[103/145] netfilter: xt_recent: fix buffer overflow

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let me know.

----------------
From: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>

commit 2c08522e5d2f0af2d6f05be558946dcbf8173683 upstream.

e->index overflows e->stamps[] every ip_pkt_list_tot packets.

Consider the case when ip_pkt_list_tot==1; the first packet received is stored
in e->stamps[0] and e->index is initialized to 1. The next received packet
timestamp is then stored at e->stamps[1] in recent_entry_update(),
a buffer overflow because the maximum e->stamps[] index is 0.

Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/netfilter/xt_recent.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -173,10 +173,10 @@ recent_entry_init(struct recent_table *t
 
 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
 {
+	e->index %= ip_pkt_list_tot;
 	e->stamps[e->index++] = jiffies;
 	if (e->index > e->nstamps)
 		e->nstamps = e->index;
-	e->index %= ip_pkt_list_tot;
 	list_move_tail(&e->lru_list, &t->lru_list);
 }
 


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