From 310a894471516eb1e3a89bde25e521a408558f85 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Nussbaumer?= <rn@google.com>
Date: Tue, 24 Aug 2010 13:54:01 +0200
Subject: [PATCH] Adding host key verification to setup-ssh
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Signed-off-by: RenΓ© Nussbaumer <rn@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
---
tools/setup-ssh | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/tools/setup-ssh b/tools/setup-ssh
index e5a512bf1..2dd2c9ab6 100755
--- a/tools/setup-ssh
+++ b/tools/setup-ssh
@@ -177,6 +177,7 @@ def ParseOptions():
" <node...>"), prog=program)
parser.add_option(cli.DEBUG_OPT)
parser.add_option(cli.VERBOSE_OPT)
+ parser.add_option(cli.NOSSH_KEYCHECK_OPT)
default_key = ssh.GetUserFiles(constants.GANETI_RUNAS)[0]
parser.add_option(optparse.Option("-f", dest="private_key",
default=default_key,
@@ -296,6 +297,22 @@ def LoginViaKeys(transport, username, keys):
return False
+def LoadKnownHosts():
+ """Loads the known hosts
+
+ @return L{paramiko.util.load_host_keys} dict
+
+ """
+ homedir = utils.GetHomeDir(constants.GANETI_RUNAS)
+ known_hosts = os.path.join(homedir, ".ssh", "known_hosts")
+
+ try:
+ return paramiko.util.load_host_keys(known_hosts)
+ except EnvironmentError:
+ # We didn't found the path, silently ignore and return an empty dict
+ return {}
+
+
def main():
"""Main routine.
@@ -309,6 +326,7 @@ def main():
passwd = None
username = constants.GANETI_RUNAS
ssh_port = netutils.GetDaemonPort("ssh")
+ host_keys = LoadKnownHosts()
# Below, we need to join() the transport objects, as otherwise the
# following happens:
@@ -322,6 +340,28 @@ def main():
for host in args:
transport = paramiko.Transport((host, ssh_port))
transport.start_client()
+ server_key = transport.get_remote_server_key()
+ keytype = server_key.get_name()
+
+ our_server_key = host_keys.get(host, {}).get(keytype, None)
+ if options.ssh_key_check:
+ if not our_server_key:
+ hexified_key = ssh.FormatParamikoFingerprint(
+ server_key.get_fingerprint())
+ msg = ("Unable to verify hostkey of host %s: %s. Do you want to accept"
+ " it?" % (host, hexified_key))
+
+ if cli.AskUser(msg):
+ our_server_key = server_key
+
+ if our_server_key != server_key:
+ logging.error("Unable to verify identity of host. Aborting")
+ transport.close()
+ transport.join()
+ # TODO: Run over all hosts, fetch the keys and let them verify from the
+ # user beforehand then proceed with actual work later on
+ raise paramiko.SSHException("Unable to verify identity of host")
+
try:
if LoginViaKeys(transport, username, all_keys):
logging.info("Authenticated to %s via public key", host)
--
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