From: Ranganath V N Date: Sun, 9 Nov 2025 09:13:35 +0000 (+0530) Subject: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak X-Git-Tag: v6.18-rc6~31^2~10^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=62b656e43eaeae445a39cd8021a4f47065af4389;p=thirdparty%2Fkernel%2Flinux.git net: sched: act_connmark: initialize struct tc_ife to fix kernel leak 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. Reported-by: syzbot+0c85cae3350b7d486aee@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c85cae3350b7d486aee Tested-by: syzbot+0c85cae3350b7d486aee@syzkaller.appspotmail.com Fixes: 22a5dc0e5e3e ("net: sched: Introduce connmark action") Signed-off-by: Ranganath V N Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251109091336.9277-2-vnranganath.20@gmail.com Acked-by: Cong Wang Signed-off-by: Paolo Abeni --- diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c index 3e89927d7116..26ba8c2d20ab 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)); + + opt.index = ci->tcf_index; + opt.refcnt = refcount_read(&ci->tcf_refcnt) - ref; + opt.bindcnt = atomic_read(&ci->tcf_bindcnt) - bind; + rcu_read_lock(); parms = rcu_dereference(ci->parms);