Regression: Python 3.5.0 shutil.copy2 doesn't raise PermissionError on Windows 7

[nre3976]

BPO	25213
Nosy	@pfmoore, @tjguk, @zware, @eryksun, @zooba

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/zooba'
closed_at = <Date 2015-09-23.01:24:05.735>
created_at = <Date 2015-09-22.13:48:40.183>
labels = ['OS-windows']
title = "Regression: Python 3.5.0 shutil.copy2 doesn't raise PermissionError on Windows 7"
updated_at = <Date 2015-09-23.01:24:05.734>
user = 'https://bugs.python.org/nre3976'

bugs.python.org fields:

activity = <Date 2015-09-23.01:24:05.734>
actor = 'steve.dower'
assignee = 'steve.dower'
closed = True
closed_date = <Date 2015-09-23.01:24:05.735>
closer = 'steve.dower'
components = ['Windows']
creation = <Date 2015-09-22.13:48:40.183>
creator = 'nre3976'
dependencies = []
files = []
hgrepos = []
issue_num = 25213
keywords = ['3.5regression']
message_count = 4.0
messages = ['251322', '251336', '251346', '251364']
nosy_count = 7.0
nosy_names = ['paul.moore', 'tim.golden', 'python-dev', 'zach.ware', 'eryksun', 'steve.dower', 'nre3976']
pr_nums = []
priority = 'high'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue25213'
versions = ['Python 3.5']

[nre3976]

Python 3.5.0 shutil.copy2 doesn't raise PermissionError when it does not have permission to copy a file (tested on Windows 7):

C:\Users\X\Desktop>C:\Users\X\AppData\Local\Programs\Python\Python35-32\python.exe
Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:16:59) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import shutil
>>> shutil.copy2("test.txt", "/")
'/test.txt'
>>> shutil.copy2("test.txt", "C:\\")
'C:\\test.txt'

NB: The file is not copied.

Python 3.4.3 does raise PermissionError:

C:\Users\X\Desktop>C:\Python34\python.exe
Python 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:44:40) [MSC v.1600 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import shutil
>>> shutil.copy2("test.txt", "/")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python34\lib\shutil.py", line 245, in copy2
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "C:\Python34\lib\shutil.py", line 109, in copyfile
    with open(dst, 'wb') as fdst:
PermissionError: [Errno 13] Permission denied: '/test.txt'
>>> shutil.copy2("test.txt", "C:\\")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python34\lib\shutil.py", line 245, in copy2
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "C:\Python34\lib\shutil.py", line 109, in copyfile
    with open(dst, 'wb') as fdst:
PermissionError: [Errno 13] Permission denied: 'C:\\test.txt'

[eryksun]

This issue doesn't pertain to the 64-bit version.

    C:\Temp>py -3.5
    Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:27:37) 
    [MSC v.1900 64 bit (AMD64)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import shutil
    >>> shutil.copy2('test.txt', 'C:\\')
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "C:\Program Files\Python 3.5\lib\shutil.py", line 251, in copy2
        copyfile(src, dst, follow_symlinks=follow_symlinks)
      File "C:\Program Files\Python 3.5\lib\shutil.py", line 115, in copyfile
        with open(dst, 'wb') as fdst:
    PermissionError: [Errno 13] Permission denied: 'C:\\test.txt'

In the 32-bit version, creating a file in the system root directory gets virtualized when the user doesn't have write access. It's not specific to shutil.copy2.

    C:\Temp>py -3.5-32
    Python 3.5.0 (v3.5.0:374f501f4567, Sep 13 2015, 02:16:59) 
    [MSC v.1900 32 bit (Intel)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>> open('C:\\test.txt', 'w').close()
    >>> import pathlib
    >>> pathlib.Path('C:\\test.txt').resolve()
    WindowsPath('C:/Users/usradm/AppData/Local/VirtualStore/test.txt')

You can verify in the task manager's details tab that UAC Virtualization is enabled for 32-bit python.exe and disabled for 64-bit python.exe. The problem is that the manifest is missing the requestedExecutionLevel, which should be present and set to "asInvoker". This is discussed in the MSDN article New UAC Technologies for Windows Vista.

    >>> os.system('sigcheck -q -m "%s"' % sys.executable)
    c:\users\usradm\appdata\local\programs\python\python35-32\python.exe:
            Verified:       Signed
            Signing date:   2:17 AM 9/13/2015
            Publisher:      Python Software Foundation
            Description:    Python
            Product:        Python
            Prod version:   3.5.0
            File version:   3.5.0
            MachineType:    32-bit
            Manifest:
    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
      <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
        <application>
          <supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}"/>
          <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>
          <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
          <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>
          <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
        </application>
      </compatibility>
    </assembly>

3.4's manifest sets the requestedExecutionLevel:

    C:\Temp>py -3.4-32
    Python 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:43:06) 
    [MSC v.1600 32 bit (Intel)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import os, sys
    >>> os.system('sigcheck -q -m "%s"' % sys.executable)
    c:\users\usradm\appdata\local\programs\python\python34-32\python.exe:
            Verified:       Unsigned
            Link date:      9:43 PM 2/24/2015
            Publisher:      n/a
            Description:    n/a
            Product:        n/a
            Prod version:   n/a
            File version:   n/a
            MachineType:    32-bit
            Manifest:
    <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
      <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
        <security>
          <requestedPrivileges>
            <requestedExecutionLevel level="asInvoker" uiAccess="false"></requestedExecutionLevel>
          </requestedPrivileges>
        </security>
      </trustInfo>
    </assembly> 

[zooba]

Confirmed. I have a trivial fix coming to restore the requestedExecutionLevel.

[python-dev]

New changeset b7f0f1d1e923 by Steve Dower in branch '3.5':
Issue bpo-25213: Restores requestedExecutionLevel to manifest to disable UAC virtualization.
https://hg.python.org/cpython/rev/b7f0f1d1e923