From: Maciej Żenczykowski maze@google.com
[ 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@resnulli.us Fixes: 53bd67491537 ("ipv6 addrconf: introduce IFA_F_MANAGETEMPADDR to tell kernel to manage temporary addresses") Reported-by: Xiao Ma xiaom@google.com Signed-off-by: Maciej Żenczykowski maze@google.com Reviewed-by: David Ahern dsahern@kernel.org Link: https://lore.kernel.org/r/20230720160022.1887942-1-maze@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 46e3c939958bb..a4c3cb72bdc6a 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2541,12 +2541,18 @@ 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, false);