| From 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sasha.levin@oracle.com> |
| Date: Wed, 3 Dec 2014 19:22:48 -0500 |
| Subject: time: settimeofday: Validate the values of tv from user |
| |
| From: Sasha Levin <sasha.levin@oracle.com> |
| |
| commit 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 upstream. |
| |
| An unvalidated user input is multiplied by a constant, which can result in |
| an undefined behaviour for large values. While this is validated later, |
| we should avoid triggering undefined behaviour. |
| |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Sasha Levin <sasha.levin@oracle.com> |
| [jstultz: include trivial milisecond->microsecond correction noticed |
| by Andy] |
| Signed-off-by: John Stultz <john.stultz@linaro.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| include/linux/time.h | 13 +++++++++++++ |
| kernel/time.c | 4 ++++ |
| 2 files changed, 17 insertions(+) |
| |
| --- a/include/linux/time.h |
| +++ b/include/linux/time.h |
| @@ -173,6 +173,19 @@ extern void getboottime(struct timespec |
| extern void monotonic_to_bootbased(struct timespec *ts); |
| extern void get_monotonic_boottime(struct timespec *ts); |
| |
| +static inline bool timeval_valid(const struct timeval *tv) |
| +{ |
| + /* Dates before 1970 are bogus */ |
| + if (tv->tv_sec < 0) |
| + return false; |
| + |
| + /* Can't have more microseconds then a second */ |
| + if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC) |
| + return false; |
| + |
| + return true; |
| +} |
| + |
| extern struct timespec timespec_trunc(struct timespec t, unsigned gran); |
| extern int timekeeping_valid_for_hres(void); |
| extern u64 timekeeping_max_deferment(void); |
| --- a/kernel/time.c |
| +++ b/kernel/time.c |
| @@ -195,6 +195,10 @@ SYSCALL_DEFINE2(settimeofday, struct tim |
| if (tv) { |
| if (copy_from_user(&user_tv, tv, sizeof(*tv))) |
| return -EFAULT; |
| + |
| + if (!timeval_valid(&user_tv)) |
| + return -EINVAL; |
| + |
| new_ts.tv_sec = user_tv.tv_sec; |
| new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; |
| } |