 ---
 installation/pleroma.vcl               | 5 -----
 4 files changed, 16 deletions(-)

diff --git a/installation/caddyfile-pleroma.example b/installation/caddyfile-pleroma.example
index c34b47045..03ff000b6 100644
--- a/installation/caddyfile-pleroma.example
+++ b/installation/caddyfile-pleroma.example
@@ -21,11 +21,6 @@ example.tld  {
     ciphers ECDHE-ECDSA-WITH-CHACHA20-POLY1305 ECDHE-RSA-WITH-CHACHA20-POLY1305 ECDHE-ECDSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-GCM-SHA384 ECDHE-ECDSA-AES128-GCM-SHA256 ECDHE-RSA-AES128-GCM-SHA256
   }
 
-  header / {
-    Strict-Transport-Security "max-age=31536000; includeSubDomains;"
-    Expect-CT "enforce, max-age=2592000"
-  }
-
   # If you do not want to use the mediaproxy function, remove these lines.
   # To use this directive, you need the http.cache plugin for Caddy.
   cache {
diff --git a/installation/pleroma-apache.conf b/installation/pleroma-apache.conf
index cbb165064..d5e75044f 100644
--- a/installation/pleroma-apache.conf
+++ b/installation/pleroma-apache.conf
@@ -34,9 +34,6 @@ CustomLog ${APACHE_LOG_DIR}/access.log combined
     SSLCompression          off
     SSLSessionTickets       off
 
-    # Uncomment this only after you get HTTPS working.
-    # Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
-
     RewriteEngine On
     RewriteCond %{HTTP:Connection} Upgrade [NC]
     RewriteCond %{HTTP:Upgrade} websocket [NC]
diff --git a/installation/pleroma.nginx b/installation/pleroma.nginx
index 62c99383f..f0e684f2c 100644
--- a/installation/pleroma.nginx
+++ b/installation/pleroma.nginx
@@ -60,9 +60,6 @@ server {
     client_max_body_size 16m;
 
     location / {
-        # Uncomment this only after you get HTTPS working.
-        # add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
-
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection "upgrade";
diff --git a/installation/pleroma.vcl b/installation/pleroma.vcl
index 5d80c6f44..63c1cb74d 100644
--- a/installation/pleroma.vcl
+++ b/installation/pleroma.vcl
@@ -119,8 +119,3 @@ sub vcl_pipe {
         set bereq.http.connection = req.http.connection;
     }
 }
-
-sub vcl_deliver {
-  # Uncomment this only after you get HTTPS working.
-  # set resp.http.Strict-Transport-Security= "max-age=31536000; includeSubDomains";
-}

From 54fdce9107af85321d3ce73ec59a48567dc1bdba Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 07:26:31 +0000
Subject: [PATCH 08/12] tests: add tests for CSPPlug

---
 test/plugs/csp_plug_test.exs | 61 ++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 test/plugs/csp_plug_test.exs

diff --git a/test/plugs/csp_plug_test.exs b/test/plugs/csp_plug_test.exs
new file mode 100644
index 000000000..e27b24db9
--- /dev/null
+++ b/test/plugs/csp_plug_test.exs
@@ -0,0 +1,61 @@
+defmodule Pleroma.Web.Plugs.CSPPlugTest do
+  use Pleroma.Web.ConnCase
+  alias Pleroma.Config
+  alias Plug.Conn
+
+  test "it sends CSP headers when enabled", %{conn: conn} do
+    Config.put([:csp, :enabled], true)
+
+    conn =
+      conn
+      |> get("/api/v1/instance")
+
+    refute Conn.get_resp_header(conn, "x-xss-protection") == []
+    refute Conn.get_resp_header(conn, "x-permitted-cross-domain-policies") == []
+    refute Conn.get_resp_header(conn, "x-frame-options") == []
+    refute Conn.get_resp_header(conn, "x-content-type-options") == []
+    refute Conn.get_resp_header(conn, "x-download-options") == []
+    refute Conn.get_resp_header(conn, "referrer-policy") == []
+    refute Conn.get_resp_header(conn, "content-security-policy") == []
+  end
+
+  test "it does not send CSP headers when disabled", %{conn: conn} do
+    Config.put([:csp, :enabled], false)
+
+    conn =
+      conn
+      |> get("/api/v1/instance")
+
+    assert Conn.get_resp_header(conn, "x-xss-protection") == []
+    assert Conn.get_resp_header(conn, "x-permitted-cross-domain-policies") == []
+    assert Conn.get_resp_header(conn, "x-frame-options") == []
+    assert Conn.get_resp_header(conn, "x-content-type-options") == []
+    assert Conn.get_resp_header(conn, "x-download-options") == []
+    assert Conn.get_resp_header(conn, "referrer-policy") == []
+    assert Conn.get_resp_header(conn, "content-security-policy") == []
+  end
+
+  test "it sends STS headers when enabled", %{conn: conn} do
+    Config.put([:csp, :enabled], true)
+    Config.put([:csp, :sts], true)
+
+    conn =
+      conn
+      |> get("/api/v1/instance")
+
+    refute Conn.get_resp_header(conn, "strict-transport-security") == []
+    refute Conn.get_resp_header(conn, "expect-ct") == []
+  end
+
+  test "it does not send STS headers when disabled", %{conn: conn} do
+    Config.put([:csp, :enabled], true)
+    Config.put([:csp, :sts], false)
+
+    conn =
+      conn
+      |> get("/api/v1/instance")
+
+    assert Conn.get_resp_header(conn, "strict-transport-security") == []
+    assert Conn.get_resp_header(conn, "expect-ct") == []
+  end
+end

From 5dda13ee5f9302cfef215c8ffaa527e9a572a37b Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sun, 11 Nov 2018 07:27:36 +0000
Subject: [PATCH 09/12] config docs: typo fix

---
 config/config.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/config/config.md b/config/config.md
index 34f703560..446b0ce67 100644
--- a/config/config.md
+++ b/config/config.md
@@ -85,4 +85,4 @@ This section is used to configure Pleroma-FE, unless ``:managed_config`` in ``:i
 * ``enabled``: Whether the managed content security policy is enabled
 * ``sts``: Whether to additionally send a `Strict-Transport-Security` header
 * ``sts_max_age``: The maximum age for the `Strict-Transport-Security` header if sent
-* ``ct_max_age``: The maximum age for the `Except-CT` header if sent
+* ``ct_max_age``: The maximum age for the `Expect-CT` header if sent

From fe67665e19cc98faff4a8ee53a3f4ca4190ca2ef Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 12 Nov 2018 15:08:02 +0000
Subject: [PATCH 10/12] rename CSPPlug to HTTPSecurityPlug.

---
 config/config.exs                                  |  2 +-
 config/config.md                                   |  2 +-
 .../plugs/{csp_plug.ex => http_security_plug.ex}   | 10 +++++-----
 lib/pleroma/web/endpoint.ex                        |  2 +-
 ...p_plug_test.exs => http_security_plug_test.exs} | 14 +++++++-------
 5 files changed, 15 insertions(+), 15 deletions(-)
 rename lib/pleroma/plugs/{csp_plug.ex => http_security_plug.ex} (82%)
 rename test/plugs/{csp_plug_test.exs => http_security_plug_test.exs} (84%)

diff --git a/config/config.exs b/config/config.exs
index 1d918919d..be9c03ceb 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -176,7 +176,7 @@ config :pleroma, :suggestions,
   limit: 23,
   web: "https://vinayaka.distsn.org/?{{host}}+{{user}}"
 
-config :pleroma, :csp,
+config :pleroma, :http_security,
   enabled: true,
   sts: false,
   sts_max_age: 31_536_000,
diff --git a/config/config.md b/config/config.md
index 446b0ce67..48af1c236 100644
--- a/config/config.md
+++ b/config/config.md
@@ -81,7 +81,7 @@ This section is used to configure Pleroma-FE, unless ``:managed_config`` in ``:i
 * ``outgoing_blocks``: Whether to federate blocks to other instances
 * ``deny_follow_blocked``: Whether to disallow following an account that has blocked the user in question
 
-## :csp
+## :http_security
 * ``enabled``: Whether the managed content security policy is enabled
 * ``sts``: Whether to additionally send a `Strict-Transport-Security` header
 * ``sts_max_age``: The maximum age for the `Strict-Transport-Security` header if sent
diff --git a/lib/pleroma/plugs/csp_plug.ex b/lib/pleroma/plugs/http_security_plug.ex
similarity index 82%
rename from lib/pleroma/plugs/csp_plug.ex
rename to lib/pleroma/plugs/http_security_plug.ex
index 8fc21b909..8d652a2f3 100644
--- a/lib/pleroma/plugs/csp_plug.ex
+++ b/lib/pleroma/plugs/http_security_plug.ex
@@ -1,14 +1,14 @@
-defmodule Pleroma.Plugs.CSPPlug do
+defmodule Pleroma.Plugs.HTTPSecurityPlug do
   alias Pleroma.Config
   import Plug.Conn
 
   def init(opts), do: opts
 
   def call(conn, options) do
-    if Config.get([:csp, :enabled]) do
+    if Config.get([:http_security, :enabled]) do
       conn =
         merge_resp_headers(conn, headers())
-        |> maybe_send_sts_header(Config.get([:csp, :sts]))
+        |> maybe_send_sts_header(Config.get([:http_security, :sts]))
     else
       conn
     end
@@ -44,8 +44,8 @@ defmodule Pleroma.Plugs.CSPPlug do
   end
 
   defp maybe_send_sts_header(conn, true) do
-    max_age_sts = Config.get([:csp, :sts_max_age])
-    max_age_ct = Config.get([:csp, :ct_max_age])
+    max_age_sts = Config.get([:http_security, :sts_max_age])
+    max_age_ct = Config.get([:http_security, :ct_max_age])
 
     merge_resp_headers(conn, [
       {"strict-transport-security", "max-age=#{max_age_sts}; includeSubDomains"},
diff --git a/lib/pleroma/web/endpoint.ex b/lib/pleroma/web/endpoint.ex
index 370d2d792..7783b8e5c 100644
--- a/lib/pleroma/web/endpoint.ex
+++ b/lib/pleroma/web/endpoint.ex
@@ -12,7 +12,7 @@ defmodule Pleroma.Web.Endpoint do
   # You should set gzip to true if you are running phoenix.digest
   # when deploying your static files in production.
   plug(CORSPlug)
-  plug(Pleroma.Plugs.CSPPlug)
+  plug(Pleroma.Plugs.HTTPSecurityPlug)
 
   plug(Plug.Static, at: "/media", from: Pleroma.Uploaders.Local.upload_path(), gzip: false)
 
diff --git a/test/plugs/csp_plug_test.exs b/test/plugs/http_security_plug_test.exs
similarity index 84%
rename from test/plugs/csp_plug_test.exs
rename to test/plugs/http_security_plug_test.exs
index e27b24db9..5268a1972 100644
--- a/test/plugs/csp_plug_test.exs
+++ b/test/plugs/http_security_plug_test.exs
@@ -1,10 +1,10 @@
-defmodule Pleroma.Web.Plugs.CSPPlugTest do
+defmodule Pleroma.Web.Plugs.HTTPSecurityPlugTest do
   use Pleroma.Web.ConnCase
   alias Pleroma.Config
   alias Plug.Conn
 
   test "it sends CSP headers when enabled", %{conn: conn} do
-    Config.put([:csp, :enabled], true)
+    Config.put([:http_security, :enabled], true)
 
     conn =
       conn
@@ -20,7 +20,7 @@ defmodule Pleroma.Web.Plugs.CSPPlugTest do
   end
 
   test "it does not send CSP headers when disabled", %{conn: conn} do
-    Config.put([:csp, :enabled], false)
+    Config.put([:http_security, :enabled], false)
 
     conn =
       conn
@@ -36,8 +36,8 @@ defmodule Pleroma.Web.Plugs.CSPPlugTest do
   end
 
   test "it sends STS headers when enabled", %{conn: conn} do
-    Config.put([:csp, :enabled], true)
-    Config.put([:csp, :sts], true)
+    Config.put([:http_security, :enabled], true)
+    Config.put([:http_security, :sts], true)
 
     conn =
       conn
@@ -48,8 +48,8 @@ defmodule Pleroma.Web.Plugs.CSPPlugTest do
   end
 
   test "it does not send STS headers when disabled", %{conn: conn} do
-    Config.put([:csp, :enabled], true)
-    Config.put([:csp, :sts], false)
+    Config.put([:http_security, :enabled], true)
+    Config.put([:http_security, :sts], false)
 
     conn =
       conn

From ee5932a504d69e591aad7bdd52bd97d1f92d4e32 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 12 Nov 2018 15:14:46 +0000
Subject: [PATCH 11/12] http security: allow referrer-policy to be configured

---
 config/config.exs                       |  3 ++-
 config/config.md                        |  1 +
 lib/pleroma/plugs/http_security_plug.ex |  4 +++-
 test/plugs/http_security_plug_test.exs  | 16 ++++++++++++++++
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/config/config.exs b/config/config.exs
index be9c03ceb..9cc558564 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -180,7 +180,8 @@ config :pleroma, :http_security,
   enabled: true,
   sts: false,
   sts_max_age: 31_536_000,
-  ct_max_age: 2_592_000
+  ct_max_age: 2_592_000,
+  referrer_policy: "same-origin"
 
 config :cors_plug,
   max_age: 86_400,
diff --git a/config/config.md b/config/config.md
index 48af1c236..5b4110646 100644
--- a/config/config.md
+++ b/config/config.md
@@ -86,3 +86,4 @@ This section is used to configure Pleroma-FE, unless ``:managed_config`` in ``:i
 * ``sts``: Whether to additionally send a `Strict-Transport-Security` header
 * ``sts_max_age``: The maximum age for the `Strict-Transport-Security` header if sent
 * ``ct_max_age``: The maximum age for the `Expect-CT` header if sent
+* ``referrer_policy``: The referrer policy to use, either `"same-origin"` or `"no-referrer"`.
diff --git a/lib/pleroma/plugs/http_security_plug.ex b/lib/pleroma/plugs/http_security_plug.ex
index 8d652a2f3..960c7f6bf 100644
--- a/lib/pleroma/plugs/http_security_plug.ex
+++ b/lib/pleroma/plugs/http_security_plug.ex
@@ -15,12 +15,14 @@ defmodule Pleroma.Plugs.HTTPSecurityPlug do
   end
 
   defp headers do
+    referrer_policy = Config.get([:http_security, :referrer_policy])
+
     [
       {"x-xss-protection", "1; mode=block"},
       {"x-permitted-cross-domain-policies", "none"},
       {"x-frame-options", "DENY"},
       {"x-content-type-options", "nosniff"},
-      {"referrer-policy", "same-origin"},
+      {"referrer-policy", referrer_policy},
       {"x-download-options", "noopen"},
       {"content-security-policy", csp_string() <> ";"}
     ]
diff --git a/test/plugs/http_security_plug_test.exs b/test/plugs/http_security_plug_test.exs
index 5268a1972..55040a108 100644
--- a/test/plugs/http_security_plug_test.exs
+++ b/test/plugs/http_security_plug_test.exs
@@ -58,4 +58,20 @@ defmodule Pleroma.Web.Plugs.HTTPSecurityPlugTest do
     assert Conn.get_resp_header(conn, "strict-transport-security") == []
     assert Conn.get_resp_header(conn, "expect-ct") == []
   end
+
+  test "referrer-policy header reflects configured value", %{conn: conn} do
+    conn =
+      conn
+      |> get("/api/v1/instance")
+
+    assert Conn.get_resp_header(conn, "referrer-policy") == ["same-origin"]
+
+    Config.put([:http_security, :referrer_policy], "no-referrer")
+
+    conn =
+      build_conn()
+      |> get("/api/v1/instance")
+
+    assert Conn.get_resp_header(conn, "referrer-policy") == ["no-referrer"]
+  end
 end

From 2829fa41830ad8565fc186c3dc110f4d275f8827 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 12 Nov 2018 15:17:04 +0000
Subject: [PATCH 12/12] sample config: chase http_security change

---
 lib/mix/tasks/sample_config.eex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mix/tasks/sample_config.eex b/lib/mix/tasks/sample_config.eex
index 824bc97a1..462c34636 100644
--- a/lib/mix/tasks/sample_config.eex
+++ b/lib/mix/tasks/sample_config.eex
@@ -26,7 +26,7 @@ config :pleroma, Pleroma.Repo,
   pool_size: 10
 
 # Enable Strict-Transport-Security once SSL is working:
-# config :pleroma, :csp,
+# config :pleroma, :http_security,
 #   sts: true
 
 # Configure S3 support if desired.