Fix heap-buffer-overflow write in CUT RLE parser#40
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JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
Open
Fix heap-buffer-overflow write in CUT RLE parser#40JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
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When decompressing a CUT (Dr. Halo) format image, a zero-count byte in the RLE stream causes the scanline pointer to be decremented (bits -= pitch) without verifying that the pointer remains within the allocated bitmap. If the header declares height=1 but the RLE data contains multiple zero-count markers, the pointer underflows below the heap allocation, leading to an out-of-bounds write via the subsequent memset or read_proc call. Add a bounds check before the decrement to ensure the pointer does not move past the first scanline. CWE-787 (Out-of-bounds Write) Found during academic security research.
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Summary
The CUT (Dr. Halo) format parser allocates a bitmap from the file header (
width * height). During RLE decompression, a zero-count byte triggersbits -= pitchto move to the previous scanline. If the header declaresheight=1but the RLE data contains multiple zero-count markers, the scanline pointer underflows below the heap allocation, causing an out-of-bounds write on the subsequentmemsetorread_proccall.Root cause
PluginCUT.cppline 169:bits -= pitch;— no check thatbitsremains within the allocated bitmap before decrementing.Fix
Add a bounds check before the decrement: verify that
bitsis at leastpitchbytes above the start of the bitmap data. If not, break out of the decompression loop.Metadata
width=0x230B,height=0x0001(available on request)memcpyatPluginCUT.cpp:193, triggered by_MemoryReadProc