From e6e3eb5ee89ac4c163d46429391c889a1bb5e404 Mon Sep 17 00:00:00 2001 From: Yochai Eisenrich Date: Sun, 29 Mar 2026 00:14:36 +0300 Subject: [PATCH] net: sched: cls_api: fix tc_chain_fill_node to initialize tcm_info to zero to prevent an info-leak When building netlink messages, tc_chain_fill_node() never initializes the tcm_info field of struct tcmsg. Since the allocation is not zeroed, kernel heap memory is leaked to userspace through this 4-byte field. The fix simply zeroes tcm_info alongside the other fields that are already initialized. Fixes: 32a4f5ecd738 ("net: sched: introduce chain object to uapi") Signed-off-by: Yochai Eisenrich Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260328211436.1010152-1-echelonh@gmail.com Signed-off-by: Jakub Kicinski --- net/sched/cls_api.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 4829c27446e3..20f7f9ee0b35 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -2969,6 +2969,7 @@ static int tc_chain_fill_node(const struct tcf_proto_ops *tmplt_ops, tcm->tcm__pad1 = 0; tcm->tcm__pad2 = 0; tcm->tcm_handle = 0; + tcm->tcm_info = 0; if (block->q) { tcm->tcm_ifindex = qdisc_dev(block->q)->ifindex; tcm->tcm_parent = block->q->handle;