File CVE-2018-14647_XML_SetHashSalt-in_elementtree.patch of Package python.11987

From 72ce8c81e2f0faf57d0910d1f9008cb6f9993200 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Tue, 18 Sep 2018 14:38:58 +0200
Subject: [PATCH] [2.7] bpo-34623: Use XML_SetHashSalt in _elementtree
 (GH-9146)

The C accelerated _elementtree module now initializes hash randomization
salt from _Py_HashSecret instead of libexpat's default CPRNG.

Signed-off-by: Christian Heimes <christian@python.org>

https://bugs.python.org/issue34623.
(cherry picked from commit cb5778f00ce48631c7140f33ba242496aaf7102b)

Co-authored-by: Christian Heimes <christian@python.org>
---
 Include/pyexpat.h                                           | 6 ++++--
 .../next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst  | 2 ++
 Modules/_elementtree.c                                      | 5 +++++
 Modules/pyexpat.c                                           | 5 +++++
 4 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst

--- a/Include/pyexpat.h
+++ b/Include/pyexpat.h
@@ -3,10 +3,10 @@
 
 /* note: you must import expat.h before importing this module! */
 
-#define PyExpat_CAPI_MAGIC  "pyexpat.expat_CAPI 1.0"
+#define PyExpat_CAPI_MAGIC  "pyexpat.expat_CAPI 1.1"
 #define PyExpat_CAPSULE_NAME "pyexpat.expat_CAPI"
 
-struct PyExpat_CAPI 
+struct PyExpat_CAPI
 {
     char* magic; /* set to PyExpat_CAPI_MAGIC */
     int size; /* set to sizeof(struct PyExpat_CAPI) */
@@ -43,6 +43,8 @@ struct PyExpat_CAPI
         XML_Parser parser, XML_UnknownEncodingHandler handler,
         void *encodingHandlerData);
     void (*SetUserData)(XML_Parser parser, void *userData);
+    /* might be none for expat < 2.1.0 */
+    int (*SetHashSalt)(XML_Parser parser, unsigned long hash_salt);
     /* always add new stuff to the end! */
 };
 
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -2849,6 +2849,11 @@ xmlparser_getattr(XMLParserObject* self,
         PyErr_SetString(PyExc_AttributeError, name);
         return NULL;
     }
+    /* expat < 2.1.0 has no XML_SetHashSalt() */
+    if (EXPAT(SetHashSalt) != NULL) {
+        EXPAT(SetHashSalt)(self->parser,
+                           (unsigned long)_Py_HashSecret.prefix);
+    }
 
     Py_INCREF(res);
     return res;
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -2044,6 +2044,11 @@ MODULE_INITFUNC(void)
     capi.SetProcessingInstructionHandler = XML_SetProcessingInstructionHandler;
     capi.SetUnknownEncodingHandler = XML_SetUnknownEncodingHandler;
     capi.SetUserData = XML_SetUserData;
+#if XML_COMBINED_VERSION >= 20100
+    capi.SetHashSalt = XML_SetHashSalt;
+#else
+    capi.SetHashSalt = NULL;
+#endif
 
     /* export using capsule */
     capi_object = PyCapsule_New(&capi, PyExpat_CAPSULE_NAME, NULL);