From edafe502404f3669d364b6e96d79b54067b634b4 Mon Sep 17 00:00:00 2001
From: Daniele Lacamera <root@danielinux.net>
Date: Wed, 2 Jun 2010 02:02:04 +0000
Subject: [PATCH] TCP: tcp_hybla: Fix integer overflow in slow start increment
For large values of rtt, 2^rho operation may overflow u32. Clamp down the increment to 2^16.
Signed-off-by: Daniele Lacamera <root@danielinux.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp_hybla.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c
index c209e054a634..377bc9349371 100644
--- a/net/ipv4/tcp_hybla.c
+++ b/net/ipv4/tcp_hybla.c
@@ -126,8 +126,8 @@ static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
* calculate 2^fract in a <<7 value.
*/
is_slowstart = 1;
- increment = ((1 << ca->rho) * hybla_fraction(rho_fractions))
- - 128;
+ increment = ((1 << min(ca->rho, 16U)) *
+ hybla_fraction(rho_fractions)) - 128;
} else {
/*
* congestion avoidance
--
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