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authorEric Dumazet <edumazet@google.com>2018-06-22 06:44:15 -0700
committerDavid S. Miller <davem@davemloft.net>2018-06-23 10:46:44 +0900
commit0ce4e70ff00662ad7490e545ba0cd8c1fa179fca (patch)
tree4959b26fee49e3465efd6d73539b74d459340870 /net/dccp
parentnet: dccp: avoid crash in ccid3_hc_rx_send_feedback() (diff)
downloadlinux-dev-0ce4e70ff00662ad7490e545ba0cd8c1fa179fca.tar.xz
linux-dev-0ce4e70ff00662ad7490e545ba0cd8c1fa179fca.zip
net: dccp: switch rx_tstamp_last_feedback to monotonic clock
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>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ccids/ccid3.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index d57a2be1e2e0..12877a1514e7 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -600,7 +600,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
{
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) {
@@ -632,7 +632,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
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;
@@ -679,7 +679,8 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
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) {
@@ -687,7 +688,9 @@ static u32 ccid3_first_li(struct sock *sk)
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");