diff mbox series

[v2,031/101] fbdev/hyperv_fb: Duplicate video-mode option string

Message ID 20230309160201.5163-32-tzimmermann@suse.de
State New
Headers
Series fbdev: Fix memory leak in option parsing |

Commit Message

Thomas Zimmermann March 9, 2023, 4 p.m. UTC 
  Assume that the driver does not own the option string or its substrings
and hence duplicate the option string for the video mode. As the driver
implements a very simple mode parser in a fairly unstructured way, just
duplicate the option string and parse the duplicated memory buffer. Free
the buffer afterwards.

Done in preparation of constifying the option string and switching the
driver to struct option_iter.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/hyperv_fb.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Comments

Michael Kelley (LINUX) March 12, 2023, 10:51 a.m. UTC | #1 
From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Thursday, March 9, 2023 8:01 AM
> 
> Assume that the driver does not own the option string or its substrings
> and hence duplicate the option string for the video mode. As the driver
> implements a very simple mode parser in a fairly unstructured way, just
> duplicate the option string and parse the duplicated memory buffer. Free
> the buffer afterwards.
> 
> Done in preparation of constifying the option string and switching the
> driver to struct option_iter.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/video/fbdev/hyperv_fb.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index 4a6a3303b6b4..edb0555239c6 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -903,17 +903,23 @@ static const struct fb_ops hvfb_ops = {
>  static void hvfb_get_option(struct fb_info *info)
>  {
>  	struct hvfb_par *par = info->par;
> -	char *opt = NULL, *p;
> +	char *options = NULL;
> +	char *optbuf, *opt, *p;
>  	uint x = 0, y = 0;
> 
> -	if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
> +	if (fb_get_options(KBUILD_MODNAME, &options) || !options || !*options)
>  		return;
> 
> +	optbuf = kstrdup(options, GFP_KERNEL);
> +	if (!optbuf)
> +		return;
> +	opt = optbuf;
> +
>  	p = strsep(&opt, "x");
>  	if (!*p || kstrtouint(p, 0, &x) ||
>  	    !opt || !*opt || kstrtouint(opt, 0, &y)) {
>  		pr_err("Screen option is invalid: skipped\n");
> -		return;
> +		goto out;
>  	}
> 
>  	if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
> @@ -922,12 +928,14 @@ static void hvfb_get_option(struct fb_info *info)
>  	    (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
>  	     x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8)) {
>  		pr_err("Screen resolution option is out of range: skipped\n");
> -		return;
> +		goto out;
>  	}
> 
>  	screen_width = x;
>  	screen_height = y;
> -	return;
> +
> +out:
> +	kfree(optbuf);
>  }
> 
>  /*
> --
> 2.39.2

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
diff mbox series

Patch

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 4a6a3303b6b4..edb0555239c6 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -903,17 +903,23 @@  static const struct fb_ops hvfb_ops = {
 static void hvfb_get_option(struct fb_info *info)
 {
 	struct hvfb_par *par = info->par;
-	char *opt = NULL, *p;
+	char *options = NULL;
+	char *optbuf, *opt, *p;
 	uint x = 0, y = 0;
 
-	if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
+	if (fb_get_options(KBUILD_MODNAME, &options) || !options || !*options)
 		return;
 
+	optbuf = kstrdup(options, GFP_KERNEL);
+	if (!optbuf)
+		return;
+	opt = optbuf;
+
 	p = strsep(&opt, "x");
 	if (!*p || kstrtouint(p, 0, &x) ||
 	    !opt || !*opt || kstrtouint(opt, 0, &y)) {
 		pr_err("Screen option is invalid: skipped\n");
-		return;
+		goto out;
 	}
 
 	if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
@@ -922,12 +928,14 @@  static void hvfb_get_option(struct fb_info *info)
 	    (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
 	     x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8)) {
 		pr_err("Screen resolution option is out of range: skipped\n");
-		return;
+		goto out;
 	}
 
 	screen_width = x;
 	screen_height = y;
-	return;
+
+out:
+	kfree(optbuf);
 }
 
 /*