[PATCH 0/2] time: tip/timers/urgent: Validate potential mult overflows

[PATCH 0/2] time: tip/timers/urgent: Validate potential mult overflows

[John Stultz]

Hey Ingo, Thomas,

 Here are two mult overflow validation fixes from Sasha for
tip/timers/urgent that I didn't manage to send out before the holidays.

Let me know if you have any objections.

thanks
-john

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Sasha Levin <sasha.levin@oracle.com>

If you want they can be pulled via:

The following changes since commit b2776bf7149bddd1f4161f14f79520f17fc1d71d:

  Linux 3.18 (2014-12-07 14:21:05 -0800)

are available in the git repository at:

  https://git.linaro.org/people/john.stultz/linux.git fortglx/3.19-stable/time

for you to fetch changes up to ac1e640cd8d3f5baf48103fdbf794788034bf50c:

  time: adjtimex: Validate the ADJ_FREQUENCY values (2014-12-19 12:07:10 -0800)

----------------------------------------------------------------
Sasha Levin (2):
      time: settimeofday: Validate the values of tv from user
      time: adjtimex: Validate the ADJ_FREQUENCY values

 include/linux/time.h | 13 +++++++++++++
 kernel/time/ntp.c    |  7 +++++++
 kernel/time/time.c   |  4 ++++
 3 files changed, 24 insertions(+)

-- 
1.9.1

[PATCH 1/2] time: settimeofday: Validate the values of tv from user

[John Stultz]

From: Sasha Levin <sasha.levin@oracle.com>

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>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 include/linux/time.h | 13 +++++++++++++
 kernel/time/time.c   |  4 ++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/time.h b/include/linux/time.h
index 8c42cf8..7a10ec1 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 miliseconds 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 a9ae20f..22d5d3b 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;
 	}
-- 
1.9.1

[PATCH 2/2] time: adjtimex: Validate the ADJ_FREQUENCY values

[John Stultz]

From: Sasha Levin <sasha.levin@oracle.com>

Verify that the frequency value from userspace is valid and makes sense.

Unverified values can cause overflows later on.

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: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/ntp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 87a346f..28bf91c 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -633,6 +633,13 @@ int ntp_validate_timex(struct timex *txc)
 	if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
 		return -EPERM;
 
+	if (txc->modes & ADJ_FREQUENCY) {
+		if (LONG_MIN / PPM_SCALE > txc->freq)
+			return -EINVAL;
+		if (LONG_MAX / PPM_SCALE < txc->freq)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
1.9.1

Re: [PATCH 1/2] time: settimeofday: Validate the values of tv from user

[Andy Lutomirski]

On 01/02/2015 11:51 AM, John Stultz wrote:
> From: Sasha Levin <sasha.levin@oracle.com>
> 
> 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>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
>  include/linux/time.h | 13 +++++++++++++
>  kernel/time/time.c   |  4 ++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/include/linux/time.h b/include/linux/time.h
> index 8c42cf8..7a10ec1 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 miliseconds then a second */

Trivial nit: that should be "microseconds".

--Andy

> +	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 a9ae20f..22d5d3b 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;
>  	}
> 

[PATCH 2/2] time: adjtimex: Validate the ADJ_FREQUENCY values

[John Stultz]

From: Sasha Levin <sasha.levin@oracle.com>

Verify that the frequency value from userspace is valid and makes sense.

Unverified values can cause overflows later on.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/ntp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 87a346f..28bf91c 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -633,6 +633,13 @@ int ntp_validate_timex(struct timex *txc)
 	if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
 		return -EPERM;
 
+	if (txc->modes & ADJ_FREQUENCY) {
+		if (LONG_MIN / PPM_SCALE > txc->freq)
+			return -EINVAL;
+		if (LONG_MAX / PPM_SCALE < txc->freq)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
1.9.1

Re: [PATCH 2/2] time: adjtimex: Validate the ADJ_FREQUENCY values

[Greg KH]

On Wed, Jan 07, 2015 at 10:12:20AM -0800, John Stultz wrote:
> From: Sasha Levin <sasha.levin@oracle.com>
> 
> Verify that the frequency value from userspace is valid and makes sense.
> 
> Unverified values can cause overflows later on.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: stable <stable@vger.kernel.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> [jstultz: Fix up bug for negative values and drop redunent cap check]
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
>  kernel/time/ntp.c | 7 +++++++
>  1 file changed, 7 insertions(+)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>