Re: [PATCH] time: Fix off-by-one in compat settimeofday() usec validation

[Arnd Bergmann]

On Mon, Jun 22, 2026, at 12:33, Wang Yan wrote:
> The compat version of settimeofday() uses '>' instead of '>=' when
> validating tv_usec against USEC_PER_SEC, allowing the value 1000000
> to pass the check. After the subsequent conversion to nanoseconds
> (tv_nsec *= NSEC_PER_USEC), this results in tv_nsec == NSEC_PER_SEC,
> which violates the timespec invariant that tv_nsec must be strictly
> less than NSEC_PER_SEC.
>
> The native settimeofday() was already fixed in commit ce4abda5e126
> ("time: Fix off-by-one in settimeofday() usec validation"), but the
> compat counterpart was missed.
>
> Fix it by using '>=' to reject tv_usec values outside the valid
> range [0, USEC_PER_SEC - 1].
>
> Fixes: 5e0fb1b57bea ("y2038: time: avoid timespec usage in settimeofday()")
> Signed-off-by: Wang Yan <wangyan01@xxxxxxxxxx>

Acked-by: Arnd Bergmann <arnd@xxxxxxxx>

probably also

Cc: stable@xxxxxxxxxxxxxxx