2023-10-25 14:39:54

by Paul Kocialkowski

[permalink] [raw]

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

---

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 <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
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

2023-11-21 14:31:09

by Paul Kocialkowski

[permalink] [raw]

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

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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 <[email protected]>
> Reported-by: Dan Carpenter <[email protected]>
> 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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