From eeabd3135db422699f745526fc1ad70d81709aac 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 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 --- net/ipv6/addrconf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 3f23da8c0b102..6c8ab3e6e6fe1 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -4998,6 +4998,7 @@ 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; @@ -5019,6 +5020,7 @@ 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 || -- 2.39.5