From 40008e921133f95685ca4dfd7233b3df96af2bd6 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 17 Jun 2019 16:02:27 +0200 Subject: [PATCH] net: ipv4: remove erroneous advancement of list pointer Causes crash when lifetime expires on an adress as garbage is dereferenced soon after. This used to look like this: for (ifap = &ifa->ifa_dev->ifa_list; *ifap != NULL; ifap = &(*ifap)->ifa_next) { if (*ifap == ifa) ... but this was changed to: struct in_ifaddr *tmp; ifap = &ifa->ifa_dev->ifa_list; tmp = rtnl_dereference(*ifap); while (tmp) { tmp = rtnl_dereference(tmp->ifa_next); // Bogus if (rtnl_dereference(*ifap) == ifa) { ... ifap = &tmp->ifa_next; // Can be NULL tmp = rtnl_dereference(*ifap); // Dereference } } Remove the bogus assigment/list entry skip. Fixes: 2638eb8b50cf ("net: ipv4: provide __rcu annotation for ifa_list") Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 925dffa915cb..914ccc7f192a 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -745,8 +745,7 @@ static void check_lifetime(struct work_struct *work) ifap = &ifa->ifa_dev->ifa_list; tmp = rtnl_dereference(*ifap); while (tmp) { - tmp = rtnl_dereference(tmp->ifa_next); - if (rtnl_dereference(*ifap) == ifa) { + if (tmp == ifa) { inet_del_ifa(ifa->ifa_dev, ifap, 1); break; -- 2.30.2