From 18b20bad75b4ff0486940fba4ec680e96e70f3a2 Mon Sep 17 00:00:00 2001 From: Christian Heimes Date: Tue, 18 Sep 2018 15:13:09 +0200 Subject: [PATCH] [2.7] bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) (GH-9394) The C accelerated _elementtree module now initializes hash randomization salt from _Py_HashSecret instead of libexpat's default CPRNG. Signed-off-by: Christian Heimes https://bugs.python.org/issue34623. (cherry picked from commit cb5778f00ce48631c7140f33ba242496aaf7102b) Co-authored-by: Christian Heimes https://bugs.python.org/issue34623 --- Include/pyexpat.h | 4 +++- .../next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst | 2 ++ Modules/_elementtree.c | 5 +++++ Modules/pyexpat.c | 5 +++++ 4 files changed, 15 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Security/2018-09-10-16-05-39.bpo-34623.Ua9jMv.rst diff --git a/Include/pyexpat.h b/Include/pyexpat.h index 5340ef5fa386..3fc5fa54da63 100644 --- a/Include/pyexpat.h +++ b/Include/pyexpat.h @@ -3,7 +3,7 @@ /* 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 @@ -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! */ }; diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c index f7f992dd3a95..b38e0ab329c7 100644 --- a/Modules/_elementtree.c +++ b/Modules/_elementtree.c @@ -2574,6 +2574,11 @@ xmlparser(PyObject* self_, PyObject* args, PyObject* kw) PyErr_NoMemory(); return NULL; } + /* expat < 2.1.0 has no XML_SetHashSalt() */ + if (EXPAT(SetHashSalt) != NULL) { + EXPAT(SetHashSalt)(self->parser, + (unsigned long)_Py_HashSecret.prefix); + } ALLOC(sizeof(XMLParserObject), "create expatparser"); diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c index 2b4d31293c64..1f8c0d70a559 100644 --- a/Modules/pyexpat.c +++ b/Modules/pyexpat.c @@ -2042,6 +2042,11 @@ 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);