Patchwork [1/4] netfilter: ipset: fix timeout value overflow bug

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Submitter Pablo Neira
Date May 14, 2012, 11:47 a.m.
Message ID <1336996023-20249-2-git-send-email-pablo@netfilter.org>
Download mbox | patch
Permalink /patch/158971/
State Not Applicable
Headers show

Comments

Pablo Neira - May 14, 2012, 11:47 a.m.
From: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

Large timeout parameters could result wrong timeout values due to
an overflow at msec to jiffies conversion (reported by Andreas Herz)

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/netfilter/ipset/ip_set_timeout.h |    4 ++++
 net/netfilter/xt_set.c                         |   15 +++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)
David Laight - May 14, 2012, 2:19 p.m.
> --- a/include/linux/netfilter/ipset/ip_set_timeout.h
> +++ b/include/linux/netfilter/ipset/ip_set_timeout.h
> @@ -30,6 +30,10 @@ ip_set_timeout_uget(struct nlattr *tb)
>  {
>  	unsigned int timeout = ip_set_get_h32(tb);
>  
> +	/* Normalize to fit into jiffies */
> +	if (timeout > UINT_MAX/1000)
> +		timeout = UINT_MAX/1000;
> +

Doesn't that rather assume that HZ is 1000 ?

	David
 


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Patch

diff --git a/include/linux/netfilter/ipset/ip_set_timeout.h b/include/linux/netfilter/ipset/ip_set_timeout.h
index 4792320..9fba34f 100644
--- a/include/linux/netfilter/ipset/ip_set_timeout.h
+++ b/include/linux/netfilter/ipset/ip_set_timeout.h
@@ -30,6 +30,10 @@  ip_set_timeout_uget(struct nlattr *tb)
 {
 	unsigned int timeout = ip_set_get_h32(tb);
 
+	/* Normalize to fit into jiffies */
+	if (timeout > UINT_MAX/1000)
+		timeout = UINT_MAX/1000;
+
 	/* Userspace supplied TIMEOUT parameter: adjust crazy size */
 	return timeout == IPSET_NO_TIMEOUT ? IPSET_NO_TIMEOUT - 1 : timeout;
 }
diff --git a/net/netfilter/xt_set.c b/net/netfilter/xt_set.c
index 0ec8138..e97a31b 100644
--- a/net/netfilter/xt_set.c
+++ b/net/netfilter/xt_set.c
@@ -44,6 +44,14 @@  const struct ip_set_adt_opt n = {	\
 	.cmdflags = cfs,		\
 	.timeout = t,			\
 }
+#define ADT_MOPT(n, f, d, fs, cfs, t)	\
+struct ip_set_adt_opt n = {		\
+	.family	= f,			\
+	.dim = d,			\
+	.flags = fs,			\
+	.cmdflags = cfs,		\
+	.timeout = t,			\
+}
 
 /* Revision 0 interface: backward compatible with netfilter/iptables */
 
@@ -296,11 +304,14 @@  static unsigned int
 set_target_v2(struct sk_buff *skb, const struct xt_action_param *par)
 {
 	const struct xt_set_info_target_v2 *info = par->targinfo;
-	ADT_OPT(add_opt, par->family, info->add_set.dim,
-		info->add_set.flags, info->flags, info->timeout);
+	ADT_MOPT(add_opt, par->family, info->add_set.dim,
+		 info->add_set.flags, info->flags, info->timeout);
 	ADT_OPT(del_opt, par->family, info->del_set.dim,
 		info->del_set.flags, 0, UINT_MAX);
 
+	/* Normalize to fit into jiffies */
+	if (add_opt.timeout > UINT_MAX/1000)
+		add_opt.timeout = UINT_MAX/1000;
 	if (info->add_set.index != IPSET_INVALID_ID)
 		ip_set_add(info->add_set.index, skb, par, &add_opt);
 	if (info->del_set.index != IPSET_INVALID_ID)