PyBitmessage/rsa/cli.py
2012-11-19 14:45:05 -05:00

380 lines
12 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
'''Commandline scripts.
These scripts are called by the executables defined in setup.py.
'''
from __future__ import with_statement, print_function
import abc
import sys
from optparse import OptionParser
import rsa
import rsa.bigfile
import rsa.pkcs1
HASH_METHODS = sorted(rsa.pkcs1.HASH_METHODS.keys())
def keygen():
'''Key generator.'''
# Parse the CLI options
parser = OptionParser(usage='usage: %prog [options] keysize',
description='Generates a new RSA keypair of "keysize" bits.')
parser.add_option('--pubout', type='string',
help='Output filename for the public key. The public key is '
'not saved if this option is not present. You can use '
'pyrsa-priv2pub to create the public key file later.')
parser.add_option('-o', '--out', type='string',
help='Output filename for the private key. The key is '
'written to stdout if this option is not present.')
parser.add_option('--form',
help='key format of the private and public keys - default PEM',
choices=('PEM', 'DER'), default='PEM')
(cli, cli_args) = parser.parse_args(sys.argv[1:])
if len(cli_args) != 1:
parser.print_help()
raise SystemExit(1)
try:
keysize = int(cli_args[0])
except ValueError:
parser.print_help()
print('Not a valid number: %s' % cli_args[0], file=sys.stderr)
raise SystemExit(1)
print('Generating %i-bit key' % keysize, file=sys.stderr)
(pub_key, priv_key) = rsa.newkeys(keysize)
# Save public key
if cli.pubout:
print('Writing public key to %s' % cli.pubout, file=sys.stderr)
data = pub_key.save_pkcs1(format=cli.form)
with open(cli.pubout, 'wb') as outfile:
outfile.write(data)
# Save private key
data = priv_key.save_pkcs1(format=cli.form)
if cli.out:
print('Writing private key to %s' % cli.out, file=sys.stderr)
with open(cli.out, 'wb') as outfile:
outfile.write(data)
else:
print('Writing private key to stdout', file=sys.stderr)
sys.stdout.write(data)
class CryptoOperation(object):
'''CLI callable that operates with input, output, and a key.'''
__metaclass__ = abc.ABCMeta
keyname = 'public' # or 'private'
usage = 'usage: %%prog [options] %(keyname)s_key'
description = None
operation = 'decrypt'
operation_past = 'decrypted'
operation_progressive = 'decrypting'
input_help = 'Name of the file to %(operation)s. Reads from stdin if ' \
'not specified.'
output_help = 'Name of the file to write the %(operation_past)s file ' \
'to. Written to stdout if this option is not present.'
expected_cli_args = 1
has_output = True
key_class = rsa.PublicKey
def __init__(self):
self.usage = self.usage % self.__class__.__dict__
self.input_help = self.input_help % self.__class__.__dict__
self.output_help = self.output_help % self.__class__.__dict__
@abc.abstractmethod
def perform_operation(self, indata, key, cli_args=None):
'''Performs the program's operation.
Implement in a subclass.
:returns: the data to write to the output.
'''
def __call__(self):
'''Runs the program.'''
(cli, cli_args) = self.parse_cli()
key = self.read_key(cli_args[0], cli.keyform)
indata = self.read_infile(cli.input)
print(self.operation_progressive.title(), file=sys.stderr)
outdata = self.perform_operation(indata, key, cli_args)
if self.has_output:
self.write_outfile(outdata, cli.output)
def parse_cli(self):
'''Parse the CLI options
:returns: (cli_opts, cli_args)
'''
parser = OptionParser(usage=self.usage, description=self.description)
parser.add_option('-i', '--input', type='string', help=self.input_help)
if self.has_output:
parser.add_option('-o', '--output', type='string', help=self.output_help)
parser.add_option('--keyform',
help='Key format of the %s key - default PEM' % self.keyname,
choices=('PEM', 'DER'), default='PEM')
(cli, cli_args) = parser.parse_args(sys.argv[1:])
if len(cli_args) != self.expected_cli_args:
parser.print_help()
raise SystemExit(1)
return (cli, cli_args)
def read_key(self, filename, keyform):
'''Reads a public or private key.'''
print('Reading %s key from %s' % (self.keyname, filename), file=sys.stderr)
with open(filename, 'rb') as keyfile:
keydata = keyfile.read()
return self.key_class.load_pkcs1(keydata, keyform)
def read_infile(self, inname):
'''Read the input file'''
if inname:
print('Reading input from %s' % inname, file=sys.stderr)
with open(inname, 'rb') as infile:
return infile.read()
print('Reading input from stdin', file=sys.stderr)
return sys.stdin.read()
def write_outfile(self, outdata, outname):
'''Write the output file'''
if outname:
print('Writing output to %s' % outname, file=sys.stderr)
with open(outname, 'wb') as outfile:
outfile.write(outdata)
else:
print('Writing output to stdout', file=sys.stderr)
sys.stdout.write(outdata)
class EncryptOperation(CryptoOperation):
'''Encrypts a file.'''
keyname = 'public'
description = ('Encrypts a file. The file must be shorter than the key '
'length in order to be encrypted. For larger files, use the '
'pyrsa-encrypt-bigfile command.')
operation = 'encrypt'
operation_past = 'encrypted'
operation_progressive = 'encrypting'
def perform_operation(self, indata, pub_key, cli_args=None):
'''Encrypts files.'''
return rsa.encrypt(indata, pub_key)
class DecryptOperation(CryptoOperation):
'''Decrypts a file.'''
keyname = 'private'
description = ('Decrypts a file. The original file must be shorter than '
'the key length in order to have been encrypted. For larger '
'files, use the pyrsa-decrypt-bigfile command.')
operation = 'decrypt'
operation_past = 'decrypted'
operation_progressive = 'decrypting'
key_class = rsa.PrivateKey
def perform_operation(self, indata, priv_key, cli_args=None):
'''Decrypts files.'''
return rsa.decrypt(indata, priv_key)
class SignOperation(CryptoOperation):
'''Signs a file.'''
keyname = 'private'
usage = 'usage: %%prog [options] private_key hash_method'
description = ('Signs a file, outputs the signature. Choose the hash '
'method from %s' % ', '.join(HASH_METHODS))
operation = 'sign'
operation_past = 'signature'
operation_progressive = 'Signing'
key_class = rsa.PrivateKey
expected_cli_args = 2
output_help = ('Name of the file to write the signature to. Written '
'to stdout if this option is not present.')
def perform_operation(self, indata, priv_key, cli_args):
'''Decrypts files.'''
hash_method = cli_args[1]
if hash_method not in HASH_METHODS:
raise SystemExit('Invalid hash method, choose one of %s' %
', '.join(HASH_METHODS))
return rsa.sign(indata, priv_key, hash_method)
class VerifyOperation(CryptoOperation):
'''Verify a signature.'''
keyname = 'public'
usage = 'usage: %%prog [options] private_key signature_file'
description = ('Verifies a signature, exits with status 0 upon success, '
'prints an error message and exits with status 1 upon error.')
operation = 'verify'
operation_past = 'verified'
operation_progressive = 'Verifying'
key_class = rsa.PublicKey
expected_cli_args = 2
has_output = False
def perform_operation(self, indata, pub_key, cli_args):
'''Decrypts files.'''
signature_file = cli_args[1]
with open(signature_file, 'rb') as sigfile:
signature = sigfile.read()
try:
rsa.verify(indata, signature, pub_key)
except rsa.VerificationError:
raise SystemExit('Verification failed.')
print('Verification OK', file=sys.stderr)
class BigfileOperation(CryptoOperation):
'''CryptoOperation that doesn't read the entire file into memory.'''
def __init__(self):
CryptoOperation.__init__(self)
self.file_objects = []
def __del__(self):
'''Closes any open file handles.'''
for fobj in self.file_objects:
fobj.close()
def __call__(self):
'''Runs the program.'''
(cli, cli_args) = self.parse_cli()
key = self.read_key(cli_args[0], cli.keyform)
# Get the file handles
infile = self.get_infile(cli.input)
outfile = self.get_outfile(cli.output)
# Call the operation
print(self.operation_progressive.title(), file=sys.stderr)
self.perform_operation(infile, outfile, key, cli_args)
def get_infile(self, inname):
'''Returns the input file object'''
if inname:
print('Reading input from %s' % inname, file=sys.stderr)
fobj = open(inname, 'rb')
self.file_objects.append(fobj)
else:
print('Reading input from stdin', file=sys.stderr)
fobj = sys.stdin
return fobj
def get_outfile(self, outname):
'''Returns the output file object'''
if outname:
print('Will write output to %s' % outname, file=sys.stderr)
fobj = open(outname, 'wb')
self.file_objects.append(fobj)
else:
print('Will write output to stdout', file=sys.stderr)
fobj = sys.stdout
return fobj
class EncryptBigfileOperation(BigfileOperation):
'''Encrypts a file to VARBLOCK format.'''
keyname = 'public'
description = ('Encrypts a file to an encrypted VARBLOCK file. The file '
'can be larger than the key length, but the output file is only '
'compatible with Python-RSA.')
operation = 'encrypt'
operation_past = 'encrypted'
operation_progressive = 'encrypting'
def perform_operation(self, infile, outfile, pub_key, cli_args=None):
'''Encrypts files to VARBLOCK.'''
return rsa.bigfile.encrypt_bigfile(infile, outfile, pub_key)
class DecryptBigfileOperation(BigfileOperation):
'''Decrypts a file in VARBLOCK format.'''
keyname = 'private'
description = ('Decrypts an encrypted VARBLOCK file that was encrypted '
'with pyrsa-encrypt-bigfile')
operation = 'decrypt'
operation_past = 'decrypted'
operation_progressive = 'decrypting'
key_class = rsa.PrivateKey
def perform_operation(self, infile, outfile, priv_key, cli_args=None):
'''Decrypts a VARBLOCK file.'''
return rsa.bigfile.decrypt_bigfile(infile, outfile, priv_key)
encrypt = EncryptOperation()
decrypt = DecryptOperation()
sign = SignOperation()
verify = VerifyOperation()
encrypt_bigfile = EncryptBigfileOperation()
decrypt_bigfile = DecryptBigfileOperation()