Messing around with MBRs

gistfile1.txt

Messing around with MBRs is fun.  For example, you can make overlapping
partitions.  Well, not with fdisk, of course.  You need to make the volume to
clone first, then shuffle it around with dd like so:

dd if=/dev/sda bs=1 skip=446 seek=462 of=/dev/sda count=16
dd if=/dev/sda bs=1 skip=446 seek=478 of=/dev/sda count=16
dd if=/dev/sda bs=1 skip=446 seek=494 of=/dev/sda count=16

Once this is done, kick the kernel to reread the MBR (I usually do this with
fdisk because it amuses me that it will read and save this wacky partition
table but won't let you create it) and away we go!

root@archiso ~ # fdisk -l /dev/sda
Disk /dev/sda: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xb25baaf1

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048    16777215     8387584   83  Linux
/dev/sda2            2048    16777215     8387584   83  Linux
/dev/sda3            2048    16777215     8387584   83  Linux
/dev/sda4            2048    16777215     8387584   83  Linux
root@archiso ~ # od -x /dev/sda1
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*

130 root@archiso ~ # od -x /dev/sda2
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*

130 root@archiso ~ # od -x /dev/sda3
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*

130 root@archiso ~ # od -x /dev/sda4
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*

130 root@archiso ~ # yes lolo >/dev/sda1
130 root@archiso ~ # head /dev/sda2
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
root@archiso ~ # head /dev/sda3
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
root@archiso ~ # head /dev/sda4
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo
lolo

More bad ideas to come.