xfrm: do pskb_pull properly in __xfrm_transport_prep
For transport mode, when ipv6 nexthdr is set, the packet format might
be like:
----------------------------------------------------
| | dest | | | | ESP | ESP |
| IP6 hdr| opts.| ESP | TCP | Data | Trailer | ICV |
----------------------------------------------------
and in __xfrm_transport_prep():
pskb_pull(skb, skb->mac_len + sizeof(ip6hdr) + x->props.header_len);
it will pull the data pointer to the wrong position, as it missed the
nexthdrs/dest opts.
This patch is to fix it by using:
pskb_pull(skb, skb_transport_offset(skb) + x->props.header_len);
as we can be sure transport_header points to ESP header at that moment.
It also fixes a panic when packets with ipv6 nexthdr are sent over
esp6 transport mode:
[ 100.473845] kernel BUG at net/core/skbuff.c:4325!
[ 100.478517] RIP: 0010:__skb_to_sgvec+0x252/0x260
[ 100.494355] Call Trace:
[ 100.494829] skb_to_sgvec+0x11/0x40
[ 100.495492] esp6_output_tail+0x12e/0x550 [esp6]
[ 100.496358] esp6_xmit+0x1d5/0x260 [esp6_offload]
[ 100.498029] validate_xmit_xfrm+0x22f/0x2e0
[ 100.499604] __dev_queue_xmit+0x589/0x910
[ 100.502928] ip6_finish_output2+0x2a5/0x5a0
[ 100.503718] ip6_output+0x6c/0x120
[ 100.505198] xfrm_output_resume+0x4bf/0x530
[ 100.508683] xfrm6_output+0x3a/0xc0
[ 100.513446] inet6_csk_xmit+0xa1/0xf0
[ 100.517335] tcp_sendmsg+0x27/0x40
[ 100.517977] sock_sendmsg+0x3e/0x60
[ 100.518648] __sys_sendto+0xee/0x160
Fixes: c35fe4106b92 ("xfrm: Add mode handlers for IPsec on layer 2")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
1 file changed
