[v1] Venus driver fixes to avoid possible OOB accesses

[PATCH 4/4] media: venus: hfi: add a check to handle OOB in sfr region

Posted by Vikash Garodia 2 weeks, 5 days ago

sfr->buf_size is in shared memory and can be modified by malicious user.
OOB write is possible when the size is made higher than actual sfr data
buffer.

Cc: stable@vger.kernel.org
Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
---
 drivers/media/platform/qcom/venus/hfi_venus.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
index 50d92214190d88eff273a5ba3f95486f758bcc05..c19d6bf686d0f31c6a2f551de3f7eb08031bde85 100644
--- a/drivers/media/platform/qcom/venus/hfi_venus.c
+++ b/drivers/media/platform/qcom/venus/hfi_venus.c
@@ -1041,18 +1041,23 @@ static void venus_sfr_print(struct venus_hfi_device *hdev)
 {
 	struct device *dev = hdev->core->dev;
 	struct hfi_sfr *sfr = hdev->sfr.kva;
+	u32 size;
 	void *p;
 
 	if (!sfr)
 		return;
 
-	p = memchr(sfr->data, '\0', sfr->buf_size);
+	size = sfr->buf_size;
+	if (size > ALIGNED_SFR_SIZE)
+		return;
+
+	p = memchr(sfr->data, '\0', size);
 	/*
 	 * SFR isn't guaranteed to be NULL terminated since SYS_ERROR indicates
 	 * that Venus is in the process of crashing.
 	 */
 	if (!p)
-		sfr->data[sfr->buf_size - 1] = '\0';
+		sfr->data[size - 1] = '\0';
 
 	dev_err_ratelimited(dev, "SFR message from FW: %s\n", sfr->data);
 }

-- 
2.34.1

Re: [PATCH 4/4] media: venus: hfi: add a check to handle OOB in sfr region

Posted by Dmitry Baryshkov 2 weeks, 5 days ago

On Tue, Nov 05, 2024 at 02:24:57PM +0530, Vikash Garodia wrote:
> sfr->buf_size is in shared memory and can be modified by malicious user.
> OOB write is possible when the size is made higher than actual sfr data
> buffer.
> 
> Cc: stable@vger.kernel.org
> Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
> ---
>  drivers/media/platform/qcom/venus/hfi_venus.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
> index 50d92214190d88eff273a5ba3f95486f758bcc05..c19d6bf686d0f31c6a2f551de3f7eb08031bde85 100644
> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
> @@ -1041,18 +1041,23 @@ static void venus_sfr_print(struct venus_hfi_device *hdev)
>  {
>  	struct device *dev = hdev->core->dev;
>  	struct hfi_sfr *sfr = hdev->sfr.kva;
> +	u32 size;
>  	void *p;
>  
>  	if (!sfr)
>  		return;
>  
> -	p = memchr(sfr->data, '\0', sfr->buf_size);
> +	size = sfr->buf_size;
> +	if (size > ALIGNED_SFR_SIZE)
> +		return;

Why can't you just limit size to ALIGNED_SFR_SIZE, still allowing the
data to be captured?

> +
> +	p = memchr(sfr->data, '\0', size);
>  	/*
>  	 * SFR isn't guaranteed to be NULL terminated since SYS_ERROR indicates
>  	 * that Venus is in the process of crashing.
>  	 */
>  	if (!p)
> -		sfr->data[sfr->buf_size - 1] = '\0';
> +		sfr->data[size - 1] = '\0';
>  
>  	dev_err_ratelimited(dev, "SFR message from FW: %s\n", sfr->data);
>  }
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry

Re: [PATCH 4/4] media: venus: hfi: add a check to handle OOB in sfr region

Posted by Vikash Garodia 2 weeks, 4 days ago

On 11/5/2024 7:28 PM, Dmitry Baryshkov wrote:
> On Tue, Nov 05, 2024 at 02:24:57PM +0530, Vikash Garodia wrote:
>> sfr->buf_size is in shared memory and can be modified by malicious user.
>> OOB write is possible when the size is made higher than actual sfr data
>> buffer.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
>> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
>> ---
>>  drivers/media/platform/qcom/venus/hfi_venus.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
>> index 50d92214190d88eff273a5ba3f95486f758bcc05..c19d6bf686d0f31c6a2f551de3f7eb08031bde85 100644
>> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
>> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
>> @@ -1041,18 +1041,23 @@ static void venus_sfr_print(struct venus_hfi_device *hdev)
>>  {
>>  	struct device *dev = hdev->core->dev;
>>  	struct hfi_sfr *sfr = hdev->sfr.kva;
>> +	u32 size;
>>  	void *p;
>>  
>>  	if (!sfr)
>>  		return;
>>  
>> -	p = memchr(sfr->data, '\0', sfr->buf_size);
>> +	size = sfr->buf_size;
>> +	if (size > ALIGNED_SFR_SIZE)
>> +		return;
> 
> Why can't you just limit size to ALIGNED_SFR_SIZE, still allowing the
> data to be captured?
That should do as well. Updating above check to below would take care of it.
if (size > ALIGNED_SFR_SIZE)
    size = ALIGNED_SFR_SIZE;

Regards,
Vikash
> 
>> +
>> +	p = memchr(sfr->data, '\0', size);
>>  	/*
>>  	 * SFR isn't guaranteed to be NULL terminated since SYS_ERROR indicates
>>  	 * that Venus is in the process of crashing.
>>  	 */
>>  	if (!p)
>> -		sfr->data[sfr->buf_size - 1] = '\0';
>> +		sfr->data[size - 1] = '\0';
>>  
>>  	dev_err_ratelimited(dev, "SFR message from FW: %s\n", sfr->data);
>>  }
>>
>> -- 
>> 2.34.1
>>
>

Re: [PATCH 4/4] media: venus: hfi: add a check to handle OOB in sfr region

Posted by Bryan O'Donoghue 2 weeks, 5 days ago

On 05/11/2024 08:54, Vikash Garodia wrote:
> sfr->buf_size is in shared memory and can be modified by malicious user.
> OOB write is possible when the size is made higher than actual sfr data
> buffer.
> 
> Cc: stable@vger.kernel.org
> Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
> ---
>   drivers/media/platform/qcom/venus/hfi_venus.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
> index 50d92214190d88eff273a5ba3f95486f758bcc05..c19d6bf686d0f31c6a2f551de3f7eb08031bde85 100644
> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
> @@ -1041,18 +1041,23 @@ static void venus_sfr_print(struct venus_hfi_device *hdev)
>   {
>   	struct device *dev = hdev->core->dev;
>   	struct hfi_sfr *sfr = hdev->sfr.kva;
> +	u32 size;
>   	void *p;
>   
>   	if (!sfr)
>   		return;
>   
> -	p = memchr(sfr->data, '\0', sfr->buf_size);
> +	size = sfr->buf_size;
> +	if (size > ALIGNED_SFR_SIZE)
> +		return;
> +
> +	p = memchr(sfr->data, '\0', size);
>   	/*
>   	 * SFR isn't guaranteed to be NULL terminated since SYS_ERROR indicates
>   	 * that Venus is in the process of crashing.
>   	 */
>   	if (!p)
> -		sfr->data[sfr->buf_size - 1] = '\0';
> +		sfr->data[size - 1] = '\0';
>   
>   	dev_err_ratelimited(dev, "SFR message from FW: %s\n", sfr->data);
>   }
> 
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>