epicyon/pgp.py

__filename__ = "pgp.py"
__author__ = "Bob Mottram"
__license__ = "AGPL3+"
__version__ = "1.2.0"
__maintainer__ = "Bob Mottram"
__email__ = "bob@freedombone.net"
__status__ = "Production"

import os
import subprocess
from pathlib import Path
from person import getActorJson
from utils import containsPGPPublicKey
from utils import isPGPEncrypted
from utils import getFullDomain
from utils import getStatusNumber
from webfinger import webfingerHandle
from posts import getPersonBox
from auth import createBasicAuthHeader
from session import postJson


def getEmailAddress(actorJson: {}) -> str:
    """Returns the email address for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if '@' not in propertyValue['value']:
            continue
        if '.' not in propertyValue['value']:
            continue
        return propertyValue['value']
    return ''


def getPGPpubKey(actorJson: {}) -> str:
    """Returns PGP public key for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if not containsPGPPublicKey(propertyValue['value']):
            continue
        return propertyValue['value']
    return ''


def getPGPfingerprint(actorJson: {}) -> str:
    """Returns PGP fingerprint for the given actor
    """
    if not actorJson.get('attachment'):
        return ''
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue.get('value'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        if len(propertyValue['value']) < 10:
            continue
        return propertyValue['value']
    return ''


def setEmailAddress(actorJson: {}, emailAddress: str) -> None:
    """Sets the email address for the given actor
    """
    notEmailAddress = False
    if '@' not in emailAddress:
        notEmailAddress = True
    if '.' not in emailAddress:
        notEmailAddress = True
    if '<' in emailAddress:
        notEmailAddress = True
    if emailAddress.startswith('@'):
        notEmailAddress = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyFound)
    if notEmailAddress:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('email'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = emailAddress
        return

    newEmailAddress = {
        "name": "Email",
        "type": "PropertyValue",
        "value": emailAddress
    }
    actorJson['attachment'].append(newEmailAddress)


def setPGPpubKey(actorJson: {}, PGPpubKey: str) -> None:
    """Sets a PGP public key for the given actor
    """
    removeKey = False
    if not PGPpubKey:
        removeKey = True
    else:
        if not containsPGPPublicKey(PGPpubKey):
            removeKey = True
        if '<' in PGPpubKey:
            removeKey = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyValue)
    if removeKey:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('pgp'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = PGPpubKey
        return

    newPGPpubKey = {
        "name": "PGP",
        "type": "PropertyValue",
        "value": PGPpubKey
    }
    actorJson['attachment'].append(newPGPpubKey)


def setPGPfingerprint(actorJson: {}, fingerprint: str) -> None:
    """Sets a PGP fingerprint for the given actor
    """
    removeFingerprint = False
    if not fingerprint:
        removeFingerprint = True
    else:
        if len(fingerprint) < 10:
            removeFingerprint = True

    if not actorJson.get('attachment'):
        actorJson['attachment'] = []

    # remove any existing value
    propertyFound = None
    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        propertyFound = propertyValue
        break
    if propertyFound:
        actorJson['attachment'].remove(propertyValue)
    if removeFingerprint:
        return

    for propertyValue in actorJson['attachment']:
        if not propertyValue.get('name'):
            continue
        if not propertyValue.get('type'):
            continue
        if not propertyValue['name'].lower().startswith('openpgp'):
            continue
        if propertyValue['type'] != 'PropertyValue':
            continue
        propertyValue['value'] = fingerprint.strip()
        return

    newPGPfingerprint = {
        "name": "OpenPGP",
        "type": "PropertyValue",
        "value": fingerprint
    }
    actorJson['attachment'].append(newPGPfingerprint)


def extractPGPPublicKey(content: str) -> str:
    """Returns the PGP key from the given text
    """
    startBlock = '--BEGIN PGP PUBLIC KEY BLOCK--'
    endBlock = '--END PGP PUBLIC KEY BLOCK--'
    if startBlock not in content:
        return None
    if endBlock not in content:
        return None
    if '\n' not in content:
        return None
    linesList = content.split('\n')
    extracting = False
    publicKey = ''
    for line in linesList:
        if not extracting:
            if startBlock in line:
                extracting = True
        else:
            if endBlock in line:
                publicKey += line
                break
        if extracting:
            publicKey += line + '\n'
    return publicKey


def _pgpImportPubKey(recipientPubKey: str) -> str:
    """ Import the given public key
    """
    # do a dry run
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --dry-run --import 2> /dev/null'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if err:
        return None

    # this time for real
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --import 2> /dev/null'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if err:
        return None

    # get the key id
    cmdImportPubKey = \
        'echo "' + recipientPubKey + '" | gpg --show-keys'
    proc = subprocess.Popen([cmdImportPubKey],
                            stdout=subprocess.PIPE, shell=True)
    (importResult, err) = proc.communicate()
    if not importResult:
        return None
    importResult = importResult.decode('utf-8').split('\n')
    keyId = ''
    for line in importResult:
        if line.startswith('pub'):
            continue
        elif line.startswith('uid'):
            continue
        elif line.startswith('sub'):
            continue
        keyId = line.strip()
        break
    return keyId


def _pgpEncrypt(content: str, recipientPubKey: str) -> str:
    """ Encrypt using your default pgp key to the given recipient
    """
    keyId = _pgpImportPubKey(recipientPubKey)
    if not keyId:
        return None

    cmdEncrypt = \
        'echo "' + content + '" | gpg --encrypt --armor --recipient ' + \
        keyId + ' 2> /dev/null'
    proc = subprocess.Popen([cmdEncrypt],
                            stdout=subprocess.PIPE, shell=True)
    (encryptResult, err) = proc.communicate()
    if not encryptResult:
        return None
    encryptResult = encryptResult.decode('utf-8')
    if not isPGPEncrypted(encryptResult):
        return None
    return encryptResult


def _getPGPPublicKeyFromActor(handle: str, actorJson=None) -> str:
    """Searches tags on the actor to see if there is any PGP
    public key specified
    """
    if not actorJson:
        actorJson = getActorJson(handle, False, False, False, True)
    if not actorJson:
        return None
    if not actorJson.get('attachment'):
        return None
    if not isinstance(actorJson['attachment'], list):
        return None
    # search through the tags on the actor
    for tag in actorJson['attachment']:
        if not isinstance(tag, dict):
            continue
        if not tag.get('value'):
            continue
        if not isinstance(tag['value'], str):
            continue
        if containsPGPPublicKey(tag['value']):
            return tag['value']
    return None


def hasLocalPGPkey() -> bool:
    """Returns true if there is a local .gnupg directory
    """
    homeDir = str(Path.home())
    gpgDir = homeDir + '/.gnupg'
    if os.path.isdir(gpgDir):
        return True
    return False


def pgpEncryptToActor(content: str, toHandle: str) -> str:
    """PGP encrypt a message to the given actor or handle
    """
    # get the actor and extract the pgp public key from it
    recipientPubKey = _getPGPPublicKeyFromActor(toHandle)
    if not recipientPubKey:
        return None
    # encrypt using the recipient public key
    return _pgpEncrypt(content, recipientPubKey)


def pgpDecrypt(content: str, fromHandle: str) -> str:
    """ Encrypt using your default pgp key to the given recipient
    fromHandle can be a handle or actor url
    """
    if not isPGPEncrypted(content):
        return content

    # if the public key is also included within the message then import it
    if containsPGPPublicKey(content):
        pubKey = extractPGPPublicKey(content)
    else:
        pubKey = _getPGPPublicKeyFromActor(content, fromHandle)
    if pubKey:
        _pgpImportPubKey(pubKey)

    cmdDecrypt = \
        'echo "' + content + '" | gpg --decrypt --armor 2> /dev/null'
    proc = subprocess.Popen([cmdDecrypt],
                            stdout=subprocess.PIPE, shell=True)
    (decryptResult, err) = proc.communicate()
    if not decryptResult:
        return content
    decryptResult = decryptResult.decode('utf-8').strip()
    return decryptResult


def _pgpLocalPublicKeyId() -> str:
    """Gets the local pgp public key ID
    """
    cmdStr = \
        "gpgconf --list-options gpg | " + \
        "awk -F: '$1 == \"default-key\" {print $10}'"
    proc = subprocess.Popen([cmdStr],
                            stdout=subprocess.PIPE, shell=True)
    (result, err) = proc.communicate()
    if err:
        return None
    if not result:
        return None
    if len(result) < 5:
        return None
    return result.decode('utf-8').replace('"', '').strip()


def _pgpLocalPublicKey() -> str:
    """Gets the local pgp public key
    """
    keyId = _pgpLocalPublicKeyId()
    if not keyId:
        return None
    cmdStr = "gpg --armor --export " + keyId
    proc = subprocess.Popen([cmdStr],
                            stdout=subprocess.PIPE, shell=True)
    (result, err) = proc.communicate()
    if err:
        return None
    if not result:
        return None
    return extractPGPPublicKey(result.decode('utf-8'))


def pgpPublicKeyUpload(baseDir: str, session,
                       nickname: str, password: str,
                       domain: str, port: int,
                       httpPrefix: str,
                       cachedWebfingers: {}, personCache: {},
                       debug: bool, test: str) -> {}:
    if debug:
        print('pgpPublicKeyUpload')

    if not session:
        if debug:
            print('WARN: No session for pgpPublicKeyUpload')
        return None

    if not test:
        if debug:
            print('Getting PGP public key')
        PGPpubKey = _pgpLocalPublicKey()
        if not PGPpubKey:
            return None
        PGPpubKeyId = _pgpLocalPublicKeyId()
    else:
        if debug:
            print('Testing with PGP public key ' + test)
        PGPpubKey = test
        PGPpubKeyId = None

    domainFull = getFullDomain(domain, port)
    if debug:
        print('PGP test domain: ' + domainFull)

    handle = nickname + '@' + domainFull

    if debug:
        print('Getting actor for ' + handle)

    actorJson = getActorJson(handle, False, False, debug, True)
    if not actorJson:
        if debug:
            print('No actor returned for ' + handle)
        return None

    if debug:
        print('Actor for ' + handle + ' obtained')

    actor = httpPrefix + '://' + domainFull + '/users/' + nickname
    handle = actor.replace('/users/', '/@')

    # check that this looks like the correct actor
    if not actorJson.get('id'):
        if debug:
            print('Actor has no id')
        return None
    if not actorJson.get('url'):
        if debug:
            print('Actor has no url')
        return None
    if not actorJson.get('type'):
        if debug:
            print('Actor has no type')
        return None
    if actorJson['id'] != actor:
        if debug:
            print('Actor id is not ' + actor +
                  ' instead is ' + actorJson['id'])
        return None
    if actorJson['url'] != handle:
        if debug:
            print('Actor url is not ' + handle)
        return None
    if actorJson['type'] != 'Person':
        if debug:
            print('Actor type is not Person')
        return None

    # set the pgp details
    if PGPpubKeyId:
        setPGPfingerprint(actorJson, PGPpubKeyId)
    else:
        if debug:
            print('No PGP key Id. Continuing anyway.')

    if debug:
        print('Setting PGP key within ' + actor)
    setPGPpubKey(actorJson, PGPpubKey)

    # create an actor update
    statusNumber, published = getStatusNumber()
    actorUpdate = {
        '@context': 'https://www.w3.org/ns/activitystreams',
        'id': actor + '#updates/' + statusNumber,
        'type': 'Update',
        'actor': actor,
        'to': [actor],
        'cc': [],
        'object': actorJson
    }
    if debug:
        print('actor update is ' + str(actorUpdate))

    # lookup the inbox for the To handle
    wfRequest = \
        webfingerHandle(session, handle, httpPrefix, cachedWebfingers,
                        domain, __version__, debug)
    if not wfRequest:
        if debug:
            print('DEBUG: pgp actor update webfinger failed for ' +
                  handle)
        return None
    if not isinstance(wfRequest, dict):
        if debug:
            print('WARN: Webfinger for ' + handle +
                  ' did not return a dict. ' + str(wfRequest))
        return None

    postToBox = 'outbox'

    # get the actor inbox for the To handle
    (inboxUrl, pubKeyId, pubKey,
     fromPersonId, sharedInbox, avatarUrl,
     displayName) = getPersonBox(baseDir, session, wfRequest, personCache,
                                 __version__, httpPrefix, nickname,
                                 domain, postToBox, 52025)

    if not inboxUrl:
        if debug:
            print('DEBUG: No ' + postToBox + ' was found for ' + handle)
        return None
    if not fromPersonId:
        if debug:
            print('DEBUG: No actor was found for ' + handle)
        return None

    authHeader = createBasicAuthHeader(nickname, password)

    headers = {
        'host': domain,
        'Content-type': 'application/json',
        'Authorization': authHeader
    }
    quiet = not debug
    tries = 0
    while tries < 4:
        postResult = \
            postJson(session, actorUpdate, [], inboxUrl,
                     headers, 5, quiet)
        if postResult:
            break
        tries += 1

    if postResult is None:
        if debug:
            print('DEBUG: POST pgp actor update failed for c2s to ' +
                  inboxUrl)
        return None

    if debug:
        print('DEBUG: c2s POST pgp actor update success')

    return actorUpdate