Commit Graph

23 Commits

Author SHA1 Message Date
Scott Kuhl
97c25e988e
tproxy: Skip firewall chains if packets have local destination. (#578)
If you use the tproxy method with a large subnet (such as 0/0), then
(1) you may not receive UDP packets that sshuttle/tproxy can handle
and (2) you are unable to connect to your machine using an IP that
your computer recognizes as its own.

To resolve those issues, any traffic to an IP that the host knows is
local, does not go through the sshuttle chains.
2021-01-04 09:05:32 +11:00
Scott Kuhl
7fc33c0020 Refactor debug, log and Fatal messages.
This commit rewrites the log() function so that it will append a
newline at the end of the message if none is present. It doesn't make
sense to print a log message without a newline since the next log
message (which will write a prefix) expects to be starting at the
beginning of a line.

Although it isn't strictly necessary, this commit also removes any
newlines at the ends of messages. If I missed any, including the
newline at the end of the message will continue to work as it did
before.

Previously, some calls were missing the newline at the end even though
including it was necessary for subsequent messages to appear
correctly.

This code also cleans up some redundant prefixes. The log() method
will prepend the prefix and the different processes should set their
prefix as soon as they start.

Multiline messages are still supported (although the prefix for the
additional lines was changed to match the length of the prefix used
for the first line).
2021-01-01 19:32:48 +11:00
Scott Kuhl
6d4261e3f9 Refactor automatic method selection.
Add an "is_supported()" function to the different methods so that each
method can include whatever logic they wish to indicate if they are
supported on a particular machine. Previously, methods/__init__.py
contained all of the logic for selecting individual methods. Now, it
iterates through a list of possible options and stops on the first
method that it finds that is_supported().

Currently, the decision is made based on the presence of programs in
the PATH. In the future, things such as the platform sshuttle is
running on could be considered.
2020-12-28 10:21:56 +11:00
Brian May
9b036fc689
Merge pull request #552 from skuhl/systemd-resolved
Intercept DNS requests sent by systemd-resolved.
2020-11-04 16:55:09 +11:00
Scott Kuhl
8461e08bc3 Make server and client handle resolv.conf differently.
The server should just read from resolv.conf to find DNS servers to
use. This restores this behavior after the previous commit changed it.

The client now reads both /etc/resolv.conf and
/run/systemd/resolve/resolv.conf. The latter is required to more
reliably intercept regular DNS requests that systemd-resolved makes.
2020-11-03 20:27:57 -05:00
Scott Kuhl
34f538ff98 Merge branch 'master' into which-fix to resolve merge conflict. 2020-10-26 17:24:32 -04:00
Scott Kuhl
68c9c9bbcd Improve consistency of PATH, environments, and which()
This patch attempts to fix (or aid in debugging) issue #350.

sshuttle didn't explicitly search /sbin and /usr/sbin and they may be
missing in the user's PATH. If PATH is missing, these folders wouldn't
be searched either. There was also a program_exists function which is
redundant to which(). This consolidates everything into the helpers.py
file.

This patch introduces get_path() to return PATH + some extra hardcoded
paths. A new get_env() function can be called to create a consistent
environment when calling external programs. The new which() wrapper
function also ensures we use the same set of paths.

If -vv is supplied, messages clearly indicate the programs we are
looking for, if they are found, and where we looked if we failed to
find them.

I haven't tested the changes to ipfw or pf.
2020-10-23 20:33:20 -04:00
Scott Kuhl
6d86e44fb4 IPv6 support in nft method.
This works for me but needs testing by others. Remember to specify a
::0/0 subnet or similar to route IPv6 through sshuttle.

I'm adding this to nft before nat since it is not sshuttle's default
method on Linux. Documentation updates may be required too.

This patch uses the ipaddress module, but that appears to be included
since Python 3.3.
2020-10-21 17:47:07 -04:00
Scott Kuhl
bc24ed359a Make nat and nft rules consistent; improve rule ordering.
First, check if TTL indicates we should ignore packet (instead of
checking in multiple rules later). Also, nft method didn't do this at
all. Now, nft matches the behavior of nat.

Second, forward DNS traffic (we may need to intercept traffic to
localhost if a DNS server is running on localhost).

Third, ignore any local traffic packets. (Previously, we ignored local
traffic except DNS and then had the DNS rules). The nft method didn't
do this previously at all. It now matches the behavior of nat.

Lastly, list the subnets to redirect and/or exclude. This step is left
unchanged. Excluding the local port that we are listening on is
redundant with the third step, but should cause no harm.

In summary, this ordering simplifies the rules in nat and eliminates
differences that previously existed between nat and nft.
2020-10-21 11:51:39 -04:00
Brian May
c3016f2d90
Merge pull request #541 from skuhl/use-all-ips
When subnets and excludes are specified with hostnames, use all IPs.
2020-10-20 07:56:50 +11:00
Scott Kuhl
e1106a33a9 Only write /etc/hosts when necessary.
Without this patch, sshuttle 'restores' /etc/hosts even if it didn't
make any modifications to it. This can be confirmed by running without
--auto-hosts and confirming that the modification time of /etc/hosts
is unchanged while sshuttle is running, but is updated when sshuttle
exits (and a debug2() message is printed indicating the file is
written).

I'm not aware of the previous behavior causing problems. However,
writing an important file unnecessarily as root should be avoided.
2020-10-19 00:17:37 -04:00
Scott Kuhl
c2b10465e7 Remove localhost test since it can resolve to either IPv4, IPv6, or both in any particular order 2020-10-17 15:56:23 -04:00
Scott Kuhl
cfe14f2498 fix flake8 issues in updated tests 2020-10-17 15:40:28 -04:00
Scott Kuhl
cb53d8a150 Make tests for parse_subnetport() expect lists & update expected error messages in tests 2020-10-17 15:36:16 -04:00
Joshua Li
d0f0aa9f17 remove version_info based branching 2020-06-03 14:30:37 +10:00
Norman Rasmussen
502b36e990 Add tproxy udp port mark filter that was missed in #144, fixes #367. 2019-10-13 11:45:04 +11:00
Nick Sokolov
a7193f508a Fix capturing of local DNS servers
Regression was introduced in #337 that is skipping all local traffic,
including DNS. This change makes UDP port 53 (DNS) LOCAL traffic to be
treated as special case.

Fixes #357
2019-09-22 10:37:49 +10:00
Anthony Cornehl
21ef365c59 The size of pf_rule grew in OpenBSD 6.4 2019-09-22 10:29:28 +10:00
Daniel Jeffery
3e2ad68796 Fix tests for existing PR-312 (#337)
* use addrtype match to return the LOCAL trafik

* Add assertion for the new LOCAL firewall rule added in PR 312.

* Fix linter complaints
2019-06-08 12:12:21 +10:00
Bastian Venthur
3bfb975ed9 Fix/pep8 (#277)
* re-organized imports according to pep8
* fixed all remaining pep8 issues
* moved common config into setup.cfg, additionally test `tests`
* removed --select=X -- the errors selected where by default not in
  flake8's --ignore list so effectively had no effect
* update .travis.yml to reflect changes in tox.ini
* make travis just use tox in order to avoid code duplaction
* replace py.test with pytest
* fixed .travis.yml
* try different pypy toxenv
* hopefully fixed testenv for pypy
* added pypy basepython, removed unused python2.6
* install dev package before testing (fixes missing coverage)
* fixed empty exception pass blocks with noqa
* Added dummy log message on empty try-except-pass blocks to make dodacy happy :(
* Replaced Exception with BaseException
2019-02-11 09:59:13 +11:00
João Vieira
ca41026c89 Changes pf exclusion rules precedence
Before this change, in pf, exclusions used a pass out quick which gave
them higher precedence than any other rule independent of subnet width.
As reported in #265 this causes exclusion from one instance of sshuttle
to also take effect on other instances because quick aborts the
evaluation of rules across all anchors.

This commit changes the precedence of rules so quick can now be
dropped. The new order is defined by the following rule, from
subnet_weight:

"We need to go from smaller, more specific, port ranges, to larger,
less-specific, port ranges. At each level, we order by subnet
width, from most-specific subnets (largest swidth) to
least-specific. On ties, excludes come first."
2018-11-03 12:24:32 +11:00
João Vieira
7a54d12f80 Fixes support for OpenBSD (6.1+) (#282)
* Fixes support for OpenBSD (6.1+)

As reported in #219, new versions of OpenBSD ship with a different
pfioc_rule struct. This commit adjusts the offset to match the new struct.

* Fixes tests for OpenBSD 6.1+
2018-10-23 07:31:29 +11:00
Bastian Venthur
842768f9cf Moved sshuttle/tests into tests to.
Having the tests in a `tests` directory in root is the most common
approach. Also moved pytest's conftest.py into `tests` making the
fixture available for client and server tests.
2018-10-17 20:52:04 +11:00