From 533e33009897c7dd1b0424c0d4b3331b222d5681 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 21:58:18 +0800 Subject: [PATCH] netfilter: cttimeout: unlink timeout objs in the unconfirmed ct lists KASAN reported this bug: BUG: KASAN: use-after-free in icmp_packet+0x25/0x50 [nf_conntrack_ipv4] at addr ffff880002db08c8 Read of size 4 by task lt-nf-queue/19041 Call Trace: [] dump_stack+0x63/0x88 [] kasan_report_error+0x528/0x560 [] kasan_report+0x58/0x60 [] ? icmp_packet+0x25/0x50 [nf_conntrack_ipv4] [] __asan_load4+0x61/0x80 [] icmp_packet+0x25/0x50 [nf_conntrack_ipv4] [] nf_conntrack_in+0x550/0x980 [nf_conntrack] [] ? __nf_conntrack_confirm+0xb10/0xb10 [nf_conntrack] [ ... ] The main reason is that we missed to unlink the timeout objects in the unconfirmed ct lists, so we will access the timeout objects that have already been freed. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_cttimeout.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 6844c7af0b8f..139e0867e56e 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -302,7 +302,16 @@ static void ctnl_untimeout(struct net *net, struct ctnl_timeout *timeout) const struct hlist_nulls_node *nn; unsigned int last_hsize; spinlock_t *lock; - int i; + int i, cpu; + + for_each_possible_cpu(cpu) { + struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); + + spin_lock_bh(&pcpu->lock); + hlist_nulls_for_each_entry(h, nn, &pcpu->unconfirmed, hnnode) + untimeout(h, timeout); + spin_unlock_bh(&pcpu->lock); + } local_bh_disable(); restart: -- 2.20.1