diff options
| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-03 19:22:48 -0500 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2015-01-07 09:49:14 -0800 |
| commit | 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 (patch) | |
| tree | b6a02726aa5f93ccb61e7161c7705590424f7830 | |
| parent | b2776bf7149bddd1f4161f14f79520f17fc1d71d (diff) | |
time: settimeofday: Validate the values of tv from user
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>
Cc: stable <stable@vger.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>
| -rw-r--r-- | include/linux/time.h | 13 | ||||
| -rw-r--r-- | kernel/time/time.c | 4 |
2 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h index 8c42cf8d244..5989b0ead1e 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -99,6 +99,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts) return true; } +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); #define CURRENT_TIME (current_kernel_time()) diff --git a/kernel/time/time.c b/kernel/time/time.c index a9ae20fb0b1..22d5d3b7397 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -196,6 +196,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, 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; } |