scrapy/scrapy/utils/ssl.py

269 lines
8.9 KiB
Python

from __future__ import annotations
import logging
import ssl
import warnings
from typing import TYPE_CHECKING, Any, TypedDict, TypeVar
import OpenSSL._util as pyOpenSSLutil
import OpenSSL.SSL
import OpenSSL.version
from twisted.internet.ssl import CertificateOptions, TLSVersion
from scrapy.exceptions import ScrapyDeprecationWarning
from scrapy.utils._deps_compat import (
PYOPENSSL_X509_DEPRECATED,
TWISTED_TLS_LIMITS_OFFBY1,
)
from scrapy.utils.python import to_unicode
if TYPE_CHECKING:
from collections.abc import Callable
from OpenSSL.crypto import X509Name
from scrapy.settings import BaseSettings
logger = logging.getLogger(__name__)
_T = TypeVar("_T")
# common
def _get_tls_version_limit(
settings: BaseSettings, setting_name: str, converter: Callable[[str], _T]
) -> _T | None:
setting: str | None = settings[setting_name]
if setting is None:
return None
try:
return converter(setting)
except Exception as ex:
raise ValueError(f"Unknown {setting_name} value: {setting}") from ex
def _get_tls_version_limits(
settings: BaseSettings, converter: Callable[[str], _T]
) -> tuple[_T | None, _T | None]:
return (
_get_tls_version_limit(settings, "DOWNLOAD_TLS_MIN_VERSION", converter),
_get_tls_version_limit(settings, "DOWNLOAD_TLS_MAX_VERSION", converter),
)
# stdlib ssl module utils
_STDLIB_VERSION_MAP: dict[str, ssl.TLSVersion] = {
"TLSv1.0": ssl.TLSVersion.TLSv1,
"TLSv1.1": ssl.TLSVersion.TLSv1_1,
"TLSv1.2": ssl.TLSVersion.TLSv1_2,
"TLSv1.3": ssl.TLSVersion.TLSv1_3,
}
def _make_ssl_context(settings: BaseSettings) -> ssl.SSLContext:
"""Create an :class:`ssl.SSLContext` instance according to the settings.
It's intended to be used in an HTTPS download handler.
"""
tls_min_ver, tls_max_ver = _get_tls_version_limits(
settings, _STDLIB_VERSION_MAP.__getitem__
)
ciphers_setting: str | None = settings["DOWNLOADER_CLIENT_TLS_CIPHERS"]
verify_setting = settings.getbool("DOWNLOAD_VERIFY_CERTIFICATES")
ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
if verify_setting:
ctx.check_hostname = True
ctx.verify_mode = ssl.CERT_REQUIRED
ctx.load_default_certs()
else:
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE
if tls_min_ver is not None:
ctx.minimum_version = tls_min_ver
if tls_max_ver is not None:
ctx.maximum_version = tls_max_ver
if ciphers_setting:
ctx.set_ciphers(ciphers_setting)
return ctx
def _make_insecure_ssl_ctx() -> ssl.SSLContext:
"""Create an SSL context that doesn't verify certificates.
Compared to :func:`~scrapy.utils.ssl._make_ssl_context` this is much more
simple.
"""
ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE
return ctx
def _log_sslobj_debug_info(sslobj: ssl.SSLObject) -> None:
cipher = sslobj.cipher()
logger.debug(
f"SSL connection to {sslobj.server_hostname}"
f" using protocol {sslobj.version()},"
f" cipher {cipher[0] if cipher else None}"
)
if cert := sslobj.getpeercert():
# Not available without certificate verification
logger.debug(
f'SSL connection certificate: issuer "{cert["issuer"]}", subject "{cert["subject"]}"'
)
# pyOpenSSL utils
def _ffi_buf_to_string(buf: Any) -> str:
return to_unicode(pyOpenSSLutil.ffi.string(buf))
def ffi_buf_to_string(buf: Any) -> str: # pragma: no cover
warnings.warn(
"ffi_buf_to_string() is deprecated.",
ScrapyDeprecationWarning,
stacklevel=2,
)
return ffi_buf_to_string(buf)
def _x509name_to_string(x509name: X509Name) -> str:
# from OpenSSL.crypto.X509Name.__repr__
# only used on pyOpenSSL < 24.3.0
result_buffer: Any = pyOpenSSLutil.ffi.new("char[]", 512)
pyOpenSSLutil.lib.X509_NAME_oneline(
x509name._name, result_buffer, len(result_buffer)
)
return _ffi_buf_to_string(result_buffer)
def x509name_to_string(x509name: X509Name) -> str: # pragma: no cover
warnings.warn(
"x509name_to_string() is deprecated.",
ScrapyDeprecationWarning,
stacklevel=2,
)
return _x509name_to_string(x509name)
def _get_temp_key_info(ssl_object: Any) -> str | None:
# adapted from OpenSSL apps/s_cb.c::ssl_print_tmp_key()
if not hasattr(pyOpenSSLutil.lib, "SSL_get_server_tmp_key"):
# removed in cryptography 40.0.0 (required starting from pyOpenSSL 23.1.0)
return None
temp_key_p = pyOpenSSLutil.ffi.new("EVP_PKEY **")
if not pyOpenSSLutil.lib.SSL_get_server_tmp_key(ssl_object, temp_key_p):
return None
temp_key = temp_key_p[0]
if temp_key == pyOpenSSLutil.ffi.NULL:
return None
temp_key = pyOpenSSLutil.ffi.gc(temp_key, pyOpenSSLutil.lib.EVP_PKEY_free)
key_info = []
key_type = pyOpenSSLutil.lib.EVP_PKEY_id(temp_key)
if key_type == pyOpenSSLutil.lib.EVP_PKEY_RSA:
key_info.append("RSA")
elif key_type == pyOpenSSLutil.lib.EVP_PKEY_DH:
key_info.append("DH")
elif key_type == pyOpenSSLutil.lib.EVP_PKEY_EC:
key_info.append("ECDH")
ec_key = pyOpenSSLutil.lib.EVP_PKEY_get1_EC_KEY(temp_key)
ec_key = pyOpenSSLutil.ffi.gc(ec_key, pyOpenSSLutil.lib.EC_KEY_free)
nid = pyOpenSSLutil.lib.EC_GROUP_get_curve_name(
pyOpenSSLutil.lib.EC_KEY_get0_group(ec_key)
)
cname = pyOpenSSLutil.lib.EC_curve_nid2nist(nid)
if cname == pyOpenSSLutil.ffi.NULL:
cname = pyOpenSSLutil.lib.OBJ_nid2sn(nid)
key_info.append(_ffi_buf_to_string(cname))
else:
key_info.append(_ffi_buf_to_string(pyOpenSSLutil.lib.OBJ_nid2sn(key_type)))
key_info.append(f"{pyOpenSSLutil.lib.EVP_PKEY_bits(temp_key)} bits")
return ", ".join(key_info)
def get_temp_key_info(ssl_object: Any) -> str | None: # pragma: no cover
warnings.warn(
"get_temp_key_info() is deprecated. It's also a no-op with cryptography 40.0.0+.",
ScrapyDeprecationWarning,
stacklevel=2,
)
return _get_temp_key_info(ssl_object)
def get_openssl_version() -> str:
system_openssl_bytes = OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION)
system_openssl = system_openssl_bytes.decode("ascii", errors="replace")
return f"{OpenSSL.version.__version__} ({system_openssl})"
def _log_ssl_conn_debug_info(hostname: str, connection: OpenSSL.SSL.Connection) -> None:
logger.debug(
"SSL connection to %s using protocol %s, cipher %s",
hostname,
connection.get_protocol_version_name(),
connection.get_cipher_name(),
)
if PYOPENSSL_X509_DEPRECATED:
if server_cert := connection.get_peer_certificate(as_cryptography=True):
logger.debug(
'SSL connection certificate: issuer "%s", subject "%s"',
server_cert.issuer.rfc4514_string(),
server_cert.subject.rfc4514_string(),
)
else: # noqa: PLR5501
if server_cert_pyopenssl := connection.get_peer_certificate():
logger.debug(
'SSL connection certificate: issuer "%s", subject "%s"',
_x509name_to_string(server_cert_pyopenssl.get_issuer()),
_x509name_to_string(server_cert_pyopenssl.get_subject()),
)
key_info = _get_temp_key_info(connection._ssl)
if key_info:
logger.debug("SSL temp key: %s", key_info)
# Twisted-specific
class _CertificateOptionsVersionKwargs(TypedDict, total=False):
lowerMaximumSecurityTo: TLSVersion
insecurelyLowerMinimumTo: TLSVersion
raiseMinimumTo: TLSVersion
def _get_cert_options_version_kwargs(
min_version: TLSVersion | None, max_version: TLSVersion | None
) -> _CertificateOptionsVersionKwargs:
"""Get TLS version kwargs for
:class:`~twisted.internet.ssl.CertificateOptions` for the given limits."""
result: _CertificateOptionsVersionKwargs = {}
if max_version:
if TWISTED_TLS_LIMITS_OFFBY1:
# lowerMaximumSecurityTo is treated as 1 version lower than the passed one
versions = list(TLSVersion.iterconstants())
max_index = versions.index(max_version)
if max_index + 1 >= len(versions):
raise ValueError(
f"Due to an error in Twisted < 26.4.0 cannot set the maximum TLS version to {max_version.name}"
)
max_version = versions[max_index + 1]
result["lowerMaximumSecurityTo"] = max_version
if min_version:
# We cannot pass both insecurelyLowerMinimumTo and raiseMinimumTo,
# so we need to know the direction.
# 1.0 in Twisted 22.8.0 and older, 1.2 in Twisted 22.10.0 and newer
default_min = CertificateOptions._defaultMinimumTLSVersion
if min_version < default_min:
result["insecurelyLowerMinimumTo"] = min_version
elif min_version > default_min:
result["raiseMinimumTo"] = min_version
return result