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Commit 5460d62d authored by Cong Wang's avatar Cong Wang Committed by Greg Kroah-Hartman
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netfilter: clear skb->next in NF_HOOK_LIST() 



NF_HOOK_LIST() uses list_del() to remove skb from the linked list,
however, it is not sufficient as skb->next still points to other
skb. We should just call skb_list_del_init() to clear skb->next,
like the rest places which using skb list.

This has been fixed in upstream by commit ca58fbe06c54
("netfilter: add and use nf_hook_slow_list()").

Fixes: 9f17dbf0 ("netfilter: fix use-after-free in NF_HOOK_LIST")
Reported-by: default avatar <liuzx@knownsec.com>
Tested-by: default avatar <liuzx@knownsec.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Edward Cree <ecree@solarflare.com>
Cc: stable@vger.kernel.org # between 4.19 and 5.4
Signed-off-by: default avatarCong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 98c9afed

include/linux/netfilter.h

+1 −1
Original line number Diff line number Diff line
@@ -300,7 +300,7 @@ NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 


	INIT_LIST_HEAD(&sublist);

	list_for_each_entry_safe(skb, next, head, list) {

		list_del(&skb->list);

		skb_list_del_init(skb);

		if (nf_hook(pf, hook, net, sk, skb, in, out, okfn) == 1)

			list_add_tail(&skb->list, &sublist);

	}