Source code for duplicity.gpginterface

# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4; encoding:utf-8 -*-
"""Interface to GNU Privacy Guard (GnuPG)

!!! This was renamed to
    Please refer to duplicity's README for the reason. !!!

gpginterface is a Python module to interface with GnuPG which based on
GnuPGInterface by Frank J. Tobin.
It concentrates on interacting with GnuPG via filehandles,
providing access to control GnuPG via versatile and extensible means.

This module is based on GnuPG::Interface, a Perl module by the same author.

Normally, using this module will involve creating a
GnuPG object, setting some options in it's 'options' data member
(which is of type Options), creating some pipes
to talk with GnuPG, and then calling the run() method, which will
connect those pipes to the GnuPG process. run() returns a
Process object, which contains the filehandles to talk to GnuPG with.

Example code:

>>> import gpginterface
>>> plaintext  = b"Three blind mice"
>>> passphrase = "This is the passphrase"
>>> gnupg = gpginterface.GnuPG()
>>> gnupg.options.armor = 1
>>> gnupg.options.meta_interactive = 0
>>> gnupg.options.extra_args.append('--no-secmem-warning')
>>> # Normally we might specify something in
>>> # gnupg.options.recipients, like
>>> # gnupg.options.recipients = [ '0xABCD1234', '' ]
>>> # but since we're doing symmetric-only encryption, it's not needed.
>>> # If you are doing standard, public-key encryption, using
>>> # --encrypt, you will need to specify recipients before
>>> # calling
>>> # First we'll encrypt the test_text input symmetrically
>>> p1 =['--symmetric'],
...                create_fhs=['stdin', 'stdout', 'passphrase'])
>>> ret = p1.handles['passphrase'].write(passphrase)
>>> p1.handles['passphrase'].close()
>>> ret = p1.handles['stdin'].write(plaintext)
>>> p1.handles['stdin'].close()
>>> ciphertext = p1.handles['stdout'].read()
>>> p1.handles['stdout'].close()
>>> # process cleanup
>>> p1.wait()
>>> # Now we'll decrypt what we just encrypted it,
>>> # using the convience method to get the
>>> # passphrase to GnuPG
>>> gnupg.passphrase = passphrase
>>> p2 =['--decrypt'], create_fhs=['stdin', 'stdout'])
>>> ret = p2.handles['stdin'].write(ciphertext)
>>> p2.handles['stdin'].close()
>>> decrypted_plaintext = p2.handles['stdout'].read()
>>> p2.handles['stdout'].close()
>>> # process cleanup
>>> p2.wait()
>>> # Our decrypted plaintext:
>>> decrypted_plaintext
b'Three blind mice'
>>> # ...and see it's the same as what we orignally encrypted
>>> assert decrypted_plaintext == plaintext, \
          "GnuPG decrypted output does not match original input"
>>> ##################################################
>>> # Now let's trying using run()'s attach_fhs parameter
>>> # we're assuming we're running on a unix...
>>> infp = open('/etc/manpaths', 'rb')
>>> p1 =['--symmetric'], create_fhs=['stdout'],
...                                 attach_fhs={'stdin': infp})
>>> # GnuPG will read the stdin from /etc/motd
>>> ciphertext = p1.handles['stdout'].read()
>>> # process cleanup
>>> p1.wait()
>>> # Now let's run the output through GnuPG
>>> # We'll write the output to a temporary file,
>>> import tempfile
>>> temp = tempfile.TemporaryFile()
>>> p2 =['--decrypt'], create_fhs=['stdin'],
...                               attach_fhs={'stdout': temp})
>>> # give GnuPG our encrypted stuff from the first run
>>> ret = p2.handles['stdin'].write(ciphertext)
>>> p2.handles['stdin'].close()
>>> # process cleanup
>>> p2.wait()
>>> # rewind the tempfile and see what GnuPG gave us
>>> ret =
>>> decrypted_plaintext =
>>> # compare what GnuPG decrypted with our original input
>>> ret =
>>> input_data =
>>> assert decrypted_plaintext == input_data, \
           "GnuPG decrypted output does not match original input"

To do things like public-key encryption, simply pass do something

gnupg.passphrase = 'My passphrase'
gnupg.options.recipients = [ '' ] ['--sign', '--encrypt'], create_fhs=..., attach_fhs=...)

Here is an example of subclassing gpginterface.GnuPG,
so that it has an encrypt_string() method that returns

>>> import gpginterface
>>> class MyGnuPG(gpginterface.GnuPG):
...     def __init__(self):
...         super().__init__()
...         self.setup_my_options()
...     def setup_my_options(self):
...         self.options.armor = 1
...         self.options.meta_interactive = 0
...         self.options.extra_args.append('--no-secmem-warning')
...     def encrypt_string(self, string, recipients):
...        gnupg.options.recipients = recipients   # a list!
...        proc =['--encrypt'], create_fhs=['stdin', 'stdout'])
...        proc.handles['stdin'].write(string)
...        proc.handles['stdin'].close()
...        output = proc.handles['stdout'].read()
...        proc.handles['stdout'].close()
...        proc.wait()
...        return output
>>> gnupg = MyGnuPG()
>>> ciphertext = gnupg.encrypt_string(b"The secret", ['E477C232'])
>>> # just a small sanity test here for doctest
>>> import types
>>> assert isinstance(ciphertext, bytes), \
           "What GnuPG gave back is not bytes!"

Here is an example of generating a key:
>>> import gpginterface
>>> gnupg = gpginterface.GnuPG()
>>> gnupg.options.meta_interactive = 0
>>> # We will be creative and use the logger filehandle to capture
>>> # what GnuPG says this time, instead stderr; no stdout to listen to,
>>> # but we capture logger to surpress the dry-run command.
>>> # We also have to capture stdout since otherwise doctest complains;
>>> # Normally you can let stdout through when generating a key.
>>> proc =['--gen-key'], create_fhs=['stdin', 'stdout',
...                                             'logger'])
>>> ret = proc.handles['stdin'].write(b'''Key-Type: DSA
... Key-Length: 1024
... # We are only testing syntax this time, so dry-run
... %dry-run
... Subkey-Type: ELG-E
... Subkey-Length: 1024
... Name-Real: Joe Tester
... Name-Comment: with stupid passphrase
... Name-Email:
... Expire-Date: 2y
... Passphrase: abc
... %pubring
... %secring foo.sec
... ''')
>>> proc.handles['stdin'].close()
>>> report = proc.handles['logger'].read()
>>> proc.handles['logger'].close()
>>> proc.wait()


Copyright (C) 2001  Frank J. Tobin,


This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
or see

import fcntl
import os
import sys

from duplicity import log

import threading

__author__ = "Frank J. Tobin,"
__version__ = "0.3.2"
__revision__ = "$Id:,v 1.6 2009/06/06 17:35:19 loafman Exp $"

# "standard" filehandles attached to processes
_stds = ["stdin", "stdout", "stderr"]

# the permissions each type of fh needs to be opened with
_fd_modes = {
    "stdin": "wb",
    "stdout": "rb",
    "stderr": "r",
    "passphrase": "w",
    "command": "w",
    "logger": "r",
    "status": "r",

# correlation between handle names and the arguments we'll pass
_fd_options = {
    "passphrase": "--passphrase-fd",
    "logger": "--logger-fd",
    "status": "--status-fd",
    "command": "--command-fd",

[docs]class GnuPG(object): """Class instances represent GnuPG. Instance attributes of a GnuPG object are: * call -- string to call GnuPG with. Defaults to "gpg" * passphrase -- Since it is a common operation to pass in a passphrase to GnuPG, and working with the passphrase filehandle mechanism directly can be mundane, if set, the passphrase attribute works in a special manner. If the passphrase attribute is set, and no passphrase file object is sent in to run(), then GnuPG instnace will take care of sending the passphrase to GnuPG, the executable instead of having the user sent it in manually. * options -- Object of type gpginterface.Options. Attribute-setting in options determines the command-line options used when calling GnuPG. """
[docs] def __init__(self): = "gpg" self.passphrase = None self.options = Options()
[docs] def run(self, gnupg_commands, args=None, create_fhs=None, attach_fhs=None): """Calls GnuPG with the list of string commands gnupg_commands, complete with prefixing dashes. For example, gnupg_commands could be '["--sign", "--encrypt"]' Returns a gpginterface.Process object. args is an optional list of GnuPG command arguments (not options), such as keyID's to export, filenames to process, etc. create_fhs is an optional list of GnuPG filehandle names that will be set as keys of the returned Process object's 'handles' attribute. The generated filehandles can be used to communicate with GnuPG via standard input, standard output, the status-fd, passphrase-fd, etc. Valid GnuPG filehandle names are: * stdin * stdout * stderr * status * passphase * command * logger The purpose of each filehandle is described in the GnuPG documentation. attach_fhs is an optional dictionary with GnuPG filehandle names mapping to opened files. GnuPG will read or write to the file accordingly. For example, if 'my_file' is an opened file and 'attach_fhs[stdin] is my_file', then GnuPG will read its standard input from my_file. This is useful if you want GnuPG to read/write to/from an existing file. For instance: f = open("encrypted.gpg")["--decrypt"], attach_fhs={'stdin': f}) Using attach_fhs also helps avoid system buffering issues that can arise when using create_fhs, which can cause the process to deadlock. If not mentioned in create_fhs or attach_fhs, GnuPG filehandles which are a std* (stdin, stdout, stderr) are defaulted to the running process' version of handle. Otherwise, that type of handle is simply not used when calling GnuPG. For example, if you do not care about getting data from GnuPG's status filehandle, simply do not specify it. run() returns a Process() object which has a 'handles' which is a dictionary mapping from the handle name (such as 'stdin' or 'stdout') to the respective newly-created FileObject connected to the running GnuPG process. For instance, if the call was process =["--decrypt"], stdin=1) after run returns 'process.handles["stdin"]' is a FileObject connected to GnuPG's standard input, and can be written to. """ if args is None: args = [] if create_fhs is None: create_fhs = [] if attach_fhs is None: attach_fhs = {} for std in _stds: if std not in attach_fhs and std not in create_fhs: attach_fhs.setdefault(std, getattr(sys, std)) handle_passphrase = 0 if self.passphrase is not None and "passphrase" not in attach_fhs and "passphrase" not in create_fhs: handle_passphrase = 1 create_fhs.append("passphrase") process = self._attach_fork_exec(gnupg_commands, args, create_fhs, attach_fhs) if handle_passphrase: passphrase_fh = process.handles["passphrase"] passphrase_fh.write(self.passphrase) passphrase_fh.close() del process.handles["passphrase"] return process
[docs] def _attach_fork_exec(self, gnupg_commands, args, create_fhs, attach_fhs): """This is like run(), but without the passphrase-helping (note that run() calls this).""" process = Process() for fh_name in create_fhs + list(attach_fhs.keys()): if fh_name not in _fd_modes: raise KeyError(f"unrecognized filehandle name '{fh_name}'; " f"must be one of {list(_fd_modes.keys())}") for fh_name in create_fhs: # make sure the user doesn't specify a filehandle # to be created *and* attached if fh_name in attach_fhs: raise ValueError(f"cannot have filehandle '{fh_name}' in both create_fhs and attach_fhs") pipe = os.pipe() # fix by noting # that since pipes are unidirectional on some systems, # so we have to 'turn the pipe around' # if we are writing if _fd_modes[fh_name] == "w" or _fd_modes[fh_name] == "wb": pipe = (pipe[1], pipe[0]) os.set_inheritable(pipe[0], True) os.set_inheritable(pipe[1], True) process._pipes[fh_name] = Pipe(pipe[0], pipe[1], 0) for fh_name, fh in list(attach_fhs.items()): process._pipes[fh_name] = Pipe(fh.fileno(), fh.fileno(), 1) = os.fork() if != 0: # start a threaded_waitpid on the child process.thread = threading.Thread(target=threaded_waitpid, name=f"wait{}", args=(process,)) process.thread.start() if == 0: self._as_child(process, gnupg_commands, args) return self._as_parent(process)
[docs] def _as_parent(self, process): """Stuff run after forking in parent""" for k, p in list(process._pipes.items()): if not os.close(p.child) process.handles[k] = os.fdopen(p.parent, _fd_modes[k]) # user doesn't need these del process._pipes return process
[docs] def _as_child(self, process, gnupg_commands, args): """Stuff run after forking in child""" # child for std in _stds: p = process._pipes[std] os.dup2(p.child, getattr(sys, f"__{std}__").fileno()) for k, p in list(process._pipes.items()): if and k not in _stds: # we want the fh to stay open after execing fcntl.fcntl(p.child, fcntl.F_SETFD, 0) fd_args = [] for k, p in list(process._pipes.items()): # set command-line options for non-standard fds if k not in _stds: fd_args.extend([_fd_options[k], f"{p.child:d}"]) if not os.close(p.parent) command = [] + fd_args + self.options.get_args() + gnupg_commands + args os.execvp(command[0], command)
[docs]class Pipe(object): """simple struct holding stuff about pipes we use"""
[docs] def __init__(self, parent, child, direct): self.parent = parent self.child = child = direct
[docs]class Options(object): """Objects of this class encompass options passed to GnuPG. This class is responsible for determining command-line arguments which are based on options. It can be said that a GnuPG object has-a Options object in its options attribute. Attributes which correlate directly to GnuPG options: Each option here defaults to false or None, and is described in GnuPG documentation. Booleans (set these attributes to booleans) * armor * no_greeting * no_verbose * quiet * batch * always_trust * rfc1991 * openpgp * force_v3_sigs * no_options * textmode Strings (set these attributes to strings) * homedir * default_key * comment * compress_algo * options Lists (set these attributes to lists) * recipients (***NOTE*** plural of 'recipient') * encrypt_to Meta options Meta options are options provided by this module that do not correlate directly to any GnuPG option by name, but are rather bundle of options used to accomplish a specific goal, such as obtaining compatibility with PGP 5. The actual arguments each of these reflects may change with time. Each defaults to false unless otherwise specified. meta_pgp_5_compatible -- If true, arguments are generated to try to be compatible with PGP 5.x. meta_pgp_2_compatible -- If true, arguments are generated to try to be compatible with PGP 2.x. meta_interactive -- If false, arguments are generated to try to help the using program use GnuPG in a non-interactive environment, such as CGI scripts. Default is true. extra_args -- Extra option arguments may be passed in via the attribute extra_args, a list. >>> import gpginterface >>> >>> gnupg = gpginterface.GnuPG() >>> gnupg.options.armor = 1 >>> gnupg.options.recipients = ['Alice', 'Bob'] >>> gnupg.options.extra_args = ['--no-secmem-warning'] >>> >>> # no need for users to call this normally; just for show here >>> gnupg.options.get_args() ['--armor', '--recipient', 'Alice', '--recipient', 'Bob', '--no-secmem-warning'] """
[docs] def __init__(self): # booleans self.armor = 0 self.no_greeting = 0 self.verbose = 0 self.no_verbose = 0 self.quiet = 0 self.batch = 0 self.always_trust = 0 self.rfc1991 = 0 self.openpgp = 0 self.force_v3_sigs = 0 self.no_options = 0 self.textmode = 0 # meta-option booleans self.meta_pgp_5_compatible = 0 self.meta_pgp_2_compatible = 0 self.meta_interactive = 1 # strings self.homedir = None self.default_key = None self.comment = None self.compress_algo = None self.options = None # lists self.encrypt_to = [] self.recipients = [] self.hidden_recipients = [] # miscellaneous arguments self.extra_args = []
[docs] def get_args(self): """Generate a list of GnuPG arguments based upon attributes.""" return self.get_meta_args() + self.get_standard_args() + self.extra_args
[docs] def get_standard_args(self): """Generate a list of standard, non-meta or extra arguments""" args = [] if self.homedir is not None: args.extend(["--homedir", self.homedir]) if self.options is not None: args.extend(["--options", self.options]) if self.comment is not None: args.extend(["--comment", self.comment]) if self.compress_algo is not None: args.extend(["--compress-algo", self.compress_algo]) if self.default_key is not None: args.extend(["--default-key", self.default_key]) if self.no_options: args.append("--no-options") if self.armor: args.append("--armor") if self.textmode: args.append("--textmode") if self.no_greeting: args.append("--no-greeting") if self.verbose: args.append("--verbose") if self.no_verbose: args.append("--no-verbose") if self.quiet: args.append("--quiet") if self.batch: args.append("--batch") if self.always_trust: args.append("--always-trust") if self.force_v3_sigs: args.append("--force-v3-sigs") if self.rfc1991: args.append("--rfc1991") if self.openpgp: args.append("--openpgp") for r in self.recipients: args.extend(["--recipient", r]) for r in self.hidden_recipients: args.extend(["--hidden-recipient", r]) for r in self.encrypt_to: args.extend(["--encrypt-to", r]) return args
[docs] def get_meta_args(self): """Get a list of generated meta-arguments""" args = [] if self.meta_pgp_5_compatible: args.extend(["--compress-algo", "1", "--force-v3-sigs"]) if self.meta_pgp_2_compatible: args.append("--rfc1991") if not self.meta_interactive: args.extend(["--batch", "--no-tty"]) return args
[docs]class Process(object): """Objects of this class encompass properties of a GnuPG process spawned by # gnupg is a GnuPG object process = [ '--decrypt' ], stdout = 1 ) out = process.handles['stdout'].read() ... os.waitpid(, 0 ) Data Attributes handles -- This is a map of filehandle-names to the file handles, if any, that were requested via run() and hence are connected to the running GnuPG process. Valid names of this map are only those handles that were requested. pid -- The PID of the spawned GnuPG process. Useful to know, since once should call os.waitpid() to clean up the process, especially if multiple calls are made to run(). """
[docs] def __init__(self) -> object: self._pipes = {} self.handles = {} = None self._waited = None self.thread = None self.returned = None
[docs] def wait(self): """ Wait on threaded_waitpid to exit and examine results. Will raise an IOError if the process exits non-zero. """ if self.returned is None: self.thread.join() if self.returned != 0: raise IOError(f"GnuPG exited non-zero, with code {self.returned >> 8:d}")
[docs]def threaded_waitpid(process): """ When started as a thread with the Process object, thread will execute an immediate waitpid() against the process pid and will collect the process termination info. This will allow us to reap child processes as soon as possible, thus freeing resources quickly. """ try: process.returned = os.waitpid(, 0)[1] except Exception as e: log.Debug(_(f"GPG process {} terminated before wait()")) process.returned = 0
if __name__ == "__main__": import doctest from . import gpginterface doctest.testmod(gpginterface)