[PATCH v3] interface: fix udev_device_get_sysattr_value return value check
Reviewing the code I found that return value of function
udev_device_get_sysattr_value() is dereferenced without a check.
udev_device_get_sysattr_value() may return NULL by number of reasons.
v2: VIR_DEBUG added, replaced STREQ(NULLSTR()) with STREQ_NULLABLE()
v3: More checks added, to skip earlier. More verbose VIR_DEBUG.
Signed-off-by: Dmitry Frolov <frolov(a)swemel.ru>
---
src/interface/interface_backend_udev.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/src/interface/interface_backend_udev.c
b/src/interface/interface_backend_udev.c
index a0485ddd21..fb6799ed94 100644
--- a/src/interface/interface_backend_udev.c
+++ b/src/interface/interface_backend_udev.c
@@ -23,6 +23,7 @@
#include <dirent.h>
#include <libudev.h>
+#include "virlog.h"
#include "virerror.h"
#include "virfile.h"
#include "datatypes.h"
@@ -40,6 +41,8 @@
#define VIR_FROM_THIS VIR_FROM_INTERFACE
+VIR_LOG_INIT("interface.interface_backend_udev");
+
struct udev_iface_driver {
struct udev *udev;
/* pid file FD, ensures two copies of the driver can't use the same root */
@@ -354,11 +357,20 @@ udevConnectListAllInterfaces(virConnectPtr conn,
const char *macaddr;
g_autoptr(virInterfaceDef) def = NULL;
- path = udev_list_entry_get_name(dev_entry);
- dev = udev_device_new_from_syspath(udev, path);
- name = udev_device_get_sysname(dev);
+ if (!(path = udev_list_entry_get_name(dev_entry))) {
+ VIR_DEBUG("Skipping interface, path == NULL");
+ continue;
+ }
+ if (!(dev = udev_device_new_from_syspath(udev, path))) {
+ VIR_DEBUG("Skipping interface '%s', dev == NULL", path);
+ continue;
+ }
+ if (!(name = udev_device_get_sysname(dev))) {
+ VIR_DEBUG("Skipping interface '%s', name == NULL", path);
+ continue;
+ }
macaddr = udev_device_get_sysattr_value(dev, "address");
- status = STREQ(udev_device_get_sysattr_value(dev, "operstate"),
"up");
+ status = STREQ_NULLABLE(udev_device_get_sysattr_value(dev,
"operstate"), "up");
def = udevGetMinimalDefForDevice(dev);
if (!virConnectListAllInterfacesCheckACL(conn, def)) {
@@ -964,9 +976,9 @@ udevGetIfaceDef(struct udev *udev, const char *name)
/* MTU */
mtu_str = udev_device_get_sysattr_value(dev, "mtu");
- if (virStrToLong_ui(mtu_str, NULL, 10, &mtu) < 0) {
+ if (!mtu_str || virStrToLong_ui(mtu_str, NULL, 10, &mtu) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
- _("Could not parse MTU value '%1$s'"), mtu_str);
+ _("Could not parse MTU value '%1$s'"),
NULLSTR(mtu_str));
goto error;
}
ifacedef->mtu = mtu;
@@ -1089,7 +1101,7 @@ udevInterfaceIsActive(virInterfacePtr ifinfo)
goto cleanup;
/* Check if it's active or not */
- status = STREQ(udev_device_get_sysattr_value(dev, "operstate"),
"up");
+ status = STREQ_NULLABLE(udev_device_get_sysattr_value(dev, "operstate"),
"up");
udev_device_unref(dev);
--
2.34.1