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Commit 45a07695 authored by Christoph Paasch's avatar Christoph Paasch Committed by David S. Miller
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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 76f10177 ([TCP]: TCP Veno congestion
control) was made by 15913114 (tcp: Overflow bug in Vegas), but it
failed to add the required cast in tcp_veno_cong_avoid().

Fixes: 76f10177 ([TCP]: TCP Veno congestion control)
Signed-off-by: default avatarChristoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 95cb5745

net/ipv4/tcp_veno.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -144,7 +144,7 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) 




		rtt = veno->minrtt;

		rtt = veno->minrtt;





		target_cwnd = (tp->snd_cwnd * veno->basertt);

		target_cwnd = (u64)tp->snd_cwnd * veno->basertt;

		target_cwnd <<= V_PARAM_SHIFT;

		target_cwnd <<= V_PARAM_SHIFT;

		do_div(target_cwnd, rtt);

		do_div(target_cwnd, rtt);