5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 73ed8e03388d16c12fc577e5c700b58a29045a15 ]
cookie_init_timestamp() is supposed to return a 64bit timestamp
suitable for both TSval determination and setting of skb->tstamp.
Unfortunately it uses 32bit fields and overflows after
2^32 * 10^6 nsec (~49 days) of uptime.
Generated TSval are still correct, but skb->tstamp might be set
far away in the past, potentially confusing other layers.
tcp_ns_to_ts() is changed to return a full 64bit value,
ts and ts_now variables are changed to u64 type,
and TSMASK is removed in favor of shifts operations.
While we are at it, change this sequence:
ts >>= TSBITS;
ts--;
ts <<= TSBITS;
ts |= options;
to:
ts -= (1UL << TSBITS);
Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/tcp.h | 2 +-
net/ipv4/syncookies.c | 20 +++++++-------------
2 files changed, 8 insertions(+), 14 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 772e593910287..5c03dc6d0f792 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -776,7 +776,7 @@ static inline u32 tcp_time_stamp(const struct tcp_sock *tp)
}
/* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */
-static inline u32 tcp_ns_to_ts(u64 ns)
+static inline u64 tcp_ns_to_ts(u64 ns)
{
return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ);
}
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 542b66783493b..cc860f2dcf658 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -43,7 +43,6 @@ static siphash_key_t syncookie_secret[2] __read_mostly;
* requested/supported by the syn/synack exchange.
*/
#define TSBITS 6
-#define TSMASK (((__u32)1 << TSBITS) - 1)
static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
u32 count, int c)
@@ -64,27 +63,22 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
*/
u64 cookie_init_timestamp(struct request_sock *req, u64 now)
{
- struct inet_request_sock *ireq;
- u32 ts, ts_now = tcp_ns_to_ts(now);
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ u64 ts, ts_now = tcp_ns_to_ts(now);
u32 options = 0;
- ireq = inet_rsk(req);
-
options = ireq->wscale_ok ? ireq->snd_wscale : TS_OPT_WSCALE_MASK;
if (ireq->sack_ok)
options |= TS_OPT_SACK;
if (ireq->ecn_ok)
options |= TS_OPT_ECN;
- ts = ts_now & ~TSMASK;
+ ts = (ts_now >> TSBITS) << TSBITS;
ts |= options;
- if (ts > ts_now) {
- ts >>= TSBITS;
- ts--;
- ts <<= TSBITS;
- ts |= options;
- }
- return (u64)ts * (NSEC_PER_SEC / TCP_TS_HZ);
+ if (ts > ts_now)
+ ts -= (1UL << TSBITS);
+
+ return ts * (NSEC_PER_SEC / TCP_TS_HZ);
}
--
2.42.0
