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net: sched: act_connmark: initialize struct tc_ife to fix kernel leak

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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 <vnranganath.20@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251109091336.9277-2-vnranganath.20@gmail.com
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Ranganath V N 2025-11-09 14:43:35 +05:30 committed by Paolo Abeni
parent 60e6489f8e
commit 62b656e43e
1 changed files with 7 additions and 5 deletions
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12
net/sched/act_connmark.c
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@ -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);