linux-kernel - [ 142/147] netfilter: xt_limit: have r->cost != 0 case work

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Message-Id: <20121014143552.971003867@decadent.org.uk>
Date:	Sun, 14 Oct 2012 15:37:55 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Jan Engelhardt <jengelh@...i.de>,
	Pablo Neira Ayuso <pablo@...filter.org>
Subject: [ 142/147] netfilter: xt_limit: have r->cost != 0 case work

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

------------------

From: Jan Engelhardt <jengelh@...i.de>

commit 82e6bfe2fbc4d48852114c4f979137cd5bf1d1a8 upstream.

Commit v2.6.19-rc1~1272^2~41 tells us that r->cost != 0 can happen when
a running state is saved to userspace and then reinstated from there.

Make sure that private xt_limit area is initialized with correct values.
Otherwise, random matchings due to use of uninitialized memory.

Signed-off-by: Jan Engelhardt <jengelh@...i.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 net/netfilter/xt_limit.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/xt_limit.c b/net/netfilter/xt_limit.c
index 5c22ce8..a4c1e45 100644
--- a/net/netfilter/xt_limit.c
+++ b/net/netfilter/xt_limit.c
@@ -117,11 +117,11 @@ static int limit_mt_check(const struct xt_mtchk_param *par)
 
 	/* For SMP, we only want to use one set of state. */
 	r->master = priv;
+	/* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies *
+	   128. */
+	priv->prev = jiffies;
+	priv->credit = user2credits(r->avg * r->burst); /* Credits full. */
 	if (r->cost == 0) {
-		/* User avg in seconds * XT_LIMIT_SCALE: convert to jiffies *
-		   128. */
-		priv->prev = jiffies;
-		priv->credit = user2credits(r->avg * r->burst); /* Credits full. */
 		r->credit_cap = priv->credit; /* Credits full. */
 		r->cost = user2credits(r->avg);
 	}


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