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drm, video: fix use-before-NULL-check

PATCH In review Kees Cook 2 participants 2 messages Aug 27, 2010 – Aug 30, 2010

Subsystems (3)
DRM drivers Media (V4L/DVB) DRM misc
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Kees Cook

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#0 lore raw

PATCH 1/1 drm, video: fix use-before-NULL-check

Fix potential crashes due to use-before-NULL situations.

Signed-off-by Kees Cook <[email protected]>
---
 drivers/gpu/drm/drm_fb_helper.c           |    3 ++-
 drivers/media/video/em28xx/em28xx-video.c |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +2 -1
index de82e20..8dd7e6f 100644
@@ -94,10 +94,11 @@ static bool drm_fb_helper_connector_parse_command_line(struct drm_fb_helper_conn
 	int i;
 	enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
 	struct drm_fb_helper_cmdline_mode *cmdline_mode;
-	struct drm_connector *connector = fb_helper_conn->connector;
+	struct drm_connector *connector;
 
 	if (!fb_helper_conn)
 		return false;
+	connector = fb_helper_conn->connector;
 
 	cmdline_mode = &fb_helper_conn->cmdline_mode;
 	if (!mode_option)
drivers/media/video/em28xx/em28xx-video.c +2 -1
index 7b9ec6e..95a4b60 100644
@@ -277,12 +277,13 @@ static void em28xx_copy_vbi(struct em28xx *dev,
 {
 	void *startwrite, *startread;
 	int  offset;
-	int bytesperline = dev->vbi_width;
+	int bytesperline;
 
 	if (dev == NULL) {
 		em28xx_isocdbg("dev is null\n");
 		return;
 	}
+	bytesperline = dev->vbi_width;
 
 	if (dma_q == NULL) {
 		em28xx_isocdbg("dma_q is null\n");
Signature · 6 lines
1.7.1


-- 
Kees Cook
Ubuntu Security Team
Reviewed-by on v1 1/1
#1 lore raw
Quoted 34 lines · On Fri, 27 Aug 2010 14:07:19 -0700 Kees Cook <[email protected]> wrote:

Fix potential crashes due to use-before-NULL situations.

Signed-off-by Kees Cook <[email protected]>
---
 drivers/gpu/drm/drm_fb_helper.c           |    3 ++-
 drivers/media/video/em28xx/em28xx-video.c |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +2 -1
index de82e20..8dd7e6f 100644
@@ -94,10 +94,11 @@ static bool drm_fb_helper_connector_parse_command_line(struct drm_fb_helper_conn
 	int i;
 	enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
 	struct drm_fb_helper_cmdline_mode *cmdline_mode;
-	struct drm_connector *connector = fb_helper_conn->connector;
+	struct drm_connector *connector;
 
 	if (!fb_helper_conn)
 		return false;
+	connector = fb_helper_conn->connector;
 
 	cmdline_mode = &fb_helper_conn->cmdline_mode;
 	if (!mode_option)
drivers/media/video/em28xx/em28xx-video.c +0 -1
index 7b9ec6e..95a4b60 100644
@@ -277,12 +277,13 @@ static void em28xx_copy_vbi(struct em28xx *dev,
 {
 	void *startwrite, *startread;
 	int  offset;
-	int bytesperline = dev->vbi_width;

drivers/media/video/em28xx/em28xx-video.c static void em28xx_copy_vbi(struct em28xx *dev, · line 289

Quoted 10 lines
drivers/media/video/em28xx/em28xx-video.c +2 -0
+	int bytesperline;
 
 	if (dev == NULL) {
 		em28xx_isocdbg("dev is null\n");
 		return;
 	}
+	bytesperline = dev->vbi_width;
 
 	if (dma_q == NULL) {
 		em28xx_isocdbg("dma_q is null\n");

Look fine to me.

Reviewed-by Jesse Barnes <[email protected]>
Signature · 1 line
Jesse Barnes, Intel Open Source Technology Center