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* [PATCH] tty: atmel_serial: fix a NULL pointer dereference
@ 2019-03-14  7:17 Kangjie Lu
  2019-03-14  8:25 ` Richard Genoud
  0 siblings, 1 reply; 5+ messages in thread
From: Kangjie Lu @ 2019-03-14  7:17 UTC (permalink / raw)
  To: kjlu
  Cc: pakki001, Richard Genoud, Greg Kroah-Hartman, Jiri Slaby,
	Nicolas Ferre, Alexandre Belloni, Ludovic Desroches,
	linux-serial, linux-arm-kernel, linux-kernel

In case dmaengine_prep_dma_cyclic fails, the fix return a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/tty/serial/atmel_serial.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..cf560d05008c 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1237,8 +1237,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	dma_cap_set(DMA_CYCLIC, mask);
 
 	atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
-	if (atmel_port->chan_rx == NULL)
+	if (atmel_port->chan_rx == NULL) {
+		ret = -EINVAL;
 		goto chan_err;
+	}
 	dev_info(port->dev, "using %s for rx DMA transfers\n",
 		dma_chan_name(atmel_port->chan_rx));
 
@@ -1257,6 +1259,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 
 	if (!nent) {
 		dev_dbg(port->dev, "need to release resource of dma\n");
+		ret = -EINVAL;
 		goto chan_err;
 	} else {
 		dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
@@ -1288,6 +1291,11 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		ret = -ENOMEM;
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
@@ -1300,7 +1308,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	atmel_port->use_dma_rx = 0;
 	if (atmel_port->chan_rx)
 		atmel_release_rx_dma(port);
-	return -EINVAL;
+	return ret;
 }
 
 static void atmel_uart_timer_callback(struct timer_list *t)
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH] tty: atmel_serial: fix a NULL pointer dereference
  2019-03-14  7:17 [PATCH] tty: atmel_serial: fix a NULL pointer dereference Kangjie Lu
@ 2019-03-14  8:25 ` Richard Genoud
  2019-03-15  7:21   ` [PATCH v2] " Kangjie Lu
  0 siblings, 1 reply; 5+ messages in thread
From: Richard Genoud @ 2019-03-14  8:25 UTC (permalink / raw)
  To: Kangjie Lu
  Cc: pakki001, Greg Kroah-Hartman, Jiri Slaby, Nicolas Ferre,
	Alexandre Belloni, Ludovic Desroches, linux-serial,
	linux-arm-kernel, linux-kernel

Hi,

Good catch !
Le 14/03/2019 à 08:17, Kangjie Lu a écrit :
> In case dmaengine_prep_dma_cyclic fails, the fix return a proper
> error code to avoid NULL pointer dereference.
> 
you could add:
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
So that -stable branches get this.

> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
>  drivers/tty/serial/atmel_serial.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 05147fe24343..cf560d05008c 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1237,8 +1237,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  	dma_cap_set(DMA_CYCLIC, mask);
>  
>  	atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx");
> -	if (atmel_port->chan_rx == NULL)
> +	if (atmel_port->chan_rx == NULL) {
> +		ret = -EINVAL;
>  		goto chan_err;
> +	}
>  	dev_info(port->dev, "using %s for rx DMA transfers\n",
>  		dma_chan_name(atmel_port->chan_rx));
>  
> @@ -1257,6 +1259,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  
>  	if (!nent) {
>  		dev_dbg(port->dev, "need to release resource of dma\n");
> +		ret = -EINVAL;
>  		goto chan_err;
>  	} else {
>  		dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
> @@ -1288,6 +1291,11 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  					 sg_dma_len(&atmel_port->sg_rx)/2,
>  					 DMA_DEV_TO_MEM,
>  					 DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		dev_err(port->dev, "Preparing DMA cyclic failed\n");
> +		ret = -ENOMEM;
IMHO, we don't really know why dmaengine_prep_dma_cyclic() failed, it
could be because it's already in use, or bad value, or...
(and anyway, we just check if the return value is < 0 in atmel _startup.)
Is there a specific reason you choose -ENOMEM ?
If not, maybe keeping this patch smaller with a simple dev_err()+goto
here would be a better choice.

> +		goto chan_err;
> +	}
>  	desc->callback = atmel_complete_rx_dma;
>  	desc->callback_param = port;
>  	atmel_port->desc_rx = desc;
> @@ -1300,7 +1308,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  	atmel_port->use_dma_rx = 0;
>  	if (atmel_port->chan_rx)
>  		atmel_release_rx_dma(port);
> -	return -EINVAL;
> +	return ret;
>  }
>  
>  static void atmel_uart_timer_callback(struct timer_list *t)
> 

Thanks !

Richard.

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH v2] tty: atmel_serial: fix a NULL pointer dereference
  2019-03-14  8:25 ` Richard Genoud
@ 2019-03-15  7:21   ` Kangjie Lu
  0 siblings, 0 replies; 5+ messages in thread
From: Kangjie Lu @ 2019-03-15  7:21 UTC (permalink / raw)
  To: kjlu
  Cc: pakki001, Richard Genoud, Greg Kroah-Hartman, Jiri Slaby,
	Nicolas Ferre, Alexandre Belloni, Ludovic Desroches,
	linux-serial, linux-arm-kernel, linux-kernel

Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..41b728d223d1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH] tty: atmel_serial: fix a NULL pointer dereference
  2019-03-15 17:16 ` [PATCH] " Kangjie Lu
@ 2019-03-18  7:28   ` Richard Genoud
  0 siblings, 0 replies; 5+ messages in thread
From: Richard Genoud @ 2019-03-18  7:28 UTC (permalink / raw)
  To: Kangjie Lu
  Cc: pakki001, Greg Kroah-Hartman, Jiri Slaby, Nicolas Ferre,
	Alexandre Belloni, Ludovic Desroches, linux-serial,
	linux-arm-kernel, linux-kernel

Le 15/03/2019 à 18:16, Kangjie Lu a écrit :
> In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
> error code to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> Fixes: 34df42f59a60 ("serial: at91: add rx dma support")
Acked-by: Richard Genoud <richard.genoud@gmail.com>

> 
> ---
> V2: simplified the patch as suggested by
> Richard Genoud <richard.genoud@gmail.com>
> ---
>  drivers/tty/serial/atmel_serial.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 05147fe24343..41b728d223d1 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
>  					 sg_dma_len(&atmel_port->sg_rx)/2,
>  					 DMA_DEV_TO_MEM,
>  					 DMA_PREP_INTERRUPT);
> +	if (!desc) {
> +		dev_err(port->dev, "Preparing DMA cyclic failed\n");
> +		goto chan_err;
> +	}
>  	desc->callback = atmel_complete_rx_dma;
>  	desc->callback_param = port;
>  	atmel_port->desc_rx = desc;
> 

Thanks !

Richard

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH] tty: atmel_serial: fix a NULL pointer dereference
  2019-03-15  8:22 Richard Genoud
@ 2019-03-15 17:16 ` Kangjie Lu
  2019-03-18  7:28   ` Richard Genoud
  0 siblings, 1 reply; 5+ messages in thread
From: Kangjie Lu @ 2019-03-15 17:16 UTC (permalink / raw)
  To: kjlu
  Cc: pakki001, Richard Genoud, Greg Kroah-Hartman, Jiri Slaby,
	Nicolas Ferre, Alexandre Belloni, Ludovic Desroches,
	linux-serial, linux-arm-kernel, linux-kernel

In case dmaengine_prep_dma_cyclic fails, the fix returns a proper
error code to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

---
V2: simplified the patch as suggested by
Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/atmel_serial.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 05147fe24343..41b728d223d1 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1288,6 +1288,10 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 					 sg_dma_len(&atmel_port->sg_rx)/2,
 					 DMA_DEV_TO_MEM,
 					 DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(port->dev, "Preparing DMA cyclic failed\n");
+		goto chan_err;
+	}
 	desc->callback = atmel_complete_rx_dma;
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-03-18  7:28 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2019-03-14  7:17 [PATCH] tty: atmel_serial: fix a NULL pointer dereference Kangjie Lu
2019-03-14  8:25 ` Richard Genoud
2019-03-15  7:21   ` [PATCH v2] " Kangjie Lu
2019-03-15  8:22 Richard Genoud
2019-03-15 17:16 ` [PATCH] " Kangjie Lu
2019-03-18  7:28   ` Richard Genoud

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