Viewing file:  gpg.py (1.75 KB) -rw-r--r--
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import itertools
import shutil
import tempfile
from glob import glob
from twisted.internet.utils import getProcessOutputAndValue
class InvalidGPGSignature(Exception):
"""Raised when the gpg signature for a given file is invalid."""
def gpg_verify(filename, signature, gpg="/usr/bin/gpg", apt_dir="/etc/apt"):
"""Verify the GPG signature of a file.
@param filename: Path to the file to verify the signature against.
@param signature: Path to signature to use.
@param gpg: Optionally, path to the GPG binary to use.
@param apt_dir: Optionally, path to apt trusted keyring.
@return: a C{Deferred} resulting in C{True} if the signature is
valid, C{False} otherwise.
"""
def remove_gpg_home(ignored):
shutil.rmtree(gpg_home)
return ignored
def check_gpg_exit_code(args):
out, err, code = args
# We want a nice error message with Python 3 as well, so decode the
# bytes here.
out, err = out.decode("ascii"), err.decode("ascii")
if code != 0:
raise InvalidGPGSignature("%s failed (out='%s', err='%s', "
"code='%d')" % (gpg, out, err, code))
gpg_home = tempfile.mkdtemp()
keyrings = tuple(itertools.chain(*[
("--keyring", keyring)
for keyring in sorted(
glob("{}/trusted.gpg".format(apt_dir)) +
glob("{}/trusted.gpg.d/*.gpg".format(apt_dir))
)
]))
args = (
"--no-options", "--homedir", gpg_home, "--no-default-keyring",
"--ignore-time-conflict"
) + keyrings + ("--verify", signature, filename)
result = getProcessOutputAndValue(gpg, args=args)
result.addBoth(remove_gpg_home)
result.addCallback(check_gpg_exit_code)
return result
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