[PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[Marek Szyprowski]

Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
structure fits into provided GEM buffers. Without this check it is
possible to create a framebuffer object from a small buffer and set it to
the hardware, what results in displaying system memory outside the
allocated GEM buffer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: stable@vger.kernel.org # v4.7+
---
This issue was there from the beggining, but the provided patch applies only
to v4.7+ kernels due to other changes in the fixed code.
---
 drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index d48fd7c918f8..73217c281c9a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -145,13 +145,19 @@ struct drm_framebuffer *
 exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		      const struct drm_mode_fb_cmd2 *mode_cmd)
 {
+	const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
 	struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
 	struct drm_gem_object *obj;
 	struct drm_framebuffer *fb;
 	int i;
 	int ret;
 
-	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
+	for (i = 0; i < info->num_planes; i++) {
+		unsigned int height = (i == 0) ? mode_cmd->height :
+				     DIV_ROUND_UP(mode_cmd->height, info->vsub);
+		unsigned long size = height * mode_cmd->pitches[i] +
+				     mode_cmd->offsets[i];
+
 		obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
 		if (!obj) {
 			DRM_ERROR("failed to lookup gem object\n");
@@ -160,6 +166,12 @@ struct drm_framebuffer *
 		}
 
 		exynos_gem[i] = to_exynos_gem(obj);
+
+		if (size > exynos_gem[i]->size) {
+			i++;
+			ret = -EINVAL;
+			goto err;
+		}
 	}
 
 	fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);
-- 
1.9.1

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[PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[Marek Szyprowski]

Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
structure fits into provided GEM buffers. Without this check it is
possible to create a framebuffer object from a small buffer and set it to
the hardware, what results in displaying system memory outside the
allocated GEM buffer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: stable@vger.kernel.org # v4.7+
---
This issue was there from the beggining, but the provided patch applies only
to v4.7+ kernels due to other changes in the fixed code.
---
 drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index d48fd7c918f8..73217c281c9a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -145,13 +145,19 @@ struct drm_framebuffer *
 exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		      const struct drm_mode_fb_cmd2 *mode_cmd)
 {
+	const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
 	struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
 	struct drm_gem_object *obj;
 	struct drm_framebuffer *fb;
 	int i;
 	int ret;
 
-	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
+	for (i = 0; i < info->num_planes; i++) {
+		unsigned int height = (i == 0) ? mode_cmd->height :
+				     DIV_ROUND_UP(mode_cmd->height, info->vsub);
+		unsigned long size = height * mode_cmd->pitches[i] +
+				     mode_cmd->offsets[i];
+
 		obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
 		if (!obj) {
 			DRM_ERROR("failed to lookup gem object\n");
@@ -160,6 +166,12 @@ struct drm_framebuffer *
 		}
 
 		exynos_gem[i] = to_exynos_gem(obj);
+
+		if (size > exynos_gem[i]->size) {
+			i++;
+			ret = -EINVAL;
+			goto err;
+		}
 	}
 
 	fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);
-- 
1.9.1

Re: [PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[Marek Szyprowski]

Hi all,

On 2017-07-12 12:09, Marek Szyprowski wrote:
> Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
> structure fits into provided GEM buffers. Without this check it is
> possible to create a framebuffer object from a small buffer and set it to
> the hardware, what results in displaying system memory outside the
> allocated GEM buffer.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> CC: stable@vger.kernel.org # v4.7+

Gentle ping.

> ---
> This issue was there from the beggining, but the provided patch applies only
> to v4.7+ kernels due to other changes in the fixed code.
> ---
>   drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
> index d48fd7c918f8..73217c281c9a 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
> @@ -145,13 +145,19 @@ struct drm_framebuffer *
>   exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
>   		      const struct drm_mode_fb_cmd2 *mode_cmd)
>   {
> +	const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
>   	struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
>   	struct drm_gem_object *obj;
>   	struct drm_framebuffer *fb;
>   	int i;
>   	int ret;
>   
> -	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
> +	for (i = 0; i < info->num_planes; i++) {
> +		unsigned int height = (i == 0) ? mode_cmd->height :
> +				     DIV_ROUND_UP(mode_cmd->height, info->vsub);
> +		unsigned long size = height * mode_cmd->pitches[i] +
> +				     mode_cmd->offsets[i];
> +
>   		obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
>   		if (!obj) {
>   			DRM_ERROR("failed to lookup gem object\n");
> @@ -160,6 +166,12 @@ struct drm_framebuffer *
>   		}
>   
>   		exynos_gem[i] = to_exynos_gem(obj);
> +
> +		if (size > exynos_gem[i]->size) {
> +			i++;
> +			ret = -EINVAL;
> +			goto err;
> +		}
>   	}
>   
>   	fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[Tobias Jakobi]

Hello Marek,

I have a similar patch in my tree, so this one is

Reviewed-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>

- Tobias


Marek Szyprowski wrote:
> Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
> structure fits into provided GEM buffers. Without this check it is
> possible to create a framebuffer object from a small buffer and set it to
> the hardware, what results in displaying system memory outside the
> allocated GEM buffer.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> CC: stable@vger.kernel.org # v4.7+
> ---
> This issue was there from the beggining, but the provided patch applies only
> to v4.7+ kernels due to other changes in the fixed code.
> ---
>  drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
> index d48fd7c918f8..73217c281c9a 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
> @@ -145,13 +145,19 @@ struct drm_framebuffer *
>  exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
>  		      const struct drm_mode_fb_cmd2 *mode_cmd)
>  {
> +	const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
>  	struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
>  	struct drm_gem_object *obj;
>  	struct drm_framebuffer *fb;
>  	int i;
>  	int ret;
>  
> -	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
> +	for (i = 0; i < info->num_planes; i++) {
> +		unsigned int height = (i == 0) ? mode_cmd->height :
> +				     DIV_ROUND_UP(mode_cmd->height, info->vsub);
> +		unsigned long size = height * mode_cmd->pitches[i] +
> +				     mode_cmd->offsets[i];
> +
>  		obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
>  		if (!obj) {
>  			DRM_ERROR("failed to lookup gem object\n");
> @@ -160,6 +166,12 @@ struct drm_framebuffer *
>  		}
>  
>  		exynos_gem[i] = to_exynos_gem(obj);
> +
> +		if (size > exynos_gem[i]->size) {
> +			i++;
> +			ret = -EINVAL;
> +			goto err;
> +		}
>  	}
>  
>  	fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);
> 

Re: [PATCH] drm/exynos: forbid creating framebuffers from too small GEM buffers

[Inki Dae]

2017년 08월 08일 22:33에 Marek Szyprowski 이(가) 쓴 글:
> Hi all,
> 
> On 2017-07-12 12:09, Marek Szyprowski wrote:
>> Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
>> structure fits into provided GEM buffers. Without this check it is
>> possible to create a framebuffer object from a small buffer and set it to
>> the hardware, what results in displaying system memory outside the
>> allocated GEM buffer.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> CC: stable@vger.kernel.org # v4.7+
> 
> Gentle ping.

Applied.

Thanks,
Inki Dae

> 
>> ---
>> This issue was there from the beggining, but the provided patch applies only
>> to v4.7+ kernels due to other changes in the fixed code.
>> ---
>>   drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
>>   1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
>> index d48fd7c918f8..73217c281c9a 100644
>> --- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
>> +++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
>> @@ -145,13 +145,19 @@ struct drm_framebuffer *
>>   exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
>>                 const struct drm_mode_fb_cmd2 *mode_cmd)
>>   {
>> +    const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
>>       struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
>>       struct drm_gem_object *obj;
>>       struct drm_framebuffer *fb;
>>       int i;
>>       int ret;
>>   -    for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
>> +    for (i = 0; i < info->num_planes; i++) {
>> +        unsigned int height = (i == 0) ? mode_cmd->height :
>> +                     DIV_ROUND_UP(mode_cmd->height, info->vsub);
>> +        unsigned long size = height * mode_cmd->pitches[i] +
>> +                     mode_cmd->offsets[i];
>> +
>>           obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
>>           if (!obj) {
>>               DRM_ERROR("failed to lookup gem object\n");
>> @@ -160,6 +166,12 @@ struct drm_framebuffer *
>>           }
>>             exynos_gem[i] = to_exynos_gem(obj);
>> +
>> +        if (size > exynos_gem[i]->size) {
>> +            i++;
>> +            ret = -EINVAL;
>> +            goto err;
>> +        }
>>       }
>>         fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);
> 
> Best regards
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