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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Florian Westphal <fw@strlen.de>,
        Taehee Yoo <ap420073@gmail.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>
Subject: [PATCH 4.17 43/46] netfilter: nf_tables: use WARN_ON_ONCE instead of BUG_ON in nft_do_chain()
Date:   Fri,  6 Jul 2018 07:47:04 +0200
Message-Id: <20180706054526.754434739@linuxfoundation.org>
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4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Taehee Yoo <ap420073@gmail.com>

commit adc972c5b88829d38ede08b1069718661c7330ae upstream.

When depth of chain is bigger than NFT_JUMP_STACK_SIZE, the nft_do_chain
crashes. But there is no need to crash hard here.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/netfilter/nf_tables_core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -208,7 +208,8 @@ next_rule:
 
 	switch (regs.verdict.code) {
 	case NFT_JUMP:
-		BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
+		if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
+			return NF_DROP;
 		jumpstack[stackptr].chain = chain;
 		jumpstack[stackptr].rule  = rule;
 		jumpstack[stackptr].rulenum = rulenum;