[LTP] [PATCH v2 2/2] tcindex01: Simplify test

[Martin Doucha]

The bug can be reproduced simply by adding, removing and adding again
the same tcindex traffic filter. If the bug is present, the attempt
to add the removed filter again will fail with EEXIST error.

Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---

Changes since v1: Call tst_netdev_add_traffic_filter() in non-strict mode
and report meaningful results according to return/errno value.

 testcases/cve/tcindex01.c | 45 +++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/testcases/cve/tcindex01.c b/testcases/cve/tcindex01.c
index 9bd7de9dd..91bfafb53 100644
--- a/testcases/cve/tcindex01.c
+++ b/testcases/cve/tcindex01.c
@@ -84,31 +84,26 @@ static void setup(void)
 
 static void run(void)
 {
-	unsigned int i;
-
-	for (i = 0; i < 100; i++) {
-		NETDEV_ADD_QDISC(DEVNAME, AF_UNSPEC, TC_H_ROOT, qd_handle,
-			"htb", qd_config);
-		NETDEV_ADD_TRAFFIC_CLASS(DEVNAME, qd_handle, clsid, "htb",
-			cls_config);
-		NETDEV_ADD_TRAFFIC_FILTER(DEVNAME, qd_handle, 10, ETH_P_IP, 1,
-			"tcindex", f_config);
-		NETDEV_REMOVE_TRAFFIC_FILTER(DEVNAME, qd_handle, 10, ETH_P_IP,
-			1, "tcindex");
-
-		/* Wait at least one jiffy for use-after-free */
-		usleep(10000);
-
-		NETDEV_REMOVE_QDISC(DEVNAME, AF_UNSPEC, TC_H_ROOT, qd_handle,
-			"htb");
-	}
-
-	if (tst_taint_check()) {
-		tst_res(TFAIL, "Kernel is vulnerable");
-		return;
-	}
-
-	tst_res(TPASS, "Nothing bad happened (yet)");
+	int ret;
+
+	NETDEV_ADD_QDISC(DEVNAME, AF_UNSPEC, TC_H_ROOT, qd_handle, "htb",
+		qd_config);
+	NETDEV_ADD_TRAFFIC_CLASS(DEVNAME, qd_handle, clsid, "htb", cls_config);
+	NETDEV_ADD_TRAFFIC_FILTER(DEVNAME, qd_handle, 10, ETH_P_IP, 1,
+		"tcindex", f_config);
+	NETDEV_REMOVE_TRAFFIC_FILTER(DEVNAME, qd_handle, 10, ETH_P_IP,
+		1, "tcindex");
+	ret = tst_netdev_add_traffic_filter(__FILE__, __LINE__, 0, DEVNAME,
+		qd_handle, 10, ETH_P_IP, 1, "tcindex", f_config);
+	TST_ERR = tst_rtnl_errno;
+	NETDEV_REMOVE_QDISC(DEVNAME, AF_UNSPEC, TC_H_ROOT, qd_handle, "htb");
+
+	if (ret)
+		tst_res(TPASS, "Removing tcindex filter works correctly");
+	else if (TST_ERR == EEXIST)
+		tst_res(TFAIL, "Kernel traffic filter list is corrupted");
+	else
+		tst_brk(TBROK | TTERRNO, "Unexpected rtnetlink error");
 }
 
 static void cleanup(void)
-- 
2.42.0