From 1a38956cce5eabd7b74f94bab70265e4df83165e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Tue, 30 Jan 2018 15:21:34 +0100 Subject: netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() 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 Reported-by: syzbot Signed-off-by: Pablo Neira Ayuso --- 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) { -- cgit v1.2.3-59-g8ed1b