5.15-stable review patch. If anyone has any objections, please let me know.

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From: Miroslav Lichvar mlichvar@redhat.com

[ Upstream commit 5a8c02a6bf52b1cf9cfb7868a8330f7c3c6aebe9 ]

Networking drivers implementing PTP clocks and kernel socket code handling hardware timestamps use the 64-bit signed ktime_t type counting nanoseconds. When a PTP clock reaches the maximum value in year 2262, the timestamps returned to applications will overflow into year 1667. The same thing happens when injecting a large offset with clock_adjtime(ADJ_SETOFFSET).

The commit 7a8e61f84786 ("timekeeping: Force upper bound for setting CLOCK_REALTIME") limited the maximum accepted value setting the system clock to 30 years before the maximum representable value (i.e. year 2232) to avoid the overflow, assuming the system will not run for more than 30 years.

Enforce the same limit for PTP clocks. Don't allow negative values and values closer than 30 years to the maximum value. Drivers may implement an even lower limit if the hardware registers cannot represent the whole interval between years 1970 and 2262 in the required resolution.

Signed-off-by: Miroslav Lichvar mlichvar@redhat.com Cc: Richard Cochran richardcochran@gmail.com Cc: Thomas Gleixner tglx@linutronix.de Cc: John Stultz jstultz@google.com Cc: Arnd Bergmann arnd@arndb.de Reviewed-by: Vadim Fedorenko vadim.fedorenko@linux.dev Link: https://patch.msgid.link/20250828103300.1387025-1-mlichvar@redhat.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/ptp/ptp_clock.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c index 2e4e425288b26..d6dee90bed35f 100644 --- a/drivers/ptp/ptp_clock.c +++ b/drivers/ptp/ptp_clock.c @@ -83,6 +83,9 @@ static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp return -EBUSY; }

+ if (!timespec64_valid_settod(tp)) + return -EINVAL; + return ptp->info->settime64(ptp->info, tp); }

@@ -112,7 +115,7 @@ static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx) ops = ptp->info;

if (tx->modes & ADJ_SETOFFSET) { - struct timespec64 ts; + struct timespec64 ts, ts2; ktime_t kt; s64 delta;

@@ -125,6 +128,14 @@ static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx) if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) return -EINVAL;

+ /* Make sure the offset is valid */ + err = ptp_clock_gettime(pc, &ts2); + if (err) + return err; + ts2 = timespec64_add(ts2, ts); + if (!timespec64_valid_settod(&ts2)) + return -EINVAL; + kt = timespec64_to_ktime(ts); delta = ktime_to_ns(kt); err = ops->adjtime(ops, delta);