dropbear/test/test_aslr.py
Matt Johnston c7b7c9a99d Add re-exec for server
This allows ASLR to re-randomize the address
space for every connection, preventing some
vulnerabilities from being exploitable by
repeated probing.

Overhead (memory and time) is yet to be confirmed.

At present this is only enabled on Linux. Other BSD platforms
with fexecve() would probably also work though have not been tested.
2022-01-30 10:14:56 +08:00

35 lines
944 B
Python

from pathlib import Path
import sys
from test_dropbear import *
def test_reexec(request, dropbear):
"""
Tests that two consecutive connections have different address layouts.
This indicates that re-exec makes ASLR work
"""
cmd = (Path(request.node.fspath).parent / "parent_dropbear_map.py").resolve()
r = dbclient(request, cmd, capture_output=True, text=True)
map1 = r.stdout.rstrip()
print(r.stderr, file=sys.stderr)
r.check_returncode()
r = dbclient(request, cmd, capture_output=True, text=True)
map2 = r.stdout.rstrip()
print(r.stderr, file=sys.stderr)
r.check_returncode()
print(map1)
print(map2)
# expect something like
# "563174d59000-563174d5d000 r--p 00000000 00:29 4242372 /home/matt/src/dropbear/build/dropbear"
assert map1.endswith('/dropbear')
assert ' r--p ' in map1
a1 = map1.split()[0]
a2 = map2.split()[0]
print(a1)
print(a2)
# relocation addresses should differ
assert a1 != a2