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Commit aea92fb2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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sch_dsmark: fix invalid skb_cow() usage 



skb_cow(skb, sizeof(ip header)) is not very helpful in this context.

First we need to use pskb_may_pull() to make sure the ip header
is in skb linear part, then use skb_try_make_writable() to
address clones issues.

Fixes: 4c30719f ("[PKT_SCHED] dsmark: handle cloned and non-linear skb's")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 09050957

net/sched/sch_dsmark.c

+8 −2
Original line number Diff line number Diff line
@@ -201,9 +201,13 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
	pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);



	if (p->set_tc_index) {

		int wlen = skb_network_offset(skb);



		switch (tc_skb_protocol(skb)) {

		case htons(ETH_P_IP):

			if (skb_cow_head(skb, sizeof(struct iphdr)))

			wlen += sizeof(struct iphdr);

			if (!pskb_may_pull(skb, wlen) ||

			    skb_try_make_writable(skb, wlen))

				goto drop;



			skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
@@ -211,7 +215,9 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
			break;



		case htons(ETH_P_IPV6):

			if (skb_cow_head(skb, sizeof(struct ipv6hdr)))

			wlen += sizeof(struct ipv6hdr);

			if (!pskb_may_pull(skb, wlen) ||

			    skb_try_make_writable(skb, wlen))

				goto drop;



			skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))