From: Yochai Eisenrich <echelonh@gmail.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: Yochai Eisenrich <echelonh@gmail.com>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
security@kernel.org, netdev@vger.kernel.org
Subject: [PATCH] net: sched: cls_api: fix tc_chain_fill_node to initialize tcm_info to zero to prevent an info-leak
Date: Sun, 29 Mar 2026 00:14:36 +0300 [thread overview]
Message-ID: <20260328211436.1010152-1-echelonh@gmail.com> (raw)
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 <echelonh@gmail.com>
---
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;
--
2.53.0
next reply other threads:[~2026-03-28 21:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-28 21:14 Yochai Eisenrich [this message]
2026-03-29 12:16 ` [PATCH] net: sched: cls_api: fix tc_chain_fill_node to initialize tcm_info to zero to prevent an info-leak Jamal Hadi Salim
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