This is a note to let you know that I've just added the patch titled netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netfilter-ipt_clusterip-fix-out-of-bounds-accesses-in-clusterip_tg_check.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1a38956cce5eabd7b74f94bab70265e4df83165e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Date: Tue, 30 Jan 2018 15:21:34 +0100 Subject: netfilter: ipt_CLUSTERIP: fix out-of-bounds accesses in clusterip_tg_check() 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 (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP && cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT && @@ -379,8 +379,18 @@ 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) { Patches currently in stable-queue which might be from dvyukov@xxxxxxxxxx are queue-3.18/netfilter-x_tables-fix-int-overflow-in-xt_alloc_table_info.patch queue-3.18/netfilter-ipt_clusterip-fix-out-of-bounds-accesses-in-clusterip_tg_check.patch