From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Gerrit Renker , dccp@vger.kernel.org, "David S. Miller" Subject: [PATCH 4.4 14/31] net: dccp: switch rx_tstamp_last_feedback to monotonic clock Date: Fri, 20 Jul 2018 14:13:44 +0200 Message-Id: <20180720121340.671722543@linuxfoundation.org> In-Reply-To: <20180720121340.158484922@linuxfoundation.org> References: <20180720121340.158484922@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 0ce4e70ff00662ad7490e545ba0cd8c1fa179fca ] To compute delays, better not use time of the day which can be changed by admins or malicious programs. Also change ccid3_first_li() to use s64 type for delta variable to avoid potential overflows. Signed-off-by: Eric Dumazet Cc: Gerrit Renker Cc: dccp@vger.kernel.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dccp/ccids/ccid3.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -599,7 +599,7 @@ static void ccid3_hc_rx_send_feedback(st { struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); struct dccp_sock *dp = dccp_sk(sk); - ktime_t now = ktime_get_real(); + ktime_t now = ktime_get(); s64 delta = 0; switch (fbtype) { @@ -631,7 +631,7 @@ static void ccid3_hc_rx_send_feedback(st return; } - ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta, + ccid3_pr_debug("Interval %lldusec, X_recv=%u, 1/p=%u\n", delta, hc->rx_x_recv, hc->rx_pinv); hc->rx_tstamp_last_feedback = now; @@ -678,7 +678,8 @@ static int ccid3_hc_rx_insert_options(st static u32 ccid3_first_li(struct sock *sk) { struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); - u32 x_recv, p, delta; + u32 x_recv, p; + s64 delta; u64 fval; if (hc->rx_rtt == 0) { @@ -686,7 +687,9 @@ static u32 ccid3_first_li(struct sock *s hc->rx_rtt = DCCP_FALLBACK_RTT; } - delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback)); + delta = ktime_us_delta(ktime_get(), hc->rx_tstamp_last_feedback); + if (delta <= 0) + delta = 1; x_recv = scaled_div32(hc->rx_bytes_recv, delta); if (x_recv == 0) { /* would also trigger divide-by-zero */ DCCP_WARN("X_recv==0\n");