From 05ee6e46a2f4b080b720b410d01a5d5bb9fa3a08 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Thu, 21 Nov 2019 00:03:03 +0000 Subject: [PATCH] time: Zero the upper 32-bits in __kernel_timespec on 32-bit 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 Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191121000303.126523-1-dima@arista.com Signed-off-by: Greg Kroah-Hartman --- kernel/time/time.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/time/time.c b/kernel/time/time.c index 5c54ca632d08..83f403e7a15c 100644 --- 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;