Track data and src on canvas_jpeg_error_mgr to free on libjpeg longjmp#2581
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iurisilvio wants to merge 1 commit into
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Track data and src on canvas_jpeg_error_mgr to free on libjpeg longjmp#2581iurisilvio wants to merge 1 commit into
iurisilvio wants to merge 1 commit into
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If libjpeg calls error_exit during jpeg_read_scanlines (corrupt or truncated JPEG that decoded the header but fails in the scan), it longjmps back to the setjmp point in loadJPEGFromBuffer. That bypasses the cleanup at the bottom of decodeJPEGIntoSurface, leaking both 'data' (width * height * 4) and 'src' (width * output_components). Store both pointers on the canvas_jpeg_error_mgr so the error handler can delete[] them before longjmp. Also reorder cleanup to destroy libjpeg state and free src before creating the cairo surface, so the success path is symmetric with the new failure path.
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Fixes #2577.
When libjpeg calls
error_exitduringjpeg_read_scanlines()(the common failure for corrupt or truncated JPEGs where the header decodes but the entropy-coded scan data is malformed), it doeslongjmpback to the setjmp inloadJPEGFromBuffer. That bypasses the cleanup code indecodeJPEGIntoSurface, leaking bothdata(width * height * 4bytes) andsrc(scanline buffer) on every call.Standalone repro on
canvas@3.2.3shows ~4 MiB leaked per call — process OOMs in seconds under sustained load on malformed JPEGs. Full numbers in #2577.The fix tracks both pointers on
canvas_jpeg_error_mgrso the error handler candelete[]them before the longjmp. The decode flow is reordered sojpeg_destroy_decompressanddelete[] srchappen before the cairo surface is created — that way the success path's ownership transfer is symmetric with the failure path, with no double-free.