From: Dmitry Vyukov <dvyukov@google.com>
To: pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de,
davem@davemloft.net, kuznet@ms2.inr.ac.ru,
yoshfuji@linux-ipv6.org, edumazet@google.com, willemb@google.com
Cc: Dmitry Vyukov <dvyukov@google.com>,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller@googlegroups.com
Subject: [PATCH] netfilter: fix out-of-bounds accesses in clusterip_tg_check()
Date: Tue, 30 Jan 2018 15:21:34 +0100 [thread overview]
Message-ID: <20180130142134.131750-1-dvyukov@google.com> (raw)
Commit 136e92bbec0a switched local_nodes from an array to a bitmask
but did not add proper bounds checks. As the result
clusterip_config_init_nodelist() can both over-read
ipt_clusterip_tgt_info.local_nodes and over-write
clusterip_config.local_nodes.
Add bounds checks for both.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 136e92bbec0a ("[NETFILTER] CLUSTERIP: use a bitmap to store node responsibility data")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: netfilter-devel@vger.kernel.org
Cc: coreteam@netfilter.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 69060e3abe85..1e4a7209a3d2 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -431,7 +431,7 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
const struct ipt_entry *e = par->entryinfo;
struct clusterip_config *config;
- int ret;
+ int ret, i;
if (par->nft_compat) {
pr_err("cannot use CLUSTERIP target from nftables compat\n");
@@ -450,8 +450,18 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
pr_info("Please specify destination IP\n");
return -EINVAL;
}
-
- /* FIXME: further sanity checks */
+ if (cipinfo->num_local_nodes > ARRAY_SIZE(cipinfo->local_nodes)) {
+ pr_info("bad num_local_nodes %u\n", cipinfo->num_local_nodes);
+ return -EINVAL;
+ }
+ for (i = 0; i < cipinfo->num_local_nodes; i++) {
+ if (cipinfo->local_nodes[i] - 1 >=
+ sizeof(config->local_nodes) * 8) {
+ pr_info("bad local_nodes[%d] %u\n",
+ i, cipinfo->local_nodes[i]);
+ return -EINVAL;
+ }
+ }
config = clusterip_config_find_get(par->net, e->ip.dst.s_addr, 1);
if (!config) {
--
2.16.0.rc1.238.g530d649a79-goog
next reply other threads:[~2018-01-30 14:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-30 14:21 Dmitry Vyukov [this message]
2018-01-31 14:00 ` [PATCH] netfilter: fix out-of-bounds accesses in clusterip_tg_check() Pablo Neira Ayuso
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