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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, Antony Antony <antony.antony@secunet.com>,
        Eyal Birger <eyal.birger@gmail.com>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 173/563] xfrm: interface with if_id 0 should return error
Date:   Mon, 24 Jan 2022 19:38:58 +0100
Message-Id: <20220124184030.397155595@linuxfoundation.org>
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From: Antony Antony <antony.antony@secunet.com>

[ Upstream commit 8dce43919566f06e865f7e8949f5c10d8c2493f5 ]

xfrm interface if_id = 0 would cause xfrm policy lookup errors since
Commit 9f8550e4bd9d.

Now explicitly fail to create an xfrm interface when if_id = 0

With this commit:
 ip link add ipsec0  type xfrm dev lo  if_id 0
 Error: if_id must be non zero.

v1->v2 change:
 - add Fixes: tag

Fixes: 9f8550e4bd9d ("xfrm: fix disable_xfrm sysctl when used on xfrm interfaces")
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/xfrm/xfrm_interface.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index e9ce23343f5ca..e1fae61a5bb90 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -643,11 +643,16 @@ static int xfrmi_newlink(struct net *src_net, struct net_device *dev,
 			struct netlink_ext_ack *extack)
 {
 	struct net *net = dev_net(dev);
-	struct xfrm_if_parms p;
+	struct xfrm_if_parms p = {};
 	struct xfrm_if *xi;
 	int err;
 
 	xfrmi_netlink_parms(data, &p);
+	if (!p.if_id) {
+		NL_SET_ERR_MSG(extack, "if_id must be non zero");
+		return -EINVAL;
+	}
+
 	xi = xfrmi_locate(net, &p);
 	if (xi)
 		return -EEXIST;
@@ -672,7 +677,12 @@ static int xfrmi_changelink(struct net_device *dev, struct nlattr *tb[],
 {
 	struct xfrm_if *xi = netdev_priv(dev);
 	struct net *net = xi->net;
-	struct xfrm_if_parms p;
+	struct xfrm_if_parms p = {};
+
+	if (!p.if_id) {
+		NL_SET_ERR_MSG(extack, "if_id must be non zero");
+		return -EINVAL;
+	}
 
 	xfrmi_netlink_parms(data, &p);
 	xi = xfrmi_locate(net, &p);
-- 
2.34.1