From d02c9acd68950a444acda18d514e2b41f846cb7f Mon Sep 17 00:00:00 2001 From: Jun Yang Date: Wed, 5 Mar 2025 23:44:10 +0800 Subject: [PATCH] sched: address a potential NULL pointer dereference in the GRED scheduler. [ Upstream commit 115ef44a98220fddfab37a39a19370497cd718b9 ] If kzalloc in gred_init returns a NULL pointer, the code follows the error handling path, invoking gred_destroy. This, in turn, calls gred_offload, where memset could receive a NULL pointer as input, potentially leading to a kernel crash. When table->opt is NULL in gred_init(), gred_change_table_def() is not called yet, so it is not necessary to call ->ndo_setup_tc() in gred_offload(). Signed-off-by: Jun Yang Reviewed-by: Cong Wang Fixes: f25c0515c521 ("net: sched: gred: dynamically allocate tc_gred_qopt_offload") Link: https://patch.msgid.link/20250305154410.3505642-1-juny24602@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_gred.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c index 872d127c9db4..fa7a1b69c0f3 100644 --- a/net/sched/sch_gred.c +++ b/net/sched/sch_gred.c @@ -913,7 +913,8 @@ static void gred_destroy(struct Qdisc *sch) for (i = 0; i < table->DPs; i++) gred_destroy_vq(table->tab[i]); - gred_offload(sch, TC_GRED_DESTROY); + if (table->opt) + gred_offload(sch, TC_GRED_DESTROY); kfree(table->opt); }