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tcp: Fix integer-overflows in TCP veno 

In veno we do a multiplication of the cwnd and the rtt. This
may overflow and thus their result is stored in a u64. However, we first
need to cast the cwnd so that actually 64-bit arithmetic is done.

A first attempt at fixing 76f1017757 ([TCP]: TCP Veno congestion
control) was made by 159131149c (tcp: Overflow bug in Vegas), but it
failed to add the required cast in tcp_veno_cong_avoid().

Fixes: 76f1017757 ([TCP]: TCP Veno congestion control)
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christoph Paasch 2014-07-29 12:07:27 +02:00 committed by David S. Miller
parent 95cb574598
commit 45a07695bc
1 changed files with 1 additions and 1 deletions
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2
net/ipv4/tcp_veno.c
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@ -144,7 +144,7 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked)
rtt = veno->minrtt;
target_cwnd = (tp->snd_cwnd * veno->basertt);
target_cwnd = (u64)tp->snd_cwnd * veno->basertt;
target_cwnd <<= V_PARAM_SHIFT;
do_div(target_cwnd, rtt);