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authorDaniel Hokka Zakrisson <daniel@hozac.com>2008-03-20 15:07:10 -0700
committerDavid S. Miller <davem@davemloft.net>2008-03-20 15:07:10 -0700
commitd0ebf133590abdc035af6e19a6568667af0ab3b0 (patch)
treea17acfb490969d7a99c902feab1d29ac6acbde2f
parent6aebb9b280e5662ece41cf570e25e61795443985 (diff)
[NETFILTER]: ipt_recent: sanity check hit count
If a rule using ipt_recent is created with a hit count greater than ip_pkt_list_tot, the rule will never match as it cannot keep track of enough timestamps. This patch makes ipt_recent refuse to create such rules. With ip_pkt_list_tot's default value of 20, the following can be used to reproduce the problem. nc -u -l 0.0.0.0 1234 & for i in `seq 1 100`; do echo $i | nc -w 1 -u 127.0.0.1 1234; done This limits it to 20 packets: iptables -A OUTPUT -p udp --dport 1234 -m recent --set --name test \ --rsource iptables -A OUTPUT -p udp --dport 1234 -m recent --update --seconds \ 60 --hitcount 20 --name test --rsource -j DROP While this is unlimited: iptables -A OUTPUT -p udp --dport 1234 -m recent --set --name test \ --rsource iptables -A OUTPUT -p udp --dport 1234 -m recent --update --seconds \ 60 --hitcount 21 --name test --rsource -j DROP With the patch the second rule-set will throw an EINVAL. Reported-by: Sean Kennedy <skennedy@vcn.com> Signed-off-by: Daniel Hokka Zakrisson <daniel@hozac.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/netfilter/ipt_recent.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_recent.c b/net/ipv4/netfilter/ipt_recent.c
index 68cbe3ca01c..8e8f0425a8e 100644
--- a/net/ipv4/netfilter/ipt_recent.c
+++ b/net/ipv4/netfilter/ipt_recent.c
@@ -252,6 +252,8 @@ recent_mt_check(const char *tablename, const void *ip,
if ((info->check_set & (IPT_RECENT_SET | IPT_RECENT_REMOVE)) &&
(info->seconds || info->hit_count))
return false;
+ if (info->hit_count > ip_pkt_list_tot)
+ return false;
if (info->name[0] == '\0' ||
strnlen(info->name, IPT_RECENT_NAME_LEN) == IPT_RECENT_NAME_LEN)
return false;