Commit 7d9dbdfb authored by Menglong Dong's avatar Menglong Dong Committed by David S. Miller
Browse files

net: ipv6: add skb drop reasons to TLV parse 



Replace kfree_skb() used in TLV encoded option header parsing with
kfree_skb_reason(). Following functions are involved:

ip6_parse_tlv()
ipv6_hop_ra()
ipv6_hop_ioam()
ipv6_hop_jumbo()
ipv6_hop_calipso()
ipv6_dest_hao()

Most skb drops during this process are regarded as 'InHdrErrors',
as 'IPSTATS_MIB_INHDRERRORS' is used when ip6_parse_tlv() fails,
which make we use 'SKB_DROP_REASON_IP_INHDR' correspondingly.

However, 'IP_INHDR' is a relatively general reason. Therefore, we
can use other reasons with higher priority in some cases. For example,
'SKB_DROP_REASON_UNHANDLED_PROTO' is used for unknown TLV options.

Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Reviewed-by: default avatarJiang Biao <benbjiang@tencent.com>
Reviewed-by: default avatarHao Peng <flyingpeng@tencent.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bba98083

net/ipv6/exthdrs.c

+24 −12
Original line number Diff line number Diff line
@@ -90,12 +90,13 @@ static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff, 
			break;

		fallthrough;

	case 2: /* send ICMP PARM PROB regardless and drop packet */

		icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);

		icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff,

					 SKB_DROP_REASON_UNHANDLED_PROTO);

		return false;

	}



drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);

	return false;

}
@@ -218,7 +219,7 @@ static bool ip6_parse_tlv(bool hopbyhop, 
	if (len == 0)

		return true;

bad:

	kfree_skb(skb);

	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);

	return false;

}
@@ -232,6 +233,7 @@ static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 
	struct ipv6_destopt_hao *hao;

	struct inet6_skb_parm *opt = IP6CB(skb);

	struct ipv6hdr *ipv6h = ipv6_hdr(skb);

	SKB_DR(reason);

	int ret;



	if (opt->dsthao) {
@@ -246,19 +248,23 @@ static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 
	if (hao->length != 16) {

		net_dbg_ratelimited("hao invalid option length = %d\n",

				    hao->length);

		SKB_DR_SET(reason, IP_INHDR);

		goto discard;

	}



	if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {

		net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",

				    &hao->addr);

		SKB_DR_SET(reason, INVALID_PROTO);

		goto discard;

	}



	ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,

			       (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);

	if (unlikely(ret < 0))

	if (unlikely(ret < 0)) {

		SKB_DR_SET(reason, XFRM_POLICY);

		goto discard;

	}



	if (skb_cloned(skb)) {

		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
@@ -281,7 +287,7 @@ static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 
	return true;



 discard:

	kfree_skb(skb);

	kfree_skb_reason(skb, reason);

	return false;

}

#endif
@@ -931,7 +937,7 @@ static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 
	}

	net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",

			    nh[optoff + 1]);

	kfree_skb(skb);

	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);

	return false;

}
@@ -985,7 +991,7 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 
	return true;



drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);

	return false;

}
@@ -994,26 +1000,32 @@ static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 
static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)

{

	const unsigned char *nh = skb_network_header(skb);

	SKB_DR(reason);

	u32 pkt_len;



	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {

		net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",

				    nh[optoff+1]);

		SKB_DR_SET(reason, IP_INHDR);

		goto drop;

	}



	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));

	if (pkt_len <= IPV6_MAXPLEN) {

		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);

		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,

					 SKB_DROP_REASON_IP_INHDR);

		return false;

	}

	if (ipv6_hdr(skb)->payload_len) {

		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);

		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,

					 SKB_DROP_REASON_IP_INHDR);

		return false;

	}



	if (pkt_len > skb->len - sizeof(struct ipv6hdr))

	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {

		SKB_DR_SET(reason, PKT_TOO_SMALL);

		goto drop;

	}



	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))

		goto drop;
@@ -1022,7 +1034,7 @@ static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 
	return true;



drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, reason);

	return false;

}
@@ -1044,7 +1056,7 @@ static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 
	return true;



drop:

	kfree_skb(skb);

	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);

	return false;

}