From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit aea92fb2e09e29653b023d4254ac9fbf94221538 ]
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: 4c30719f4f55 ("[PKT_SCHED] dsmark: handle cloned and non-linear skb's")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
net/sched/sch_dsmark.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index d0dff0cd8186..cce4e6ada7fa 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -199,9 +199,13 @@ 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))
@@ -209,7 +213,9 @@ 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))
--
2.11.0