Fix heap-buffer-overflow write in PICT UnpackPictRow#41
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JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
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Fix heap-buffer-overflow write in PICT UnpackPictRow#41JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
JorgeBarredo14 wants to merge 1 commit intodanoli3:masterfrom
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The PackBits decompression loop in UnpackPictRow advances pCurPixel by the decoded run length without verifying that the destination remains within the allocated line buffer. A crafted PICT file with run lengths that exceed the scanline width causes memset or read_proc to write past the end of pLineBuf. Clamp the decoded length to the remaining buffer space before each write operation, in both the packed-data and unpacked-data code paths. CWE-787 (Out-of-bounds Write) Found during academic security research.
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Summary
The PackBits decompression loop in
UnpackPictRowadvancespCurPixelby the decoded run length without verifying that the destination remains within the allocated line buffer (pLineBuf, sized torowBytes). A crafted PICT file with run lengths that exceed the scanline width causesmemset(packed path) orread_proc(unpacked path) to write past the end of the buffer.Root cause
PluginPICT.cpplines 562 and 571: the decodedlenis used directly inmemset/read_procwithout clamping to the remaining buffer space.Fix
Clamp the decoded length to the remaining buffer space (
pLineBuf + rowBytes - pCurPixel) before each write operation, in both the packed-data and unpacked-data code paths. Skip the write entirely if no space remains.Metadata