LinuxTV Patchwork [v3] media: rga: fix NULL pointer dereferences, use-after-free, memory leak

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Submitter Kangjie Lu
Date March 14, 2019, 5:03 a.m.
Message ID <20190314050344.29790-1-kjlu@umn.edu>
Download mbox | patch
Permalink /patch/55047/
State Changes Requested
Delegated to: Hans Verkuil
Headers show

Comments

Kangjie Lu - March 14, 2019, 5:03 a.m.
1. dma_alloc_attrs, __get_free_pages can fail and return NULL.
Further uses of their return values lead to NULL pointer
dereferences

2. In the error-handling path, video_unregister_device uses
"rga->vfd" which has been freed by video_device_release

3. The error handling for v4l2_m2m_init and video_register_device
has memory-leak issues

The patch fixes the above issues.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/media/platform/rockchip/rga/rga.c | 26 ++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)
Steven Price - March 14, 2019, 10:30 a.m.
On 14/03/2019 05:03, Kangjie Lu wrote:
> 1. dma_alloc_attrs, __get_free_pages can fail and return NULL.
> Further uses of their return values lead to NULL pointer
> dereferences
> 
> 2. In the error-handling path, video_unregister_device uses
> "rga->vfd" which has been freed by video_device_release
> 
> 3. The error handling for v4l2_m2m_init and video_register_device
> has memory-leak issues
> 
> The patch fixes the above issues.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>

Reviewed-by: Steven Price <steven.price@arm.com>

Yes, that looks like it solves the issues with the clean up - thanks for
reworking it!

> ---
>  drivers/media/platform/rockchip/rga/rga.c | 26 ++++++++++++++++++++---
>  1 file changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
> index 5c653287185f..468365ceb99d 100644
> --- a/drivers/media/platform/rockchip/rga/rga.c
> +++ b/drivers/media/platform/rockchip/rga/rga.c
> @@ -889,11 +889,24 @@ static int rga_probe(struct platform_device *pdev)
>  	rga->cmdbuf_virt = dma_alloc_attrs(rga->dev, RGA_CMDBUF_SIZE,
>  					   &rga->cmdbuf_phy, GFP_KERNEL,
>  					   DMA_ATTR_WRITE_COMBINE);
> +	if (!rga->cmdbuf_virt) {
> +		ret = -ENOMEM;
> +		goto unreg_video_dev;
> +	}
>  
>  	rga->src_mmu_pages =
>  		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
> +	if (!rga->src_mmu_pages) {
> +		ret = -ENOMEM;
> +		goto free_dma_attrs;
> +	}
> +
>  	rga->dst_mmu_pages =
>  		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
> +	if (!rga->dst_mmu_pages) {
> +		ret = -ENOMEM;
> +		goto free_dst_pages;
> +	}
>  
>  	def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3;
>  	def_frame.size = def_frame.stride * def_frame.height;
> @@ -901,7 +914,7 @@ static int rga_probe(struct platform_device *pdev)
>  	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
>  	if (ret) {
>  		v4l2_err(&rga->v4l2_dev, "Failed to register video device\n");
> -		goto rel_vdev;
> +		goto free_pages;
>  	}
>  
>  	v4l2_info(&rga->v4l2_dev, "Registered %s as /dev/%s\n",
> @@ -909,10 +922,17 @@ static int rga_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> -rel_vdev:
> -	video_device_release(vfd);
> +free_pages:
> +	free_pages((unsigned long)rga->src_mmu_pages, 3);
> +free_dst_pages:
> +	free_pages((unsigned long)rga->dst_mmu_pages, 3);

Minor comment: free_pages accepts a NULL pointer (or more precisely 0,
since it takes an unsigned long), it just returns having done nothing.
So there isn't actually any harm in calling free_pages unconditionally
in the error path (since rga is initialised to all zeros). You can save
a couple of labels in the error path using that trick.

Thanks,

Steve

> +free_dma_attrs:
> +	dma_free_attrs(rga->dev, RGA_CMDBUF_SIZE, rga->cmdbuf_virt,
> +		       rga->cmdbuf_phy,
> +		       DMA_ATTR_WRITE_COMBINE);
>  unreg_video_dev:
>  	video_unregister_device(rga->vfd);
> +	video_device_release(vfd);
>  unreg_v4l2_dev:
>  	v4l2_device_unregister(&rga->v4l2_dev);
>  err_put_clk:
>
Hans Verkuil - March 28, 2019, 2:47 p.m.
Hi Kangjie,

Unfortunately there are more issues with the cleanup sequence in
this probe function:

On 3/14/19 6:03 AM, Kangjie Lu wrote:
> 1. dma_alloc_attrs, __get_free_pages can fail and return NULL.
> Further uses of their return values lead to NULL pointer
> dereferences
> 
> 2. In the error-handling path, video_unregister_device uses
> "rga->vfd" which has been freed by video_device_release
> 
> 3. The error handling for v4l2_m2m_init and video_register_device
> has memory-leak issues
> 
> The patch fixes the above issues.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/media/platform/rockchip/rga/rga.c | 26 ++++++++++++++++++++---
>  1 file changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
> index 5c653287185f..468365ceb99d 100644
> --- a/drivers/media/platform/rockchip/rga/rga.c
> +++ b/drivers/media/platform/rockchip/rga/rga.c
> @@ -889,11 +889,24 @@ static int rga_probe(struct platform_device *pdev)
>  	rga->cmdbuf_virt = dma_alloc_attrs(rga->dev, RGA_CMDBUF_SIZE,
>  					   &rga->cmdbuf_phy, GFP_KERNEL,
>  					   DMA_ATTR_WRITE_COMBINE);
> +	if (!rga->cmdbuf_virt) {
> +		ret = -ENOMEM;
> +		goto unreg_video_dev;

Actually, the unreg_video_dev label makes no sense: if the video device
is successfully registered, then probe() returns 0. So you never need to
unregister the video device again. You *do* need to release it with
video_device_release().

So this should be a goto rel_vdev.

And the cleanup sequence at the end also fails to call v4l2_m2m_release().

Can you make v4?

Thanks!

	Hans

> +	}
>  
>  	rga->src_mmu_pages =
>  		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
> +	if (!rga->src_mmu_pages) {
> +		ret = -ENOMEM;
> +		goto free_dma_attrs;
> +	}
> +
>  	rga->dst_mmu_pages =
>  		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
> +	if (!rga->dst_mmu_pages) {
> +		ret = -ENOMEM;
> +		goto free_dst_pages;
> +	}
>  
>  	def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3;
>  	def_frame.size = def_frame.stride * def_frame.height;
> @@ -901,7 +914,7 @@ static int rga_probe(struct platform_device *pdev)
>  	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
>  	if (ret) {
>  		v4l2_err(&rga->v4l2_dev, "Failed to register video device\n");
> -		goto rel_vdev;
> +		goto free_pages;
>  	}
>  
>  	v4l2_info(&rga->v4l2_dev, "Registered %s as /dev/%s\n",
> @@ -909,10 +922,17 @@ static int rga_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> -rel_vdev:
> -	video_device_release(vfd);
> +free_pages:
> +	free_pages((unsigned long)rga->src_mmu_pages, 3);
> +free_dst_pages:
> +	free_pages((unsigned long)rga->dst_mmu_pages, 3);
> +free_dma_attrs:
> +	dma_free_attrs(rga->dev, RGA_CMDBUF_SIZE, rga->cmdbuf_virt,
> +		       rga->cmdbuf_phy,
> +		       DMA_ATTR_WRITE_COMBINE);
>  unreg_video_dev:
>  	video_unregister_device(rga->vfd);
> +	video_device_release(vfd);
>  unreg_v4l2_dev:
>  	v4l2_device_unregister(&rga->v4l2_dev);
>  err_put_clk:
>
Kangjie Lu - March 28, 2019, 3 p.m.
On 3/28/19 9:47 AM, Hans Verkuil wrote:
> Hi Kangjie,
>
> Unfortunately there are more issues with the cleanup sequence in
> this probe function:
>
> On 3/14/19 6:03 AM, Kangjie Lu wrote:
>> 1. dma_alloc_attrs, __get_free_pages can fail and return NULL.
>> Further uses of their return values lead to NULL pointer
>> dereferences
>>
>> 2. In the error-handling path, video_unregister_device uses
>> "rga->vfd" which has been freed by video_device_release
>>
>> 3. The error handling for v4l2_m2m_init and video_register_device
>> has memory-leak issues
>>
>> The patch fixes the above issues.
>>
>> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
>> ---
>>   drivers/media/platform/rockchip/rga/rga.c | 26 ++++++++++++++++++++---
>>   1 file changed, 23 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
>> index 5c653287185f..468365ceb99d 100644
>> --- a/drivers/media/platform/rockchip/rga/rga.c
>> +++ b/drivers/media/platform/rockchip/rga/rga.c
>> @@ -889,11 +889,24 @@ static int rga_probe(struct platform_device *pdev)
>>   	rga->cmdbuf_virt = dma_alloc_attrs(rga->dev, RGA_CMDBUF_SIZE,
>>   					   &rga->cmdbuf_phy, GFP_KERNEL,
>>   					   DMA_ATTR_WRITE_COMBINE);
>> +	if (!rga->cmdbuf_virt) {
>> +		ret = -ENOMEM;
>> +		goto unreg_video_dev;
> Actually, the unreg_video_dev label makes no sense: if the video device
> is successfully registered, then probe() returns 0. So you never need to
> unregister the video device again. You *do* need to release it with
> video_device_release().
>
> So this should be a goto rel_vdev.
>
> And the cleanup sequence at the end also fails to call v4l2_m2m_release().
>
> Can you make v4?


Thanks for the feedback. Will send a v4.


>
> Thanks!
>
> 	Hans
>
>> +	}
>>   
>>   	rga->src_mmu_pages =
>>   		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
>> +	if (!rga->src_mmu_pages) {
>> +		ret = -ENOMEM;
>> +		goto free_dma_attrs;
>> +	}
>> +
>>   	rga->dst_mmu_pages =
>>   		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
>> +	if (!rga->dst_mmu_pages) {
>> +		ret = -ENOMEM;
>> +		goto free_dst_pages;
>> +	}
>>   
>>   	def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3;
>>   	def_frame.size = def_frame.stride * def_frame.height;
>> @@ -901,7 +914,7 @@ static int rga_probe(struct platform_device *pdev)
>>   	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
>>   	if (ret) {
>>   		v4l2_err(&rga->v4l2_dev, "Failed to register video device\n");
>> -		goto rel_vdev;
>> +		goto free_pages;
>>   	}
>>   
>>   	v4l2_info(&rga->v4l2_dev, "Registered %s as /dev/%s\n",
>> @@ -909,10 +922,17 @@ static int rga_probe(struct platform_device *pdev)
>>   
>>   	return 0;
>>   
>> -rel_vdev:
>> -	video_device_release(vfd);
>> +free_pages:
>> +	free_pages((unsigned long)rga->src_mmu_pages, 3);
>> +free_dst_pages:
>> +	free_pages((unsigned long)rga->dst_mmu_pages, 3);
>> +free_dma_attrs:
>> +	dma_free_attrs(rga->dev, RGA_CMDBUF_SIZE, rga->cmdbuf_virt,
>> +		       rga->cmdbuf_phy,
>> +		       DMA_ATTR_WRITE_COMBINE);
>>   unreg_video_dev:
>>   	video_unregister_device(rga->vfd);
>> +	video_device_release(vfd);
>>   unreg_v4l2_dev:
>>   	v4l2_device_unregister(&rga->v4l2_dev);
>>   err_put_clk:
>>

Patch

diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
index 5c653287185f..468365ceb99d 100644
--- a/drivers/media/platform/rockchip/rga/rga.c
+++ b/drivers/media/platform/rockchip/rga/rga.c
@@ -889,11 +889,24 @@  static int rga_probe(struct platform_device *pdev)
 	rga->cmdbuf_virt = dma_alloc_attrs(rga->dev, RGA_CMDBUF_SIZE,
 					   &rga->cmdbuf_phy, GFP_KERNEL,
 					   DMA_ATTR_WRITE_COMBINE);
+	if (!rga->cmdbuf_virt) {
+		ret = -ENOMEM;
+		goto unreg_video_dev;
+	}
 
 	rga->src_mmu_pages =
 		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
+	if (!rga->src_mmu_pages) {
+		ret = -ENOMEM;
+		goto free_dma_attrs;
+	}
+
 	rga->dst_mmu_pages =
 		(unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3);
+	if (!rga->dst_mmu_pages) {
+		ret = -ENOMEM;
+		goto free_dst_pages;
+	}
 
 	def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3;
 	def_frame.size = def_frame.stride * def_frame.height;
@@ -901,7 +914,7 @@  static int rga_probe(struct platform_device *pdev)
 	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
 	if (ret) {
 		v4l2_err(&rga->v4l2_dev, "Failed to register video device\n");
-		goto rel_vdev;
+		goto free_pages;
 	}
 
 	v4l2_info(&rga->v4l2_dev, "Registered %s as /dev/%s\n",
@@ -909,10 +922,17 @@  static int rga_probe(struct platform_device *pdev)
 
 	return 0;
 
-rel_vdev:
-	video_device_release(vfd);
+free_pages:
+	free_pages((unsigned long)rga->src_mmu_pages, 3);
+free_dst_pages:
+	free_pages((unsigned long)rga->dst_mmu_pages, 3);
+free_dma_attrs:
+	dma_free_attrs(rga->dev, RGA_CMDBUF_SIZE, rga->cmdbuf_virt,
+		       rga->cmdbuf_phy,
+		       DMA_ATTR_WRITE_COMBINE);
 unreg_video_dev:
 	video_unregister_device(rga->vfd);
+	video_device_release(vfd);
 unreg_v4l2_dev:
 	v4l2_device_unregister(&rga->v4l2_dev);
 err_put_clk:

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