Fix ambiguous routing issues by teaching router about reserved words

8 files changed, 278 insertions, 88 deletions

diff --git a/lib/api/repositories.rb b/lib/api/repositories.rb
index 8f16e532ecb..14d2bff9cb5 100644
--- a/lib/api/repositories.rb
+++ b/lib/api/repositories.rb
@@ -85,7 +85,7 @@ module API
         optional :sha, type: String, desc: 'The commit sha of the archive to be downloaded'
         optional :format, type: String, desc: 'The archive format'
       end
-      get ':id/repository/archive', requirements: { format: Gitlab::Regex.archive_formats_regex } do
+      get ':id/repository/archive', requirements: { format: Gitlab::PathRegex.archive_formats_regex } do
         begin
           send_git_archive user_project.repository, ref: params[:sha], format: params[:format]
         rescue
diff --git a/lib/api/v3/repositories.rb b/lib/api/v3/repositories.rb
index e4d14bc8168..0eaa0de2eef 100644
--- a/lib/api/v3/repositories.rb
+++ b/lib/api/v3/repositories.rb
@@ -72,7 +72,7 @@ module API
           optional :sha, type: String, desc: 'The commit sha of the archive to be downloaded'
           optional :format, type: String, desc: 'The archive format'
         end
-        get ':id/repository/archive', requirements: { format: Gitlab::Regex.archive_formats_regex } do
+        get ':id/repository/archive', requirements: { format: Gitlab::PathRegex.archive_formats_regex } do
           begin
             send_git_archive user_project.repository, ref: params[:sha], format: params[:format]
           rescue
diff --git a/lib/constraints/group_url_constrainer.rb b/lib/constraints/group_url_constrainer.rb
index 5f379756c11..6fc1d56d7a0 100644
--- a/lib/constraints/group_url_constrainer.rb
+++ b/lib/constraints/group_url_constrainer.rb
@@ -1,9 +1,9 @@
 class GroupUrlConstrainer
   def matches?(request)
-    id = request.params[:id]
+    full_path = request.params[:group_id] || request.params[:id]
 
-    return false unless DynamicPathValidator.valid?(id)
+    return false unless DynamicPathValidator.valid_group_path?(full_path)
 
-    Group.find_by_full_path(id, follow_redirects: request.get?).present?
+    Group.find_by_full_path(full_path, follow_redirects: request.get?).present?
   end
 end
diff --git a/lib/constraints/project_url_constrainer.rb b/lib/constraints/project_url_constrainer.rb
index 6f542f63f98..4c0aee6c48f 100644
--- a/lib/constraints/project_url_constrainer.rb
+++ b/lib/constraints/project_url_constrainer.rb
@@ -2,9 +2,9 @@ class ProjectUrlConstrainer
   def matches?(request)
     namespace_path = request.params[:namespace_id]
     project_path = request.params[:project_id] || request.params[:id]
-    full_path = namespace_path + '/' + project_path
+    full_path = [namespace_path, project_path].join('/')
 
-    return false unless DynamicPathValidator.valid?(full_path)
+    return false unless DynamicPathValidator.valid_project_path?(full_path)
 
     Project.find_by_full_path(full_path, follow_redirects: request.get?).present?
   end
diff --git a/lib/constraints/user_url_constrainer.rb b/lib/constraints/user_url_constrainer.rb
index 28159dc0dec..d16ae7f3f40 100644
--- a/lib/constraints/user_url_constrainer.rb
+++ b/lib/constraints/user_url_constrainer.rb
@@ -1,5 +1,9 @@
 class UserUrlConstrainer
   def matches?(request)
-    User.find_by_full_path(request.params[:username], follow_redirects: request.get?).present?
+    full_path = request.params[:username]
+
+    return false unless DynamicPathValidator.valid_user_path?(full_path)
+
+    User.find_by_full_path(full_path, follow_redirects: request.get?).present?
   end
 end
diff --git a/lib/gitlab/etag_caching/router.rb b/lib/gitlab/etag_caching/router.rb
index ba31041d0c1..7d03209684a 100644
--- a/lib/gitlab/etag_caching/router.rb
+++ b/lib/gitlab/etag_caching/router.rb
@@ -10,7 +10,7 @@ module Gitlab
       #   - Ending in `issues/id`/realtime_changes` for the `issue_title` route
       USED_IN_ROUTES = %w[noteable issue notes issues realtime_changes
                           commit pipelines merge_requests new].freeze
-      RESERVED_WORDS = DynamicPathValidator::WILDCARD_ROUTES - USED_IN_ROUTES
+      RESERVED_WORDS = Gitlab::PathRegex::ILLEGAL_PROJECT_PATH_WORDS - USED_IN_ROUTES
       RESERVED_WORDS_REGEX = Regexp.union(*RESERVED_WORDS)
       ROUTES = [
         Gitlab::EtagCaching::Router::Route.new(
diff --git a/lib/gitlab/path_regex.rb b/lib/gitlab/path_regex.rb
new file mode 100644
index 00000000000..1ee0f2b3998
--- /dev/null
+++ b/lib/gitlab/path_regex.rb
@@ -0,0 +1,264 @@
+module Gitlab
+  module PathRegex
+    extend self
+
+    # All routes that appear on the top level must be listed here.
+    # This will make sure that groups cannot be created with these names
+    # as these routes would be masked by the paths already in place.
+    #
+    # Example:
+    #   /api/api-project
+    #
+    #  the path `api` shouldn't be allowed because it would be masked by `api/*`
+    #
+    TOP_LEVEL_ROUTES = %w[
+      -
+      .well-known
+      abuse_reports
+      admin
+      all
+      api
+      assets
+      autocomplete
+      ci
+      dashboard
+      explore
+      files
+      groups
+      health_check
+      help
+      hooks
+      import
+      invites
+      issues
+      jwt
+      koding
+      member
+      merge_requests
+      new
+      notes
+      notification_settings
+      oauth
+      profile
+      projects
+      public
+      repository
+      robots.txt
+      s
+      search
+      sent_notifications
+      services
+      snippets
+      teams
+      u
+      unicorn_test
+      unsubscribes
+      uploads
+      users
+    ].freeze
+
+    # This list should contain all words following `/*namespace_id/:project_id` in
+    # routes that contain a second wildcard.
+    #
+    # Example:
+    #   /*namespace_id/:project_id/badges/*ref/build
+    #
+    # If `badges` was allowed as a project/group name, we would not be able to access the
+    # `badges` route for those projects:
+    #
+    # Consider a namespace with path `foo/bar` and a project called `badges`.
+    # The route to the build badge would then be `/foo/bar/badges/badges/master/build.svg`
+    #
+    # When accessing this path the route would be matched to the `badges` path
+    # with the following params:
+    #   - namespace_id: `foo`
+    #   - project_id: `bar`
+    #   - ref: `badges/master`
+    #
+    # Failing to find the project, this would result in a 404.
+    #
+    # By rejecting `badges` the router can _count_ on the fact that `badges` will
+    # be preceded by the `namespace/project`.
+    PROJECT_WILDCARD_ROUTES = %w[
+      badges
+      blame
+      blob
+      builds
+      commits
+      create
+      create_dir
+      edit
+      environments/folders
+      files
+      find_file
+      gitlab-lfs/objects
+      info/lfs/objects
+      new
+      preview
+      raw
+      refs
+      tree
+      update
+      wikis
+    ].freeze
+
+    # These are all the paths that follow `/groups/*id/ or `/groups/*group_id`
+    # We need to reject these because we have a `/groups/*id` page that is the same
+    # as the `/*id`.
+    #
+    # If we would allow a subgroup to be created with the name `activity` then
+    # this group would not be accessible through `/groups/parent/activity` since
+    # this would map to the activity-page of its parent.
+    GROUP_ROUTES = %w[
+      activity
+      analytics
+      audit_events
+      avatar
+      edit
+      group_members
+      hooks
+      issues
+      labels
+      ldap
+      ldap_group_links
+      merge_requests
+      milestones
+      notification_setting
+      pipeline_quota
+      projects
+      subgroups
+    ].freeze
+
+    ILLEGAL_PROJECT_PATH_WORDS = PROJECT_WILDCARD_ROUTES
+    ILLEGAL_GROUP_PATH_WORDS = (PROJECT_WILDCARD_ROUTES | GROUP_ROUTES).freeze
+
+    # The namespace regex is used in JavaScript to validate usernames in the "Register" form. However, Javascript
+    # does not support the negative lookbehind assertion (?<!) that disallows usernames ending in `.git` and `.atom`.
+    # Since this is a non-trivial problem to solve in Javascript (heavily complicate the regex, modify view code to
+    # allow non-regex validations, etc), `NAMESPACE_FORMAT_REGEX_JS` serves as a Javascript-compatible version of
+    # `NAMESPACE_FORMAT_REGEX`, with the negative lookbehind assertion removed. This means that the client-side validation
+    # will pass for usernames ending in `.atom` and `.git`, but will be caught by the server-side validation.
+    PATH_REGEX_STR = '[a-zA-Z0-9_\.][a-zA-Z0-9_\-\.]*'.freeze
+    NAMESPACE_FORMAT_REGEX_JS = PATH_REGEX_STR + '[a-zA-Z0-9_\-]|[a-zA-Z0-9_]'.freeze
+
+    NO_SUFFIX_REGEX = /(?<!\.git|\.atom)/.freeze
+    NAMESPACE_FORMAT_REGEX = /(?:#{NAMESPACE_FORMAT_REGEX_JS})#{NO_SUFFIX_REGEX}/.freeze
+    PROJECT_PATH_FORMAT_REGEX = /(?:#{PATH_REGEX_STR})#{NO_SUFFIX_REGEX}/.freeze
+    FULL_NAMESPACE_FORMAT_REGEX = %r{(#{NAMESPACE_FORMAT_REGEX}/)*#{NAMESPACE_FORMAT_REGEX}}.freeze
+
+    def root_namespace_route_regex
+      @root_namespace_route_regex ||= begin
+        illegal_words = Regexp.new(Regexp.union(TOP_LEVEL_ROUTES).source, Regexp::IGNORECASE)
+
+        single_line_regexp %r{
+          (?!(#{illegal_words})/)
+          #{NAMESPACE_FORMAT_REGEX}
+        }x
+      end
+    end
+
+    def full_namespace_route_regex
+      @full_namespace_route_regex ||= begin
+        illegal_words = Regexp.new(Regexp.union(ILLEGAL_GROUP_PATH_WORDS).source, Regexp::IGNORECASE)
+
+        single_line_regexp %r{
+          #{root_namespace_route_regex}
+          (?:
+            /
+            (?!#{illegal_words}/)
+            #{NAMESPACE_FORMAT_REGEX}
+          )*
+        }x
+      end
+    end
+
+    def project_route_regex
+      @project_route_regex ||= begin
+        illegal_words = Regexp.new(Regexp.union(ILLEGAL_PROJECT_PATH_WORDS).source, Regexp::IGNORECASE)
+
+        single_line_regexp %r{
+          (?!(#{illegal_words})/)
+          #{PROJECT_PATH_FORMAT_REGEX}
+        }x
+      end
+    end
+
+    def project_git_route_regex
+      @project_git_route_regex ||= /#{project_route_regex}\.git/.freeze
+    end
+
+    def root_namespace_path_regex
+      @root_namespace_path_regex ||= %r{\A#{root_namespace_route_regex}/\z}
+    end
+
+    def full_namespace_path_regex
+      @full_namespace_path_regex ||= %r{\A#{full_namespace_route_regex}/\z}
+    end
+
+    def project_path_regex
+      @project_path_regex ||= %r{\A#{project_route_regex}/\z}
+    end
+
+    def full_project_path_regex
+      @full_project_path_regex ||= %r{\A#{full_namespace_route_regex}/#{project_route_regex}/\z}
+    end
+
+    def full_namespace_format_regex
+      @namespace_format_regex ||= /A#{FULL_NAMESPACE_FORMAT_REGEX}\z/.freeze
+    end
+
+    def namespace_format_regex
+      @namespace_format_regex ||= /\A#{NAMESPACE_FORMAT_REGEX}\z/.freeze
+    end
+
+    def namespace_format_message
+      "can contain only letters, digits, '_', '-' and '.'. " \
+      "Cannot start with '-' or end in '.', '.git' or '.atom'." \
+    end
+
+    def project_path_format_regex
+      @project_path_format_regex ||= /\A#{PROJECT_PATH_FORMAT_REGEX}\z/.freeze
+    end
+
+    def project_path_format_message
+      "can contain only letters, digits, '_', '-' and '.'. " \
+      "Cannot start with '-', end in '.git' or end in '.atom'" \
+    end
+
+    def archive_formats_regex
+      #                           |zip|tar|    tar.gz    |         tar.bz2         |
+      @archive_formats_regex ||= /(zip|tar|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)/.freeze
+    end
+
+    def git_reference_regex
+      # Valid git ref regex, see:
+      # https://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html
+
+      @git_reference_regex ||= single_line_regexp %r{
+        (?!
+           (?# doesn't begins with)
+           \/|                    (?# rule #6)
+           (?# doesn't contain)
+           .*(?:
+              [\/.]\.|            (?# rule #1,3)
+              \/\/|               (?# rule #6)
+              @\{|                (?# rule #8)
+              \\                  (?# rule #9)
+           )
+        )
+        [^\000-\040\177~^:?*\[]+  (?# rule #4-5)
+        (?# doesn't end with)
+        (?<!\.lock)               (?# rule #1)
+        (?<![\/.])                (?# rule #6-7)
+      }x
+    end
+
+    private
+
+    def single_line_regexp(regex)
+      # Turns a multiline extended regexp into a single line one,
+      # beacuse `rake routes` breaks on multiline regexes.
+      Regexp.new(regex.source.gsub(/\(\?#.+?\)/ , '').gsub(/\s*/, ''), regex.options ^ Regexp::EXTENDED).freeze
+    end
+  end
+end
diff --git a/lib/gitlab/regex.rb b/lib/gitlab/regex.rb
index b7fef5dd068..e4d2a992470 100644
--- a/lib/gitlab/regex.rb
+++ b/lib/gitlab/regex.rb
@@ -2,39 +2,6 @@ module Gitlab
   module Regex
     extend self
 
-    # The namespace regex is used in Javascript to validate usernames in the "Register" form. However, Javascript
-    # does not support the negative lookbehind assertion (?<!) that disallows usernames ending in `.git` and `.atom`.
-    # Since this is a non-trivial problem to solve in Javascript (heavily complicate the regex, modify view code to
-    # allow non-regex validatiions, etc), `NAMESPACE_REGEX_STR_JS` serves as a Javascript-compatible version of
-    # `NAMESPACE_REGEX_STR`, with the negative lookbehind assertion removed. This means that the client-side validation
-    # will pass for usernames ending in `.atom` and `.git`, but will be caught by the server-side validation.
-    PATH_REGEX_STR = '[a-zA-Z0-9_\.][a-zA-Z0-9_\-\.]*'.freeze
-    NAMESPACE_REGEX_STR_JS = PATH_REGEX_STR + '[a-zA-Z0-9_\-]|[a-zA-Z0-9_]'.freeze
-    NO_SUFFIX_REGEX_STR = '(?<!\.git|\.atom)'.freeze
-    NAMESPACE_REGEX_STR = "(?:#{NAMESPACE_REGEX_STR_JS})#{NO_SUFFIX_REGEX_STR}".freeze
-    PROJECT_REGEX_STR = "(?:#{PATH_REGEX_STR})#{NO_SUFFIX_REGEX_STR}".freeze
-
-    # Same as NAMESPACE_REGEX_STR but allows `/` in the path.
-    # So `group/subgroup` will match this regex but not NAMESPACE_REGEX_STR
-    FULL_NAMESPACE_REGEX_STR = "(?:#{NAMESPACE_REGEX_STR}/)*#{NAMESPACE_REGEX_STR}".freeze
-
-    def namespace_regex
-      @namespace_regex ||= /\A#{NAMESPACE_REGEX_STR}\z/.freeze
-    end
-
-    def full_namespace_regex
-      @full_namespace_regex ||= %r{\A#{FULL_NAMESPACE_REGEX_STR}\z}
-    end
-
-    def namespace_route_regex
-      @namespace_route_regex ||= /#{NAMESPACE_REGEX_STR}/.freeze
-    end
-
-    def namespace_regex_message
-      "can contain only letters, digits, '_', '-' and '.'. " \
-      "Cannot start with '-' or end in '.', '.git' or '.atom'." \
-    end
-
     def namespace_name_regex
       @namespace_name_regex ||= /\A[\p{Alnum}\p{Pd}_\. ]*\z/.freeze
     end
@@ -52,23 +19,6 @@ module Gitlab
       "It must start with letter, digit, emoji or '_'."
     end
 
-    def project_path_regex
-      @project_path_regex ||= /\A#{PROJECT_REGEX_STR}\z/.freeze
-    end
-
-    def project_route_regex
-      @project_route_regex ||= /#{PROJECT_REGEX_STR}/.freeze
-    end
-
-    def project_git_route_regex
-      @project_route_git_regex ||= /#{PATH_REGEX_STR}\.git/.freeze
-    end
-
-    def project_path_regex_message
-      "can contain only letters, digits, '_', '-' and '.'. " \
-      "Cannot start with '-', end in '.git' or end in '.atom'" \
-    end
-
     def file_name_regex
       @file_name_regex ||= /\A[[[:alnum:]]_\-\.\@\+]*\z/.freeze
     end
@@ -77,36 +27,8 @@ module Gitlab
       "can contain only letters, digits, '_', '-', '@', '+' and '.'."
     end
 
-    def archive_formats_regex
-      #                           |zip|tar|    tar.gz    |         tar.bz2         |
-      @archive_formats_regex ||= /(zip|tar|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)/.freeze
-    end
-
-    def git_reference_regex
-      # Valid git ref regex, see:
-      # https://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html
-
-      @git_reference_regex ||= %r{
-        (?!
-           (?# doesn't begins with)
-           \/|                    (?# rule #6)
-           (?# doesn't contain)
-           .*(?:
-              [\/.]\.|            (?# rule #1,3)
-              \/\/|               (?# rule #6)
-              @\{|                (?# rule #8)
-              \\                  (?# rule #9)
-           )
-        )
-        [^\000-\040\177~^:?*\[]+  (?# rule #4-5)
-        (?# doesn't end with)
-        (?<!\.lock)               (?# rule #1)
-        (?<![\/.])                (?# rule #6-7)
-      }x.freeze
-    end
-
     def container_registry_reference_regex
-      git_reference_regex
+      Gitlab::PathRegex.git_reference_regex
     end
 
     ##