[PATCH 4.9 024/145] netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check()
From: Greg Kroah-Hartman
Date: Fri Feb 23 2018 - 15:02:33 EST
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
commit 1a38956cce5eabd7b74f94bab70265e4df83165e upstream.
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.
Fixes: 136e92bbec0a ("[NETFILTER] CLUSTERIP: use a bitmap to store node responsibility data")
Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -365,7 +365,7 @@ static int clusterip_tg_check(const stru
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");
@@ -384,8 +384,18 @@ static int clusterip_tg_check(const stru
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) {