From: Dmitry Vyukov Date: Tue, 30 Jan 2018 14:21:34 +0000 (+0100) Subject: netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=3f58460c0e71b46a812dad1831b92149ee785071;hp=da6941f4cc37699b2ff3894d279ca439548f768a netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() 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 Reported-by: syzbot Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings --- diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index a639967eb727..db6785cec2dd 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -354,7 +354,7 @@ 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 (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP && cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT && @@ -368,8 +368,18 @@ 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(e->ip.dst.s_addr, 1); if (!config) {