2015-02-12 15:47:50

by Sudip Mukherjee

[permalink] [raw]

Subject: [PATCH] video: fbdev: fix possible null dereference

---

we were dereferencing edid first and the NULL check was after
accessing that. now we are using edid only if we know that
it is not NULL.

Signed-off-by: Sudip Mukherjee <[email protected]>
---
drivers/video/fbdev/core/fbmon.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
index 9533859..868facd 100644
--- a/drivers/video/fbdev/core/fbmon.c
+++ b/drivers/video/fbdev/core/fbmon.c
@@ -624,9 +624,6 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize,
int num = 0, i, first = 1;
int ver, rev;

- ver = edid[EDID_STRUCT_VERSION];
- rev = edid[EDID_STRUCT_REVISION];
-
mode = kzalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
if (mode == NULL)
return NULL;
@@ -637,6 +634,9 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize,
return NULL;
}

+ ver = edid[EDID_STRUCT_VERSION];
+ rev = edid[EDID_STRUCT_REVISION];
+
*dbsize = 0;

DPRINTK(" Detailed Timings\n");
--
1.8.1.2

2015-02-20 12:13:51

by Tomi Valkeinen

[permalink] [raw]

Subject: Re: [PATCH] video: fbdev: fix possible null dereference

---

On 12/02/15 17:47, Sudip Mukherjee wrote:
> we were dereferencing edid first and the NULL check was after
> accessing that. now we are using edid only if we know that
> it is not NULL.
>
> Signed-off-by: Sudip Mukherjee <[email protected]>
> ---
> drivers/video/fbdev/core/fbmon.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
> index 9533859..868facd 100644
> --- a/drivers/video/fbdev/core/fbmon.c
> +++ b/drivers/video/fbdev/core/fbmon.c
> @@ -624,9 +624,6 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize,
> int num = 0, i, first = 1;
> int ver, rev;
>
> - ver = edid[EDID_STRUCT_VERSION];
> - rev = edid[EDID_STRUCT_REVISION];
> -
> mode = kzalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
> if (mode == NULL)
> return NULL;
> @@ -637,6 +634,9 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize,
> return NULL;
> }
>
> + ver = edid[EDID_STRUCT_VERSION];
> + rev = edid[EDID_STRUCT_REVISION];
> +
> *dbsize = 0;
>
> DPRINTK(" Detailed Timings\n");
>

Thanks, queued for 3.20.

Tomi

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