Mercurial > dropbear
annotate test/test_aslr.py @ 1930:299f4f19ba19
Add /usr/sbin and /sbin to default root PATH
When dropbear is used in a very restricted environment (such as in a
initrd), the default user shell is often also very restricted
and doesn't take care of setting the PATH so the user ends up
with the PATH set by dropbear. Unfortunately, dropbear always
sets "/usr/bin:/bin" as default PATH even for the root user
which should have /usr/sbin and /sbin too.
For a concrete instance of this problem, see the "Remote Unlocking"
section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/
It speaks of a bug in the initramfs script because it's written "blkid"
instead of "/sbin/blkid"... this is just because the scripts from the
initramfs do not expect to have a PATH without the sbin directories and
because dropbear is not setting the PATH appropriately for the root user.
I'm thus suggesting to use the attached patch to fix this misbehaviour (I
did not test it, but it's easy enough). It might seem anecdotic but
multiple Kali users have been bitten by this.
From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
| author | Raphael Hertzog <hertzog@debian.org> |
|---|---|
| date | Mon, 09 Jul 2018 16:27:53 +0200 |
| parents | 1c9215154d4a |
| children |
| rev | line source |
|---|---|
| 1861 | 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 """ | |
| 1863 | 11 map_script = (Path(request.node.fspath).parent / "parent_dropbear_map.py").resolve() |
| 12 # run within the same venv, for python deps | |
| 13 activate = own_venv_command() | |
| 14 cmd = f"{activate}; {map_script}" | |
| 15 print(cmd) | |
| 1861 | 16 r = dbclient(request, cmd, capture_output=True, text=True) |
| 17 map1 = r.stdout.rstrip() | |
| 18 print(r.stderr, file=sys.stderr) | |
| 19 r.check_returncode() | |
| 20 | |
| 21 r = dbclient(request, cmd, capture_output=True, text=True) | |
| 22 map2 = r.stdout.rstrip() | |
| 23 print(r.stderr, file=sys.stderr) | |
| 24 r.check_returncode() | |
| 25 | |
| 26 print(map1) | |
| 27 print(map2) | |
| 28 # expect something like | |
| 29 # "563174d59000-563174d5d000 r--p 00000000 00:29 4242372 /home/matt/src/dropbear/build/dropbear" | |
|
1865
d940f8007a45
Fix testing with dropbearmulti
Matt Johnston <matt@ucc.asn.au>
parents:
1863
diff
changeset
|
30 assert map1.endswith('/dropbear') or map1.endswith('/dropbearmulti') |
| 1861 | 31 a1 = map1.split()[0] |
| 32 a2 = map2.split()[0] | |
| 33 print(a1) | |
| 34 print(a2) | |
| 35 # relocation addresses should differ | |
| 36 assert a1 != a2 | |
| 37 |