[PATCH v3 1/2] net: sched: act_connmark: initialize struct tc_ife to fix kernel leak
From: Ranganath V N <hidden>
Date: 2025-11-06 19:57:03
Also in:
lkml
Subsystem:
networking [general], tc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
In tcf_connmark_dump(), the variable 'opt' was partially initialized using a designatied initializer. While the padding bytes are reamined uninitialized. nla_put() copies the entire structure into a netlink message, these uninitialized bytes leaked to userspace. Initialize the structure with memset before assigning its fields to ensure all members and padding are cleared prior to beign copied. Signed-off-by: Ranganath V N <redacted> --- net/sched/act_connmark.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index 3e89927d7116..2aaaaee9b6bb 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c@@ -195,13 +195,15 @@ static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a, const struct tcf_connmark_info *ci = to_connmark(a); unsigned char *b = skb_tail_pointer(skb); const struct tcf_connmark_parms *parms; - struct tc_connmark opt = { - .index = ci->tcf_index, - .refcnt = refcount_read(&ci->tcf_refcnt) - ref, - .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind, - }; + struct tc_connmark opt; struct tcf_t t; + memset(&opt, 0, sizeof(opt)); + + index = ci->tcf_index; + refcnt = refcount_read(&ci->tcf_refcnt) - ref; + bindcnt = atomic_read(&ci->tcf_bindcnt) - bind; + rcu_read_lock(); parms = rcu_dereference(ci->parms);
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2.43.0