From: Xin Long lucien.xin@gmail.com
commit 06a0afcfe2f551ff755849ea2549b0d8409fd9a0 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/xfrm/xfrm_device.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/net/xfrm/xfrm_device.c +++ b/net/xfrm/xfrm_device.c @@ -25,12 +25,10 @@ static void __xfrm_transport_prep(struct struct xfrm_offload *xo = xfrm_offload(skb);
skb_reset_mac_len(skb); - pskb_pull(skb, skb->mac_len + hsize + x->props.header_len); - - if (xo->flags & XFRM_GSO_SEGMENT) { - skb_reset_transport_header(skb); + if (xo->flags & XFRM_GSO_SEGMENT) skb->transport_header -= x->props.header_len; - } + + pskb_pull(skb, skb_transport_offset(skb) + x->props.header_len); }
static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,