Fix CVE-2017-14176:
https://bugs.launchpad.net/bzr/+bug/1710979
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-14176
Patch copied from Debian's Bazaar package version bzr_2.7.0+bzr6619-7+deb9u1:
https://alioth.debian.org/scm/loggerhead/pkg-bazaar/bzr/2.7/revision/4204
Description: Prevent SSH command line options from being specified in bzr+ssh:// URLs
Bug: https://bugs.launchpad.net/brz/+bug/1710979
Bug-Debian: https://bugs.debian.org/874429
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-14176
Forwarded: no
Author: Jelmer Vernooij <jelmer@jelmer.uk>
Last-Update: 2017-11-26
=== modified file 'bzrlib/tests/test_ssh_transport.py'
--- old/bzrlib/tests/test_ssh_transport.py 2010-10-07 12:45:51 +0000
+++ new/bzrlib/tests/test_ssh_transport.py 2017-08-20 01:59:20 +0000
@@ -22,6 +22,7 @@
SSHCorpSubprocessVendor,
LSHSubprocessVendor,
SSHVendorManager,
+ StrangeHostname,
)
@@ -161,6 +162,19 @@
class SubprocessVendorsTests(TestCase):
+ def test_openssh_command_tricked(self):
+ vendor = OpenSSHSubprocessVendor()
+ self.assertEqual(
+ vendor._get_vendor_specific_argv(
+ "user", "-oProxyCommand=blah", 100, command=["bzr"]),
+ ["ssh", "-oForwardX11=no", "-oForwardAgent=no",
+ "-oClearAllForwardings=yes",
+ "-oNoHostAuthenticationForLocalhost=yes",
+ "-p", "100",
+ "-l", "user",
+ "--",
+ "-oProxyCommand=blah", "bzr"])
+
def test_openssh_command_arguments(self):
vendor = OpenSSHSubprocessVendor()
self.assertEqual(
@@ -171,6 +185,7 @@
"-oNoHostAuthenticationForLocalhost=yes",
"-p", "100",
"-l", "user",
+ "--",
"host", "bzr"]
)
@@ -184,9 +199,16 @@
"-oNoHostAuthenticationForLocalhost=yes",
"-p", "100",
"-l", "user",
- "-s", "host", "sftp"]
+ "-s", "--", "host", "sftp"]
)
+ def test_openssh_command_tricked(self):
+ vendor = SSHCorpSubprocessVendor()
+ self.assertRaises(
+ StrangeHostname,
+ vendor._get_vendor_specific_argv,
+ "user", "-oProxyCommand=host", 100, command=["bzr"])
+
def test_sshcorp_command_arguments(self):
vendor = SSHCorpSubprocessVendor()
self.assertEqual(
@@ -209,6 +231,13 @@
"-s", "sftp", "host"]
)
+ def test_lsh_command_tricked(self):
+ vendor = LSHSubprocessVendor()
+ self.assertRaises(
+ StrangeHostname,
+ vendor._get_vendor_specific_argv,
+ "user", "-oProxyCommand=host", 100, command=["bzr"])
+
def test_lsh_command_arguments(self):
vendor = LSHSubprocessVendor()
self.assertEqual(
@@ -231,6 +260,13 @@
"--subsystem", "sftp", "host"]
)
+ def test_plink_command_tricked(self):
+ vendor = PLinkSubprocessVendor()
+ self.assertRaises(
+ StrangeHostname,
+ vendor._get_vendor_specific_argv,
+ "user", "-oProxyCommand=host", 100, command=["bzr"])
+
def test_plink_command_arguments(self):
vendor = PLinkSubprocessVendor()
self.assertEqual(
=== modified file 'bzrlib/transport/ssh.py'
--- old/bzrlib/transport/ssh.py 2015-07-31 01:04:41 +0000
+++ new/bzrlib/transport/ssh.py 2017-08-20 01:59:20 +0000
@@ -46,6 +46,10 @@
from paramiko.sftp_client import SFTPClient
+class StrangeHostname(errors.BzrError):
+ _fmt = "Refusing to connect to strange SSH hostname %(hostname)s"
+
+
SYSTEM_HOSTKEYS = {}
BZR_HOSTKEYS = {}
@@ -360,6 +364,11 @@
# tests, but beware of using PIPE which may hang due to not being read.
_stderr_target = None
+ @staticmethod
+ def _check_hostname(arg):
+ if arg.startswith('-'):
+ raise StrangeHostname(hostname=arg)
+
def _connect(self, argv):
# Attempt to make a socketpair to use as stdin/stdout for the SSH
# subprocess. We prefer sockets to pipes because they support
@@ -424,9 +433,9 @@
if username is not None:
args.extend(['-l', username])
if subsystem is not None:
- args.extend(['-s', host, subsystem])
+ args.extend(['-s', '--', host, subsystem])
else:
- args.extend([host] + command)
+ args.extend(['--', host] + command)
return args
register_ssh_vendor('openssh', OpenSSHSubprocessVendor())
@@ -439,6 +448,7 @@
def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
command=None):
+ self._check_hostname(host)
args = [self.executable_path, '-x']
if port is not None:
args.extend(['-p', str(port)])
@@ -460,6 +470,7 @@
def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
command=None):
+ self._check_hostname(host)
args = [self.executable_path]
if port is not None:
args.extend(['-p', str(port)])
@@ -481,6 +492,7 @@
def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
command=None):
+ self._check_hostname(host)
args = [self.executable_path, '-x', '-a', '-ssh', '-2', '-batch']
if port is not None:
args.extend(['-P', str(port)])
