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|
From: Chris Lamb <lamby@debian.org>
Date: Sat, 13 Jun 2020 15:31:18 +0100
Subject: CVE-2020-13254
---
django/core/cache/__init__.py | 4 ++--
django/core/cache/backends/base.py | 33 +++++++++++++++++++++------------
django/core/cache/backends/memcached.py | 24 ++++++++++++++++++++++--
3 files changed, 45 insertions(+), 16 deletions(-)
diff --git a/django/core/cache/__init__.py b/django/core/cache/__init__.py
index 26897ff..dc377a9 100644
--- a/django/core/cache/__init__.py
+++ b/django/core/cache/__init__.py
@@ -17,13 +17,13 @@ from threading import local
from django.conf import settings
from django.core import signals
from django.core.cache.backends.base import (
- BaseCache, CacheKeyWarning, InvalidCacheBackendError,
+ BaseCache, CacheKeyWarning, InvalidCacheBackendError, InvalidCacheKey,
)
from django.utils.module_loading import import_string
__all__ = [
'cache', 'DEFAULT_CACHE_ALIAS', 'InvalidCacheBackendError',
- 'CacheKeyWarning', 'BaseCache',
+ 'CacheKeyWarning', 'BaseCache', 'InvalidCacheKey',
]
DEFAULT_CACHE_ALIAS = 'default'
diff --git a/django/core/cache/backends/base.py b/django/core/cache/backends/base.py
index a07a34e..688ffb8 100644
--- a/django/core/cache/backends/base.py
+++ b/django/core/cache/backends/base.py
@@ -24,6 +24,10 @@ DEFAULT_TIMEOUT = object()
MEMCACHE_MAX_KEY_LENGTH = 250
+class InvalidCacheKey(ValueError):
+ pass
+
+
def default_key_func(key, key_prefix, version):
"""
Default function to generate keys.
@@ -233,18 +237,8 @@ class BaseCache(object):
backend. This encourages (but does not force) writing backend-portable
cache code.
"""
- if len(key) > MEMCACHE_MAX_KEY_LENGTH:
- warnings.warn(
- 'Cache key will cause errors if used with memcached: %r '
- '(longer than %s)' % (key, MEMCACHE_MAX_KEY_LENGTH), CacheKeyWarning
- )
- for char in key:
- if ord(char) < 33 or ord(char) == 127:
- warnings.warn(
- 'Cache key contains characters that will cause errors if '
- 'used with memcached: %r' % key, CacheKeyWarning
- )
- break
+ for warning in memcache_key_warnings(key):
+ warnings.warn(warning, CacheKeyWarning)
def incr_version(self, key, delta=1, version=None):
"""Adds delta to the cache version for the supplied key. Returns the
@@ -270,3 +264,18 @@ class BaseCache(object):
def close(self, **kwargs):
"""Close the cache connection"""
pass
+
+
+def memcache_key_warnings(key):
+ if len(key) > MEMCACHE_MAX_KEY_LENGTH:
+ yield (
+ 'Cache key will cause errors if used with memcached: %r '
+ '(longer than %s)' % (key, MEMCACHE_MAX_KEY_LENGTH)
+ )
+ for char in key:
+ if ord(char) < 33 or ord(char) == 127:
+ yield (
+ 'Cache key contains characters that will cause errors if '
+ 'used with memcached: %r' % key,
+ )
+ break
diff --git a/django/core/cache/backends/memcached.py b/django/core/cache/backends/memcached.py
index ee6b3b7..80395e6 100644
--- a/django/core/cache/backends/memcached.py
+++ b/django/core/cache/backends/memcached.py
@@ -3,7 +3,9 @@
import pickle
import time
-from django.core.cache.backends.base import DEFAULT_TIMEOUT, BaseCache
+from django.core.cache.backends.base import (
+ DEFAULT_TIMEOUT, BaseCache, InvalidCacheKey, memcache_key_warnings,
+)
from django.utils import six
from django.utils.encoding import force_str
from django.utils.functional import cached_property
@@ -69,10 +71,12 @@ class BaseMemcachedCache(BaseCache):
def add(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
return self._cache.add(key, value, self.get_backend_timeout(timeout))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
val = self._cache.get(key)
if val is None:
return default
@@ -80,16 +84,20 @@ class BaseMemcachedCache(BaseCache):
def set(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
if not self._cache.set(key, value, self.get_backend_timeout(timeout)):
# make sure the key doesn't keep its old value in case of failure to set (memcached's 1MB limit)
self._cache.delete(key)
def delete(self, key, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
self._cache.delete(key)
def get_many(self, keys, version=None):
new_keys = [self.make_key(x, version=version) for x in keys]
+ for key in new_keys:
+ self.validate_key(key)
ret = self._cache.get_multi(new_keys)
if ret:
_ = {}
@@ -104,6 +112,7 @@ class BaseMemcachedCache(BaseCache):
def incr(self, key, delta=1, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
# memcached doesn't support a negative delta
if delta < 0:
return self._cache.decr(key, -delta)
@@ -122,6 +131,7 @@ class BaseMemcachedCache(BaseCache):
def decr(self, key, delta=1, version=None):
key = self.make_key(key, version=version)
+ self.validate_key(key)
# memcached doesn't support a negative delta
if delta < 0:
return self._cache.incr(key, -delta)
@@ -142,15 +152,25 @@ class BaseMemcachedCache(BaseCache):
safe_data = {}
for key, value in data.items():
key = self.make_key(key, version=version)
+ self.validate_key(key)
safe_data[key] = value
self._cache.set_multi(safe_data, self.get_backend_timeout(timeout))
def delete_many(self, keys, version=None):
- self._cache.delete_multi(self.make_key(key, version=version) for key in keys)
+ to_delete = []
+ for key in to_delete:
+ key = self.make_key(key, version=version)
+ self.validate_key(key)
+ to_delete.append(key)
+ self._cache.delete_multi(to_delete)
def clear(self):
self._cache.flush_all()
+ def validate_key(self, key):
+ for warning in memcache_key_warnings(key):
+ raise InvalidCacheKey(warning)
+
class MemcachedCache(BaseMemcachedCache):
"An implementation of a cache binding using python-memcached"
|
