Re: [PATCH v2,net-next] ip6_gre: fix a pontential issue in ip6erspan_rcv

[Haishuang Yan]

> On 2017年12月19日, at 下午11:34, David Miller  wrote:
> 
> From: Haishuang Yan 
> Date: Sat, 16 Dec 2017 10:25:25 +0800
> 
>> pskb_may_pull() can change skb->data, so we need to load ipv6h/ershdr at
>> the right place.
>> 
>> Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
>> Acked-by: William Tu 
>> Cc: William Tu 
>> Signed-off-by: Haishuang Yan 
> 
> This patch does not apply:
> 
>> +ipv6h = ipv6_hdr(skb);
>> +ershdr = (struct erspan_base_hdr *)skb->data;
>>  ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
>>  tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
>>  pkt_md = (struct erspan_metadata *)(ershdr + 1);
> 
> There is not "pkt_md = ..." assignment in net-next on this line.
> 

Okay, I will fix it and resubmit another commit, thanks.

Re: [PATCH v2,net-next] ip6_gre: fix a pontential issue in ip6erspan_rcv

[David Miller]

From: Haishuang Yan 
Date: Sat, 16 Dec 2017 10:25:25 +0800

> pskb_may_pull() can change skb->data, so we need to load ipv6h/ershdr at
> the right place.
> 
> Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
> Acked-by: William Tu 
> Cc: William Tu 
> Signed-off-by: Haishuang Yan 

This patch does not apply:

> + ipv6h = ipv6_hdr(skb);
> + ershdr = (struct erspan_base_hdr *)skb->data;
>   ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
>   tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
>   pkt_md = (struct erspan_metadata *)(ershdr + 1);

There is not "pkt_md = ..." assignment in net-next on this line.

[PATCH v2,net-next] ip6_gre: fix a pontential issue in ip6erspan_rcv

[Haishuang Yan]

pskb_may_pull() can change skb->data, so we need to load ipv6h/ershdr at
the right place.

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Acked-by: William Tu 
Cc: William Tu 
Signed-off-by: Haishuang Yan 

---
Change since v2:
  * Rebase on latest master.
---
 net/ipv6/ip6_gre.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index f210f9c..aa1512e 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -507,12 +507,11 @@ static int ip6erspan_rcv(struct sk_buff *skb, int 
gre_hdr_len,
struct ip6_tnl *tunnel;
u8 ver;
 
-   ipv6h = ipv6_hdr(skb);
-   ershdr = (struct erspan_base_hdr *)skb->data;
-
if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr
return PACKET_REJECT;
 
+   ipv6h = ipv6_hdr(skb);
+   ershdr = (struct erspan_base_hdr *)skb->data;
ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
pkt_md = (struct erspan_metadata *)(ershdr + 1);
-- 
1.8.3.1