[PATCH] dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved

[Gustavo A. R. Silva]

_xt_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after _xt_ has been null
checked.

This issue was detected with the help of Coccinelle.

Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.")
Signed-off-by: Gustavo A. R. Silva 
---
 drivers/dma/at_hdmac.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index fbab271..a861b5b 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -708,7 +708,7 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
 unsigned long flags)
 {
struct at_dma_chan  *atchan = to_at_dma_chan(chan);
-   struct data_chunk   *first = xt->sgl;
+   struct data_chunk   *first;
struct at_desc  *desc = NULL;
size_t  xfer_count;
unsigned intdwidth;
@@ -720,6 +720,8 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
return NULL;
 
+   first = xt->sgl;
+
dev_info(chan2dev(chan),
 "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, 
flags=0x%lx\n",
__func__, &xt->src_start, &xt->dst_start, xt->numf,
-- 
2.7.4

Re: [PATCH] dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved

[Ludovic Desroches]

On Mon, Nov 20, 2017 at 08:28:14AM -0600, Gustavo A. R. Silva wrote:
> _xt_ is being dereferenced before it is null checked, hence there is a
> potential null pointer dereference.
> 
> Fix this by moving the pointer dereference after _xt_ has been null
> checked.
> 
> This issue was detected with the help of Coccinelle.
> 
> Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.")
> Signed-off-by: Gustavo A. R. Silva 
Acked-by: Ludovic Desroches 

Thanks

> ---
>  drivers/dma/at_hdmac.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index fbab271..a861b5b 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -708,7 +708,7 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
>unsigned long flags)
>  {
>   struct at_dma_chan  *atchan = to_at_dma_chan(chan);
> - struct data_chunk   *first = xt->sgl;
> + struct data_chunk   *first;
>   struct at_desc  *desc = NULL;
>   size_t  xfer_count;
>   unsigned intdwidth;
> @@ -720,6 +720,8 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
>   if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
>   return NULL;
>  
> + first = xt->sgl;
> +
>   dev_info(chan2dev(chan),
>"%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, 
> flags=0x%lx\n",
>   __func__, &xt->src_start, &xt->dst_start, xt->numf,
> -- 
> 2.7.4
> 
> 
> ___
> linux-arm-kernel mailing list
> linux-arm-ker...@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH] dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved

[Vinod Koul]

On Mon, Nov 20, 2017 at 08:28:14AM -0600, Gustavo A. R. Silva wrote:
> _xt_ is being dereferenced before it is null checked, hence there is a
> potential null pointer dereference.
> 
> Fix this by moving the pointer dereference after _xt_ has been null
> checked.
> 
> This issue was detected with the help of Coccinelle.

Applied, thanks

-- 
~Vinod