From: Dmitry Safonov dima@arista.com
commit 7b8474466ed97be458c825f34a85f2c2b84c3f95 upstream.
On compat interfaces, the high order bits of nanoseconds should be zeroed out. This is because the application code or the libc do not guarantee zeroing of these. If used without zeroing, kernel might be at risk of using timespec values incorrectly.
Originally it was handled correctly, but lost during is_compat_syscall() cleanup. Revert the condition back to check CONFIG_64BIT.
Fixes: 98f76206b335 ("compat: Cleanup in_compat_syscall() callers") Reported-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Dmitry Safonov dima@arista.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191121000303.126523-1-dima@arista.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/time/time.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -881,7 +881,8 @@ int get_timespec64(struct timespec64 *ts ts->tv_sec = kts.tv_sec;
/* Zero out the padding for 32 bit systems or in compat mode */ - if (IS_ENABLED(CONFIG_64BIT_TIME) && in_compat_syscall()) + if (IS_ENABLED(CONFIG_64BIT_TIME) && (!IS_ENABLED(CONFIG_64BIT) || + in_compat_syscall())) kts.tv_nsec &= 0xFFFFFFFFUL;
ts->tv_nsec = kts.tv_nsec;