From 041616a22c40b7093c90010e2f52581776d4392a Mon Sep 17 00:00:00 2001 From: Niels Dossche Date: Wed, 23 Feb 2022 14:19:56 +0100 Subject: [PATCH] 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 Reviewed-by: David Ahern Signed-off-by: Niels Dossche Link: https://lore.kernel.org/r/20220223131954.6570-1-niels.dossche@ugent.be Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/addrconf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index e852bbc..1fe2780 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5000,6 +5000,7 @@ 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; @@ -5021,6 +5022,7 @@ 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 || -- 2.7.4