From: Niels Dossche Date: Wed, 23 Feb 2022 13:19:56 +0000 (+0100) Subject: ipv6: prevent a possible race condition with lifetimes X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=041616a22c40b7093c90010e2f52581776d4392a;p=linux.git 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 --- diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index e852bbc839dd8..1fe27807e471a 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 ||