From 40008e921133f95685ca4dfd7233b3df96af2bd6 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
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 <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 925dffa915cb8..914ccc7f192ae 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