From fcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 22 Sep 2014 13:19:44 -0700 Subject: tcp: avoid possible arithmetic overflows icsk_rto is a 32bit field, and icsk_backoff can reach 15 by default, or more if some sysctl (eg tcp_retries2) are changed. Better use 64bit to perform icsk_rto << icsk_backoff operations As Joe Perches suggested, add a helper for this. Yuchung spotted the tcp_v4_err() case. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 02fb66d4a018..13f3da4762e3 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3208,9 +3208,10 @@ static void tcp_ack_probe(struct sock *sk) * This function is not for random using! */ } else { + unsigned long when = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); + inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, - min(icsk->icsk_rto << icsk->icsk_backoff, TCP_RTO_MAX), - TCP_RTO_MAX); + when, TCP_RTO_MAX); } } -- cgit