Commit 6c0d8833 authored by Niels Dossche's avatar Niels Dossche Committed by Jakub Kicinski
Browse files

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: default avatarNiels Dossche <dossche.niels@gmail.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarNiels Dossche <niels.dossche@ugent.be>
Link: https://lore.kernel.org/r/20220223131954.6570-1-niels.dossche@ugent.be


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 7ff57e98

net/ipv6/addrconf.c

+2 −0
Original line number Diff line number Diff line
@@ -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 ||