diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2017-07-18 14:56:17 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-07-19 11:53:25 +0200 |
| commit | 3840538ad384fb7891adeeaf36624f870c51fc0e (patch) | |
| tree | dbc5a3421471d450deb7bd525294a94da466a993 /net/ipv4 | |
| parent | 073dd5ad34b1d3aaadaa7e5e8cbe576d9545f163 (diff) | |
netfilter: ipt_CLUSTERIP: fix use-after-free of proc entry
When we delete a netns with a CLUSTERIP rule, clusterip_net_exit() is
called first, removing /proc/net/ipt_CLUSTERIP.
Then clusterip_config_entry_put() is called from clusterip_tg_destroy(),
and tries to remove its entry under /proc/net/ipt_CLUSTERIP/.
Fix this by checking that the parent directory of the entry to remove
hasn't already been deleted.
The following triggers a KASAN splat (stealing the reproducer from
202f59afd441, thanks to Jianlin Shi and Xin Long):
ip netns add test
ip link add veth0_in type veth peer name veth0_out
ip link set veth0_in netns test
ip netns exec test ip link set lo up
ip netns exec test ip link set veth0_in up
ip netns exec test iptables -I INPUT -d 1.2.3.4 -i veth0_in -j \
CLUSTERIP --new --clustermac 89:d4:47:eb:9a:fa --total-nodes 3 \
--local-node 1 --hashmode sourceip-sourceport
ip netns del test
Fixes: ce4ff76c15a8 ("netfilter: ipt_CLUSTERIP: make proc directory per net namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/netfilter/ipt_CLUSTERIP.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 7d72decb80f9..efaa04dcc80e 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -117,7 +117,8 @@ clusterip_config_entry_put(struct net *net, struct clusterip_config *c) * functions are also incrementing the refcount on their own, * so it's safe to remove the entry even if it's in use. */ #ifdef CONFIG_PROC_FS - proc_remove(c->pde); + if (cn->procdir) + proc_remove(c->pde); #endif return; } @@ -815,6 +816,7 @@ static void clusterip_net_exit(struct net *net) #ifdef CONFIG_PROC_FS struct clusterip_net *cn = net_generic(net, clusterip_net_id); proc_remove(cn->procdir); + cn->procdir = NULL; #endif nf_unregister_net_hook(net, &cip_arp_ops); } |