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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Steffen Klassert <steffen.klassert@secunet.com>
Subject: [PATCH 5.15 709/846] xfrm: fix dflt policy check when there is no policy configured
Date:   Mon, 24 Jan 2022 19:43:46 +0100
Message-Id: <20220124184125.491447877@linuxfoundation.org>
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From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

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@vger.kernel.org
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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);