Execute a program with CLI instruction

Question

I am trying to enhance my (poor) knowledge of ASM by doing crackmes. I stumbled across an odd one, an ELF 32bit.
Its name is "bootme", but if I launch it, it does a segfault.

I used gdb and noticed that the segfault is due to the instruction "CLI". Indeed an user (event root) is not allowed to execute this instruction. Only the kernel is allowed.

Here's my question: How can I execute this program?

missimer · Accepted Answer · 2015-07-17 17:51:12Z

1

This program is most likely mean to be either a bootloader or as an operating system kernel so you cannot run it as a user space application. If it is an OS kernel you could probably create a grub or u-boot (most likely GRUB, since it is x86) image and launch it in a virtual machine, emulator or on real hardware.

answered Jul 17, 2015 at 17:51

missimer

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