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Commit 1a38956c authored by Dmitry Vyukov's avatar Dmitry Vyukov Committed by Pablo Neira Ayuso
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netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() 



Commit 136e92bb 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: 136e92bb ("[NETFILTER] CLUSTERIP: use a bitmap to store node responsibility data")
Signed-off-by: default avatarDmitry Vyukov <dvyukov@google.com>
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 1e98ffea

net/ipv4/netfilter/ipt_CLUSTERIP.c

+13 −3
Original line number Diff line number Diff line
@@ -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) {