[4.2.y-ckt stable] Patch "ipv6, token: allow for clearing the current device token" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ipv6, token: allow for clearing the current device token

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 929a45cf5adbb5c754999b17219b0673b080e27a Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <daniel at iogearbox.net>
Date: Fri, 8 Apr 2016 15:55:00 +0200
Subject: ipv6, token: allow for clearing the current device token

commit 47e27d5e92c46a3a62d4dfd8895b1ddb8613f531 upstream.

The original tokenized iid support implemented via f53adae4eae5 ("net: ipv6:
add tokenized interface identifier support") didn't allow for clearing a
device token as it was intended that this addressing mode was the only one
active for globally scoped IPv6 addresses. Later we relaxed that restriction
via 617fe29d45bd ("net: ipv6: only invalidate previously tokenized addresses"),
and we should also allow for clearing tokens as there's no good reason why
it shouldn't be allowed.

Fixes: 617fe29d45bd ("net: ipv6: only invalidate previously tokenized addresses")
Reported-by: Robin H. Johnson <robbat2 at gentoo.org>
Signed-off-by: Daniel Borkmann <daniel at iogearbox.net>
Cc: Hannes Frederic Sowa <hannes at stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv6/addrconf.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 335f495..135f1b8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4737,15 +4737,13 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)
 {
 	struct inet6_ifaddr *ifp;
 	struct net_device *dev = idev->dev;
-	bool update_rs = false;
+	bool clear_token, update_rs = false;
 	struct in6_addr ll_addr;

 	ASSERT_RTNL();

 	if (!token)
 		return -EINVAL;
-	if (ipv6_addr_any(token))
-		return -EINVAL;
 	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP))
 		return -EINVAL;
 	if (!ipv6_accept_ra(idev))
@@ -4760,10 +4758,13 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)

 	write_unlock_bh(&idev->lock);

+	clear_token = ipv6_addr_any(token);
+	if (clear_token)
+		goto update_lft;
+
 	if (!idev->dead && (idev->if_flags & IF_READY) &&
 	    !ipv6_get_lladdr(dev, &ll_addr, IFA_F_TENTATIVE |
 			     IFA_F_OPTIMISTIC)) {
-
 		/* If we're not ready, then normal ifup will take care
 		 * of this. Otherwise, we need to request our rs here.
 		 */
@@ -4771,6 +4772,7 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token)
 		update_rs = true;
 	}

+update_lft:
 	write_lock_bh(&idev->lock);

 	if (update_rs) {
--
2.7.4