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authorCong Wang <xiyou.wangcong@gmail.com>2020-03-14 08:29:54 +0300
committerDavid S. Miller <davem@davemloft.net>2020-03-16 11:59:32 +0300
commitef299cc3fa1a9e1288665a9fdc8bff55629fd359 (patch)
tree260bd9b4c8d37f9770b4b04e30663812728079d8 /net/sched
parent4ae649e8879d5a96b0ce104c8eae6563c6f368a1 (diff)
downloadlinux-ef299cc3fa1a9e1288665a9fdc8bff55629fd359.tar.xz
net_sched: cls_route: remove the right filter from hashtable
route4_change() allocates a new filter and copies values from the old one. After the new filter is inserted into the hash table, the old filter should be removed and freed, as the final step of the update. However, the current code mistakenly removes the new one. This looks apparently wrong to me, and it causes double "free" and use-after-free too, as reported by syzbot. Reported-and-tested-by: syzbot+f9b32aaacd60305d9687@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+2f8c233f131943d6056d@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+9c2df9fd5e9445b74e01@syzkaller.appspotmail.com Fixes: 1109c00547fc ("net: sched: RCU cls_route") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/cls_route.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index 6f8786b06bde..5efa3e7ace15 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -534,8 +534,8 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
fp = &b->ht[h];
for (pfp = rtnl_dereference(*fp); pfp;
fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
- if (pfp == f) {
- *fp = f->next;
+ if (pfp == fold) {
+ rcu_assign_pointer(*fp, fold->next);
break;
}
}