| From foo@baz Thu Dec 21 09:02:40 CET 2017 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Fri, 17 Mar 2017 08:05:28 -0700 |
| Subject: sch_dsmark: fix invalid skb_cow() usage |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| |
| [ 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@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <alexander.levin@verizon.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sched/sch_dsmark.c | 10 ++++++++-- |
| 1 file changed, 8 insertions(+), 2 deletions(-) |
| |
| --- a/net/sched/sch_dsmark.c |
| +++ b/net/sched/sch_dsmark.c |
| @@ -200,9 +200,13 @@ static int dsmark_enqueue(struct sk_buff |
| 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)) |
| @@ -210,7 +214,9 @@ static int dsmark_enqueue(struct sk_buff |
| 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)) |
