X-Git-Url: https://code.grnet.gr/git/ganeti-local/blobdiff_plain/70d9e3d8aa9a7ec1da6c0fe0e345cfb1cfeeb0c2..33c730a22222f266a726a47ddc0e553ec012060d:/lib/ssh.py?ds=sidebyside diff --git a/lib/ssh.py b/lib/ssh.py index 2caab46..dba13df 100644 --- a/lib/ssh.py +++ b/lib/ssh.py @@ -1,7 +1,7 @@ # # -# Copyright (C) 2006, 2007 Google Inc. +# Copyright (C) 2006, 2007, 2010, 2011 Google Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by @@ -25,189 +25,309 @@ import os +import logging -from ganeti import logger from ganeti import utils from ganeti import errors from ganeti import constants +from ganeti import netutils +from ganeti import pathutils +from ganeti import vcluster +from ganeti import compat + + +def GetUserFiles(user, mkdir=False, dircheck=True, kind=constants.SSHK_DSA, + _homedir_fn=None): + """Return the paths of a user's SSH files. + + @type user: string + @param user: Username + @type mkdir: bool + @param mkdir: Whether to create ".ssh" directory if it doesn't exist + @type dircheck: bool + @param dircheck: Whether to check if ".ssh" directory exists + @type kind: string + @param kind: One of L{constants.SSHK_ALL} + @rtype: tuple; (string, string, string) + @return: Tuple containing three file system paths; the private SSH key file, + the public SSH key file and the user's C{authorized_keys} file + @raise errors.OpExecError: When home directory of the user can not be + determined + @raise errors.OpExecError: Regardless of the C{mkdir} parameters, this + exception is raised if C{~$user/.ssh} is not a directory and C{dircheck} + is set to C{True} + """ + if _homedir_fn is None: + _homedir_fn = utils.GetHomeDir + + user_dir = _homedir_fn(user) + if not user_dir: + raise errors.OpExecError("Cannot resolve home of user '%s'" % user) + + if kind == constants.SSHK_DSA: + suffix = "dsa" + elif kind == constants.SSHK_RSA: + suffix = "rsa" + else: + raise errors.ProgrammerError("Unknown SSH key kind '%s'" % kind) -__all__ = ["SSHCall", "CopyFileToNode", "VerifyNodeHostname", - "KNOWN_HOSTS_OPTS", "BATCH_MODE_OPTS", "ASK_KEY_OPTS"] + ssh_dir = utils.PathJoin(user_dir, ".ssh") + if mkdir: + utils.EnsureDirs([(ssh_dir, constants.SECURE_DIR_MODE)]) + elif dircheck and not os.path.isdir(ssh_dir): + raise errors.OpExecError("Path %s is not a directory" % ssh_dir) + return [utils.PathJoin(ssh_dir, base) + for base in ["id_%s" % suffix, "id_%s.pub" % suffix, + "authorized_keys"]] -KNOWN_HOSTS_OPTS = [ - "-oGlobalKnownHostsFile=%s" % constants.SSH_KNOWN_HOSTS_FILE, - "-oUserKnownHostsFile=/dev/null", - ] -# Note: BATCH_MODE conflicts with ASK_KEY -BATCH_MODE_OPTS = [ - "-oEscapeChar=none", - "-oBatchMode=yes", - "-oStrictHostKeyChecking=yes", - ] +def GetAllUserFiles(user, mkdir=False, dircheck=True, _homedir_fn=None): + """Wrapper over L{GetUserFiles} to retrieve files for all SSH key types. -ASK_KEY_OPTS = [ - "-oStrictHostKeyChecking=ask", - "-oEscapeChar=none", - "-oHashKnownHosts=no", - ] + See L{GetUserFiles} for details. + + @rtype: tuple; (string, dict with string as key, tuple of (string, string) as + value) + + """ + helper = compat.partial(GetUserFiles, user, mkdir=mkdir, dircheck=dircheck, + _homedir_fn=_homedir_fn) + result = [(kind, helper(kind=kind)) for kind in constants.SSHK_ALL] + authorized_keys = [i for (_, (_, _, i)) in result] -def GetUserFiles(user, mkdir=False): - """Return the paths of a user's ssh files. + assert len(frozenset(authorized_keys)) == 1, \ + "Different paths for authorized_keys were returned" - The function will return a triplet (priv_key_path, pub_key_path, - auth_key_path) that are used for ssh authentication. Currently, the - keys used are DSA keys, so this function will return: - (~user/.ssh/id_dsa, ~user/.ssh/id_dsa.pub, - ~user/.ssh/authorized_keys). + return (authorized_keys[0], + dict((kind, (privkey, pubkey)) + for (kind, (privkey, pubkey, _)) in result)) - If the optional parameter mkdir is True, the ssh directory will be - created if it doesn't exist. - Regardless of the mkdir parameters, the script will raise an error - if ~user/.ssh is not a directory. +class SshRunner: + """Wrapper for SSH commands. """ - user_dir = utils.GetHomeDir(user) - if not user_dir: - raise errors.OpExecError("Cannot resolve home of user %s" % user) + def __init__(self, cluster_name, ipv6=False): + """Initializes this class. + + @type cluster_name: str + @param cluster_name: name of the cluster + @type ipv6: bool + @param ipv6: If true, force ssh to use IPv6 addresses only + + """ + self.cluster_name = cluster_name + self.ipv6 = ipv6 + + def _BuildSshOptions(self, batch, ask_key, use_cluster_key, + strict_host_check, private_key=None, quiet=True): + """Builds a list with needed SSH options. + + @param batch: same as ssh's batch option + @param ask_key: allows ssh to ask for key confirmation; this + parameter conflicts with the batch one + @param use_cluster_key: if True, use the cluster name as the + HostKeyAlias name + @param strict_host_check: this makes the host key checking strict + @param private_key: use this private key instead of the default + @param quiet: whether to enable -q to ssh + + @rtype: list + @return: the list of options ready to use in L{utils.process.RunCmd} + + """ + options = [ + "-oEscapeChar=none", + "-oHashKnownHosts=no", + "-oGlobalKnownHostsFile=%s" % pathutils.SSH_KNOWN_HOSTS_FILE, + "-oUserKnownHostsFile=/dev/null", + "-oCheckHostIp=no", + ] + + if use_cluster_key: + options.append("-oHostKeyAlias=%s" % self.cluster_name) + + if quiet: + options.append("-q") + + if private_key: + options.append("-i%s" % private_key) + + # TODO: Too many boolean options, maybe convert them to more descriptive + # constants. + + # Note: ask_key conflicts with batch mode + if batch: + if ask_key: + raise errors.ProgrammerError("SSH call requested conflicting options") + + options.append("-oBatchMode=yes") + + if strict_host_check: + options.append("-oStrictHostKeyChecking=yes") + else: + options.append("-oStrictHostKeyChecking=no") + + else: + # non-batch mode + + if ask_key: + options.append("-oStrictHostKeyChecking=ask") + elif strict_host_check: + options.append("-oStrictHostKeyChecking=yes") + else: + options.append("-oStrictHostKeyChecking=no") - ssh_dir = os.path.join(user_dir, ".ssh") - if not os.path.lexists(ssh_dir): - if mkdir: - try: - os.mkdir(ssh_dir, 0700) - except EnvironmentError, err: - raise errors.OpExecError("Can't create .ssh dir for user %s: %s" % - (user, str(err))) - elif not os.path.isdir(ssh_dir): - raise errors.OpExecError("path ~%s/.ssh is not a directory" % user) + if self.ipv6: + options.append("-6") - return [os.path.join(ssh_dir, base) - for base in ["id_dsa", "id_dsa.pub", "authorized_keys"]] + return options + def BuildCmd(self, hostname, user, command, batch=True, ask_key=False, + tty=False, use_cluster_key=True, strict_host_check=True, + private_key=None, quiet=True): + """Build an ssh command to execute a command on a remote node. -def BuildSSHCmd(hostname, user, command, batch=True, ask_key=False): - """Build an ssh string to execute a command on a remote node. + @param hostname: the target host, string + @param user: user to auth as + @param command: the command + @param batch: if true, ssh will run in batch mode with no prompting + @param ask_key: if true, ssh will run with + StrictHostKeyChecking=ask, so that we can connect to an + unknown host (not valid in batch mode) + @param use_cluster_key: whether to expect and use the + cluster-global SSH key + @param strict_host_check: whether to check the host's SSH key at all + @param private_key: use this private key instead of the default + @param quiet: whether to enable -q to ssh + + @return: the ssh call to run 'command' on the remote host. + + """ + argv = [constants.SSH] + argv.extend(self._BuildSshOptions(batch, ask_key, use_cluster_key, + strict_host_check, private_key, + quiet=quiet)) + if tty: + argv.extend(["-t", "-t"]) + + argv.append("%s@%s" % (user, hostname)) + + # Insert variables for virtual nodes + argv.extend("export %s=%s;" % + (utils.ShellQuote(name), utils.ShellQuote(value)) + for (name, value) in + vcluster.EnvironmentForHost(hostname).items()) + + argv.append(command) + + return argv + + def Run(self, *args, **kwargs): + """Runs a command on a remote node. - Args: - hostname: the target host, string - user: user to auth as - command: the command - batch: if true, ssh will run in batch mode with no prompting - ask_key: if true, ssh will run with StrictHostKeyChecking=ask, so that - we can connect to an unknown host (not valid in batch mode) + This method has the same return value as `utils.RunCmd()`, which it + uses to launch ssh. - Returns: - The ssh call to run 'command' on the remote host. + Args: see SshRunner.BuildCmd. - """ - argv = ["ssh", "-q"] - argv.extend(KNOWN_HOSTS_OPTS) - if batch: - # if we are in batch mode, we can't ask the key - if ask_key: - raise errors.ProgrammerError("SSH call requested conflicting options") - argv.extend(BATCH_MODE_OPTS) - elif ask_key: - argv.extend(ASK_KEY_OPTS) - argv.extend(["%s@%s" % (user, hostname), command]) - return argv - - -def SSHCall(hostname, user, command, batch=True, ask_key=False): - """Execute a command on a remote node. - - This method has the same return value as `utils.RunCmd()`, which it - uses to launch ssh. - - Args: - hostname: the target host, string - user: user to auth as - command: the command - batch: if true, ssh will run in batch mode with no prompting - ask_key: if true, ssh will run with StrictHostKeyChecking=ask, so that - we can connect to an unknown host (not valid in batch mode) - - Returns: - `utils.RunResult` as for `utils.RunCmd()` + @rtype: L{utils.process.RunResult} + @return: the result as from L{utils.process.RunCmd()} - """ - return utils.RunCmd(BuildSSHCmd(hostname, user, command, batch=batch, ask_key=ask_key)) + """ + return utils.RunCmd(self.BuildCmd(*args, **kwargs)) + def CopyFileToNode(self, node, filename): + """Copy a file to another node with scp. -def CopyFileToNode(node, filename): - """Copy a file to another node with scp. + @param node: node in the cluster + @param filename: absolute pathname of a local file - Args: - node: node in the cluster - filename: absolute pathname of a local file + @rtype: boolean + @return: the success of the operation - Returns: - success: True/False + """ + if not os.path.isabs(filename): + logging.error("File %s must be an absolute path", filename) + return False - """ - if not os.path.isfile(filename): - logger.Error("file %s does not exist" % (filename)) - return False + if not os.path.isfile(filename): + logging.error("File %s does not exist", filename) + return False - if not os.path.isabs(filename): - logger.Error("file %s must be an absolute path" % (filename)) - return False + command = [constants.SCP, "-p"] + command.extend(self._BuildSshOptions(True, False, True, True)) + command.append(filename) + if netutils.IP6Address.IsValid(node): + node = netutils.FormatAddress((node, None)) - command = ["scp", "-q", "-p"] - command.extend(KNOWN_HOSTS_OPTS) - command.extend(BATCH_MODE_OPTS) - command.append(filename) - command.append("%s:%s" % (node, filename)) + command.append("%s:%s" % (node, vcluster.ExchangeNodeRoot(node, filename))) - result = utils.RunCmd(command) + result = utils.RunCmd(command) - if result.failed: - logger.Error("copy to node %s failed (%s) error %s," - " command was %s" % - (node, result.fail_reason, result.output, result.cmd)) + if result.failed: + logging.error("Copy to node %s failed (%s) error '%s'," + " command was '%s'", + node, result.fail_reason, result.output, result.cmd) - return not result.failed + return not result.failed + def VerifyNodeHostname(self, node): + """Verify hostname consistency via SSH. -def VerifyNodeHostname(node): - """Verify hostname consistency via SSH. + This functions connects via ssh to a node and compares the hostname + reported by the node to the name with have (the one that we + connected to). + This is used to detect problems in ssh known_hosts files + (conflicting known hosts) and inconsistencies between dns/hosts + entries and local machine names - This functions connects via ssh to a node and compares the hostname - reported by the node to the name with have (the one that we - connected to). + @param node: nodename of a host to check; can be short or + full qualified hostname - This is used to detect problems in ssh known_hosts files - (conflicting known hosts) and incosistencies between dns/hosts - entries and local machine names + @return: (success, detail), where: + - success: True/False + - detail: string with details - Args: - node: nodename of a host to check. can be short or full qualified hostname + """ + cmd = ("if test -z \"$GANETI_HOSTNAME\"; then" + " hostname --fqdn;" + "else" + " echo \"$GANETI_HOSTNAME\";" + "fi") + retval = self.Run(node, constants.SSH_LOGIN_USER, cmd, quiet=False) - Returns: - (success, detail) - where - success: True/False - detail: String with details + if retval.failed: + msg = "ssh problem" + output = retval.output + if output: + msg += ": %s" % output + else: + msg += ": %s (no output)" % retval.fail_reason + logging.error("Command %s failed: %s", retval.cmd, msg) + return False, msg - """ - retval = SSHCall(node, 'root', 'hostname') + remotehostname = retval.stdout.strip() + + if not remotehostname or remotehostname != node: + if node.startswith(remotehostname + "."): + msg = "hostname not FQDN" + else: + msg = "hostname mismatch" + return False, ("%s: expected %s but got %s" % + (msg, node, remotehostname)) - if retval.failed: - msg = "ssh problem" - output = retval.output - if output: - msg += ": %s" % output - return False, msg + return True, "host matches" - remotehostname = retval.stdout.strip() - if not remotehostname or remotehostname != node: - return False, "hostname mismatch, got %s" % remotehostname +def WriteKnownHostsFile(cfg, file_name): + """Writes the cluster-wide equally known_hosts file. - return True, "host matches" + """ + utils.WriteFile(file_name, mode=0600, + data="%s ssh-rsa %s\n" % (cfg.GetClusterName(), + cfg.GetHostKey()))