diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 4748c2c404..b3b324b3e6 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -281,7 +281,7 @@ typedef struct {
 	guint          linklocal6_timeout_id;
 
 	char *         ip6_disable_ipv6_path;
-	gint           ip6_disable_ipv6_save;
+	gint32         ip6_disable_ipv6_save;
 
 	char *         ip6_accept_ra_path;
 	gint32         ip6_accept_ra_save;
@@ -441,16 +441,16 @@ save_ip6_properties (NMDevice *self)
 {
 	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
 
-	priv->ip6_accept_ra_save = nm_platform_sysctl_get_uint (priv->ip6_accept_ra_path);
-	if (priv->ip6_accept_ra_save > 2)
+	priv->ip6_accept_ra_save = nm_platform_sysctl_get_int32 (priv->ip6_accept_ra_path, -1);
+	if (priv->ip6_accept_ra_save > 2 || priv->ip6_accept_ra_save < -1)
 		priv->ip6_accept_ra_save = -1;
 
-	priv->ip6_use_tempaddr_save = nm_platform_sysctl_get_uint (priv->ip6_use_tempaddr_path);
-	if (priv->ip6_use_tempaddr_save > 2)
+	priv->ip6_use_tempaddr_save = nm_platform_sysctl_get_int32 (priv->ip6_use_tempaddr_path, -1);
+	if (priv->ip6_use_tempaddr_save > 2 || priv->ip6_use_tempaddr_save < -1)
 		priv->ip6_use_tempaddr_save = -1;
 
-	priv->ip6_disable_ipv6_save = nm_platform_sysctl_get_uint (priv->ip6_disable_ipv6_path);
-	if (priv->ip6_disable_ipv6_save > 1)
+	priv->ip6_disable_ipv6_save = nm_platform_sysctl_get_int32 (priv->ip6_disable_ipv6_path, -1);
+	if (priv->ip6_disable_ipv6_save > 1 || priv->ip6_disable_ipv6_save < -1)
 		priv->ip6_disable_ipv6_save = -1;
 }
 
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 7cb5a4dbe5..9a40d6770f 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -27,6 +27,7 @@
 #include <netlink/route/addr.h>
 
 #include "nm-platform.h"
+#include "NetworkManagerUtils.h"
 #include "nm-logging.h"
 #include "nm-enum-types.h"
 
@@ -244,27 +245,33 @@ nm_platform_sysctl_get (const char *path)
 }
 
 /**
- * nm_platform_sysctl_get_uint:
+ * nm_platform_sysctl_get_int32:
  * @path: Absolute path to sysctl
+ * @fallback: default value, if the content of path could not be read
+ * as decimal integer.
  *
- * Returns: (unsigned integer) contents of the sysctl file, or -1 on error
+ * Returns: contents of the sysctl file parsed as s32 integer, or
+ * @fallback on error. Also, on error, @errno will be set to a non-zero
+ * value.
  */
-int
-nm_platform_sysctl_get_uint (const char *path)
+gint32
+nm_platform_sysctl_get_int32 (const char *path, gint32 fallback)
 {
-	char *value, *end;
-	long tmp;
-	int ret = -1;
+	char *value = NULL;
+	gint32 ret;
 
-	value = nm_platform_sysctl_get (path);
-	if (!value)
-		return ret;
+	g_return_val_if_fail (path, fallback);
 
-	tmp = strtoul (value, &end, 10);
-	if (!*end)
-		ret = tmp;
+	if (path)
+		value = nm_platform_sysctl_get (path);
+
+	if (!value) {
+		errno = EINVAL;
+		return fallback;
+	}
+
+	ret = nm_utils_ascii_str_to_int64 (value, 10, G_MININT32, G_MAXINT32, fallback);
 	g_free (value);
-
 	return ret;
 }
 
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index b742c39670..0a5a599898 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -350,7 +350,7 @@ void nm_platform_query_devices (void);
 
 gboolean nm_platform_sysctl_set (const char *path, const char *value);
 char *nm_platform_sysctl_get (const char *path);
-int nm_platform_sysctl_get_uint (const char *path);
+gint32 nm_platform_sysctl_get_int32 (const char *path, gint32 fallback);
 
 GArray *nm_platform_link_get_all (void);
 gboolean nm_platform_dummy_add (const char *name);