source: trunk/host/credit-card/host.py @ 2246

Last change on this file since 2246 was 2246, checked in by ezyang, 9 years ago
Reintegrate Fedora 17 development branch into trunk.
File size: 6.5 KB
Line 
1import os
2import optparse
3import socket
4import tempfile
5import shutil
6import errno
7import csv
8
9import shell
10
11HOST = socket.gethostname()
12
13# XXX test server and wizard server
14
15# UIDs (sketchy):
16#   signup 102
17#   fedora-ds 103 (sketchy, not true for b-b)
18#   logview 501 (really sketchy, since it's in the dynamic range)
19
20# Works for passwd and group, but be careful! They're different things!
21def lookup(filename):
22    # Super-safe to assume and volume IDs (expensive to check)
23    r = {
24        'root': 0,
25        'sql': 537704221,
26    }
27    with open(filename, 'rb') as f:
28        reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)
29        for row in reader:
30            r[row[0]] = int(row[2])
31    return r
32
33# Format here assumes that we always chmod $USER:$USER ...
34# but note the latter refers to group...
35COMMON_CREDS = [
36    ('root', 0o600, 'root/.bashrc'),
37    ('root', 0o600, 'root/.screenrc'),
38    ('root', 0o600, 'root/.ssh/authorized_keys'),
39    ('root', 0o600, 'root/.ssh/authorized_keys2'),
40    ('root', 0o600, 'root/.vimrc'),
41    ('root', 0o600, 'root/.k5login'),
42    # punted /root/.ssh/known_hosts
43
44    # XXX user must be created in Kickstart
45    ('logview', 0o600, 'home/logview/.k5login'),
46    ]
47
48COMMON_PROD_CREDS = [ # important: no leading slashes!
49    ('root', 0o600, 'root/.ldapvirc'),
50    ('root', 0o600, 'etc/ssh/ssh_host_dsa_key'),
51    ('root', 0o600, 'etc/ssh/ssh_host_key'),
52    ('root', 0o600, 'etc/ssh/ssh_host_rsa_key'),
53    ('root', 0o600, 'etc/pki/tls/private/scripts-1024.key'),
54    ('root', 0o600, 'etc/pki/tls/private/scripts.key'),
55    ('root', 0o600, 'etc/whoisd-password'),
56    ('afsagent', 0o600, 'etc/daemon.keytab'),
57
58    ('root', 0o644, 'etc/ssh/ssh_host_dsa_key.pub'),
59    ('root', 0o644, 'etc/ssh/ssh_host_key.pub'),
60    ('root', 0o644, 'etc/ssh/ssh_host_rsa_key.pub'),
61
62    ('sql', 0o600, 'etc/sql-mit-edu.cfg.php'),
63    ('signup', 0o600, 'etc/signup-ldap-pw'),
64    ]
65
66MACHINE_PROD_CREDS = [
67    # XXX NEED TO CHECK THAT THESE ARE SENSIBLE
68    ('root', 0o600, 'etc/krb5.keytab'),
69    ('fedora-ds', 0o600, 'etc/dirsrv/keytab')
70    ]
71
72def drop_caches():
73    with open("/proc/sys/vm/drop_caches", 'w') as f:
74        f.write("1")
75
76def mkdir_p(path): # it's like mkdir -p
77    try:
78        os.makedirs(path)
79    except OSError as e:
80        if e.errno == errno.EEXIST:
81            pass
82        else: raise
83
84# XXX This code is kind of dangerous, because we are directly using the
85# kernel modules to manipulate possibly untrusted disk images.  This
86# means that if an attacker can corrupt the disk, and exploit a problem
87# in the kernel vfs driver, he can escalate a guest root exploit
88# to a host root exploit.  Ultimately we should use libguestfs
89# which makes this attack harder to pull off, but at the time of writing
90# squeeze didn't package libguestfs.
91#
92# We try to minimize attack surface by explicitly specifying the
93# expected filesystem type.
94class WithMount(object):
95    """Context for running code with an extra mountpoint."""
96    guest = None
97    types = None # comma separated, like the mount argument -t
98    mount = None
99    dev = None
100    def __init__(self, guest, types):
101        self.guest = guest
102        self.types = types
103    def __enter__(self):
104        drop_caches()
105        self.dev = "/dev/%s/%s-root" % (HOST, self.guest)
106
107        mapper_name = shell.eval("kpartx", "-l", self.dev).split()[0]
108        shell.call("kpartx", "-a", self.dev)
109        mapper = "/dev/mapper/%s" % mapper_name
110
111        # this is why bracketing functions and hanging lambdas are a good idea
112        try:
113            self.mount = tempfile.mkdtemp("-%s" % self.guest, 'vm-', '/mnt') # no trailing slash
114            try:
115                shell.call("mount", "--types", self.types, mapper, self.mount)
116            except:
117                os.rmdir(self.mount)
118                raise
119        except:
120            shell.call("kpartx", "-d", self.dev)
121            raise
122
123        return self.mount
124    def __exit__(self, _type, _value, _traceback):
125        shell.call("umount", self.mount)
126        os.rmdir(self.mount)
127        shell.call("kpartx", "-d", self.dev)
128        drop_caches()
129
130def main():
131    usage = """usage: %prog [push|pull|pull-common] GUEST"""
132
133    parser = optparse.OptionParser(usage)
134    # ext3 will probably supported for a while yet and a pretty
135    # reasonable thing to always try
136    parser.add_option('-t', '--types', dest="types", default="ext4,ext3",
137            help="filesystem type(s)")
138    parser.add_option('--creds-dir', dest="creds_dir", default="/root/creds",
139            help="directory to store/fetch credentials in")
140    options, args = parser.parse_args()
141
142    if not os.path.isdir(options.creds_dir):
143        raise Exception("/root/creds does not exist") # XXX STRING
144    # XXX check owned by root and appropriately chmodded
145
146    os.umask(0o077) # overly restrictive
147
148    if len(args) != 2:
149        parser.print_help()
150        raise Exception("Wrong number of arguments")
151
152    command = args[0]
153    guest   = args[1]
154
155    with WithMount(guest, options.types) as tmp_mount:
156        uid_lookup = lookup("%s/etc/passwd" % tmp_mount)
157        gid_lookup = lookup("%s/etc/group" % tmp_mount)
158        def push_files(files, type):
159            for (usergroup, perms, f) in files:
160                dest = "%s/%s" % (tmp_mount, f)
161                mkdir_p(os.path.dirname(dest)) # useful for .ssh
162                # assuming OK to overwrite
163                # XXX we could compare the files before doing anything...
164                shutil.copyfile("%s/%s/%s" % (options.creds_dir, type, f), dest)
165                try:
166                    os.chown(dest, uid_lookup[usergroup], gid_lookup[usergroup])
167                    os.chmod(dest, perms)
168                except:
169                    # never ever leave un-chowned files lying around
170                    os.unlink(dest)
171                    raise
172        def pull_files(files, type):
173            for (_, _, f) in files:
174                dest = "%s/%s/%s" % (options.creds_dir, type, f)
175                mkdir_p(os.path.dirname(dest))
176                # error if doesn't exist
177                shutil.copyfile("%s/%s" % (tmp_mount, f), dest)
178
179        if command == "push":
180            push_files(COMMON_CREDS, 'common')
181            push_files(COMMON_PROD_CREDS,  'common')
182            push_files(MACHINE_PROD_CREDS, 'machine/%s' % guest)
183        elif command == "pull":
184            pull_files(MACHINE_PROD_CREDS, 'machine/%s' % guest)
185        elif command == "pull-common":
186            pull_files(COMMON_CREDS, 'common')
187            pull_files(COMMON_PROD_CREDS,  'common')
188
189if __name__ == "__main__":
190    main()
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