~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005, 2011 Canonical Ltd

#   Authors: Robert Collins <robert.collins@canonical.com>

#

# 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

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# 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, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""GPG signing and checking logic."""

from __future__ import absolute_import

import os

import sys

from StringIO import StringIO

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

import errno

import subprocess

from bzrlib import (

    config,

    errors,

    trace,

    ui,

    )

from bzrlib.i18n import (

    gettext, 

    ngettext,

    )

""")

#verification results

SIGNATURE_VALID = 0

SIGNATURE_KEY_MISSING = 1

SIGNATURE_NOT_VALID = 2

SIGNATURE_NOT_SIGNED = 3

SIGNATURE_EXPIRED = 4

class DisabledGPGStrategy(object):

    """A GPG Strategy that makes everything fail."""

    @staticmethod

    def verify_signatures_available():

        return True

    def __init__(self, ignored):

        """Real strategies take a configuration."""

    def sign(self, content):

        raise errors.SigningFailed('Signing is disabled.')

    def verify(self, content, testament):

        raise errors.SignatureVerificationFailed('Signature verification is \

disabled.')

    def set_acceptable_keys(self, command_line_input):

        pass

class LoopbackGPGStrategy(object):

    """A GPG Strategy that acts like 'cat' - data is just passed through.

    Used in tests.

    """

    @staticmethod

    def verify_signatures_available():

        return True

    def __init__(self, ignored):

        """Real strategies take a configuration."""

    def sign(self, content):

        return ("-----BEGIN PSEUDO-SIGNED CONTENT-----\n" + content +

                "-----END PSEUDO-SIGNED CONTENT-----\n")

    def verify(self, content, testament):

        return SIGNATURE_VALID, None

    def set_acceptable_keys(self, command_line_input):

        if command_line_input is not None:

            patterns = command_line_input.split(",")

            self.acceptable_keys = []

            for pattern in patterns:

                if pattern == "unknown":

                    pass

                else:

                    self.acceptable_keys.append(pattern)

    def do_verifications(self, revisions, repository):

        count = {SIGNATURE_VALID: 0,

                 SIGNATURE_KEY_MISSING: 0,

                 SIGNATURE_NOT_VALID: 0,

                 SIGNATURE_NOT_SIGNED: 0,

                 SIGNATURE_EXPIRED: 0}

        result = []

        all_verifiable = True

        for rev_id in revisions:

            verification_result, uid =\

                repository.verify_revision_signature(rev_id,self)

            result.append([rev_id, verification_result, uid])

            count[verification_result] += 1

            if verification_result != SIGNATURE_VALID:

                all_verifiable = False

        return (count, result, all_verifiable)

    def valid_commits_message(self, count):

        return gettext(u"{0} commits with valid signatures").format(

                                        count[SIGNATURE_VALID])

    def unknown_key_message(self, count):

        return ngettext(u"{0} commit with unknown key",

                             u"{0} commits with unknown keys",

                             count[SIGNATURE_KEY_MISSING]).format(

                                        count[SIGNATURE_KEY_MISSING])

    def commit_not_valid_message(self, count):

        return ngettext(u"{0} commit not valid",

                             u"{0} commits not valid",

                             count[SIGNATURE_NOT_VALID]).format(

                                            count[SIGNATURE_NOT_VALID])

    def commit_not_signed_message(self, count):

        return ngettext(u"{0} commit not signed",

                             u"{0} commits not signed",

                             count[SIGNATURE_NOT_SIGNED]).format(

                                        count[SIGNATURE_NOT_SIGNED])

    def expired_commit_message(self, count):

        return ngettext(u"{0} commit with key now expired",

                        u"{0} commits with key now expired",

                        count[SIGNATURE_EXPIRED]).format(

                                        count[SIGNATURE_EXPIRED])

def _set_gpg_tty():

    tty = os.environ.get('TTY')

    if tty is not None:

        os.environ['GPG_TTY'] = tty

        trace.mutter('setting GPG_TTY=%s', tty)

    else:

        # This is not quite worthy of a warning, because some people

        # don't need GPG_TTY to be set. But it is worthy of a big mark

        # in ~/.bzr.log, so that people can debug it if it happens to them

        trace.mutter('** Env var TTY empty, cannot set GPG_TTY.'

                     '  Is TTY exported?')

class GPGStrategy(object):

    """GPG Signing and checking facilities."""

    acceptable_keys = None

    def __init__(self, config_stack):

        self._config_stack = config_stack

        try:

            import gpgme

            self.context = gpgme.Context()

        except ImportError, error:

            pass # can't use verify()

    @staticmethod

    def verify_signatures_available():

        """

        check if this strategy can verify signatures

        :return: boolean if this strategy can verify signatures

        """

        try:

            import gpgme

            return True

        except ImportError, error:

            return False

    def _command_line(self):

        key = self._config_stack.get('gpg_signing_key')

        if key is None or key == 'default':

            # 'default' or not setting gpg_signing_key at all means we should

            # use the user email address

            key = config.extract_email_address(self._config_stack.get('email'))

        return [self._config_stack.get('gpg_signing_command'), '--clearsign',

                '-u', key]

    def sign(self, content):

        if isinstance(content, unicode):

            raise errors.BzrBadParameterUnicode('content')

        ui.ui_factory.clear_term()

        preexec_fn = _set_gpg_tty

        if sys.platform == 'win32':

            # Win32 doesn't support preexec_fn, but wouldn't support TTY anyway.

            preexec_fn = None

        try:

            process = subprocess.Popen(self._command_line(),

                                       stdin=subprocess.PIPE,

                                       stdout=subprocess.PIPE,

                                       preexec_fn=preexec_fn)

            try:

                result = process.communicate(content)[0]

                if process.returncode is None:

                    process.wait()

                if process.returncode != 0:

                    raise errors.SigningFailed(self._command_line())

                return result

            except OSError, e:

                if e.errno == errno.EPIPE:

                    raise errors.SigningFailed(self._command_line())

                else:

                    raise

        except ValueError:

            # bad subprocess parameters, should never happen.

            raise

        except OSError, e:

            if e.errno == errno.ENOENT:

                # gpg is not installed

                raise errors.SigningFailed(self._command_line())

            else:

                raise

    def verify(self, content, testament):

        """Check content has a valid signature.

        :param content: the commit signature

        :param testament: the valid testament string for the commit

        :return: SIGNATURE_VALID or a failed SIGNATURE_ value, key uid if valid

        """

        try:

            import gpgme

        except ImportError, error:

            raise errors.GpgmeNotInstalled(error)

        signature = StringIO(content)

        plain_output = StringIO()

        try:

            result = self.context.verify(signature, None, plain_output)

        except gpgme.GpgmeError,error:

            raise errors.SignatureVerificationFailed(error[2])

        # No result if input is invalid.

        # test_verify_invalid()

        if len(result) == 0:

            return SIGNATURE_NOT_VALID, None

        # User has specified a list of acceptable keys, check our result is in

        # it.  test_verify_unacceptable_key()

        fingerprint = result[0].fpr

        if self.acceptable_keys is not None:

            if not fingerprint in self.acceptable_keys:

                return SIGNATURE_KEY_MISSING, fingerprint[-8:]

        # Check the signature actually matches the testament.

        # test_verify_bad_testament()

        if testament != plain_output.getvalue():

            return SIGNATURE_NOT_VALID, None

        # Yay gpgme set the valid bit.

        # Can't write a test for this one as you can't set a key to be

        # trusted using gpgme.

        if result[0].summary & gpgme.SIGSUM_VALID:

            key = self.context.get_key(fingerprint)

            name = key.uids[0].name

            email = key.uids[0].email

            return SIGNATURE_VALID, name + " <" + email + ">"

        # Sigsum_red indicates a problem, unfortunatly I have not been able

        # to write any tests which actually set this.

        if result[0].summary & gpgme.SIGSUM_RED:

            return SIGNATURE_NOT_VALID, None

        # GPG does not know this key.

        # test_verify_unknown_key()

        if result[0].summary & gpgme.SIGSUM_KEY_MISSING:

            return SIGNATURE_KEY_MISSING, fingerprint[-8:]

        # Summary isn't set if sig is valid but key is untrusted but if user

        # has explicity set the key as acceptable we can validate it.

        if result[0].summary == 0 and self.acceptable_keys is not None:

            if fingerprint in self.acceptable_keys:

                # test_verify_untrusted_but_accepted()

                return SIGNATURE_VALID, None

        # test_verify_valid_but_untrusted()

        if result[0].summary == 0 and self.acceptable_keys is None:

            return SIGNATURE_NOT_VALID, None

        if result[0].summary & gpgme.SIGSUM_KEY_EXPIRED:

            expires = self.context.get_key(result[0].fpr).subkeys[0].expires

            if expires > result[0].timestamp:

                # The expired key was not expired at time of signing.

                # test_verify_expired_but_valid()

                return SIGNATURE_EXPIRED, fingerprint[-8:]

            else:

                # I can't work out how to create a test where the signature

                # was expired at the time of signing.

                return SIGNATURE_NOT_VALID, None

        # A signature from a revoked key gets this.

        # test_verify_revoked_signature()

        if result[0].summary & gpgme.SIGSUM_SYS_ERROR:

            return SIGNATURE_NOT_VALID, None

        # Other error types such as revoked keys should (I think) be caught by

        # SIGSUM_RED so anything else means something is buggy.

        raise errors.SignatureVerificationFailed("Unknown GnuPG key "\

                                                 "verification result")

    def set_acceptable_keys(self, command_line_input):

        """Set the acceptable keys for verifying with this GPGStrategy.

        :param command_line_input: comma separated list of patterns from

                                command line

        :return: nothing

        """

        key_patterns = None

        acceptable_keys_config = self._config_stack.get('acceptable_keys')

        try:

            if isinstance(acceptable_keys_config, unicode):

                acceptable_keys_config = str(acceptable_keys_config)

        except UnicodeEncodeError:

            # gpg Context.keylist(pattern) does not like unicode

            raise errors.BzrCommandError(

                gettext('Only ASCII permitted in option names'))

        if acceptable_keys_config is not None:

            key_patterns = acceptable_keys_config

        if command_line_input is not None: # command line overrides config

            key_patterns = command_line_input

        if key_patterns is not None:

            patterns = key_patterns.split(",")

            self.acceptable_keys = []

            for pattern in patterns:

                result = self.context.keylist(pattern)

                found_key = False

                for key in result:

                    found_key = True

                    self.acceptable_keys.append(key.subkeys[0].fpr)

                    trace.mutter("Added acceptable key: " + key.subkeys[0].fpr)

                if not found_key:

                    trace.note(gettext(

                            "No GnuPG key results for pattern: {0}"

                                ).format(pattern))

    def do_verifications(self, revisions, repository,

                            process_events_callback=None):

        """do verifications on a set of revisions

        :param revisions: list of revision ids to verify

        :param repository: repository object

        :param process_events_callback: method to call for GUI frontends that

                                                want to keep their UI refreshed

        :return: count dictionary of results of each type,

                 result list for each revision,

                 boolean True if all results are verified successfully

        """

        count = {SIGNATURE_VALID: 0,

                 SIGNATURE_KEY_MISSING: 0,

                 SIGNATURE_NOT_VALID: 0,

                 SIGNATURE_NOT_SIGNED: 0,

                 SIGNATURE_EXPIRED: 0}

        result = []

        all_verifiable = True

        for rev_id in revisions:

            verification_result, uid =\

                repository.verify_revision_signature(rev_id, self)

            result.append([rev_id, verification_result, uid])

            count[verification_result] += 1

            if verification_result != SIGNATURE_VALID:

                all_verifiable = False

            if process_events_callback is not None:

                process_events_callback()

        return (count, result, all_verifiable)

    def verbose_valid_message(self, result):

        """takes a verify result and returns list of signed commits strings"""

        signers = {}

        for rev_id, validity, uid in result:

            if validity == SIGNATURE_VALID:

                signers.setdefault(uid, 0)

                signers[uid] += 1

        result = []

        for uid, number in signers.items():

             result.append( ngettext(u"{0} signed {1} commit",

                             u"{0} signed {1} commits",

                             number).format(uid, number) )

        return result

    def verbose_not_valid_message(self, result, repo):

        """takes a verify result and returns list of not valid commit info"""

        signers = {}

        for rev_id, validity, empty in result:

            if validity == SIGNATURE_NOT_VALID:

                revision = repo.get_revision(rev_id)

                authors = ', '.join(revision.get_apparent_authors())

                signers.setdefault(authors, 0)

                signers[authors] += 1

        result = []

        for authors, number in signers.items():

            result.append( ngettext(u"{0} commit by author {1}",

                                 u"{0} commits by author {1}",

                                 number).format(number, authors) )

        return result

    def verbose_not_signed_message(self, result, repo):

        """takes a verify result and returns list of not signed commit info"""

        signers = {}

        for rev_id, validity, empty in result:

            if validity == SIGNATURE_NOT_SIGNED:

                revision = repo.get_revision(rev_id)

                authors = ', '.join(revision.get_apparent_authors())

                signers.setdefault(authors, 0)

                signers[authors] += 1

        result = []

        for authors, number in signers.items():

            result.append( ngettext(u"{0} commit by author {1}",

                                 u"{0} commits by author {1}",

                                 number).format(number, authors) )

        return result

    def verbose_missing_key_message(self, result):

        """takes a verify result and returns list of missing key info"""

        signers = {}

        for rev_id, validity, fingerprint in result:

            if validity == SIGNATURE_KEY_MISSING:

                signers.setdefault(fingerprint, 0)

                signers[fingerprint] += 1

        result = []

        for fingerprint, number in signers.items():

            result.append( ngettext(u"Unknown key {0} signed {1} commit",

                                 u"Unknown key {0} signed {1} commits",

                                 number).format(fingerprint, number) )

        return result

    def verbose_expired_key_message(self, result, repo):

        """takes a verify result and returns list of expired key info"""

        signers = {}

        fingerprint_to_authors = {}

        for rev_id, validity, fingerprint in result:

            if validity == SIGNATURE_EXPIRED:

                revision = repo.get_revision(rev_id)

                authors = ', '.join(revision.get_apparent_authors())

                signers.setdefault(fingerprint, 0)

                signers[fingerprint] += 1

                fingerprint_to_authors[fingerprint] = authors

        result = []

        for fingerprint, number in signers.items():

            result.append(

                ngettext(u"{0} commit by author {1} with key {2} now expired",

                         u"{0} commits by author {1} with key {2} now expired",

                         number).format(

                    number, fingerprint_to_authors[fingerprint], fingerprint) )

        return result

    def valid_commits_message(self, count):

        """returns message for number of commits"""

        return gettext(u"{0} commits with valid signatures").format(

                                        count[SIGNATURE_VALID])

    def unknown_key_message(self, count):

        """returns message for number of commits"""

        return ngettext(u"{0} commit with unknown key",

                        u"{0} commits with unknown keys",

                        count[SIGNATURE_KEY_MISSING]).format(

                                        count[SIGNATURE_KEY_MISSING])

    def commit_not_valid_message(self, count):

        """returns message for number of commits"""

        return ngettext(u"{0} commit not valid",

                        u"{0} commits not valid",

                        count[SIGNATURE_NOT_VALID]).format(

                                            count[SIGNATURE_NOT_VALID])

    def commit_not_signed_message(self, count):

        """returns message for number of commits"""

        return ngettext(u"{0} commit not signed",

                        u"{0} commits not signed",

                        count[SIGNATURE_NOT_SIGNED]).format(

                                        count[SIGNATURE_NOT_SIGNED])

    def expired_commit_message(self, count):

        """returns message for number of commits"""

        return ngettext(u"{0} commit with key now expired",

                        u"{0} commits with key now expired",

                        count[SIGNATURE_EXPIRED]).format(

                                    count[SIGNATURE_EXPIRED])