Scaling up 1x1 pixel image reads past buffer bounds #70356

New Issue

Campbell Barton · 2019-09-29T16:28:22+02:00

Campbell Barton commented

2019-09-29 16:28:22 +02:00

This Python script causes an ASAN error:

import imbuf
imbuf.new((1, 1)).resize((2, 2), 'BILINEAR')

Although this isn't limited to Python, the error happens when IMB_scaleImBuf is called on a 1x1 pixel image from anywhere in Blender.

asan_imbuf.txt

Currently the function assumes there is always a 'next' pixel.

This Python script causes an ASAN error: ``` import imbuf imbuf.new((1, 1)).resize((2, 2), 'BILINEAR') ``` Although this isn't limited to Python, the error happens when `IMB_scaleImBuf` is called on a 1x1 pixel image from anywhere in Blender. [asan_imbuf.txt](https://archive.blender.org/developer/F7779834/asan_imbuf.txt) Currently the function assumes there is always a 'next' pixel.

Campbell Barton commented

2019-09-29 16:28:22 +02:00

Added subscriber: @ideasman42

blender-admin commented

2019-09-29 16:28:22 +02:00

#89868 was marked as duplicate of this issue

Pedro Reis commented

2019-10-04 14:29:04 +02:00

Added subscriber: @pedroreis.ad

Pedro Reis commented

2019-10-04 18:40:53 +02:00

I can't replicate this on my machine, could you provide some more instructions? It runs the script fine on my PC, so I might be doing something wrong

Campbell Barton commented

2019-10-04 19:18:54 +02:00

The error happens with address sanitizer enabled, use WITH_COMPILER_ASAN, although it's not available on all platforms.

Just from checking the code you can see it assumes a second pixel exists.

The error happens with address sanitizer enabled, use `WITH_COMPILER_ASAN`, although it's not available on all platforms. Just from checking the code you can see it assumes a second pixel exists.

Pedro Reis commented

2019-10-04 20:33:04 +02:00

Oh, I hadn't used that flag for the compilation, thanks! What would be the expected outcome of this, I don't quite understand what is the ImBuf structure, even after toying with it this summer.

Sybren A. Stüvel commented

2020-02-11 12:15:50 +01:00

Added subscriber: @dr.sybren

Sybren A. Stüvel commented

2020-02-11 12:15:50 +01:00

Changed status from 'Confirmed' to: 'Needs User Info'

Sybren A. Stüvel commented

2020-02-11 12:15:50 +01:00

I can't reproduce this in current master (be8879718e), even with WITH_COMPILER_ASAN. @ideasman42 is this still an issue?

I can't reproduce this in current master (be8879718e24e417d299eb298b8a9d4d2ca324ee), even with `WITH_COMPILER_ASAN`. @ideasman42 is this still an issue?

Campbell Barton commented

2020-02-20 05:31:29 +01:00

Tested and it's still an issue, although since this report 'BILINEAR' needs to be passed to redo this error (updated code snipped).