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python - Django url arg 不能包含 NUL (0x00) 字符

问题描述

我目前正在测试我们网站的安全漏洞，我自己的安全背景非常有限。

运行以下请求时：

http://127.0.0.1:8000/stuff/?template=%2Fe%00

我看到了错误（下面的完整堆栈跟踪）：

Exception Type: ValueError at /stuff/
Exception Value: A string literal cannot contain NUL (0x00) characters.

这似乎是验证 url args 的问题，并且不应允许字符 0x00 (null)。我相当确定在谷歌的 gruyere中我看到一些字符应该被转义，但转义 null 似乎很奇怪。

我当然可以尝试/排除第 92 行/code/stuff/views.py，但这无疑会在其他地方出现。

我的问题是：

堆栈跟踪：

File "/usr/local/lib/python3.6/site-packages/django/core/handlers/exception.py" in inner
  34.             response = get_response(request)

File "/usr/local/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
  115.                 response = self.process_exception_by_middleware(e, request)

File "/usr/local/lib/python3.6/site-packages/django/core/handlers/base.py" in _get_response
  113.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/usr/local/lib/python3.6/site-packages/django/views/generic/base.py" in view
  71.             return self.dispatch(request, *args, **kwargs)

File "/usr/local/lib/python3.6/site-packages/django/views/generic/base.py" in dispatch
  97.         return handler(request, *args, **kwargs)
File "/usr/local/lib/python3.6/site-packages/django/views/generic/list.py" in get
  157.         context = self.get_context_data()

File "/code/stuff/views.py" in get_context_data
  92.         context = super(StuffListView, self).get_context_data(**kwargs)

File "/usr/local/lib/python3.6/site-packages/django/views/generic/list.py" in get_context_data
  119.             paginator, page, queryset, is_paginated = self.paginate_queryset(queryset, page_size)

File "/usr/local/lib/python3.6/site-packages/django/views/generic/list.py" in paginate_queryset
  69.             page = paginator.page(page_number)

File "/usr/local/lib/python3.6/site-packages/django/core/paginator.py" in page
  70.         number = self.validate_number(number)

File "/usr/local/lib/python3.6/site-packages/django/core/paginator.py" in validate_number
  48.         if number > self.num_pages:

File "/usr/local/lib/python3.6/site-packages/django/utils/functional.py" in __get__
  80.         res = instance.__dict__[self.name] = self.func(instance)

File "/usr/local/lib/python3.6/site-packages/django/core/paginator.py" in num_pages
  97.         if self.count == 0 and not self.allow_empty_first_page:

File "/usr/local/lib/python3.6/site-packages/django/utils/functional.py" in __get__
  80.         res = instance.__dict__[self.name] = self.func(instance)

File "/usr/local/lib/python3.6/site-packages/django/core/paginator.py" in count
  91.             return c()

File "/usr/local/lib/python3.6/site-packages/django/db/models/query.py" in count
  392.         return self.query.get_count(using=self.db)

File "/usr/local/lib/python3.6/site-packages/django/db/models/sql/query.py" in get_count
  504.         number = obj.get_aggregation(using, ['__count'])['__count']

File "/usr/local/lib/python3.6/site-packages/django/db/models/sql/query.py" in get_aggregation
  489.         result = compiler.execute_sql(SINGLE)

File "/usr/local/lib/python3.6/site-packages/django/db/models/sql/compiler.py" in execute_sql
  1100.             cursor.execute(sql, params)

File "/usr/local/lib/python3.6/site-packages/django/db/backends/utils.py" in execute
  99.             return super().execute(sql, params)

File "/usr/local/lib/python3.6/site-packages/django/db/backends/utils.py" in execute
  67.         return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

File "/usr/local/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute_with_wrappers
  76.         return executor(sql, params, many, context)

File "/usr/local/lib/python3.6/site-packages/django/db/backends/utils.py" in _execute
  84.                 return self.cursor.execute(sql, params)

Exception Type: ValueError at /stuff/
Exception Value: A string literal cannot contain NUL (0x00) characters.

标签： pythondjangosecurityurl

解决方案

根据回溯，问题不在于 URL 参数不能包含%00，而是当它通过 传递到您正在使用的数据库时Paginator，数据库驱动程序正在抱怨事情。

从错误来看，您可能正在使用 Postgres。（请参阅此相关问题：Django + Postgres: A string literal cannot contain NUL (0x00) characters）

如果你愿意，你可以设置一个中间件来拒绝任何和所有包含%00.

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