This is a note to let you know that I've just added the patch titled
ipv6: prevent a possible race condition with lifetimes
to the 5.4-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:
ipv6-prevent-a-possible-race-condition-with-lifetime.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b4b9c1f7cddf9fa6f15ec7510fd2f373155c91c1
Author: Niels Dossche <dossche.niels@xxxxxxxxx>
Date: Wed Feb 23 14:19:56 2022 +0100
ipv6: prevent a possible race condition with lifetimes
[ Upstream commit 6c0d8833a605e195ae219b5042577ce52bf71fff ]
valid_lft, prefered_lft and tstamp are always accessed under the lock
"lock" in other places. Reading these without taking the lock may result
in inconsistencies regarding the calculation of the valid and preferred
variables since decisions are taken on these fields for those variables.
Signed-off-by: Niels Dossche <dossche.niels@xxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Signed-off-by: Niels Dossche <niels.dossche@xxxxxxxx>
Link: https://lore.kernel.org/r/20220223131954.6570-1-niels.dossche@xxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index d1f29a3eb70b..60d070b25484 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4924,6 +4924,7 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid))
goto error;
+ spin_lock_bh(&ifa->lock);
if (!((ifa->flags&IFA_F_PERMANENT) &&
(ifa->prefered_lft == INFINITY_LIFE_TIME))) {
preferred = ifa->prefered_lft;
@@ -4945,6 +4946,7 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
preferred = INFINITY_LIFE_TIME;
valid = INFINITY_LIFE_TIME;
}
+ spin_unlock_bh(&ifa->lock);
if (!ipv6_addr_any(&ifa->peer_addr)) {
if (nla_put_in6_addr(skb, IFA_LOCAL, &ifa->addr) < 0 ||
