From c72c3bed779d9176096abf487ca855aa2871edd8 Mon Sep 17 00:00:00 2001 From: "Andrew M. Kuchling" Date: Wed, 12 Jul 2000 01:27:18 +0000 Subject: Fix bugs in readinst(): * There was no error reported if the .read() method returns a non-string * If read() returned too much data, the buffer would be overflowed causing a core dump * Used strncpy, not memcpy, which seems incorrect if there are embedded \0s. * The args and bytes objects were leaked --- Modules/pyexpat.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c index f0b17c5..05bb703 100644 --- a/Modules/pyexpat.c +++ b/Modules/pyexpat.c @@ -446,7 +446,7 @@ int readinst(char *buf, int buf_size, PyObject *meth){ PyObject *arg=NULL; PyObject *bytes=NULL; PyObject *str=NULL; - int len = 0; + int len = -1; UNLESS(bytes = PyInt_FromLong(buf_size)) { if (!PyErr_Occurred()) @@ -458,20 +458,33 @@ int readinst(char *buf, int buf_size, PyObject *meth){ UNLESS(arg = PyTuple_New(1)) goto finally; - Py_INCREF(bytes); if (PyTuple_SetItem(arg, 0, bytes) < 0) goto finally; UNLESS(str = PyObject_CallObject(meth, arg)) goto finally; - UNLESS(PyString_Check( str )) + /* XXX what to do if it returns a Unicode string? */ + UNLESS(PyString_Check( str )) { + PyErr_Format(PyExc_TypeError, + "read() did not return a string object (type=%.400s)", + str->ob_type->tp_name); goto finally; - + } + len = PyString_GET_SIZE(str); - strncpy(buf, PyString_AsString(str), len); + if (len > buf_size) { + PyErr_Format(PyExc_ValueError, + "read() returned too much data: " + "%i bytes requested, %i returned", + buf_size, len); + Py_DECREF(str); + goto finally; + } + memcpy(buf, PyString_AsString(str), len); Py_XDECREF(str); finally: + Py_XDECREF(arg); return len; } @@ -512,14 +525,16 @@ xmlparse_ParseFile( xmlparseobject *self, PyObject *args ) if( fp ){ bytes_read=fread( buf, sizeof( char ), BUF_SIZE, fp); - }else{ + if (bytes_read < 0) { + PyErr_SetFromErrno(PyExc_IOError); + return NULL; + } + } else { bytes_read=readinst( buf, BUF_SIZE, readmethod ); + if (bytes_read < 0) + return NULL; } - if (bytes_read < 0) { - PyErr_SetFromErrno(PyExc_IOError); - return NULL; - } rv=XML_ParseBuffer(self->itself, bytes_read, bytes_read == 0); if( PyErr_Occurred() ){ return NULL; -- cgit v0.12