Fixed several memory leaks

Several places python-ethtool leaked memory, mostly due to missing
Py_DECREF() calls on objects being put in to python lists (via
PyList_Append() calls).

This revealed an issue in addition where the IPv6 addresses pointers
in some cases could freed more times.  This is fixed as well.

Signed-off-by: David Sommerseth <davids@redhat.com>

Author: David Sommerseth

python-ethtool/etherinfo.c

@@ -59,16 +59,14 @@
 void free_ipv6addresses(struct ipv6address *ptr) {
 	struct ipv6address *ipv6ptr = ptr;
 
-	if( !ptr ) {
-		return;
-	}
-
 	while( ipv6ptr ) {
 		struct ipv6address *tmp = ipv6ptr->next;
 
 		if( ipv6ptr->address ) {
 			free(ipv6ptr->address);
+			ipv6ptr->address = NULL;
 		}
+		memset(ipv6ptr, 0, sizeof(struct ipv6address));
 		free(ipv6ptr);
 		ipv6ptr = tmp;
 	}

python-ethtool/etherinfo_obj.c

@@ -167,33 +167,37 @@ PyObject *_ethtool_etherinfo_str(etherinfo_py *self)
 	if( self->data->ethinfo->hwaddress ) {
 		PyObject *tmp = PyString_FromFormat("\tMAC address: %s\n", self->data->ethinfo->hwaddress);
 		PyString_Concat(&ret, tmp);
+		Py_DECREF(tmp);
 	}
 
 	if( self->data->ethinfo->ipv4_address ) {
 		PyObject *tmp = PyString_FromFormat("\tIPv4 address: %s/%i",
 						   self->data->ethinfo->ipv4_address,
 						   self->data->ethinfo->ipv4_netmask);
 		if( self->data->ethinfo->ipv4_broadcast ) {
-			PyObject *tmp2 = PyString_FromFormat("    Broadcast: %s",
+			PyObject *tmp2 = PyString_FromFormat("	  Broadcast: %s",
 							     self->data->ethinfo->ipv4_broadcast);
 			PyString_Concat(&tmp, tmp2);
+			Py_DECREF(tmp2);
 		}
 		PyString_Concat(&tmp, PyString_FromString("\n"));
 		PyString_Concat(&ret, tmp);
+		Py_DECREF(tmp);
 	}
 
 	if( self->data->ethinfo->ipv6_addresses ) {
 		struct ipv6address *ipv6 = self->data->ethinfo->ipv6_addresses;
 		PyObject *tmp = PyString_FromFormat("\tIPv6 addresses:\n");
 		PyString_Concat(&ret, tmp);
-
+		Py_DECREF(tmp);
 		for( ; ipv6; ipv6 = ipv6->next) {
 			char scope[66];
 
 			rtnl_scope2str(ipv6->scope, scope, 64);
 			PyObject *addr = PyString_FromFormat("\t		[%s] %s/%i\n",
 							     scope, ipv6->address, ipv6->netmask);
 			PyString_Concat(&ret, addr);
+			Py_DECREF(addr);
 		}
 	}
 	return ret;
@@ -249,10 +253,10 @@ PyObject * _ethtool_etherinfo_get_ipv6_addresses(etherinfo_py *self, PyObject *n
 		}
 		PyTuple_SetItem(args, 0, ipv6_pydata);
 		ipv6_pyobj = PyObject_CallObject((PyObject *)&ethtool_etherinfoIPv6Type, args);
+		Py_DECREF(args);
 		if( ipv6_pyobj ) {
 			PyTuple_SetItem(ret, i++, ipv6_pyobj);
 			_PyTuple_Resize(&ret, i+1);
-			Py_INCREF(ipv6_pyobj);
 		} else {
 			PyErr_SetString(PyExc_RuntimeError,
 					"[INTERNAL] Failed to initialise the new "
@@ -262,6 +266,7 @@ PyObject * _ethtool_etherinfo_get_ipv6_addresses(etherinfo_py *self, PyObject *n
 		ipv6 = next;
 	}
 	_PyTuple_Resize(&ret, i);
+	self->data->ethinfo->ipv6_addresses = NULL;
 	return ret;
 }
 

python-ethtool/ethtool.c

@@ -93,8 +93,11 @@ static PyObject *get_active_devices(PyObject *self __unused, PyObject *args __un
 	ifr = ifc.ifc_req;
 	for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
 		if (!(ioctl(skfd, SIOCGIFFLAGS, ifr) < 0))
-			if (ifr->ifr_flags & IFF_UP)
-				PyList_Append(list, PyString_FromString(ifr->ifr_name));
+			if (ifr->ifr_flags & IFF_UP) {
+				PyObject *str = PyString_FromString(ifr->ifr_name);
+				PyList_Append(list, str);
+				Py_DECREF(str);
+			}
 			ifr++;
 	}
 
@@ -118,6 +121,7 @@ static PyObject *get_devices(PyObject *self __unused, PyObject *args __unused)
 	/* skip over first two lines */
 	ret = fgets(buffer, 256, fd); ret = fgets(buffer, 256, fd);
 	while (!feof(fd)) {
+		PyObject *str;
 		char *name = buffer;
 		char *end = buffer;
 
@@ -129,7 +133,10 @@ static PyObject *get_devices(PyObject *self __unused, PyObject *args __unused)
 		*end = 0; /* terminate where colon was */
 		while (*name == ' ')
 			name++; /* skip over leading whitespace if any */
-		PyList_Append(list, PyString_FromString(name));
+
+		str = PyString_FromString(name);
+		PyList_Append(list, str);
+		Py_DECREF(str);
 	}
 	fclose(fd);
 	return list;
@@ -320,7 +327,9 @@ static PyObject *get_interfaces_info(PyObject *self __unused, PyObject *args) {
 			PyObject *dev = PyObject_CallObject((PyObject *)&ethtool_etherinfoType, args);
 			if( dev ) {
 				PyList_Append(devlist, dev);
+				Py_DECREF(dev);
 			}
+			Py_DECREF(args);
 		}
 	}
 	if( fetch_devs_len > 0 ) {