sanic/sanic/http/tls/creators.py
2023-10-25 02:28:52 +01:00

290 lines
9.3 KiB
Python

from __future__ import annotations
import ssl
import subprocess
import sys
from abc import ABC, abstractmethod
from contextlib import suppress
from pathlib import Path
from tempfile import mkdtemp
from types import ModuleType
from typing import TYPE_CHECKING, cast
from sanic.application.constants import Mode
from sanic.application.spinner import loading
from sanic.constants import (
DEFAULT_LOCAL_TLS_CERT,
DEFAULT_LOCAL_TLS_KEY,
LocalCertCreator,
)
from sanic.exceptions import SanicException
from sanic.helpers import Default
from sanic.http.tls.context import CertSimple, SanicSSLContext
try:
import trustme
TRUSTME_INSTALLED = True
except (ImportError, ModuleNotFoundError):
trustme = ModuleType("trustme")
TRUSTME_INSTALLED = False
if TYPE_CHECKING:
from sanic import Sanic
# Only allow secure ciphers, notably leaving out AES-CBC mode
# OpenSSL chooses ECDSA or RSA depending on the cert in use
CIPHERS_TLS12 = [
"ECDHE-ECDSA-CHACHA20-POLY1305",
"ECDHE-ECDSA-AES256-GCM-SHA384",
"ECDHE-ECDSA-AES128-GCM-SHA256",
"ECDHE-RSA-CHACHA20-POLY1305",
"ECDHE-RSA-AES256-GCM-SHA384",
"ECDHE-RSA-AES128-GCM-SHA256",
]
def _make_path(maybe_path: Path | str, tmpdir: Path | None) -> Path:
if isinstance(maybe_path, Path):
return maybe_path
else:
path = Path(maybe_path)
if not path.exists():
if not tmpdir:
raise RuntimeError("Reached an unknown state. No tmpdir.")
return tmpdir / maybe_path
return path
def get_ssl_context(
app: Sanic, ssl: ssl.SSLContext | None
) -> ssl.SSLContext:
if ssl:
return ssl
if app.state.mode is Mode.PRODUCTION:
raise SanicException(
"Cannot run Sanic as an HTTPS server in PRODUCTION mode "
"without passing a TLS certificate. If you are developing "
"locally, please enable DEVELOPMENT mode and Sanic will "
"generate a localhost TLS certificate. For more information "
"please see: https://sanic.dev/en/guide/deployment/development."
"html#automatic-tls-certificate."
)
creator = CertCreator.select(
app,
cast(LocalCertCreator, app.config.LOCAL_CERT_CREATOR),
app.config.LOCAL_TLS_KEY,
app.config.LOCAL_TLS_CERT,
)
context = creator.generate_cert(app.config.LOCALHOST)
return context
class CertCreator(ABC):
def __init__(self, app, key, cert) -> None:
self.app = app
self.key = key
self.cert = cert
self.tmpdir = None
if isinstance(self.key, Default) or isinstance(self.cert, Default):
self.tmpdir = Path(mkdtemp())
key = (
DEFAULT_LOCAL_TLS_KEY
if isinstance(self.key, Default)
else self.key
)
cert = (
DEFAULT_LOCAL_TLS_CERT
if isinstance(self.cert, Default)
else self.cert
)
self.key_path = _make_path(key, self.tmpdir)
self.cert_path = _make_path(cert, self.tmpdir)
@abstractmethod
def check_supported(self) -> None: # no cov
...
@abstractmethod
def generate_cert(self, localhost: str) -> ssl.SSLContext: # no cov
...
@classmethod
def select(
cls,
app: Sanic,
cert_creator: LocalCertCreator,
local_tls_key,
local_tls_cert,
) -> CertCreator:
creator: CertCreator | None = None
cert_creator_options: tuple[
tuple[type[CertCreator], LocalCertCreator], ...
] = (
(MkcertCreator, LocalCertCreator.MKCERT),
(TrustmeCreator, LocalCertCreator.TRUSTME),
)
for creator_class, local_creator in cert_creator_options:
creator = cls._try_select(
app,
creator,
creator_class,
local_creator,
cert_creator,
local_tls_key,
local_tls_cert,
)
if creator:
break
if not creator:
raise SanicException(
"Sanic could not find package to create a TLS certificate. "
"You must have either mkcert or trustme installed. See "
"https://sanic.dev/en/guide/deployment/development.html"
"#automatic-tls-certificate for more details."
)
return creator
@staticmethod
def _try_select(
app: Sanic,
creator: CertCreator | None,
creator_class: type[CertCreator],
creator_requirement: LocalCertCreator,
creator_requested: LocalCertCreator,
local_tls_key,
local_tls_cert,
):
if creator or (
creator_requested is not LocalCertCreator.AUTO
and creator_requested is not creator_requirement
):
return creator
instance = creator_class(app, local_tls_key, local_tls_cert)
try:
instance.check_supported()
except SanicException:
if creator_requested is creator_requirement:
raise
else:
return None
return instance
class MkcertCreator(CertCreator):
def check_supported(self) -> None:
try:
subprocess.run( # nosec B603 B607
["mkcert", "-help"],
check=True,
stderr=subprocess.DEVNULL,
stdout=subprocess.DEVNULL,
)
except Exception as e:
raise SanicException(
"Sanic is attempting to use mkcert to generate local TLS "
"certificates since you did not supply a certificate, but "
"one is required. Sanic cannot proceed since mkcert does not "
"appear to be installed. Alternatively, you can use trustme. "
"Please install mkcert, trustme, or supply TLS certificates "
"to proceed. Installation instructions can be found here: "
"https://github.com/FiloSottile/mkcert.\n"
"Find out more information about your options here: "
"https://sanic.dev/en/guide/deployment/development.html#"
"automatic-tls-certificate"
) from e
def generate_cert(self, localhost: str) -> ssl.SSLContext:
try:
if not self.cert_path.exists():
message = "Generating TLS certificate"
# TODO: Validate input for security
with loading(message):
cmd = [
"mkcert",
"-key-file",
str(self.key_path),
"-cert-file",
str(self.cert_path),
localhost,
]
resp = subprocess.run( # nosec B603
cmd,
check=True,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
text=True,
)
sys.stdout.write("\r" + " " * (len(message) + 4))
sys.stdout.flush()
sys.stdout.write(resp.stdout)
finally:
@self.app.main_process_stop
async def cleanup(*_): # no cov
if self.tmpdir:
with suppress(FileNotFoundError):
self.key_path.unlink()
self.cert_path.unlink()
self.tmpdir.rmdir()
context = CertSimple(self.cert_path, self.key_path)
context.sanic["creator"] = "mkcert"
context.sanic["localhost"] = localhost
SanicSSLContext.create_from_ssl_context(context)
return context
class TrustmeCreator(CertCreator):
def check_supported(self) -> None:
if not TRUSTME_INSTALLED:
raise SanicException(
"Sanic is attempting to use trustme to generate local TLS "
"certificates since you did not supply a certificate, but "
"one is required. Sanic cannot proceed since trustme does not "
"appear to be installed. Alternatively, you can use mkcert. "
"Please install mkcert, trustme, or supply TLS certificates "
"to proceed. Installation instructions can be found here: "
"https://github.com/python-trio/trustme.\n"
"Find out more information about your options here: "
"https://sanic.dev/en/guide/deployment/development.html#"
"automatic-tls-certificate"
)
def generate_cert(self, localhost: str) -> ssl.SSLContext:
context = SanicSSLContext.create_from_ssl_context(
ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
)
context.sanic = {
"cert": self.cert_path.absolute(),
"key": self.key_path.absolute(),
}
ca = trustme.CA()
server_cert = ca.issue_cert(localhost)
server_cert.configure_cert(context)
ca.configure_trust(context)
ca.cert_pem.write_to_path(str(self.cert_path.absolute()))
server_cert.private_key_and_cert_chain_pem.write_to_path(
str(self.key_path.absolute())
)
context.sanic["creator"] = "trustme"
context.sanic["localhost"] = localhost
return context