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Diffstat (limited to 'cloudinit/ssh_util.py')
| -rw-r--r-- | cloudinit/ssh_util.py | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/cloudinit/ssh_util.py b/cloudinit/ssh_util.py new file mode 100644 index 00000000..a081fbe8 --- /dev/null +++ b/cloudinit/ssh_util.py @@ -0,0 +1,227 @@ +#!/usr/bin/python +# vi: ts=4 expandtab +# +# Copyright (C) 2012 Canonical Ltd. +# Copyright (C) 2012 Hewlett-Packard Development Company, L.P. +# +# Author: Scott Moser <scott.moser@canonical.com> +# Author: Juerg Hafliger <juerg.haefliger@hp.com> +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 3, as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +import os +import os.path +import cloudinit.util as util + + +class AuthKeyEntry(): + # lines are options, keytype, base64-encoded key, comment + # man page says the following which I did not understand: + # The options field is optional; its presence is determined by whether + # the line starts with a number or not (the options field never starts + # with a number) + options = None + keytype = None + base64 = None + comment = None + is_comment = False + line_in = "" + + def __init__(self, line, def_opt=None): + line = line.rstrip("\n\r") + self.line_in = line + if line.startswith("#") or line.strip() == "": + self.is_comment = True + else: + ent = line.strip() + toks = ent.split(None, 3) + if len(toks) == 1: + self.base64 = toks[0] + elif len(toks) == 2: + (self.base64, self.comment) = toks + elif len(toks) == 3: + (self.keytype, self.base64, self.comment) = toks + elif len(toks) == 4: + i = 0 + ent = line.strip() + quoted = False + # taken from auth_rsa_key_allowed in auth-rsa.c + try: + while (i < len(ent) and + ((quoted) or (ent[i] not in (" ", "\t")))): + curc = ent[i] + nextc = ent[i + 1] + if curc == "\\" and nextc == '"': + i = i + 1 + elif curc == '"': + quoted = not quoted + i = i + 1 + except IndexError: + self.is_comment = True + return + + try: + self.options = ent[0:i] + (self.keytype, self.base64, self.comment) = \ + ent[i + 1:].split(None, 3) + except ValueError: + # we did not understand this line + self.is_comment = True + + if self.options == None and def_opt: + self.options = def_opt + + return + + def debug(self): + print("line_in=%s\ncomment: %s\noptions=%s\nkeytype=%s\nbase64=%s\n" + "comment=%s\n" % (self.line_in, self.is_comment, self.options, + self.keytype, self.base64, self.comment)), + + def __repr__(self): + if self.is_comment: + return(self.line_in) + else: + toks = [] + for e in (self.options, self.keytype, self.base64, self.comment): + if e: + toks.append(e) + + return(' '.join(toks)) + + +def update_authorized_keys(fname, keys): + # keys is a list of AuthKeyEntries + # key_prefix is the prefix (options) to prepend + try: + fp = open(fname, "r") + lines = fp.readlines() # lines have carriage return + fp.close() + except IOError: + lines = [] + + ka_stats = {} # keys_added status + for k in keys: + ka_stats[k] = False + + to_add = [] + for key in keys: + to_add.append(key) + + for i in range(0, len(lines)): + ent = AuthKeyEntry(lines[i]) + for k in keys: + if k.base64 == ent.base64 and not k.is_comment: + ent = k + try: + to_add.remove(k) + except ValueError: + pass + lines[i] = str(ent) + + # now append any entries we did not match above + for key in to_add: + lines.append(str(key)) + + if len(lines) == 0: + return("") + else: + return('\n'.join(lines) + "\n") + + +def setup_user_keys(keys, user, key_prefix, log=None): + import pwd + saved_umask = os.umask(077) + + pwent = pwd.getpwnam(user) + + ssh_dir = '%s/.ssh' % pwent.pw_dir + if not os.path.exists(ssh_dir): + os.mkdir(ssh_dir) + os.chown(ssh_dir, pwent.pw_uid, pwent.pw_gid) + + try: + ssh_cfg = parse_ssh_config() + akeys = ssh_cfg.get("AuthorizedKeysFile", "%h/.ssh/authorized_keys") + akeys = akeys.replace("%h", pwent.pw_dir) + akeys = akeys.replace("%u", user) + if not akeys.startswith('/'): + akeys = os.path.join(pwent.pw_dir, akeys) + authorized_keys = akeys + except Exception: + authorized_keys = '%s/.ssh/authorized_keys' % pwent.pw_dir + if log: + util.logexc(log) + + key_entries = [] + for k in keys: + ke = AuthKeyEntry(k, def_opt=key_prefix) + key_entries.append(ke) + + content = update_authorized_keys(authorized_keys, key_entries) + util.write_file(authorized_keys, content, 0600) + + os.chown(authorized_keys, pwent.pw_uid, pwent.pw_gid) + util.restorecon_if_possible(ssh_dir, recursive=True) + + os.umask(saved_umask) + + +def parse_ssh_config(fname="/etc/ssh/sshd_config"): + ret = {} + fp = open(fname) + for l in fp.readlines(): + l = l.strip() + if not l or l.startswith("#"): + continue + key, val = l.split(None, 1) + ret[key] = val + fp.close() + return(ret) + +if __name__ == "__main__": + def main(): + import sys + # usage: orig_file, new_keys, [key_prefix] + # prints out merged, where 'new_keys' will trump old + ## example + ## ### begin auth_keys ### + # ssh-rsa AAAAB3NzaC1xxxxxxxxxV3csgm8cJn7UveKHkYjJp8= smoser-work + # ssh-rsa AAAAB3NzaC1xxxxxxxxxCmXp5Kt5/82cD/VN3NtHw== smoser@brickies + # ### end authorized_keys ### + # + # ### begin new_keys ### + # ssh-rsa nonmatch smoser@newhost + # ssh-rsa AAAAB3NzaC1xxxxxxxxxV3csgm8cJn7UveKHkYjJp8= new_comment + # ### end new_keys ### + # + # Then run as: + # program auth_keys new_keys \ + # 'no-port-forwarding,command=\"echo hi world;\"' + def_prefix = None + orig_key_file = sys.argv[1] + new_key_file = sys.argv[2] + if len(sys.argv) > 3: + def_prefix = sys.argv[3] + fp = open(new_key_file) + + newkeys = [] + for line in fp.readlines(): + newkeys.append(AuthKeyEntry(line, def_prefix)) + + fp.close() + print update_authorized_keys(orig_key_file, newkeys) + + main() + +# vi: ts=4 expandtab |