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Editing: _macos.py
import contextlib import ctypes import platform import ssl import typing from ctypes import ( CDLL, POINTER, c_bool, c_char_p, c_int32, c_long, c_uint32, c_ulong, c_void_p, ) from ctypes.util import find_library from ._ssl_constants import _set_ssl_context_verify_mode _mac_version = platform.mac_ver()[0] _mac_version_info = tuple(map(int, _mac_version.split("."))) if _mac_version_info < (10, 8): raise ImportError( f"Only OS X 10.8 and newer are supported, not {_mac_version_info[0]}.{_mac_version_info[1]}" ) _is_macos_version_10_14_or_later = _mac_version_info >= (10, 14) def _load_cdll(name: str, macos10_16_path: str) -> CDLL: """Loads a CDLL by name, falling back to known path on 10.16+""" try: # Big Sur is technically 11 but we use 10.16 due to the Big Sur # beta being labeled as 10.16. path: str | None if _mac_version_info >= (10, 16): path = macos10_16_path else: path = find_library(name) if not path: raise OSError # Caught and reraised as 'ImportError' return CDLL(path, use_errno=True) except OSError: raise ImportError(f"The library {name} failed to load") from None Security = _load_cdll( "Security", "/System/Library/Frameworks/Security.framework/Security" ) CoreFoundation = _load_cdll( "CoreFoundation", "/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation", ) Boolean = c_bool CFIndex = c_long CFStringEncoding = c_uint32 CFData = c_void_p CFString = c_void_p CFArray = c_void_p CFMutableArray = c_void_p CFError = c_void_p CFType = c_void_p CFTypeID = c_ulong CFTypeRef = POINTER(CFType) CFAllocatorRef = c_void_p OSStatus = c_int32 CFErrorRef = POINTER(CFError) CFDataRef = POINTER(CFData) CFStringRef = POINTER(CFString) CFArrayRef = POINTER(CFArray) CFMutableArrayRef = POINTER(CFMutableArray) CFArrayCallBacks = c_void_p CFOptionFlags = c_uint32 SecCertificateRef = POINTER(c_void_p) SecPolicyRef = POINTER(c_void_p) SecTrustRef = POINTER(c_void_p) SecTrustResultType = c_uint32 SecTrustOptionFlags = c_uint32 try: Security.SecCertificateCreateWithData.argtypes = [CFAllocatorRef, CFDataRef] Security.SecCertificateCreateWithData.restype = SecCertificateRef Security.SecCertificateCopyData.argtypes = [SecCertificateRef] Security.SecCertificateCopyData.restype = CFDataRef Security.SecCopyErrorMessageString.argtypes = [OSStatus, c_void_p] Security.SecCopyErrorMessageString.restype = CFStringRef Security.SecTrustSetAnchorCertificates.argtypes = [SecTrustRef, CFArrayRef] Security.SecTrustSetAnchorCertificates.restype = OSStatus Security.SecTrustSetAnchorCertificatesOnly.argtypes = [SecTrustRef, Boolean] Security.SecTrustSetAnchorCertificatesOnly.restype = OSStatus Security.SecPolicyCreateRevocation.argtypes = [CFOptionFlags] Security.SecPolicyCreateRevocation.restype = SecPolicyRef Security.SecPolicyCreateSSL.argtypes = [Boolean, CFStringRef] Security.SecPolicyCreateSSL.restype = SecPolicyRef Security.SecTrustCreateWithCertificates.argtypes = [ CFTypeRef, CFTypeRef, POINTER(SecTrustRef), ] Security.SecTrustCreateWithCertificates.restype = OSStatus Security.SecTrustGetTrustResult.argtypes = [ SecTrustRef, POINTER(SecTrustResultType), ] Security.SecTrustGetTrustResult.restype = OSStatus Security.SecTrustEvaluate.argtypes = [ SecTrustRef, POINTER(SecTrustResultType), ] Security.SecTrustEvaluate.restype = OSStatus Security.SecTrustRef = SecTrustRef # type: ignore[attr-defined] Security.SecTrustResultType = SecTrustResultType # type: ignore[attr-defined] Security.OSStatus = OSStatus # type: ignore[attr-defined] kSecRevocationUseAnyAvailableMethod = 3 kSecRevocationRequirePositiveResponse = 8 CoreFoundation.CFRelease.argtypes = [CFTypeRef] CoreFoundation.CFRelease.restype = None CoreFoundation.CFGetTypeID.argtypes = [CFTypeRef] CoreFoundation.CFGetTypeID.restype = CFTypeID CoreFoundation.CFStringCreateWithCString.argtypes = [ CFAllocatorRef, c_char_p, CFStringEncoding, ] CoreFoundation.CFStringCreateWithCString.restype = CFStringRef CoreFoundation.CFStringGetCStringPtr.argtypes = [CFStringRef, CFStringEncoding] CoreFoundation.CFStringGetCStringPtr.restype = c_char_p CoreFoundation.CFStringGetCString.argtypes = [ CFStringRef, c_char_p, CFIndex, CFStringEncoding, ] CoreFoundation.CFStringGetCString.restype = c_bool CoreFoundation.CFDataCreate.argtypes = [CFAllocatorRef, c_char_p, CFIndex] CoreFoundation.CFDataCreate.restype = CFDataRef CoreFoundation.CFDataGetLength.argtypes = [CFDataRef] CoreFoundation.CFDataGetLength.restype = CFIndex CoreFoundation.CFDataGetBytePtr.argtypes = [CFDataRef] CoreFoundation.CFDataGetBytePtr.restype = c_void_p CoreFoundation.CFArrayCreate.argtypes = [ CFAllocatorRef, POINTER(CFTypeRef), CFIndex, CFArrayCallBacks, ] CoreFoundation.CFArrayCreate.restype = CFArrayRef CoreFoundation.CFArrayCreateMutable.argtypes = [ CFAllocatorRef, CFIndex, CFArrayCallBacks, ] CoreFoundation.CFArrayCreateMutable.restype = CFMutableArrayRef CoreFoundation.CFArrayAppendValue.argtypes = [CFMutableArrayRef, c_void_p] CoreFoundation.CFArrayAppendValue.restype = None CoreFoundation.CFArrayGetCount.argtypes = [CFArrayRef] CoreFoundation.CFArrayGetCount.restype = CFIndex CoreFoundation.CFArrayGetValueAtIndex.argtypes = [CFArrayRef, CFIndex] CoreFoundation.CFArrayGetValueAtIndex.restype = c_void_p CoreFoundation.CFErrorGetCode.argtypes = [CFErrorRef] CoreFoundation.CFErrorGetCode.restype = CFIndex CoreFoundation.CFErrorCopyDescription.argtypes = [CFErrorRef] CoreFoundation.CFErrorCopyDescription.restype = CFStringRef CoreFoundation.kCFAllocatorDefault = CFAllocatorRef.in_dll( # type: ignore[attr-defined] CoreFoundation, "kCFAllocatorDefault" ) CoreFoundation.kCFTypeArrayCallBacks = c_void_p.in_dll( # type: ignore[attr-defined] CoreFoundation, "kCFTypeArrayCallBacks" ) CoreFoundation.CFTypeRef = CFTypeRef # type: ignore[attr-defined] CoreFoundation.CFArrayRef = CFArrayRef # type: ignore[attr-defined] CoreFoundation.CFStringRef = CFStringRef # type: ignore[attr-defined] CoreFoundation.CFErrorRef = CFErrorRef # type: ignore[attr-defined] except AttributeError as e: raise ImportError(f"Error initializing ctypes: {e}") from None # SecTrustEvaluateWithError is macOS 10.14+ if _is_macos_version_10_14_or_later: try: Security.SecTrustEvaluateWithError.argtypes = [ SecTrustRef, POINTER(CFErrorRef), ] Security.SecTrustEvaluateWithError.restype = c_bool except AttributeError as e: raise ImportError(f"Error initializing ctypes: {e}") from None def _handle_osstatus(result: OSStatus, _: typing.Any, args: typing.Any) -> typing.Any: """ Raises an error if the OSStatus value is non-zero. """ if int(result) == 0: return args # Returns a CFString which we need to transform # into a UTF-8 Python string. error_message_cfstring = None try: error_message_cfstring = Security.SecCopyErrorMessageString(result, None) # First step is convert the CFString into a C string pointer. # We try the fast no-copy way first. error_message_cfstring_c_void_p = ctypes.cast( error_message_cfstring, ctypes.POINTER(ctypes.c_void_p) ) message = CoreFoundation.CFStringGetCStringPtr( error_message_cfstring_c_void_p, CFConst.kCFStringEncodingUTF8 ) # Quoting the Apple dev docs: # # "A pointer to a C string or NULL if the internal # storage of theString does not allow this to be # returned efficiently." # # So we need to get our hands dirty. if message is None: buffer = ctypes.create_string_buffer(1024) result = CoreFoundation.CFStringGetCString( error_message_cfstring_c_void_p, buffer, 1024, CFConst.kCFStringEncodingUTF8, ) if not result: raise OSError("Error copying C string from CFStringRef") message = buffer.value finally: if error_message_cfstring is not None: CoreFoundation.CFRelease(error_message_cfstring) # If no message can be found for this status we come # up with a generic one that forwards the status code. if message is None or message == "": message = f"SecureTransport operation returned a non-zero OSStatus: {result}" raise ssl.SSLError(message) Security.SecTrustCreateWithCertificates.errcheck = _handle_osstatus # type: ignore[assignment] Security.SecTrustSetAnchorCertificates.errcheck = _handle_osstatus # type: ignore[assignment] Security.SecTrustSetAnchorCertificatesOnly.errcheck = _handle_osstatus # type: ignore[assignment] Security.SecTrustGetTrustResult.errcheck = _handle_osstatus # type: ignore[assignment] Security.SecTrustEvaluate.errcheck = _handle_osstatus # type: ignore[assignment] class CFConst: """CoreFoundation constants""" kCFStringEncodingUTF8 = CFStringEncoding(0x08000100) errSecIncompleteCertRevocationCheck = -67635 errSecHostNameMismatch = -67602 errSecCertificateExpired = -67818 errSecNotTrusted = -67843 def _bytes_to_cf_data_ref(value: bytes) -> CFDataRef: # type: ignore[valid-type] return CoreFoundation.CFDataCreate( # type: ignore[no-any-return] CoreFoundation.kCFAllocatorDefault, value, len(value) ) def _bytes_to_cf_string(value: bytes) -> CFString: """ Given a Python binary data, create a CFString. The string must be CFReleased by the caller. """ c_str = ctypes.c_char_p(value) cf_str = CoreFoundation.CFStringCreateWithCString( CoreFoundation.kCFAllocatorDefault, c_str, CFConst.kCFStringEncodingUTF8, ) return cf_str # type: ignore[no-any-return] def _cf_string_ref_to_str(cf_string_ref: CFStringRef) -> str | None: # type: ignore[valid-type] """ Creates a Unicode string from a CFString object. Used entirely for error reporting. Yes, it annoys me quite a lot that this function is this complex. """ string = CoreFoundation.CFStringGetCStringPtr( cf_string_ref, CFConst.kCFStringEncodingUTF8 ) if string is None: buffer = ctypes.create_string_buffer(1024) result = CoreFoundation.CFStringGetCString( cf_string_ref, buffer, 1024, CFConst.kCFStringEncodingUTF8 ) if not result: raise OSError("Error copying C string from CFStringRef") string = buffer.value if string is not None: string = string.decode("utf-8") return string # type: ignore[no-any-return] def _der_certs_to_cf_cert_array(certs: list[bytes]) -> CFMutableArrayRef: # type: ignore[valid-type] """Builds a CFArray of SecCertificateRefs from a list of DER-encoded certificates. Responsibility of the caller to call CoreFoundation.CFRelease on the CFArray. """ cf_array = CoreFoundation.CFArrayCreateMutable( CoreFoundation.kCFAllocatorDefault, 0, ctypes.byref(CoreFoundation.kCFTypeArrayCallBacks), ) if not cf_array: raise MemoryError("Unable to allocate memory!") for cert_data in certs: cf_data = None sec_cert_ref = None try: cf_data = _bytes_to_cf_data_ref(cert_data) sec_cert_ref = Security.SecCertificateCreateWithData( CoreFoundation.kCFAllocatorDefault, cf_data ) CoreFoundation.CFArrayAppendValue(cf_array, sec_cert_ref) finally: if cf_data: CoreFoundation.CFRelease(cf_data) if sec_cert_ref: CoreFoundation.CFRelease(sec_cert_ref) return cf_array # type: ignore[no-any-return] @contextlib.contextmanager def _configure_context(ctx: ssl.SSLContext) -> typing.Iterator[None]: check_hostname = ctx.check_hostname verify_mode = ctx.verify_mode ctx.check_hostname = False _set_ssl_context_verify_mode(ctx, ssl.CERT_NONE) try: yield finally: ctx.check_hostname = check_hostname _set_ssl_context_verify_mode(ctx, verify_mode) def _verify_peercerts_impl( ssl_context: ssl.SSLContext, cert_chain: list[bytes], server_hostname: str | None = None, ) -> None: certs = None policies = None trust = None try: # Only set a hostname on the policy if we're verifying the hostname # on the leaf certificate. if server_hostname is not None and ssl_context.check_hostname: cf_str_hostname = None try: cf_str_hostname = _bytes_to_cf_string(server_hostname.encode("ascii")) ssl_policy = Security.SecPolicyCreateSSL(True, cf_str_hostname) finally: if cf_str_hostname: CoreFoundation.CFRelease(cf_str_hostname) else: ssl_policy = Security.SecPolicyCreateSSL(True, None) policies = ssl_policy if ssl_context.verify_flags & ssl.VERIFY_CRL_CHECK_CHAIN: # Add explicit policy requiring positive revocation checks policies = CoreFoundation.CFArrayCreateMutable( CoreFoundation.kCFAllocatorDefault, 0, ctypes.byref(CoreFoundation.kCFTypeArrayCallBacks), ) CoreFoundation.CFArrayAppendValue(policies, ssl_policy) CoreFoundation.CFRelease(ssl_policy) revocation_policy = Security.SecPolicyCreateRevocation( kSecRevocationUseAnyAvailableMethod | kSecRevocationRequirePositiveResponse ) CoreFoundation.CFArrayAppendValue(policies, revocation_policy) CoreFoundation.CFRelease(revocation_policy) elif ssl_context.verify_flags & ssl.VERIFY_CRL_CHECK_LEAF: raise NotImplementedError("VERIFY_CRL_CHECK_LEAF not implemented for macOS") certs = None try: certs = _der_certs_to_cf_cert_array(cert_chain) # Now that we have certificates loaded and a SecPolicy # we can finally create a SecTrust object! trust = Security.SecTrustRef() Security.SecTrustCreateWithCertificates( certs, policies, ctypes.byref(trust) ) finally: # The certs are now being held by SecTrust so we can # release our handles for the array. if certs: CoreFoundation.CFRelease(certs) # If there are additional trust anchors to load we need to transform # the list of DER-encoded certificates into a CFArray. ctx_ca_certs_der: list[bytes] | None = ssl_context.get_ca_certs( binary_form=True ) if ctx_ca_certs_der: ctx_ca_certs = None try: ctx_ca_certs = _der_certs_to_cf_cert_array(ctx_ca_certs_der) Security.SecTrustSetAnchorCertificates(trust, ctx_ca_certs) finally: if ctx_ca_certs: CoreFoundation.CFRelease(ctx_ca_certs) # We always want system certificates. Security.SecTrustSetAnchorCertificatesOnly(trust, False) # macOS 10.13 and earlier don't support SecTrustEvaluateWithError() # so we use SecTrustEvaluate() which means we need to construct error # messages ourselves. if _is_macos_version_10_14_or_later: _verify_peercerts_impl_macos_10_14(ssl_context, trust) else: _verify_peercerts_impl_macos_10_13(ssl_context, trust) finally: if policies: CoreFoundation.CFRelease(policies) if trust: CoreFoundation.CFRelease(trust) def _verify_peercerts_impl_macos_10_13( ssl_context: ssl.SSLContext, sec_trust_ref: typing.Any ) -> None: """Verify using 'SecTrustEvaluate' API for macOS 10.13 and earlier. macOS 10.14 added the 'SecTrustEvaluateWithError' API. """ sec_trust_result_type = Security.SecTrustResultType() Security.SecTrustEvaluate(sec_trust_ref, ctypes.byref(sec_trust_result_type)) try: sec_trust_result_type_as_int = int(sec_trust_result_type.value) except (ValueError, TypeError): sec_trust_result_type_as_int = -1 # Apple doesn't document these values in their own API docs. # See: https://github.com/xybp888/iOS-SDKs/blob/master/iPhoneOS13.0.sdk/System/Library/Frameworks/Security.framework/Headers/SecTrust.h#L84 if ( ssl_context.verify_mode == ssl.CERT_REQUIRED and sec_trust_result_type_as_int not in (1, 4) ): # Note that we're not able to ignore only hostname errors # for macOS 10.13 and earlier, so check_hostname=False will # still return an error. sec_trust_result_type_to_message = { 0: "Invalid trust result type", # 1: "Trust evaluation succeeded", 2: "User confirmation required", 3: "User specified that certificate is not trusted", # 4: "Trust result is unspecified", 5: "Recoverable trust failure occurred", 6: "Fatal trust failure occurred", 7: "Other error occurred, certificate may be revoked", } error_message = sec_trust_result_type_to_message.get( sec_trust_result_type_as_int, f"Unknown trust result: {sec_trust_result_type_as_int}", ) err = ssl.SSLCertVerificationError(error_message) err.verify_message = error_message err.verify_code = sec_trust_result_type_as_int raise err def _verify_peercerts_impl_macos_10_14( ssl_context: ssl.SSLContext, sec_trust_ref: typing.Any ) -> None: """Verify using 'SecTrustEvaluateWithError' API for macOS 10.14+.""" cf_error = CoreFoundation.CFErrorRef() sec_trust_eval_result = Security.SecTrustEvaluateWithError( sec_trust_ref, ctypes.byref(cf_error) ) # sec_trust_eval_result is a bool (0 or 1) # where 1 means that the certs are trusted. if sec_trust_eval_result == 1: is_trusted = True elif sec_trust_eval_result == 0: is_trusted = False else: raise ssl.SSLError( f"Unknown result from Security.SecTrustEvaluateWithError: {sec_trust_eval_result!r}" ) cf_error_code = 0 if not is_trusted: cf_error_code = CoreFoundation.CFErrorGetCode(cf_error) # If the error is a known failure that we're # explicitly okay with from SSLContext configuration # we can set is_trusted accordingly. if ssl_context.verify_mode != ssl.CERT_REQUIRED and ( cf_error_code == CFConst.errSecNotTrusted or cf_error_code == CFConst.errSecCertificateExpired ): is_trusted = True # If we're still not trusted then we start to # construct and raise the SSLCertVerificationError. if not is_trusted: cf_error_string_ref = None try: cf_error_string_ref = CoreFoundation.CFErrorCopyDescription(cf_error) # Can this ever return 'None' if there's a CFError? cf_error_message = ( _cf_string_ref_to_str(cf_error_string_ref) or "Certificate verification failed" ) # TODO: Not sure if we need the SecTrustResultType for anything? # We only care whether or not it's a success or failure for now. sec_trust_result_type = Security.SecTrustResultType() Security.SecTrustGetTrustResult( sec_trust_ref, ctypes.byref(sec_trust_result_type) ) err = ssl.SSLCertVerificationError(cf_error_message) err.verify_message = cf_error_message err.verify_code = cf_error_code raise err finally: if cf_error_string_ref: CoreFoundation.CFRelease(cf_error_string_ref)
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