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Validate indexed BMP palette counts before reading - #105
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## Summary `gsKit_texture_bmp` allocates fixed-size color lookup tables for 4-bpp and 8-bpp images, but uses the BMP header's `ColorUsed` value without checking it before reading palette data. A malformed file can therefore make `fread` write past the allocated CLUT. Validate indexed-color palette counts before allocating or reading the palette. Reject counts larger than `2^BitCount`, and interpret a zero count as the format-defined maximum for 4-bpp and 8-bpp BMPs. ## Testing - Build gsKit with the PS2 toolchain. - Verify that valid 4-bpp and 8-bpp BMPs with `ColorUsed` set to zero or the maximum palette size still load. - Verify that malformed 4-bpp (`ColorUsed = 17`) and 8-bpp (`ColorUsed = 257`) BMPs are rejected before palette data is read.
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Summary
gsKit_texture_bmpallocates fixed-size color lookup tables for 4-bpp and 8-bpp images, but uses the BMP header'sColorUsedvalue without checking it before reading palette data. A malformed file can therefore makefreadwrite past the allocated CLUT.Validate indexed-color palette counts before allocating or reading the palette. Reject counts larger than
2^BitCount, and interpret a zero count as the format-defined maximum for 4-bpp and 8-bpp BMPs.Testing
ColorUsedset to zero or the maximum palette size still load.ColorUsed = 17) and 8-bpp (ColorUsed = 257) BMPs are rejected before palette data is read.