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| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-03 19:22:48 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-29 17:40:44 -0800 |
| commit | 5f4d5404ee8af904b8e843a7fc21f27ff8e6cb83 (patch) | |
| tree | f6eefb66ca2a87479fefad13276388c089fba0a3 | |
| parent | cfaa6851b052bc98519e8ba2d5a95bf30ff8ee48 (diff) | |
| download | lwn-5f4d5404ee8af904b8e843a7fc21f27ff8e6cb83.tar.gz lwn-5f4d5404ee8af904b8e843a7fc21f27ff8e6cb83.zip | |
time: settimeofday: Validate the values of tv from user
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>
| -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 8c42cf8d2444..5989b0ead1ec 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 a9ae20fb0b11..22d5d3b73970 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; } |