* [PATCH] vti: fix NULL dereference in xfrm_input()
@ 2017-09-12 11:53 Alexey Kodanev
2017-09-13 10:44 ` Steffen Klassert
0 siblings, 1 reply; 2+ messages in thread
From: Alexey Kodanev @ 2017-09-12 11:53 UTC (permalink / raw)
To: netdev; +Cc: Steffen Klassert, Herbert Xu, David Miller, Alexey Kodanev
Can be reproduced with LTP tests:
# icmp-uni-vti.sh -p ah -a sha256 -m tunnel -S fffffffe -k 1 -s 10
IPv4:
RIP: 0010:xfrm_input+0x7f9/0x870
...
Call Trace:
<IRQ>
vti_input+0xaa/0x110 [ip_vti]
? skb_free_head+0x21/0x40
vti_rcv+0x33/0x40 [ip_vti]
xfrm4_ah_rcv+0x33/0x60
ip_local_deliver_finish+0x94/0x1e0
ip_local_deliver+0x6f/0xe0
? ip_route_input_noref+0x28/0x50
...
# icmp-uni-vti.sh -6 -p ah -a sha256 -m tunnel -S fffffffe -k 1 -s 10
IPv6:
RIP: 0010:xfrm_input+0x7f9/0x870
...
Call Trace:
<IRQ>
xfrm6_rcv_tnl+0x3c/0x40
vti6_rcv+0xd5/0xe0 [ip6_vti]
xfrm6_ah_rcv+0x33/0x60
ip6_input_finish+0xee/0x460
ip6_input+0x3f/0xb0
ip6_rcv_finish+0x45/0xa0
ipv6_rcv+0x34b/0x540
xfrm_input() invokes xfrm_rcv_cb() -> vti_rcv_cb(), the last callback
might call skb_scrub_packet(), which in turn can reset secpath.
Fix it by adding a check that skb->sp is not NULL.
Fixes: 7e9e9202bccc ("xfrm: Clear RX SKB secpath xfrm_offload")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
---
net/xfrm/xfrm_input.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 2515cd2..8ac9d32 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -429,7 +429,8 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
nf_reset(skb);
if (decaps) {
- skb->sp->olen = 0;
+ if (skb->sp)
+ skb->sp->olen = 0;
skb_dst_drop(skb);
gro_cells_receive(&gro_cells, skb);
return 0;
@@ -440,7 +441,8 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
err = x->inner_mode->afinfo->transport_finish(skb, xfrm_gro || async);
if (xfrm_gro) {
- skb->sp->olen = 0;
+ if (skb->sp)
+ skb->sp->olen = 0;
skb_dst_drop(skb);
gro_cells_receive(&gro_cells, skb);
return err;
--
1.7.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] vti: fix NULL dereference in xfrm_input()
2017-09-12 11:53 [PATCH] vti: fix NULL dereference in xfrm_input() Alexey Kodanev
@ 2017-09-13 10:44 ` Steffen Klassert
0 siblings, 0 replies; 2+ messages in thread
From: Steffen Klassert @ 2017-09-13 10:44 UTC (permalink / raw)
To: Alexey Kodanev; +Cc: netdev, Herbert Xu, David Miller
On Tue, Sep 12, 2017 at 02:53:46PM +0300, Alexey Kodanev wrote:
> Can be reproduced with LTP tests:
> # icmp-uni-vti.sh -p ah -a sha256 -m tunnel -S fffffffe -k 1 -s 10
>
> IPv4:
> RIP: 0010:xfrm_input+0x7f9/0x870
> ...
> Call Trace:
> <IRQ>
> vti_input+0xaa/0x110 [ip_vti]
> ? skb_free_head+0x21/0x40
> vti_rcv+0x33/0x40 [ip_vti]
> xfrm4_ah_rcv+0x33/0x60
> ip_local_deliver_finish+0x94/0x1e0
> ip_local_deliver+0x6f/0xe0
> ? ip_route_input_noref+0x28/0x50
> ...
>
> # icmp-uni-vti.sh -6 -p ah -a sha256 -m tunnel -S fffffffe -k 1 -s 10
> IPv6:
> RIP: 0010:xfrm_input+0x7f9/0x870
> ...
> Call Trace:
> <IRQ>
> xfrm6_rcv_tnl+0x3c/0x40
> vti6_rcv+0xd5/0xe0 [ip6_vti]
> xfrm6_ah_rcv+0x33/0x60
> ip6_input_finish+0xee/0x460
> ip6_input+0x3f/0xb0
> ip6_rcv_finish+0x45/0xa0
> ipv6_rcv+0x34b/0x540
>
> xfrm_input() invokes xfrm_rcv_cb() -> vti_rcv_cb(), the last callback
> might call skb_scrub_packet(), which in turn can reset secpath.
>
> Fix it by adding a check that skb->sp is not NULL.
>
> Fixes: 7e9e9202bccc ("xfrm: Clear RX SKB secpath xfrm_offload")
> Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Patch applied, thanks Alexey!
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-09-13 10:44 ` Steffen Klassert
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