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authorChristoph Paasch <christoph.paasch@uclouvain.be>2014-07-29 12:07:27 +0200
committerDavid S. Miller <davem@davemloft.net>2014-07-30 17:31:06 -0700
commit45a07695bc64b3ab5d6d2215f9677e5b8c05a7d0 (patch)
treeb47746b0b34696ce1234e087c6891f109cc5006e /net/ipv4/tcp_veno.c
parent95cb5745983c222867cc9ac593aebb2ad67d72c0 (diff)
downloadlinux-45a07695bc64b3ab5d6d2215f9677e5b8c05a7d0.tar.gz
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 76f1017757aa0 ([TCP]: TCP Veno congestion
control) was made by 159131149c2 (tcp: Overflow bug in Vegas), but it
failed to add the required cast in tcp_veno_cong_avoid().

Fixes: 76f1017757aa0 ([TCP]: TCP Veno congestion control)
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_veno.c')
-rw-r--r--net/ipv4/tcp_veno.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index 27b9825753d1..8276977d2c85 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -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);