Renaming Custom Python Properties is Incorrect #98973

New Issue

jon denning · 2022-06-18T14:14:17+02:00

jon denning commented

2022-06-18 14:14:17 +02:00

Renaming a custom Python property does not work as expected. In particular, if the property is renamed to a shorter name, the property's new name retains the trailing characters of previous name. This issue does not appear if new name has same length or is longer. Likely, the \0 terminator isn't getting written.

To reproduce: open default scene, switch to the Python Console, and type the following.

>>> C.scene['foo'] = {'bar': 42}     # create custom python property with name 'foo'
>>> list(C.scene.keys())             # print out correct names of custom properties

['foo']

>>> C.scene['foo'].name = 'baz'      # rename 'foo' property to 'baz', same length as 'foo'
>>> list(C.scene.keys())             # print out correct names of custom properties

['baz']

>>> C.scene['baz'].name = 'bazey'    # rename 'baz' property to 'bazey', a LONGER name
>>> list(C.scene.keys())             # print out correct names of custom properties

['bazey']

>>> C.scene['bazey'].name = 'foo'    # rename 'bazey' property to 'foo', a SHORTER name
>>> list(C.scene.keys())             # print out INCORRECT names of custom properties

['fooey']

>>> C.scene['foo'].name              # surprisingly, this is an ERROR!

Traceback (most recent call last):
  File "<blender_console>", line 1, in <module>
KeyError: 'bpy_struct[key]: key "foo" not found'

>>> C.scene['fooey'].name

'fooey'

>>> C.scene['fooey'].name = 'foo\0'  # rename with explicitly inserted '\0'
>>> list(C.scene.keys())             # print out correct names of custom properties

['foo']

Interestingly, data can be hidden in the names... (possible security issue?)

# create a secret message
C.scene['1 A SECRET MESSAGE IS HIDDEN HERE!'] = {'foo': 42}
list(C.scene.keys())
# ['1 A SECRET MESSAGE IS HIDDEN HERE!']

# hide the secret message
C.scene['1 A SECRET MESSAGE IS HIDDEN HERE!'].name = '1\0'
list(C.scene.keys())
- ['1']
- the secret message is hidden from Python (all asserts below pass)
assert '1' in C.scene
assert '1\0' in C.scene
assert '1\0NOT ORIGINAL SECRET MESSAGE' in C.scene

- IMPORTANT: at this point, we can save as .blend, close and reopen blender,
- then open saved .blend file.  this means that the secret message
#            persists across sessions!  can even run asserts above!

# now, reveal the original secret message
C.scene['1'].name = '1 '  # don't even need to know what the secret message was!
list(C.scene.keys())
# ['1 A SECRET MESSAGE IS HIDDEN HERE!']

Renaming a custom Python property does not work as expected. In particular, if the property is renamed to a *shorter* name, the property's new name retains the trailing characters of previous name. This issue does not appear if new name has same length or is longer. Likely, the `\0` terminator isn't getting written. To reproduce: open default scene, switch to the Python Console, and type the following. ``` >>> C.scene['foo'] = {'bar': 42} # create custom python property with name 'foo' >>> list(C.scene.keys()) # print out correct names of custom properties ['foo'] >>> C.scene['foo'].name = 'baz' # rename 'foo' property to 'baz', same length as 'foo' >>> list(C.scene.keys()) # print out correct names of custom properties ['baz'] >>> C.scene['baz'].name = 'bazey' # rename 'baz' property to 'bazey', a LONGER name >>> list(C.scene.keys()) # print out correct names of custom properties ['bazey'] >>> C.scene['bazey'].name = 'foo' # rename 'bazey' property to 'foo', a SHORTER name >>> list(C.scene.keys()) # print out INCORRECT names of custom properties ['fooey'] >>> C.scene['foo'].name # surprisingly, this is an ERROR! Traceback (most recent call last): File "<blender_console>", line 1, in <module> KeyError: 'bpy_struct[key]: key "foo" not found' >>> C.scene['fooey'].name 'fooey' >>> C.scene['fooey'].name = 'foo\0' # rename with explicitly inserted '\0' >>> list(C.scene.keys()) # print out correct names of custom properties ['foo'] ``` Interestingly, data can be hidden in the names... (possible security issue?) ``` # create a secret message C.scene['1 A SECRET MESSAGE IS HIDDEN HERE!'] = {'foo': 42} list(C.scene.keys()) # ['1 A SECRET MESSAGE IS HIDDEN HERE!'] # hide the secret message C.scene['1 A SECRET MESSAGE IS HIDDEN HERE!'].name = '1\0' list(C.scene.keys()) - ['1'] - the secret message is hidden from Python (all asserts below pass) assert '1' in C.scene assert '1\0' in C.scene assert '1\0NOT ORIGINAL SECRET MESSAGE' in C.scene - IMPORTANT: at this point, we can save as .blend, close and reopen blender, - then open saved .blend file. this means that the secret message # persists across sessions! can even run asserts above! # now, reveal the original secret message C.scene['1'].name = '1 ' # don't even need to know what the secret message was! list(C.scene.keys()) # ['1 A SECRET MESSAGE IS HIDDEN HERE!'] ```

jon denning commented

2022-06-18 14:14:17 +02:00

Added subscriber: @gfxcoder

Jesse Yurkovich commented

2022-06-22 03:03:07 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser removed the

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Renaming Custom Python Properties is Incorrect #98973