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199 lines
6.5 KiB
Python
199 lines
6.5 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Python 富文本XSS过滤类
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@package XssHtml
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@version 0.1
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@link http://phith0n.github.io/python-xss-filter
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@since 20150407
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@copyright (c) Phithon All Rights Reserved
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Based on native Python module HTMLParser purifier of HTML, To Clear all javascript in html
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You can use it in all python web framework
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Written by Phithon <root@leavesongs.com> in 2015 and placed in the public domain.
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phithon <root@leavesongs.com> 编写于20150407
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From: XDSEC <www.xdsec.org> & 离别歌 <www.leavesongs.com>
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GitHub Pages: https://github.com/phith0n/python-xss-filter
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Usage:
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parser = XssHtml()
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parser.feed('<html code>')
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parser.close()
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html = parser.getHtml()
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print html
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Requirements
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Python 2.6+ or 3.2+
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Cannot defense xss in browser which is belowed IE7
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浏览器版本：IE7+ 或其他浏览器，无法防御IE6及以下版本浏览器中的XSS
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"""
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import re
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import copy
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from html.parser import HTMLParser
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class XssHtml(HTMLParser):
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allow_tags = ['a', 'img', 'br', 'strong', 'b', 'code', 'pre',
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'p', 'div', 'em', 'span', 'h1', 'h2', 'h3', 'h4',
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'h5', 'h6', 'blockquote', 'ul', 'ol', 'tr', 'th', 'td',
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'hr', 'li', 'u', 'embed', 's', 'table', 'thead', 'tbody',
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'caption', 'small', 'q', 'sup', 'sub', 'font']
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common_attrs = ["style", "class", "name"]
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nonend_tags = ["img", "hr", "br", "embed"]
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tags_own_attrs = {
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"img": ["src", "width", "height", "alt", "align"],
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"a": ["href", "target", "rel", "title"],
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"embed": ["src", "width", "height", "type", "allowfullscreen", "loop", "play", "wmode", "menu"],
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"table": ["border", "cellpadding", "cellspacing"],
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"font": ["color"]
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}
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def __init__(self, allows=[]):
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HTMLParser.__init__(self)
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self.allow_tags = allows if allows else self.allow_tags
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self.result = []
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self.start = []
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self.data = []
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def getHtml(self):
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"""
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Get the safe html code
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"""
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for i in range(0, len(self.result)):
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if self.result[i].strip('\n'):
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self.data.append(self.result[i])
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return ''.join(self.data)
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def handle_startendtag(self, tag, attrs):
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self.handle_starttag(tag, attrs)
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def handle_starttag(self, tag, attrs):
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if tag not in self.allow_tags:
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return
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end_diagonal = ' /' if tag in self.nonend_tags else ''
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if not end_diagonal:
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self.start.append(tag)
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attdict = {}
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for attr in attrs:
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attdict[attr[0]] = attr[1]
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attdict = self._wash_attr(attdict, tag)
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if hasattr(self, "node_%s" % tag):
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attdict = getattr(self, "node_%s" % tag)(attdict)
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else:
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attdict = self.node_default(attdict)
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attrs = []
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for (key, value) in attdict.items():
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attrs.append('%s="%s"' % (key, self._htmlspecialchars(value)))
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attrs = (' ' + ' '.join(attrs)) if attrs else ''
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self.result.append('<' + tag + attrs + end_diagonal + '>')
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def handle_endtag(self, tag):
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if self.start and tag == self.start[len(self.start) - 1]:
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self.result.append('</' + tag + '>')
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self.start.pop()
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def handle_data(self, data):
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self.result.append(self._htmlspecialchars(data))
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def handle_entityref(self, name):
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if name.isalpha():
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self.result.append("&%s;" % name)
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def handle_charref(self, name):
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if name.isdigit():
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self.result.append("&#%s;" % name)
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def node_default(self, attrs):
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attrs = self._common_attr(attrs)
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return attrs
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def node_a(self, attrs):
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attrs = self._common_attr(attrs)
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attrs = self._get_link(attrs, "href")
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attrs = self._set_attr_default(attrs, "target", "_blank")
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attrs = self._limit_attr(attrs, {
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"target": ["_blank", "_self"]
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})
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return attrs
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def node_embed(self, attrs):
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attrs = self._common_attr(attrs)
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attrs = self._get_link(attrs, "src")
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attrs = self._limit_attr(attrs, {
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"type": ["application/x-shockwave-flash"],
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"wmode": ["transparent", "window", "opaque"],
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"play": ["true", "false"],
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"loop": ["true", "false"],
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"menu": ["true", "false"],
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"allowfullscreen": ["true", "false"]
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})
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attrs["allowscriptaccess"] = "never"
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attrs["allownetworking"] = "none"
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return attrs
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def _true_url(self, url):
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prog = re.compile(r"^(http|https|ftp)://.+", re.I | re.S)
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if prog.match(url):
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return url
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else:
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return "http://%s" % url
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def _true_style(self, style):
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if style:
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style = re.sub(r"(\\|&#|/\*|\*/)", "_", style)
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style = re.sub(r"e.*x.*p.*r.*e.*s.*s.*i.*o.*n", "_", style)
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return style
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def _get_style(self, attrs):
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if "style" in attrs:
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attrs["style"] = self._true_style(attrs.get("style"))
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return attrs
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def _get_link(self, attrs, name):
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if name in attrs:
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attrs[name] = self._true_url(attrs[name])
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return attrs
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def _wash_attr(self, attrs, tag):
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if tag in self.tags_own_attrs:
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other = self.tags_own_attrs.get(tag)
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else:
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other = []
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if attrs:
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for key, value in copy.deepcopy(attrs).items():
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if key not in self.common_attrs + other:
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del attrs[key]
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return attrs
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def _common_attr(self, attrs):
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attrs = self._get_style(attrs)
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return attrs
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def _set_attr_default(self, attrs, name, default=''):
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if name not in attrs:
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attrs[name] = default
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return attrs
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def _limit_attr(self, attrs, limit={}):
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for (key, value) in limit.items():
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if key in attrs and attrs[key] not in value:
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del attrs[key]
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return attrs
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def _htmlspecialchars(self, html):
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return html.replace("<", "<") \
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.replace(">", ">") \
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.replace('"', """) \
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.replace("'", "'")
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if "__main__" == __name__:
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parser = XssHtml()
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parser.feed("""<p><img src=1 onerror=alert(/xss/)></p><div class="left">
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<a href='javascript:prompt(1)'><br />hehe</a></div>
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<p id="test" onmouseover="alert(1)">>M<svg>
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<a href="https://www.baidu.com" target="self">MM</a></p>
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<embed src='javascript:alert(/hehe/)' allowscriptaccess=always />""")
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parser.close()
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print(parser.getHtml())
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