Safeexec Security Tests | Computer Science Circles

Example

you can change the process name

# this changes the thread name
# run
# ps Hcx -ef
# to see the effect

def set_proc_name(newname):
    from ctypes import cdll, byref, create_string_buffer
    libc = cdll.LoadLibrary('libc.so.6')
    buff = create_string_buffer(len(newname)+1)
    buff.value = newname
    libc.prctl(15, byref(buff), 0, 0, 0)

def get_proc_name():
    from ctypes import cdll, byref, create_string_buffer
    libc = cdll.LoadLibrary('libc.so.6')
    buff = create_string_buffer(128)
    # 16 == PR_GET_NAME from <linux/prctl.h>
    libc.prctl(16, byref(buff), 0, 0, 0)
    return buff.value

import sys
# sys.argv[0] == 'python'

# outputs 'python'
print(get_proc_name())

set_proc_name(bytes('this is the new process name', 'utf-8'))

# outputs 'this is'...
print(get_proc_name())

Example

allowed and denied things

import os
from inspect import currentframe
print(os.getcwd()) #should work
print(os.getuid(), os.geteuid()) #should work
print(os.getgid(), os.getegid(), 1000, "should be same")
try:
    print("contents of /lib", os.listdir('/lib')) #should work
except OSError as E:
    print('ok')

print("currrent filename", currentframe().f_code.co_filename)
    
try:
    print('bad', os.listdir(os.getcwd())) #should work
except OSError as E:
    print("ok:", E)

try:
    print("bad:", os.listdir('/'))
except OSError as E:
    print("ok:", E)

try:
    print("contents of /scratch:", os.listdir('/scratch'))
except OSError as E:
    print("ok:", E)

try:
    print(len(open('safeexec.out').read()))
except IOError as E:
    print("ok:", E)

print(len(open(currentframe().f_code.co_filename).read()))
print(len(open('usercode').read()))
print(len(open('/static/_UTILITIES.py').read()))

try:
    print(open('/README').read())
except IOError as E:
    print('ok')

try:
    print(len(open('usercode').write('test')))
except IOError as E:
    print("ok:", E)

try:
    print(len(open('/static/_UTILITIES.py').write('test')))
except IOError as E:
    print("ok:", E)