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Message-Id: <1467815048-2240-12-git-send-email-pablo@netfilter.org> Date: Wed, 6 Jul 2016 16:23:53 +0200 From: Pablo Neira Ayuso <pablo@...filter.org> To: netfilter-devel@...r.kernel.org Cc: davem@...emloft.net, netdev@...r.kernel.org Subject: [PATCH 11/26] netfilter: nf_reject_ipv4: don't send tcp RST if the packet is non-TCP From: Liping Zhang <liping.zhang@...eadtrum.com> In iptables, if the user add a rule to send tcp RST and specify the non-TCP protocol, such as UDP, kernel will reject this request. But in nftables, this validity check only occurs in nft tool, i.e. only in userspace. This means that user can add such a rule like follows via nfnetlink: "nft add rule filter forward ip protocol udp reject with tcp reset" This will generate some confusing tcp RST packets. So we should send tcp RST only when it is TCP packet. Signed-off-by: Liping Zhang <liping.zhang@...eadtrum.com> Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org> --- net/ipv4/netfilter/nf_reject_ipv4.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index b6ea57e..fd82202 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -24,6 +24,9 @@ const struct tcphdr *nf_reject_ip_tcphdr_get(struct sk_buff *oldskb, if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET)) return NULL; + if (ip_hdr(oldskb)->protocol != IPPROTO_TCP) + return NULL; + oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb), sizeof(struct tcphdr), _oth); if (oth == NULL) -- 2.1.4
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