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Commit 4319cc0c authored by Fernando Luis Vazquez Cao's avatar Fernando Luis Vazquez Cao Committed by Pablo Neira Ayuso
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netfilter: IPv6: initialize TOS field in REJECT target module 



The IPv6 header is not zeroed out in alloc_skb so we must initialize
it properly unless we want to see IPv6 packets with random TOS fields
floating around. The current implementation resets the flow label
but this could be changed if deemed necessary.

We stumbled upon this issue when trying to apply a mangle rule to
the RST packet generated by the REJECT target module.

Signed-off-by: default avatarFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 7a4f0761

net/ipv6/netfilter/ip6t_REJECT.c

+3 −1
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ static void send_reset(struct net *net, struct sk_buff *oldskb) 
	int tcphoff, needs_ack;

	const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);

	struct ipv6hdr *ip6h;

#define DEFAULT_TOS_VALUE	0x0U

	const __u8 tclass = DEFAULT_TOS_VALUE;

	struct dst_entry *dst = NULL;

	u8 proto;

	struct flowi6 fl6;
@@ -124,7 +126,7 @@ static void send_reset(struct net *net, struct sk_buff *oldskb) 
	skb_put(nskb, sizeof(struct ipv6hdr));

	skb_reset_network_header(nskb);

	ip6h = ipv6_hdr(nskb);

	ip6h->version = 6;

	*(__be32 *)ip6h =  htonl(0x60000000 | (tclass << 20));

	ip6h->hop_limit = ip6_dst_hoplimit(dst);

	ip6h->nexthdr = IPPROTO_TCP;

	ipv6_addr_copy(&ip6h->saddr, &oip6h->daddr);