Emulated USB Drive is always 253MB in `size`?

[psparc82]

Hi,

I'm using the FAT32DiskImage class and I'm passing it a size parameter of 512MB yet the drive always shows up as 253MB under Linux:

img = FAT32DiskImage(1024 * 1024 * 512, verbose=2)

$ df -h .
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdc1       253M  253M     0 100% /media/ubuntu/Facedancer

Is there a limitation to what size can be used? Ideally I'd like to use as much as 1GB but I can try with 512MB

[jamchamb]

The sector indices and number of sectors per FAT in FAT32DiskImage are hard-coded such that a FAT can only address ~253 MB.
I have a patch for an older version of Facedancer here to support slightly larger files: jamchamb@69630e1 (I haven't tested this in a while though)

I believe the math is (4,033 sectors per FAT * 512 bytes per sector/cluster) / 4 bytes per FAT32 entry = 516,224 FAT entries, times 512 = 264,306,688 bytes.