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>
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index 27b9825..8276977 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -144,7 +144,7 @@
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);