oss-security - RE: CVE Request - Samsung Exynos GPU driver OOB read

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Date: Fri, 20 Jan 2017 00:19:34 +0800
From: "idl3r" <idler1984@...il.com>
To: <oss-security@...ts.openwall.com>
Cc: "'Anarcheuz Fritz'" <anarcheuz@...il.com>,
	<cve-assign@...re.org>
Subject: RE: CVE Request - Samsung Exynos GPU driver OOB read

Unfortunately, there is no official git for tracking from Samsung, so I
can't give a pointer to the particular commit.

The bug itself resides in
<root>/drivers/gpu/arm/t7xx/r5p0/mali_kbase_core_linux.c of the src tree, in
function kbase_dispatch which is the main ioctl dispatcher of the driver:

static mali_error kbase_dispatch(struct kbase_context *kctx, void * const
args, u32 args_size)
{
...
    /* setup complete, perform normal operation */

    switch (id) {
...
	case KBASE_FUNC_TMU_SKIP:
		{
/* MALI_SEC_INTEGRATION */
#ifdef CONFIG_SENSORS_SEC_THERMISTOR
#ifdef CONFIG_USE_VSYNC_SKIP
			struct kbase_uk_tmu_skip *tskip = args;
			int thermistor = sec_therm_get_ap_temperature();
			u32 i, t_index = tskip->num_ratiometer;

			for (i = 0; i < tskip->num_ratiometer; i++)
<== missing of boundary check
				if (thermistor >= tskip->temperature[i])
					t_index = i;

tskip->temperature is a uint32 array of static size(10 elements) and
tskip->num_ratiometer a uint32 which is user controlled. Since the boundary
check is missing, OOB read may happen leading to possible memory corruption.

-----Original Message-----
From: Greg KH [mailto:greg@...ah.com] 
Sent: Thursday, January 19, 2017 10:37 PM
To: oss-security@...ts.openwall.com
Cc: Anarcheuz Fritz <anarcheuz@...il.com>; cve-assign@...re.org
Subject: Re: [oss-security] CVE Request - Samsung Exynos GPU driver OOB read

On Thu, Jan 19, 2017 at 02:38:31PM +0800, Idler wrote:
> Hello,
> 
> I'd like to request CVE for the following security issue:
> 
> Security bulletin: 
> http://security.samsungmobile.com/smrupdate.html#SMR-JAN-2017
> 
> SVE-2016-6362: out of bound read in gpu driver
> 
> Severity: Low
> Affected versions: M(6.0), N(7.0) devices with Exynos AP chipsets 
> Reported on: May 31, 2016 Disclosure status: Privately disclosed.
> Vulnerability in gpu driver does not properly check the boundary of 
> buffers leading to a possible memory corruption.
> The applied patch avoids an illegal access to memory by checking the
boundary.
> 
> Source code:
> Source code of the affected GPU drivers (as part of the Linux kernel
> source) can be downloaded from Samsung Opensource Resource center:
> http://opensource.samsung.com/
> 
> The particular model of phone we used to reproduce this issue is:
> http://opensource.samsung.com/reception/receptionSub.do?method=sub&sub
> =F&searchValue=SM-G9200

Any pointer to the commit(s) that happened to resolve this issue?

thanks,

greg k-h

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