|
|
"""Functions for signing notebooks"""
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Copyright (C) 2014, The IPython Development Team
|
|
|
#
|
|
|
# Distributed under the terms of the BSD License. The full license is in
|
|
|
# the file COPYING, distributed as part of this software.
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Imports
|
|
|
#-----------------------------------------------------------------------------
|
|
|
|
|
|
import base64
|
|
|
from contextlib import contextmanager
|
|
|
import hashlib
|
|
|
from hmac import HMAC
|
|
|
import io
|
|
|
import os
|
|
|
|
|
|
from IPython.utils.py3compat import string_types, unicode_type, cast_bytes
|
|
|
from IPython.utils.traitlets import Instance, Bytes, Enum, Any, Unicode, Bool
|
|
|
from IPython.config import LoggingConfigurable, MultipleInstanceError
|
|
|
from IPython.core.application import BaseIPythonApplication, base_flags
|
|
|
|
|
|
from .current import read, write
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Code
|
|
|
#-----------------------------------------------------------------------------
|
|
|
try:
|
|
|
# Python 3
|
|
|
algorithms = hashlib.algorithms_guaranteed
|
|
|
except AttributeError:
|
|
|
algorithms = hashlib.algorithms
|
|
|
|
|
|
def yield_everything(obj):
|
|
|
"""Yield every item in a container as bytes
|
|
|
|
|
|
Allows any JSONable object to be passed to an HMAC digester
|
|
|
without having to serialize the whole thing.
|
|
|
"""
|
|
|
if isinstance(obj, dict):
|
|
|
for key in sorted(obj):
|
|
|
value = obj[key]
|
|
|
yield cast_bytes(key)
|
|
|
for b in yield_everything(value):
|
|
|
yield b
|
|
|
elif isinstance(obj, (list, tuple)):
|
|
|
for element in obj:
|
|
|
for b in yield_everything(element):
|
|
|
yield b
|
|
|
elif isinstance(obj, unicode_type):
|
|
|
yield obj.encode('utf8')
|
|
|
else:
|
|
|
yield unicode_type(obj).encode('utf8')
|
|
|
|
|
|
|
|
|
@contextmanager
|
|
|
def signature_removed(nb):
|
|
|
"""Context manager for operating on a notebook with its signature removed
|
|
|
|
|
|
Used for excluding the previous signature when computing a notebook's signature.
|
|
|
"""
|
|
|
save_signature = nb['metadata'].pop('signature', None)
|
|
|
try:
|
|
|
yield
|
|
|
finally:
|
|
|
if save_signature is not None:
|
|
|
nb['metadata']['signature'] = save_signature
|
|
|
|
|
|
|
|
|
class NotebookNotary(LoggingConfigurable):
|
|
|
"""A class for computing and verifying notebook signatures."""
|
|
|
|
|
|
profile_dir = Instance("IPython.core.profiledir.ProfileDir")
|
|
|
def _profile_dir_default(self):
|
|
|
from IPython.core.application import BaseIPythonApplication
|
|
|
app = None
|
|
|
try:
|
|
|
if BaseIPythonApplication.initialized():
|
|
|
app = BaseIPythonApplication.instance()
|
|
|
except MultipleInstanceError:
|
|
|
pass
|
|
|
if app is None:
|
|
|
# create an app, without the global instance
|
|
|
app = BaseIPythonApplication()
|
|
|
app.initialize()
|
|
|
return app.profile_dir
|
|
|
|
|
|
algorithm = Enum(algorithms, default_value='sha256', config=True,
|
|
|
help="""The hashing algorithm used to sign notebooks."""
|
|
|
)
|
|
|
def _algorithm_changed(self, name, old, new):
|
|
|
self.digestmod = getattr(hashlib, self.algorithm)
|
|
|
|
|
|
digestmod = Any()
|
|
|
def _digestmod_default(self):
|
|
|
return getattr(hashlib, self.algorithm)
|
|
|
|
|
|
secret_file = Unicode()
|
|
|
def _secret_file_default(self):
|
|
|
if self.profile_dir is None:
|
|
|
return ''
|
|
|
return os.path.join(self.profile_dir.security_dir, 'notebook_secret')
|
|
|
|
|
|
secret = Bytes(config=True,
|
|
|
help="""The secret key with which notebooks are signed."""
|
|
|
)
|
|
|
def _secret_default(self):
|
|
|
# note : this assumes an Application is running
|
|
|
if os.path.exists(self.secret_file):
|
|
|
with io.open(self.secret_file, 'rb') as f:
|
|
|
return f.read()
|
|
|
else:
|
|
|
secret = base64.encodestring(os.urandom(1024))
|
|
|
self._write_secret_file(secret)
|
|
|
return secret
|
|
|
|
|
|
def _write_secret_file(self, secret):
|
|
|
"""write my secret to my secret_file"""
|
|
|
self.log.info("Writing notebook-signing key to %s", self.secret_file)
|
|
|
with io.open(self.secret_file, 'wb') as f:
|
|
|
f.write(secret)
|
|
|
try:
|
|
|
os.chmod(self.secret_file, 0o600)
|
|
|
except OSError:
|
|
|
self.log.warn(
|
|
|
"Could not set permissions on %s",
|
|
|
self.secret_file
|
|
|
)
|
|
|
return secret
|
|
|
|
|
|
def compute_signature(self, nb):
|
|
|
"""Compute a notebook's signature
|
|
|
|
|
|
by hashing the entire contents of the notebook via HMAC digest.
|
|
|
"""
|
|
|
hmac = HMAC(self.secret, digestmod=self.digestmod)
|
|
|
# don't include the previous hash in the content to hash
|
|
|
with signature_removed(nb):
|
|
|
# sign the whole thing
|
|
|
for b in yield_everything(nb):
|
|
|
hmac.update(b)
|
|
|
|
|
|
return hmac.hexdigest()
|
|
|
|
|
|
def check_signature(self, nb):
|
|
|
"""Check a notebook's stored signature
|
|
|
|
|
|
If a signature is stored in the notebook's metadata,
|
|
|
a new signature is computed and compared with the stored value.
|
|
|
|
|
|
Returns True if the signature is found and matches, False otherwise.
|
|
|
|
|
|
The following conditions must all be met for a notebook to be trusted:
|
|
|
- a signature is stored in the form 'scheme:hexdigest'
|
|
|
- the stored scheme matches the requested scheme
|
|
|
- the requested scheme is available from hashlib
|
|
|
- the computed hash from notebook_signature matches the stored hash
|
|
|
"""
|
|
|
stored_signature = nb['metadata'].get('signature', None)
|
|
|
if not stored_signature \
|
|
|
or not isinstance(stored_signature, string_types) \
|
|
|
or ':' not in stored_signature:
|
|
|
return False
|
|
|
stored_algo, sig = stored_signature.split(':', 1)
|
|
|
if self.algorithm != stored_algo:
|
|
|
return False
|
|
|
my_signature = self.compute_signature(nb)
|
|
|
return my_signature == sig
|
|
|
|
|
|
def sign(self, nb):
|
|
|
"""Sign a notebook, indicating that its output is trusted
|
|
|
|
|
|
stores 'algo:hmac-hexdigest' in notebook.metadata.signature
|
|
|
|
|
|
e.g. 'sha256:deadbeef123...'
|
|
|
"""
|
|
|
signature = self.compute_signature(nb)
|
|
|
nb['metadata']['signature'] = "%s:%s" % (self.algorithm, signature)
|
|
|
|
|
|
def mark_cells(self, nb, trusted):
|
|
|
"""Mark cells as trusted if the notebook's signature can be verified
|
|
|
|
|
|
Sets ``cell.trusted = True | False`` on all code cells,
|
|
|
depending on whether the stored signature can be verified.
|
|
|
|
|
|
This function is the inverse of check_cells
|
|
|
"""
|
|
|
if not nb['worksheets']:
|
|
|
# nothing to mark if there are no cells
|
|
|
return
|
|
|
for cell in nb['worksheets'][0]['cells']:
|
|
|
if cell['cell_type'] == 'code':
|
|
|
cell['trusted'] = trusted
|
|
|
|
|
|
def check_cells(self, nb):
|
|
|
"""Return whether all code cells are trusted
|
|
|
|
|
|
If there are no code cells, return True.
|
|
|
|
|
|
This function is the inverse of mark_cells.
|
|
|
"""
|
|
|
if not nb['worksheets']:
|
|
|
return True
|
|
|
for cell in nb['worksheets'][0]['cells']:
|
|
|
if cell['cell_type'] != 'code':
|
|
|
continue
|
|
|
if not cell.get('trusted', False):
|
|
|
return False
|
|
|
return True
|
|
|
|
|
|
|
|
|
trust_flags = {
|
|
|
'reset' : (
|
|
|
{'TrustNotebookApp' : { 'reset' : True}},
|
|
|
"""Generate a new key for notebook signature.
|
|
|
All previously signed notebooks will become untrusted.
|
|
|
"""
|
|
|
),
|
|
|
}
|
|
|
trust_flags.update(base_flags)
|
|
|
trust_flags.pop('init')
|
|
|
|
|
|
|
|
|
class TrustNotebookApp(BaseIPythonApplication):
|
|
|
|
|
|
description="""Sign one or more IPython notebooks with your key,
|
|
|
to trust their dynamic (HTML, Javascript) output.
|
|
|
|
|
|
Otherwise, you will have to re-execute the notebook to see output.
|
|
|
"""
|
|
|
|
|
|
examples = """ipython trust mynotebook.ipynb and_this_one.ipynb"""
|
|
|
|
|
|
flags = trust_flags
|
|
|
|
|
|
reset = Bool(False, config=True,
|
|
|
help="""If True, generate a new key for notebook signature.
|
|
|
After reset, all previously signed notebooks will become untrusted.
|
|
|
"""
|
|
|
)
|
|
|
|
|
|
notary = Instance(NotebookNotary)
|
|
|
def _notary_default(self):
|
|
|
return NotebookNotary(parent=self, profile_dir=self.profile_dir)
|
|
|
|
|
|
def sign_notebook(self, notebook_path):
|
|
|
if not os.path.exists(notebook_path):
|
|
|
self.log.error("Notebook missing: %s" % notebook_path)
|
|
|
self.exit(1)
|
|
|
with io.open(notebook_path, encoding='utf8') as f:
|
|
|
nb = read(f, 'json')
|
|
|
if self.notary.check_signature(nb):
|
|
|
print("Notebook already signed: %s" % notebook_path)
|
|
|
else:
|
|
|
print("Signing notebook: %s" % notebook_path)
|
|
|
self.notary.sign(nb)
|
|
|
with io.open(notebook_path, 'w', encoding='utf8') as f:
|
|
|
write(nb, f, 'json')
|
|
|
|
|
|
def generate_new_key(self):
|
|
|
"""Generate a new notebook signature key"""
|
|
|
print("Generating new notebook key: %s" % self.notary.secret_file)
|
|
|
self.notary._write_secret_file(os.urandom(1024))
|
|
|
|
|
|
def start(self):
|
|
|
if self.reset:
|
|
|
self.generate_new_key()
|
|
|
return
|
|
|
if not self.extra_args:
|
|
|
self.log.critical("Specify at least one notebook to sign.")
|
|
|
self.exit(1)
|
|
|
|
|
|
for notebook_path in self.extra_args:
|
|
|
self.sign_notebook(notebook_path)
|
|
|
|
|
|
|
