From: Maciej Żenczykowski <maze@xxxxxxxxxx>
[ Upstream commit 69172f0bcb6a09110c5d2a6d792627f5095a9018 ]
currently on 6.4 net/main:
# ip link add dummy1 type dummy
# echo 1 > /proc/sys/net/ipv6/conf/dummy1/use_tempaddr
# ip link set dummy1 up
# ip -6 addr add 2000::1/64 mngtmpaddr dev dummy1
# ip -6 addr show dev dummy1
11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::44f3:581c:8ca:3983/64 scope global temporary dynamic
valid_lft 604800sec preferred_lft 86172sec
inet6 2000::1/64 scope global mngtmpaddr
valid_lft forever preferred_lft forever
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever
# ip -6 addr del 2000::44f3:581c:8ca:3983/64 dev dummy1
(can wait a few seconds if you want to, the above delete isn't [directly] the problem)
# ip -6 addr show dev dummy1
11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::1/64 scope global mngtmpaddr
valid_lft forever preferred_lft forever
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever
# ip -6 addr del 2000::1/64 mngtmpaddr dev dummy1
# ip -6 addr show dev dummy1
11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
inet6 2000::81c9:56b7:f51a:b98f/64 scope global temporary dynamic
valid_lft 604797sec preferred_lft 86169sec
inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
valid_lft forever preferred_lft forever
This patch prevents this new 'global temporary dynamic' address from being
created by the deletion of the related (same subnet prefix) 'mngtmpaddr'
(which is triggered by there already being no temporary addresses).
Cc: Jiri Pirko <jiri@xxxxxxxxxxx>
Fixes: 53bd67491537 ("ipv6 addrconf: introduce IFA_F_MANAGETEMPADDR to tell kernel to manage temporary addresses")
Reported-by: Xiao Ma <xiaom@xxxxxxxxxx>
Signed-off-by: Maciej Żenczykowski <maze@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230720160022.1887942-1-maze@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv6/addrconf.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6703a5b65e4a6..893b93cc5221a 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2436,12 +2436,18 @@ static void manage_tempaddrs(struct inet6_dev *idev,
ipv6_ifa_notify(0, ift);
}
- if ((create || list_empty(&idev->tempaddr_list)) &&
- idev->cnf.use_tempaddr > 0) {
+ /* Also create a temporary address if it's enabled but no temporary
+ * address currently exists.
+ * However, we get called with valid_lft == 0, prefered_lft == 0, create == false
+ * as part of cleanup (ie. deleting the mngtmpaddr).
+ * We don't want that to result in creating a new temporary ip address.
+ */
+ if (list_empty(&idev->tempaddr_list) && (valid_lft || prefered_lft))
+ create = true;
+
+ if (create && idev->cnf.use_tempaddr > 0) {
/* When a new public address is created as described
* in [ADDRCONF], also create a new temporary address.
- * Also create a temporary address if it's enabled but
- * no temporary address currently exists.
*/
read_unlock_bh(&idev->lock);
ipv6_create_tempaddr(ifp, NULL);
--
2.39.2
