Patch "xfrm: notify default policy on update" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    xfrm: notify default policy on update

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfrm-notify-default-policy-on-update.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bacd28f3be200acc3d7d055b36936b5ff44bd9a1
Author: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Date:   Tue Sep 14 16:46:34 2021 +0200

    xfrm: notify default policy on update
    
    [ Upstream commit 88d0adb5f13b1c52fbb7d755f6f79db18c2f0c2c ]
    
    This configuration knob is very sensible, it should be notified when
    changing.
    
    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: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 261953e081fb..4152f6399205 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1914,6 +1914,36 @@ static struct sk_buff *xfrm_policy_netlink(struct sk_buff *in_skb,
 	return skb;
 }
 
+static int xfrm_notify_userpolicy(struct net *net)
+{
+	struct xfrm_userpolicy_default *up;
+	int len = NLMSG_ALIGN(sizeof(*up));
+	struct nlmsghdr *nlh;
+	struct sk_buff *skb;
+
+	skb = nlmsg_new(len, GFP_ATOMIC);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	nlh = nlmsg_put(skb, 0, 0, XFRM_MSG_GETDEFAULT, sizeof(*up), 0);
+	if (nlh == NULL) {
+		kfree_skb(skb);
+		return -EMSGSIZE;
+	}
+
+	up = nlmsg_data(nlh);
+	up->in = net->xfrm.policy_default & XFRM_POL_DEFAULT_IN ?
+			XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
+	up->fwd = net->xfrm.policy_default & XFRM_POL_DEFAULT_FWD ?
+			XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
+	up->out = net->xfrm.policy_default & XFRM_POL_DEFAULT_OUT ?
+			XFRM_USERPOLICY_BLOCK : XFRM_USERPOLICY_ACCEPT;
+
+	nlmsg_end(skb, nlh);
+
+	return xfrm_nlmsg_multicast(net, skb, 0, XFRMNLGRP_POLICY);
+}
+
 static int xfrm_set_default(struct sk_buff *skb, struct nlmsghdr *nlh,
 			    struct nlattr **attrs)
 {
@@ -1937,6 +1967,7 @@ static int xfrm_set_default(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	rt_genid_bump_all(net);
 
+	xfrm_notify_userpolicy(net);
 	return 0;
 }