AMP_Blacklist_Sanitizer::validate_a_node() - Code Metrics - Inspection of "Initial proof of concept for AMP Integration" - Automattic/jetpack - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — add/amp-pwa-experiment ( efea12 )

unknown

created 2017-06-15 19:11 UTC

AMP_Blacklist_Sanitizer::validate_a_node() C

↳ Parent: AMP_Blacklist_Sanitizer

Complexity

Conditions	8
Paths	9

Size

Total Lines	40
Code Lines	21

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	8
eloc	21
nc	9
nop	1
dl	0
loc	40
rs	5.3846
c	0
b	0
f	0

<?php

require_once( AMP__ROOT__ . '/includes/sanitizers/class-amp-base-sanitizer.php' );

/**
 * Strips blacklisted tags and attributes from content.
 *
 * See following for blacklist:
 *     https://github.com/ampproject/amphtml/blob/master/spec/amp-html-format.md#html-tags
 */
class AMP_Blacklist_Sanitizer extends AMP_Base_Sanitizer {
	const PATTERN_REL_WP_ATTACHMENT = '#wp-att-([\d]+)#';

	protected $DEFAULT_ARGS = array(
		'add_blacklisted_protocols' => array(),
		'add_blacklisted_tags' => array(),
		'add_blacklisted_attributes' => array(),
	);

	public function sanitize() {
		$blacklisted_tags = $this->get_blacklisted_tags();
		$blacklisted_attributes = $this->get_blacklisted_attributes();
		$blacklisted_protocols = $this->get_blacklisted_protocols();

		$body = $this->get_body_node();
		$this->strip_tags( $body, $blacklisted_tags );
		$this->strip_attributes_recursive( $body, $blacklisted_attributes, $blacklisted_protocols );
	}

	private function strip_attributes_recursive( $node, $bad_attributes, $bad_protocols ) {
		if ( $node->nodeType !== XML_ELEMENT_NODE ) {
			return;
		}

		$node_name = $node->nodeName;

		// Some nodes may contain valid content but are themselves invalid.
		// Remove the node but preserve the children.
 		if ( 'font' === $node_name ) {
			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
			return;
		} elseif ( 'a' === $node_name && false === $this->validate_a_node( $node ) ) {
			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
			return;
		}

		if ( $node->hasAttributes() ) {
			$length = $node->attributes->length;
			for ( $i = $length - 1; $i >= 0; $i-- ) {
				$attribute = $node->attributes->item( $i );
				$attribute_name = strtolower( $attribute->name );
				if ( in_array( $attribute_name, $bad_attributes ) ) {
					$node->removeAttribute( $attribute_name );
					continue;
				}

				// on* attributes (like onclick) are a special case
				if ( 0 === stripos( $attribute_name, 'on' ) && $attribute_name != 'on' ) {
					$node->removeAttribute( $attribute_name );
					continue;
				} elseif ( 'a' === $node_name ) {
					$this->sanitize_a_attribute( $node, $attribute );
				}
			}
		}

		$length = $node->childNodes->length;
		for ( $i = $length - 1; $i >= 0; $i-- ) {
			$child_node = $node->childNodes->item( $i );

			$this->strip_attributes_recursive( $child_node, $bad_attributes, $bad_protocols );
		}
	}

	private function strip_tags( $node, $tag_names ) {
		foreach ( $tag_names as $tag_name ) {
			$elements = $node->getElementsByTagName( $tag_name );
			$length = $elements->length;
			if ( 0 === $length ) {
				continue;
			}

			for ( $i = $length - 1; $i >= 0; $i-- ) {
				$element = $elements->item( $i );
				$parent_node = $element->parentNode;
				$parent_node->removeChild( $element );

				if ( 'body' !== $parent_node->nodeName && AMP_DOM_Utils::is_node_empty( $parent_node ) ) {
					$parent_node->parentNode->removeChild( $parent_node );
				}
			}
		}
	}

	private function sanitize_a_attribute( $node, $attribute ) {
		$attribute_name = strtolower( $attribute->name );

		if ( 'rel' === $attribute_name ) {
			$old_value = $attribute->value;
			$new_value = trim( preg_replace( self::PATTERN_REL_WP_ATTACHMENT, '', $old_value ) );
			if ( empty( $new_value ) ) {
				$node->removeAttribute( $attribute_name );
			} elseif ( $old_value !== $new_value ) {
				$node->setAttribute( $attribute_name, $new_value );
			}
		} elseif ( 'rev' === $attribute_name ) {
			// rev removed from HTML5 spec, which was used by Jetpack Markdown.
			$node->removeAttribute( $attribute_name );
		} elseif ( 'target' === $attribute_name ) {
			// _blank is the only allowed value and it must be lowercase.
			// replace _new with _blank and others should simply be removed.
			$old_value = strtolower( $attribute->value );
			if ( '_blank' === $old_value || '_new' === $old_value ) {
				// _new is not allowed; swap with _blank
				$node->setAttribute( $attribute_name, '_blank' );
			} else {
				// only _blank is allowed
				$node->removeAttribute( $attribute_name );
			}
		}
	}

	private function validate_a_node( $node ) {
		// Get the href attribute
		$href = $node->getAttribute( 'href' );

		// If no href is set and this isn't an anchor, it's invalid
		if ( empty( $href ) ) {
			$name_attr = $node->getAttribute( 'name' );
			if ( ! empty( $name_attr ) ) {
				// No further validation is required
				return true;
			} else {
				return false;
			}
		}

		// If this is an anchor link, just return true
		if ( 0 === strpos( $href, '#' ) ) {
			return true;
		}

		// If the href starts with a '/', append the home_url to it for validation purposes.
		if ( 0 === stripos( $href, '/' ) ) {
			$href = untrailingslashit( get_home_url() ) . $href;
		}

		$valid_protocols = array( 'http', 'https', 'mailto', 'sms', 'tel', 'viber', 'whatsapp' );
		$special_protocols = array( 'tel', 'sms' ); // these ones don't valid with `filter_var+FILTER_VALIDATE_URL`
		$protocol = strtok( $href, ':' );

		if ( false === filter_var( $href, FILTER_VALIDATE_URL )
			&& ! in_array( $protocol, $special_protocols ) ) {
			return false;
		}

		if ( ! in_array( $protocol, $valid_protocols ) ) {
			return false;
		}

		return true;
	}

	private function replace_node_with_children( $node, $bad_attributes, $bad_protocols ) {
		// If the node has children and also has a parent node,
		// clone and re-add all the children just before current node.
		if ( $node->hasChildNodes() && $node->parentNode ) {
			foreach ( $node->childNodes as $child_node ) {
				$new_child = $child_node->cloneNode( true );
				$this->strip_attributes_recursive( $new_child, $bad_attributes, $bad_protocols );
				$node->parentNode->insertBefore( $new_child, $node );
			}
		}

		// Remove the node from the parent, if defined.
		if ( $node->parentNode ) {
			$node->parentNode->removeChild( $node );
		}
	}

	private function merge_defaults_with_args( $key, $values ) {
		// Merge default values with user specified args
		if ( ! empty( $this->args[ $key ] )
			&& is_array( $this->args[ $key ] ) ) {
			$values = array_merge( $values, $this->args[ $key ] );
		}

		return $values;
	}

	private function get_blacklisted_protocols() {
		return $this->merge_defaults_with_args( 'add_blacklisted_protocols', array(
			'javascript',
		) );
	}

	private function get_blacklisted_tags() {
		return $this->merge_defaults_with_args( 'add_blacklisted_tags', array(
			'script',
			'noscript',
			'style',
			'frame',
			'frameset',
			'object',
			'param',
			'applet',
			'form',
			'label',
			'input',
			'textarea',
			'select',
			'option',
			'link',
			'picture',

			// Sanitizers run after embed handlers, so if anything wasn't matched, it needs to be removed.
			'embed',
			'embedvideo',

			// Other weird ones
			'comments-count',

			// These are converted into amp-* versions
			//'img',
			//'video',
			//'audio',
			//'iframe',
		) );
	}

	private function get_blacklisted_attributes() {
		return $this->merge_defaults_with_args( 'add_blacklisted_attributes', array(
			'style',
			'size',
			'clear',
			'align',
			'valign',
		) );
	}
}


1			<?php
2
3			require_once( AMP__ROOT__ . '/includes/sanitizers/class-amp-base-sanitizer.php' );
4
5			/**
6			* Strips blacklisted tags and attributes from content.
7			*
8			* See following for blacklist:
9			* https://github.com/ampproject/amphtml/blob/master/spec/amp-html-format.md#html-tags
10			*/
11			class AMP_Blacklist_Sanitizer extends AMP_Base_Sanitizer {
12			const PATTERN_REL_WP_ATTACHMENT = '#wp-att-([\d]+)#';
13
14			protected $DEFAULT_ARGS = array(
15			'add_blacklisted_protocols' => array(),
16			'add_blacklisted_tags' => array(),
17			'add_blacklisted_attributes' => array(),
18			);
19
20			public function sanitize() {
21			$blacklisted_tags = $this->get_blacklisted_tags();
22			$blacklisted_attributes = $this->get_blacklisted_attributes();
23			$blacklisted_protocols = $this->get_blacklisted_protocols();
24
25			$body = $this->get_body_node();
26			$this->strip_tags( $body, $blacklisted_tags );
27			$this->strip_attributes_recursive( $body, $blacklisted_attributes, $blacklisted_protocols );
28			}
29
30			private function strip_attributes_recursive( $node, $bad_attributes, $bad_protocols ) {
31			if ( $node->nodeType !== XML_ELEMENT_NODE ) {
32			return;
33			}
34
35			$node_name = $node->nodeName;
36
37			// Some nodes may contain valid content but are themselves invalid.
38			// Remove the node but preserve the children.
39			if ( 'font' === $node_name ) {
40			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
41			return;
42			} elseif ( 'a' === $node_name && false === $this->validate_a_node( $node ) ) {
43			$this->replace_node_with_children( $node, $bad_attributes, $bad_protocols );
44			return;
45			}
46
47			if ( $node->hasAttributes() ) {
48			$length = $node->attributes->length;
49			for ( $i = $length - 1; $i >= 0; $i-- ) {
50			$attribute = $node->attributes->item( $i );
51			$attribute_name = strtolower( $attribute->name );
52			if ( in_array( $attribute_name, $bad_attributes ) ) {
53			$node->removeAttribute( $attribute_name );
54			continue;
55			}
56
57			// on* attributes (like onclick) are a special case
58			if ( 0 === stripos( $attribute_name, 'on' ) && $attribute_name != 'on' ) {
59			$node->removeAttribute( $attribute_name );
60			continue;
61			} elseif ( 'a' === $node_name ) {
62			$this->sanitize_a_attribute( $node, $attribute );
63			}
64			}
65			}
66
67			$length = $node->childNodes->length;
68			for ( $i = $length - 1; $i >= 0; $i-- ) {
69			$child_node = $node->childNodes->item( $i );
70
71			$this->strip_attributes_recursive( $child_node, $bad_attributes, $bad_protocols );
72			}
73			}
74
75			private function strip_tags( $node, $tag_names ) {
76			foreach ( $tag_names as $tag_name ) {
77			$elements = $node->getElementsByTagName( $tag_name );
78			$length = $elements->length;
79			if ( 0 === $length ) {
80			continue;
81			}
82
83			for ( $i = $length - 1; $i >= 0; $i-- ) {
84			$element = $elements->item( $i );
85			$parent_node = $element->parentNode;
86			$parent_node->removeChild( $element );
87
88			if ( 'body' !== $parent_node->nodeName && AMP_DOM_Utils::is_node_empty( $parent_node ) ) {
89			$parent_node->parentNode->removeChild( $parent_node );
90			}
91			}
92			}
93			}
94
95			private function sanitize_a_attribute( $node, $attribute ) {
96			$attribute_name = strtolower( $attribute->name );
97
98			if ( 'rel' === $attribute_name ) {
99			$old_value = $attribute->value;
100			$new_value = trim( preg_replace( self::PATTERN_REL_WP_ATTACHMENT, '', $old_value ) );
101			if ( empty( $new_value ) ) {
102			$node->removeAttribute( $attribute_name );
103			} elseif ( $old_value !== $new_value ) {
104			$node->setAttribute( $attribute_name, $new_value );
105			}
106			} elseif ( 'rev' === $attribute_name ) {
107			// rev removed from HTML5 spec, which was used by Jetpack Markdown.
108			$node->removeAttribute( $attribute_name );
109			} elseif ( 'target' === $attribute_name ) {
110			// _blank is the only allowed value and it must be lowercase.
111			// replace _new with _blank and others should simply be removed.
112			$old_value = strtolower( $attribute->value );
113			if ( '_blank' === $old_value \|\| '_new' === $old_value ) {
114			// _new is not allowed; swap with _blank
115			$node->setAttribute( $attribute_name, '_blank' );
116			} else {
117			// only _blank is allowed
118			$node->removeAttribute( $attribute_name );
119			}
120			}
121			}
122
123			private function validate_a_node( $node ) {
124			// Get the href attribute
125			$href = $node->getAttribute( 'href' );
126
127			// If no href is set and this isn't an anchor, it's invalid
128			if ( empty( $href ) ) {
129			$name_attr = $node->getAttribute( 'name' );
130			if ( ! empty( $name_attr ) ) {
131			// No further validation is required
132			return true;
133			} else {
134			return false;
135			}
136			}
137
138			// If this is an anchor link, just return true
139			if ( 0 === strpos( $href, '#' ) ) {
140			return true;
141			}
142
143			// If the href starts with a '/', append the home_url to it for validation purposes.
144			if ( 0 === stripos( $href, '/' ) ) {
145			$href = untrailingslashit( get_home_url() ) . $href;
146			}
147
148			$valid_protocols = array( 'http', 'https', 'mailto', 'sms', 'tel', 'viber', 'whatsapp' );
149			$special_protocols = array( 'tel', 'sms' ); // these ones don't valid with `filter_var+FILTER_VALIDATE_URL`
150			$protocol = strtok( $href, ':' );
151
152			if ( false === filter_var( $href, FILTER_VALIDATE_URL )
153			&& ! in_array( $protocol, $special_protocols ) ) {
154			return false;
155			}
156
157			if ( ! in_array( $protocol, $valid_protocols ) ) {
158			return false;
159			}
160
161			return true;
162			}
163
164			private function replace_node_with_children( $node, $bad_attributes, $bad_protocols ) {
165			// If the node has children and also has a parent node,
166			// clone and re-add all the children just before current node.
167			if ( $node->hasChildNodes() && $node->parentNode ) {
168			foreach ( $node->childNodes as $child_node ) {
169			$new_child = $child_node->cloneNode( true );
170			$this->strip_attributes_recursive( $new_child, $bad_attributes, $bad_protocols );
171			$node->parentNode->insertBefore( $new_child, $node );
172			}
173			}
174
175			// Remove the node from the parent, if defined.
176			if ( $node->parentNode ) {
177			$node->parentNode->removeChild( $node );
178			}
179			}
180
181			private function merge_defaults_with_args( $key, $values ) {
182			// Merge default values with user specified args
183			if ( ! empty( $this->args[ $key ] )
184			&& is_array( $this->args[ $key ] ) ) {
185			$values = array_merge( $values, $this->args[ $key ] );
186			}
187
188			return $values;
189			}
190
191			private function get_blacklisted_protocols() {
192			return $this->merge_defaults_with_args( 'add_blacklisted_protocols', array(
193			'javascript',
194			) );
195			}
196
197			private function get_blacklisted_tags() {
198			return $this->merge_defaults_with_args( 'add_blacklisted_tags', array(
199			'script',
200			'noscript',
201			'style',
202			'frame',
203			'frameset',
204			'object',
205			'param',
206			'applet',
207			'form',
208			'label',
209			'input',
210			'textarea',
211			'select',
212			'option',
213			'link',
214			'picture',
215
216			// Sanitizers run after embed handlers, so if anything wasn't matched, it needs to be removed.
217			'embed',
218			'embedvideo',
219
220			// Other weird ones
221			'comments-count',
222
223			// These are converted into amp-* versions
224			//'img',
225			//'video',
226			//'audio',
227			//'iframe',
228			) );
229			}
230
231			private function get_blacklisted_attributes() {
232			return $this->merge_defaults_with_args( 'add_blacklisted_attributes', array(
233			'style',
234			'size',
235			'clear',
236			'align',
237			'valign',
238			) );
239			}
240			}
241

Automattic / jetpack

Push — add/amp-pwa-experiment ( efea12 )

AMP_Blacklist_Sanitizer::validate_a_node() C

Complexity

Size

Duplication

Importance

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