我希望允许用户发布图片,因此需要将|safe
添加到模板标记,并使用beautifulsoap将this代码段列入白名单。
但是,我想知道如何避免下列潜在的恶意属性?
<img src="puppy.png" onload="(function(){/* do bad stuff */}());" />
更新 请注意,上面链接的代码段有一些XSS漏洞,提到here
答案 0 :(得分:5)
您还需要检查属性白名单。
使用美丽的汤3 :
def safe_html(html):
tag_whitelist = ['img']
attr_whitelist = ['src', 'alt', 'width', 'height']
soup = BeautifulSoup(html)
for tag in soup.findAll():
if tag.name.lower() in tag_whitelist:
tag.attrs = [a for a in tag.attrs if a[0].lower() in attr_whitelist]
else:
tag.unwrap()
# scripts can be executed from comments in some cases (citation needed)
comments = soup.findAll(text=lambda text:isinstance(text, Comment))
for comment in comments:
comment.extract()
return unicode(soup)
使用美丽的汤4 :
def safe_html(html):
tag_whitelist = ['img']
attr_whitelist = ['src', 'alt', 'width', 'height']
soup = BeautifulSoup(html)
for tag in soup.find_all():
if tag.name.lower() in tag_whitelist:
tag.attrs = { name: value for name, value in tag.attrs.items()
if name.lower() in attr_whitelist }
else:
tag.unwrap()
# scripts can be executed from comments in some cases (citation needed)
comments = soup.find_all(text=lambda text:isinstance(text, Comment))
for comment in comments:
comment.extract()
return unicode(soup)