2019-12-20 13:12:09

by Peter Ujfalusi

Subject: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
via already freed up memory.

Move the vchan_vdesc_fini() after invoking the callback to avoid this.

Fixes: 09d5b702b0f97 ("dmaengine: virt-dma: store result on dma descriptor")
Signed-off-by: Peter Ujfalusi <[email protected]>
---
drivers/dma/virt-dma.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
index ec4adf4260a0..256fc662c500 100644
--- a/drivers/dma/virt-dma.c
+++ b/drivers/dma/virt-dma.c
@@ -104,9 +104,8 @@ static void vchan_complete(unsigned long arg)
dmaengine_desc_get_callback(&vd->tx, &cb);

list_del(&vd->node);
- vchan_vdesc_fini(vd);
-
dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
+ vchan_vdesc_fini(vd);
}
}

--
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

2019-12-20 13:57:37

by Alexandru Ardelean

Subject: Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

On Fri, 2019-12-20 at 15:11 +0200, Peter Ujfalusi wrote:
> [External]
>
> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
> via already freed up memory.
>
> Move the vchan_vdesc_fini() after invoking the callback to avoid this.
>

Reviewed-by: Alexandru Ardelean <[email protected]>

> Fixes: 09d5b702b0f97 ("dmaengine: virt-dma: store result on dma
> descriptor")
> Signed-off-by: Peter Ujfalusi <[email protected]>
> ---
> drivers/dma/virt-dma.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
> index ec4adf4260a0..256fc662c500 100644
> --- a/drivers/dma/virt-dma.c
> +++ b/drivers/dma/virt-dma.c
> @@ -104,9 +104,8 @@ static void vchan_complete(unsigned long arg)
> dmaengine_desc_get_callback(&vd->tx, &cb);
>
> list_del(&vd->node);
> - vchan_vdesc_fini(vd);
> -
> dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
> + vchan_vdesc_fini(vd);
> }
> }
>

2019-12-20 14:04:06

by Alexandru Ardelean

Subject: Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

On Fri, 2019-12-20 at 15:11 +0200, Peter Ujfalusi wrote:
> [External]
>
> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
> via already freed up memory.
>
> Move the vchan_vdesc_fini() after invoking the callback to avoid this.
>

Apologies for seeing this too late: typo in title vcna_complete() ->
vchan_complete()


> Fixes: 09d5b702b0f97 ("dmaengine: virt-dma: store result on dma
> descriptor")
> Signed-off-by: Peter Ujfalusi <[email protected]>
> ---
> drivers/dma/virt-dma.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
> index ec4adf4260a0..256fc662c500 100644
> --- a/drivers/dma/virt-dma.c
> +++ b/drivers/dma/virt-dma.c
> @@ -104,9 +104,8 @@ static void vchan_complete(unsigned long arg)
> dmaengine_desc_get_callback(&vd->tx, &cb);
>
> list_del(&vd->node);
> - vchan_vdesc_fini(vd);
> -
> dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
> + vchan_vdesc_fini(vd);
> }
> }
>

2019-12-20 14:52:34

by Peter Ujfalusi

Subject: Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

On 20/12/2019 16.01, Ardelean, Alexandru wrote:
> On Fri, 2019-12-20 at 15:11 +0200, Peter Ujfalusi wrote:
>> [External]
>>
>> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
>> via already freed up memory.
>>
>> Move the vchan_vdesc_fini() after invoking the callback to avoid this.
>>
>
> Apologies for seeing this too late: typo in title vcna_complete() ->
> vchan_complete()

Yep, I also noticed after sending it, I hope Vinod is kind enough and
fix it up when applying ;)

- Péter

>> Fixes: 09d5b702b0f97 ("dmaengine: virt-dma: store result on dma
>> descriptor")
>> Signed-off-by: Peter Ujfalusi <[email protected]>
>> ---
>> drivers/dma/virt-dma.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
>> index ec4adf4260a0..256fc662c500 100644
>> --- a/drivers/dma/virt-dma.c
>> +++ b/drivers/dma/virt-dma.c
>> @@ -104,9 +104,8 @@ static void vchan_complete(unsigned long arg)
>> dmaengine_desc_get_callback(&vd->tx, &cb);
>>
>> list_del(&vd->node);
>> - vchan_vdesc_fini(vd);
>> -
>> dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
>> + vchan_vdesc_fini(vd);
>> }
>> }
>>


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

2019-12-23 07:53:54

by Vinod Koul

Subject: Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

On 20-12-19, 15:11, Peter Ujfalusi wrote:
> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
> via already freed up memory.
>
> Move the vchan_vdesc_fini() after invoking the callback to avoid this.

Applied, thanks

--
~Vinod

2019-12-23 07:55:47

by Vinod Koul

Subject: Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

On 20-12-19, 16:50, Peter Ujfalusi wrote:
>
>
> On 20/12/2019 16.01, Ardelean, Alexandru wrote:
> > On Fri, 2019-12-20 at 15:11 +0200, Peter Ujfalusi wrote:
> >> [External]
> >>
> >> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
> >> via already freed up memory.
> >>
> >> Move the vchan_vdesc_fini() after invoking the callback to avoid this.
> >>
> >
> > Apologies for seeing this too late: typo in title vcna_complete() ->
> > vchan_complete()
>
> Yep, I also noticed after sending it, I hope Vinod is kind enough and
> fix it up when applying ;)

In case it wasnt clear, yeah trivial changes while applying are no
hassle :)

--
~Vinod