netdev - [patch net-next 14/21] ipv6: Regenerate host route according to node pointer upon interface up

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu,  3 Aug 2017 13:28:24 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, idosch@...lanox.com, mlxsw@...lanox.com,
        dsahern@...il.com, roopa@...ulusnetworks.com,
        nikolay@...ulusnetworks.com, kafai@...com,
        hannes@...essinduktion.org, yoshfuji@...ux-ipv6.org,
        edumazet@...gle.com, yanhaishuang@...s.chinamobile.com
Subject: [patch net-next 14/21] ipv6: Regenerate host route according to node pointer upon interface up

From: Ido Schimmel <idosch@...lanox.com>

When an interface is brought back up, the kernel tries to restore the
host routes tied to its permanent addresses.

However, if the host route was removed from the FIB, then we need to
reinsert it. This is done by releasing the current dst and allocating a
new, so as to not reuse a dst with obsolete values.

Since this function is called under RTNL and using the same explanation
from the previous patch, we can test if the route is in the FIB by
checking its node pointer instead of its reference count.

Tested using the following script and Andrey's reproducer mentioned
in commit 8048ced9beb2 ("net: ipv6: regenerate host route if moved to gc
list") and linked below:

$ ip link set dev lo up
$ ip link add dummy1 type dummy
$ ip -6 address add cafe::1/64 dev dummy1
$ ip link set dev lo down	# cafe::1/128 is removed
$ ip link set dev dummy1 up
$ ip link set dev lo up

The host route is correctly regenerated.

Signed-off-by: Ido Schimmel <idosch@...lanox.com>
Link: http://lkml.kernel.org/r/CAAeHK+zSe82vc5gCRgr_EoUwiALPnWVdWJBPwJZBpbxYz=kGJw@mail.gmail.com
Signed-off-by: Jiri Pirko <jiri@...lanox.com>
---
 net/ipv6/addrconf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e8e4f86..30ee23e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3321,11 +3321,11 @@ static void addrconf_gre_config(struct net_device *dev)
 static int fixup_permanent_addr(struct inet6_dev *idev,
 				struct inet6_ifaddr *ifp)
 {
-	/* rt6i_ref == 0 means the host route was removed from the
+	/* !rt6i_node means the host route was removed from the
 	 * FIB, for example, if 'lo' device is taken down. In that
 	 * case regenerate the host route.
 	 */
-	if (!ifp->rt || !atomic_read(&ifp->rt->rt6i_ref)) {
+	if (!ifp->rt || !ifp->rt->rt6i_node) {
 		struct rt6_info *rt, *prev;
 
 		rt = addrconf_dst_alloc(idev, &ifp->addr, false);
-- 
2.9.3