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From: Thomas Gleixner <tglx@linutronix.de>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: linux-kernel@vger.kernel.org, John Stultz <john.stultz@linaro.org>
Subject: Re: [PATCH] time: settimeofday: validate the values of tv fomr user
Date: Tue, 2 Dec 2014 12:16:43 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.11.1412021209020.3961@nanos> (raw)
In-Reply-To: <1417493050-13594-5-git-send-email-sasha.levin@oracle.com>

On Mon, 1 Dec 2014, Sasha Levin wrote:

> 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.
> 
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> ---
>  kernel/time/time.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/time/time.c b/kernel/time/time.c
> index 9ec4fa5..6f53df7 100644
> --- a/kernel/time/time.c
> +++ b/kernel/time/time.c
> @@ -200,6 +200,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
>  	if (tv) {
>  		if (copy_from_user(&user_tv, tv, sizeof(*tv)))
>  			return -EFAULT;
> +
> +		if (user_tv.tv_usec > USEC_PER_SEC || user_tv.tv_usec < 0)
> +			return -EINVAL;

We should create timeval_valid() for this with the same logic as
timespec_valid().

Thanks,

	tglx


  reply	other threads:[~2014-12-02 11:16 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-02  4:04 [PATCH] time: do a safe overflow check in ktime_add_safe Sasha Levin
2014-12-02  4:04 ` [PATCH] time: make sure tz_minuteswest is set to a valid value when setting time Sasha Levin
2014-12-02  4:04 ` [PATCH] vfs: calculate seek offsets using unsigned variables Sasha Levin
2014-12-02  4:04 ` [PATCH] mm: fadvise: avoid signed integer overflow calculating offset Sasha Levin
2014-12-02  4:04 ` [PATCH] time: settimeofday: validate the values of tv fomr user Sasha Levin
2014-12-02 11:16   ` Thomas Gleixner [this message]
2014-12-02  4:04 ` [PATCH] fs: sync_file_range: avoid overflowing signed calculation Sasha Levin

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