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Commit 688faaee41448c11504adb3e94ab4d63413b7ffa

Authored by Rodrigo Souto
Committed by Antonio Terceiro
1 parent 52b58187
Exists in master and in 29 other branches add_member_task_reject_details, admin_visible_profile, article-list-template, community_notifications, contact_admin_translation, event_fixes, fix_comments_pagination, fix_rails4_organization_ratings, fix_sign_up_form, follow_step_fix, forum_topic_creation, mirror_block_improvements, multi_env_on_remote_user, new_security, noosfero_spb_ci, organization_ratings_improvements, organization_ratings_link_to_profile_stable-spb-1.3, organization_ratings_translations_fix, profile_api_improvements, ratings_minor_fixes, remote_user_fix, send_email_to_admins, stable-spb-1.3, stable-spb-1.3-fixes, stable-spb-1.4, stable-spb-1.5, suggest_rejected_value, web_steps_improvements, xss_terminate_custom_options

Fields verification filters malformed html correctly 

* The field verification now occurs before de validation.
	* Fields that uses the full filter escape residual '<' and '>' after
	  filtering wellformed tags.
	* Fields that uses white_list filter only escape the '<' and '>'
	  symbols if the tag is not wellformed.
	* This patch only fixes the fields that were before being
	  filtered. A full field verification is need to check the way each
	  field must be filtered.

(ActionItem1491)
Showing 26 changed files with 273 additions and 33 deletions   Show diff stats
app/models/article.rb
  Diff comments   View file @688faae
... ... @@ -26,7 +26,7 @@ class Article &lt; ActiveRecord::Base
26 26 article.published_at = article.created_at if article.published_at.nil?
27 27 end
28 28  
29   - xss_terminate :only => [ :name ]
  29 + xss_terminate :only => [ :name ], :on => 'validation'
30 30  
31 31 named_scope :in_category, lambda { |category|
32 32 {:include => 'categories', :conditions => { 'categories.id' => category.id }}
... ...
app/models/comment.rb
  Diff comments   View file @688faae
... ... @@ -17,7 +17,7 @@ class Comment &lt; ActiveRecord::Base
17 17 end
18 18 end
19 19  
20   - xss_terminate :only => [ :body, :title, :name ]
  20 + xss_terminate :only => [ :body, :title, :name ], :on => 'validation'
21 21  
22 22 def author_name
23 23 if author
... ...
app/models/community.rb
  Diff comments   View file @688faae
... ... @@ -5,8 +5,6 @@ class Community &lt; Organization
5 5 settings_items :language
6 6 settings_items :zip_code, :city, :state, :country
7 7  
8   - xss_terminate :only => [ :name, :address, :contact_phone, :description ]
9   -
10 8 before_create do |community|
11 9 community.moderated_articles = true if community.environment.enabled?('organizations_are_moderated_by_default')
12 10 end
... ... @@ -22,6 +20,8 @@ class Community &lt; Organization
22 20 community
23 21 end
24 22  
  23 + xss_terminate :only => [ :name, :address, :contact_phone, :description ], :on => 'validation'
  24 +
25 25 FIELDS = %w[
26 26 city
27 27 state
... ...
app/models/consumption.rb
  Diff comments   View file @688faae
... ... @@ -4,6 +4,6 @@ class Consumption &lt; ActiveRecord::Base
4 4  
5 5 validates_uniqueness_of :product_category_id, :scope => :profile_id
6 6  
7   - xss_terminate :only => [ :aditional_specifications ]
  7 + xss_terminate :only => [ :aditional_specifications ], :on => 'validation'
8 8  
9 9 end
... ...
app/models/environment.rb
  Diff comments   View file @688faae
... ... @@ -471,7 +471,7 @@ class Environment &lt; ActiveRecord::Base
471 471  
472 472 validates_format_of :contact_email, :with => Noosfero::Constants::EMAIL_FORMAT, :if => (lambda { |record| ! record.contact_email.blank? })
473 473  
474   - xss_terminate :only => [ :message_for_disabled_enterprise ], :with => 'white_list'
  474 + xss_terminate :only => [ :message_for_disabled_enterprise ], :with => 'white_list', :on => 'validation'
475 475  
476 476  
477 477 # #################################################
... ...
app/models/event.rb
  Diff comments   View file @688faae
... ... @@ -6,7 +6,8 @@ class Event &lt; Article
6 6 settings_items :link, :type => :string
7 7 settings_items :address, :type => :string
8 8  
9   - xss_terminate :only => [ :description, :link, :address ], :with => 'white_list'
  9 + xss_terminate :only => [ :link ], :on => 'validation'
  10 + xss_terminate :only => [ :description, :link, :address ], :with => 'white_list', :on => 'validation'
10 11  
11 12 validates_presence_of :title, :start_date
12 13  
... ...
app/models/folder.rb
  Diff comments   View file @688faae
... ... @@ -4,7 +4,7 @@ class Folder &lt; Article
4 4  
5 5 settings_items :view_as, :type => :string, :default => 'folder'
6 6  
7   - xss_terminate :only => [ :body ], :with => 'white_list'
  7 + xss_terminate :only => [ :body ], :with => 'white_list', :on => 'validation'
8 8  
9 9 def self.select_views
10 10 [[_('Folder'), 'folder'], [_('Image gallery'), 'image_gallery']]
... ...
app/models/organization.rb
  Diff comments   View file @688faae
... ... @@ -77,7 +77,7 @@ class Organization &lt; Profile
77 77  
78 78 validates_format_of :contact_email, :with => Noosfero::Constants::EMAIL_FORMAT, :if => (lambda { |org| !org.contact_email.blank? })
79 79  
80   - xss_terminate :only => [ :acronym, :contact_person, :contact_email, :legal_form, :economic_activity, :management_information ]
  80 + xss_terminate :only => [ :acronym, :contact_person, :contact_email, :legal_form, :economic_activity, :management_information ], :on => 'validation'
81 81  
82 82 # Yes, organizations have members.
83 83 #
... ...
app/models/product.rb
  Diff comments   View file @688faae
... ... @@ -31,7 +31,7 @@ class Product &lt; ActiveRecord::Base
31 31  
32 32 acts_as_searchable :fields => [ :name, :description, :category_full_name ]
33 33  
34   - xss_terminate :only => [ :name, :description ]
  34 + xss_terminate :only => [ :name, :description ], :on => 'validation'
35 35  
36 36 acts_as_mappable
37 37  
... ...
app/models/profile.rb
  Diff comments   View file @688faae
... ... @@ -294,8 +294,8 @@ class Profile &lt; ActiveRecord::Base
294 294 self.save_without_validation!
295 295 end
296 296  
297   - xss_terminate :only => [ :name, :nickname, :address, :contact_phone, :description ]
298   - xss_terminate :only => [ :custom_footer, :custom_header ], :with => 'white_list'
  297 + xss_terminate :only => [ :name, :nickname, :address, :contact_phone, :description ], :on => 'validation'
  298 + xss_terminate :only => [ :custom_footer, :custom_header ], :with => 'white_list', :on => 'validation'
299 299  
300 300 # returns the contact email for this profile.
301 301 #
... ...
app/models/text_article.rb
  Diff comments   View file @688faae
1 1 # a base class for all text article types.
2 2 class TextArticle < Article
3 3  
4   - xss_terminate :only => [ :name, :abstract, :body ]
  4 + xss_terminate :only => [ :name, :abstract, :body ], :on => 'validation'
5 5 end
... ...
app/models/tiny_mce_article.rb
  Diff comments   View file @688faae
... ... @@ -9,6 +9,6 @@ class TinyMceArticle &lt; TextArticle
9 9 end
10 10  
11 11 xss_terminate :except => [ :abstract, :body ]
12   - xss_terminate :only => [ :abstract, :body ], :with => 'white_list'
  12 + xss_terminate :only => [ :abstract, :body ], :with => 'white_list', :on => 'validation'
13 13  
14 14 end
... ...
app/models/validation_info.rb
  Diff comments   View file @688faae
... ... @@ -3,5 +3,5 @@ class ValidationInfo &lt; ActiveRecord::Base
3 3  
4 4 belongs_to :organization
5 5  
6   - xss_terminate :only => [ :validation_methodology, :restrictions ]
  6 + xss_terminate :only => [ :validation_methodology, :restrictions ], :on => 'validation'
7 7 end
... ...
test/unit/article_test.rb
  Diff comments   View file @688faae
... ... @@ -859,4 +859,20 @@ class ArticleTest &lt; Test::Unit::TestCase
859 859 assert_no_match /</, article.tags.last.name
860 860 end
861 861  
  862 + should 'sanitize name before validation' do
  863 + article = Article.new
  864 + article.name = "<h1 Bla </h1>"
  865 + article.valid?
  866 +
  867 + assert article.errors.invalid?(:name)
  868 + end
  869 +
  870 + should 'escape malformed html tags' do
  871 + article = Article.new
  872 + article.name = "<h1 Malformed >> html >< tag"
  873 + article.valid?
  874 +
  875 + assert_no_match /[<>]/, article.name
  876 + end
  877 +
862 878 end
... ...
test/unit/comment_test.rb
  Diff comments   View file @688faae
... ... @@ -187,4 +187,26 @@ class CommentTest &lt; Test::Unit::TestCase
187 187 assert_no_match(/<script>/, comment.name)
188 188 end
189 189  
  190 + should 'sanitize required fields before validation' do
  191 + owner = create_user('testuser').person
  192 + article = owner.articles.create(:name => 'test', :body => '...')
  193 + comment = article.comments.new(:title => '<h1 title </h1>', :body => '<h1 body </h1>', :name => '<h1 name </h1>', :email => 'cracker@test.org')
  194 + comment.valid?
  195 +
  196 + assert comment.errors.invalid?(:name)
  197 + assert comment.errors.invalid?(:title)
  198 + assert comment.errors.invalid?(:body)
  199 + end
  200 +
  201 + should 'escape malformed html tags' do
  202 + owner = create_user('testuser').person
  203 + article = owner.articles.create(:name => 'test', :body => '...')
  204 + comment = article.comments.new(:title => '<h1 title </h1>>> sd f <<', :body => '<h1>> sdf><asd>< body </h1>', :name => '<h1 name </h1>>><<dfsf<sd', :email => 'cracker@test.org')
  205 + comment.valid?
  206 +
  207 + assert_no_match /[<>]/, comment.title
  208 + assert_no_match /[<>]/, comment.body
  209 + assert_no_match /[<>]/, comment.name
  210 + end
  211 +
190 212 end
... ...
test/unit/community_test.rb
  Diff comments   View file @688faae
... ... @@ -114,7 +114,7 @@ class CommunityTest &lt; Test::Unit::TestCase
114 114 should 'require fields if community needs' do
115 115 e = Environment.default
116 116 e.expects(:required_community_fields).returns(['contact_phone']).at_least_once
117   - community = Community.new(:environment => e)
  117 + community = Community.new(:name => 'My community', :environment => e)
118 118 assert ! community.valid?
119 119 assert community.errors.invalid?(:contact_phone)
120 120  
... ... @@ -200,4 +200,19 @@ class CommunityTest &lt; Test::Unit::TestCase
200 200 community.add_member(person)
201 201 end
202 202 end
  203 +
  204 + should 'escape malformed html tags' do
  205 + community = Community.new
  206 + community.name = "<h1 Malformed >> html >< tag"
  207 + community.address = "<h1 Malformed >,<<<asfdf> html >< tag"
  208 + community.contact_phone = "<h1 Malformed<<> >> html >><>< tag"
  209 + community.description = "<h1 Malformed /h1>>><<> html ><>h1< tag"
  210 + community.valid?
  211 +
  212 + assert_no_match /[<>]/, community.name
  213 + assert_no_match /[<>]/, community.address
  214 + assert_no_match /[<>]/, community.contact_phone
  215 + assert_no_match /[<>]/, community.description
  216 + end
  217 +
203 218 end
... ...
test/unit/consumption_test.rb
  Diff comments   View file @688faae
... ... @@ -3,8 +3,12 @@ require File.dirname(__FILE__) + &#39;/../test_helper&#39;
3 3 class ConsumptionTest < Test::Unit::TestCase
4 4 fixtures :consumptions
5 5  
6   - # Replace this with your real tests.
7   - def test_truth
8   - assert true
  6 + should 'escape malformed html tags' do
  7 + consumption = Consumption.new
  8 + consumption.aditional_specifications = "<h1 Malformed >> html >< tag"
  9 + consumption.valid?
  10 +
  11 + assert_no_match /[<>]/, consumption.aditional_specifications
9 12 end
  13 +
10 14 end
... ...
test/unit/environment_test.rb
  Diff comments   View file @688faae
... ... @@ -863,4 +863,20 @@ class EnvironmentTest &lt; Test::Unit::TestCase
863 863 assert_equal env.message_for_member_invitation, env.invitation_mail_template(community)
864 864 end
865 865  
  866 + should 'filter fields with white_list filter' do
  867 + environment = Environment.new
  868 + environment.message_for_disabled_enterprise = "<h1> Disabled Enterprise </h1>"
  869 + environment.valid?
  870 +
  871 + assert_equal "<h1> Disabled Enterprise </h1>", environment.message_for_disabled_enterprise
  872 + end
  873 +
  874 + should 'escape malformed html tags' do
  875 + environment = Environment.new
  876 + environment.message_for_disabled_enterprise = "<h1> Disabled Enterprise /h1>"
  877 + environment.valid?
  878 +
  879 + assert_no_match /[<>]/, environment.message_for_disabled_enterprise
  880 + end
  881 +
866 882 end
... ...
test/unit/event_test.rb
  Diff comments   View file @688faae
... ... @@ -222,4 +222,32 @@ class EventTest &lt; ActiveSupport::TestCase
222 222 assert_not_includes profile.events.by_day(today), event_out_of_range
223 223 end
224 224  
  225 + should 'filter fields with full filter' do
  226 + event = Event.new
  227 + event.link = "<h1 Malformed >> html >< tag"
  228 + event.valid?
  229 +
  230 + assert_no_match /[<>]/, event.link
  231 + end
  232 +
  233 + should 'filter fields with white_list filter' do
  234 + event = Event.new
  235 + event.description = "<h1> Description </h1>"
  236 + event.address = "<strong> Address <strong>"
  237 + event.valid?
  238 +
  239 + assert_equal "<h1> Description </h1>", event.description
  240 + assert_equal "<strong> Address <strong>", event.address
  241 + end
  242 +
  243 + should 'escape malformed html tags' do
  244 + event = Event.new
  245 + event.description = "<h1<< Description >>/h1>"
  246 + event.address = "<strong>><< Address <strong>"
  247 + event.valid?
  248 +
  249 + assert_no_match /[<>]/, event.description
  250 + assert_no_match /[<>]/, event.address
  251 + end
  252 +
225 253 end
... ...
test/unit/folder_test.rb
  Diff comments   View file @688faae
... ... @@ -125,17 +125,27 @@ class FolderTest &lt; ActiveSupport::TestCase
125 125 end
126 126  
127 127 should 'not let pass javascript in the body' do
128   - owner = create_user('testuser').person
129   - folder = fast_create(Folder, {:profile_id => owner.id, :body => '<script>alert("Xss Attack!")</script>'})
130   - folder.save!
131   - assert_no_match(/<script>/, folder.body)
  128 + folder = Folder.new
  129 + folder.body = "<script> alert(Xss!); </script>"
  130 + folder.valid?
  131 +
  132 + assert_no_match /(<script>)/, folder.body
132 133 end
133 134  
134   - should 'let pass html in the body' do
135   - owner = create_user('testuser').person
136   - folder = fast_create(Folder, {:profile_id => owner.id, :body => '<strong>I am not a Xss Attack!")</strong>'})
137   - folder.save!
138   - assert_match(/<strong>/, folder.body)
  135 + should 'filter fields with white_list filter' do
  136 + folder = Folder.new
  137 + folder.body = "<h1> Body </h1>"
  138 + folder.valid?
  139 +
  140 + assert_equal "<h1> Body </h1>", folder.body
  141 + end
  142 +
  143 + should 'escape malformed html tags' do
  144 + folder = Folder.new
  145 + folder.body = "<h1<< Description >>/h1>"
  146 + folder.valid?
  147 +
  148 + assert_no_match /[<>]/, folder.body
139 149 end
140 150  
141 151 end
... ...
test/unit/organization_test.rb
  Diff comments   View file @688faae
... ... @@ -248,4 +248,24 @@ class OrganizationTest &lt; Test::Unit::TestCase
248 248  
249 249 assert organization.closed
250 250 end
  251 +
  252 + should 'escape malformed html tags' do
  253 + organization = Organization.new
  254 + organization.acronym = "<h1 Malformed >> html >< tag"
  255 + organization.contact_person = "<h1 Malformed >,<<<asfdf> html >< tag"
  256 + organization.contact_email = "<h1<malformed@html.com>>"
  257 + organization.description = "<h1 Malformed /h1>>><<> html ><>h1< tag"
  258 + organization.legal_form = "<h1 Malformed /h1>>><<> html ><>h1< tag"
  259 + organization.economic_activity = "<h1 Malformed /h1>>><<> html ><>h1< tag"
  260 + organization.management_information = "<h1 Malformed /h1>>><<> html ><>h1< tag"
  261 + organization.valid?
  262 +
  263 + assert_no_match /[<>]/, organization.acronym
  264 + assert_no_match /[<>]/, organization.contact_person
  265 + assert_no_match /[<>]/, organization.contact_email
  266 + assert_no_match /[<>]/, organization.legal_form
  267 + assert_no_match /[<>]/, organization.economic_activity
  268 + assert_no_match /[<>]/, organization.management_information
  269 + end
  270 +
251 271 end
... ...
test/unit/product_test.rb
  Diff comments   View file @688faae
... ... @@ -193,4 +193,22 @@ class ProductTest &lt; Test::Unit::TestCase
193 193 end
194 194 end
195 195  
  196 + should 'sanitize name before validation' do
  197 + product = Product.new
  198 + product.name = "<h1 Bla </h1>"
  199 + product.valid?
  200 +
  201 + assert product.errors.invalid?(:name)
  202 + end
  203 +
  204 + should 'escape malformed html tags' do
  205 + product = Product.new
  206 + product.name = "<h1 Malformed >> html >< tag"
  207 + product.description = "<h1 Malformed</h1>><<<a>> >> html >< tag"
  208 + product.valid?
  209 +
  210 + assert_no_match /[<>]/, product.name
  211 + assert_no_match /[<>]/, product.description
  212 + end
  213 +
196 214 end
... ...
test/unit/profile_test.rb
  Diff comments   View file @688faae
... ... @@ -1515,6 +1515,44 @@ class ProfileTest &lt; Test::Unit::TestCase
1515 1515 assert profile.errors.invalid?(:description)
1516 1516 end
1517 1517  
  1518 + should 'sanitize name before validation' do
  1519 + profile = Profile.new
  1520 + profile.name = "<h1 Bla </h1>"
  1521 + profile.valid?
  1522 +
  1523 + assert profile.errors.invalid?(:name)
  1524 + end
  1525 +
  1526 + should 'filter fields with white_list filter' do
  1527 + profile = Profile.new
  1528 + profile.custom_header = "<h1> Custom Header </h1>"
  1529 + profile.custom_footer = "<strong> Custom Footer <strong>"
  1530 + profile.valid?
  1531 +
  1532 + assert_equal "<h1> Custom Header </h1>", profile.custom_header
  1533 + assert_equal "<strong> Custom Footer <strong>", profile.custom_footer
  1534 + end
  1535 +
  1536 + should 'escape malformed html tags' do
  1537 + profile = Profile.new
  1538 + profile.name = "<h1 Malformed >> html >>></a>< tag"
  1539 + profile.nickname = "<h1 Malformed <<h1>>< html >< tag"
  1540 + profile.address = "<h1><</h2< Malformed >> html >< tag"
  1541 + profile.contact_phone = "<h1<< Malformed ><>>> html >< tag"
  1542 + profile.description = "<h1<a> Malformed >> html ></a>< tag"
  1543 + profile.custom_header = "<h1<a>><<> Malformed >> html ></a>< tag"
  1544 + profile.custom_footer = "<h1> Malformed <><< html ></a>< tag"
  1545 + profile.valid?
  1546 +
  1547 + assert_no_match /[<>]/, profile.name
  1548 + assert_no_match /[<>]/, profile.nickname
  1549 + assert_no_match /[<>]/, profile.address
  1550 + assert_no_match /[<>]/, profile.contact_phone
  1551 + assert_no_match /[<>]/, profile.description
  1552 + assert_no_match /[<>]/, profile.custom_header
  1553 + assert_no_match /[<>]/, profile.custom_footer
  1554 + end
  1555 +
1518 1556 private
1519 1557  
1520 1558 def assert_invalid_identifier(id)
... ...
test/unit/text_article_test.rb
  Diff comments   View file @688faae
... ... @@ -26,4 +26,17 @@ class TextArticleTest &lt; Test::Unit::TestCase
26 26 assert_equal "the article ...", article.body
27 27 end
28 28  
  29 + should 'escape malformed html tags' do
  30 + person = create_user('testuser').person
  31 + article = TextArticle.new(:profile => person)
  32 + article.name = "<h1 Malformed >> html >>></a>< tag"
  33 + article.abstract = "<h1 Malformed <<h1>>< html >< tag"
  34 + article.body = "<h1><</h2< Malformed >> html >< tag"
  35 + article.valid?
  36 +
  37 + assert_no_match /[<>]/, article.name
  38 + assert_no_match /[<>]/, article.abstract
  39 + assert_no_match /[<>]/, article.body
  40 + end
  41 +
29 42 end
... ...
test/unit/validation_info_test.rb
  Diff comments   View file @688faae
... ... @@ -21,4 +21,14 @@ class ValidationInfoTest &lt; Test::Unit::TestCase
21 21 end
22 22 end
23 23  
  24 + should 'escape malformed html tags' do
  25 + info = ValidationInfo.new
  26 + info.validation_methodology = "<h1 Malformed >> html >< tag"
  27 + info.restrictions = "<h1 Malformed >> html >< tag"
  28 + info.valid?
  29 +
  30 + assert_no_match /[<>]/, info.validation_methodology
  31 + assert_no_match /[<>]/, info.restrictions
  32 + end
  33 +
24 34 end
... ...
vendor/plugins/xss_terminate/lib/xss_terminate.rb
  Diff comments   View file @688faae
... ... @@ -38,7 +38,7 @@ module XssTerminate
38 38  
39 39 module InstanceMethods
40 40  
41   - def sanitize_field(sanitizer, field, serialized = false)
  41 + def sanitize_field(sanitizer, field, serialized = false, with= :full)
42 42 field = field.to_sym
43 43 if serialized
44 44 puts field
... ... @@ -49,8 +49,22 @@ module XssTerminate
49 49 else
50 50 if self[field]
51 51 self[field] = sanitizer.sanitize(self[field])
  52 +
  53 + if with == :full
  54 + self[field] = CGI.escapeHTML(self[field])
  55 + elsif with == :white_list
  56 + self[field] = CGI.escapeHTML(self[field]) if !wellformed_html_tag?(self[field])
  57 + end
  58 +
52 59 else
53 60 self.send("#{field}=", sanitizer.sanitize(self.send("#{field}")))
  61 +
  62 + if with == :full
  63 + self.send("#{field}=", CGI.escapeHTML(self.send("#{field}")))
  64 + elsif with == :white_list
  65 + self.send("#{field}=", CGI.escapeHTML(self.send("#{field}"))) if !wellformed_html_tag?(self.send("#{field}"))
  66 + end
  67 +
54 68 end
55 69 end
56 70 end
... ... @@ -69,7 +83,7 @@ module XssTerminate
69 83 sanitizer = RailsSanitize.full_sanitizer
70 84 columns, columns_serialized = sanitize_columns(:full)
71 85 columns.each do |column|
72   - sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column))
  86 + sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column), :full)
73 87 end
74 88 end
75 89  
... ... @@ -77,18 +91,33 @@ module XssTerminate
77 91 sanitizer = RailsSanitize.white_list_sanitizer
78 92 columns, columns_serialized = sanitize_columns(:white_list)
79 93 columns.each do |column|
80   - sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column))
  94 + sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column), :white_list)
81 95 end
82   - end
  96 + end
83 97  
84 98 def sanitize_fields_with_html5lib
85 99 sanitizer = HTML5libSanitize.new
86 100 columns = sanitize_columns(:html5lib)
87 101 columns.each do |column|
88   - sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column))
  102 + sanitize_field(sanitizer, column.to_sym, columns_serialized.include?(column), :html5lib)
89 103 end
90 104 end
91 105  
  106 + def wellformed_html_tag?(field)
  107 + return true if !field
  108 +
  109 + counter = 0
  110 + field.split(//).each do |letter|
  111 + counter += 1 if letter == '<'
  112 + counter -= 1 if letter == '>'
  113 + if counter < 0 || 1 < counter
  114 + return false
  115 + end
  116 + end
  117 +
  118 + return counter == 0
  119 + end
  120 +
92 121 end
93 122  
94 123 end
... ...