[PATCH 1/2] drm/logicvc: Avoid possible overflow in layer buffer setup variables

[PATCH 1/2] drm/logicvc: Avoid possible overflow in layer buffer setup variables

[Paul Kocialkowski]

The buffer_sel, voffset and hoffset values are calculated from u32
values and might overflow under certain conditions.

Move them to u32 definitions instead of u8/u16 to avoid the issue.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: efeeaefe9be5 ("drm: Add support for the LogiCVC display controller")
---
 drivers/gpu/drm/logicvc/logicvc_layer.c | 6 +++---
 drivers/gpu/drm/logicvc/logicvc_layer.h | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.c b/drivers/gpu/drm/logicvc/logicvc_layer.c
index 464000aea765..eea22379d042 100644
--- a/drivers/gpu/drm/logicvc/logicvc_layer.c
+++ b/drivers/gpu/drm/logicvc/logicvc_layer.c
@@ -268,9 +268,9 @@ int logicvc_layer_buffer_find_setup(struct logicvc_drm *logicvc,
 	u32 layer_stride = layer_bytespp * logicvc->config.row_stride;
 	u32 base_offset = layer->config.base_offset * layer_stride;
 	u32 buffer_offset = layer->config.buffer_offset * layer_stride;
-	u8 buffer_sel = 0;
-	u16 voffset = 0;
-	u16 hoffset = 0;
+	u32 buffer_sel = 0;
+	u32 voffset = 0;
+	u32 hoffset = 0;
 	phys_addr_t fb_addr;
 	u32 fb_offset;
 	u32 gap;
diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.h b/drivers/gpu/drm/logicvc/logicvc_layer.h
index 4a4b02e9b819..a06feeda3abf 100644
--- a/drivers/gpu/drm/logicvc/logicvc_layer.h
+++ b/drivers/gpu/drm/logicvc/logicvc_layer.h
@@ -18,9 +18,9 @@
 #define LOGICVC_LAYER_ALPHA_PIXEL		1
 
 struct logicvc_layer_buffer_setup {
-	u8 buffer_sel;
-	u16 voffset;
-	u16 hoffset;
+	u32 buffer_sel;
+	u32 voffset;
+	u32 hoffset;
 };
 
 struct logicvc_layer_config {
-- 
2.42.0

[PATCH 2/2] drm/logicvc: Define max dimensions from USHRT_MAX

[Paul Kocialkowski]

Use the existing macro instead of redefining it.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
---
 drivers/gpu/drm/logicvc/logicvc_regs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/logicvc/logicvc_regs.h b/drivers/gpu/drm/logicvc/logicvc_regs.h
index 4aae27e9ba2b..0fc413fef6dd 100644
--- a/drivers/gpu/drm/logicvc/logicvc_regs.h
+++ b/drivers/gpu/drm/logicvc/logicvc_regs.h
@@ -10,7 +10,7 @@
 #ifndef _LOGICVC_REGS_H_
 #define _LOGICVC_REGS_H_
 
-#define LOGICVC_DIMENSIONS_MAX		(BIT(16) - 1)
+#define LOGICVC_DIMENSIONS_MAX		USHRT_MAX
 
 #define LOGICVC_HSYNC_FRONT_PORCH_REG	0x00
 #define LOGICVC_HSYNC_REG		0x08
-- 
2.42.0

Re: [PATCH 1/2] drm/logicvc: Avoid possible overflow in layer buffer setup variables

[Paul Kocialkowski]

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Hi folks,

On Wed 25 Oct 23, 15:09, Paul Kocialkowski wrote:
> The buffer_sel, voffset and hoffset values are calculated from u32
> values and might overflow under certain conditions.
> 
> Move them to u32 definitions instead of u8/u16 to avoid the issue.

Any chance to get a quick review on this simple fixup (and the next one)?
I can certainly push them myself after that.

Thanks,

Paul

> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Fixes: efeeaefe9be5 ("drm: Add support for the LogiCVC display controller")
> ---
>  drivers/gpu/drm/logicvc/logicvc_layer.c | 6 +++---
>  drivers/gpu/drm/logicvc/logicvc_layer.h | 6 +++---
>  2 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.c b/drivers/gpu/drm/logicvc/logicvc_layer.c
> index 464000aea765..eea22379d042 100644
> --- a/drivers/gpu/drm/logicvc/logicvc_layer.c
> +++ b/drivers/gpu/drm/logicvc/logicvc_layer.c
> @@ -268,9 +268,9 @@ int logicvc_layer_buffer_find_setup(struct logicvc_drm *logicvc,
>  	u32 layer_stride = layer_bytespp * logicvc->config.row_stride;
>  	u32 base_offset = layer->config.base_offset * layer_stride;
>  	u32 buffer_offset = layer->config.buffer_offset * layer_stride;
> -	u8 buffer_sel = 0;
> -	u16 voffset = 0;
> -	u16 hoffset = 0;
> +	u32 buffer_sel = 0;
> +	u32 voffset = 0;
> +	u32 hoffset = 0;
>  	phys_addr_t fb_addr;
>  	u32 fb_offset;
>  	u32 gap;
> diff --git a/drivers/gpu/drm/logicvc/logicvc_layer.h b/drivers/gpu/drm/logicvc/logicvc_layer.h
> index 4a4b02e9b819..a06feeda3abf 100644
> --- a/drivers/gpu/drm/logicvc/logicvc_layer.h
> +++ b/drivers/gpu/drm/logicvc/logicvc_layer.h
> @@ -18,9 +18,9 @@
>  #define LOGICVC_LAYER_ALPHA_PIXEL		1
>  
>  struct logicvc_layer_buffer_setup {
> -	u8 buffer_sel;
> -	u16 voffset;
> -	u16 hoffset;
> +	u32 buffer_sel;
> +	u32 voffset;
> +	u32 hoffset;
>  };
>  
>  struct logicvc_layer_config {
> -- 
> 2.42.0
> 

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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