[PATCH] video: fbdev: fix possible null dereference

Subsystems: framebuffer core, framebuffer layer, the rest

STALE4229d

2 messages, 2 authors, 2015-02-20 · open the first message on its own page

[PATCH] video: fbdev: fix possible null dereference

From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date: 2015-02-12 15:47:50

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 <redacted>
---
 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

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

From: Tomi Valkeinen <hidden>
Date: 2015-02-20 12:13:51

On 12/02/15 17:47, Sudip Mukherjee wrote:
quoted hunk
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 <redacted>
---
 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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