4.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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 edumazet@google.com Cc: Gerrit Renker gerrit@erg.abdn.ac.uk Cc: dccp@vger.kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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");