Fix handling of subsampled channels in PyOpenEXR#2542
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readPixels() allocated the pixel array with the full data-window shape (height, width) for all channels, but for subsampled channels the EXR reader only wrote width/xSampling values per row and height/ySampling rows total. The unwritten rows/columns retained stale heap contents that were returned to Python as valid pixel data. Fix: shrink c_shape to the actual sampled dimensions before allocating, using ceiling division consistent with EXR's sampling convention. The framebuffer yStride calculation already used shape[1]/C.xSampling, so no stride change is needed. Addresses https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-c32g-9w8w-3px6 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Signed-off-by: Cary Phillips <cary@ilm.com>
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readPixels() allocated the pixel array with the full data-window shape (height, width) for all channels, but for subsampled channels the EXR reader only wrote width/xSampling values per row and height/ySampling rows total. The unwritten rows/columns retained stale heap contents that were returned to Python as valid pixel data.
Fix: shrink c_shape to the actual sampled dimensions before allocating, using ceiling division consistent with EXR's sampling convention. The framebuffer yStride calculation already used shape[1]/C.xSampling, so no stride change is needed.
Addresses https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-c32g-9w8w-3px6