proc_flag

Kernel module which generates random /proc/flag files

Example

$ dmesg -wH &
$ clear
$ sudo insmod kflags.ko
$ [Mar29 18:17] Loaded /proc/flag module
[Mar29 18:17] Loaded /proc/flag module
cat /proc/flag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$ cat /proc/flag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$ sudo rmmod kflags.ko
[ +18.618607] Unloaded /proc/flag module
[ +18.618607] Unloaded /proc/flag module
$ cat /proc/flag
cat: /proc/flag: No such file or directory

Installation

The included makefile will build the kernel module and load it with insmod. You must have root access and will be prompted for your password if necessary.

$ make
make -C /lib/modules/4.15.0-20-generic/build M=/mnt/hgfs/6265-info-sec-lab/kflags modules
make[1]: Entering directory '/usr/src/linux-headers-4.15.0-20-generic'
Makefile:976: "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel"
  Building modules, stage 2.
  MODPOST 1 modules
make[1]: Leaving directory '/usr/src/linux-headers-4.15.0-20-generic'
sudo rmmod kflags.ko || true
rmmod: ERROR: Module kflags is not currently loaded
sudo insmod kflags.ko
[Mar29 18:20] Loaded /proc/flag module
[Mar29 18:20] Loaded /proc/flag module

Configuration

By default, the module will load /proc/flag, and generate random flags of size 1024.

• To change /proc/flag into /proc/other, modify #define PROC_NAME
• To change flag size, modify #define FLAG_SIZE