usr/lib/python3.6/site-packages/html5lib/filters/sanitizer.py000064400000061014147205374430020200 0ustar00from __future__ import absolute_import, division, unicode_literals import re from xml.sax.saxutils import escape, unescape from six.moves import urllib_parse as urlparse from . import base from ..constants import namespaces, prefixes __all__ = ["Filter"] allowed_elements = frozenset(( (namespaces['html'], 'a'), (namespaces['html'], 'abbr'), (namespaces['html'], 'acronym'), (namespaces['html'], 'address'), (namespaces['html'], 'area'), (namespaces['html'], 'article'), (namespaces['html'], 'aside'), (namespaces['html'], 'audio'), (namespaces['html'], 'b'), (namespaces['html'], 'big'), (namespaces['html'], 'blockquote'), (namespaces['html'], 'br'), (namespaces['html'], 'button'), (namespaces['html'], 'canvas'), (namespaces['html'], 'caption'), (namespaces['html'], 'center'), (namespaces['html'], 'cite'), (namespaces['html'], 'code'), (namespaces['html'], 'col'), (namespaces['html'], 'colgroup'), (namespaces['html'], 'command'), (namespaces['html'], 'datagrid'), (namespaces['html'], 'datalist'), (namespaces['html'], 'dd'), (namespaces['html'], 'del'), (namespaces['html'], 'details'), (namespaces['html'], 'dfn'), (namespaces['html'], 'dialog'), (namespaces['html'], 'dir'), (namespaces['html'], 'div'), (namespaces['html'], 'dl'), (namespaces['html'], 'dt'), (namespaces['html'], 'em'), (namespaces['html'], 'event-source'), (namespaces['html'], 'fieldset'), (namespaces['html'], 'figcaption'), (namespaces['html'], 'figure'), (namespaces['html'], 'footer'), (namespaces['html'], 'font'), (namespaces['html'], 'form'), (namespaces['html'], 'header'), (namespaces['html'], 'h1'), (namespaces['html'], 'h2'), (namespaces['html'], 'h3'), (namespaces['html'], 'h4'), (namespaces['html'], 'h5'), (namespaces['html'], 'h6'), (namespaces['html'], 'hr'), (namespaces['html'], 'i'), (namespaces['html'], 'img'), (namespaces['html'], 'input'), (namespaces['html'], 'ins'), (namespaces['html'], 'keygen'), (namespaces['html'], 'kbd'), (namespaces['html'], 'label'), (namespaces['html'], 'legend'), (namespaces['html'], 'li'), (namespaces['html'], 'm'), (namespaces['html'], 'map'), (namespaces['html'], 'menu'), (namespaces['html'], 'meter'), (namespaces['html'], 'multicol'), (namespaces['html'], 'nav'), (namespaces['html'], 'nextid'), (namespaces['html'], 'ol'), (namespaces['html'], 'output'), (namespaces['html'], 'optgroup'), (namespaces['html'], 'option'), (namespaces['html'], 'p'), (namespaces['html'], 'pre'), (namespaces['html'], 'progress'), (namespaces['html'], 'q'), (namespaces['html'], 's'), (namespaces['html'], 'samp'), (namespaces['html'], 'section'), (namespaces['html'], 'select'), (namespaces['html'], 'small'), (namespaces['html'], 'sound'), (namespaces['html'], 'source'), (namespaces['html'], 'spacer'), (namespaces['html'], 'span'), (namespaces['html'], 'strike'), (namespaces['html'], 'strong'), (namespaces['html'], 'sub'), (namespaces['html'], 'sup'), (namespaces['html'], 'table'), (namespaces['html'], 'tbody'), (namespaces['html'], 'td'), (namespaces['html'], 'textarea'), (namespaces['html'], 'time'), (namespaces['html'], 'tfoot'), (namespaces['html'], 'th'), (namespaces['html'], 'thead'), (namespaces['html'], 'tr'), (namespaces['html'], 'tt'), (namespaces['html'], 'u'), (namespaces['html'], 'ul'), (namespaces['html'], 'var'), (namespaces['html'], 'video'), (namespaces['mathml'], 'maction'), (namespaces['mathml'], 'math'), (namespaces['mathml'], 'merror'), (namespaces['mathml'], 'mfrac'), (namespaces['mathml'], 'mi'), (namespaces['mathml'], 'mmultiscripts'), (namespaces['mathml'], 'mn'), (namespaces['mathml'], 'mo'), (namespaces['mathml'], 'mover'), (namespaces['mathml'], 'mpadded'), (namespaces['mathml'], 'mphantom'), (namespaces['mathml'], 'mprescripts'), (namespaces['mathml'], 'mroot'), (namespaces['mathml'], 'mrow'), (namespaces['mathml'], 'mspace'), (namespaces['mathml'], 'msqrt'), (namespaces['mathml'], 'mstyle'), (namespaces['mathml'], 'msub'), (namespaces['mathml'], 'msubsup'), (namespaces['mathml'], 'msup'), (namespaces['mathml'], 'mtable'), (namespaces['mathml'], 'mtd'), (namespaces['mathml'], 'mtext'), (namespaces['mathml'], 'mtr'), (namespaces['mathml'], 'munder'), (namespaces['mathml'], 'munderover'), (namespaces['mathml'], 'none'), (namespaces['svg'], 'a'), (namespaces['svg'], 'animate'), (namespaces['svg'], 'animateColor'), (namespaces['svg'], 'animateMotion'), (namespaces['svg'], 'animateTransform'), (namespaces['svg'], 'clipPath'), (namespaces['svg'], 'circle'), (namespaces['svg'], 'defs'), (namespaces['svg'], 'desc'), (namespaces['svg'], 'ellipse'), (namespaces['svg'], 'font-face'), (namespaces['svg'], 'font-face-name'), (namespaces['svg'], 'font-face-src'), (namespaces['svg'], 'g'), (namespaces['svg'], 'glyph'), (namespaces['svg'], 'hkern'), (namespaces['svg'], 'linearGradient'), (namespaces['svg'], 'line'), (namespaces['svg'], 'marker'), (namespaces['svg'], 'metadata'), (namespaces['svg'], 'missing-glyph'), (namespaces['svg'], 'mpath'), (namespaces['svg'], 'path'), (namespaces['svg'], 'polygon'), (namespaces['svg'], 'polyline'), (namespaces['svg'], 'radialGradient'), (namespaces['svg'], 'rect'), (namespaces['svg'], 'set'), (namespaces['svg'], 'stop'), (namespaces['svg'], 'svg'), (namespaces['svg'], 'switch'), (namespaces['svg'], 'text'), (namespaces['svg'], 'title'), (namespaces['svg'], 'tspan'), (namespaces['svg'], 'use'), )) allowed_attributes = frozenset(( # HTML attributes (None, 'abbr'), (None, 'accept'), (None, 'accept-charset'), (None, 'accesskey'), (None, 'action'), (None, 'align'), (None, 'alt'), (None, 'autocomplete'), (None, 'autofocus'), (None, 'axis'), (None, 'background'), (None, 'balance'), (None, 'bgcolor'), (None, 'bgproperties'), (None, 'border'), (None, 'bordercolor'), (None, 'bordercolordark'), (None, 'bordercolorlight'), (None, 'bottompadding'), (None, 'cellpadding'), (None, 'cellspacing'), (None, 'ch'), (None, 'challenge'), (None, 'char'), (None, 'charoff'), (None, 'choff'), (None, 'charset'), (None, 'checked'), (None, 'cite'), (None, 'class'), (None, 'clear'), (None, 'color'), (None, 'cols'), (None, 'colspan'), (None, 'compact'), (None, 'contenteditable'), (None, 'controls'), (None, 'coords'), (None, 'data'), (None, 'datafld'), (None, 'datapagesize'), (None, 'datasrc'), (None, 'datetime'), (None, 'default'), (None, 'delay'), (None, 'dir'), (None, 'disabled'), (None, 'draggable'), (None, 'dynsrc'), (None, 'enctype'), (None, 'end'), (None, 'face'), (None, 'for'), (None, 'form'), (None, 'frame'), (None, 'galleryimg'), (None, 'gutter'), (None, 'headers'), (None, 'height'), (None, 'hidefocus'), (None, 'hidden'), (None, 'high'), (None, 'href'), (None, 'hreflang'), (None, 'hspace'), (None, 'icon'), (None, 'id'), (None, 'inputmode'), (None, 'ismap'), (None, 'keytype'), (None, 'label'), (None, 'leftspacing'), (None, 'lang'), (None, 'list'), (None, 'longdesc'), (None, 'loop'), (None, 'loopcount'), (None, 'loopend'), (None, 'loopstart'), (None, 'low'), (None, 'lowsrc'), (None, 'max'), (None, 'maxlength'), (None, 'media'), (None, 'method'), (None, 'min'), (None, 'multiple'), (None, 'name'), (None, 'nohref'), (None, 'noshade'), (None, 'nowrap'), (None, 'open'), (None, 'optimum'), (None, 'pattern'), (None, 'ping'), (None, 'point-size'), (None, 'poster'), (None, 'pqg'), (None, 'preload'), (None, 'prompt'), (None, 'radiogroup'), (None, 'readonly'), (None, 'rel'), (None, 'repeat-max'), (None, 'repeat-min'), (None, 'replace'), (None, 'required'), (None, 'rev'), (None, 'rightspacing'), (None, 'rows'), (None, 'rowspan'), (None, 'rules'), (None, 'scope'), (None, 'selected'), (None, 'shape'), (None, 'size'), (None, 'span'), (None, 'src'), (None, 'start'), (None, 'step'), (None, 'style'), (None, 'summary'), (None, 'suppress'), (None, 'tabindex'), (None, 'target'), (None, 'template'), (None, 'title'), (None, 'toppadding'), (None, 'type'), (None, 'unselectable'), (None, 'usemap'), (None, 'urn'), (None, 'valign'), (None, 'value'), (None, 'variable'), (None, 'volume'), (None, 'vspace'), (None, 'vrml'), (None, 'width'), (None, 'wrap'), (namespaces['xml'], 'lang'), # MathML attributes (None, 'actiontype'), (None, 'align'), (None, 'columnalign'), (None, 'columnalign'), (None, 'columnalign'), (None, 'columnlines'), (None, 'columnspacing'), (None, 'columnspan'), (None, 'depth'), (None, 'display'), (None, 'displaystyle'), (None, 'equalcolumns'), (None, 'equalrows'), (None, 'fence'), (None, 'fontstyle'), (None, 'fontweight'), (None, 'frame'), (None, 'height'), (None, 'linethickness'), (None, 'lspace'), (None, 'mathbackground'), (None, 'mathcolor'), (None, 'mathvariant'), (None, 'mathvariant'), (None, 'maxsize'), (None, 'minsize'), (None, 'other'), (None, 'rowalign'), (None, 'rowalign'), (None, 'rowalign'), (None, 'rowlines'), (None, 'rowspacing'), (None, 'rowspan'), (None, 'rspace'), (None, 'scriptlevel'), (None, 'selection'), (None, 'separator'), (None, 'stretchy'), (None, 'width'), (None, 'width'), (namespaces['xlink'], 'href'), (namespaces['xlink'], 'show'), (namespaces['xlink'], 'type'), # SVG attributes (None, 'accent-height'), (None, 'accumulate'), (None, 'additive'), (None, 'alphabetic'), (None, 'arabic-form'), (None, 'ascent'), (None, 'attributeName'), (None, 'attributeType'), (None, 'baseProfile'), (None, 'bbox'), (None, 'begin'), (None, 'by'), (None, 'calcMode'), (None, 'cap-height'), (None, 'class'), (None, 'clip-path'), (None, 'color'), (None, 'color-rendering'), (None, 'content'), (None, 'cx'), (None, 'cy'), (None, 'd'), (None, 'dx'), (None, 'dy'), (None, 'descent'), (None, 'display'), (None, 'dur'), (None, 'end'), (None, 'fill'), (None, 'fill-opacity'), (None, 'fill-rule'), (None, 'font-family'), (None, 'font-size'), (None, 'font-stretch'), (None, 'font-style'), (None, 'font-variant'), (None, 'font-weight'), (None, 'from'), (None, 'fx'), (None, 'fy'), (None, 'g1'), (None, 'g2'), (None, 'glyph-name'), (None, 'gradientUnits'), (None, 'hanging'), (None, 'height'), (None, 'horiz-adv-x'), (None, 'horiz-origin-x'), (None, 'id'), (None, 'ideographic'), (None, 'k'), (None, 'keyPoints'), (None, 'keySplines'), (None, 'keyTimes'), (None, 'lang'), (None, 'marker-end'), (None, 'marker-mid'), (None, 'marker-start'), (None, 'markerHeight'), (None, 'markerUnits'), (None, 'markerWidth'), (None, 'mathematical'), (None, 'max'), (None, 'min'), (None, 'name'), (None, 'offset'), (None, 'opacity'), (None, 'orient'), (None, 'origin'), (None, 'overline-position'), (None, 'overline-thickness'), (None, 'panose-1'), (None, 'path'), (None, 'pathLength'), (None, 'points'), (None, 'preserveAspectRatio'), (None, 'r'), (None, 'refX'), (None, 'refY'), (None, 'repeatCount'), (None, 'repeatDur'), (None, 'requiredExtensions'), (None, 'requiredFeatures'), (None, 'restart'), (None, 'rotate'), (None, 'rx'), (None, 'ry'), (None, 'slope'), (None, 'stemh'), (None, 'stemv'), (None, 'stop-color'), (None, 'stop-opacity'), (None, 'strikethrough-position'), (None, 'strikethrough-thickness'), (None, 'stroke'), (None, 'stroke-dasharray'), (None, 'stroke-dashoffset'), (None, 'stroke-linecap'), (None, 'stroke-linejoin'), (None, 'stroke-miterlimit'), (None, 'stroke-opacity'), (None, 'stroke-width'), (None, 'systemLanguage'), (None, 'target'), (None, 'text-anchor'), (None, 'to'), (None, 'transform'), (None, 'type'), (None, 'u1'), (None, 'u2'), (None, 'underline-position'), (None, 'underline-thickness'), (None, 'unicode'), (None, 'unicode-range'), (None, 'units-per-em'), (None, 'values'), (None, 'version'), (None, 'viewBox'), (None, 'visibility'), (None, 'width'), (None, 'widths'), (None, 'x'), (None, 'x-height'), (None, 'x1'), (None, 'x2'), (namespaces['xlink'], 'actuate'), (namespaces['xlink'], 'arcrole'), (namespaces['xlink'], 'href'), (namespaces['xlink'], 'role'), (namespaces['xlink'], 'show'), (namespaces['xlink'], 'title'), (namespaces['xlink'], 'type'), (namespaces['xml'], 'base'), (namespaces['xml'], 'lang'), (namespaces['xml'], 'space'), (None, 'y'), (None, 'y1'), (None, 'y2'), (None, 'zoomAndPan'), )) attr_val_is_uri = frozenset(( (None, 'href'), (None, 'src'), (None, 'cite'), (None, 'action'), (None, 'longdesc'), (None, 'poster'), (None, 'background'), (None, 'datasrc'), (None, 'dynsrc'), (None, 'lowsrc'), (None, 'ping'), (namespaces['xlink'], 'href'), (namespaces['xml'], 'base'), )) svg_attr_val_allows_ref = frozenset(( (None, 'clip-path'), (None, 'color-profile'), (None, 'cursor'), (None, 'fill'), (None, 'filter'), (None, 'marker'), (None, 'marker-start'), (None, 'marker-mid'), (None, 'marker-end'), (None, 'mask'), (None, 'stroke'), )) svg_allow_local_href = frozenset(( (None, 'altGlyph'), (None, 'animate'), (None, 'animateColor'), (None, 'animateMotion'), (None, 'animateTransform'), (None, 'cursor'), (None, 'feImage'), (None, 'filter'), (None, 'linearGradient'), (None, 'pattern'), (None, 'radialGradient'), (None, 'textpath'), (None, 'tref'), (None, 'set'), (None, 'use') )) allowed_css_properties = frozenset(( 'azimuth', 'background-color', 'border-bottom-color', 'border-collapse', 'border-color', 'border-left-color', 'border-right-color', 'border-top-color', 'clear', 'color', 'cursor', 'direction', 'display', 'elevation', 'float', 'font', 'font-family', 'font-size', 'font-style', 'font-variant', 'font-weight', 'height', 'letter-spacing', 'line-height', 'overflow', 'pause', 'pause-after', 'pause-before', 'pitch', 'pitch-range', 'richness', 'speak', 'speak-header', 'speak-numeral', 'speak-punctuation', 'speech-rate', 'stress', 'text-align', 'text-decoration', 'text-indent', 'unicode-bidi', 'vertical-align', 'voice-family', 'volume', 'white-space', 'width', )) allowed_css_keywords = frozenset(( 'auto', 'aqua', 'black', 'block', 'blue', 'bold', 'both', 'bottom', 'brown', 'center', 'collapse', 'dashed', 'dotted', 'fuchsia', 'gray', 'green', '!important', 'italic', 'left', 'lime', 'maroon', 'medium', 'none', 'navy', 'normal', 'nowrap', 'olive', 'pointer', 'purple', 'red', 'right', 'solid', 'silver', 'teal', 'top', 'transparent', 'underline', 'white', 'yellow', )) allowed_svg_properties = frozenset(( 'fill', 'fill-opacity', 'fill-rule', 'stroke', 'stroke-width', 'stroke-linecap', 'stroke-linejoin', 'stroke-opacity', )) allowed_protocols = frozenset(( 'ed2k', 'ftp', 'http', 'https', 'irc', 'mailto', 'news', 'gopher', 'nntp', 'telnet', 'webcal', 'xmpp', 'callto', 'feed', 'urn', 'aim', 'rsync', 'tag', 'ssh', 'sftp', 'rtsp', 'afs', 'data', )) allowed_content_types = frozenset(( 'image/png', 'image/jpeg', 'image/gif', 'image/webp', 'image/bmp', 'text/plain', )) data_content_type = re.compile(r''' ^ # Match a content type / (?P[-a-zA-Z0-9.]+/[-a-zA-Z0-9.]+) # Match any character set and encoding (?:(?:;charset=(?:[-a-zA-Z0-9]+)(?:;(?:base64))?) |(?:;(?:base64))?(?:;charset=(?:[-a-zA-Z0-9]+))?) # Assume the rest is data ,.* $ ''', re.VERBOSE) class Filter(base.Filter): """ sanitization of XHTML+MathML+SVG and of inline style attributes.""" def __init__(self, source, allowed_elements=allowed_elements, allowed_attributes=allowed_attributes, allowed_css_properties=allowed_css_properties, allowed_css_keywords=allowed_css_keywords, allowed_svg_properties=allowed_svg_properties, allowed_protocols=allowed_protocols, allowed_content_types=allowed_content_types, attr_val_is_uri=attr_val_is_uri, svg_attr_val_allows_ref=svg_attr_val_allows_ref, svg_allow_local_href=svg_allow_local_href): super(Filter, self).__init__(source) self.allowed_elements = allowed_elements self.allowed_attributes = allowed_attributes self.allowed_css_properties = allowed_css_properties self.allowed_css_keywords = allowed_css_keywords self.allowed_svg_properties = allowed_svg_properties self.allowed_protocols = allowed_protocols self.allowed_content_types = allowed_content_types self.attr_val_is_uri = attr_val_is_uri self.svg_attr_val_allows_ref = svg_attr_val_allows_ref self.svg_allow_local_href = svg_allow_local_href def __iter__(self): for token in base.Filter.__iter__(self): token = self.sanitize_token(token) if token: yield token # Sanitize the +html+, escaping all elements not in ALLOWED_ELEMENTS, and # stripping out all # attributes not in ALLOWED_ATTRIBUTES. Style # attributes are parsed, and a restricted set, # specified by # ALLOWED_CSS_PROPERTIES and ALLOWED_CSS_KEYWORDS, are allowed through. # attributes in ATTR_VAL_IS_URI are scanned, and only URI schemes specified # in ALLOWED_PROTOCOLS are allowed. # # sanitize_html('') # => <script> do_nasty_stuff() </script> # sanitize_html('Click here for $100') # => Click here for $100 def sanitize_token(self, token): # accommodate filters which use token_type differently token_type = token["type"] if token_type in ("StartTag", "EndTag", "EmptyTag"): name = token["name"] namespace = token["namespace"] if ((namespace, name) in self.allowed_elements or (namespace is None and (namespaces["html"], name) in self.allowed_elements)): return self.allowed_token(token) else: return self.disallowed_token(token) elif token_type == "Comment": pass else: return token def allowed_token(self, token): if "data" in token: attrs = token["data"] attr_names = set(attrs.keys()) # Remove forbidden attributes for to_remove in (attr_names - self.allowed_attributes): del token["data"][to_remove] attr_names.remove(to_remove) # Remove attributes with disallowed URL values for attr in (attr_names & self.attr_val_is_uri): assert attr in attrs # I don't have a clue where this regexp comes from or why it matches those # characters, nor why we call unescape. I just know it's always been here. # Should you be worried by this comment in a sanitizer? Yes. On the other hand, all # this will do is remove *more* than it otherwise would. val_unescaped = re.sub("[`\x00-\x20\x7f-\xa0\s]+", '', unescape(attrs[attr])).lower() # remove replacement characters from unescaped characters val_unescaped = val_unescaped.replace("\ufffd", "") try: uri = urlparse.urlparse(val_unescaped) except ValueError: uri = None del attrs[attr] if uri and uri.scheme: if uri.scheme not in self.allowed_protocols: del attrs[attr] if uri.scheme == 'data': m = data_content_type.match(uri.path) if not m: del attrs[attr] elif m.group('content_type') not in self.allowed_content_types: del attrs[attr] for attr in self.svg_attr_val_allows_ref: if attr in attrs: attrs[attr] = re.sub(r'url\s*\(\s*[^#\s][^)]+?\)', ' ', unescape(attrs[attr])) if (token["name"] in self.svg_allow_local_href and (namespaces['xlink'], 'href') in attrs and re.search('^\s*[^#\s].*', attrs[(namespaces['xlink'], 'href')])): del attrs[(namespaces['xlink'], 'href')] if (None, 'style') in attrs: attrs[(None, 'style')] = self.sanitize_css(attrs[(None, 'style')]) token["data"] = attrs return token def disallowed_token(self, token): token_type = token["type"] if token_type == "EndTag": token["data"] = "" % token["name"] elif token["data"]: assert token_type in ("StartTag", "EmptyTag") attrs = [] for (ns, name), v in token["data"].items(): attrs.append(' %s="%s"' % (name if ns is None else "%s:%s" % (prefixes[ns], name), escape(v))) token["data"] = "<%s%s>" % (token["name"], ''.join(attrs)) else: token["data"] = "<%s>" % token["name"] if token.get("selfClosing"): token["data"] = token["data"][:-1] + "/>" token["type"] = "Characters" del token["name"] return token def sanitize_css(self, style): # disallow urls style = re.compile('url\s*\(\s*[^\s)]+?\s*\)\s*').sub(' ', style) # gauntlet if not re.match("""^([:,;#%.\sa-zA-Z0-9!]|\w-\w|'[\s\w]+'|"[\s\w]+"|\([\d,\s]+\))*$""", style): return '' if not re.match("^\s*([-\w]+\s*:[^:;]*(;\s*|$))*$", style): return '' clean = [] for prop, value in re.findall("([-\w]+)\s*:\s*([^:;]*)", style): if not value: continue if prop.lower() in self.allowed_css_properties: clean.append(prop + ': ' + value + ';') elif prop.split('-')[0].lower() in ['background', 'border', 'margin', 'padding']: for keyword in value.split(): if keyword not in self.allowed_css_keywords and \ not re.match("^(#[0-9a-f]+|rgb\(\d+%?,\d*%?,?\d*%?\)?|\d{0,2}\.?\d{0,2}(cm|em|ex|in|mm|pc|pt|px|%|,|\))?)$", keyword): # noqa break else: clean.append(prop + ': ' + value + ';') elif prop.lower() in self.allowed_svg_properties: clean.append(prop + ': ' + value + ';') return ' '.join(clean)