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Commit 090e73fb authored by Niels Dossche's avatar Niels Dossche Committed by Greg Kroah-Hartman
Browse files

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: 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>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 1d4bdaaa

net/ipv6/addrconf.c

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

	    nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid))

		goto error;

		goto error;





	spin_lock_bh(&ifa->lock);

	if (!((ifa->flags&IFA_F_PERMANENT) &&

	if (!((ifa->flags&IFA_F_PERMANENT) &&

	      (ifa->prefered_lft == INFINITY_LIFE_TIME))) {

	      (ifa->prefered_lft == INFINITY_LIFE_TIME))) {

		preferred = ifa->prefered_lft;

		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;

		preferred = INFINITY_LIFE_TIME;

		valid = INFINITY_LIFE_TIME;

		valid = INFINITY_LIFE_TIME;

	}

	}

	spin_unlock_bh(&ifa->lock);





	if (!ipv6_addr_any(&ifa->peer_addr)) {

	if (!ipv6_addr_any(&ifa->peer_addr)) {

		if (nla_put_in6_addr(skb, IFA_LOCAL, &ifa->addr) < 0 ||

		if (nla_put_in6_addr(skb, IFA_LOCAL, &ifa->addr) < 0 ||