Mercurial > dropbear
comparison test/test_aslr.py @ 1861:2b3a8026a6ce
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.
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Sun, 30 Jan 2022 10:14:56 +0800 |
| parents | |
| children | b550845e500b |
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| 1860:5001e9c5641f | 1861:2b3a8026a6ce |
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| 1 from pathlib import Path | |
| 2 import sys | |
| 3 | |
| 4 from test_dropbear import * | |
| 5 | |
| 6 def test_reexec(request, dropbear): | |
| 7 """ | |
| 8 Tests that two consecutive connections have different address layouts. | |
| 9 This indicates that re-exec makes ASLR work | |
| 10 """ | |
| 11 cmd = (Path(request.node.fspath).parent / "parent_dropbear_map.py").resolve() | |
| 12 r = dbclient(request, cmd, capture_output=True, text=True) | |
| 13 map1 = r.stdout.rstrip() | |
| 14 print(r.stderr, file=sys.stderr) | |
| 15 r.check_returncode() | |
| 16 | |
| 17 r = dbclient(request, cmd, capture_output=True, text=True) | |
| 18 map2 = r.stdout.rstrip() | |
| 19 print(r.stderr, file=sys.stderr) | |
| 20 r.check_returncode() | |
| 21 | |
| 22 print(map1) | |
| 23 print(map2) | |
| 24 # expect something like | |
| 25 # "563174d59000-563174d5d000 r--p 00000000 00:29 4242372 /home/matt/src/dropbear/build/dropbear" | |
| 26 assert map1.endswith('/dropbear') | |
| 27 assert ' r--p ' in map1 | |
| 28 a1 = map1.split()[0] | |
| 29 a2 = map2.split()[0] | |
| 30 print(a1) | |
| 31 print(a2) | |
| 32 # relocation addresses should differ | |
| 33 assert a1 != a2 | |
| 34 |