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| author | Deepa Dinamani <deepa.kernel@gmail.com> | 2018-03-13 21:03:31 -0700 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2018-04-19 13:31:39 +0200 |
| commit | ea2ce8f3514e2074a1910d8d721842d7341d5c81 (patch) | |
| tree | 6cd2f49fc736fa05993aaec0f6827c31aba9a617 /kernel/time/time.c | |
| parent | acf8870a62afd4f1b3c0b695aaa619df355c0851 (diff) | |
| download | linux-ea2ce8f3514e2074a1910d8d721842d7341d5c81.tar.gz | |
time: Fix get_timespec64() for y2038 safe compat interfaces
get/put_timespec64() interfaces will eventually be used for conversions between the new y2038 safe struct __kernel_timespec and struct timespec64. The new y2038 safe syscalls have a common entry for native and compat interfaces. 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. Note that clearing of bits is dependent on CONFIG_64BIT_TIME for now. This is until COMPAT_USE_64BIT_TIME has been handled correctly. x86 will be the first architecture that will use the CONFIG_64BIT_TIME. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'kernel/time/time.c')
| -rw-r--r-- | kernel/time/time.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/kernel/time/time.c b/kernel/time/time.c index df61143a54f6..ccd751e95fcb 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -853,9 +853,9 @@ struct timespec64 timespec64_add_safe(const struct timespec64 lhs, } int get_timespec64(struct timespec64 *ts, - const struct timespec __user *uts) + const struct __kernel_timespec __user *uts) { - struct timespec kts; + struct __kernel_timespec kts; int ret; ret = copy_from_user(&kts, uts, sizeof(kts)); @@ -863,6 +863,11 @@ int get_timespec64(struct timespec64 *ts, return -EFAULT; ts->tv_sec = kts.tv_sec; + + /* Zero out the padding for 32 bit systems or in compat mode */ + if (IS_ENABLED(CONFIG_64BIT_TIME) && (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall())) + kts.tv_nsec &= 0xFFFFFFFFUL; + ts->tv_nsec = kts.tv_nsec; return 0; @@ -870,12 +875,13 @@ int get_timespec64(struct timespec64 *ts, EXPORT_SYMBOL_GPL(get_timespec64); int put_timespec64(const struct timespec64 *ts, - struct timespec __user *uts) + struct __kernel_timespec __user *uts) { - struct timespec kts = { + struct __kernel_timespec kts = { .tv_sec = ts->tv_sec, .tv_nsec = ts->tv_nsec }; + return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(put_timespec64); |