Revert to Cowboy as the webserver

While using Bandit, it was discovered that a herd of _disconnects_
could cause catastrophic failures leading to node crashes (in our
testing, these were decently sized 4-core, 8GB instances with 5-6k
devices connected). When testing again with Cowboy, the problem
was resolved.

This change reverts to use cowboy to allow progression of other
fixes and features while Bandit/Thousand Island is investigated to
find the root cause

config/config.exs

@@ -24,15 +24,13 @@ config :nerves_hub,
 # NervesHub Device
 #
 config :nerves_hub, NervesHubWeb.DeviceEndpoint,
-  adapter: Bandit.PhoenixAdapter,
   render_errors: [view: NervesHubWeb.ErrorView, accepts: ~w(html json)],
   pubsub_server: NervesHub.PubSub
 
 ##
 # NervesHub Web
 #
 config :nerves_hub, NervesHubWeb.Endpoint,
-  adapter: Bandit.PhoenixAdapter,
   secret_key_base: "ZH9GG2S5CwIMWXBg92wUuoyKFrjgqaAybHLTLuUk1xZO0HeidcJbnMBSTHDcyhSn",
   live_view: [
     signing_salt: "Kct3W8U7uQ6KAczYjzNbiYS6A8Pbtk3f"

config/dev.exs

@@ -43,27 +43,22 @@ config :nerves_hub, NervesHubWeb.DeviceEndpoint,
     ip: {0, 0, 0, 0},
     port: 4001,
     otp_app: :nerves_hub,
-    thousand_island_options: [
-      transport_module: NervesHub.DeviceSSLTransport,
-      transport_options: [
-        # Enable client SSL
-        # Older versions of OTP 25 may break using using devices
-        # that support TLS 1.3 or 1.2 negotiation. To mitigate that
-        # potential error, we enforce TLS 1.2. If you're using OTP >= 25.1
-        # on all devices, then it is safe to allow TLS 1.3 by removing
-        # the versions constraint and setting `certificate_authorities: false`
-        # See https://github.com/erlang/otp/issues/6492#issuecomment-1323874205
-        #
-        # certificate_authorities: false,
-        versions: [:"tlsv1.2"],
-        verify: :verify_peer,
-        verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
-        fail_if_no_peer_cert: true,
-        keyfile: Path.join(ssl_dir, "device.nerves-hub.org-key.pem"),
-        certfile: Path.join(ssl_dir, "device.nerves-hub.org.pem"),
-        cacertfile: Path.join(ssl_dir, "ca.pem")
-      ]
-    ]
+    # Enable client SSL
+    # Older versions of OTP 25 may break using using devices
+    # that support TLS 1.3 or 1.2 negotiation. To mitigate that
+    # potential error, we enforce TLS 1.2. If you're using OTP >= 25.1
+    # on all devices, then it is safe to allow TLS 1.3 by removing
+    # the versions constraint and setting `certificate_authorities: false`
+    # See https://github.com/erlang/otp/issues/6492#issuecomment-1323874205
+    #
+    # certificate_authorities: false,
+    versions: [:"tlsv1.2"],
+    verify: :verify_peer,
+    verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
+    fail_if_no_peer_cert: true,
+    keyfile: Path.join(ssl_dir, "device.nerves-hub.org-key.pem"),
+    certfile: Path.join(ssl_dir, "device.nerves-hub.org.pem"),
+    cacertfile: Path.join(ssl_dir, "ca.pem")
   ]
 
 ##

config/runtime.exs

@@ -105,29 +105,24 @@ if config_env() == :prod do
       https: [
         port: https_port,
         otp_app: :nerves_hub,
-        thousand_island_options: [
-          transport_module: NervesHub.DeviceSSLTransport,
-          transport_options: [
-            # Enable client SSL
-            # Older versions of OTP 25 may break using using devices
-            # that support TLS 1.3 or 1.2 negotiation. To mitigate that
-            # potential error, we enforce TLS 1.2. If you're using OTP >= 25.1
-            # on all devices, then it is safe to allow TLS 1.3 by removing
-            # the versions constraint and setting `certificate_authorities: false`
-            # since we don't expect devices to send full chains to the server
-            # See https://github.com/erlang/otp/issues/6492#issuecomment-1323874205
-            #
-            # certificate_authorities: false,
-            versions: [:"tlsv1.2"],
-            verify: :verify_peer,
-            verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
-            fail_if_no_peer_cert: true,
-            keyfile: keyfile,
-            certfile: certfile,
-            cacertfile: CAStore.file_path(),
-            hibernate_after: 15_000
-          ]
-        ]
+        # Enable client SSL
+        # Older versions of OTP 25 may break using using devices
+        # that support TLS 1.3 or 1.2 negotiation. To mitigate that
+        # potential error, we enforce TLS 1.2. If you're using OTP >= 25.1
+        # on all devices, then it is safe to allow TLS 1.3 by removing
+        # the versions constraint and setting `certificate_authorities: false`
+        # since we don't expect devices to send full chains to the server
+        # See https://github.com/erlang/otp/issues/6492#issuecomment-1323874205
+        #
+        # certificate_authorities: false,
+        versions: [:"tlsv1.2"],
+        verify: :verify_peer,
+        verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
+        fail_if_no_peer_cert: true,
+        keyfile: keyfile,
+        certfile: certfile,
+        cacertfile: CAStore.file_path(),
+        hibernate_after: 15_000
       ]
   end
 end

config/test.exs

@@ -25,17 +25,13 @@ config :nerves_hub, NervesHubWeb.DeviceEndpoint,
   https: [
     port: 4101,
     otp_app: :nerves_hub,
-    thousand_island_options: [
-      transport_options: [
-        # Enable client SSL
-        verify: :verify_peer,
-        verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
-        fail_if_no_peer_cert: true,
-        keyfile: Path.join([__DIR__, "../test/fixtures/ssl/device.nerves-hub.org-key.pem"]),
-        certfile: Path.join([__DIR__, "../test/fixtures/ssl/device.nerves-hub.org.pem"]),
-        cacertfile: Path.join([__DIR__, "../test/fixtures/ssl/ca.pem"])
-      ]
-    ]
+    # Enable client SSL
+    verify: :verify_peer,
+    verify_fun: {&NervesHub.SSL.verify_fun/3, nil},
+    fail_if_no_peer_cert: true,
+    keyfile: Path.join([__DIR__, "../test/fixtures/ssl/device.nerves-hub.org-key.pem"]),
+    certfile: Path.join([__DIR__, "../test/fixtures/ssl/device.nerves-hub.org.pem"]),
+    cacertfile: Path.join([__DIR__, "../test/fixtures/ssl/ca.pem"])
   ]
 
 ##

lib/nerves_hub/ssl.ex

@@ -1,6 +1,7 @@
 defmodule NervesHub.SSL do
   alias NervesHub.Devices
   alias NervesHub.Certificate
+  alias NervesHub.RateLimit
 
   @type pkix_path_validation_reason ::
           :cert_expired
@@ -33,42 +34,51 @@ defmodule NervesHub.SSL do
   # or the signer cert was included by the client and is valid
   # for the peer (device) cert
   def verify_fun(otp_cert, :valid_peer, state) do
-    :telemetry.execute([:nerves_hub, :rate_limit, :accepted], %{count: 1})
-
-    do_verify(otp_cert, state)
+    if RateLimit.increment() do
+      :telemetry.execute([:nerves_hub, :rate_limit, :accepted], %{count: 1})
+      do_verify(otp_cert, state)
+    else
+      :telemetry.execute([:nerves_hub, :rate_limit, :rejected], %{count: 1})
+      {:fail, :rate_limit}
+    end
   end
 
   def verify_fun(_certificate, :valid, state) do
     {:valid, state}
   end
 
   def verify_fun(otp_cert, {:bad_cert, err}, state) when err in [:unknown_ca, :cert_expired] do
-    :telemetry.execute([:nerves_hub, :rate_limit, :accepted], %{count: 1})
-
-    aki = Certificate.get_aki(otp_cert)
-    ski = Certificate.get_ski(otp_cert)
-
-    cond do
-      aki == ski ->
-        # If the signer CA is also the root, then AKI == SKI. We can skip
-        # checking as it will be validated later on if the device needs
-        # registration
-        {:valid, state}
-
-      is_binary(ski) and match?({:ok, _db_ca}, Devices.get_ca_certificate_by_ski(ski)) ->
-        # Signer CA sent with the device certificate, but is an intermediary
-        # so the chain is incomplete labeling it as unknown_ca.
-        #
-        # Since we have this CA registered, validate so we can move on to the device
-        # cert next and expiration will be checked later if registration of a new
-        # device cert needs to happen.
-        {:valid, state}
-
-      true ->
-        # The signer CA was not included in the request, so this is most
-        # likely a device cert that needs verification. If it isn't, then
-        # this is some other unknown CA that will fail
-        do_verify(otp_cert, state)
+    if RateLimit.increment() do
+      :telemetry.execute([:nerves_hub, :rate_limit, :accepted], %{count: 1})
+
+      aki = Certificate.get_aki(otp_cert)
+      ski = Certificate.get_ski(otp_cert)
+
+      cond do
+        aki == ski ->
+          # If the signer CA is also the root, then AKI == SKI. We can skip
+          # checking as it will be validated later on if the device needs
+          # registration
+          {:valid, state}
+
+        is_binary(ski) and match?({:ok, _db_ca}, Devices.get_ca_certificate_by_ski(ski)) ->
+          # Signer CA sent with the device certificate, but is an intermediary
+          # so the chain is incomplete labeling it as unknown_ca.
+          #
+          # Since we have this CA registered, validate so we can move on to the device
+          # cert next and expiration will be checked later if registration of a new
+          # device cert needs to happen.
+          {:valid, state}
+
+        true ->
+          # The signer CA was not included in the request, so this is most
+          # likely a device cert that needs verification. If it isn't, then
+          # this is some other unknown CA that will fail
+          do_verify(otp_cert, state)
+      end
+    else
+      :telemetry.execute([:nerves_hub, :rate_limit, :rejected], %{count: 1})
+      {:fail, :rate_limit}
     end
   end
 

mix.exs

@@ -51,12 +51,12 @@ defmodule NervesHub.MixProject do
     [
       {:mix_test_watch, "~> 1.0", only: :test, runtime: false},
       {:recon, "~> 2.5"},
-      {:bandit, "~> 1.0"},
       {:base62, "~> 1.2"},
       {:bcrypt_elixir, "~> 3.0"},
       {:castore, "~> 1.0"},
       {:circular_buffer, "~> 0.4.1"},
       {:comeonin, "~> 5.3"},
+      {:cowboy, "~> 2.0"},
       {:crontab, "~> 1.1"},
       {:decorator, "~> 1.2"},
       {:ecto, "~> 3.8", override: true},
@@ -85,6 +85,7 @@ defmodule NervesHub.MixProject do
       {:phoenix_swoosh, "~> 1.0"},
       {:phoenix_view, "~> 2.0"},
       {:plug, "~> 1.7"},
+      {:plug_cowboy, "~> 2.1"},
       {:postgrex, "~> 0.14"},
       {:scrivener_ecto, "~> 2.7"},
       {:scrivener_html, git: "https://github.com/nerves-hub/scrivener_html", branch: "phx-1.5"},