[PATCH] drm/mediatek: Replace all non-returning strlcpy with strscpy

[PATCH] drm/mediatek: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c b/drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c
index 2fc9214ffa82..4d39ea0a05ca 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c
@@ -295,7 +295,7 @@ static int mtk_hdmi_ddc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	strlcpy(ddc->adap.name, "mediatek-hdmi-ddc", sizeof(ddc->adap.name));
+	strscpy(ddc->adap.name, "mediatek-hdmi-ddc", sizeof(ddc->adap.name));
 	ddc->adap.owner = THIS_MODULE;
 	ddc->adap.class = I2C_CLASS_DDC;
 	ddc->adap.algo = &mtk_hdmi_ddc_algorithm;

Re: [PATCH] drm/mediatek: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Mon, May 22, 2023 at 03:53:06PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH] drm/mediatek: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Mon, 22 May 2023 15:53:06 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] drm/mediatek: Replace all non-returning strlcpy with strscpy
      https://git.kernel.org/kees/c/99ae1670e488

-- 
Kees Cook