sch_dsmark: fix invalid skb_cow() usage (aea92fb2) · Commits · 戴 / test

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: ("[PKT_SCHED] dsmark: handle cloned and non-linear skb's") Signed-off-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

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))

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