[PATCH 5.16 0881/1039] xfrm: fix dflt policy check when there is no policy configured

From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 17:48:21 EST


From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>

commit ec3bb890817e4398f2d46e12e2e205495b116be9 upstream.

When there is no policy configured on the system, the default policy is
checked in xfrm_route_forward. However, it was done with the wrong
direction (XFRM_POLICY_FWD instead of XFRM_POLICY_OUT).
The default policy for XFRM_POLICY_FWD was checked just before, with a call
to xfrm[46]_policy_check().

CC: stable@xxxxxxxxxxxxxxx
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/xfrm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1167,7 +1167,7 @@ static inline int xfrm_route_forward(str
{
struct net *net = dev_net(skb->dev);

- if (xfrm_default_allow(net, XFRM_POLICY_FWD))
+ if (xfrm_default_allow(net, XFRM_POLICY_OUT))
return !net->xfrm.policy_count[XFRM_POLICY_OUT] ||
(skb_dst(skb)->flags & DST_NOXFRM) ||
__xfrm_route_forward(skb, family);