5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 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@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 2be7d26434180..af67e19eba392 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 88d53d37fbe96..3cc22f776a313 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); }