From e047ca988f1858a6b91bda837b45a7c783a33295 Mon Sep 17 00:00:00 2001 From: Andrea Claudi Date: Tue, 1 Oct 2019 12:32:17 +0200 Subject: [PATCH] tc: fix segmentation fault on gact action tc segfaults if gact action is used without action or index: $ ip link add type dummy $ tc actions add action pipe index 1 $ tc filter add dev dummy0 parent ffff: protocol ip \ pref 10 u32 match ip src 127.0.0.2 flowid 1:10 action gact Segmentation fault We expect tc to fail gracefully with an error message. This happens if gact is the last argument of the incomplete command. In this case the "gact" action is parsed, the macro NEXT_ARG_FWD() is executed and the next matches() crashes because of null argv pointer. To avoid this, simply use NEXT_ARG() instead. With this change in place: $ ip link add type dummy $ tc actions add action pipe index 1 $ tc filter add dev dummy0 parent ffff: protocol ip \ pref 10 u32 match ip src 127.0.0.2 flowid 1:10 action gact Command line is not complete. Try option "help" Fixes: fa4958897314 ("tc: Fix binding of gact action by index.") Reported-by: Davide Caratti Signed-off-by: Andrea Claudi Signed-off-by: Stephen Hemminger --- tc/m_gact.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tc/m_gact.c b/tc/m_gact.c index dca2a2f9..b06e8ee9 100644 --- a/tc/m_gact.c +++ b/tc/m_gact.c @@ -87,7 +87,7 @@ parse_gact(struct action_util *a, int *argc_p, char ***argv_p, return -1; if (!matches(*argv, "gact")) - NEXT_ARG_FWD(); + NEXT_ARG(); /* we're binding existing gact action to filter by index. */ if (!matches(*argv, "index")) goto skip_args;