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SECURITY ALERT: Corrected regular expressions for URL and email fields.

Certain email addresses/URLs could trigger a catastrophic backtracking situation, causing 100% CPU and server overload. If deliberately triggered, this could be the basis of a denial-of-service attack.

This security vulnerability was disclosed in public, so we're skipping our
normal security release process to get the fix out as soon as possible.

This is a security related update. A full announcement, as well as backports for the 1.1.X and 1.0.X series will follow.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11603 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit 9f8287a3f145fe5cbe71ef5573ea8898404727ad 1 parent 8aee95c
@jacobian jacobian authored
Showing with 35 additions and 2 deletions.
  1. +2 −2 django/forms/fields.py
  2. +33 −0 tests/regressiontests/forms/fields.py
View
4 django/forms/fields.py
@@ -421,7 +421,7 @@ def clean(self, value):
email_re = re.compile(
r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*" # dot-atom
r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"' # quoted-string
- r')@(?:[A-Z0-9]+(?:-*[A-Z0-9]+)*\.)+[A-Z]{2,6}$', re.IGNORECASE) # domain
+ r')@(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?$', re.IGNORECASE) # domain
class EmailField(RegexField):
default_error_messages = {
@@ -532,7 +532,7 @@ def clean(self, data, initial=None):
url_re = re.compile(
r'^https?://' # http:// or https://
- r'(?:(?:[A-Z0-9]+(?:-*[A-Z0-9]+)*\.)+[A-Z]{2,6}|' #domain...
+ r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?|' #domain...
r'localhost|' #localhost...
r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
r'(?::\d+)?' # optional port
View
33 tests/regressiontests/forms/fields.py
@@ -767,6 +767,13 @@
>>> f.clean('example@valid-with-hyphens.com')
u'example@valid-with-hyphens.com'
+# Check for runaway regex security problem. This will take for-freeking-ever
+# if the security fix isn't in place.
+>>> f.clean('viewx3dtextx26qx3d@yahoo.comx26latlngx3d15854521645943074058')
+Traceback (most recent call last):
+ ...
+ValidationError: [u'Enter a valid e-mail address.']
+
>>> f = EmailField(required=False)
>>> f.clean('')
u''
@@ -972,6 +979,32 @@
Traceback (most recent call last):
...
ValidationError: [u'Enter a valid URL.']
+>>> f.clean('.')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid URL.']
+>>> f.clean('com.')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid URL.']
+>>> f.clean('http://example.com.')
+u'http://example.com./'
+>>> f.clean('example.com.')
+u'http://example.com./'
+
+# hangs "forever" if catastrophic backtracking in ticket:#11198 not fixed
+>>> f.clean('http://%s' % ("X"*200,))
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid URL.']
+
+# a second test, to make sure the problem is really addressed, even on
+# domains that don't fail the domain label length check in the regex
+>>> f.clean('http://%s' % ("X"*60,))
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid URL.']
+
>>> f.clean('http://.com')
Traceback (most recent call last):
...
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