2014-10-31 22:41:09

by Alexey Khoroshilov

[permalink] [raw]
Subject: [PATCH] m501fb: don't return zero on failure path in sm501fb_probe()

If no framebuffers found, sm501fb_probe() breaks off initialization,
deallocates sm501fb_info, but returns zero. As a result, use after free
can happen in sm501fb_remove().

The patch adds -ENODEV as a return value in this case.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <[email protected]>
---
drivers/video/fbdev/sm501fb.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
index 9e74e8fbe074..8b98b011fc04 100644
--- a/drivers/video/fbdev/sm501fb.c
+++ b/drivers/video/fbdev/sm501fb.c
@@ -1988,6 +1988,7 @@ static int sm501fb_probe(struct platform_device *pdev)
if (info->fb[HEAD_PANEL] == NULL &&
info->fb[HEAD_CRT] == NULL) {
dev_err(dev, "no framebuffers found\n");
+ ret = -ENODEV;
goto err_alloc;
}

--
1.9.1


2014-11-06 14:23:09

by Tomi Valkeinen

[permalink] [raw]
Subject: Re: [PATCH] m501fb: don't return zero on failure path in sm501fb_probe()

On 01/11/14 00:40, Alexey Khoroshilov wrote:
> If no framebuffers found, sm501fb_probe() breaks off initialization,
> deallocates sm501fb_info, but returns zero. As a result, use after free
> can happen in sm501fb_remove().
>
> The patch adds -ENODEV as a return value in this case.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <[email protected]>
> ---
> drivers/video/fbdev/sm501fb.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
> index 9e74e8fbe074..8b98b011fc04 100644
> --- a/drivers/video/fbdev/sm501fb.c
> +++ b/drivers/video/fbdev/sm501fb.c
> @@ -1988,6 +1988,7 @@ static int sm501fb_probe(struct platform_device *pdev)
> if (info->fb[HEAD_PANEL] == NULL &&
> info->fb[HEAD_CRT] == NULL) {
> dev_err(dev, "no framebuffers found\n");
> + ret = -ENODEV;
> goto err_alloc;
> }
>
>

Thanks, queued for 3.19.

Tomi


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