Support DCE IOV functions on macOS

The DCE IOV functions on macOS are not exported by any public header on
the GSS.Framework. This PR defines some macros in the C file that when
compiled against the GSS.Framework will alias the private symbols to the
ones expected by GSSAPI. While the symbols are considered to be private
they haven't changed across any macOS version since the introduction of
GSS.Framework and the inclusion of ext_dce is still dependent on whether
the symbol is present at compile time.

This allows users of this library on macOS to better interop with
Windows SSPI message encryption which typically require the IOV wrapping
functions that were previously unavailable.

The `-framework GSS.framework` has also been removed from the compiler
args as clang emits a warning with these present. They should only be
needed for linking.

Signed-off-by: Jordan Borean <[email protected]>

Author: jborean93

docs/source/gssapi.raw.rst

@@ -116,6 +116,10 @@ DCE (IOV/AEAD) Extensions
     :members:
     :undoc-members:
 
+.. automodule:: gssapi.raw.ext_dce_aead
+    :members:
+    :undoc-members:
+
 IOV MIC Extensions
 ~~~~~~~~~~~~~~~~~~
 

gssapi/raw/__init__.py

@@ -111,14 +111,20 @@
 except ImportError:
     pass
 
-# optional DCE (IOV/AEAD) support
+# optional DCE (IOV) support
 try:
     from gssapi.raw.ext_dce import *  # noqa
     # optional IOV MIC support (requires DCE support)
     from gssapi.raw.ext_iov_mic import *  # noqa
 except ImportError:
     pass
 
+# optional DCE (AEAD) support
+try:
+    from gssapi.raw.ext_dce_aead import *  # noqa
+except ImportError:
+    pass
+
 # optional RFC 6680 support
 try:
     from gssapi.raw.ext_rfc6680 import *  # noqa

gssapi/raw/ext_dce.pyx

@@ -8,15 +8,30 @@ from gssapi.raw.sec_contexts cimport SecurityContext
 
 from gssapi.raw.misc import GSSError
 from gssapi.raw import types as gssapi_types
-from gssapi.raw.named_tuples import IOVUnwrapResult, WrapResult, UnwrapResult
+from gssapi.raw.named_tuples import IOVUnwrapResult
 from collections import namedtuple
 from collections.abc import Sequence
 
 from enum import IntEnum
 from gssapi.raw._enum_extensions import ExtendableEnum
 
+# Kept for backwards compatibility - functions used to be declared here
+try:
+    from gssapi.raw.ext_dce_aead import wrap_aead, unwrap_aead
+except ImportError:
+    pass
+
 
 cdef extern from "python_gssapi_ext.h":
+    """
+    #ifdef OSX_HAS_GSS_FRAMEWORK
+    #define gss_wrap_iov __ApplePrivate_gss_wrap_iov
+    #define gss_unwrap_iov __ApplePrivate_gss_unwrap_iov
+    #define gss_wrap_iov_length __ApplePrivate_gss_wrap_iov_length
+    #define gss_release_iov_buffer __ApplePrivate_gss_release_iov_buffer
+    #endif
+    """
+
     # NB(directxman12): this wiki page has a different argument order
     #                   than the header file, and uses size_t instead of int
     #                   (this file matches the header file)
@@ -37,18 +52,6 @@ cdef extern from "python_gssapi_ext.h":
                                      gss_iov_buffer_desc *iov,
                                      int iov_count) nogil
 
-    OM_uint32 gss_wrap_aead(OM_uint32 *min_stat, gss_ctx_id_t ctx_handle,
-                            int conf_req, gss_qop_t qop_req,
-                            gss_buffer_t input_assoc_buffer,
-                            gss_buffer_t input_payload_buffer, int *conf_ret,
-                            gss_buffer_t output_message_buffer) nogil
-
-    OM_uint32 gss_unwrap_aead(OM_uint32 *min_stat, gss_ctx_id_t ctx_handle,
-                              gss_buffer_t input_message_buffer,
-                              gss_buffer_t input_assoc_buffer,
-                              gss_buffer_t output_payload_buffer,
-                              int *conf_ret, gss_qop_t *qop_ret) nogil
-
     gss_iov_buffer_t GSS_C_NO_IOV_BUFFER
 
     OM_uint32 GSS_IOV_BUFFER_TYPE_EMPTY
@@ -447,109 +450,3 @@ def wrap_iov_length(SecurityContext context not None, IOV message not None,
         return <bint>conf_used
     else:
         raise GSSError(maj_stat, min_stat)
-
-
-def wrap_aead(SecurityContext context not None, bytes message not None,
-              bytes associated=None, confidential=True, qop=None):
-    """
-    wrap_aead(context, message, associated=None, confidential=True, qop=None)
-    Wrap/Encrypt an AEAD message.
-
-    This method takes an input message and associated data,
-    and outputs and AEAD message.
-
-    Args:
-        context (SecurityContext): the current security context
-        message (bytes): the message to wrap or encrypt
-        associated (bytes): associated data to go with the message
-        confidential (bool): whether or not to encrypt the message (True),
-            or just wrap it with a MIC (False)
-        qop (int): the desired Quality of Protection
-            (or None for the default QoP)
-
-    Returns:
-        WrapResult: the wrapped/encrypted total message, and whether or not
-            encryption was actually used
-
-    Raises:
-        GSSError
-    """
-
-    cdef int conf_req = confidential
-    cdef gss_qop_t qop_req = qop if qop is not None else GSS_C_QOP_DEFAULT
-    cdef gss_buffer_desc message_buffer = gss_buffer_desc(len(message),
-                                                          message)
-
-    cdef gss_buffer_t assoc_buffer_ptr = GSS_C_NO_BUFFER
-    cdef gss_buffer_desc assoc_buffer
-    if associated is not None:
-        assoc_buffer = gss_buffer_desc(len(associated), associated)
-        assoc_buffer_ptr = &assoc_buffer
-
-    cdef int conf_used
-    # GSS_C_EMPTY_BUFFER
-    cdef gss_buffer_desc output_buffer = gss_buffer_desc(0, NULL)
-
-    cdef OM_uint32 maj_stat, min_stat
-
-    with nogil:
-        maj_stat = gss_wrap_aead(&min_stat, context.raw_ctx, conf_req, qop_req,
-                                 assoc_buffer_ptr, &message_buffer,
-                                 &conf_used, &output_buffer)
-
-    if maj_stat == GSS_S_COMPLETE:
-        output_message = (<char*>output_buffer.value)[:output_buffer.length]
-        gss_release_buffer(&min_stat, &output_buffer)
-        return WrapResult(output_message, <bint>conf_used)
-    else:
-        raise GSSError(maj_stat, min_stat)
-
-
-def unwrap_aead(SecurityContext context not None, bytes message not None,
-                bytes associated=None):
-    """
-    unwrap_aead(context, message, associated=None)
-    Unwrap/Decrypt an AEAD message.
-
-    This method takes an encrpyted/wrapped AEAD message and some associated
-    data, and returns an unwrapped/decrypted message.
-
-    Args:
-        context (SecurityContext): the current security context
-        message (bytes): the AEAD message to unwrap or decrypt
-        associated (bytes): associated data that goes with the message
-
-    Returns:
-        UnwrapResult: the unwrapped/decrypted message, whether or on
-            encryption was used, and the QoP used
-
-    Raises:
-        GSSError
-    """
-
-    cdef gss_buffer_desc input_buffer = gss_buffer_desc(len(message), message)
-
-    cdef gss_buffer_t assoc_buffer_ptr = GSS_C_NO_BUFFER
-    cdef gss_buffer_desc assoc_buffer
-    if associated is not None:
-        assoc_buffer = gss_buffer_desc(len(associated), associated)
-        assoc_buffer_ptr = &assoc_buffer
-
-    # GSS_C_EMPTY_BUFFER
-    cdef gss_buffer_desc output_buffer = gss_buffer_desc(0, NULL)
-    cdef int conf_state
-    cdef gss_qop_t qop_state
-
-    cdef OM_uint32 maj_stat, min_stat
-
-    with nogil:
-        maj_stat = gss_unwrap_aead(&min_stat, context.raw_ctx, &input_buffer,
-                                   assoc_buffer_ptr, &output_buffer,
-                                   &conf_state, &qop_state)
-
-    if maj_stat == GSS_S_COMPLETE:
-        output_message = (<char*>output_buffer.value)[:output_buffer.length]
-        gss_release_buffer(&min_stat, &output_buffer)
-        return UnwrapResult(output_message, <bint>conf_state, qop_state)
-    else:
-        raise GSSError(maj_stat, min_stat)

gssapi/raw/ext_dce_aead.pyx

@@ -0,0 +1,127 @@
+GSSAPI="BASE"  # This ensures that a full module is generated by Cython
+
+from gssapi.raw.cython_types cimport *
+from gssapi.raw.sec_contexts cimport SecurityContext
+
+from gssapi.raw.misc import GSSError
+from gssapi.raw.named_tuples import WrapResult, UnwrapResult
+
+
+cdef extern from "python_gssapi_ext.h":
+    OM_uint32 gss_wrap_aead(OM_uint32 *min_stat, gss_ctx_id_t ctx_handle,
+                            int conf_req, gss_qop_t qop_req,
+                            gss_buffer_t input_assoc_buffer,
+                            gss_buffer_t input_payload_buffer, int *conf_ret,
+                            gss_buffer_t output_message_buffer) nogil
+
+    OM_uint32 gss_unwrap_aead(OM_uint32 *min_stat, gss_ctx_id_t ctx_handle,
+                              gss_buffer_t input_message_buffer,
+                              gss_buffer_t input_assoc_buffer,
+                              gss_buffer_t output_payload_buffer,
+                              int *conf_ret, gss_qop_t *qop_ret) nogil
+
+
+def wrap_aead(SecurityContext context not None, bytes message not None,
+              bytes associated=None, confidential=True, qop=None):
+    """
+    wrap_aead(context, message, associated=None, confidential=True, qop=None)
+    Wrap/Encrypt an AEAD message.
+
+    This method takes an input message and associated data,
+    and outputs and AEAD message.
+
+    Args:
+        context (SecurityContext): the current security context
+        message (bytes): the message to wrap or encrypt
+        associated (bytes): associated data to go with the message
+        confidential (bool): whether or not to encrypt the message (True),
+            or just wrap it with a MIC (False)
+        qop (int): the desired Quality of Protection
+            (or None for the default QoP)
+
+    Returns:
+        WrapResult: the wrapped/encrypted total message, and whether or not
+            encryption was actually used
+
+    Raises:
+        GSSError
+    """
+
+    cdef int conf_req = confidential
+    cdef gss_qop_t qop_req = qop if qop is not None else GSS_C_QOP_DEFAULT
+    cdef gss_buffer_desc message_buffer = gss_buffer_desc(len(message),
+                                                          message)
+
+    cdef gss_buffer_t assoc_buffer_ptr = GSS_C_NO_BUFFER
+    cdef gss_buffer_desc assoc_buffer
+    if associated is not None:
+        assoc_buffer = gss_buffer_desc(len(associated), associated)
+        assoc_buffer_ptr = &assoc_buffer
+
+    cdef int conf_used
+    # GSS_C_EMPTY_BUFFER
+    cdef gss_buffer_desc output_buffer = gss_buffer_desc(0, NULL)
+
+    cdef OM_uint32 maj_stat, min_stat
+
+    with nogil:
+        maj_stat = gss_wrap_aead(&min_stat, context.raw_ctx, conf_req, qop_req,
+                                 assoc_buffer_ptr, &message_buffer,
+                                 &conf_used, &output_buffer)
+
+    if maj_stat == GSS_S_COMPLETE:
+        output_message = (<char*>output_buffer.value)[:output_buffer.length]
+        gss_release_buffer(&min_stat, &output_buffer)
+        return WrapResult(output_message, <bint>conf_used)
+    else:
+        raise GSSError(maj_stat, min_stat)
+
+
+def unwrap_aead(SecurityContext context not None, bytes message not None,
+                bytes associated=None):
+    """
+    unwrap_aead(context, message, associated=None)
+    Unwrap/Decrypt an AEAD message.
+
+    This method takes an encrpyted/wrapped AEAD message and some associated
+    data, and returns an unwrapped/decrypted message.
+
+    Args:
+        context (SecurityContext): the current security context
+        message (bytes): the AEAD message to unwrap or decrypt
+        associated (bytes): associated data that goes with the message
+
+    Returns:
+        UnwrapResult: the unwrapped/decrypted message, whether or on
+            encryption was used, and the QoP used
+
+    Raises:
+        GSSError
+    """
+
+    cdef gss_buffer_desc input_buffer = gss_buffer_desc(len(message), message)
+
+    cdef gss_buffer_t assoc_buffer_ptr = GSS_C_NO_BUFFER
+    cdef gss_buffer_desc assoc_buffer
+    if associated is not None:
+        assoc_buffer = gss_buffer_desc(len(associated), associated)
+        assoc_buffer_ptr = &assoc_buffer
+
+    # GSS_C_EMPTY_BUFFER
+    cdef gss_buffer_desc output_buffer = gss_buffer_desc(0, NULL)
+    cdef int conf_state
+    cdef gss_qop_t qop_state
+
+    cdef OM_uint32 maj_stat, min_stat
+
+    with nogil:
+        maj_stat = gss_unwrap_aead(&min_stat, context.raw_ctx, &input_buffer,
+                                   assoc_buffer_ptr, &output_buffer,
+                                   &conf_state, &qop_state)
+
+    if maj_stat == GSS_S_COMPLETE:
+        output_message = (<char*>output_buffer.value)[:output_buffer.length]
+        gss_release_buffer(&min_stat, &output_buffer)
+        return UnwrapResult(output_message, <bint>conf_state, qop_state)
+    else:
+        raise GSSError(maj_stat, min_stat)

gssapi/raw/python_gssapi_ext.h

@@ -1,5 +1,37 @@
 #ifdef OSX_HAS_GSS_FRAMEWORK
 #include <GSS/GSS.h>
+
+// GSS includes these in gssapi_private.h but these aren't present on the host
+// so just explicitly define them. They have been slightly modified to follow
+// the krb5 standard. The originals can be found at (introduced macOS 10.7).
+// https://opensource.apple.com/source/Heimdal/Heimdal-172.18/lib/gssapi/gssapi/gssapi_spi.h.auto.html
+OM_uint32 __ApplePrivate_gss_unwrap_iov(OM_uint32 *minor_status,
+                                        gss_ctx_id_t context_handle,
+                                        int *conf_state,
+                                        gss_qop_t *qop_state,
+                                        gss_iov_buffer_desc *iov,
+                                        int iov_count);
+
+OM_uint32 __ApplePrivate_gss_wrap_iov(OM_uint32 *minor_status,
+                                      gss_ctx_id_t context_handle,
+                                      int conf_req_flag,
+                                      gss_qop_t qop_req,
+                                      int *conf_state,
+                                      gss_iov_buffer_desc *iov,
+                                      int iov_count);
+
+OM_uint32 __ApplePrivate_gss_wrap_iov_length(OM_uint32 *minor_status,
+                                             gss_ctx_id_t context_handle,
+                                             int conf_req_flag,
+                                             gss_qop_t qop_req,
+                                             int *conf_state,
+                                             gss_iov_buffer_desc *iov,
+                                             int iov_count);
+
+OM_uint32 __ApplePrivate_gss_release_iov_buffer(OM_uint32 *minor_status,
+                                                gss_iov_buffer_desc *iov,
+                                                int iov_count);
+
 #else
 #if defined(__MINGW32__) && defined(__MSYS__)
 #include <gss.h>

gssapi/tests/test_raw.py

@@ -1304,7 +1304,7 @@ def test_basic_iov_wrap_unwrap_prealloc(self):
         self.assertEqual(init_message[2].value, init_data)
         self.assertEqual(init_message[3].value, init_other_data)
 
-    @ktu.gssapi_extension_test('dce', 'DCE (IOV/AEAD)')
+    @ktu.gssapi_extension_test('dce', 'DCE (IOV)')
     def test_basic_iov_wrap_unwrap_autoalloc(self):
         init_data = b'some encrypted data'
         init_other_data = b'some other encrypted data'
@@ -1334,7 +1334,7 @@ def test_basic_iov_wrap_unwrap_autoalloc(self):
         self.assertEqual(init_message[2].value, init_data)
         self.assertEqual(init_message[3].value, init_other_data)
 
-    @ktu.gssapi_extension_test('dce', 'DCE (IOV/AEAD)')
+    @ktu.gssapi_extension_test('dce_aead', 'DCE (AEAD)')
     def test_basic_aead_wrap_unwrap(self):
         assoc_data = b'some sig data'
         wrapped_message, conf = gb.wrap_aead(self.client_ctx, b"test message",
@@ -1353,7 +1353,7 @@ def test_basic_aead_wrap_unwrap(self):
         self.assertIsInstance(qop, int)
         self.assertGreaterEqual(qop, 0)
 
-    @ktu.gssapi_extension_test('dce', 'DCE (IOV/AEAD)')
+    @ktu.gssapi_extension_test('dce_aead', 'DCE (AEAD)')
     def test_basic_aead_wrap_unwrap_no_assoc(self):
         wrapped_message, conf = gb.wrap_aead(self.client_ctx, b"test message")
         self.assertIsInstance(wrapped_message, bytes)
@@ -1370,7 +1370,7 @@ def test_basic_aead_wrap_unwrap_no_assoc(self):
         self.assertIsInstance(qop, int)
         self.assertGreaterEqual(qop, 0)
 
-    @ktu.gssapi_extension_test('dce', 'DCE (IOV/AEAD)')
+    @ktu.gssapi_extension_test('dce_aead', 'DCE (AEAD)')
     def test_basic_aead_wrap_unwrap_bad_assoc_raises_error(self):
         assoc_data = b'some sig data'
         wrapped_message, conf = gb.wrap_aead(self.client_ctx, b"test message",