/brz/remove-bazaar

# Copyright (C) 2005, 2006, 2007, 2009, 2011, 2012, 2013, 2016 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 breezy.lazy_import import lazy_import

lazy_import(globals(), """

import errno

import subprocess

from breezy import (

    config,

    trace,

    ui,

    )

from breezy.i18n import (

    gettext,

    ngettext,

    )

""")

from . import (

    errors,

    )

from .sixish import (

    BytesIO,

    )

#verification results

SIGNATURE_VALID = 0

SIGNATURE_KEY_MISSING = 1

SIGNATURE_NOT_VALID = 2

SIGNATURE_NOT_SIGNED = 3

SIGNATURE_EXPIRED = 4

class GpgNotInstalled(errors.DependencyNotPresent):

    _fmt = 'python-gpg is not installed, it is needed to verify signatures'

    def __init__(self, error):

        errors.DependencyNotPresent.__init__(self, 'gpg', error)

class SigningFailed(errors.BzrError):

    _fmt = 'Failed to GPG sign data: "%(error)s"'

    def __init__(self, error):

        errors.BzrError.__init__(self, error=error)

class SignatureVerificationFailed(errors.BzrError):

    _fmt = 'Failed to verify GPG signature data with error "%(error)s"'

    def __init__(self, error):

        errors.BzrError.__init__(self, error=error)

def bulk_verify_signatures(repository, revids, strategy,

        process_events_callback=None):

    """Do verifications on a set of revisions

    :param repository: repository object

    :param revids: list of revision ids to verify

    :param strategy: GPG strategy to use

    :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

    total = len(revids)

    with ui.ui_factory.nested_progress_bar() as pb:

        for i, (rev_id, verification_result, uid) in enumerate(

                repository.verify_revision_signatures(

                    revids, strategy)):

            pb.update("verifying signatures", i, total)

            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)

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 SigningFailed('Signing is disabled.')

    def verify(self, content, testament):

        raise 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 _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 ~/.brz.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 gpg

            self.context = gpg.Context()

        except ImportError as error:

            pass # can't use verify()

        self.context.signers = self._get_signing_keys()

    def _get_signing_keys(self):

        import gpg

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

        if keyname:

            try:

                return [self.context.get_key(keyname)]

            except gpg.errors.KeyNotFound:

                pass

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

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

            # use the user email address

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

        possible_keys = self.context.keylist(keyname, secret=True)

        try:

            return [possible_keys.next()]

        except StopIteration:

            return []

    @staticmethod

    def verify_signatures_available():

        """

        check if this strategy can verify signatures

        :return: boolean if this strategy can verify signatures

        """

        try:

            import gpg

            return True

        except ImportError as error:

            return False

    def sign(self, content):

        import gpg

        if isinstance(content, unicode):

            raise errors.BzrBadParameterUnicode('content')

        plain_text = gpg.Data(content)

        try:

            output, result = self.context.sign(

                plain_text, mode=gpg.constants.sig.mode.CLEAR)

        except gpg.errors.GPGMEError as error:

            raise SigningFailed(str(error))

        return output

    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 gpg

        except ImportError as error:

            raise errors.GpgNotInstalled(error)

        signature = gpg.Data(content)

        sink = gpg.Data()

        try:

            plain_output, result = self.context.verify(signature)

        except gpg.errors.BadSignatures as error:

            fingerprint = error.result.signatures[0].fpr

            if error.result.signatures[0].summary & gpg.constants.SIGSUM_KEY_EXPIRED:

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

                if expires > error.result.signatures[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

            # GPG does not know this key.

            # test_verify_unknown_key()

            if error.result.signatures[0].summary & gpg.constants.SIGSUM_KEY_MISSING:

                return SIGNATURE_KEY_MISSING, fingerprint[-8:]

            return SIGNATURE_NOT_VALID, None

        except gpg.errors.GPGMEError as error:

            raise SignatureVerificationFailed(error[2])

        # No result if input is invalid.

        # test_verify_invalid()

        if len(result.signatures) == 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.signatures[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:

            return SIGNATURE_NOT_VALID, None

        # Yay gpg set the valid bit.

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

        # trusted using gpg.

        if result.signatures[0].summary & gpg.constants.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.signatures[0].summary & gpg.constants.SIGSUM_RED:

            return SIGNATURE_NOT_VALID, None

        # 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.signatures[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.signatures[0].summary == 0 and self.acceptable_keys is None:

            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 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

        """

        patterns = None

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

        if acceptable_keys_config is not None:

            patterns = acceptable_keys_config

        if command_line_input is not None: # command line overrides config

            patterns = command_line_input.split(',')

        if patterns:

            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 valid_commits_message(count):

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

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

                                    count[SIGNATURE_VALID])

def unknown_key_message(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(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(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(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])

def verbose_expired_key_message(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 verbose_valid_message(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(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(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(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 list(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