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Altered the behavior of URLField to avoid a potential DOS vector, and to avoid potential leakage of local filesystem data. A security announcement will be made shortly.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16760 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee
2011-09-10 00:47:00 +00:00
parent 33076af6f2
commit 5f287f75f2
11 changed files with 107 additions and 43 deletions

View File

@@ -1,3 +1,4 @@
import platform
import re
import urllib2
import urlparse
@@ -41,10 +42,6 @@ class RegexValidator(object):
if not self.regex.search(smart_unicode(value)):
raise ValidationError(self.message, code=self.code)
class HeadRequest(urllib2.Request):
def get_method(self):
return "HEAD"
class URLValidator(RegexValidator):
regex = re.compile(
r'^(?:http|ftp)s?://' # http:// or https://
@@ -54,7 +51,8 @@ class URLValidator(RegexValidator):
r'(?::\d+)?' # optional port
r'(?:/?|[/?]\S+)$', re.IGNORECASE)
def __init__(self, verify_exists=False, validator_user_agent=URL_VALIDATOR_USER_AGENT):
def __init__(self, verify_exists=False,
validator_user_agent=URL_VALIDATOR_USER_AGENT):
super(URLValidator, self).__init__()
self.verify_exists = verify_exists
self.user_agent = validator_user_agent
@@ -79,6 +77,13 @@ class URLValidator(RegexValidator):
url = value
if self.verify_exists:
import warnings
warnings.warn(
"The URLField verify_exists argument has intractable security "
"and performance issues. Accordingly, it has been deprecated.",
DeprecationWarning
)
headers = {
"Accept": "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5",
"Accept-Language": "en-us,en;q=0.5",
@@ -90,21 +95,37 @@ class URLValidator(RegexValidator):
broken_error = ValidationError(
_(u'This URL appears to be a broken link.'), code='invalid_link')
try:
req = HeadRequest(url, None, headers)
u = urllib2.urlopen(req)
req = urllib2.Request(url, None, headers)
req.get_method = lambda: 'HEAD'
#Create an opener that does not support local file access
opener = urllib2.OpenerDirector()
#Don't follow redirects, but don't treat them as errors either
error_nop = lambda *args, **kwargs: True
http_error_processor = urllib2.HTTPErrorProcessor()
http_error_processor.http_error_301 = error_nop
http_error_processor.http_error_302 = error_nop
http_error_processor.http_error_307 = error_nop
handlers = [urllib2.UnknownHandler(),
urllib2.HTTPHandler(),
urllib2.HTTPDefaultErrorHandler(),
urllib2.FTPHandler(),
http_error_processor]
try:
import ssl
handlers.append(urllib2.HTTPSHandler())
except:
#Python isn't compiled with SSL support
pass
map(opener.add_handler, handlers)
opener.http_error_301 = lambda: True
if platform.python_version_tuple() >= (2, 6):
opener.open(req, timeout=10)
else:
opener.open(req)
except ValueError:
raise ValidationError(_(u'Enter a valid URL.'), code='invalid')
except urllib2.HTTPError, e:
if e.code in (405, 501):
# Try a GET request (HEAD refused)
# See also: http://www.w3.org/Protocols/rfc2616/rfc2616.html
try:
req = urllib2.Request(url, None, headers)
u = urllib2.urlopen(req)
except:
raise broken_error
else:
raise broken_error
except: # urllib2.URLError, httplib.InvalidURL, etc.
raise broken_error