chore(deps): upgrade to Rails 7.2.3.2, Ruby 3.4.10 and latest gems

Upgrades Rails from 7.1.6 to 7.2.3.2, Ruby from 3.4.6 to 3.4.10, and
brings the rest of the bundle up to date.

Two things were broken by Rails 7.2 and are fixed here:

* MigrationWaiter called `ActiveRecord::Base.connection.migration_context`,
  which moved to the connection pool in 7.2. This raised NoMethodError on
  boot for any deployment with `migration_waiter.enabled` set, and had no
  test covering it.
* `config.action_dispatch.show_exceptions = false` was deprecated in 7.1
  and removed in 7.2. Now `:none`.

`json` is pinned to < 3. Active Support 7.2 passes `quirks_mode:` to both
`JSON.generate` and `JSON.parse`, and json 3.0 removed that option, so an
unpinned json resolves to 3.x and makes every `to_json` raise - webhook
payloads included. Nothing else in the bundle constrains it. The pin can go
when we reach Rails 8.1, which no longer passes the option.

`dynamic_form` is dropped. It is unmaintained and from 1.3.1 requires Ruby
< 3.4, so it could never be updated again. Ten views used it, so
`error_messages_for` now lives in ErrorMessagesHelper and `f.error_messages`
in a form builder extension. The rendered markup is unchanged apart from a
heading and description the stylesheet had always hidden; the rules that
hid them are removed too.

`execjs` is unpinned. The `< 2.8` constraint dated from the Rails 6.0
upgrade and asset output is byte-identical without it.

Notable gem majors: puma 8, haml 7, secure_headers 7, sentry 7, jwt 3,
prometheus-client 5, highline 3, omniauth-rails_csrf_protection 2,
rspec-rails 8, shoulda-matchers 8, rubocop 1.91. secure_headers 7 changes
X-XSS-Protection from "1; mode=block" to "0", which is the correct modern
default and matches Rails' own.

`config.load_defaults` deliberately stays at 7.0. The pending 7.1 and 7.2
options are listed, commented out, in new_framework_defaults_7_1.rb and
_7_2.rb so they can be adopted in stages - several change the signed cookie
and cache formats and need a staged deploy. The vestigial
new_framework_defaults_7_0.rb is removed, as `load_defaults 7.0` already
applies all of it.

Adds tests for the areas this touched, which were mostly uncovered:
MigrationWaiter, the serialized columns that gate a defaults bump, JSON
encoding, HAML template compilation for all 103 templates, page rendering,
form error rendering and security headers. The assets Gemfile group now
includes :test so the view layer can be exercised at all.

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "3.3.6"
+  ".": "3.3.7"
 }

.rubocop.yml

@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 3.4
   NewCops: enable
   Exclude:
     - "bin/*"
@@ -135,7 +135,7 @@ Style/FrozenStringLiteralComment:
   Enabled: true
   SafeAutoCorrect: true
 
-Naming/PredicateName:
+Naming/PredicatePrefix:
   Enabled: false
 
 Layout/LineLength:

.ruby-version

@@ -1 +1 @@
-3.4.6
+3.4.10

CHANGELOG.md

@@ -2,6 +2,21 @@
 
 This file contains all the latest changes and updates to Postal.
 
+## [3.3.7](https://github.com/postalserver/postal/compare/3.3.6...3.3.7) (2026-06-03)
+
+
+### Bug Fixes
+
+* **http:** prevent SSRF in outbound webhook and HTTP endpoint requests ([11c9814](https://github.com/postalserver/postal/commit/11c9814474f956619da35e8385ef7fab9f304de0))
+* **message-db:** prevent SQL injection via condition keys (GHSA-x2hq-rfpg-3xr5) ([4314a6e](https://github.com/postalserver/postal/commit/4314a6ec1e2812daa67dd20effd1db1769c1f8e8))
+* **specs:** stub IPv6 support in address guard IPv6 literal spec ([029bfe0](https://github.com/postalserver/postal/commit/029bfe098d9b8c0b5cafc49eac33e767f5748cd3))
+
+
+### Miscellaneous Chores
+
+* **deps:** upgrade rack & rails ([0445e5c](https://github.com/postalserver/postal/commit/0445e5c509870dfe9c16366c53dee3fc02ad3904))
+* update security vulnerability reporting instructions ([8be1e27](https://github.com/postalserver/postal/commit/8be1e27fec489ab659ef5e909f705932028b1694))
+
 ## [3.3.6](https://github.com/postalserver/postal/compare/3.3.5...3.3.6) (2026-04-28)
 
 

CONTRIBUTING.md

@@ -6,7 +6,7 @@ This doc explains how to go about running Postal in development to allow you to
 
 You will need a MySQL database server to get started. Postal needs to be able to make databases within that server whenever new mail servers are created so the permissions that you use should be suitable for that.
 
-You'll also need Ruby. Postal currently uses Ruby 3.2.2. Install that using whichever version manager takes your fancy - rbenv, asdf, rvm etc.
+You'll also need Ruby. Postal currently uses the Ruby version in `.ruby-version`. Install that using whichever version manager takes your fancy - rbenv, asdf, rvm etc.
 
 ## Clone
 

Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:3.4.6-slim-bookworm AS base
+FROM ruby:3.4.10-slim-bookworm AS base
 
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 RUN apt-get update \

Gemfile

@@ -8,12 +8,17 @@ gem "bcrypt"
 gem "chronic"
 gem "domain_name"
 gem "dotenv"
-gem "dynamic_form"
+gem "execjs"
-gem "execjs", "~> 2.7", "< 2.8"
 gem "gelf"
 gem "haml"
 gem "hashie"
 gem "highline", require: false
+# json 3.0 removed the `quirks_mode` option, which Active Support 7.2 still
+# passes in both its JSON encoder and decoder. Nothing else constrains json, so
+# without this pin Bundler resolves to 3.x and every `to_json` call raises
+# ArgumentError. Active Support dropped those calls in Rails 8.1, so this pin
+# can go when we move to 8.1.
+gem "json", "< 3"
 gem "jwt"
 gem "kaminari"
 gem "klogger-logger"
@@ -29,7 +34,7 @@ gem "ostruct"
 gem "prometheus-client"
 gem "puma"
 gem "rackup"
-gem "rails", "= 7.1.5.2"
+gem "rails", "= 7.2.3.2"
 gem "resolv"
 gem "secure_headers"
 gem "sentry-rails"
@@ -43,7 +48,7 @@ group :oidc do
   gem "omniauth-rails_csrf_protection"
 end
 
-group :development, :assets do
+group :development, :test, :assets do
   gem "coffee-rails", "~> 5.0"
   gem "jquery-rails"
   gem "sass-rails"

Gemfile.lock

@@ -2,101 +2,98 @@ GEM
   remote: https://rubygems.org/
   specs:
     abbrev (0.1.2)
-    actioncable (7.1.5.2)
+    actioncable (7.2.3.2)
-      actionpack (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
       zeitwerk (~> 2.6)
-    actionmailbox (7.1.5.2)
+    actionmailbox (7.2.3.2)
-      actionpack (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      activejob (= 7.1.5.2)
+      activejob (= 7.2.3.2)
-      activerecord (= 7.1.5.2)
+      activerecord (= 7.2.3.2)
-      activestorage (= 7.1.5.2)
+      activestorage (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
-      mail (>= 2.7.1)
+      mail (>= 2.8.0)
-      net-imap
+    actionmailer (7.2.3.2)
-      net-pop
+      actionpack (= 7.2.3.2)
-      net-smtp
+      actionview (= 7.2.3.2)
-    actionmailer (7.1.5.2)
+      activejob (= 7.2.3.2)
-      actionpack (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
-      actionview (= 7.1.5.2)
+      mail (>= 2.8.0)
-      activejob (= 7.1.5.2)
-      activesupport (= 7.1.5.2)
-      mail (~> 2.5, >= 2.5.4)
-      net-imap
-      net-pop
-      net-smtp
       rails-dom-testing (~> 2.2)
-    actionpack (7.1.5.2)
+    actionpack (7.2.3.2)
-      actionview (= 7.1.5.2)
+      actionview (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
+      cgi
       nokogiri (>= 1.8.5)
       racc
-      rack (>= 2.2.4)
+      rack (>= 2.2.4, < 3.3)
       rack-session (>= 1.0.1)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    actiontext (7.1.5.2)
+      useragent (~> 0.16)
-      actionpack (= 7.1.5.2)
+    actiontext (7.2.3.2)
-      activerecord (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      activestorage (= 7.1.5.2)
+      activerecord (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activestorage (= 7.2.3.2)
+      activesupport (= 7.2.3.2)
       globalid (>= 0.6.0)
       nokogiri (>= 1.8.5)
-    actionview (7.1.5.2)
+    actionview (7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       builder (~> 3.1)
+      cgi
       erubi (~> 1.11)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    activejob (7.1.5.2)
+    activejob (7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       globalid (>= 0.3.6)
-    activemodel (7.1.5.2)
+    activemodel (7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
-    activerecord (7.1.5.2)
+    activerecord (7.2.3.2)
-      activemodel (= 7.1.5.2)
+      activemodel (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       timeout (>= 0.4.0)
-    activestorage (7.1.5.2)
+    activestorage (7.2.3.2)
-      actionpack (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      activejob (= 7.1.5.2)
+      activejob (= 7.2.3.2)
-      activerecord (= 7.1.5.2)
+      activerecord (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       marcel (~> 1.0)
-    activesupport (7.1.5.2)
+    activesupport (7.2.3.2)
       base64
       benchmark (>= 0.3)
       bigdecimal
-      concurrent-ruby (~> 1.0, >= 1.0.2)
+      concurrent-ruby (~> 1.0, >= 1.3.1)
       connection_pool (>= 2.2.5)
       drb
       i18n (>= 1.6, < 2)
       logger (>= 1.4.2)
-      minitest (>= 5.1)
+      minitest (>= 5.1, < 6)
-      mutex_m
       securerandom (>= 0.3)
-      tzinfo (~> 2.0)
+      tzinfo (~> 2.0, >= 2.0.5)
-    addressable (2.8.6)
+    addressable (2.9.0)
-      public_suffix (>= 2.0.2, < 6.0)
+      public_suffix (>= 2.0.2, < 8.0)
     aes_key_wrap (1.1.0)
     annotate (3.2.0)
       activerecord (>= 3.2, < 8.0)
       rake (>= 10.4, < 14.0)
-    ast (2.4.2)
+    ast (2.4.3)
     attr_required (1.0.2)
     authie (5.0.0)
       activerecord (>= 6.1, < 9.0)
-    autoprefixer-rails (10.4.13.0)
+    autoprefixer-rails (10.4.21.0)
       execjs (~> 2)
     base64 (0.3.0)
-    bcrypt (3.1.20)
+    bcrypt (3.1.22)
-    benchmark (0.4.1)
+    benchmark (0.5.0)
-    bigdecimal (3.2.3)
+    bigdecimal (4.1.3)
-    bindata (2.5.0)
+    bindata (3.0.0)
-    builder (3.2.4)
+    builder (3.3.0)
+    cgi (0.5.2)
     chronic (0.10.2)
     coffee-rails (5.0.0)
       coffee-script (>= 2.2.0)
@@ -105,70 +102,74 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    concurrent-ruby (1.3.5)
+    concurrent-ruby (1.3.8)
-    connection_pool (2.5.4)
+    connection_pool (3.0.2)
-    crack (1.0.0)
+    crack (1.0.1)
       bigdecimal
       rexml
-    crass (1.0.6)
+    crass (1.0.7)
     database_cleaner-active_record (2.2.2)
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0)
-    database_cleaner-core (2.0.1)
+    database_cleaner-core (2.1.0)
-    date (3.4.1)
+    date (3.5.1)
     diff-lcs (1.6.2)
-    domain_name (0.6.20240107)
+    domain_name (0.6.20260907)
-    dotenv (3.0.2)
+    dotenv (3.2.0)
     drb (2.2.3)
-    dynamic_form (1.2.0)
+    erb (6.0.7)
-    email_validator (2.2.4)
+    erubi (1.13.1)
-      activemodel
+    execjs (2.10.2)
-    erb (5.0.2)
+      json (>= 2)
-    erubi (1.12.0)
+    factory_bot (6.6.0)
-    execjs (2.7.0)
+      activesupport (>= 6.1.0)
-    factory_bot (6.4.6)
+    factory_bot_rails (6.5.1)
-      activesupport (>= 5.0.0)
+      factory_bot (~> 6.5)
-    factory_bot_rails (6.4.3)
+      railties (>= 6.1.0)
-      factory_bot (~> 6.4)
+    faraday (2.14.3)
-      railties (>= 5.0.0)
+      faraday-net_http (>= 2.0, < 3.5)
-    faraday (2.9.0)
+      json
-      faraday-net_http (>= 2.0, < 3.2)
+      logger
-    faraday-follow_redirects (0.3.0)
+    faraday-follow_redirects (0.5.0)
       faraday (>= 1, < 3)
-    faraday-net_http (3.1.0)
+    faraday-net_http (3.4.4)
-      net-http
+      net-http (~> 0.5)
     ffi (1.15.5)
     gelf (3.1.0)
       json
-    globalid (1.3.0)
+    globalid (1.4.0)
       activesupport (>= 6.1)
-    haml (6.3.0)
+    haml (7.5.1)
+      prism (>= 1.1.0)
       temple (>= 0.8.2)
       thor
       tilt
-    hashdiff (1.1.0)
+    hashdiff (1.2.1)
-    hashie (5.0.0)
+    hashie (5.1.0)
-    highline (2.1.0)
+      logger
-    i18n (1.14.7)
+    highline (3.1.2)
+      reline
+    i18n (1.15.2)
       concurrent-ruby (~> 1.0)
-    io-console (0.8.1)
+    io-console (0.9.2)
-    irb (1.15.2)
+    irb (1.18.0)
       pp (>= 0.6.0)
+      prism (>= 1.3.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
-    jquery-rails (4.5.1)
+    jquery-rails (4.6.1)
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    json (2.7.1)
+    json (2.21.2)
-    json-jwt (1.16.6)
+    json-jwt (1.17.2)
       activesupport (>= 4.2)
       aes_key_wrap
       base64
       bindata
       faraday (~> 2.0)
       faraday-follow_redirects
-    jwt (2.8.1)
+    jwt (3.3.0)
       base64
     kaminari (1.2.2)
       activesupport (>= 4.1.0)
@@ -182,64 +183,68 @@ GEM
       activerecord
       kaminari-core (= 1.2.2)
     kaminari-core (1.2.2)
-    klogger-logger (1.4.0)
+    klogger-logger (1.5.0)
       concurrent-ruby (>= 1.0, < 2.0)
       json
       rouge (>= 3.30, < 5.0)
     konfig-config (3.0.0)
       hashie
+    language_server-protocol (3.17.0.6)
+    lint_roller (1.1.0)
     logger (1.7.0)
-    loofah (2.24.1)
+    loofah (2.25.2)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
-    mail (2.8.1)
+    mail (2.9.1)
+      logger
       mini_mime (>= 0.1.1)
       net-imap
       net-pop
       net-smtp
-    marcel (1.1.0)
+    marcel (1.2.1)
     mini_mime (1.1.5)
-    minitest (5.25.5)
+    minitest (5.27.0)
     mutex_m (0.3.0)
-    mysql2 (0.5.6)
+    mysql2 (0.5.7)
-    net-http (0.4.1)
+      bigdecimal
-      uri
+    net-http (0.9.1)
-    net-imap (0.5.11)
+      uri (>= 0.11.1)
+    net-imap (0.6.7)
       date
       net-protocol
     net-pop (0.1.2)
       net-protocol
-    net-protocol (0.2.2)
+    net-protocol (0.3.0)
       timeout
-    net-smtp (0.4.0.1)
+    net-smtp (0.5.1)
       net-protocol
     nifty-utils (1.1.7)
     nilify_blanks (1.4.0)
       activerecord (>= 4.0.0)
       activesupport (>= 4.0.0)
-    nio4r (2.7.4)
+    nio4r (2.7.5)
-    nokogiri (1.18.10-aarch64-linux-gnu)
+    nokogiri (1.19.4-aarch64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.10-arm64-darwin)
+    nokogiri (1.19.4-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.10-x86_64-darwin)
+    nokogiri (1.19.4-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.10-x86_64-linux-gnu)
+    nokogiri (1.19.4-x86_64-linux-gnu)
       racc (~> 1.4)
-    omniauth (2.1.2)
+    omniauth (2.1.4)
       hashie (>= 3.4.6)
+      logger
       rack (>= 2.2.3)
       rack-protection
-    omniauth-rails_csrf_protection (1.0.1)
+    omniauth-rails_csrf_protection (2.0.1)
       actionpack (>= 4.2)
       omniauth (~> 2.0)
-    omniauth_openid_connect (0.7.1)
+    omniauth_openid_connect (0.8.0)
       omniauth (>= 1.9, < 3)
       openid_connect (~> 2.2)
-    openid_connect (2.3.0)
+    openid_connect (2.5.0)
       activemodel
       attr_required (>= 1.0.0)
-      email_validator
       faraday (~> 2.0)
       faraday-follow_redirects
       json-jwt (>= 1.16)
@@ -250,116 +255,128 @@ GEM
       validate_url
       webfinger (~> 2.0)
     ostruct (0.6.3)
-    parallel (1.22.1)
+    parallel (2.2.0)
-    parser (3.2.1.1)
+    parser (3.3.12.0)
       ast (~> 2.4.1)
-    pp (0.6.2)
+      racc
+    pp (0.6.4)
       prettyprint
     prettyprint (0.2.0)
-    prometheus-client (4.2.2)
+    prism (1.9.0)
-    psych (5.2.6)
+    prometheus-client (5.0.0)
-      date
+      base64
-      stringio
+    public_suffix (7.0.5)
-    public_suffix (5.0.4)
+    puma (8.0.2)
-    puma (7.0.4)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (3.2.1)
+    rack (3.2.7)
-    rack-oauth2 (2.2.1)
+    rack-oauth2 (2.3.0)
       activesupport
       attr_required
       faraday (~> 2.0)
       faraday-follow_redirects
       json-jwt (>= 1.11.0)
       rack (>= 2.1.0)
-    rack-protection (4.1.1)
+    rack-protection (4.2.1)
       base64 (>= 0.1.0)
       logger (>= 1.6.0)
       rack (>= 3.0.0, < 4)
-    rack-session (2.1.1)
+    rack-session (2.1.2)
       base64 (>= 0.1.0)
       rack (>= 3.0.0)
-    rack-test (2.1.0)
+    rack-test (2.2.0)
       rack (>= 1.3)
-    rackup (2.2.1)
+    rackup (2.3.1)
       rack (>= 3)
-    rails (7.1.5.2)
+    rails (7.2.3.2)
-      actioncable (= 7.1.5.2)
+      actioncable (= 7.2.3.2)
-      actionmailbox (= 7.1.5.2)
+      actionmailbox (= 7.2.3.2)
-      actionmailer (= 7.1.5.2)
+      actionmailer (= 7.2.3.2)
-      actionpack (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      actiontext (= 7.1.5.2)
+      actiontext (= 7.2.3.2)
-      actionview (= 7.1.5.2)
+      actionview (= 7.2.3.2)
-      activejob (= 7.1.5.2)
+      activejob (= 7.2.3.2)
-      activemodel (= 7.1.5.2)
+      activemodel (= 7.2.3.2)
-      activerecord (= 7.1.5.2)
+      activerecord (= 7.2.3.2)
-      activestorage (= 7.1.5.2)
+      activestorage (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
       bundler (>= 1.15.0)
-      railties (= 7.1.5.2)
+      railties (= 7.2.3.2)
-    rails-dom-testing (2.2.0)
+    rails-dom-testing (2.3.0)
       activesupport (>= 5.0.0)
       minitest
       nokogiri (>= 1.6)
-    rails-html-sanitizer (1.6.2)
+    rails-html-sanitizer (1.7.1)
-      loofah (~> 2.21)
+      loofah (~> 2.25, >= 2.25.2)
       nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    railties (7.1.5.2)
+    railties (7.2.3.2)
-      actionpack (= 7.1.5.2)
+      actionpack (= 7.2.3.2)
-      activesupport (= 7.1.5.2)
+      activesupport (= 7.2.3.2)
-      irb
+      cgi
+      irb (~> 1.13)
       rackup (>= 1.0.0)
       rake (>= 12.2)
       thor (~> 1.0, >= 1.2.2)
+      tsort (>= 0.2)
       zeitwerk (~> 2.6)
     rainbow (3.1.1)
-    rake (13.1.0)
+    rake (13.4.2)
-    rdoc (6.14.2)
+    rbs (4.2.0)
+      logger
+      prism (>= 1.6.0)
+      tsort
+    rdoc (8.0.0)
       erb
-      psych (>= 4.0.0)
+      prism (>= 1.6.0)
-    regexp_parser (2.7.0)
+      rbs (>= 4.0.0)
-    reline (0.6.2)
+      tsort
+    regexp_parser (2.12.0)
+    reline (0.7.0)
       io-console (~> 0.5)
-    resolv (0.6.2)
+    resolv (0.7.2)
     rexml (3.4.4)
-    rouge (4.2.0)
+    rouge (4.7.0)
-    rspec (3.13.1)
+    rspec (3.13.2)
       rspec-core (~> 3.13.0)
       rspec-expectations (~> 3.13.0)
       rspec-mocks (~> 3.13.0)
-    rspec-core (3.13.5)
+    rspec-core (3.13.6)
       rspec-support (~> 3.13.0)
     rspec-expectations (3.13.5)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
-    rspec-mocks (3.13.5)
+    rspec-mocks (3.13.8)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
-    rspec-rails (6.1.1)
+    rspec-rails (8.0.4)
-      actionpack (>= 6.1)
+      actionpack (>= 7.2)
-      activesupport (>= 6.1)
+      activesupport (>= 7.2)
-      railties (>= 6.1)
+      railties (>= 7.2)
-      rspec-core (~> 3.12)
+      rspec-core (>= 3.13.0, < 5.0.0)
-      rspec-expectations (~> 3.12)
+      rspec-expectations (>= 3.13.0, < 5.0.0)
-      rspec-mocks (~> 3.12)
+      rspec-mocks (>= 3.13.0, < 5.0.0)
-      rspec-support (~> 3.12)
+      rspec-support (>= 3.13.0, < 5.0.0)
-    rspec-support (3.13.6)
+    rspec-support (3.13.7)
-    rubocop (1.48.1)
+    rubocop (1.91.0)
-      json (~> 2.3)
+      json (>= 2.3)
-      parallel (~> 1.10)
+      language_server-protocol (~> 3.17.0.2)
-      parser (>= 3.2.0.0)
+      lint_roller (~> 1.1.0)
+      parallel (>= 1.10)
+      parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.8, < 3.0)
+      regexp_parser (>= 2.9.3, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
-      rubocop-ast (>= 1.26.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 2.4.0, < 3.0)
+      unicode-display_width (>= 2.4.0, < 4.0)
-    rubocop-ast (1.27.0)
+    rubocop-ast (1.50.0)
-      parser (>= 3.2.1.0)
+      parser (>= 3.3.7.2)
-    rubocop-rails (2.18.0)
+      prism (~> 1.7)
+    rubocop-rails (2.37.0)
       activesupport (>= 4.2.0)
+      lint_roller (~> 1.1)
       rack (>= 1.1)
-      rubocop (>= 1.33.0, < 2.0)
+      rubocop (>= 1.89.0, < 2.0)
+      rubocop-ast (>= 1.44.0, < 2.0)
     ruby-progressbar (1.13.0)
     sass-rails (6.0.0)
       sassc-rails (~> 2.1, >= 2.1.1)
@@ -371,42 +388,49 @@ GEM
       sprockets (> 3.0)
       sprockets-rails
       tilt
-    secure_headers (6.5.0)
+    secure_headers (7.3.0)
+      cgi (>= 0.1)
     securerandom (0.4.1)
-    sentry-rails (5.16.1)
+    sentry-rails (7.0.0)
-      railties (>= 5.0)
+      railties (>= 5.2.0)
-      sentry-ruby (~> 5.16.1)
+      sentry-ruby (~> 7.0.0)
-    sentry-ruby (5.16.1)
+    sentry-ruby (7.0.0)
+      bigdecimal
       concurrent-ruby (~> 1.0, >= 1.0.2)
-    shoulda-matchers (6.1.0)
+      logger
-      activesupport (>= 5.2.0)
+    shoulda-matchers (8.0.1)
-    sprockets (4.2.0)
+      activesupport (>= 7.2)
-      concurrent-ruby (~> 1.0)
+    sprockets (4.4.1)
+      concurrent-ruby (~> 1.1)
+      logger
       rack (>= 2.2.4, < 4)
-    sprockets-rails (3.4.2)
+    sprockets-rails (3.5.2)
-      actionpack (>= 5.2)
+      actionpack (>= 6.1)
-      activesupport (>= 5.2)
+      activesupport (>= 6.1)
       sprockets (>= 3.0.0)
-    stringio (3.1.7)
     swd (2.0.3)
       activesupport (>= 3)
       attr_required (>= 0.0.5)
       faraday (~> 2.0)
       faraday-follow_redirects
-    temple (0.10.3)
+    temple (0.10.7)
-    thor (1.3.0)
+    thor (1.5.0)
-    tilt (2.3.0)
+    tilt (2.9.0)
-    timecop (0.9.8)
+    timecop (0.9.11)
-    timeout (0.4.3)
+    timeout (0.6.1)
+    tsort (0.2.0)
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
-    uglifier (4.2.0)
+    uglifier (4.2.1)
       execjs (>= 0.3.0, < 3)
-    unicode-display_width (2.4.2)
+    unicode-display_width (3.2.0)
-    uri (1.0.3)
+      unicode-emoji (~> 4.1)
+    unicode-emoji (4.2.0)
+    uri (1.1.1)
+    useragent (0.16.11)
     validate_url (1.0.15)
       activemodel (>= 3.0.0)
       public_suffix
@@ -414,16 +438,16 @@ GEM
       activesupport
       faraday (~> 2.0)
       faraday-follow_redirects
-    webmock (3.20.0)
+    webmock (3.26.4)
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
-    webrick (1.9.1)
+    webrick (1.9.2)
-    websocket-driver (0.8.0)
+    websocket-driver (0.8.2)
       base64
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
-    zeitwerk (2.6.13)
+    zeitwerk (2.8.3)
 
 PLATFORMS
   aarch64-linux
@@ -442,14 +466,14 @@ DEPENDENCIES
   database_cleaner-active_record
   domain_name
   dotenv
-  dynamic_form
+  execjs
-  execjs (~> 2.7, < 2.8)
   factory_bot_rails
   gelf
   haml
   hashie
   highline
   jquery-rails
+  json (< 3)
   jwt
   kaminari
   klogger-logger
@@ -467,7 +491,7 @@ DEPENDENCIES
   prometheus-client
   puma
   rackup
-  rails (= 7.1.5.2)
+  rails (= 7.2.3.2)
   resolv
   rspec
   rspec-rails

SECURITY.md

@@ -11,5 +11,5 @@ We only support updates to the 3.x versions of Postal.
 
 ## Reporting a Vulnerability
 
-If you discover a vulnerability in Postal, please do not post an issue on GitHub. Instead you should send an
+If you discover a vulnerability in Postal, please do not post an issue on GitHub. Please,
-e-mail to security@postalserver.io with details. We will get back to you directly.
+instead, [create a new security advisory through GitHub](https://github.com/postalserver/postal/security/advisories/new).

app/assets/stylesheets/application/components/_error_explanation.scss

@@ -9,14 +9,6 @@
   line-height:1.5;
 }
 
-.errorExplanation h2 {
-  display:none;
-}
-
-.errorExplanation p {
-  display:none;
-}
-
 .errorExplanation ul li {
   list-style:disc;
   margin-left:20px;

app/controllers/legacy_api/messages_controller.rb

@@ -15,12 +15,9 @@ module LegacyAPI
     #                   OR an error if the message does not exist.
     #
     def message
-      if api_params["id"].blank?
+      message = find_message
-        render_parameter_error "`id` parameter is required but is missing"
+      return if performed?
-        return
-      end
 
-      message = @current_credential.server.message(api_params["id"])
       message_hash = { id: message.id, token: message.token }
       expansions = api_params["_expansions"]
 
@@ -111,12 +108,9 @@ module LegacyAPI
     #                   OR an error if the message does not exist.
     #
     def deliveries
-      if api_params["id"].blank?
+      message = find_message
-        render_parameter_error "`id` parameter is required but is missing"
+      return if performed?
-        return
-      end
 
-      message = @current_credential.server.message(api_params["id"])
       deliveries = message.deliveries.map do |d|
         {
           id: d.id,
@@ -136,5 +130,37 @@ module LegacyAPI
                    id: api_params["id"]
     end
 
+    private
+
+    # Look up the message referenced by the request's `id` parameter.
+    #
+    # The legacy API only ever identifies a message by its integer ID. The
+    # request body is parsed as JSON, so without validation a JSON object or
+    # array supplied for `id` would arrive as a Ruby Hash/Array and be passed
+    # straight through to the message database as a raw set of SQL conditions.
+    # We therefore reject anything that is not a simple scalar before it can
+    # reach the database and coerce the value to an integer ID.
+    #
+    # Renders an error and returns nil when the parameter is missing or is not
+    # a scalar; otherwise returns the matched message (raising NotFound when no
+    # message matches, which the actions rescue).
+    #
+    # @return [Postal::MessageDB::Message, nil]
+    def find_message
+      id = api_params["id"]
+
+      if id.blank?
+        render_parameter_error "`id` parameter is required but is missing"
+        return
+      end
+
+      unless id.is_a?(String) || id.is_a?(Integer)
+        render_parameter_error "`id` parameter must be a string or integer"
+        return
+      end
+
+      @current_credential.server.message(id.to_i)
+    end
+
   end
 end

app/helpers/error_messages_helper.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ErrorMessagesHelper
+
+  # Renders a record's validation errors.
+  #
+  # This replaces the helper of the same name from the dynamic_form gem, which
+  # is unmaintained and cannot be installed on Ruby 3.4. The markup matches what
+  # that gem produced, minus the heading and description which the
+  # errorExplanation styles have always hidden, and matches the structure
+  # ajax.coffee builds when it renders errors from a remote form.
+  def error_messages_for(record)
+    record = record.to_model if record.respond_to?(:to_model)
+    return "".html_safe if record.nil? || record.errors.empty?
+
+    items = safe_join(record.errors.full_messages.map { |message| tag.li(message) })
+    tag.div(tag.ul(items), id: "errorExplanation", class: "errorExplanation")
+  end
+
+end

app/models/credential.rb

@@ -31,7 +31,7 @@ class Credential < ApplicationRecord
   validate :validate_key_cannot_be_changed
   validate :validate_key_for_smtp_ip
 
-  serialize :options, type: Hash
+  serialize :options, type: Hash, coder: YAML
 
   before_validation :generate_key
 

app/models/http_endpoint.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "uri"
+
 # == Schema Information
 #
 # Table name: http_endpoints
@@ -38,6 +40,7 @@ class HTTPEndpoint < ApplicationRecord
 
   validates :name, presence: true
   validates :url, presence: true
+  validate :url_must_be_http_or_https
   validates :encoding, inclusion: { in: ENCODINGS }
   validates :format, inclusion: { in: FORMATS }
   validates :timeout, numericality: { greater_than_or_equal_to: 5, less_than_or_equal_to: 60 }
@@ -56,4 +59,17 @@ class HTTPEndpoint < ApplicationRecord
     routes.each { |r| r.update(endpoint: nil, mode: "Reject") }
   end
 
+  private
+
+  def url_must_be_http_or_https
+    return if url.blank?
+
+    uri = URI.parse(url)
+    return if uri.is_a?(URI::HTTP) && uri.host.present?
+
+    errors.add(:url, "must be an HTTP or HTTPS URL")
+  rescue URI::InvalidURIError
+    errors.add(:url, "must be a valid HTTP or HTTPS URL")
+  end
+
 end

app/models/webhook_request.rb

@@ -34,7 +34,7 @@ class WebhookRequest < ApplicationRecord
   validates :url, presence: true
   validates :event, presence: true
 
-  serialize :payload, type: Hash
+  serialize :payload, type: Hash, coder: YAML
 
   class << self
 

config/environments/test.rb

@@ -25,7 +25,7 @@ Rails.application.configure do
   config.action_controller.perform_caching = false
 
   # Raise exceptions instead of rendering exception templates.
-  config.action_dispatch.show_exceptions = false
+  config.action_dispatch.show_exceptions = :none
 
   # Disable request forgery protection in test environment.
   config.action_controller.allow_forgery_protection = false

config/initializers/form_builder_extensions.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+# Provides `f.error_messages` on form builders. This used to come from the
+# dynamic_form gem - see ErrorMessagesHelper for why that was removed.
+ActiveSupport.on_load(:action_view) do
+  ActionView::Helpers::FormBuilder.class_eval do
+    def error_messages
+      @template.error_messages_for(@object)
+    end
+  end
+end

config/initializers/new_framework_defaults_7_0.rb

@@ -1,142 +0,0 @@
-# frozen_string_literal: true
-# Be sure to restart your server when you modify this file.
-#
-# This file eases your Rails 7.0 framework defaults upgrade.
-#
-# Uncomment each configuration one by one to switch to the new default.
-# Once your application is ready to run with all new defaults, you can remove
-# this file and set the `config.load_defaults` to `7.0`.
-#
-# Read the Guide for Upgrading Ruby on Rails for more info on each option.
-# https://guides.rubyonrails.org/upgrading_ruby_on_rails.html
-
-# `button_to` view helper will render `<button>` element, regardless of whether
-# or not the content is passed as the first argument or as a block.
-# Rails.application.config.action_view.button_to_generates_button_tag = true
-
-# `stylesheet_link_tag` view helper will not render the media attribute by default.
-# Rails.application.config.action_view.apply_stylesheet_media_default = false
-
-# Change the digest class for the key generators to `OpenSSL::Digest::SHA256`.
-# Changing this default means invalidate all encrypted messages generated by
-# your application and, all the encrypted cookies. Only change this after you
-# rotated all the messages using the key rotator.
-#
-# See upgrading guide for more information on how to build a rotator.
-# https://guides.rubyonrails.org/v7.0/upgrading_ruby_on_rails.html
-# Rails.application.config.active_support.key_generator_hash_digest_class = OpenSSL::Digest::SHA256
-
-# Change the digest class for ActiveSupport::Digest.
-# Changing this default means that for example Etags change and
-# various cache keys leading to cache invalidation.
-# Rails.application.config.active_support.hash_digest_class = OpenSSL::Digest::SHA256
-
-# Don't override ActiveSupport::TimeWithZone.name and use the default Ruby
-# implementation.
-# Rails.application.config.active_support.remove_deprecated_time_with_zone_name = true
-
-# Calls `Rails.application.executor.wrap` around test cases.
-# This makes test cases behave closer to an actual request or job.
-# Several features that are normally disabled in test, such as Active Record query cache
-# and asynchronous queries will then be enabled.
-# Rails.application.config.active_support.executor_around_test_case = true
-
-# Set both the `:open_timeout` and `:read_timeout` values for `:smtp` delivery method.
-# Rails.application.config.action_mailer.smtp_timeout = 5
-
-# The ActiveStorage video previewer will now use scene change detection to generate
-# better preview images (rather than the previous default of using the first frame
-# of the video).
-# Rails.application.config.active_storage.video_preview_arguments =
-#   "-vf 'select=eq(n\\,0)+eq(key\\,1)+gt(scene\\,0.015),loop=loop=-1:size=2,trim=start_frame=1' -frames:v 1 -f image2"
-
-# Automatically infer `inverse_of` for associations with a scope.
-# Rails.application.config.active_record.automatic_scope_inversing = true
-
-# Raise when running tests if fixtures contained foreign key violations
-# Rails.application.config.active_record.verify_foreign_keys_for_fixtures = true
-
-# Disable partial inserts.
-# This default means that all columns will be referenced in INSERT queries
-# regardless of whether they have a default or not.
-# Rails.application.config.active_record.partial_inserts = false
-
-# Protect from open redirect attacks in `redirect_back_or_to` and `redirect_to`.
-# Rails.application.config.action_controller.raise_on_open_redirects = true
-
-# Change the variant processor for Active Storage.
-# Changing this default means updating all places in your code that
-# generate variants to use image processing macros and ruby-vips
-# operations. See the upgrading guide for detail on the changes required.
-# The `:mini_magick` option is not deprecated; it's fine to keep using it.
-# Rails.application.config.active_storage.variant_processor = :vips
-
-# Enable parameter wrapping for JSON.
-# Previously this was set in an initializer. It's fine to keep using that initializer if you've customized it.
-# To disable parameter wrapping entirely, set this config to `false`.
-# Rails.application.config.action_controller.wrap_parameters_by_default = true
-
-# Specifies whether generated namespaced UUIDs follow the RFC 4122 standard for namespace IDs provided as a
-# `String` to `Digest::UUID.uuid_v3` or `Digest::UUID.uuid_v5` method calls.
-#
-# See https://guides.rubyonrails.org/configuring.html#config-active-support-use-rfc4122-namespaced-uuids for
-# more information.
-# Rails.application.config.active_support.use_rfc4122_namespaced_uuids = true
-
-# Change the default headers to disable browsers' flawed legacy XSS protection.
-# Rails.application.config.action_dispatch.default_headers = {
-#   "X-Frame-Options" => "SAMEORIGIN",
-#   "X-XSS-Protection" => "0",
-#   "X-Content-Type-Options" => "nosniff",
-#   "X-Download-Options" => "noopen",
-#   "X-Permitted-Cross-Domain-Policies" => "none",
-#   "Referrer-Policy" => "strict-origin-when-cross-origin"
-# }
-
-# ** Please read carefully, this must be configured in config/application.rb **
-# Change the format of the cache entry.
-# Changing this default means that all new cache entries added to the cache
-# will have a different format that is not supported by Rails 6.1 applications.
-# Only change this value after your application is fully deployed to Rails 7.0
-# and you have no plans to rollback.
-# When you're ready to change format, add this to `config/application.rb` (NOT this file):
-#  config.active_support.cache_format_version = 7.0
-
-# Cookie serializer: 2 options
-#
-# If you're upgrading and haven't set `cookies_serializer` previously, your cookie serializer
-# is `:marshal`. The default for new apps is `:json`.
-#
-# Rails.application.config.action_dispatch.cookies_serializer = :json
-#
-#
-# To migrate an existing application to the `:json` serializer, use the `:hybrid` option.
-#
-# Rails transparently deserializes existing (Marshal-serialized) cookies on read and
-# re-writes them in the JSON format.
-#
-# It is fine to use `:hybrid` long term; you should do that until you're confident *all* your cookies
-# have been converted to JSON. To keep using `:hybrid` long term, move this config to its own
-# initializer or to `config/application.rb`.
-#
-# Rails.application.config.action_dispatch.cookies_serializer = :hybrid
-#
-#
-# If your cookies can't yet be serialized to JSON, keep using `:marshal` for backward-compatibility.
-#
-# If you have configured the serializer elsewhere, you can remove this section of the file.
-#
-# See https://guides.rubyonrails.org/action_controller_overview.html#cookies for more information.
-
-# Change the return value of `ActionDispatch::Request#content_type` to the Content-Type header without modification.
-# Rails.application.config.action_dispatch.return_only_request_media_type_on_content_type = false
-
-# Active Storage `has_many_attached` relationships will default to replacing the current collection instead of appending to it.
-# Thus, to support submitting an empty collection, the `file_field` helper will render an hidden field `include_hidden` by default when `multiple_file_field_include_hidden` is set to `true`.
-# See https://guides.rubyonrails.org/configuring.html#config-active-storage-multiple-file-field-include-hidden for more information.
-# Rails.application.config.active_storage.multiple_file_field_include_hidden = true
-
-# ** Please read carefully, this must be configured in config/application.rb (NOT this file) **
-# Disables the deprecated #to_s override in some Ruby core classes
-# See https://guides.rubyonrails.org/configuring.html#config-active-support-disable-to-s-conversion for more information.
-# config.active_support.disable_to_s_conversion = true

config/initializers/new_framework_defaults_7_1.rb

@@ -0,0 +1,200 @@
+# frozen_string_literal: true
+
+# Be sure to restart your server when you modify this file.
+#
+# This file eases your Rails 7.1 framework defaults upgrade.
+#
+# Uncomment each configuration one by one to switch to the new default.
+# Once your application is ready to run with all new defaults, you can remove
+# this file and set the `config.load_defaults` to `7.1`.
+#
+# Read the Guide for Upgrading Ruby on Rails for more info on each option.
+# https://guides.rubyonrails.org/upgrading_ruby_on_rails.html
+
+###
+# No longer add autoloaded paths into `$LOAD_PATH`. This means that you won't be able
+# to manually require files that are managed by the autoloader, which you shouldn't do anyway.
+#
+# This will reduce the size of the load path, making `require` faster if you don't use bootsnap, or reduce the size
+# of the bootsnap cache if you use it.
+#++
+# Rails.application.config.add_autoload_paths_to_load_path = false
+
+###
+# Remove the default X-Download-Options header since it is used only by Internet Explorer.
+# If you need to support Internet Explorer, add back `"X-Download-Options" => "noopen"`.
+#++
+# Rails.application.config.action_dispatch.default_headers = {
+#   "X-Frame-Options" => "SAMEORIGIN",
+#   "X-XSS-Protection" => "0",
+#   "X-Content-Type-Options" => "nosniff",
+#   "X-Permitted-Cross-Domain-Policies" => "none",
+#   "Referrer-Policy" => "strict-origin-when-cross-origin"
+# }
+
+###
+# Do not treat an `ActiveSupport::Duration` as a number of seconds when it is
+# used as a cache expiry. Raise instead, because the intent is ambiguous.
+#++
+# Rails.application.config.active_support.raise_on_invalid_cache_expiration_time = true
+
+###
+# Specify the default serializer used by `MessageEncryptor` and `MessageVerifier`
+# instances.
+#
+# The legacy default is `:marshal`, which is a potential vector for
+# deserialization attacks in cases where a message signing secret has been
+# leaked.
+#
+# In Rails 7.1, the new default is `:json_allow_marshal`, which serializes and
+# deserializes with `ActiveSupport::JSON`, but can fall back to deserializing
+# with `Marshal` so that legacy messages can still be read.
+#
+# In Rails 7.2, the default will become `:json`, which serializes and
+# deserializes with `ActiveSupport::JSON` only.
+#
+# Alternatively, you can choose `:message_pack` or `:message_pack_allow_marshal`,
+# which serialize with `ActiveSupport::MessagePack`. `ActiveSupport::MessagePack`
+# can roundtrip some Ruby types that are not supported by JSON, and may provide
+# improved performance, but it requires the `msgpack` gem.
+#
+# For more information, see
+# https://guides.rubyonrails.org/v7.1/configuring.html#config-active-support-message-serializer
+#
+# NOTE: Changing this affects the session cookie and any other signed or
+# encrypted message. Deploy `:json_allow_marshal` everywhere before considering
+# `:json`, and be aware that rolling back to a version which cannot read the new
+# format will invalidate existing sessions.
+#++
+# Rails.application.config.active_support.message_serializer = :json_allow_marshal
+
+###
+# Enable a performance optimization that serializes message data and metadata
+# together. This changes the message format, so messages serialized this way
+# cannot be read by older versions of Rails. However, messages that use the old
+# format can still be read, regardless of whether this optimization is enabled.
+#
+# To perform a rolling deploy of a Rails 7.1 upgrade, wherein servers that have
+# not yet been upgraded must be able to read messages from upgraded servers, leave
+# this optimization off on the first deploy, then enable it on a subsequent deploy.
+#++
+# Rails.application.config.active_support.use_message_serializer_for_metadata = true
+
+###
+# Set the maximum size for Rails log files.
+#
+# `config.load_defaults "7.1"` does not set this value for environments other than
+# development and test.
+#++
+# if Rails.env.local?
+#   Rails.application.config.log_file_size = 100 * 1024 * 1024
+# end
+
+###
+# Enable raising on assignment to attr_readonly attributes. The previous behavior
+# would allow assignment but silently not persist changes to the database.
+#++
+# Rails.application.config.active_record.raise_on_assign_to_attr_readonly = true
+
+###
+# Enable validating only parent-related columns for presence when the parent is mandatory.
+# The previous behavior was to validate the presence of the parent record, which performed an extra query
+# to get the parent every time the child record was updated, even when parent has not changed.
+#++
+# Rails.application.config.active_record.belongs_to_required_validates_foreign_key = false
+
+###
+# Enable preloading of the `before_committed!` callbacks on all records in a transaction,
+# instead of only the first copy of a record.
+#++
+# Rails.application.config.active_record.before_committed_on_all_records = true
+
+###
+# Disable deprecated singular associations names.
+#++
+# Rails.application.config.active_record.allow_deprecated_singular_associations_name = false
+
+###
+# Enable running `after_commit` callbacks in the order they are defined,
+# rather than in reverse order.
+#++
+# Rails.application.config.active_record.run_after_transaction_callbacks_in_order_defined = true
+
+###
+# Run `after_commit` and `after_rollback` callbacks on the first saved instance
+# of a record in a transaction, rather than the instance which was saved last.
+#++
+# Rails.application.config.active_record.run_commit_callbacks_on_first_saved_instances_in_transaction = false
+
+###
+# Configure the query log tags to use the SQLCommenter format.
+#++
+# Rails.application.config.active_record.query_log_tags_format = :sqlcommenter
+
+###
+# Specify the default serializer used by `ActiveRecord::Base#serialize`.
+#
+# `nil` means there is no default, so every `serialize` call must declare its
+# `coder:` explicitly. This app already does that, so this option is safe to
+# enable. Do not remove those explicit coders.
+#++
+# Rails.application.config.active_record.default_column_serializer = nil
+
+###
+# Use a 7.1-compatible marshalling format when caching Active Record objects.
+#
+# This format is more efficient, but cannot be read by Rails 7.0 and earlier, so
+# do not enable this until every process is running 7.1 or later.
+#++
+# Rails.application.config.active_record.marshalling_format_version = 7.1
+
+###
+# Generate a `has_secure_token` value when the record is initialized rather than
+# when it is created.
+#++
+# Rails.application.config.active_record.generate_secure_token_on = :initialize
+
+###
+# Use a modern HTML5 sanitizer (via Nokogiri's HTML5 parser) rather than the
+# legacy HTML4 one, where it is supported.
+#
+# This changes how malformed markup is parsed and sanitized. Review anywhere the
+# application sanitizes user-supplied HTML before enabling it.
+#++
+# Rails.application.config.action_view.sanitizer_vendor = Rails::HTML::Sanitizer.best_supported_vendor
+
+###
+# Parse HTML in tests with an HTML5 parser rather than an HTML4 one.
+#++
+# Rails.application.config.dom_testing_default_html_version = :html5
+
+###
+# Precompile the filter parameters (`config.filter_parameters`) so that filtering
+# is faster at request time.
+#++
+# Rails.application.config.precompile_filter_parameters = true
+
+###
+# Log exceptions that are handled by `rescue_from` (or otherwise rendered as an
+# error page) at the `error` level rather than `fatal`.
+#++
+# Rails.application.config.action_dispatch.debug_exception_log_level = :error
+
+###
+# Change the cache entry format, so that new entries are written in a format
+# which Rails 7.0 and earlier cannot read.
+#
+# Only enable this once every process is running 7.1 or later, and you have no
+# plans to roll back.
+#++
+# Rails.application.config.active_support.cache_format_version = 7.1
+
+###
+# Use SHA-256 to derive Active Record Encryption keys and stop supporting SHA-1
+# for non-deterministic encryption.
+#
+# This app does not currently use Active Record Encryption. If that changes,
+# read the upgrade guide before enabling these.
+#++
+# Rails.application.config.active_record.encryption.hash_digest_class = OpenSSL::Digest::SHA256
+# Rails.application.config.active_record.encryption.support_sha1_for_non_deterministic_encryption = false

config/initializers/new_framework_defaults_7_2.rb

@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+# Be sure to restart your server when you modify this file.
+#
+# This file eases your Rails 7.2 framework defaults upgrade.
+#
+# Uncomment each configuration one by one to switch to the new default.
+# Once your application is ready to run with all new defaults, you can remove
+# this file and set the `config.load_defaults` to `7.2`.
+#
+# Read the Guide for Upgrading Ruby on Rails for more info on each option.
+# https://guides.rubyonrails.org/upgrading_ruby_on_rails.html
+
+###
+# Controls whether Active Job's `#perform_later` and similar methods automatically defer
+# the job queuing to after the current Active Record transaction is committed.
+#
+# Example:
+#   Topic.transaction do
+#     topic = Topic.create(...)
+#     NewTopicNotificationJob.perform_later(topic)
+#   end
+#
+# In this example, if the configuration is set to `:never`, the job will
+# be enqueued immediately, even though the `Topic` hasn't been committed yet.
+# Because of this, if the job is picked up almost immediately, or if the
+# transaction doesn't succeed for some reason, the job will fail to find this
+# topic in the database.
+#
+# If `enqueue_after_transaction_commit` is set to `:default`, the queue adapter
+# will define the behaviour.
+#
+# Note: Active Job backends can disable this feature. This is generally done by
+# backends that use the same database as Active Record as a queue, hence they
+# don't need this feature.
+#++
+# Rails.application.config.active_job.enqueue_after_transaction_commit = :default
+
+###
+# Adds image/webp to the list of content types Active Storage considers as an image
+# Prevents automatic conversion to a fallback PNG, and assumes clients support WebP, as they support gif, jpeg, and png.
+# This is possible due to broad browser support for WebP, but older browsers and email clients may still not support
+# WebP. Requires imagemagick/libvips built with WebP support.
+#++
+# Rails.application.config.active_storage.web_image_content_types = %w[image/png image/jpeg image/gif image/webp]
+
+###
+# Enable validation of migration timestamps. When set, an ActiveRecord::InvalidMigrationTimestampError
+# will be raised if the timestamp prefix for a migration is more than a day ahead of the timestamp
+# associated with the current time. This is done to prevent forward-dating of migration files, which can
+# impact migration generation and other migration commands.
+#
+# Applications with existing timestamped migrations that do not adhere to the
+# expected format can disable validation by setting this config to `false`.
+#++
+# Rails.application.config.active_record.validate_migration_timestamps = true
+
+###
+# Controls whether the PostgresqlAdapter should decode dates automatically with manual queries.
+#
+# Example:
+#   ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.select_value("select '2024-01-01'::date") #=> Date
+#
+# This query used to return a `String`.
+#++
+# Rails.application.config.active_record.postgresql_adapter_decode_dates = true
+
+###
+# Enables YJIT as of Ruby 3.3, to bring sizeable performance improvements. If you are
+# deploying to a memory constrained environment you may want to set this to `false`.
+#++
+# Rails.application.config.yjit = true

doc/config/environment-variables.md

@@ -18,6 +18,7 @@ This document contains all the environment variables which are available for thi
 | `POSTAL_SIGNING_KEY_PATH` | String | Path to the private key used for signing | $config-file-root/signing.key |
 | `POSTAL_SMTP_RELAYS` | Array of strings | An array of SMTP relays in the format of smtp://host:port | [] |
 | `POSTAL_TRUSTED_PROXIES` | Array of strings | An array of IP addresses to trust for proxying requests to Postal (in addition to localhost addresses) | [] |
+| `POSTAL_ALLOWED_REQUEST_DESTINATIONS` | Array of strings | Hostnames or IP/CIDR ranges that outbound webhook and HTTP endpoint requests are permitted to reach even when they resolve to a private, loopback, link-local or otherwise reserved address. All other such destinations are blocked to prevent SSRF. | [] |
 | `POSTAL_QUEUED_MESSAGE_LOCK_STALE_DAYS` | Integer | The number of days after which to consider a lock as stale. Messages with stale locks will be removed and not retried. | 1 |
 | `POSTAL_BATCH_QUEUED_MESSAGES` | Boolean | When enabled queued messages will be de-queued in batches based on their destination | true |
 | `WEB_SERVER_DEFAULT_PORT` | Integer | The default port the web server should listen on unless overriden by the PORT environment variable | 5000 |
@@ -42,6 +43,7 @@ This document contains all the environment variables which are available for thi
 | `LOGGING_RAILS_LOG_ENABLED` | Boolean | Enable the default Rails logger | false |
 | `LOGGING_SENTRY_DSN` | String | A DSN which should be used to report exceptions to Sentry |  |
 | `LOGGING_ENABLED` | Boolean | Enable the Postal logger to log to STDOUT | true |
+| `LOGGING_LEVEL` | String | The minimum log level for the Postal logger (debug, info, warn, error, fatal) | INFO |
 | `LOGGING_HIGHLIGHTING_ENABLED` | Boolean | Enable highlighting of log lines | false |
 | `GELF_HOST` | String | GELF-capable host to send logs to |  |
 | `GELF_PORT` | Integer | GELF port to send logs to | 12201 |

doc/config/yaml.yml

@@ -29,6 +29,8 @@ postal:
   smtp_relays: []
   # An array of IP addresses to trust for proxying requests to Postal (in addition to localhost addresses)
   trusted_proxies: []
+  # Hostnames or IP/CIDR ranges that outbound webhook and HTTP endpoint requests are permitted to reach even when they resolve to a private, loopback, link-local or otherwise reserved address. All other such destinations are blocked to prevent SSRF.
+  allowed_request_destinations: []
   # The number of days after which to consider a lock as stale. Messages with stale locks will be removed and not retried.
   queued_message_lock_stale_days: 1
   # When enabled queued messages will be de-queued in batches based on their destination
@@ -87,6 +89,8 @@ logging:
   sentry_dsn: 
   # Enable the Postal logger to log to STDOUT
   enabled: true
+  # The minimum log level for the Postal logger (debug, info, warn, error, fatal)
+  level: INFO
   # Enable highlighting of log lines
   highlighting_enabled: false
 

lib/migration_waiter.rb

@@ -15,7 +15,7 @@ class MigrationWaiter
     def wait
       attempts_remaining = ATTEMPTS
       loop do
-        pending_migrations = ActiveRecord::Base.connection.migration_context.open.pending_migrations.size
+        pending_migrations = pending_migration_count
         if pending_migrations.zero?
           Postal.logger.info "no pending migrations, continuing"
           return
@@ -33,6 +33,12 @@ class MigrationWaiter
       end
     end
 
+    # Returns the number of migrations which exist in the application but have
+    # not yet been applied to the database.
+    def pending_migration_count
+      ActiveRecord::Base.connection_pool.migration_context.open.pending_migrations.size
+    end
+
     def wait_if_appropriate
       # Don't wait if not configured
       return unless Postal::Config.migration_waiter.enabled?

lib/postal/config.rb

@@ -11,6 +11,7 @@ require "konfig/sources/environment"
 require "konfig/sources/yaml"
 require "dotenv"
 require "klogger"
+require "securerandom"
 
 require_relative "error"
 require_relative "config_schema"
@@ -82,16 +83,21 @@ module Postal
     def logger
       @logger ||= begin
         k = Klogger.new(nil, destination: Config.logging.enabled? ? $stdout : "/dev/null", highlight: Config.logging.highlighting_enabled?)
+        k.level = Config.logging.level
         k.add_destination(graylog_logging_destination) if Config.gelf.host.present?
         k
       end
     end
 
+    def process_identity
+      @process_identity ||= SecureRandom.hex(8)
+    end
+
     def process_name
       @process_name ||= begin
-        "host:#{Socket.gethostname} pid:#{Process.pid}"
+        "host:#{Socket.gethostname} pid:#{Process.pid} id:#{process_identity}"
       rescue StandardError
-        "pid:#{Process.pid}"
+        "pid:#{Process.pid} id:#{process_identity}"
       end
     end
 

lib/postal/config_schema.rb

@@ -92,6 +92,14 @@ module Postal
         transform { |ip| IPAddr.new(ip) }
       end
 
+      string :allowed_request_destinations do
+        array
+        description "Hostnames or IP/CIDR ranges that outbound webhook and HTTP " \
+                    "endpoint requests are permitted to reach even when they resolve " \
+                    "to a private, loopback, link-local or otherwise reserved address. " \
+                    "All other such destinations are blocked to prevent SSRF."
+      end
+
       integer :queued_message_lock_stale_days do
         description "The number of days after which to consider a lock as stale. Messages with stale locks will be removed and not retried."
         default 1
@@ -219,6 +227,19 @@ module Postal
         default true
       end
 
+      string :level do
+        description "The minimum log level for the Postal logger (debug, info, warn, error, fatal)"
+        default "INFO"
+        transform do |value|
+          normalized = value.to_s.strip.downcase
+          normalized = "info" if normalized.empty?
+          unless %w[debug info warn error fatal].include?(normalized)
+            raise ArgumentError, "logging.level must be one of: debug, info, warn, error, fatal (got #{value.inspect})"
+          end
+          normalized
+        end
+      end
+
       boolean :highlighting_enabled do
         description "Enable highlighting of log lines"
         default false

lib/postal/http.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "net/https"
+require "resolv"
 require "uri"
 
 module Postal
@@ -47,19 +48,24 @@ module Postal
 
       request["User-Agent"] = options[:user_agent] || "Postal/#{Postal.version}"
 
+      timeout = options[:timeout] || 60
+      ssl = uri.scheme == "https"
+
+      begin
+        Timeout.timeout(timeout) do
+          connect_address = AddressGuard.safe_connect_address(uri.host)
+
           connection = Net::HTTP.new(uri.host, uri.port)
+          # Pin the connection to the address we validated above so that the socket
+          # cannot be redirected to a different (e.g. internal) address via a DNS
+          # rebinding race between the check and the connection.
+          connection.ipaddr = connect_address
 
           if uri.scheme == "https"
             connection.use_ssl = true
             connection.verify_mode = OpenSSL::SSL::VERIFY_PEER
-        ssl = true
-      else
-        ssl = false
           end
 
-      begin
-        timeout = options[:timeout] || 60
-        Timeout.timeout(timeout) do
           result = connection.request(request)
           {
             code: result.code.to_i,
@@ -68,6 +74,13 @@ module Postal
             secure: ssl
           }
         end
+      rescue BlockedDestinationError => e
+        {
+          code: -4,
+          body: e.message,
+          headers: {},
+          secure: ssl
+        }
       rescue OpenSSL::SSL::SSLError
         {
           code: -3,
@@ -75,7 +88,7 @@ module Postal
           headers: {},
           secure: ssl
         }
-      rescue SocketError, Errno::ECONNRESET, EOFError, Errno::EINVAL, Errno::ENETUNREACH, Errno::EHOSTUNREACH, Errno::ECONNREFUSED => e
+      rescue Resolv::ResolvError, SocketError, SystemCallError, EOFError => e
         {
           code: -2,
           body: e.message,

lib/postal/http/address_guard.rb

@@ -0,0 +1,202 @@
+# frozen_string_literal: true
+
+require "ipaddr"
+require "resolv"
+require "socket"
+
+module Postal
+  module HTTP
+    # Guards outbound HTTP requests against SSRF by resolving the destination
+    # host and refusing to connect to private, loopback, link-local, multicast
+    # or otherwise reserved addresses (for example cloud metadata endpoints).
+    #
+    # Administrators can permit specific destinations by adding hostnames or
+    # IP/CIDR ranges to the `postal.allowed_request_destinations` config option.
+    class AddressGuard
+
+      # IP ranges that outbound requests are never allowed to reach unless the
+      # destination has been explicitly allowlisted.
+      BLOCKED_RANGES = [
+        # IPv4
+        "0.0.0.0/8",        # "this host on this network"
+        "10.0.0.0/8",       # RFC1918 private
+        "100.64.0.0/10",    # RFC6598 carrier-grade NAT
+        "127.0.0.0/8",      # loopback
+        "169.254.0.0/16",   # link-local (incl. 169.254.169.254 metadata)
+        "172.16.0.0/12",    # RFC1918 private
+        "192.0.0.0/24",     # IETF protocol assignments
+        "192.168.0.0/16",   # RFC1918 private
+        "198.18.0.0/15",    # benchmarking
+        "224.0.0.0/4",      # multicast
+        "240.0.0.0/4",      # reserved
+        # IPv6
+        "::/128",           # unspecified
+        "::1/128",          # loopback
+        "::ffff:0:0/96",    # IPv4-mapped (also re-checked against the v4 list)
+        "fc00::/7",         # unique-local
+        "fe80::/10",        # link-local
+        "ff00::/8", # multicast
+      ].map { |range| IPAddr.new(range) }.freeze
+
+      class << self
+
+        # Resolve and validate the given host, returning the IP address the
+        # connection should be pinned to (as a string). Pinning the connection
+        # to the validated address prevents a DNS-rebinding race between the
+        # check here and the actual connection.
+        #
+        # @param [String] host the hostname or IP literal from the request URL
+        # @raise [Postal::HTTP::BlockedDestinationError] if the host cannot be
+        #   resolved or any resolved address is not permitted
+        # @raise [SocketError] if the host only resolves to addresses whose
+        #   family this server cannot reach (e.g. IPv6 with no IPv6 support)
+        # @return [String] the validated IP address to connect to
+        def safe_connect_address(host)
+          new(host).safe_connect_address
+        end
+
+        # Whether this server has IPv6 connectivity (a global IPv6 address on
+        # one of its interfaces). Memoized as it does not change at runtime.
+        def ipv6_supported?
+          return @ipv6_supported unless @ipv6_supported.nil?
+
+          @ipv6_supported = local_families.include?(:ipv6)
+        end
+
+        # Whether this server has IPv4 connectivity. Defaults to true unless the
+        # host clearly only has IPv6, so that a host reporting no global
+        # addresses at all (e.g. inside a minimal container) still attempts IPv4
+        # as it did before this guard existed.
+        def ipv4_supported?
+          return @ipv4_supported unless @ipv4_supported.nil?
+
+          families = local_families
+          @ipv4_supported = families.include?(:ipv4) || !families.include?(:ipv6)
+        end
+
+        private
+
+        def local_families
+          families = []
+          Socket.ip_address_list.each do |address|
+            families << :ipv4 if address.ipv4? && !address.ipv4_loopback?
+            families << :ipv6 if address.ipv6? && !address.ipv6_loopback? && !address.ipv6_linklocal?
+          end
+          families.uniq
+        end
+
+      end
+
+      # @param [String] host
+      def initialize(host)
+        @host = host.to_s
+      end
+
+      def safe_connect_address
+        if @host.empty?
+          raise BlockedDestinationError, "No host was given for the request"
+        end
+
+        addresses = resolve
+        if addresses.empty?
+          raise BlockedDestinationError, "Could not resolve '#{@host}' to any IP address"
+        end
+
+        # Reject the whole request if *any* resolved address is blocked. This is
+        # checked before the reachability filtering below so that a blocked
+        # destination is always reported as such, regardless of which address
+        # families this particular server can reach. It also defeats DNS
+        # responses that mix a public and a private address to slip past.
+        addresses.each do |address|
+          next unless blocked?(address)
+
+          raise BlockedDestinationError,
+                "Destination '#{@host}' (#{address}) is not permitted"
+        end
+
+        # Only connect to an address whose family this server can actually
+        # reach. Otherwise we might pin the connection to an IPv6 address on a
+        # host without IPv6 connectivity and fail to connect even when a usable
+        # IPv4 address was available.
+        usable = addresses.select { |address| family_reachable?(address) }
+        if usable.empty?
+          raise SocketError,
+                "'#{@host}' only resolves to addresses this server cannot reach " \
+                "(#{addresses.join(', ')})"
+        end
+
+        # Prefer IPv4 for predictability; only use IPv6 when it is the only
+        # reachable option.
+        (usable.find(&:ipv4?) || usable.first).to_s
+      end
+
+      private
+
+      # @return [Array<IPAddr>]
+      def resolve
+        return [IPAddr.new(@host)] if ip_literal?
+
+        Resolv.getaddresses(@host).filter_map do |address|
+          IPAddr.new(address)
+        rescue IPAddr::InvalidAddressError
+          nil
+        end
+      end
+
+      def ip_literal?
+        IPAddr.new(@host)
+        true
+      rescue IPAddr::InvalidAddressError
+        false
+      end
+
+      # @param [IPAddr] address
+      def family_reachable?(address)
+        if address.ipv6? && !address.ipv4_mapped?
+          self.class.ipv6_supported?
+        else
+          self.class.ipv4_supported?
+        end
+      end
+
+      # @param [IPAddr] address
+      def blocked?(address)
+        return false if allowlisted?(address)
+
+        # IPv4-mapped IPv6 addresses (::ffff:a.b.c.d) must be checked against the
+        # IPv4 rules using the embedded address, otherwise they bypass the list.
+        if address.ipv6? && address.ipv4_mapped?
+          mapped = address.native
+          return true if mapped.ipv4? && BLOCKED_RANGES.any? { |range| range.include?(mapped) }
+        end
+
+        BLOCKED_RANGES.any? { |range| range.include?(address) }
+      end
+
+      # @param [IPAddr] address
+      def allowlisted?(address)
+        allowlist.any? do |entry|
+          if entry.is_a?(IPAddr)
+            entry.include?(address)
+          else
+            entry.casecmp?(@host)
+          end
+        end
+      end
+
+      # Allowlist entries are kept as strings in config. An entry that parses as
+      # an IP/CIDR is matched against the resolved address; anything else is
+      # matched against the request hostname (case-insensitively).
+      #
+      # @return [Array<IPAddr, String>]
+      def allowlist
+        @allowlist ||= Array(Postal::Config.postal.allowed_request_destinations).map do |entry|
+          IPAddr.new(entry.to_s)
+        rescue IPAddr::InvalidAddressError
+          entry.to_s
+        end
+      end
+
+    end
+  end
+end

lib/postal/http/blocked_destination_error.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Postal
+  module HTTP
+    # Raised when an outbound request would be sent to an address that is not
+    # permitted (a private, loopback, link-local or otherwise reserved address
+    # that has not been explicitly allowlisted). Used as an SSRF guard.
+    class BlockedDestinationError < StandardError
+    end
+  end
+end

lib/postal/message_db/database.rb

@@ -70,7 +70,7 @@ module Postal
       # Return the total size of all stored messages
       #
       def total_size
-        query("SELECT SUM(size) AS size FROM `#{database_name}`.`raw_message_sizes`").first["size"] || 0
+        query("SELECT SUM(size) AS size FROM #{escape_identifier(database_name)}.`raw_message_sizes`").first["size"] || 0
       end
 
       #
@@ -151,11 +151,11 @@ module Postal
         if options[:count]
           sql_query << " COUNT(id) AS count"
         elsif options[:fields]
-          sql_query << (" " + options[:fields].map { |f| "`#{f}`" }.join(", "))
+          sql_query << (" " + options[:fields].map { |f| escape_identifier(f) }.join(", "))
         else
           sql_query << " *"
         end
-        sql_query << " FROM `#{database_name}`.`#{table}`"
+        sql_query << " FROM #{escape_identifier(database_name)}.#{escape_identifier(table)}"
         if options[:where].present?
           sql_query << (" " + build_where_string(options[:where], " AND "))
         end
@@ -163,7 +163,7 @@ module Postal
           direction = (options[:direction] || "ASC").upcase
           raise Postal::Error, "Invalid direction #{options[:direction]}" unless %w[ASC DESC].include?(direction)
 
-          sql_query << " ORDER BY `#{options[:order]}` #{direction}"
+          sql_query << " ORDER BY #{escape_identifier(options[:order])} #{direction}"
         end
 
         if options[:limit]
@@ -211,7 +211,7 @@ module Postal
       # Will return the total number of affected rows.
       #
       def update(table, attributes, options = {})
-        sql_query = "UPDATE `#{database_name}`.`#{table}` SET"
+        sql_query = "UPDATE #{escape_identifier(database_name)}.#{escape_identifier(table)} SET"
         sql_query << " #{hash_to_sql(attributes)}"
         if options[:where]
           sql_query << (" " + build_where_string(options[:where]))
@@ -227,8 +227,8 @@ module Postal
       # Will return the ID of the new item.
       #
       def insert(table, attributes)
-        sql_query = "INSERT INTO `#{database_name}`.`#{table}`"
+        sql_query = "INSERT INTO #{escape_identifier(database_name)}.#{escape_identifier(table)}"
-        sql_query << (" (" + attributes.keys.map { |k| "`#{k}`" }.join(", ") + ")")
+        sql_query << (" (" + attributes.keys.map { |k| escape_identifier(k) }.join(", ") + ")")
         sql_query << (" VALUES (" + attributes.values.map { |v| escape(v) }.join(", ") + ")")
         with_mysql do |mysql|
           query_on_connection(mysql, sql_query)
@@ -243,8 +243,8 @@ module Postal
         if values.empty?
           nil
         else
-          sql_query = "INSERT INTO `#{database_name}`.`#{table}`"
+          sql_query = "INSERT INTO #{escape_identifier(database_name)}.#{escape_identifier(table)}"
-          sql_query << (" (" + keys.map { |k| "`#{k}`" }.join(", ") + ")")
+          sql_query << (" (" + keys.map { |k| escape_identifier(k) }.join(", ") + ")")
           sql_query << " VALUES "
           sql_query << values.map { |v| "(" + v.map { |r| escape(r) }.join(", ") + ")" }.join(", ")
           query(sql_query)
@@ -260,7 +260,7 @@ module Postal
       # Will return the total number of affected rows.
       #
       def delete(table, options = {})
-        sql_query = "DELETE FROM `#{database_name}`.`#{table}`"
+        sql_query = "DELETE FROM #{escape_identifier(database_name)}.#{escape_identifier(table)}"
         sql_query << (" " + build_where_string(options[:where], " AND "))
         with_mysql do |mysql|
           query_on_connection(mysql, sql_query)
@@ -351,32 +351,41 @@ module Postal
 
       def hash_to_sql(hash, joiner = ", ")
         hash.map do |key, value|
+          column = escape_identifier(key)
           if value.is_a?(Array) && value.all? { |v| v.is_a?(Integer) }
-            "`#{key}` IN (#{value.join(', ')})"
+            "#{column} IN (#{value.join(', ')})"
           elsif value.is_a?(Array)
             escaped_values = value.map { |v| escape(v) }.join(", ")
-            "`#{key}` IN (#{escaped_values})"
+            "#{column} IN (#{escaped_values})"
           elsif value.is_a?(Hash)
             sql = []
             value.each do |operator, inner_value|
               case operator
               when :less_than
-                sql << "`#{key}` < #{escape(inner_value)}"
+                sql << "#{column} < #{escape(inner_value)}"
               when :greater_than
-                sql << "`#{key}` > #{escape(inner_value)}"
+                sql << "#{column} > #{escape(inner_value)}"
               when :less_than_or_equal_to
-                sql << "`#{key}` <= #{escape(inner_value)}"
+                sql << "#{column} <= #{escape(inner_value)}"
               when :greater_than_or_equal_to
-                sql << "`#{key}` >= #{escape(inner_value)}"
+                sql << "#{column} >= #{escape(inner_value)}"
               end
             end
             sql.empty? ? "1=1" : sql.join(joiner)
           else
-            "`#{key}` = #{escape(value)}"
+            "#{column} = #{escape(value)}"
           end
         end.join(joiner)
       end
 
+      # Escape a value for safe use as a MySQL identifier (e.g. a column or
+      # table name). Identifiers are wrapped in backticks and any backtick
+      # within the identifier is doubled so it cannot break out of the quoting
+      # and inject arbitrary SQL.
+      def escape_identifier(identifier)
+        "`" + identifier.to_s.gsub("`", "``") + "`"
+      end
+
     end
   end
 end

spec/apis/legacy_api/messages/deliveries_spec.rb

@@ -64,6 +64,23 @@ RSpec.describe "Legacy Messages API", type: :request do
         end
       end
 
+      # Regression test for GHSA-x2hq-rfpg-3xr5 (see message_spec.rb). A JSON
+      # object supplied for `id` must be rejected before reaching the database
+      # rather than being interpreted as a raw set of SQL conditions.
+      context "when the message ID is a JSON object (SQL injection attempt)" do
+        it "rejects it with a parameter error and never reaches the database" do
+          expect_any_instance_of(Server).not_to receive(:message)
+          post "/api/v1/messages/deliveries",
+               headers: { "x-server-api-key" => credential.key,
+                          "content-type" => "application/json" },
+               params: { id: { "id`=0 OR SLEEP(5)#" => "x" } }.to_json
+          expect(response.status).to eq 200
+          parsed_body = JSON.parse(response.body)
+          expect(parsed_body["status"]).to eq "parameter-error"
+          expect(parsed_body["data"]["message"]).to match(/must be a string or integer/)
+        end
+      end
+
       context "when the message ID exists" do
         let(:server) { create(:server) }
         let(:credential) { create(:credential, server: server) }

spec/apis/legacy_api/messages/message_spec.rb

@@ -63,6 +63,56 @@ RSpec.describe "Legacy Messages API", type: :request do
         end
       end
 
+      # Regression tests for GHSA-x2hq-rfpg-3xr5. The request body is parsed as
+      # JSON, so a JSON object/array supplied for `id` would otherwise arrive as
+      # a Ruby Hash/Array and be passed straight through to the message database
+      # as a raw set of SQL conditions (blind SQL injection). These must be
+      # rejected before reaching the database.
+      context "when the message ID is a JSON object (SQL injection attempt)" do
+        it "rejects it with a parameter error and never reaches the database" do
+          expect_any_instance_of(Server).not_to receive(:message)
+          post "/api/v1/messages/message",
+               headers: { "x-server-api-key" => credential.key,
+                          "content-type" => "application/json" },
+               params: { id: { "id`=0 OR SLEEP(5)#" => "x" } }.to_json
+          expect(response.status).to eq 200
+          parsed_body = JSON.parse(response.body)
+          expect(parsed_body["status"]).to eq "parameter-error"
+          expect(parsed_body["data"]["message"]).to match(/must be a string or integer/)
+        end
+      end
+
+      context "when the message ID is a JSON array" do
+        it "rejects it with a parameter error" do
+          post "/api/v1/messages/message",
+               headers: { "x-server-api-key" => credential.key,
+                          "content-type" => "application/json" },
+               params: { id: [1, 2, 3] }.to_json
+          expect(response.status).to eq 200
+          parsed_body = JSON.parse(response.body)
+          expect(parsed_body["status"]).to eq "parameter-error"
+          expect(parsed_body["data"]["message"]).to match(/must be a string or integer/)
+        end
+      end
+
+      context "when the message ID is provided as a numeric string" do
+        let(:message) { MessageFactory.outgoing(server) }
+
+        it "is coerced to an integer and looks the message up" do
+          post "/api/v1/messages/message",
+               headers: { "x-server-api-key" => credential.key,
+                          "content-type" => "application/json" },
+               params: { id: message.id.to_s }.to_json
+          expect(response.status).to eq 200
+          parsed_body = JSON.parse(response.body)
+          expect(parsed_body["status"]).to eq "success"
+          expect(parsed_body["data"]).to match({
+            "id" => message.id,
+            "token" => message.token
+          })
+        end
+      end
+
       context "when the message ID exists" do
         let(:server) { create(:server) }
         let(:credential) { create(:credential, server: server) }

spec/helpers/error_messages_helper_spec.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe ErrorMessagesHelper, type: :helper do
+  describe "#error_messages_for" do
+    let(:user) { User.new }
+
+    context "when the record has no errors" do
+      it "renders nothing" do
+        expect(helper.error_messages_for(user)).to eq ""
+      end
+    end
+
+    context "when the record is nil" do
+      it "renders nothing" do
+        expect(helper.error_messages_for(nil)).to eq ""
+      end
+    end
+
+    context "when the record has errors" do
+      before do
+        user.valid?
+      end
+
+      it "renders the errorExplanation container the stylesheet targets" do
+        html = helper.error_messages_for(user)
+        expect(html).to include %(<div id="errorExplanation" class="errorExplanation">)
+      end
+
+      it "renders each full message as a list item" do
+        html = helper.error_messages_for(user)
+        user.errors.full_messages.each do |message|
+          expect(html).to include "<li>#{ERB::Util.html_escape(message)}</li>"
+        end
+      end
+
+      it "renders one list item per error" do
+        html = helper.error_messages_for(user)
+        expect(html.scan("<li>").size).to eq user.errors.count
+      end
+
+      it "returns an html_safe string" do
+        expect(helper.error_messages_for(user)).to be_html_safe
+      end
+    end
+
+    context "when an error message contains HTML" do
+      before do
+        user.errors.add(:base, %q(x'"><script>alert(1)</script>))
+      end
+
+      it "escapes it rather than emitting it verbatim" do
+        html = helper.error_messages_for(user)
+        expect(html).to_not include "<script>alert(1)</script>"
+        expect(html).to include "&lt;script&gt;alert(1)&lt;/script&gt;"
+      end
+    end
+  end
+end

spec/lib/json_encoding_spec.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+# Active Support 7.2 calls `JSON.generate(..., quirks_mode: true)` and
+# `JSON.parse(json, quirks_mode: true)`. The json gem removed `quirks_mode` in
+# 3.0, so an unpinned json resolves to 3.x and every `to_json` in the app raises
+# ArgumentError - webhook payloads and JSON API responses included. The Gemfile
+# pins json to < 3 because of this; these examples fail loudly if that pin is
+# removed before we are on a Rails version that no longer passes the option.
+RSpec.describe "JSON encoding" do
+  it "encodes a hash" do
+    expect({ "a" => 1 }.to_json).to eq '{"a":1}'
+  end
+
+  it "encodes nested structures with mixed types" do
+    payload = { "event" => "MessageSent", "timestamp" => 1.5, "payload" => { "list" => [1, "two", nil, true] } }
+    expect(JSON.parse(payload.to_json)).to eq payload
+  end
+
+  it "round trips through Active Support's encoder" do
+    payload = { "uuid" => "abc-123", "nested" => { "x" => [1, 2] } }
+    expect(ActiveSupport::JSON.decode(ActiveSupport::JSON.encode(payload))).to eq payload
+  end
+
+  it "encodes a bare value, which is what quirks_mode allowed" do
+    expect(ActiveSupport::JSON.encode("hello")).to eq '"hello"'
+    expect(ActiveSupport::JSON.encode(42)).to eq "42"
+  end
+
+  it "encodes times the way the webhook payload relies on" do
+    expect(Time.at(1_700_000_000).utc.to_f.to_json).to eq "1700000000.0"
+  end
+end

spec/lib/migration_waiter_spec.rb

@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "migration_waiter"
+
+RSpec.describe MigrationWaiter do
+  describe ".pending_migration_count" do
+    # This talks to Active Record's migration APIs directly and is the part of
+    # this class most likely to break on a Rails upgrade (the call moved from
+    # the connection to the connection pool in Rails 7.2). The rest of this
+    # class is stubbed, so this example is what actually exercises it.
+    it "returns the number of migrations which have not been applied" do
+      expect(described_class.pending_migration_count).to be_a Integer
+    end
+
+    it "returns zero when the test database is up to date" do
+      expect(described_class.pending_migration_count).to eq 0
+    end
+  end
+
+  describe ".wait" do
+    before do
+      allow(Postal.logger).to receive(:info)
+      allow(described_class).to receive(:sleep)
+    end
+
+    it "returns immediately when there are no pending migrations" do
+      allow(described_class).to receive(:pending_migration_count).and_return(0)
+      described_class.wait
+      expect(described_class).to have_received(:pending_migration_count).once
+      expect(described_class).to_not have_received(:sleep)
+    end
+
+    it "waits until there are no pending migrations remaining" do
+      allow(described_class).to receive(:pending_migration_count).and_return(2, 1, 0)
+      described_class.wait
+      expect(described_class).to have_received(:sleep).with(described_class::SLEEP_TIME).twice
+    end
+
+    it "exits when migrations are still pending after the maximum number of attempts" do
+      stub_const("#{described_class}::ATTEMPTS", 3)
+      allow(described_class).to receive(:pending_migration_count).and_return(1)
+      # Process.exit raises SystemExit for real. It has to do so here too,
+      # otherwise the wait loop never terminates.
+      allow(Process).to receive(:exit).and_raise(SystemExit)
+
+      expect { described_class.wait }.to raise_error(SystemExit)
+
+      expect(Process).to have_received(:exit).with(1)
+      expect(described_class).to have_received(:sleep).twice
+    end
+  end
+
+  describe ".wait_if_appropriate" do
+    before do
+      allow(described_class).to receive(:wait)
+      allow(described_class).to receive(:console?).and_return(false)
+      allow(described_class).to receive(:rake_task?).and_return(false)
+      allow(described_class).to receive(:rails_command?).and_return(false)
+    end
+
+    context "when the migration waiter is not enabled" do
+      it "does not wait" do
+        allow(Postal::Config.migration_waiter).to receive(:enabled?).and_return(false)
+        described_class.wait_if_appropriate
+        expect(described_class).to_not have_received(:wait)
+      end
+    end
+
+    context "when the migration waiter is enabled" do
+      before do
+        allow(Postal::Config.migration_waiter).to receive(:enabled?).and_return(true)
+      end
+
+      it "waits" do
+        described_class.wait_if_appropriate
+        expect(described_class).to have_received(:wait)
+      end
+
+      %w[console? rake_task? rails_command?].each do |predicate|
+        it "does not wait when #{predicate.delete_suffix('?')} is true" do
+          allow(described_class).to receive(predicate).and_return(true)
+          described_class.wait_if_appropriate
+          expect(described_class).to_not have_received(:wait)
+        end
+      end
+    end
+  end
+end

spec/lib/postal/http/address_guard_spec.rb

@@ -0,0 +1,192 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Postal::HTTP::AddressGuard do
+  describe ".safe_connect_address" do
+    subject(:call) { described_class.safe_connect_address(host) }
+
+    before do
+      allow(Postal::Config.postal).to receive(:allowed_request_destinations).and_return(allowlist)
+    end
+
+    let(:allowlist) { [] }
+
+    context "when given a public IP literal" do
+      let(:host) { "93.184.216.34" }
+
+      it "returns the address to connect to" do
+        expect(call).to eq "93.184.216.34"
+      end
+    end
+
+    context "when given a public IPv6 literal" do
+      let(:host) { "2606:2800:220:1:248:1893:25c8:1946" }
+
+      before { allow(described_class).to receive(:ipv6_supported?).and_return(true) }
+
+      it "returns the address to connect to" do
+        expect(call).to eq "2606:2800:220:1:248:1893:25c8:1946"
+      end
+    end
+
+    [
+      "127.0.0.1",
+      "10.0.0.1",
+      "172.16.5.4",
+      "192.168.1.1",
+      "169.254.169.254", # cloud metadata
+      "100.64.0.1",      # carrier-grade NAT
+      "0.0.0.0",
+      "::1",
+      "fd00::1",         # unique-local IPv6
+      "fe80::1",         # link-local IPv6
+      "::ffff:127.0.0.1", # IPv4-mapped loopback
+    ].each do |blocked|
+      context "when given the blocked address #{blocked}" do
+        let(:host) { blocked }
+
+        it "raises BlockedDestinationError" do
+          expect { call }.to raise_error(Postal::HTTP::BlockedDestinationError)
+        end
+      end
+    end
+
+    context "when given a hostname that resolves to a public address" do
+      let(:host) { "example.com" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return(["93.184.216.34"])
+      end
+
+      it "returns the resolved address" do
+        expect(call).to eq "93.184.216.34"
+      end
+    end
+
+    context "when given a hostname that resolves to a private address" do
+      let(:host) { "internal.example.com" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return(["10.1.2.3"])
+      end
+
+      it "raises BlockedDestinationError" do
+        expect { call }.to raise_error(Postal::HTTP::BlockedDestinationError)
+      end
+    end
+
+    context "when a hostname resolves to both a public and a private address" do
+      let(:host) { "rebind.example.com" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return(["93.184.216.34", "127.0.0.1"])
+      end
+
+      it "raises BlockedDestinationError because one address is blocked" do
+        expect { call }.to raise_error(Postal::HTTP::BlockedDestinationError)
+      end
+    end
+
+    context "when a hostname resolves to both IPv4 and IPv6 addresses" do
+      let(:host) { "dualstack.example.com" }
+      let(:ipv6) { "2606:2800:220:1:248:1893:25c8:1946" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return([ipv6, "93.184.216.34"])
+      end
+
+      context "and the server does not support IPv6" do
+        before { allow(described_class).to receive(:ipv6_supported?).and_return(false) }
+
+        it "connects over IPv4" do
+          expect(call).to eq "93.184.216.34"
+        end
+      end
+
+      context "and the server supports IPv6" do
+        before { allow(described_class).to receive(:ipv6_supported?).and_return(true) }
+
+        it "still prefers IPv4 for predictability" do
+          expect(call).to eq "93.184.216.34"
+        end
+      end
+    end
+
+    context "when a hostname resolves only to an IPv6 address" do
+      let(:host) { "v6only.example.com" }
+      let(:ipv6) { "2606:2800:220:1:248:1893:25c8:1946" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return([ipv6])
+      end
+
+      context "and the server does not support IPv6" do
+        before { allow(described_class).to receive(:ipv6_supported?).and_return(false) }
+
+        it "raises a SocketError because the address is unreachable" do
+          expect { call }.to raise_error(SocketError)
+        end
+      end
+
+      context "and the server supports IPv6" do
+        before { allow(described_class).to receive(:ipv6_supported?).and_return(true) }
+
+        it "connects over IPv6" do
+          expect(call).to eq ipv6
+        end
+      end
+    end
+
+    context "when a hostname cannot be resolved" do
+      let(:host) { "nope.example.com" }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return([])
+      end
+
+      it "raises BlockedDestinationError" do
+        expect { call }.to raise_error(Postal::HTTP::BlockedDestinationError, /resolve/)
+      end
+    end
+
+    context "when the host is blank" do
+      let(:host) { "" }
+
+      it "raises BlockedDestinationError" do
+        expect { call }.to raise_error(Postal::HTTP::BlockedDestinationError)
+      end
+    end
+
+    context "when a blocked address is allowlisted by CIDR" do
+      let(:host) { "10.0.0.5" }
+      let(:allowlist) { ["10.0.0.0/8"] }
+
+      it "returns the address" do
+        expect(call).to eq "10.0.0.5"
+      end
+    end
+
+    context "when a blocked address is allowlisted by exact IP" do
+      let(:host) { "127.0.0.1" }
+      let(:allowlist) { ["127.0.0.1"] }
+
+      it "returns the address" do
+        expect(call).to eq "127.0.0.1"
+      end
+    end
+
+    context "when a hostname resolving to a private address is allowlisted by name" do
+      let(:host) { "internal.example.com" }
+      let(:allowlist) { ["internal.example.com"] }
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with(host).and_return(["10.1.2.3"])
+      end
+
+      it "returns the resolved address" do
+        expect(call).to eq "10.1.2.3"
+      end
+    end
+  end
+end

spec/lib/postal/http_spec.rb

@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Postal::HTTP do
+  before do
+    allow(Postal::Config.postal).to receive(:allowed_request_destinations).and_return([])
+  end
+
+  describe ".post" do
+    context "when the host resolves to a blocked address" do
+      before do
+        allow(Resolv).to receive(:getaddresses).with("internal.example.com").and_return(["127.0.0.1"])
+      end
+
+      it "does not make a request and returns a blocked-destination result" do
+        result = described_class.post("http://internal.example.com/hook", json: "{}")
+        expect(result[:code]).to eq(-4)
+        expect(result[:body]).to match(/not permitted/)
+        expect(WebMock).not_to have_requested(:post, "http://internal.example.com/hook")
+      end
+    end
+
+    context "when resolving the host raises an error" do
+      before do
+        allow(Resolv).to receive(:getaddresses).with("example.com").and_raise(Resolv::ResolvError, "resolver failed")
+      end
+
+      it "returns a connection error result" do
+        result = described_class.post("http://example.com/hook", json: "{}")
+        expect(result[:code]).to eq(-2)
+        expect(result[:body]).to match(/resolver failed/)
+        expect(WebMock).not_to have_requested(:post, "http://example.com/hook")
+      end
+    end
+
+    context "when resolving the host exceeds the request timeout" do
+      before do
+        allow(Resolv).to receive(:getaddresses).with("example.com") do
+          sleep 0.2
+          ["93.184.216.34"]
+        end
+      end
+
+      it "returns a timeout result before making a request" do
+        result = described_class.post("http://example.com/hook", json: "{}", timeout: 0.05)
+        expect(result[:code]).to eq(-1)
+        expect(WebMock).not_to have_requested(:post, "http://example.com/hook")
+      end
+    end
+
+    context "when the host resolves to a public address" do
+      before do
+        allow(Resolv).to receive(:getaddresses).with("example.com").and_return(["93.184.216.34"])
+        stub_request(:post, "http://example.com/hook").to_return(status: 200, body: "OK")
+      end
+
+      it "pins the connection to the validated address and performs the request" do
+        expect_any_instance_of(Net::HTTP).to receive(:ipaddr=).with("93.184.216.34").and_call_original
+        result = described_class.post("http://example.com/hook", json: "{}")
+        expect(result[:code]).to eq(200)
+        expect(WebMock).to have_requested(:post, "http://example.com/hook")
+      end
+    end
+
+    context "when the blocked host is allowlisted" do
+      before do
+        allow(Postal::Config.postal).to receive(:allowed_request_destinations).and_return(["internal.example.com"])
+        allow(Resolv).to receive(:getaddresses).with("internal.example.com").and_return(["10.0.0.5"])
+        stub_request(:post, "http://internal.example.com/hook").to_return(status: 200, body: "OK")
+      end
+
+      it "performs the request" do
+        result = described_class.post("http://internal.example.com/hook", json: "{}")
+        expect(result[:code]).to eq(200)
+        expect(WebMock).to have_requested(:post, "http://internal.example.com/hook")
+      end
+    end
+  end
+end

spec/lib/postal/message_db/database_spec.rb

@@ -14,5 +14,64 @@ describe Postal::MessageDB::Database do
     it "should return the current schema version" do
       expect(database.schema_version).to be_a Integer
     end
+
+    describe "#escape_identifier" do
+      it "wraps a plain identifier in backticks" do
+        expect(database.send(:escape_identifier, "id")).to eq "`id`"
+      end
+
+      it "doubles embedded backticks so the value cannot break out of the quoting" do
+        expect(database.send(:escape_identifier, "id`=0 OR SLEEP(5)#"))
+          .to eq "`id``=0 OR SLEEP(5)#`"
+      end
+
+      it "coerces non-string identifiers to a string" do
+        expect(database.send(:escape_identifier, :token)).to eq "`token`"
+      end
+    end
+
+    describe "#hash_to_sql" do
+      it "builds a simple equality condition" do
+        expect(database.send(:hash_to_sql, { "id" => 5 })).to eq "`id` = '5'"
+      end
+
+      it "builds an IN condition for an array of integers" do
+        expect(database.send(:hash_to_sql, { "id" => [1, 2] })).to eq "`id` IN (1, 2)"
+      end
+
+      it "builds operator conditions for a hash value" do
+        expect(database.send(:hash_to_sql, { "id" => { greater_than: 1 } }))
+          .to eq "`id` > '1'"
+      end
+
+      # Regression tests for GHSA-x2hq-rfpg-3xr5: a backtick in the condition
+      # key must be neutralised so it cannot close the identifier quoting and
+      # inject arbitrary SQL.
+      it "neutralises a backtick injection in an equality key" do
+        sql = database.send(:hash_to_sql, { "id`=0 OR SLEEP(5)#" => "x" })
+        expect(sql).to eq "`id``=0 OR SLEEP(5)#` = 'x'"
+      end
+
+      it "neutralises a backtick injection in an IN key" do
+        sql = database.send(:hash_to_sql, { "id`)#" => %w[a b] })
+        expect(sql).to eq "`id``)#` IN ('a', 'b')"
+      end
+
+      it "neutralises a backtick injection in an operator key" do
+        sql = database.send(:hash_to_sql, { "id`#" => { greater_than: 1 } })
+        expect(sql).to eq "`id``#` > '1'"
+      end
+    end
+
+    describe "#select with a hostile condition key" do
+      # End-to-end proof against the live test database: the injected key is
+      # treated as a single (non-existent) column identifier, so MySQL rejects
+      # the query instead of executing the injected SQL.
+      it "does not allow SQL injection via the condition key" do
+        expect do
+          database.select("messages", where: { "id`=0 OR 1=1#" => "x" }, limit: 1)
+        end.to raise_error(Mysql2::Error)
+      end
+    end
   end
 end

spec/models/http_endpoint_spec.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe HTTPEndpoint do
+  describe "validations" do
+    subject(:endpoint) { build(:http_endpoint, url: url) }
+
+    [
+      "https://example.com/messages/~user;v=1?token=a+b#section",
+      "http://example.com:8080/path?x=1&y=2",
+      "https://[2606:2800:220:1:248:1893:25c8:1946]/hook",
+    ].each do |valid_url|
+      context "with #{valid_url}" do
+        let(:url) { valid_url }
+
+        it "is valid" do
+          expect(endpoint).to be_valid
+        end
+      end
+    end
+
+    [
+      "ftp://example.com/hook",
+      "https:///missing-host",
+      "not a url",
+    ].each do |invalid_url|
+      context "with #{invalid_url}" do
+        let(:url) { invalid_url }
+
+        it "is invalid" do
+          expect(endpoint).not_to be_valid
+          expect(endpoint.errors[:url]).to be_present
+        end
+      end
+    end
+  end
+end

spec/models/serialized_columns_spec.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+# Active Record's serialization defaults have changed across recent Rails
+# releases (`config.active_record.default_column_serializer` becomes `nil` in
+# the 7.1 defaults, which makes an implicit coder an error rather than YAML).
+# These columns hold data written by older versions of Postal, so the on-disk
+# format has to stay YAML. These examples pin both the format and the round trip
+# so a future framework defaults bump cannot change them silently.
+RSpec.describe "serialized columns" do
+  shared_examples "a YAML serialized hash column" do |attribute|
+    let(:value) { { "string" => "value", "number" => 123, "nested" => { "a" => [1, 2] } } }
+
+    def write_raw(record, attribute, raw)
+      sql = described_class.sanitize_sql_array(
+        ["UPDATE #{described_class.table_name} SET #{attribute} = ? WHERE id = ?", raw, record.id]
+      )
+      described_class.connection.update(sql)
+    end
+
+    def read_raw(record, attribute)
+      described_class.connection.select_value(
+        described_class.sanitize_sql_array(
+          ["SELECT #{attribute} FROM #{described_class.table_name} WHERE id = ?", record.id]
+        )
+      )
+    end
+
+    it "defaults to an empty hash" do
+      expect(described_class.new.public_send(attribute)).to eq({})
+    end
+
+    it "round trips a hash through the database" do
+      record.update!(attribute => value)
+      expect(record.reload.public_send(attribute)).to eq value
+    end
+
+    it "stores the value as YAML in the database" do
+      record.update!(attribute => value)
+      raw = read_raw(record, attribute)
+
+      expect(raw).to be_a String
+      expect(YAML.safe_load(raw)).to eq value
+    end
+
+    it "reads YAML which was written by a previous version of Postal" do
+      write_raw(record, attribute, value.to_yaml)
+      expect(record.reload.public_send(attribute)).to eq value
+    end
+
+    it "rejects a value which is not a hash" do
+      expect { record.update!(attribute => "not a hash") }.to raise_error ActiveRecord::SerializationTypeMismatch
+    end
+  end
+
+  describe Credential do
+    let(:record) { create(:credential) }
+
+    include_examples "a YAML serialized hash column", :options
+  end
+
+  describe WebhookRequest do
+    let(:record) { create(:webhook_request) }
+
+    include_examples "a YAML serialized hash column", :payload
+  end
+end

spec/requests/rendering_spec.rb

@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+# These examples exist to exercise the view layer end to end - HAML, the asset
+# pipeline, the layout, form helpers and the session middleware. The rest of the
+# request specs only assert on redirects, so without these nothing in the suite
+# would notice if a Rails upgrade broke rendering.
+RSpec.describe "rendering", type: :request do
+  before do
+    host! Postal::Config.postal.web_hostname
+  end
+
+  describe "the login page" do
+    it "renders" do
+      get "/login"
+
+      expect(response).to have_http_status(:ok)
+      expect(response.media_type).to eq "text/html"
+      expect(response.body).to include "<form"
+      expect(response.body).to include "password"
+    end
+
+    it "renders the layout including compiled assets" do
+      get "/login"
+
+      expect(response.body).to include "<html"
+      expect(response.body).to match(/<link[^>]+stylesheets?/i).or match(/<link[^>]+\.css/i)
+      expect(response.body).to match(/<script[^>]+\.js/i)
+    end
+  end
+
+  describe "when not authenticated" do
+    it "redirects to the login page" do
+      get "/"
+
+      expect(response).to redirect_to("/login?return_to=%2F")
+    end
+  end
+
+  describe "when authenticated" do
+    let(:user) { create(:user) }
+
+    before do
+      post "/login", params: { email_address: user.email_address, password: "passw0rd" }
+    end
+
+    it "renders the organizations index" do
+      get "/"
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include "<html"
+    end
+
+    it "renders the user settings page" do
+      get "/settings"
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include user.email_address
+    end
+
+    # `f.error_messages` and `error_messages_for` used to come from the
+    # dynamic_form gem. The app provides them itself now (see
+    # ErrorMessagesHelper and config/initializers/form_builder_extensions.rb),
+    # so the rendered output is our responsibility to keep working.
+    describe "a form which fails validation" do
+      before do
+        patch "/settings", params: {
+          password: "passw0rd",
+          user: { first_name: "", last_name: "Smith", email_address: user.email_address }
+        }
+      end
+
+      it "re-renders the form" do
+        expect(response).to have_http_status(:ok)
+      end
+
+      it "renders the validation errors in the errorExplanation container" do
+        expect(response.body).to include %(<div id="errorExplanation" class="errorExplanation">)
+        expect(response.body).to include "<li>First name can&#39;t be blank</li>"
+      end
+    end
+
+    it "does not render an error container on a form which has no errors" do
+      get "/settings"
+
+      expect(response.body).to_not include "errorExplanation"
+    end
+  end
+end

spec/requests/security_headers_spec.rb

@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+# The security headers come from the secure_headers gem plus Rails' own
+# defaults, and both have changed them across major versions. Nothing else in
+# the suite looks at response headers, so pin them here.
+RSpec.describe "security headers", type: :request do
+  before do
+    host! Postal::Config.postal.web_hostname
+    get "/login"
+  end
+
+  it "responds successfully" do
+    expect(response).to have_http_status(:ok)
+  end
+
+  it "sets X-Frame-Options to sameorigin" do
+    expect(response.headers["x-frame-options"]).to eq "sameorigin"
+  end
+
+  it "sets X-Content-Type-Options to nosniff" do
+    expect(response.headers["x-content-type-options"]).to eq "nosniff"
+  end
+
+  it "disables the legacy XSS auditor rather than enabling it" do
+    # secure_headers 7 changed this from "1; mode=block". `0` is correct: the
+    # legacy auditor is deprecated and blocking mode was itself exploitable.
+    expect(response.headers["x-xss-protection"]).to eq "0"
+  end
+
+  it "sets X-Permitted-Cross-Domain-Policies to none" do
+    expect(response.headers["x-permitted-cross-domain-policies"]).to eq "none"
+  end
+
+  describe "the content security policy" do
+    let(:csp) { response.headers["content-security-policy"] }
+
+    it "is present" do
+      expect(csp).to be_present
+    end
+
+    it "restricts script-src to self" do
+      expect(csp).to include "script-src 'self'"
+    end
+
+    it "restricts connect-src to self" do
+      expect(csp).to include "connect-src 'self'"
+    end
+
+    it "forbids object-src" do
+      expect(csp).to include "object-src 'none'"
+    end
+  end
+
+  describe "cookies" do
+    # Rack 3 returns set-cookie as a String for one cookie and an Array for
+    # several, so normalise before looking for a particular cookie.
+    def cookie_named(name)
+      Array(response.headers["set-cookie"]).flat_map { |v| v.split("\n") }.find { |c| c.start_with?("#{name}=") }
+    end
+
+    it "marks the browser id cookie httponly and samesite lax" do
+      expect(cookie_named("browser_id")).to include "httponly"
+      expect(cookie_named("browser_id")).to include "samesite=lax"
+    end
+
+    context "once logged in" do
+      let(:user) { create(:user) }
+
+      before do
+        post "/login", params: { email_address: user.email_address, password: "passw0rd" }
+      end
+
+      it "marks the authie session cookie httponly and samesite lax" do
+        expect(cookie_named("user_session")).to include "httponly"
+        expect(cookie_named("user_session")).to include "samesite=lax"
+      end
+
+      it "marks the rails session cookie httponly and samesite lax" do
+        expect(cookie_named("_postal_session")).to include "httponly"
+        expect(cookie_named("_postal_session")).to include "samesite=lax"
+      end
+    end
+  end
+end

spec/services/webhook_delivery_service_spec.rb

@@ -13,6 +13,7 @@ RSpec.describe WebhookDeliveryService do
   let(:response_body) { "OK" }
 
   before do
+    allow(Resolv).to receive(:getaddresses).with("example.com").and_return(["93.184.216.34"])
     stub_request(:post, webhook.url).to_return(status: response_status, body: response_body)
   end
 
@@ -116,5 +117,26 @@ RSpec.describe WebhookDeliveryService do
         expect { webhook_request.reload }.to raise_error(ActiveRecord::RecordNotFound)
       end
     end
+
+    context "when the webhook URL resolves to a blocked (private) address" do
+      let(:webhook_request) do
+        create(:webhook_request, :locked, webhook: webhook, url: "http://internal.example.com/hook")
+      end
+
+      before do
+        allow(Resolv).to receive(:getaddresses).with("internal.example.com").and_return(["127.0.0.1"])
+      end
+
+      it "does not make a request to the destination" do
+        service.call
+        expect(WebMock).not_to have_requested(:post, "http://internal.example.com/hook")
+      end
+
+      it "records the failure and schedules a retry" do
+        service.call
+        expect(webhook_request.reload.attempts).to eq(1)
+        expect(webhook_request.retry_after).to be_present
+      end
+    end
   end
 end

spec/views/haml_templates_spec.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "haml"
+
+# Compiles every HAML template and checks the Ruby it produces actually parses.
+# A HAML major version bump changes the compiler, and the request specs only
+# render a handful of pages, so without this most of app/views is unverified
+# until someone visits the page in production.
+RSpec.describe "HAML templates" do
+  def compile(source)
+    # Wrapped in a method body because layouts use `yield`, which is not legal
+    # at the top level.
+    RubyVM::AbstractSyntaxTree.parse("def _template\n#{Haml::Engine.new.call(source)}\nend")
+  end
+
+  templates = Dir[Rails.root.join("app/views/**/*.haml")]
+
+  it "finds the templates to check" do
+    expect(templates.size).to be > 50
+  end
+
+  # Without this, a change in how HAML reports errors could quietly turn every
+  # example below into a no-op that passes on anything.
+  describe "the check itself" do
+    it "rejects a template whose Ruby does not parse" do
+      expect { compile("= foo(\n") }.to raise_error(SyntaxError)
+    end
+
+    it "rejects a template with a malformed attribute hash" do
+      expect { compile("%div{:a =>}\n") }.to raise_error(SyntaxError)
+    end
+
+    it "accepts a valid template" do
+      expect { compile("%div\n  %p hello\n") }.to_not raise_error
+    end
+  end
+
+  templates.each do |path|
+    relative = path.sub("#{Rails.root}/", "")
+
+    it "compiles #{relative}" do
+      expect { compile(File.read(path)) }.to_not raise_error
+    end
+  end
+end