From: Cong Wang <xiyou.wangcong@gmail.com>
To: netdev@vger.kernel.org
Cc: fw@strlen.de, netfilter-devel@vger.kernel.org,
Cong Wang <xiyou.wangcong@gmail.com>,
syzbot+adf6c6c2be1c3a718121@syzkaller.appspotmail.com,
Pablo Neira Ayuso <pablo@netfilter.org>,
Jozsef Kadlecsik <kadlec@netfilter.org>
Subject: [Patch nf v2 3/3] xt_hashlimit: limit the max size of hashtable
Date: Sun, 2 Feb 2020 20:30:53 -0800 [thread overview]
Message-ID: <20200203043053.19192-4-xiyou.wangcong@gmail.com> (raw)
In-Reply-To: <20200203043053.19192-1-xiyou.wangcong@gmail.com>
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
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
net/netfilter/xt_hashlimit.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 06e59f9d9f62..60c023630d14 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -837,6 +837,8 @@ 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,
@@ -847,6 +849,14 @@ 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;
--
2.21.1
next prev parent reply other threads:[~2020-02-03 4:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 4:30 [Patch nf v2 0/3] netfilter: xt_hashlimit: a few improvements Cong Wang
2020-02-03 4:30 ` [Patch nf v2 1/3] xt_hashlimit: avoid OOM for user-controlled vmalloc Cong Wang
2020-02-03 12:16 ` Florian Westphal
2020-02-03 18:54 ` Cong Wang
2020-02-03 20:18 ` Florian Westphal
2020-02-07 14:57 ` Pablo Neira Ayuso
2020-02-03 4:30 ` [Patch nf v2 2/3] xt_hashlimit: reduce hashlimit_mutex scope for htable_put() Cong Wang
2020-02-07 14:54 ` Pablo Neira Ayuso
2020-02-03 4:30 ` Cong Wang [this message]
2020-02-03 12:06 ` [Patch nf v2 3/3] xt_hashlimit: limit the max size of hashtable Florian Westphal
2020-02-07 14:56 ` Pablo Neira Ayuso
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