blob: 85c5e96b9e41b0033dce65ab4f9774fa888bc65e [file] [log] [blame]
From 15e098ef1fea07f6570a233f9d30732c66f16123 Mon Sep 17 00:00:00 2001
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Sun, 2 Feb 2020 20:30:53 -0800
Subject: [PATCH] netfilter: xt_hashlimit: limit the max size of hashtable
commit 8d0015a7ab76b8b1e89a3e5f5710a6e5103f2dd5 upstream.
The user-specified hashtable size is unbound, this could
easily lead to an OOM or a hung task as we hold the global
mutex while allocating and initializing the new hashtable.
Add a max value to cap both cfg->size and cfg->max, as
suggested by Florian.
Reported-and-tested-by: syzbot+adf6c6c2be1c3a718121@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 2d2691dd51e0..94e37d024b1f 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -846,6 +846,8 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
}
+#define HASHLIMIT_MAX_SIZE 1048576
+
static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
struct xt_hashlimit_htable **hinfo,
struct hashlimit_cfg3 *cfg,
@@ -856,6 +858,14 @@ static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
if (cfg->gc_interval == 0 || cfg->expire == 0)
return -EINVAL;
+ if (cfg->size > HASHLIMIT_MAX_SIZE) {
+ cfg->size = HASHLIMIT_MAX_SIZE;
+ pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
+ }
+ if (cfg->max > HASHLIMIT_MAX_SIZE) {
+ cfg->max = HASHLIMIT_MAX_SIZE;
+ pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
+ }
if (par->family == NFPROTO_IPV4) {
if (cfg->srcmask > 32 || cfg->dstmask > 32)
return -EINVAL;
--
2.7.4